Final Public Report Safety study for Liquid Logistics Shipping Concepthub.globalccsinstitute.com/sites/default/files/... · 2013-08-22 · Safety study for Liquid Logistics Shipping

DET NORSKE VERITAS

Final Public Report

Safety study for

Liquid Logistics Shipping Concept

Vopak / Anthony Veder

Report No./DNV Reg No.: / 12TUIBY-3

Rev 7, 2011-07-01

DET NORSKE VERITAS

Final report for Vopak / Anthony Veder

MANAGING RISK

Safety study for Liquid Logistics Shipping Concept

DNV Reg. No.: 12TUIBY-3 Revision No.: 7

Date : July 1, 2011 Page 1


DET NORSKE VERITAS BV

P.O.Box 9599

3007 AN Rotterdam, Netherlands

Tel: +31 (0) 10 2922600

Fax: +31 (0) 10 4797141

http://www.dnv.com

Org. No:

For:

VOPAK HOLDING

P.O. Box 863

3000 AW ROTTERDAM

Netherlands

Date of First Issue: 2010-11-01 Project No.: EP032156

Report No.: 12TUIBY-3 Organisation Unit: Solutions BeNeLux

Revision No.: 7 Subject Group:

Summary:

Final report of the safety study for the Liquid Logistics Shipping Concept. The safety report provides general

information on the properties and hazards of CO2. For each activity of the LLSC the potential hazardous

consequences and risks have been identified and assessed by means of a Quantitative Risk Assessment.

Prepared by: Name and Position

Peter Koers

Consultant

Maarten de Looij

Consultant

Signature

Verified by: Name and Position

Angunn Engbø, Senior Consultant

Matthé Bakker, Senior Consultant

Erwin Schouwenaars, Principal Consultant

Signature

Approved by: Name and Position

Piet Snaphaan

Head of DNV Solutions Benelux

Kaare Helle

Business Development Manager

Signature

No distribution without permission from the client or responsible

organisational unit (however, free distribution for internal use within

DNV after 3 years) Indexing Terms

No distribution without permission from the client or responsible

organisational unit Key Words

Strictly confidential Service Area

Unrestricted distribution Market Segment

Rev. No. / Date: Reason for Issue: Prepared by: Verified by: Accepted by:

3 / 2011-03-06 Draft final report issued

for clients comments

PKO, MDLO AENG, MWB,

SCHOUW

PSN

4 / 2011-04-05 Final report MWB MDLO PSN

5 / 2011-04-21 Small adjustments PKO MWB PSN



© 2010 Det Norske Veritas BV

Reference to part of this report which may lead to misinterpretation is not permissible.

DET NORSKE VERITAS


MANAGING RISK




Table of Contents

ABBREVIATIONS & DEFINITIONS ................................................................................... 4

CONCLUSIVE SUMMARY ................................................................................................... 5

1 INTRODUCTION ............................................................................................................. 8

1.1 Description of the LLSC project ................................................................................ 8

1.2 Scope of work ........................................................................................................... 10

1.3 Layout of report ........................................................................................................ 10

2 CO2 PROPERTIES AND HAZARDS ........................................................................... 11

2.1 CO2 characteristics ................................................................................................... 11

3 INCIDENTS INVOLVING CO2 .................................................................................... 20

3.1 Fire Extinguisher Systems ........................................................................................ 20

3.2 Pipeline Incidents ..................................................................................................... 21

3.3 Natural outgassing .................................................................................................... 22

4 METHODOLOGY .......................................................................................................... 24

4.1 Introduction .............................................................................................................. 24

4.2 Quantitative Risk Assessment .................................................................................. 24

4.3 Risk ........................................................................................................................... 26

4.4 Relevant QRA guidelines ......................................................................................... 29

5 CO2 TERMINAL AT EMITTER ALONG THE RHINE ........................................... 31

5.1 Scenarios .................................................................................................................. 31

5.2 Consequence assessment .......................................................................................... 40

5.3 Risk result & risk assessment ................................................................................... 45

6 TRANSPORT OF CO2 BY BARGE .............................................................................. 47

6.1 Introduction .............................................................................................................. 47

6.2 Scenarios .................................................................................................................. 48



7 TRANSPORT OF CO2 BY PIPELINE (LOW PRESSURE) ...................................... 56

7.1 Introduction .............................................................................................................. 56

DET NORSKE VERITAS


MANAGING RISK




7.2 LOC scenarios and frequencies ................................................................................ 56

7.3 Modeling pipeline LOC scenarios ............................................................................ 57


7.5 Risk assessment ........................................................................................................ 61

7.6 Conclusion ................................................................................................................ 66

8 CO2 TERMINAL AT THE PORT OF ROTTERDAM ............................................... 67

8.1 Introduction .............................................................................................................. 67

8.2 Scenarios .................................................................................................................. 69



9 TRANSPORT OF CO2 BY SEA GOING VESSELS ................................................... 87

9.1 Introduction .............................................................................................................. 87

9.2 Scenarios .................................................................................................................. 88


10 TRANSPORT OF CO2 BY PIPELINE (HIGH PRESSURE) ..................................... 93

10.1 Introduction .............................................................................................................. 93

10.2 LOC scenarios and frequencies ................................................................................ 94

10.3 Modeling pipeline LOC scenarios ............................................................................ 95


10.5 Risk assessment ........................................................................................................ 99

10.6 Conclusion .............................................................................................................. 101

11 CO2 OFFLOADING AT A SINGLE POINT MOORING SYSTEM ....................... 102

11.1 Introduction ............................................................................................................ 102

11.2 Scenarios ................................................................................................................ 103

11.3 Consequence assessment ........................................................................................ 104

11.4 Conclusions ............................................................................................................ 107

12 FINAL CONCLUSIONS ............................................................................................... 108

13 REFERENCES .............................................................................................................. 110

Appendix 1 Consequence results low pressure pipeline

Appendix 2 Consequence results high pressure pipeline

DET NORSKE VERITAS


MANAGING RISK




ABBREVIATIONS & DEFINITIONS

Bara Pressure in bar absolute

Barg Pressure in bar gauge

BLEVE Boiling Liquid Expanding Vapor Explosion

CO2 Carbon Dioxide

CCS Carbon Capture and Storage

DCMR The Dienst Centraal Milieubeheer Rijnmond

DNV Det Norske Veritas

DOT the US Department of Transportation

EOR Enhanced Oil Recovery

EPA US Environmental Protection Agency

ESD Emergency Shut Down

EU European Union

GCCSI Global CCS Institute

HDD Horizontal Directional Drilled

HP High Pressure

HSE Health, Safety and Environment

IChemE the Institution of Chemical Engineers

IGCC Integrated Gasification Combined Cycles

LLSC Liquid Logistics Shipping Concept

LOC Loss of Containment

LP Low Pressure

MBRA the Reference Manual Bevi Risk Assessments

MTA Million Metric Tons Annually

OEL Occupational Exposure Limit

OGP the international Association of Oil and Gas Producers

OPS the US Office of Pipeline Safety

PPM Parts Per Million

PHAST Process Hazard Analysis Software Tool

PHMSA the US Pipelines and Hazardous Materials Safety Administration

PSA the Norwegian Petroleum Safety Authority

QRA Quantitative Risk Assessment

RCI Rotterdam Climate Initiative

RIVM the National Institute for Public Health and the Environment

ROAD the Rotterdam Afvang en Opslag Demonstratieproject

Safeti-NL Software for the Assessment of Flammable, Explosive and Toxic Impacts (Dutch version)

VROM the Ministry of Housing, Spatial Planning and the Environment

DET NORSKE VERITAS


MANAGING RISK




CONCLUSIVE SUMMARY

Introduction

Cintra is developing a CO2 Liquid Logistics Shipping Concept (LLSC) that will provide CO2

emitters a complete logistical transportation solution for their captured CO2 from their site to an

offshore storage location. Vopak and Anthony Veder, as Joint venture partners in Cintra, have

received a fund from the Global CCS institute (GCCSI) to study the Liquid Logistics Shipping

Concept.

DNV has been asked to perform a safety study of the different activities as input for the Safety,

Health and Environment report of the LLSC.

Objective

The objective of the safety study is to provide Vopak, its partners and the public with an

understanding of the possible hazardous consequences and risks posed by the different CO2

activities of the LLSC to the surrounding areas. The results of the identified consequences and

risks are compared with the applicable Dutch risk criteria and, where needed, recommendations

are made for possible mitigation measures to reduce the risks.

Approach

The safety study addresses the potential hazardous consequences and risks associated with the

following activities of the LLSC:

Local CO2 terminal at one of the CO2 sources (named “inland emitter E” or “Emitter E”)

including liquefaction, storage and loading activities.

Transport of CO2 by barge from emitter E to the central CO2 terminal in the Port of

Rotterdam.

Pipeline transport of low pressure CO2 from different emitters located in the Port of

Rotterdam to the CO2 terminal in the Port of Rotterdam.

CO2 terminal in the Port of Rotterdam (including liquefaction, storage, compression and

(un)loading activities).

Onshore part of the pipeline transport of high pressure CO2 from the CO2 terminal in the

Port of Rotterdam to an offshore sink.

Transport of CO2 by sea going vessels from the CO2 terminal location in the Port of

Rotterdam to open sea.

CO2 offloading at open sea at a single point mooring system.

For each activity the possible Loss of Containment (LOC) scenarios have been identified. The

consequences, dangerous CO2 concentrations and lethality ranges, of these LOC scenarios have

been calculated. Together with the failure frequency of these LOC scenarios the cumulative risk

of most of the activities was calculated and the results were compared with the applicable Dutch

DET NORSKE VERITAS


MANAGING RISK




risk criteria. The identification of the LOC scenarios and their corresponding failure frequencies

followed the Dutch guidelines for Quantitative Risk Assessments.

Results

The safety study simulated the LOC scenarios (e.g. leak of a pipeline) for the different LLSC

activities. The table below presents the maximum hazardous effect distances, the 1% lethality

distance and the maximum risk levels for the different activities.

The maximum effect distance of a certain LOC scenarios is the maximum distance where a CO2

concentration of 50,000 ppm could occur. The CO2 concentration of 50,000 ppm is the

concentration where 1% of the humans exposed for 30 minutes are expected to die. However, the

concentrations at the maximum effect distance are, most of the time, not sustained for such a long

period of time.

Therefore the lethality distances are calculated. The lethality distance of a certain LOC scenario

is determined by calculating the dose at a specific location and using this as input for the CO2

probit function to calculate the fatalities. The dose is a combination of concentration and

exposure time. The 1% lethality distance, presented in the table below, is the distance where 1%

of the humans are expected to die.

The individual risk is the risk of a fatality at a specific location when a person would be present at

that location 100% of the time. The individual risk is calculated by combining the risks of all

identified LOC scenario of an activity, which means that the individual risk presents the total risk

of an activity. The risk of a LOC scenario is a combination of the effects and the probability of

that scenario to occur.

Activity Maximum effect distance

(m)

1% Lethality distance

(m)

Maximum individual

risk (per year)

CO2 emitter terminal 540 280 10-5

Barges 780 510 10-8

Low pressure pipeline 440 380 10-7

CO2 terminal in Rotterdam 680 680 10-5

Seagoing vessels 950 710 -

High pressure pipeline 1980 740 10-6

CO2 offloading offshore 100 - -

The results show that the maximum 1% lethality distances of the activities is in the range of 280

meters up to 740 meters from the location of the accidental CO2 release. This means that the

different activities might affect persons present in the direct vicinity. However, these distances do

not say anything about the risk of the activities since likelihood has not been taken into account

here.

DET NORSKE VERITAS


MANAGING RISK




The individual risk levels appear to be the highest in the direct vicinity of the terminals, which is

caused by the process installations and the (un)loading activities over there. In the direct vicinity

of the terminals no vulnerable objects, such as housing, should be present and this is also not the

case. The CO2 transportation activities do not result in onshore risk levels higher than 10-7

per

year. For the seagoing vessels and the offshore offloading no risk calculations were performed

since no vulnerable objects are located in these areas and therefore a risk assessment is not

needed according to the Dutch risk criteria.

Conclusions

Based on the results it can be concluded that all of the CO2 activities could pose an effect on the

direct vicinity when an unintentional release occurs. However, the corresponding risk levels

appear to be below the Dutch risk criteria. Therefore, in DNV‟s opinion the safety risks

associated with the Liquid Logistics Shipping Concept are acceptable for all of the considered

activities.

This means that, besides designing and operating according to industry standards / practice, no

extra mitigations measures are needed to reduce the risk for the activities.

DET NORSKE VERITAS


MANAGING RISK




1 INTRODUCTION

Cintra is developing a CO2 Liquid Logistics Shipping Concept (LLSC) that will provide CO2

emitters a complete logistical transportation solution for their captured CO2 from their site to an

offshore storage location. Vopak and Anthony Veder, as Joint Venture partners in Cintra, have

received a fund from the Global CCS institute (GCCSI) to study the Liquid Logistics Shipping

Concept.

The objective of this study is to develop a Liquid Logistics Shipping Concept for a robust,

reliable and safe CO2 transport system, with minimum costs for the entire CO2 transport system

(from capture flange to storage well head).

The knowledge and expertise from project partners, vendors, consultants, designers and other

third parties was gathered and combined into the LLSC. The work was organized according work

streams, the first focusing on the optimization of the overall supply chain, the second focusing on

the design of the individual unit operations (jointly comprising the entire chain) and finally the

Safety/Health/Environment (SHE) aspects of the full chain.

DNV has been asked to perform a safety study of the different activities for the SHE report of the

LLSC.

1.1 Description of the LLSC project

The LLSC will take the captured CO2 from the emitters to an intermediate storage site (i.e. Port

of Rotterdam) via either barge (in liquefied phase) or pipeline (gaseous phase). From this

intermediate storage location (CO2 Hub/terminal) the liquid CO2 is shipped by a sea going vessel

to the permanent offshore storage sites, where the ship will discharge on a stand alone basis via

an offshore infrastructure (e.g. turret, submersed flexible hoses or loading tower) that links the

vessel to the sub sea completion/template (Figure 1-1).

Figure 1-1: logistic CO2 route via sea going vessel

In addition compressed CO2 is transferred from this CO2 Hub to the storage sites by means of

offshore pipelines (Figure 1-2).

DET NORSKE VERITAS


MANAGING RISK




Figure 1-2: logistic CO2 route via pipeline

The CO2 Hub will combine and link pipeline systems and barging/shipping routes, and will

include functions like intermediate liquid storage, liquefaction of CO2 and vaporization of liquid

CO2. The CO2 is envisaged to be able to follow all four different routes through the terminal:

both with and without a phase change (from gas to liquid and vice versa) at the terminal.

The concept anticipates on the use of offshore sinks, depleted gas fields or oil fields for Enhanced

Oil Recovery (EOR), because of the public posture and on land permitting issues that are

believed to push the majority of the CO2 volume to sea.

Selection of CO2 sources is done on expected availability of usable sources, distance from the

CO2 Hub and the available waterways for possible barge transport from CO2 capture to CO2

terminal. The selected CO2 sources for the study are:

Table 1-1: CO2 sources

Remarks to table

1. For emitter A, the captured CO2 will be compressed and transported through a pipeline to an offshore depleted

gas field (Sink A). Compression will be done on a site near the power plant. Normally, this CO2 is not routed to

the CO2 Hub.

DET NORSKE VERITAS


MANAGING RISK




2. Annual flows are based CO2 flow as is, including impurities. Differences between normal flow and maximum

flow are based on annual operating hours, seasonal and daily flow fluctuations. Hourly design flows will be

calculated from the maximum annual flow, divided by 8765 hours per year.

1.2 Scope of work

DNV‟s safety study will address the potential hazardous consequences and risks associated with

the following activities of the LLSC:

CO2 terminal at inland emitter E (including liquefaction, storage and loading activities).

Transport of CO2 by barge from emitter E to the CO2 terminal in the Port of Rotterdam.

Pipeline transport of low pressure CO2 from different emitters located in the Port of

Rotterdam to the CO2 terminal in the Port of Rotterdam.

CO2 terminal in the Port of Rotterdam (including liquefaction, storage, compression and

(un)loading activities).

Onshore part of the pipeline transport of high pressure CO2 from the CO2 terminal in the

Port of Rotterdam to an offshore sink.

Transport of CO2 by sea going vessels from the terminal location in the Port of Rotterdam

to open sea.

CO2 offloading at open sea at a loading tower.

1.3 Layout of report

The first two chapters of the safety report provide some general information on the properties and

hazards of CO2 and describe some reported incidents related to CO2.

The safety study assesses the consequences and risks associated with the LLSC activities which are

calculated by means of a Quantitative Risk Assessment (QRA). Chapter 4 provides information on

the concept and basic methodology of a QRA, the used guidelines for these QRA's, the concept

of risk and the used risk criteria.

Chapters 5 through 11 address the potential hazardous consequences and risks associated with the

activities of the LLSC and assesses for each activity whether the risk is below the risk criteria.

Chapter 12 draws conclusions out of the result of the different assessments.

DET NORSKE VERITAS


MANAGING RISK




2 CO2 PROPERTIES AND HAZARDS

In this chapter an overview will be given of the properties and hazards of CO2. Furthermore, it

explains the possible effect of an unintentional release.

2.1 CO2 characteristics

Pure CO2 is at ambient pressure and temperature a colorless and, at low concentrations, odorless

gas with a density of 1.98 kg/m3, which makes it heavier than air. CO2 is not very reactive, as it is

fully oxidized, and not flammable.

Figure 2-1 shows the pressure-temperature phase diagram of pure CO2. The axes correspond to

the pressure and temperature. The phase diagram shows the phase boundaries lines between the

three phases of solid, liquid, and gaseous CO2. At a phase boundary two phases will be present at

once.

CO2 is at atmospheric pressure and temperature a vapor. At atmospheric pressure the gas deposits

directly to the solid state at temperatures below −78 °C and solid CO2 sublimes directly to gas

phase at temperature above −78 °C. The triple point (the combination of pressure and temperature

where CO2 is present in all 3 physical phases) is at 5.2 bara and -56.6 ºC. Liquid CO2 can only be

formed at a pressure and temperature higher than the triple point. The critical point (where liquid

and vapor densities become equal and the phase boundary disappears, forming a dense phase) is

at a pressure of 73.3 bara and a temperature of 31.1º C.

Figure 2-1: Phase diagram of pure CO2

DET NORSKE VERITAS


MANAGING RISK




The general operating window of the LLSC (for shipment, pipelines and terminal) is depicted in

the phase diagram. The CO2 process conditions for transport per ship are chosen near the triple

point because of the highest density and thereby maximizing the transport capacity. The CO2

process conditions for transport per pipeline depends whether it is a pipeline from the emitter to

the terminal (no liquid CO2 allowed) or from the terminal to one of the sinks. The most energy

efficient phase to transport CO2 in pipelines is in dense phase condition.

2.1.1 Asphyxiation / Toxicity

Although CO2 is a constituent of air (around 385 ppm or 0.0385%), exposure to high CO2

concentration can lead to asphyxiation, similar as for inert gases, and intoxication.

Asphyxiation is a condition of severely deficient supply of oxygen to the body that arises

from being incapable of normal respiration. Asphyxia is usually characterized by air

hunger but the urge to breathe is triggered by rising carbon dioxide levels in the blood

rather than diminishing oxygen levels.

The toxic effects of CO2 are due to the influence it has on the pH of the blood and thereby

effecting the respiratory, cardiovascular and central nervous systems [Ref 1].

Thus, CO2 exposure can give rise to a variety of effects, including an increase in inhalation and

heart rate, in blood pressure and it can induce cardiovascular effects. The absence of an effective

remedial action will lead to unconsciousness, brain damage or death.

Table 2-1 shows the occupational exposure limits of different references. An occupational

exposure limit (OEL) is an upper limit of the acceptable concentration of a hazardous substance

in workplace air. The limit is set to protect against health effects.

Table 2-1: Occupational exposure limits

http://en.wikipedia.org/wiki/Air_hunger

http://en.wikipedia.org/wiki/Air_hunger

http://en.wikipedia.org/wiki/Death

DET NORSKE VERITAS


MANAGING RISK




The occupational exposure limit differs between references. However, it is clear that the

maximum exposure limit of CO2 depends on the exposure time: a higher CO2 concentration has

got a lower maximum exposure time.

The safety study assesses the acute effects of CO2 to determine the possibility of fatalities and

does not consider injuries or the possible long-term effects of CO2 exposure. The acute health

effects that are seen following inhalation of high concentrations of CO2 are presented in Table

2-2.

Table 2-2: Acute health effects of high concentrations of inhaled CO2 [Ref 2]

The time to death is dependent on the concentration and exposure duration as well as the health

conditions of a person.

The methodology used to determine the number of fatalities from a case of CO2 exposure is

described in the following section.

2.1.2 Probit function of CO2

A Probit function is used in the simulation software to determine the lethal effects arising from an

exposure to certain concentration levels of a toxic in air during a certain period of time. Although

CO2 is not recognized as a dangerous substance by EU legislation it has clearly been shown to

exhibit toxic properties (See paragraph 2.1.1). However, at the moment there is not yet a Probit

function prescribed by the National Institute for Public Health and the Environment (RIVM).

Therefore, DNV will use the Probit function derived in the report “Veiligheidsanalyse

Ondergrondse Opslag van CO2 in Barendrecht, 2008” [Ref 3]. For this Probit function there is

already correspondence [Ref 4] with RIVM, where it was considered conservative by RIVM and

not leading to an underestimation of the consequences/risks. Table 2-3 shows the concentrations

derived by Tebodin and the Ministry of Housing, Spatial Planning and the Environment (VROM)

and which are used in the consequence and risk calculations.

DET NORSKE VERITAS


MANAGING RISK




Table 2-3: Concentrations used for the consequence and risk calculations

Concentration(ppm / % v/v) Type of value Reference

27,500 / 2.75% alarm value, below this value no

serious harm on humans is expected

publication of the VROM Inspectie:

Intervention values dangerous goods 2006

50,000 / 5% LC01, 1% of the human exposed for

30 minutes are expected to die

Tebodin probit relation

100,000 / 10% LC100, 100% of the human exposed

for 30 minutes are expected to die

Tebodin probit relation

2.1.3 Impurities

CO2 that has been captured from an (industrial) activity (such as the CO2 that will be handled by

the CO2 distribution hub) may contain impurities which would have practical impacts on CO2

transport and storage systems and also potential health, safety and environmental impacts. The

types and concentrations of impurities depend on the type of capture process and the plant design.

Table 2-4 gives indicative CO2 stream compositions for coal and gas fires power plants and for

different capture processes.

The major impurities in CO2 are well known but there is little published information on the fate

of any trace impurities in the feed gas such as heavy metals. CO2 from post-combustion solvent

scrubbing processes normally contains low concentrations of impurities. Many of the existing

post-combustion capture plants produce high purity CO2 for use in the food industry.

CO2 from pre-combustion physical solvent scrubbing processes typically contains about 1-2% H2

and CO and traces of H2S and other sulfur compounds. Integrated Gasification Combined Cycles

(IGCC) plants with pre-combustion capture can be designed to produce a combined stream of

CO2 and sulfur compounds, to reduce costs and avoid the production of solid sulfur.

The CO2-rich gas from oxy-fuel processes contains oxygen, nitrogen, argon, sulfur and nitrogen

oxides and various other trace impurities. This gas will normally be compressed and fed to a

cryogenic purification process to reduce the impurities concentrations to the levels required to

avoid two-phase flow conditions in the transportation pipelines [Ref 5].

Table 2-4: Indicative compositions of CO2 stream % by volume [Ref 6]

DET NORSKE VERITAS


MANAGING RISK




Some of these impurities are flammable (CO, H2, H2S, CH4) and / or toxic (CO, NO2, SO2, H2S).

However, the CO2 stream will not be flammable since the concentration of the impurities is very

low and therefore flammable effects will not be considered in the safety study. Toxic impurities

could increase the toxicity of the CO2 stream compared to a pure CO2 stream. Nevertheless, the

CO2 stream will be considered as pure CO2 and the impurities will not be considered in the safety

study. The reason is that it is expected that the used probit, see section 2.1.2, is conservative

enough to take into account the possible higher toxicity of the small concentration of toxic

impurities.

2.1.4 Release of CO2

When there is a leak or rupture in for example a storage container or pipeline, CO2 will discharge

into the atmosphere. A release can be broken down into 2 distinct stages, discharge and

dispersion. An example of the 2 stages is visualized in Figure 2-2 and Figure 2-3.

The discharge is characterized by the release rate through a hole and depends mainly on the

pressure inside the equipment, the size of the hole and the phase of the release (liquid, gas or two-

phase). The release rate decreases with time as the equipment depressurizes.

Once a material has been released into the atmosphere and has expanded so that its internal

pressure is equal to atmospheric pressure, it will travel away from the release point under the

influence of its own initial velocity, the wind, buoyancy and diffusion forces. This is the

dispersion stage of the release.

Figure 2-2: Discharge zone from fluid inventory

DET NORSKE VERITAS


MANAGING RISK




Figure 2-3: Dispersion stage of a CO2 release [Ref 7]

Loss of Containment (LOC) scenarios can occur under different process conditions, including

from gaseous, liquid or dense phase inventories. These releases could occur above or below

water, on for example offshore platforms, sub-sea, below or above ground and within densely

packed and congested plant areas. The process conditions and surrounding have an impact on the

discharge and dispersion of a material.

The next sections go more into depth on the discharge and dispersion stages of CO2 releases.

2.1.4.1 Stage 1: Discharge

The discharge behavior of a CO2 release depends mainly on a) the pressure difference between

the inside of the containment and the environment, b) whether it is catastrophic rupture of a

vessel or a release from a hole or pipe, c) the phase of the released (liquid, gas or two-phase) and

d) whether the discharge is into air, water or underground:

a) The bigger the pressure differential, the bigger the discharge velocity will be

b) Catastrophic rupture versus leak

During a catastrophic rupture of a vessel the complete inventory is released directly. Upon release

the stored material expands to ambient pressure. Dispersion will take over during the loss of

expansion energy.

Releases from a hole in a vessel or a broken pipe will form a CO2 jet which expands and moves

away due to the initial momentum of the release. Dispersion will take over after the ambient

pressure is reached and the momentum has dissipated.

c) Phase of the release

Accidental releases from vessels with liquid and dense phase CO2 inventories are significantly

more complex. In these cases, as the CO2 enters the atmosphere it makes a transition from the

DET NORSKE VERITAS


MANAGING RISK




liquid phase to a two-phase gas/solid mixture where the solid fraction depends on the upstream

conditions. During this transition the fluid expands in a characteristic “tulip” shape. The solids

particles which are formed will become entrained in the gaseous release where it will sublime

into the cloud. Under certain conditions some solids may rain out on the ground (more

information on the specifics of solids formation is written in section 2.1.4.2).

d) Discharge into air, water or underground

For accidental releases which occur under water from sub-sea pipelines, sea going vessels or

barges, the CO2 must rise to the surface before being dispersed. The CO2 will spread as it rises in

the bubble column and the size of the area at the surface can be much larger than the area of the

hole. The size of the area is likely to increase with increasing release depths. Furthermore, the

CO2 release will loose momentum which may significantly increase the hazardous distance.

However, part of the CO2 will dissolve in the water and will not take part in the dispersion.

Using the North Sea as an example, at the sea bed the pressure and temperature are around 10

bara (corresponding to the hydrostatic pressure of 100 meter water column) and 4°C,

respectively. At these conditions, CO2 is in the gas phase. A pipeline could, however, contain

liquid or dense phase CO2. Hence at a pipeline rupture or fitting failure at the sea bed there could

be a very complex region of mixing between the CO2 (undergoing phase change) and the water.

However, within a short distance from the release, gaseous bubbles of CO2 will have formed

which then rise through the water forming a bubble column. The evolution of this bubble column

must be tracked using some form of model to give the size of the release at the sea surface.

2.1.4.2 Solid formation

Thermodynamic theory determines that CO2, when released to the atmosphere, will be released

either as a pure vapor or as a two phase mixture of solid phase CO2 and vapor phase CO2, since

liquid phase CO2 cannot exist at atmospheric pressure.

The Temperature/Entropy (T-s) diagram for CO2 is useful to determine whether the released CO2

will be a pure vapor or a solid/vapor mixture. Figure 2-4 illustrates the CO2 T-s diagram, where

three different initial conditions (denoted A, B and C) are highlighted. An isenthalpic approach,

no exchange of enthalpy with the surrounding, is assumed as basic assumption for establishing

the post-release condition, which is marked as A*, B

*and C

* at the line of constant pressure of 1

bar.

From Figure 2-4 it can be seen that for the starting condition represented by the point C, an

expansion along the constant enthalpy line would result in the supercritical CO2 cooling into the

vapor phase (point C*). Hence, the path of expansion does not end in the region of solid and

vapor and no solids are expected to form upon release for the given initial conditions.

For the initial conditions A and B, it can be seen that the lines of constant enthalpy enter into the

liquid+vapor region and then into the solid+vapor region (points A* and B

*), and therefore solid

CO2 will be formed. The relative proportion of solid versus vapor can be estimated from where

the constant enthalpy line intersects with the 1 bar line using the Lever Rule. For example, if the

intersection point is close to the vapor line (i.e. right end of the horizontal 1 bar line) there would

be virtually no solid CO2 present, however, if the intersection point was approximately half way

along the 1 bar line then the masses of solid and vapor would be approximately the same. For the

DET NORSKE VERITAS


MANAGING RISK




illustrative example in Figure 2-4,

the A* post-release point will have

the larger portion of solids in the

mixture compared to B*.

Large quantities of solid CO2 may

collect in the vicinity of release

points and spread some distance

over adjacent plant and equipment.

As these deposits warm up, carbon

dioxide gas will be produced as the

solids changes directly into a gas.

The localized high concentration of

CO2 that this produces represents a

significant hazard to personnel.

Solid formation will be taken into account for those scenarios for which solid formation is

applicable. The methodology to take solid formation into account will be explained in the

appropriate LOC scenarios.

2.1.4.3 Stage 2: Dispersion

Apart from the physical properties of the released material and the phase of the release (liquid

two phase or gas) the dispersion is dependent on the atmospheric conditions like temperature,

wind speed, atmospheric stability class and to a lesser extent the atmospheric pressure (which is

normally assumed to be constant).

As the CO2 cloud disperses with the wind, it spreads due to gravitational (density) effects and

mixes with air due to atmospheric turbulence (characterized by a stability measure). Processes

also affecting this mixing include heat transfer with the air and re-evaporation of condensed

moisture, diffusion and buoyancy.

Eventually the CO2 cloud will reach a point of neutral density, at which point dense gas processes

cease to be important and atmospheric turbulence dominates the mixing.

2.1.5 Cryogenic Impact

The release of liquid or dense phase CO2 to the atmosphere, whether through a vent or leak, will

result in a phase change as the CO2 depressurizes through the vent or leak. Where the inventory

temperature is below the critical point temperature the rapid expansion combined with the phase

change will result in a very high velocity, very low temperature, two phase flow. Anyone caught

in the extremely cold jet of gas and entrained -78°C solids will suffer cryogenic burns and

potentially, impact injuries. Inhalation of such a cold atmosphere would also cause severe internal

injuries.

Figure 2-4: Thermodynamic path of a CO2 release

DET NORSKE VERITAS


MANAGING RISK




These cryogenic effects are not considered in the risk calculations as it is unlikely (as cryogenic

effects are limited to close vicinity of release and no third parties will be present there) to

increase the hazard range of a spill caused by the toxicity of CO2.

2.1.6 Instantaneous depressurization

When a pressurized liquid is depressurized instantaneously a situation can occur referred to as a

superheated liquid phase (a liquid above its boiling point) in which the liquid will vaporize

suddenly in an explosive manner resulting in a blast wave and risk of flying fragments of the

containment (i.e. pipe or vessel). This is called a Boiling Liquid Expanding Vapor Explosion

(BLEVE).

Only under specific process conditions (temperature and pressure) a BLEVE can occur as

sufficient heat and pressure is needed to build up the process that could lead to a BLEVE. The

BLEVE envelope indicates the range of temperatures and pressures where the gas or gas mixture

could lead to a BLEVE following instantaneous depressurization.

However, the CO2 storage conditions (-50 °C and 7 bara) at the terminal and the shipping are

outside the so called BLEVE envelope and therefore no excessive superheat is available.

Hydrocarbons or other flammables will not be present at the terminal and the ships and therefore

a CO2 BLEVE scenario for the LLSC will not show the snow ball effects as are experienced for

i.e. LPG BLEVE‟s where the flammable vapors created by the boil-off are ignited and accelerate

the further boil-off of the liquid. For this reason a CO2 BLEVE is referred to as a “cold BLEVE”.

DET NORSKE VERITAS


MANAGING RISK




3 INCIDENTS INVOLVING CO2

This chapter presents some reported incidents, related to CO2, showing the potential harmful

effects on humans. Taking notion of such incidents can be very valuable as lessons can be learned

and insight is created into what can happen when things go as not intended. This chapter is

largely based on the report Mapping of potential Health, Safety and Environment (HSE) issues

related to large-scale capture, transport and storage of CO2, prepared by DNV for the

Norwegian Petroleum Safety Authority (PSA) [Ref 10].

3.1 Fire Extinguisher Systems

A comprehensive review of carbon dioxide incidents related to use in fire protection was

undertaken by the US Environmental Protection Agency (EPA) [Ref 2], which reviewed

governmental, military, public, and private document archives. The findings are summarized as

follows:

From 1975 to 2000, a total of 51 carbon dioxide incident records were located that reported a

total of 72 deaths and 145 injuries resulting from accidents involving the discharge of carbon

dioxide from indoor fire extinguishing systems.

Prior to 1975, a total of 11 incident records were located that reported a total of 47 deaths and

7 injuries involving carbon dioxide. Twenty of the 47 deaths occurred in England prior to

1963; however, the cause of these deaths is unknown.

The review indicates that the majority of reported incidents occurred during maintenance on or

around the carbon dioxide fire protection system. In many of the situations where carbon dioxide

exposure led to death or injury during maintenance operations, the discharge resulted from

personnel inadvertently touching, hitting, or depressing a component of the system. In some

cases, personnel did not adhere to the precautionary measures prescribed. In other cases, the

safety measures were followed, but other accidental discharge mechanisms occurred.

More recently (August 2008), a lacquer-making plant in Moenchengladbach in Germany [Ref 11]

had a fire break out in an area where wooden pallets were stored causing the carbon dioxide

extinguishing system to discharge, extinguishing the fire and putting the building into alarm,

automatically closing all the exterior doors while the CO2 discharged into the building. Because

of a mechanical flaw, one of the fire doors failed to seal properly and the CO2-enriched

atmosphere began leaking out into the surrounding area. Ambient external conditions were warm

and calm (i.e. no wind) at the time of the incident and as the CO2-enriched atmosphere escaped

from the building it accumulated in the vicinity to the extent that an engine of a response vehicle

suddenly stopped running and three firefighters collapsed. These firefighters were outside at the

time and, probably due to their lack of understanding of the hazards, were not wearing breathing

equipment. The incident resulted in a reported 107 respiratory injuries with three needing to be

revived by rescuers. 19 people were transported to hospital.

DET NORSKE VERITAS


MANAGING RISK




3.2 Pipeline Incidents

In the US, the Department of Transportation (DOT) regulates the design, construction, operation

and maintenance, and spill response planning for CO2 pipelines. The DOT administers pipeline

regulations through the Office of Pipeline Safety (OPS) within the Pipelines and Hazardous

Materials Safety Administration (PHMSA). Although CO2 is listed as a Class 2.2 (non-

flammable gas) hazardous material under DOT regulations the agency applies nearly the same

safety requirements to CO2 pipelines as it does to pipelines carrying hazardous liquids such as

crude oil, gasoline, and anhydrous ammonia [Ref 12].

Statistics on pipeline incidents can be found at OPS within the U.S. Department of

Transportation, Pipeline and Hazardous Materials Safety Administration [Ref 13], and is

summarized below:

In the period 1986-2001: 11 incidents related to pipeline transport of CO2 are reported with a

total of one fatality and two injuries. According to the incident log, the fatality was related to

welding work and not as a direct consequence of pipeline operation. 9 of the incidents were

related to the pipeline (all onshore), whereas the remaining two occurred at the pumping

station.

In the period 2002- 2008: 18 incidents related to pipeline transport of CO2 are reported with

no fatalities and injuries. 9 of these incidents were solely related to the onshore pipeline itself,

whereas the remaining were related to incidents at pump/metering stations or terminal/tank

farm piping and equipment, including sumps.

The failure modes of all the 29 reported incidents from 1986-2008 are grouped and presented in

Figure 3-1.

Figure 3-1: Grouping of reported failure modes for CO2 pipeline systems

In comparison to the above statistics, there were 5,610 accidents causing 107 fatalities and 520

injuries related to natural gas and hazardous liquids (excluding CO2) pipelines during the period

1986-2006. Reported data for natural gas pipelines in the US showed the principal causes of

pipeline accidents were outside force (35%), corrosion (32%), other (17%), weld and pipe

failures (13%) and operator error (3%). The category „„outside force‟‟ includes „„human error‟‟

accidents principally as a result of third party damage by contractors, farmers and utility workers.

The „„other‟‟ category includes incidents such as vandalism, train derailment and improper

operation of manual valves [Ref 14].

CORROSION MATERIAL AND/OR WELD FAILURES EQUIPMENT FAILURE OTHER (e.g. EXCAVATION

DAMAGE/INCORRECT OPERATION)

DET NORSKE VERITAS


MANAGING RISK




A mile-by-mile comparison is made by Gale and Davidson [Ref 14], and according to their study

CO2 pipelines have a frequency of incident of 0.33 per 1000 km per year, whereas natural gas and

hazardous liquids pipelines have a frequency of 0.17 and 0.82, respectively.

Table 3-1: Statistics of pipeline incident in the USA [Ref 14]

Natural gas transmission (1986–2001)

Hazardous liquids (1986–2001)

CO2 (1990–2001)

No. of incidents 1287 3035 10

No. of injuries 217 249 0

No. of fatalities 58 36 0

No. incidents (per 1000 km pipeline per year)

0.17 0.82 0.33

As seen from the numbers in Table 3-1, the frequency of incidents of CO2 pipelines between

1990 and 2001 was higher than that of natural gas pipelines. It is not clear why the frequency of

incidents of CO2 pipelines is higher. A possible explanation could be that the confidence interval

is larger due to the low sample number. Analysts suggest that, as the number of CO2 pipelines

expands to support CCS, statistically the number of incidents involving CO2 should be similar to

those for natural gas transmission [Ref 15].

3.3 Pressure vessel

In 1988 an accident involving a tank of CO2 occurred at a plant in Worms, Germany in 1988 [Ref

8]. A tank of 30 tons capacity was shattered into a number of pieces and only 20% of the tank

was present in the original premises after the explosion. Most of the tank was propelled 300

meters into the Rhine. The Worms investigation concluded that the vessel failed catastrophically,

most likely due to overpressure from overheating and an inoperative relief valve. Based on the

damages, number of fragments and the distances these were spread out from the plant area,

fatalities and injuries it was speculated that the failure caused a cold CO2 BLEVE. In addition to

the Worms incidents, a CO2 storage vessel failure in Hungary in 1969 was believed to cause a

BLEVE to occur.

3.4 Natural outgassing

Lake Nyos is one of only three lakes in the world known to be saturated with carbon dioxide - the

others are Lake Monoun, also in Cameroon about 100 km away, and Lake Kivu in Rwanda. A

magma chamber beneath the region is an abundant source of carbon dioxide, which seeps up

through the lake bed, charging the waters of Lake Nyos with an estimated 90 million tons of CO2.

Lake Nyos is thermally stratified, with layers of warm, less dense water near the surface floating

on the colder, denser water layers near the lake's bottom. Over long periods, carbon dioxide gas

seeping into the cold water at the lake's bottom is dissolved in great amounts.

Most of the time, the lake is stable and the CO2 remains in solution in the lower layers. However,

over time the water becomes supersaturated, and if an event such as an earthquake or volcanic

eruption occurs, large amounts of CO2 may suddenly come out of solution.

DET NORSKE VERITAS


MANAGING RISK




On August 21, 1986, a limnic eruption (a lake overturn) occurred at Lake Nyos which triggered

the sudden release of about 1.6 million tons of CO2. The gas spilled over the northern lip of the

lake into a valley, resulting in the death of some 1,700 people within 20 km of the lake, mostly

rural villagers, as well as 3,500 livestock. Worst affected villages were Cha, Nyos, and Subum.

About 4,000 inhabitants fled the area, and many of these developed respiratory problems, lesions,

and paralysis as a result of the gases. Prior to the Lake Nyos a similar incidents with sudden

outgassing of CO2 occurred at Lake Monoun in 1984, killing 37 local residents.

The scale of these disasters led to much study on how a recurrence could be prevented. Estimates

of the rate of carbon dioxide entering the lake suggested that outgassing could occur every 10-30

years. Several researchers independently proposed the installation of degassing columns from

rafts in the lake [Ref 16]. The principle is simple: a pump lifts water from the bottom of the lake,

heavily saturated with CO2, until the loss of pressure begins releasing the gas from the 2-phase

fluid and thus makes the process self-powered.

DET NORSKE VERITAS


MANAGING RISK




4 METHODOLOGY

4.1 Introduction

The safety study assesses the risk associated with the CO2 distribution hub and the consequence and

risk are calculated by means of a Quantitative Risk Assessment (QRA). Paragraph 4.2 explains the

concept of a QRA and the basic methodology. Paragraph 4.3 provides general information on the

two kinds of risk (individual and societal risk) used in the safety study and on the Dutch risk criteria.

Paragraph 4.4 describes the used guidelines for performing the QRA.

4.2 Quantitative Risk Assessment

A QRA gives insight into the risks to human life of a certain activity by calculating the potential

effects of a variety of scenarios as well as considering the probability of occurrence of these

scenarios.

A QRA tries to answer five simple questions. Beside each question, the technical term is listed

for that activity in the risk assessment process:

What can go wrong? Hazard Identification

How bad? Consequence Modeling

How often? Frequency Estimation

So What? Risk Assessment

What do I do? Risk Management

A simple representation of the QRA process is given in Figure 4-1. This shows how the various

questions mentioned above are related.

The first stage is system definition, defining the installation or the activity whose risks are to be

analyzed. The scope of work for the risk assessment should define the boundaries for the study,

identifying which activities are included and which are excluded, and which phases of the

installation‟s life are to be addressed.

Then, hazard identification consists of a qualitative review of possible accidents which may

occur, based on previous accident experience, guidelines provided by legislation or judgment

where necessary. It has the purpose of selecting a list of possible failure cases which are suitable

for quantitative modeling.

Once the hazards have been identified, frequency analysis estimates how likely it is for the

accidents to occur. The frequencies can be obtained from guidelines provided by legislation,

analysis of previous accident experience or by some form of theoretical modeling.

DET NORSKE VERITAS


MANAGING RISK




In parallel with the frequency

analysis, consequence

modeling evaluates the

resulting effects if the accidents

occur, and their impact on

personnel, equipment and

structures, the environment or

business.

When the frequencies and

consequences of each modeled

event have been estimated, they

can be combined to form

measures of overall risk.

Up to this point, the process has

been purely technical, and is

known as risk analysis. The

next stage is to introduce

criteria which are yardsticks to

indicate whether the risks are

“intolerable” or “negligible” or

to make some other value-

judgment about their

significance. This step begins to introduce non-technical issues of risk acceptability and decision

making, and the process is then known as risk assessment. Sometimes, it is referred to as

quantified risk assessment, QRA, to distinguish it from the more subjective assessment which can

be performed intuitively without numerical analysis of frequencies or consequences.

In order to make the risks acceptable, risk reduction measures may be necessary. The benefits

from these measures can be evaluated by repeating the QRA with them in place, thus introducing

an iterative loop into the process. The economic costs of the measures can be compared with their

risk benefits using cost-benefit analysis.

Iteration can also be used to refine either the failure case definitions or the frequency estimation,

through revised assumptions leading to better definition of the failures or their frequencies. This

is likely after the first estimates of the risks have been completed.

Iteration can be used to carry out sensitivity analysis.

Data collection and

description of system

Hazard Identification

(Development of

scenarios)

Collection and analysis of

complementary data

Consequence analysisFrequency analysis

Risk determination

Risk assessmentRisk criteria

Re-evaluation

Proposal of risk

mitigation measures

Finally Accepted

Situation

Figure 4-1: QRA risk assessment procedure

DET NORSKE VERITAS


MANAGING RISK




4.3 Risk

The definition of risk is given as, “An estimate of economic loss or loss of human life measured

in terms of both the incident likelihood and the magnitude of the loss.”

Risks to people can be expressed in two complementary forms:

Individual risk - the risk experienced by an individual person.

Societal (or group) risk - the risk experienced by the whole group of people exposed to the

hazard.

These are described separately below.

4.3.1 Individual Risk

Individual risk is defined formally by the IChemE (1992) [Ref 17] as the frequency at which an

individual may be expected to sustain a given level of harm from the realization of specified

hazards. It is usually taken to be the risk of death, and usually expressed as a risk per year.

Individual risk may be calculated in various ways, and although each is consistent with the above

definition, the results may differ substantially. In order to clarify the different approaches, three

main types of individual risk may be distinguished:

Location-specific individual risk (LSIR). This is used to indicate the risk at a particular

location. It is the risk for a hypothetical individual who is positioned there for 24 hours per

day, 365 days per year. It is a standard output from a QRA. In onshore studies, the

geographical variation of LSIR may be represented by is-risk contour plots and used for land-

use planning.

Individual-specific individual risk (ISIR). This is a more realistic estimate of the risk for an

individual, taking account of them being at different locations for different lengths of time

and (in an offshore study) being offshore for only around 20 weeks per year.

Average individual risk. This is the average ISIR over the group of people included in the

data. It is usually calculated from historical data as:

Individual risk = Number of people at risk / Number of fatalities per year

Although these different forms are widely used in offshore QRA, use of the distinguishing terms

LSIR, ISIR and average IR is less common. This often causes confusion when comparing

individual risks from different studies. Also, when comparing risk results with criteria, it is

important that consistent definitions are used.

In the safety study the calculated individual risk is the Location-specific individual risk since

the used risk criteria are set for this definition of individual risk.

DET NORSKE VERITAS


MANAGING RISK




4.3.2 Societal Risk

Societal (or group) risk is the risk experienced in a given time period by the whole group of

personnel exposed. It reflects the severity of the hazard and the number of people in proximity to

it. It is usually taken to refer to the risk of death, and usually expressed as a risk per year.

Societal risks are defined by the IChemE (1992) [Ref 17] as the relationship between the

frequency and the number of people suffering a given level of harm from the realization of

specified hazards. This definition excludes single-figure measures such as annual fatality rate (see

below) and so the wider definition above is preferred.

Societal risks may be expressed in the form of:

FN curves, showing the relationship between the cumulative frequency (F) and number of

fatalities (N).

Annual fatality rates, in which the frequency and fatality data is combined into a convenient

single measure of group risk.

In the safety study the societal risk is expressed in the form of FN curves since the used risk

criteria are set for this form of societal risk.

FN curves are frequency-fatality plots, showing the cumulative frequencies (F) of events

involving N or more fatalities (see example in Figure 4-2). They are derived by sorting the

frequency-fatality (fan) pairs from each outcome of each accidental event, and summing them to

form cumulative frequency-fatality (FN) co-ordinates for the plot. The cumulative form is used to

ensure that monotonic (steadily declining) curves are obtained even when some sizes of accident

do not occur in the analysis.

Figure 4-2: Example of FN curves, for two generic platform designs

DET NORSKE VERITAS


MANAGING RISK




4.3.3 Risk criteria

The risk criteria used by the National Institute for Public Health and the Environment (RIVM) are

defined in the Dutch National Environmental Policy Plan (1989). The criteria apply to industrial

plants (e.g. chemical plants), but are also applied to rail marshalling yards and transport of

dangerous goods (via pipelines, on water and on roads).

The Dutch risk criteria implemented in the Decree External Safety Establishments 2011 are

quantitative risk criteria formulated as Location Specific Individual Risk, to ensure that no

individual is exposed to excessive risk. Decisions by the authorities (i.e. environmental permits

for establishments and urban planning close to existing establishments) must also take societal

risk into consideration.

The Individual risk criteria are:

Vulnerable objects (e.g. houses): maximum of 10-6

deaths/year

Less vulnerable objects (e.g. offices): maximum of 10-6

deaths/year

Distinction is made between „vulnerable objects‟ and „objects with limited vulnerability‟. The

latter category includes scattered residences (less than two per ha), small shops and hotels,

business areas, recreational objects, and objects which serve as infrastructure (electricity supply,

telephone exchanges, air traffic control towers, etc.). Vulnerable objects are residences, areas for

children, the aged, the sick, or the disabled (schools, preschools, nursing homes, hospitals, etc.)

large (centers containing) stores and hotels (defined as more than 1500 m2 of floor space) and

campgrounds for over 50 people.

For vulnerable objects, a limit value for location-based risk of 10-6

per year must not be exceeded.

For objects with limited vulnerability, the same value applies as an orientation norm and may be

exceeded under certain conditions.

The societal risk criterion is an orientation norm which means that it sets a maximum allowable

risk level, but the authorities can diverge from it and approve an environmental permit even if the

societal risk is higher than the criteria. An approval can only be given by a thorough motivation

with considering the interests of the different stakeholders. Different societal risk criteria are used

for establishments and transportation.

The societal risk criteria for establishments are (see also Figure 4-3):

10-5

per year for 10 fatalities

10-7


10-9


The societal risk criteria for transportation are (see also Figure 4-3):

10-4


10-6


10-8


DET NORSKE VERITAS


MANAGING RISK




Figure 4-3: Societal risk criteria for transport and establishments

4.4 Relevant QRA guidelines

Worldwide, different QRA methodologies exist to define appropriate accident scenarios for

QRA‟s. Because the LLSC study focuses mainly on the development of an initiative in the

Netherlands, the safety study will follow as much as possible the Dutch regulations and

guidelines for safety studies.

The Dutch regulations for external safety and the corresponding guidelines for QRA modeling

are divided into three parts:

Establishments

Pipelines

- High pressure natural gas

- Flammable liquids

- Other materials (e.g. CO2)

Transport of hazardous substances

- Water

- Road

- Rails

The LLSC contains terminals, pipelines and transport over water. Therefore, all three parts are

applicable for the safety study of the LLSC study. The next sections provide more detail of the

different items of the safety study with their corresponding guidelines.

DET NORSKE VERITAS


MANAGING RISK




4.4.1 CO2 terminals

Two types of CO2 terminals are part of the LLSC study, the terminal at the emitter and the

transfer/distribution terminal in the Port of Rotterdam (CO2 hub). The Reference Manual Bevi

Risk Assessments (MBRA) [Ref 20] contains guidelines for quantitative risk modeling of

facilities of dangerous goods (establishments) and is applicable for the terminals. These

guidelines are used as part of the Dutch implementation of the European Seveso II Directive. It

prescribes the hazard scenarios to take into consideration, generic failure frequencies and

proposes detailed guidelines on how to model. It can be regarded as one of the most

comprehensive guidelines for risk modeling available in the world. The Reference Manual Bevi

Risk Assessments (MBRA) has also been applied to vessels (barges or sea vessels) when docked

and loading/unloading) at one of the terminals.

4.4.2 CO2 transport by pipelines

One way of transporting the CO2 from the emitters is by pipelines. From the terminal in the port

of Rotterdam the CO2 can also be transported by a pipeline to an offshore location. For pipelines

containing natural gas (high pressure) or flammable liquids different regulations are available

[Ref 18], [Ref 19]. For pipelines containing other compound the Reference Manual Bevi Risk

Assessments [Ref 20] is used. In 2011 a new guideline for pipelines will be introduced (AmvB,

Besluit Externe Veiligheid Buisleidingen / Decree External Safety Pipelines) which integrates the

guidelines for the different types of pipelines. For this study the Reference Manual Bevi Risk

Assessments is used for the CO2 pipelines.

4.4.3 CO2 transport by barges or seagoing vessels

Another way of transporting the CO2 from the emitters is by barges. The CO2 is liquefied to make

it as dense as possible and then transported over water by barges to the central terminal in the

Port of Rotterdam. From the central terminal in the Port of Rotterdam the CO2 can also be

transported over water by a seagoing vessel to an offshore location.

The QRA guideline for transport (i.e. the actual shipping) of dangerous goods is part II of the

PGS3 (Purple Book) [Ref. 26]. At the moment parts are being revised and updated into a new

guideline. Transport over water is divided between inland shipping and sea vessels. Part II of the

PGS 3 (Purple Book) will also be in the updated version of the guideline for inland shipping. For

sea vessels the Protocol Risk Analysis Sea and Inland Shipping [Ref 21] will be used. The

difference between the two guidelines is that for the inland shipping generic leak probabilities are

used and for the sea vessels the leak probabilities are calculated by the energy available on the

water. The identification of risk related to sea vessels is restricted to when the vessels is inside the

port area as no external safety risks exist once the vessel has left port (since no population is

present).

DET NORSKE VERITAS


MANAGING RISK




5 CO2 TERMINAL AT EMITTER E

The purpose of the CO2 terminal at the emitter is receiving, liquefaction, temporary store and

export of the captured CO2. The CO2 will be received from the emitter next to the CO2 terminal.

After liquefaction and storage the CO2 will be send out via barges.

This chapter identifies and assesses the consequences and risks of the different activities, such as

liquefaction and storage, of the CO2 terminal at

the emitter site.

Description of the terminal

The CO2 terminal will receive CO2 from the

CO2 capture installation from the emitter. The

captured CO2 will enter the terminal via two

incoming pipelines. The CO2 will be liquefied

in the liquefier and stored in two storage

vessels. CO2 from the storage tanks will be

transferred to the loading facility where it is

loaded into barges. On a yearly basis 250

barges will be loaded from the storage tanks.

An overview of the CO2 terminal at the emitter

is given in Figure 5-1.

5.1 Scenarios

The next paragraphs will discuss and provide the characteristics of the different parts of

equipment located on the CO2 terminal. Besides the process conditions, the paragraph will

discuss the possible LOC scenarios that are considered.

5.1.1 Storage tanks

The terminal contains two identical pressurized storage tanks without a bund. Each storage tank

contains a volume of 3250 m3. The CO2 is stored at a temperature of -50 °C at a pressure of 7

barg. During storage of pressurized liquid CO2, different loss of containment scenarios can occur.

Table 5-1 summarizes the loss of containment scenarios for pressures storage tanks as prescribed

by the MBRA.

Table 5-1: Failure frequencies for pressurized storage tanks

Scenario Failure frequency (per year)

Pressured storage tank

Rupture of the storage tank 5*10-7

Release of total volume of tank in 10 minutes 5*10-7

Leakage of tank through 10 mm hole 1*10-5

Figure 5-1: Overview of the CO2 terminal

DET NORSKE VERITAS


MANAGING RISK




A BLEVE scenario is not taken into account because the storage conditions of the tanks are

outside the so called BLEVE envelope and there is no possibility of fire impingement since there

are no flammable materials onsite.

5.1.2 Barging

All of the CO2 will be exported via transport over water. It is assumed that 250 barges per year

will transport 1 Mtons of CO2 from the emitter site to the CO2 terminal in the Port of Rotterdam.

To receive the barges and load the liquid CO2, the terminal will be equipped with a loading jetty.

The jetty consists of a 12 inch loading arm and a 6 inch vapor return arm. The liquid CO2 is

loaded with a mass flow of 1000 ton/hr. The vapor return arm is not modeled in this QRA

because of the low amount of mass that flows through the arm.

Table 5-2 summarizes the characteristics of the loading activities.

Table 5-2: Characteristic of the loading activities

Jetty Number of

(un)loading activities

per yr

Number of

(un)loading hr

per activity [hr]

hours of (un)loading

activities per yr [hr]

diameter

[inch]

flow per loading

arm [kg/s]

2 250 4 1000 12 278

During the loading of CO2 different loss of containment scenarios can occur. Table 5-3

summarizes the loss of containment scenarios for shipping and loading activities as prescribed by

the MBRA.

The CO2 terminal will be equipped with an automatic leak detection system which will

automatically activate the emergency shut down (ESD) valves. In case of a rupture of a pipeline

the automatic shutdown valves will be operated and the valve will be closed. The MBRA

prescribes that the probability of failure per operation of automatic shut down valves equals

0.001. The time to require closing the blocking valves equals 120 seconds. In case the closing of

the blocking valves will fail the duration of the outflow will be 1800 seconds.

The automatic shutdown system does not work for leakages because it is assumed that the gas

detection is not capable of detecting the small amount of gas that will be released in case of a

leakage.

Table 5-3: Failure frequencies for shipping and loading activities

Scenario Failure frequency

(un)Loading of refrigerated gas tanker

S1.a Rupture of the loading arm and ESD action 2.7*10-8

per hr

S1.b Rupture of the loading arm without ESD action 3*10-11

per hr

S2 Leakage of the loading arm 3*10-7

per hr

The terminal jetty is located in a dedicated harbor where no other ships are allowed. Collision of

ships to the moored CO2 barges is therefore not likely.

DET NORSKE VERITAS


MANAGING RISK




More detailed information about the scenarios that are modeled within this study is found in

Table 5-4.

Table 5-4: Details of failure scenarios of the loading jetty

Number

of

loading

arm

Scenario Orifice

diameter

[inch]

Exit

velocity

[m/s]

Mass

rate

[kg/s]

Time[s] Failure

frequency

per arm

[1/hr]

Failure

frequency

per arm

[1/yr]

Failure

frequency

per jetty

[1/yr]

1 S1.a 12 4.8 417 120 2.7 x 10-8

2.7 x 10-5

2.7 x 10-5

1 S1.b 12 4.8 417 1800 3.0 x 10-9

3.0 x10-6

3.0 x 10-8

1 S2 1.2 116.9 18.4 1800 3.0 x 10-7

3.0 x 10-4

3.0 x 10-4

5.1.3 Pumps

Liquid CO2 from the storage tanks is pumped to the barges with a centrifugal pump. The pump

will transfer the CO2 with a mass flow of 278 kg/s. The characteristic of the loading pump is

given in Table 5-5.

Table 5-5: Characteristic of the pump

Pump Pressure

suction

line [bar]

Temperature

[°C]

Diameter suction

line [inch]

Mass flow

rate [kg/s]

Duration of

the loading

[hr]

Time

fraction in

use [-]

Loading pump 7 -50 20 278 4 0.11

During the pumping of CO2 different loss of containment scenarios can occur. Table 5-6

summarizes the loss of containment scenarios for pumping activities as prescribed by the MBRA.

Table 5-6: Initial failure frequency for centrifugal pumps


Centrifugal pump with seals

S1.a Rupture of the pump suction line and ESD action 1.0*10-4

per year

S1.b Rupture of the pump suction line arm without ESD action 1.0*10-7

per year

S2 Leakage of the loading arm 4.4*10-3

per year

Table 5-7 will give detailed information about the scenarios that are modeled within this study.

The mass flow for the rupture scenarios in both tables is 1.5 x the mass flow mentioned in Table

5-5. The factor 1.5 is used to take into account the increasing pump flow due to the pipeline

ruptures.

DET NORSKE VERITAS


MANAGING RISK




Table 5-7: Details of failure scenarios loading pump (during unloading)

Number

of

pumps

Scenario Orifice

diameter

[inch]

Exit velocity

[m/s]

Mass

rate

[kg/s]

Time[s] Failure

frequency

per pump

[1/yr]

Time

fraction

in use [-]

Total

failure

frequency

[1/yr]

1 S1.a 12 4.8 417 120 1.0 x 10-4

0.11 1.3 x 10-5

1 S1.b 12 4.8 417 1800 1.0 x 10-7

0.11 1.3 x 10-8

1 S2 1.2 116.9 18.4 1800 4.4 x 10-3

0.11 5.8 x 10-4

Table 5-8: Details of failure scenarios loading pump (no unloading activities)

Number

of

pumps

Scenario Orifice

diameter

[inch]

Exit velocity

[m/s]

Mass

rate

[kg/s]

Time[s] Failure

frequency

per pump

[1/yr]

Time

fraction

in use [-]

Total

failure

frequency

[1/yr]

1 S1.a 20 116 2348 18 1.0 x 10-4

0.89 8.9 x 10-5

1 S2 2 116 46.8 1800 4.4 x 10-3

0.89 3.9 x 10-3

5.1.4 Piping

CO2 will be received at the terminal via two incoming pipelines from the CO2 capture

installation. The 24 and 10 inch pipeline will deliver a continuously mass flow of 38 kg/s to the

terminal. The incoming CO2 will be liquefied in the liquefier where after it will be transported to

the storage tanks with 38 kg/s through a 4 inch pipeline.

The liquid CO2 from the storage tanks will be transferred with a 12 inch pipeline to the loading

facility. An overview of the pipelines is given in Figure 5-2. More detailed information about the

characteristics of the different pipelines that are modeled is found in Table 5-9.

Figure 5-2: Layout drawing of the modeled piping

DET NORSKE VERITAS


MANAGING RISK




Table 5-9: Characteristic of the above ground piping

Piping trajectory Pressure suction

line [bar]

Temperature

[°C]

Diameter

[inch]

Mass flow

rate [kg/s]

Time fraction

in use [-]

Incoming CO2 line A from emitter 1.2 -9 24 20.9 1

Incoming CO2 line B from emitter 6 -1 10 17.1 1

Pump to loading facility line 7 -50 12 278 0.11

Liquefier to storage tanks line 7 -50 4 38 1

During the transfer of CO2 by piping different loss of containment scenarios can occur.

Table 5-10 summarizes the loss of containment scenarios for piping as prescribed by the MBRA.

Table 5-10: Initial failure frequency for piping

Scenario Failure frequency (per meter per year)

Piping 75<D<150 mm >150 mm

S3.a Rupture of a pipeline and ESD action 3.0*10-7

1.0*10-7

S3.b Rupture of a pipeline without ESD action 3.0*10-7

1.0*10-7


5.0*10-7

Table 5-11 till Table 5-15 will give detailed information about the scenarios that are modeled

within this study. The mass flow for the rupture scenarios in both tables is 1.5 x the mass flow

mentioned in Table 5-9. The factor 1.5 is used to take into account the increasing pump flow due

to the pipeline ruptures.

Table 5-11: Details of failure scenarios of the incoming CO2 line A from emitter Scenario Orifice

diameter

[inch]

Exit

velocity

[m/s]

Mass

rate

[kg/s]

Time[s] Failure

frequency

[1/ m yr]]

Time

fraction

in use [-]

Number

of meters

piping

Total failure

frequency

[1/yr]

S1.a 24 10.7 31.4 120 1.0 x 10-7

1 200 2.0 x 10-5

S1.b 24 10.7 31.4 1800 1.0 x 10-10

1 200 2.0 x 10-8

S2 2.4 284.5 1.4 1800 5.0 x 10-7

1 200 1.0 x 10-4

Table 5-12: Details of failure scenarios of the incoming CO2 line B from emitter Scenario Orifice

diameter

[inch]

Exit

velocity

[m/s]

Mass

rate

[kg/s]

Time[s] Failure

frequency

[1/ m yr]

Time

fraction

in use [-]

Number

of meters

piping

Total failure

frequency

[1/yr]

S1.a 10 50.6 25.7 120 1.0 x 10-7

1 200 2.0 x 10-5

S1.b 10 50.6 25.7 1800 1.0 x 10-10

1 200 2.0 x 10-8

S2 1 392 0.9 1800 5.0 x 10-7

1 200 1.0 x 10-4

Table 5-13: Details of failure scenarios of pump to loading facility line (during unloading) Scenario Orifice

diameter

[inch]

Exit

velocity

[m/s]

Mass

rate

[kg/s]

Time[s] Failure

frequency

[1/ m yr]

Time

fraction

in use [-]

Number

of meters

piping

Total failure

frequency

[1/yr]

S1.a 12 4.8 417 120 1.0 x 10-7

0.11 135 1.5 x 10-6

S1.b 12 4.8 417 1800 1.0 x 10-10

0.11 135 1.5 x 10-9

S2 1.2 116 18.4 1800 5.0 x 10-7

0.11 135 7.7 x 10-6

DET NORSKE VERITAS


MANAGING RISK




Table 5-14: Details of failure scenarios of pump to loading facility line (no unloading

activities) Scenario Orifice

diameter

[inch]

Exit

velocity

[m/s]

Mass

rate

[kg/s]

Time[s] Failure

frequency

[1/ m yr]

Time

fraction

in use [-]

Number

of meters

piping

Total failure

frequency

[1/yr]

S1.a 12 116 600 19 1.0 x 10-7

0.89 135 1.2 x 10-5

S2 1.2 116 18.4 628 5.0 x 10-7

0.89 135 6.0 x 10-5

Table 5-15: Details of failure scenarios of liquefier to storage tanks line Scenario Orifice

diameter

[inch]

Exit

velocity

[m/s]

Mass

rate

[kg/s]

Time[s] Failure

frequency

[1/ m yr]

Time

fraction

in use [-]

Number

of meters

piping

Total failure

frequency

[1/yr]

S1.a 4 9.1 57 120 1.0 x 10-7

1 140 1.4 x 10-5

S1.b 4 9.1 57 1800 1.0 x 10-10

1 140 1.4 x 10-8

S2 0.4 1800 5.0 x 10-7

1 140 7.0 x 10-5

5.1.5 Liquefaction unit

CO2 gas from the capture unit is liquefied in the liquefaction unit. The liquefaction unit consists

of a compressor, a heat exchanger and a cold box. This section gives more detailed information

about the configuration and loss of containment scenarios that can occur with the equipment in

the liquefaction unit.

5.1.5.1 Compressor

First the low pressure CO2 is compressed from 1 to 80 barg with a six stage compressor. Each

compressors stage is modeled as a separate compressor. The failure cases that are modeled for the

compressor are listed in Table 5-16.

Table 5-16: Initial failure frequency for compressors


Centrifugal compressor

S1.a Rupture of compressor and ESD action 5.0*10-5

S1.b Rupture of compressor without ESD action 5.0*10-8

S2 leakage of compressor hole with 10% of the diameter of the connection line 1.0*10-3


The mass flow for the rupture scenarios in the tables is 1.5 x the mass flow. The factor 1.5 is used

to take into account the increasing pump flow due to the pipeline ruptures.

DET NORSKE VERITAS


MANAGING RISK




Table 5-17: Details of failure scenarios of the compressors

Number

of stages

Scenario Orifice

diameter

[inch]

Exit

velocit

y [m/s]

Mass

rate

[kg/s]

Time[s] Failure

frequency per

stage [1/yr]

Time

fraction

in use [-]

Total failure

frequency

[1/yr]

6 S1.a 24 0.3 57 120 5.0 x 10-5

1 3.0 x 10-4

6 S1.b 24 0.3 57 1800 5.0 x 10-8

1 3.0 x 10-7

6 S2 2.4 0.3 57 1800 1.0 x 10-3

1 6.0 x 10-3

5.1.5.2 Heat exchanger

Due to the compression of the CO2 the temperature will increase. A decrease of the temperature

will be accomplished by cooling the CO2 with surface water in a heat exchanger. The failure

cases that are modeled for the heat exchanger are listed in Table 5-18.

Table 5-18: Initial failure frequency for a heat exchanger


Shell side condenser

S1.a Rupture of shell side heat exchanger and ESD action 5.0*10-5

S1.b Rupture of shell side heat exchanger without ESD action 5.0*10-8

S2 Release of total volume of heat exchanger in 10 minutes 5.0*10-5

S3 leakage of heat exchanger with 10 mm hole 1.0*10-3

Table 5-19: Details of failure scenarios of the Liquefaction unit

Scenario Orifice

diameter

[inch]

Volume

released [m3]

Exit velocity

[m/s]

Mass rate

[kg/s]

Time

[s]

Total failure

frequency [1/yr]

S1.a 24 1 19.6 57 120 5.0 x 10-5

S1.b 24 1 19.6 57 1800 5.0 x 10-8

S2 1 348 0.03 600 5.0 x 10-5

S3 0.4 1 348 4.9 1800 1.0 x 10-3

5.1.5.3 Cold box

The liquefaction process takes place at low temperatures. Thermal insulation is used to minimize

temperature losses due to heat transfer from equipment to the surrounding. The cold box provides

the thermal isolation of the equipment. The main equipments that are present in the cold box are

heat exchangers, separation pressure vessels and associated piping.

The height of the cold box is 10 meter. On the top it is equipped with a 24 inch vent to prevent

overpressures in case a loss of containment from equipment in the cold box occurs. The total

volume of gas and liquid of the equipment in the cold box is 90 and 35 m3 respectively. More

detailed information on the cold box is not available from the vendor. It is assumed that there is

100 meters of piping in the cold box. Half of the piping will contain vapor and the other half will

contain liquid. It is also assumed that most of the volume is present in the heat exchangers and

the volume in the separation vessels is negligible. The cold box will contain several small plate

DET NORSKE VERITAS


MANAGING RISK




fin heat exchangers which are modeled as a large heat exchanger. The process conditions of the

cold box are summed in Table 5-20.

Table 5-20: Characteristic of the cold box

Heat exchanger

Vapor CO2 will flow with a mass flow of 38 kg/s through a plate fin heat exchanger where it will

be liquefied. The liquefied CO2 will leave the heat exchanger with the same mass flow. In the

heat exchanger different loss of containment scenarios can occur. Table 5-21 summarizes the loss

of containment scenarios that can occur with a heat exchanger as prescribed by the MBRA.

Table 5-21: Initial failure frequency for plate-fin heat exchangers


Shell side heat exchanger





Table 5-22: Details of failure scenarios of the Liquefaction unit Scenario Orifice

diameter

[inch]

Volume

released

[m3]

Release

height

[m]

Exit velocity

[m/s]

Mass rate

[kg/s]

Time[s] Total failure

frequency

[1/yr]

Vapour

S1.a 24 5330 10 19.6 57 120 5.0 x 10-5

S1.b 24 69300 10 19.6 57 1800 5.0 x 10-8

S2 754 10 0.4 1.3 600 5.0 x 10-5

S3 0.4 3060 10 226 0.2 1800 1.0 x 10-3

Liquid

S1.a 24 29100 10 19.6 57 120 5.0 x 10-5

S1.b 24 93100 10 19.6 57 1800 5.0 x 10-8

S2 24500 10 0.1 40.8 600 5.0 x 10-5

S3 0.4 3564 10 117 2 1800 1.0 x 10-3

Equipment in cold box Phase Pressure [bar] Temperature [°C] Volume [m3]

Heat exchanger Liquid 7 -70 20.4

Heat exchanger Vapor 7 -20 75.4

Piping Liquid 7 -70 14.6

Piping Vapor 7 -20 14.6

DET NORSKE VERITAS


MANAGING RISK




5.1.6 Background data

The weather, population and other background data that are used to calculate the consequences

and risk results are explained in more detail in the following paragraph.

5.1.6.1 Weather data

The distribution of the wind direction, wind speed and the atmospheric stability were taken from

the nearest weather station which is the Eindhoven weather station. The weather is categorized

into various classes denominated by a letter (A to F) representing stability (“A” being very

unstable and “F” being very stable) and a number (1.5 – 5) representing wind speeds in m/s. The

meteorological situation D5 signifies stability class D and a wind speed of 5 m/s. In general the

largest effect distance for toxic substances is found with stable weather, in other words weather

class F1.5 (stability class F and a wind speed of 1.5 m/s

5.1.6.2 Surface roughness

The software tool Safeti-NL does not take into account the effect of obstacles on the dispersion of

a cloud. However, the surface roughness is a parameter which can be adjusted and it is an

(artificial) measurement of length that indicates the impact of the surrounding area on wind

speed. The default surface roughness length of 0.3 meters was taken for the calculations.

5.1.6.3 Population data

The largest effect distance at which a

fatality can occur is caused by the

release of the entire volume of a

storage tank in 10 minutes. The area

within a fatality could occur contains a

radius of 540 from the location of the

storage tanks. This area is visualized in

Figure 5-3. From this figure is seen that

there exist no other industrial or

residential activities other then the

emitter and CO2 terminal itself.

Therefore no population is taken into

account.

Figure 5-3: Largest distance at which a fatality can

occur

DET NORSKE VERITAS


MANAGING RISK




5.2 Consequence assessment

The next paragraphs will show the consequences for some loss of containment scenario for the

storage tanks and cold box. For the different LOC scenarios the maximum concentration profile

has been calculated as well as the lethality footprint.

The maximum concentration profile shows a side view of the maximum concentration distances.

For all scenarios three concentrations are displayed: the alarm value, the 1% lethality and the

100% lethality concentration (see also Paragraph 2.1.2). It is important to note that the lethality

concentrations are derived from a 30 minutes exposure time and that the maximum concentration

distances are not sustained for such a long time.

Therefore, the lethality footprint is displayed containing the 1%, 10% and 100% lethality

contours. Safeti-NL calculates the lethality of a certain LOC scenario by calculating the dose at a

location and using the CO2 probit function. The dose is a combination of concentration and

exposure time. The lethality contours are always smaller than the maximum lethal concentration.

The consequence assessment will only look at the effects of the different LOC scenarios (so

assuming it will happen) and does not take into account the probability of a LOC (is it likely to

happen).

5.2.1 Storage tank

After a storage tank is ruptured a CO2 cloud will be formed. The direction and speed at which the

cloud drifts away depends on the wind direction and wind speed. Figure 5-4 shows, for a F1.5

weather type, the drifted CO2 cloud when it reaches the maximum distance for dangerous CO2

concentrations. The dangerous concentrations (50,000 ppm) can reach up to 402 meters of the

release location.

After 80 seconds the CO2 cloud is diluted such that no dangerous concentration is present. The

distance where the alarm value concentration reaches its maximum value equals 800 meter. This

effect distance is reached 2 minutes after the initial rupture. Figure 5-5 shows the drifted CO2

cloud after 2 minutes.

The lethal footprint in Figure 5-6 shows that the maximum diameter of the cloud at which

fatalities can occur is 280 meters.

DET NORSKE VERITAS


MANAGING RISK




Figure 5-4: Side view of drifted CO2 cloud for a tank rupture after 64 seconds


DET NORSKE VERITAS


MANAGING RISK




Figure 5-6: Lethality footprint for a tank rupture

The scenario that will results in the largest effect distance is the release of the entire volume of

the storage tank in 10 minutes. The dangerous concentration (50,000 ppm) and alarm value

concentration for this scenario are visualized in Figure 5-7. It is found that the dangerous

concentration reaches up to 540 meter of the release location.

Figure 5-7: Side view of CO2 cloud for a release of the entire storage volume in 10 minutes

DET NORSKE VERITAS


MANAGING RISK




Figure 5-8 shows the interesting concentration of CO2 for a 10 mm leakage of the storage tank.

The dangerous concentrations (50,000 ppm) reaches not further than 9.5 meters of the release

location.

Figure 5-8: Side view of maximum concentration of 10 mm leakage of storage tank

5.2.2 Cold box

CO2 will be release in the hull of the cold box when there is a leak or rupture of equipment in the

cold box. The released CO2 can only leave the cold box by a 24 inch vent that is placed on top of

box. A vapor release due to a LOC in the cold box will increase the pressure in the cold box. If

the pressure increases further than the set point of the pressure safety valve, pressurized vapor

will be discharged through the vent to the atmosphere. Figure 5-9 shows the side view of the

discharged concentration via the vent in case of a vapor line rupture. Dangerous concentrations

will not occur at ground level.

DET NORSKE VERITAS


MANAGING RISK




Figure 5-9: Release of vapor by the vent of the cold box

During a LOC of liquid pressurized CO2 the discharge temperature will decrease to approx. -80°

C, due to the expansion of CO2 to atmospheric pressure. At atmospheric pressure and -80° C the

phase of CO2 is solid and dry ice will be formed. The ice particle will have a downwards

movement due to the higher density then the air in the cold box. The thermodynamic theory

determines that CO2 cannot exist in the liquid phase at atmospheric pressure. At atmospheric

pressure CO2 will be either in the vapor phase or exist as a two phase mixture of vapor and solid

phase CO2. The formed dry ice sublimates at atmospheric pressure directly into vapor. The vapor

will be discharged through the vent to the atmosphere. The vapor release will show the same

behavior as seen in Figure 5-9.

DET NORSKE VERITAS


MANAGING RISK




5.3 Risk result & risk assessment

Figure 5-10 displays the individual risk contours for the CO2 terminal. The maximum calculated

individual risk outside the terminal boundary is in the order of 10-5

/year or less and is located

near the liquefier and the jetty area. In this area no vulnerable objects, such as housing, should be

present and this is also not the case. The 10-7

/year and 10-8

/year individual risk contours reach

further outside the plant boundary. However, no legislation restrictions are related to these risk

levels.

Figure 5-10: Individual risk CO2 terminal at emitter

The outdoor individual risk at which people are exposed at the office location inside the plant

boundary is given in Table 5-23. Most of the risk is caused by the rupture of the storage tanks.

Table 5-23: Risk contributors at the office location

Scenario Risk [1/yr] Contribution to total risk [%]

Rupture tank 1 1.0 x 10-7

44.9


38.0

10 minutes outflow tank 1 1.9 x 10-8

8.0


8.0

Rupture loading arm 1.8 x 10-9

0.8

Rupture loading pump 7.6 x 10-10

0.3

DET NORSKE VERITAS


MANAGING RISK




The outdoor individual risk at which people are exposed at the public road outside the plant

boundary, west of the terminal is given in Table 5-24. Most of the risk is caused by the outflow of

the entire volume of a storage tank in 10 minutes.

Table 5-24: Risk contributors at the public road



32.1


32.1


19.6


16.2

The risk caused by the CO2 terminal does not reach the external population located outside the

plant boundary. Therefore the calculation of societal risk is not required.

5.3.1 Conclusion risk results

In this chapter the individual risk has been calculated for the CO2 terminal on the location of the

emitter. The individual risk calculations for the terminal generated a maximum individual risk

outside the terminal in the order of 10-5

/year or less. The area that is exposed to these contours

does not contain other industrial and residential activities therefore these results do not conflict

with regulatory requirements.

DET NORSKE VERITAS


MANAGING RISK




6 TRANSPORT OF CO2 BY BARGE

6.1 Introduction

Besides transport via pipelines, it is foreseen to transport CO2 by special designed inland barges

from the different inland CO2 sources to the CO2 terminal location in the Port of Rotterdam. The

CO2 will be transported in liquid phase because liquid CO2 has got a higher density than gaseous

CO2, which means that more CO2 can be transported at one time.

The safety study will consider the CO2 transport from emitter E to the CO2 terminal located in the

Port of Rotterdam. The barges will transport the CO2 at a temperature of -50°C and a pressure of

7 barg. The barges have a transport capacity of 4000 ton each. The annual number of barge

movements is 250 to transport the 1 MTA from the emitter to the Port of Rotterdam.

Figure 6-1 depicts the shipping route from emitter E to the CO2 terminal located in the Port of

Rotterdam. The barges depart from emitter E and follow partly the river Maas, the Maas-Waal

channel, the Waal, the Boven-Merwede, the Oude-Maas, the Hartelkanaal and finally arrive at the

Beerkanaal (Maasvlakte) in the Port of Rotterdam.

Figure 6-1: Shipping route from emitter E to the Port of Rotterdam

The CO2 transported on the water could pose an external risk due to collision scenarios or an

accidental release from the above-deck piping of the barge. In this chapter the consequences and

risks of the barge shipping activities will be calculated and evaluated.

The safety study focuses on Nijmegen and Dordrecht as possible release location for the barges,

but the complete shipping route will be evaluated.

DET NORSKE VERITAS


MANAGING RISK




6.2 Scenarios

Accident scenarios of barges in transit consist out of LOC scenarios due to internal failure (e.g.

leak of piping) or due to external failure (e.g. collision).

The first group includes aspects like mechanical failure, material/construction errors,

fire/explosions, failure of cooling system etc. which are not waterway related. Collision accidents

on the other hand are related to a waterway.

The safety study will assess four possible LOC scenarios for the barges. A small (3 inch) and

large leak (6 inch) due to a collision with another barge and a small (150 mm) and large leak (800

mm) due to a collision with a seagoing vessel. The reason of the larger leak sizes for a collision

with a seagoing vessel is that seagoing vessels, sailing with the same speed as a barge, have more

kinetic energy due to the higher mass. In Table 6-1 the LOC scenarios are listed. These were

taken from the Protocol Risicoanalyse zee- en binnenvaart [Ref 21].

Table 6-1: Scenarios for barges

Barge - Barge collision Barge - Seagoing vessel collision

1. Leak with a diameter of 3 inch (~75 mm) Leak with a diameter of 150 mm

2. Leak with a diameter of 6 inch (~150 mm) Leak with a diameter of 800 mm

6.2.1 Modeling LOC scenarios of barges and seagoing vessels

The leak scenarios have been modeled with a leak model in Safeti-NL. The LOC scenarios have

been modeled with a release height of 1 meter and a horizontal release direction.

All the effect distances of the scenarios have been calculated with a weather type F1.5 (steady

atmosphere, low wind speeds), which is the most conservative for toxic scenarios, and D5

(normal atmosphere, higher wind speeds).

6.2.1.1 Modeling of a LOC scenarios of liquid CO2

The leak scenarios have been modeled with a pressure of 7 bara and a temperature of -50 ºC.

Under these conditions the CO2 is in liquid phase and solid (ice) formation will take place when a

LOC scenario occurs (see also paragraph 2.1.4.2).

The LOC scenario of a tank will firstly drain liquid CO2 until the liquid CO2 level is lowered to

the release height of the tank. At that moment, the tank will depressurize, the remaining liquid

CO2 in the tank starts evaporating and only vapor CO2 will be released through the leak. The

liquid CO2 in the tank will cool down due to the evaporation of the CO2. When the liquid CO2

cools down to −78 °C all the remaining CO2 will instantly turn into solid CO2. It is assumed in

the calculations that 2/3 (67%) of the inventory of the tank (50% liquid and 17% vapour) will be

released before the remaining CO2 turns into solid CO2. This is based on the assumption that the

leak of the tank is located at half the tank height and part of the CO2 has to be evaporated to cool

down the remaining liquid CO2.

Part of the released liquid CO2 will “rain” out from the CO2 jet as solid CO2 and sublimates from

the water. This sublimation will cause locally, at the release location, a higher CO2 concentration.

DET NORSKE VERITAS


MANAGING RISK




However, the influence of the sublimating CO2 is negligible compared to the release of gaseous

CO2. Therefore, this effect is not considered for horizontal releases and it is assumed that all the

CO2 will be released as vapor. This is a conservative assumption and the calculated effect is as a

result larger than in reality.


The next paragraphs will show and explain the effects of a LOC of the barges. For each LOC

scenario the maximum concentration profile has been calculated as well as the lethality footprint.






Therefore, the lethality footprint is calculated. Safeti-NL calculates the lethality of a certain LOC

scenario by calculating the dose at a location and using the CO2 probit function. The dose is a

combination of concentration and exposure time. The lethality contours are always smaller than

the maximum lethal concentration.



happen).

6.3.1 LOC scenarios of a barge – barge collision

The figures below show the consequences of a small and large leak of a CO2 barge due to a

collision with another barge.

Figure 6-2 shows the maximum concentration footprint of a small leak (3 inch) at one of the

tanks of the barge. The CO2 jet is directed horizontally and dangerous CO2 concentrations

(50,000 ppm, brown line) can reach up to 120 meters of the release location (120 meters for D5).

The lethality footprint calculations confirm the distance found in Figure 6-2. The maximum

distance from the release location at which fatalities can occur is at around 107 meters (102

meters for D5) from the CO2 barge.

It is important to note that these lethality distances are calculated at a height of 1 meter and that

Safeti-NL does not take into account obstacles or barriers. The shore height is higher than 1

meter, which means that the lethality distances are in reality smaller.

DET NORSKE VERITAS


MANAGING RISK




Figure 6-2: Concentration profile of a small leak (3 inch)

Figure 6-3 shows the maximum concentration footprint of a large leak (6 inch) at one of the tanks

of the barge. The CO2 jet is directed horizontally and dangerous CO2 concentrations (50,000

ppm, brown line) can reach up to 230 meters of the release location (260 meters for D5).

Figure 6-3: Concentration profile of a large leak (6 inch)

DET NORSKE VERITAS


MANAGING RISK










6.3.2 LOC scenarios of a barge – seagoing vessel collision

The figures below show the consequences of a small and large leak of a CO2 barge due to a

collision with a seagoing vessel.

Figure 6-4 shows the maximum concentration footprint of a small leak (150 mm) at one of the



Figure 6-4: Concentration profile of a small leak (150 mm)




DET NORSKE VERITAS


MANAGING RISK







Figure 6-5 shows the maximum concentration footprint of a large leak (800 mm) at one of the



Figure 6-5: Concentration profile of a large leak (800 mm)







6.3.3 Conclusion consequence results

In this section the consequences, concentration and lethality have been calculated of several LOC

scenarios of the CO2 barges:

The 1% lethality range of a 3 inch leak at one of the tanks of a barge is 107 meters.

The 1% lethality range of a 6 inch / 150 mm leak at one of the tanks of a barge is 225 meters.

The 1% lethality range of an 800 mm leak at one of the tanks of a barge is 510 meters.

DET NORSKE VERITAS


MANAGING RISK




The barges carrying CO2 could be located at any place of the shipping lane when a leak occurs.

This means that dangerous CO2 concentrations can reach the shore due to a leak at the barge and

fatalities can occur. In the next section a risk analysis is performed to asses whether the risk is

acceptable.


To assess the risk of the CO2 barges with respect to onshore populations two locations have been

chosen: Nijmegen and Dordrecht. The waterway used by the CO2 barge runs directly through

these towns and these are the two locations where (dense) populations are nearest to the CO2

barge when it passes. As such these two locations represent the most critical route segments.

Dutch regulations prescribe that no vulnerable object (e.g. house) may be present in 10-6

per year

individual risk contour created by the barge.

The vessel intensities are based on public available information and the distribution of the small

and large leak scenarios is based on the Protocol Risicoanalyse zee- en binnenvaart [Ref. 21].

6.4.1 Individual risk

For the collision frequency causing a large damage (not necessarily resulting in a spill/LOC) the

generic frequency of 1.4 x 10-6

/vessel km [Ref. 26] was used. The Purple Book [Ref. 26] also

provides the probability of a spill/LOC scenario following a collision.

In Nijmegen a probability for a small leak (3 inch) of 0.025 and for a large leak (6 inches) is

0.00012 has been found

In Dordrecht it has been assumed that 50% of the collisions are caused by a barge and the

other 50% are caused by a seagoing vessel resulting in a probability for a small leak (3 inch)

of 0.0125, for a 150 mm / 6 inch leak of 0.01256 and a probability of a large leak (800 mm)

of 0.00006.

Figure 6-6 presents the individual risk near Nijmegen caused by the transportation of CO2. The

risk calculations generate a maximum individual risk of 10-8

per year (red contour) and therefore

the criterion that no vulnerable object is present within the 10-6

contour is not breached.

DET NORSKE VERITAS


MANAGING RISK




Figure 6-6: Individual risk Nijmegen

Figure 6-7 on the next page presents the individual risk near Dordrecht caused by the

transportation of CO2. Also here the risk calculations generate a maximum individual risk of 10-8

per year (red contour and therefore the criterion that no vulnerable object is present within the 10-

6 contour is not breached.

Based on the fact that these two location represent the most critical segments in the waterway and

the fact that the risk does not exceed the criterion it can be concluded that all along the route the

individual risk from the CO2 barge will not result in a breach of the 10-6

criterion.

DET NORSKE VERITAS


MANAGING RISK




Figure 6-7: Individual risk Dordrecht

6.4.2 Societal risk

The societal risk for the transport of CO2 by barge has not been calculated for the different

waterway sections because the calculated individual risk is very low. The 10-8

individual risk

contour only just reaches the shoreline in some locations. As such it can be concluded that

societal risk will be negligible.


The individual risk caused by the CO2 barges at the used waterway sections is in the range of 10-8

per year and therefore the criterion that no vulnerable object is present within the 10-6

contour is

not breached. As the 10-8

contour barely reaches shore it can also be concluded that societal risk

will be negligible.

DET NORSKE VERITAS


MANAGING RISK




7 TRANSPORT OF CO2 BY PIPELINE (LOW PRESSURE)

7.1 Introduction

The CO2 sources located in the Port of Rotterdam will be connected to the CO2 terminal by a low

pressure pipeline network. Each emitter will tie-in via an aboveground pipeline into the network,

which is located in a dedicated pipeline route, the so-called “buisleidingenstraat”. The pipelines

in the buisleidingenstraat are located underground and waterway crossing are done via

underground tunnels or horizontal directional drilled (HDD) pipelines. At the CO2 terminal the

pipeline will go aboveground to connect to the terminal infrastructure. Figure 7-1 depicts the

routing of the low pressure pipeline network.

Figure 7-1: Route low pressure pipeline

The total length of the main pipeline is approx. 31.5 kilometers and the diameter is 20 inch (~50

cm). The operating condition of the pipeline is 34.5 bara (inlet) and the temperature is around 10

ºC. The normal annual flow in the main pipeline is around 1.2 Mtons, which is about 39 kg/s.

7.2 LOC scenarios and frequencies

Transport pipelines can fail due to internal causes (e.g. corrosion, pressure above design pressure)

and due to external interference (e.g. groundwork). The safety study will assess two possible

LOC scenarios: a rupture of the pipeline and a leak of the pipeline. In Table 7-1 and Table 7-2 the

LOC scenarios and their corresponding frequencies are listed for underground and aboveground

pipelines and which were taken from the Reference Manual Bevi Risk Assessments (MBRA).

DET NORSKE VERITAS


MANAGING RISK




Table 7-1: LOC scenarios for underground transport pipelines

Frequency

(per meter per annum)

Pipeline in pipe bay

Frequency


Pipeline complies with

NEN 3650

Frequency


Other pipelines

1. Rupture in the pipe 7 × 10-9

1.525 × 10-7

5 × 10-7

2. Leak with a diameter of

20 mm 6.3 × 10

-8 4.575 × 10

-7 1.5 × 10

-6

Table 7-2: LOC scenarios for aboveground pipelines

Frequency


nominal diameter < 75

mm

Frequency


75 mm ≥ nominal

diameter ≤ 150 mm

Frequency


nominal diameter > 150

mm


3 × 10-7

1 × 10-7

2. Leak with an effective

diameter of 10% of the

nominal diameter, up to a

maximum of 50 mm

5 × 10-6

2 × 10

-6

5 × 10-7

Underground pipelines can have different additional safety measures, both technical and

organizational, which will influence the failure frequencies. For this reason three different failure

frequencies can be used for underground pipelines. For aboveground pipelines the failure

frequencies for pipelines with a larger diameter are lower than pipelines with smaller diameter

since these can better withstand external impacts. The failure frequencies for underground

pipelines are lower than for aboveground pipelines because underground pipelines are more

protected against external impact.

Some parts of the pipeline are located in tunnels to cross the waterways Oude Maas and

Calandkanaal. In the risk analysis for a CO2 storage initiative in Barendrecht [Ref 3], a failure

frequency was derived for a CO2 pipeline in a tunnel. This failure frequency is lower than the

failure frequency for a pipeline in a pipe bay (dedicated pipeline route), based partly on the

assumptions that external interference could be excluded. However, in a response to questions

from the Environmental Protection Agency Rijnmond (DCMR), RIVM answered in a letter that

some of the assumptions for the derived failure were not correct or not sufficiently based [Ref 4].

Therefore, the failure frequency for pipelines in a pipe bay will also be used for the pipeline

segments in the tunnels, which are as well part of the dedicated pipeline route.

7.3 Modeling pipeline LOC scenarios

The modeling of the LOC scenarios differs for the pipeline rupture compared to the leak

scenarios, as well as whether the pipeline is located underground, aboveground or in a tunnel.

The pipeline rupture scenarios have been modeled with the “long pipeline” model in Safeti-

NL which means that the 2-sided outflow during a pipeline rupture is considered in the

calculations. During normal operation the pressure in the pipeline decreases due too internal

friction. As a result the discharge upon a rupture will vary depending on where the pipeline

DET NORSKE VERITAS


MANAGING RISK




ruptures. To take this into account, the pipeline rupture scenario is modeled with 5

consecutive pipeline segments, each having their own (decreasing) pressure setting resulting

in a different discharge.

The leak and rupture scenarios have been modeled with the maximum inlet pressure of 34.5

bara.

The underground pipeline scenarios have been modeled with a release height of 0 meter and a

vertical release direction. It is expected that a crater will be formed during the release and that

there is no loss of momentum of the CO2 jet. The aboveground scenarios have been modeled

with a release height of 1 meter and a horizontal release direction. These assumptions are all

according to MBRA.

The Dutch guidelines are not specific on how to model LOC scenarios of pipelines located under

waterways or in tunnels.

The pipeline crossings under the Dintelhaven and Hartelkanaal will be done via HDD or the

Direct Pipe method and located at a depth of around 20-30 meters. A LOC of a pipeline at

such depth will lose momentum and this should be taken into account.

In case of a gas release underwater a bubble plume will form (see Figure 7-2). This bubble

plume will decrease the release velocity and prevent jet dispersion. This risk analyses

assumes a surface diameter of the bubble plume of 30% of the pipeline depth, based on the

guideline for risk analysis from the international Association of Oil and Gas Producers (OGP)

[Ref 22] and the research

done by the Petroleumtilsynet

for Norpipe [Ref 23].

The OGP guideline calculates

a surface diameter of the

bubble plume of 20% of the

pipeline depth. However,

because for a CO2 release a

low release velocity will

result in larger effects the

conservative diameter of 30%

was used, based on the

analyses done by the

Petroleumtilsynet [Ref 23].

The CO2 velocity at the

surface was determined with

the release rate and surface

area of the plume. The CO2

temperature, to calculate the

density, was assumed equal as

the water temperature due to

the intense mixing with the

water during the release.

The dissolving of CO2 in the water is not considered in the calculations, which is a

conservative assumption.

Figure 7-2: Steady-state bubble plumes with surface flow

[Ref 23]

DET NORSKE VERITAS


MANAGING RISK




For the pipeline sections located in one of the tunnels, the same approach has been used as in

the risk analysis for the Barendrecht initiative [Ref 3].

A pipeline rupture in one of the tunnels will lead to a quick pressure increase in the tunnels.

The tunnel exists of the Botlek (Oude Maas) and Calandkanaal tunnel are closed with steel

shutters. It is expected that the steel shutters will be blown away due to the quick pressure

increase in the tunnel. The CO2 release will lose part of its momentum in the tunnel and the

release velocity will be lower at the tunnel exits. Safeti-NL does not provide a specific model

for LOC scenarios in tunnels. Therefore the pipeline rupture in the tunnels will be modeled as

a vertical release with low release velocity at the tunnel exits. The release velocity at the

tunnel exits have been calculated by dividing the volume flow of the 5 discharge segments by

the tunnel exit area. It is expected that only a pipeline rupture will lead to a failure of the steel

shutters. Therefore a pipeline leak in the tunnels is not considered in the consequence and risk

assessment.





Appendix 1 shows and explains the effects of different LOC scenarios from a low pressure

pipeline: aboveground, underground, at a waterway crossing and in a tunnel. For each LOC

scenario the maximum concentration profile has been calculated and for most scenarios also the

lethality footprint.












happen).

Table 7-3 summarizes the results of Appendix 1. It shows the effect distances for the different LP

scenarios.

DET NORSKE VERITAS


MANAGING RISK




Table 7-3: Effect distances LP pipeline scenarios

Location Scenario Distance 50,000 ppm (m) Distance 1% lethality (m)

F1.5 D5 F1.5 D5

Aboveground Rupture 140 130 90 83

Leak 17 15.5 15.5 14

Underground Rupture <1.5 <1.5 <1.5 <1.5

Leak <0.5 <0.5 <0.5 <0.5

Tunnel Rupture 420 245 370 135

Waterway crossing Rupture 440 186 380 155

Leak 22 14 <1 <1


In this section the consequences, concentration and lethality, have been calculated for different

LOC scenarios of a low pressure pipeline: aboveground, underground, crossing a waterway and

tunnel pipeline.

Dangerous CO2 concentrations (50,000 ppm) at ground level due to a LOC of an underground

pipeline are minor because the CO2 jet is directed vertically and the CO2 concentration is

quickly diluted before reaching the ground again.

Dangerous CO2 concentrations (50,000 ppm) at ground level due to a LOC of an

aboveground pipeline can reach up to 140 meters and the 1% lethality contour reaches 90

meters.

Although the release of a LOC of a pipeline in a tunnel or crossing a waterway is directed

vertically, as for the underground pipeline, dangerous CO2 concentrations (50,000 ppm) at

ground level can reach up to 420 meters for a pipeline in a tunnel and 440 meters for a

waterway crossing. This is caused by the loss of momentum of the jet which lowers the air

entrainment and thereby lowers the dilution of CO2. The 1% lethality contour for a pipeline in

a tunnel reaches 370 meters and 380 meters for a waterway crossing.

DET NORSKE VERITAS


MANAGING RISK




7.5 Risk assessment

The risk calculations combine the consequences with the frequencies of each LOC scenario. The

next paragraphs show the risk results of the different low pressure pipeline sections, located

underground, crossing the waterways Dintelhaven / Hartelkanaal and located in the Botlek /

Calandkanaal tunnel. The aboveground pipeline risk calculations should be integrated in the

terminal QRA because the pipeline will come aboveground at the CO2 terminal site and is

therefore not considered in this safety study.


The risk calculations use weather and population data to calculate the individual and societal risk.

Weather data


the Rotterdam weather station. These data are considered to be representative for the complete

route.

Surface roughness





Population data

The Dienst Centraal Milieubeheer Rijnmond (DCMR) provided the population file for the

Rotterdam region which was used for the societal risk calculations. In the calculations for the

societal risk is assumed that the population inside a building is more protected. In accordance

with MBRA a factor of 0.1 was used to take this into account.

7.5.2 Risk results underground pipeline

The consequences of an LOC of an underground pipeline are minor because the CO2 jet is

directed vertically and the CO2 concentration is quickly diluted before reaching the ground again.

Hazardous CO2 concentrations occur only directly above the release location. Safeti-NL does not

calculate any risk contours due to the low effect distances of a LOC. This means that the risk

contour is actually a line following the pipeline trajectory.

DET NORSKE VERITAS


MANAGING RISK




7.5.3 Risk results Botlek tunnel

The individual risk contours for the pipeline segment in the Botlek tunnel is in the order of 10-

7/year or less and is thereby lower than the maximum acceptable individual risk criteria of 10

-

6/year.

Figure 7-3: Societal risk Botlek tunnel

Figure 7-3 shows the calculated societal risk (blue line) for the pipeline segment inside the Botlek

tunnel. The red line represents the maximum group risk criteria: the calculated societal risk is

below the target criteria.

DET NORSKE VERITAS


MANAGING RISK




7.5.4 Risk results Calandkanaal tunnel

The individual risk contours for the pipeline segment in the Calandkanaal tunnel is in the order of

10-7

/year or less and is thereby lower than the maximum acceptable individual risk criteria of 10-

6/year.

Figure 7-4: Societal risk Calandkanaal tunnel

Figure 7-4 shows the calculated societal risk (blue line) for the pipeline segment inside the

Calandkanaal tunnel. The red line represents the maximum group risk criteria: the calculated

societal risk is below the target criteria and stops before the 200 fatalities.

DET NORSKE VERITAS


MANAGING RISK




7.5.5 Risk results Dintelhaven crossing

The individual risk contours for the pipeline segment crossing the Dintelhaven is in the order of

10-7


6/year.

Figure 7-5: Societal risk Dintelhaven crossing

Figure 7-5 shows the calculated societal risk (blue line) for the pipeline segment crossing the

Dintelhaven. The red line represents the maximum group risk criteria: the calculated societal risk

is below the target criteria.

DET NORSKE VERITAS


MANAGING RISK




7.5.6 Risk results Hartelkanaal crossing

The individual risk contours for the pipeline segment crossing the Hartelkanaal is in the order of

10-7


6/year.

Figure 7-6: Societal risk Hartelkanaal crossing

Figure 7-6 shows the calculated societal risk (blue line) for the pipeline segment crossing the

Hartelkanaal. The red line represents the maximum group risk criteria: the calculated societal risk

is below the target criteria.


In this section the individual and societal risk have been calculated for the different low pressure

pipeline segments. The risk calculations for the underground pipeline did not generate risk

contours or FN curves due to the low effect distances of an LOC. Besides the sections located

underground, the risk was calculated for the sections of the low pressure pipeline crossing the

waterways and located in the Botlek and Calandkanaal tunnel. For all sections the individual risk

is below the maximum acceptable individual risk criteria of 10-6

per year. The societal risk for all

the sections is below the target criteria.

DET NORSKE VERITAS


MANAGING RISK




7.6 Conclusion

In this chapter a safety assessment was made for the low pressure pipeline located in the

buisleidingenstraat. The consequence assessment calculated the effects of two LOC scenarios,

rupture and leak, for the pipeline. The calculations were done for the different possible locations

of the pipeline: aboveground, underground, crossing the waterway or in a tunnel.

A risk assessment was performed to calculate the risk of the pipeline and assess whether the risk

is acceptable or mitigation is needed. The section of the pipeline located aboveground is only

located at the site of the different emitters and at the CO2 terminal. Therefore, the risk of this part

of the pipeline is not considered in this safety study. The risk assessment calculated the risk of the

pipeline sections located in a tunnel (Botlek and Calandkanaal tunnel) and crossing a waterway

(Dintelhaven and Hartelkanaal). For all sections the individual risk is below the maximum

acceptable individual risk criteria of 10-6

per year. The societal risk for all the sections is below

the target criteria.

DET NORSKE VERITAS


MANAGING RISK




8 CO2 TERMINAL AT THE PORT OF ROTTERDAM

8.1 Introduction

The purpose of the CO2 terminal in the Port of Rotterdam is to receive, temporary store and

export CO2. The terminal will receive CO2 from the low pressure pipeline and from the barges.

The CO2 will be send-out via the high pressure pipeline and the seagoing vessels. The location of

the terminal is at the entrance of the second Maasvlakte at the intersection of the Yangtze, the

Alexia and the Ariana harbor. The potential location is shown in Figure 8-1.

.

Figure 8-1: Position of the CO2 terminal in the port of Rotterdam

This chapter identifies and assesses the consequences and risks of the different activities, such as

(un)loading and storage, of the CO2 terminal in the Port of Rotterdam.

DET NORSKE VERITAS


MANAGING RISK




Description of the terminal

The CO2 terminal will receive CO2 via land and water. Liquid CO2 will be received by the

terminal via barges while pressurized CO2 will be received at the terminal via incoming pipelines.

It is expected that yearly 250 barges will deliver liquid CO2 to the terminal. The liquid CO2 is

stored in four pressurized storage vessels.

Pressurized CO2 will enter the terminal via the low pressure pipeline network in the Port of

Rotterdam and emitter B. The pressurized CO2 will be liquefied in the liquefier. After the

liquefaction process 64% of the CO2 will be sent to the storage tanks and 36% will be sent to the

send-out pumps which pump the CO2 at 150 barg to an offshore location.

CO2 from the storage tank will be transferred to the loading facility where it is loaded into

carriers. An overview of the CO2 terminal is given in Figure 8-2.

Figure 8-2: Overview of the CO2 terminal

DET NORSKE VERITAS


MANAGING RISK




8.2 Scenarios

The next paragraphs will discuss and provide the characteristics of the different parts of

equipment located on the CO2 terminal. Besides the process conditions, the paragraph will

discuss the possible LOC scenarios that are considered.

8.2.1 Storage tanks

The terminal contains four identical pressurized storage tanks without a bund. Each storage tank

contains a volume of 10.000 m3. The CO2 is stored at a temperature of -50 °C at 7 bara.

During storage of pressurized liquid CO2, different loss of containment scenarios can occur.

Table 8-1 summarizes the loss of containment scenarios for pressures storage tanks as prescribed

by the MBRA.

Table 8-1: Failure frequencies for pressurized storage tanks


Pressured storage tank

Rupture of the storage tank 5*10-7

per year

Release of total volume of tank in 10 minutes 5*10-7

per year

Leakage of tank through 10 mm hole 1*10-5

per year

A BLEVE scenario is not taken into account because the storage conditions of the tanks are

outside the so called BLEVE envelope and there is no possibility of fire impingement since there

are no flammable materials onsite.

8.2.2 Shipping

A large part of the CO2 will be imported and exported via transport on water. It is assumed that

250 barges per year will deliver 1 Mtons of CO2 from the inland emitter to the terminal. The

imported CO2 will be stored in the storage vessels. From the storage vessels the liquid CO2 will

be shipped with seagoing vessels to an offshore location. It is assumed that yearly 96 seagoing

vessels visit the terminal to load CO2 and transport it to an offshore location.

The terminal will be equipped with a loading and unloading jetty to receive and send the liquid

CO2. The jetty for the unloading of CO2 from the barges consists of a 12 inch loading arm and an

8 inch vapor return arm. The liquid CO2 is unloaded from the barges with a mass flow of 1000

ton/hr. The vapor return arms are not modeled in this QRA because of the low amount of mass

that flows through the arms.

The jetty for the loading of CO2 to the seagoing vessels will consist of two 16 inch loading arms

and an 8 inch vapor return arm. CO2 will be loaded from the storage tanks into the seagoing

vessels with a mass flow of 2875 ton/hr.

Table 8-2 summarizes the characteristics of the loading activities.

DET NORSKE VERITAS


MANAGING RISK




Table 8-2: Characteristic of the loading activities

Jetty Number of

(un)loading activities

per yr

Number of

(un)loading hr

per activity

[hr]

hours of

(un)loading

activities per yr [hr]

diameter

[inch]

flow per loading

arm [kg/s]

1 96 12 1152 16 399

2 250 4 1000 12 278

During the loading and unloading of CO2 different loss of containment scenarios can occur. Table

8-3 summarizes the loss of containment scenarios for shipping and loading activities as

prescribed by the MBRA.

The CO2 terminal will be equipped with an automatic leak detection system which will

automatically activate the emergency shut down (ESD) valves. In case of a rupture of a pipeline

the automatic shutdown valves will be operated and the valve will be closed. The MBRA

prescribes that the probability of failure per operation of automatic shut down valves equals

0.001. The time to require closing the blocking valves equals 120 seconds. In case the closing of

the blocking valves will fail the duration of the outflow will be 1800 seconds.

The automatic shutdown system does not work for leakages because it is assumed that the gas

detection is not capable of detecting the small amount of gas that will be released in case of a

leakage.

Table 8-3: Failure frequencies for shipping and loading activities


(un)Loading of refrigerated gas tanker

S1.a Rupture of the loading arm and ESD action 2.7*10-8

per hr

S1.b Rupture of the loading arm without ESD action 3*10-11

per hr

S2 Leakage of the loading arm 3*10-7

per hr

S3 External impact from accidents involving the ship, large release

(126m3)

0.0015xf0

S4 External impact from accidents involving the ship, small release

(32m3)

0.006xf0

The terminals jetties are planned at the entrance of the second Maasvlakte at the intersection of

the Yangtze, the Alexia and the Ariana harbor. All ships that will enter the second Maasvlakte

will pass the jetties of the CO2 terminal. In 2008 Marin performed a study to forecast the number

of ships that will enter the harbor of Rotterdam in 2035 [Ref 24]. This prognosis is used to

estimate the number of ships that will pass the location of CO2 terminal. Table 8-4 shows the

number of ships that will pass the terminal. The forecast predict that in the year 2035 yearly

14149 ships will pass the terminal.

DET NORSKE VERITAS


MANAGING RISK




Table 8-4: Prognosis number of ship passing the terminal in 2035

Destination Number of ships/year

Euromax second Maasvlakte 1488

MV2 terminal West 2805

MV2 terminal mid-W 2771

MV2 terminal Mid-O 2302

MV2 terminal Oost 1454

MV2 chemieterminal 1611

Total 14149

The collision frequency of colliding ships into a moored ship is prescribed in the MBRA. The

MBRA prescribes that the frequency of a collision that will result in a large and small release is

0.0015 x f0 and 0.006 x f0 respectively. The f0 equals 6.7 x 10-11

x T x t x N. Where T is the

number of ships that will pass the terminal, t equals the time the ship is moored at the jetty and N

is the number of (un)loading activities.

Table 8-5 and Table 8-6 give detailed information about the scenarios that are modeled within

this study. The mass flow for the rupture scenarios in both tables is 1.5 x the mass flow

mentioned in Table 8-2 to take into account the increasing pump flow.

Table 8-5: Details of failure scenarios loading jetty

Number

of

loading

arm

Scenario Orifice

diameter

[inch]

Exit velocity

[m/s]

Mass

rate

[kg/s]

Time[s] Failure

frequency

per arm

[1/hr]

Failure

frequency

per arm

[1/yr]

Failure

frequency

per jetty

[1/yr]

2 S1.a 16 3.8 599 120 2.7 x 10-8

3.1 x 10-5

6.2 x 10-5

2 S1.b 16 3.8 599 1800 3.0 x 10-11

3.5 x10-6

6.9 x 10-8

2 S2 1.6 117 32.7 1800 3.0 x 10-7

3.5 x 10-4

6.9 x 10-4

2 S3 n/a 118 80.9 1800 n/a n/a. 1.6 x 10-7

2 S4 n/a 118 20.6 1800 n/a n/a 3.4 x 10-5

Table 8-6: Details of failure scenarios unloading jetty

Number

of

loading

arm

Scenario Orifice

diameter

[inch]

Exit velocity

[m/s]

Mass

rate

[kg/s]

Time[s] Failure

frequency

per arm

[1/hr]

Failure

frequency

per arm

[1/yr]

Failure

frequency

per jetty

[1/yr]

1 S1.a 12 4.8 417 120 2.7 x 10-8

2.7 x 10-5

2.7 x 10-5

1 S1.b 12 4.8 417 1800 3.0 x 10-9

3.0 x10-6

3.0 x 10-8

1 S2 1.2 117 18.4 1800 3.0 x 10-7

3.0 x 10-4

3.0 x 10-4

1 S3 n/a 118 80.9 1800 n/a n/a. 3.0 x 10-7

1 S4 n/a 118 20.6 1800 n/a n/a 3.4 x 10-5

DET NORSKE VERITAS


MANAGING RISK




8.2.3 Pumps

Liquefied CO2 is sent to the storage tanks or pumped to the send-out line where it will be

transported to an offshore gas field. The CO2 will be transported to the gas field with a pressure

of 150 barg. This send-out pressure is obtained with two centrifugal pumps. Each of the pumps

will have a mass flow of 48.6 kg/s.

From the storage tank liquid CO2 is pumped to the seagoing vessels with a centrifugal pump. The

pump will transfer the CO2 to the seagoing vessels with a mass flow of 799 kg/s. The

characteristic of the sent out and loading pump are given in Table 8-7.

Table 8-7: Characteristic of the pumps

Pump Pressure suction

line [bar]

Temperature

[°C]

Diameter suction

line [inch]

Mass flow rate

[kg/s]

Time fraction

in use [-]

Send-out pump 84 28 24 48.6 1

Loading pump

(operational) 7 -50 20 799 0.13

Loading pump (non

operational) 7 -50 20 0 0.87

During the pumping of CO2 different loss of containment scenarios can occur. Table 8-8

summarizes the loss of containment scenarios for pumping activities as prescribed by the MBRA.

Table 8-8: Initial failure frequency for centrifugal pumps


Centrifugal pump with seals

S1.a Rupture of the pump suction line and ESD action 1.0*10-4

per year

S1.b Rupture of the pump suction line arm without ESD action 1.0*10-7

per year


per year

Table 8-9 and Table 8-10 will give detailed information about the scenarios that are modeled


mentioned in Table 8-7. The factor 1.5 is used to take into account the increasing pump flow due

to the pipeline ruptures.

Table 8-9: Details of failure scenarios of the sent out pump

Number

of

pumps

Scenario Orifice

diameter

[inch]

Exit velocity

[m/s]

Mass

rate

[kg/s]

Time[s] Failure

frequency

per pump

[1/yr]

Time

fraction

in use [-]

Total

failure

frequency

[1/yr]

2 S1.a 24 0.3 72.9 120 1.0 x 10-4

1 2.0 x 10-4

2 S1.b 24 0.3 72.9 1800 1.0 x 10-7

1 2.0 x 10-7

2 S2 2.4 1800 4.4 x 10-3

1 8.8 x 10-3

DET NORSKE VERITAS


MANAGING RISK




Table 8-10: Details of failure scenarios loading pump (during loading activities)

Number

of

pumps

Scenario Orifice

diameter

[inch]

Exit

velocity

[m/s]

Mass

rate

[kg/s]

Time[s] Failure

frequency

per pump

[1/yr]

Time

fraction

in use [-]

Total

failure

frequency

[1/yr]

1 S1.a 20 7.7 1198 120 1.0 x 10-4

0.13 1.3 x 10-5

1 S1.b 20 7.7 1198 1800 1.0 x 10-7

0.13 1.3 x 10-8

1 S2 2 117 51.1 1800 4.4 x 10-3

0.13 5.8 x 10-4

Table 8-11: Details of failure scenarios loading pump (no loading activities)

Number

of

pumps

Scenario Orifice

diameter

[inch]

Exit

velocity

[m/s]

Mass

rate

[kg/s]

Time[s] Failure

frequency

per pump

[1/yr]

Time

fraction

in use [-]

Total

failure

frequency

[1/yr]

1 S1.a 20 116 2348 18 1.0 x 10-4

0.87 8.7 x 10-5

1 S2 2 116 46.8 1800 4.4 x 10-3

0.87 3.8 x 10-3

8.2.4 Piping

Pressurized CO2 will be received at the terminal via the incoming pipelines from emitter B and

the low pressure pipeline network located in the Port of Rotterdam. The 16 inch pipeline from

emitter B and 20 inch hub pipeline will deliver a continuously mass flow of 136 kg/s to the

terminal. The incoming CO2 will be liquefied in the liquefier. After the liquefaction process 64%

of the CO2 will be sent to the storage tanks and 36% will be sent to the send out pump. From the

storage tanks CO2 will be transferred with a 20 inch pipeline to the loading facility. An overview

of the pipelines is given in Figure 8-3. More detailed information about the characteristics of the

different pipelines that are modeled is found in Table 8-12.

Figure 8-3: Layout drawing of the modeled piping

DET NORSKE VERITAS


MANAGING RISK




Table 8-12: Characteristic of the piping (first two are above ground, rest under gorund)

Piping trajectory Pressure suction

line [bar]

Temperature

[°C]

Diameter

[inch]

Mass flow

rate [kg/s]

Time

fraction in

use [-]

Incoming CO2 network line 30 30 20 39 1

Incoming CO2 emitter B line 30 30 16 80 1

Pump to loading facility line 7 -50 20 799 0.13

Liquefier to storage tanks line 7 -50 6 86 1

Send-out pipe 84 28 24 49 1

During the transfer of CO2 by piping different loss of containment scenarios can occur. The loss

of containment scenarios that occurs depends on the location of the piping. Loss of containment

of CO2 from lines that are located beneath the surface will have different effects than lines that

are located above the surface. Table 8-13 summarizes the loss of containment scenarios for

piping above and underneath the ground as prescribed by the MBRA.

Table 8-13: Initial failure frequency for piping


Underground piping

S1.a Rupture of an pipeline and ESD action 7.0*10-9

per meter per year

S1.b Rupture of an pipeline without ESD action 7*10-12

per meter per year


per meter per year

Piping 75<D<150 mm >150 mm

S3.a Rupture of a pipeline and ESD action 3.0*10-7

1/m yr 1.0*10-7

1/m yr

S3.b Rupture of a pipeline without ESD action 3.0*10-7

1/m yr 1.0*10-7

1/m yr


1/m yr 5.0*10-7

1/m yr

Table 8-14 till Table 8-18 will give detailed information about the scenarios that are modeled


mentioned in Table 8-7 to take into account the increasing pump flow.

Table 8-14: Details of failure scenarios of the incoming CO2 network line

Scenario Orifice

diameter

[inch]

Exit

velocity

[m/s]

Mass

rate

[kg/s]

Time[s] Failure

frequency

[1/ m yr]]

Time

fraction in

use [-]

Number

of

meters

piping

Total

failure

frequency

[1/yr]

S1.a 20 0.4 59 120 7.0 x 10-9

1 100 7.0 x 10-7

S1.b 20 0.4 59 1800 7.0 x 10-12

1 100 7.0 x 10-10

S2 2 401 2.6 1800 6.3 x 10-8

1 100 6.3 x 10-6

DET NORSKE VERITAS


MANAGING RISK




Table 8-15: Details of failure scenarios of the incoming CO2 emitter B line

Scenario Orifice

diameter

[inch]

Exit

velocity

[m/s]

Mass

rate

[kg/s]

Time[s] Failure

frequency

[1/ m yr]

Time

fraction in

use [-]

Number of

meters

piping

Total failure

frequency

[1/yr]

S1.a 16 1.2 120 120 7.0 x 10-9

1 24 1.7 x 10-7

S1.b 16 1.2 120 1800 7.0 x 10-12

1 24 1.7 x 10-10

S2 1.6 1800 6.3 x 10-8

1 24 1.5 x 10-6

Table 8-16: Details of failure scenarios of pump to loading facility line (during loading)

Scenario Orifice

diameter

[inch]

Exit

velocity

[m/s]

Mass

rate

[kg/s]

Time[s] Failure

frequency

[1/ m yr]

Time

fraction in

use [-]

Number of

meters

piping

Total failure

frequency

[1/yr]

S1.a 20 4.9 1198 120 1.0 x 10-7

0.13 181 2.4 x 10-6

S1.b 20 4.9 1198 1800 1.0 x 10-10

0.13 181 2.4 x 10-9

S2 2 1800 5.0 x 10-7

0.13 181 1.2 x 10-5

Scenario Orifice

diameter

[inch]

Exit

velocity

[m/s]

Mass

rate

[kg/s]

Time[s] Failure

frequency

[1/ m yr]

Time

fraction in

use [-]

Number of

meters

piping

Total failure

frequency

[1/yr]

S1.a 20 116 2348 18 1.0 x 10-7

0.87 181 1.6 x 10-5

S2 2 116 46.8 1800 5.0 x 10-7

0.87 181 7.9 x 10-5

Table 8-17: Details of failure scenarios of liquefier to storage tanks line

Scenario Orifice

diameter

[inch]

Exit

velocity

[m/s]

Mass

rate

[kg/s]

Time[s] Failure

frequency

[1/ m yr]

Time

fraction in

use [-]

Number of

meters

piping

Total failure

frequency

[1/yr]

S1.a 6 9.2 130 120 1.0 x 10-7

1 338 3.4 x 10-5

S1.b 6 9.2 130 1800 1.0 x 10-10

1 338 3.4 x 10-8

S2 0.6 117 4.6 1800 5.0 x 10-7

1 338 1.7 x 10-4

Table 8-18: Details of failure scenarios of the sent out line

Scenario Orifice

diameter

[inch]

Exit

velocity

[m/s]

Mass

rate

[kg/s]

Time[s] Failure

frequency

[1/ m yr]

Time

fraction in

use [-]

Number of

meters

piping

Total failure

frequency

[1/yr]

S1.a 6 5.2 73 120 1.0 x 10-7

1 100 3.4 x 10-5

S1.b 6 5.2 73 1800 1.0 x 10-10

1 100 3.4 x 10-8

S2 0.6 1800 5.0 x 10-7

1 100 1.7 x 10-4

DET NORSKE VERITAS


MANAGING RISK




8.2.5 Liquefaction unit

CO2 gas from the low pressure pipeline network and emitter B is liquefied in the liquefaction

unit. The liquefaction unit consists of a compressor, heat exchanger and a cold box. This section

will give more detailed information about the configuration and loss of containment scenarios

that can occur with the equipment in the liquefaction unit.

8.2.5.1 Compressor

First the CO2 will be compressed from 7 to 80 barg with a two stages compressor. Each of the

compressors stages is modeled as a separate compressor. The failure cases that are modeled for

the compressor are listed in Table 8-19.

Table 8-19: Initial failure frequency for compressors


Centrifugal compressor

S1.a Rupture of compressor and ESD action 5.0*10-5

per year

S1.b Rupture of compressor without ESD action 5.0*10-8

per year

S2 leakage of compressor, hole with 10% of the diameter of the

connection line

1.0*10-3

per year


Table 8-20: Details of failure scenarios of the compressors

Number

of

pumps

Scenario Orifice

diameter

[inch]

Exit

velocity

[m/s]

Mass

rate

[kg/s]

Time[s] Failure

frequency per

pump [1/yr]

Time

fraction

in use [-]

Total failure

frequency

[1/yr]

2 S1.a 24 0.3 72.9 120 5.0 x 10-5

1 5.0 x 10-5

2 S1.b 24 0.3 72.9 1800 5.0 x 10-8

1 5.0 x 10-8

2 S2 2.4 349 48.6 1800 1.0 x 10-3

1 1.0 x 10-3

8.2.5.2 Heat exchanger

Due to the compression of the CO2 the temperature will increase. A decrease of the

temperature will be accomplished by cooling the CO2 with surface water. The failure cases

that are modeled for the heat exchanger are listed in Table 8-21 and the detailed

information in

Table 8-22.

Table 8-21: Initial failure frequency for a heat exchanger


Shell side condenser


per year


per year

DET NORSKE VERITAS


MANAGING RISK





per year


per year


Scenario Orifice

diameter [inch]

Volume

released [m3]

Exit velocity

[m/s]

Mass rate

[kg/s]


frequency [1/yr]

S1.a 24 1 0.3 72.9 120 5.0 x 10-5

S1.b 24 1 0.3 72.9 1800 5.0 x 10-8

S2 n/a 1 349 0.03 1800 5.0 x 10-5

S3 0.4 1 349 5 1800 1.0 x 10-3

8.2.5.3 Cold box

The liquefaction process takes places at low temperatures. Thermal insulation is used to minimize

temperature losses due to heat transfer from equipment to the surrounding. The cold box provides

the thermal isolation of the equipment. The main equipments that are present in the cold box are

heat exchangers, separation pressure vessels and associated piping.

The height of the cold box is 10 meter. On the top it is equipped with a 24 inch vent to prevent

overpressures in case a loss of containment from equipment in the cold box occurs. The total

volume of gas and liquid of the equipment in the cold box is 90 and 35 m3 respectively. More

detailed information of the cold box is not available from the vendor. It is assumed that there is

100 meters of piping in the cold box. Half of the piping will contain vapor and the other half will

contain liquid. It is also assumed that most of the volume is present in the heat exchangers and

the volume in the separation vessels is negligible. The cold box will contain small plate fin heat

exchangers which are modeled as a large heat exchanger. The process conditions of the cold box

are summed in Table 8-23.

Table 8-23: Characteristic of the cold box

Equipment in cold box Phase Pressure [bar] Temperature [°C] Volume [m3]

Heat exchanger Liquid 80 25 20.4

Heat exchanger Vapor 80 25 75.4

Piping Liquid 80 25 14.6

Piping Vapor 80 25 14.6

Heat exchanger

Vapor CO2 will flow with a mass flow of 136 kg/s through a plate fin heat exchanger where

it will be liquefied. The liquefied CO2 will leave the heat exchanger with the same mass

flow. In the heat exchanger different loss of containment scenarios can occur.

Table 8-24 summarizes the loss of containment scenarios that can occur with a heat exchanger as

prescribed by the MBRA and Table 8-25 gives the detailed information about these scenarios.

DET NORSKE VERITAS


MANAGING RISK




Table 8-24: Initial failure frequency for plate-fin heat exchangers


Shell side heat exchanger


per year


per year


per year


per year


Scenario Orifice

diameter

[inch]

Volume

released

[m3]

Release

height

[m]

Exit

velocity

[m/s]

Mass rate

[kg/s]


frequency

[1/yr]

Vapour

S1.a 24 17100 10 0.9 204 120 5.0 x 10-5

S1.b 24 246000 10 0.9 204 1800 5.0 x 10-8

S2 n/a 754 10 0.4 1.3 600 5.0 x 10-5

S3 0.4 308 10 356 0.2 1800 1.0 x 10-3

Liquid

S1.a 24 40800 10 0.9 204 120 5.0 x 10-5

S1.b 24 269000 10 0.9 204 1800 5.0 x 10-8

S2 n/a 754 10 0.4 1.3 600 5.0 x 10-5

S3 0.4 3564 10 117 2 1800 1.0 x 10-3


The weather, population and other background data that are used to calculate the consequences

and risk results are explained in more detail in the following paragraph.

Weather data


the Hoek van Holland weather station.

Surface roughness





DET NORSKE VERITAS


MANAGING RISK




Population data

In the north, east and west of the terminal different industrial activities take place. The chemical

company Lyondell-Bayer is located on the east side of the terminal. The power company E-on is

located in the south-east of the terminal. The number of employees that is present day and night

from both companies is obtained from the population file provided by The Dienst Centraal

Milieubeheer Rijnmond (DCMR). The area in the south of the terminal is reserved for a chemical

company. Because of the lack of information regarding the number of people that are present on

this area the generic number of 5 people per hectare, prescribed by the MBRA, is used. The north

of the terminal is reserved for container terminal activities. The number of employees that is

presented on this area is estimated with the same generic number as described above.

Figure 8-4 Surrounding of the terminal

DET NORSKE VERITAS


MANAGING RISK





The next paragraphs will show the consequences for some loss of containment scenarios for the

storage tanks and cold box. For the different LOC scenarios the maximum concentration profile

has been calculated as well as the lethality footprint.












happen).

8.3.1 Storage tank

After a storage tank is ruptured a CO2 cloud will be formed. The direction and speed at which the

cloud drifts away depends on the wind direction and wind speed. Figure 8-5 shows, for a F1.5

weather type, the drifted CO2 cloud when it reaches the maximum distance for dangerous CO2

concentrations. The dangerous concentrations (50,000 ppm) can reach up to 680 meters of the

release location.

After 116 seconds the CO2 cloud is diluted such that no dangerous concentration is present. The

distance where the alarm value concentration reaches its maximum value equals 1260 meters.

This effect distance is reached 2 minutes after the initial rupture. Figure 8-6 shows the drifted

CO2 cloud after 2 minutes.

The lethal footprint in Figure 8-7 shows that the maximum distance from the release location at

which fatalities can occur is at 680 meters.

DET NORSKE VERITAS


MANAGING RISK






DET NORSKE VERITAS


MANAGING RISK




Figure 8-7: Lethality footprint for a tank rupture

Figure 8-8 shows the maximum concentration of CO2 for a 10 mm leakage of the storage tank.

The dangerous concentrations (50,000 ppm) reaches not further than 9.5 meters of the release

location.

Figure 8-8: Side view of maximum concentration of 10 mm leakage of storage tank

DET NORSKE VERITAS


MANAGING RISK




8.3.2 Cold box

CO2 will be released in the hull of the cold box when there is a leak or rupture of equipment in

the cold box. The release CO2 can only leave the cold box by a 24 inch vent that is placed on top

of box. A vapor release due to a LOC in the cold box will increase the pressure in the cold box. If

the pressure increases further than the set point of the vent, pressurized vapor will be discharged

through the vent to the atmosphere. Figure 8-9 shows the side view of the discharged

concentration via the vent in case of a vapor line rupture. It is seen that dangerous concentrations

will not occur at ground level.

Figure 8-9: Release of vapor by the vent of the cold box

During a LOC of liquid pressurized CO2 the discharge temperature will decrease to -87.5° C, due

to the expansion of CO2 to atmospheric pressure. At atmospheric pressure and -87.5° C the phase

of CO2 is solid and dry ice will be formed. The ice particle will have a downwards movement due

to the higher density then the air in the cold box. The thermodynamic theory determines that CO2

cannot exist in the liquid phase at atmospheric pressure. At atmospheric pressure CO2 will be

either in the vapor phase or exist as two phase mixture of solid phase CO2. The formed dry ice

sublimates at atmospheric pressure directly into vapor. The vapor will be discharged through the

vent to the atmosphere. The vapor release will show the same behavior as seen in Figure 8-9.

DET NORSKE VERITAS


MANAGING RISK





Figure 8-10 and Figure 8-11 display the individual risk contours for the CO2 terminal. Figure

8-10 depicts a close-up of the risk contours at the terminal and Figure 8-11 depicts the same risk

contours at the same location in a larger overview of the Port. The maximum calculated

individual risk outside the terminal boundary is in the order of 10-5

/year or less and is thereby

higher than the maximum acceptable individual risk criteria of 10-6

/year. The individual risk

contour of 10-5

and 10-6

/year crosses the plant boundary at an area that is reserved for chemical

activities. Because this area is not reserved for vulnerable objects these results do not conflict

with regulatory requirements.

The outdoor individual risk at which people are exposed at the office location is given in Table

8-26. Most of the risk is caused by the rupture of the compressor.

Table 8-26: Risk contributors at the office location


Rupture of compressor 5.9 x 10-6

57.8


18.9


8.6

The outdoor individual risk at which people are exposed at public road in the North East of the

terminal is given in Table 8-27. More then half of the risk is caused by combination of the rupture

of the loading arm, compressor and loading pump.

Table 8-27: Risk contributors at the public road



22.2

Rupture of compressor 1.9 x 10-7

20.4

Rupture loading pump 1.5 x 10-7

16.1


8.5


8.1


7.9


7.7

DET NORSKE VERITAS


MANAGING RISK




Figure 8-10: Individual risk CO2 terminal at the Port of Rotterdam

Figure 8-11: An overview plot of the individual risk CO2 terminal at the port of Rotterdam

DET NORSKE VERITAS


MANAGING RISK




Figure 8-12: Societal risk CO2 terminal at the port of Rotterdam

Figure 8-12 shows the calculated societal risk (blue line) for the CO2 terminal. The red line

represents the maximum group risk criteria: the calculated societal risk is below the target

criteria.


In this chapter the individual and societal risk has been calculated for the CO2 terminal in the Port

of Rotterdam. The individual risk calculations for the terminal generated a maximum individual

risk outside the terminal in the order of 10-5

/year or less. The area that is exposed to these

contours does not contain vulnerable objects therefore these results do not break with regulatory

requirements. The societal risk is below the target criteria.

DET NORSKE VERITAS


MANAGING RISK




9 TRANSPORT OF CO2 BY SEA GOING VESSELS

9.1 Introduction

Part of the incoming CO2 at the terminal will be shipped via seagoing vessels to an offshore

location. The seagoing vessels will transport the CO2 at a temperature of -50°C and a pressure of

7 bara. The CO2 will be transported in liquid phase because liquid CO2 has got a higher density

than gaseous CO2, which means that more CO2 can be transported at one time. The seagoing

vessels have a transport capacity of 30,000 m3 each, which is distributed in several separate tanks.

Depending on the chosen ship design, standard or X-Bow, the tanks can vary between 3,000 m3

up to 6,000 m3. It is assumed that yearly 96 seagoing vessels visit the terminal to load CO2 and

transport it to an offshore location.

The safety study will consider the CO2 transport from the CO2 terminal located in the Port of

Rotterdam to the exit of the Port (Maasmond), since the study focuses on the risk to the onshore

external population and not so much on the risks to other marine activities.

Figure 9-1 depicts the shipping route from the CO2 terminal located in the Port of Rotterdam.

Figure 9-1: Shipping route seagoing vessels in the Port of Rotterdam

The CO2 transported on the water could pose an external risk due to collision scenarios or an

accidental release from the above-deck piping of the seagoing vessel. In this chapter the

consequences and risks of the seagoing shipping activities will be calculated and evaluated.

DET NORSKE VERITAS


MANAGING RISK




9.2 Scenarios

Accident scenarios of seagoing vessels in transit consist out of LOC scenarios due to internal

failure (e.g. leak of piping) or due external failure (e.g. collision).

The first group includes aspects like mechanical failure, material/construction errors,

fire/explosions, failure of cooling system etc. which are not waterway related. Collision accidents

on the other hand are related to a waterway.

The safety study will assess two possible LOC scenarios for the seagoing vessel:

1. A small leak

A leak in the cargo tank (5,000 m3) with a diameter of 250 mm (10 inch) corresponding with a

typical diameter of (un)loading connection.

2. A large leak

A leak in the cargo tank (5,000 m3) with a diameter of 1100 mm (1.0 m

2).

These LOC scenarios were taken from the Protocol Risicoanalyse zee- en binnenvaart [Ref 21].

9.2.1 Modeling LOC scenarios seagoing vessels

The leak scenarios have been modeled with a leak model in Safeti-NL. The LOC scenarios have

been modeled with a release height of 1 meter and a horizontal release direction.




9.2.1.1 Modeling of LOC scenarios of liquid CO2

The leak scenarios have been modeled with a pressure of 7 bara and a temperature of -50 ºC.

Under these conditions the CO2 is in liquid phase and solid (ice) formation will take place when a

LOC scenario occurs (see also paragraph 2.1.4.2).

The LOC scenario of a tank will firstly drain liquid CO2 until the liquid CO2 level is lowered to

the release height of the tank. At that moment, the tank will depressurize, the remaining liquid

CO2 in the tank starts evaporating and only vapor CO2 will be released through the leak. The

liquid CO2 in the tank will cool down due to the evaporation of the CO2. When the liquid CO2

cools down to −78 °C all the remaining CO2 will instantly turn into solid CO2. It is assumed in

the calculations that 2/3 of the inventory of the tank will be released before the remaining CO2

turns into solid CO2. This is based on the assumption that the leak of the tank is located at half the

tank height and part of the CO2 has to be evaporated to cool down the remaining liquid CO2.

Part of the released liquid CO2 will “rain” out from the CO2 jet as solid CO2 and sublimates from

the water. This sublimation will cause locally, at the release location, a higher CO2 concentration.

However, the influence of the sublimating CO2 is negligible compared to the release of gaseous

CO2. Therefore, this effect is not considered for horizontal releases and it is assumed that all the

DET NORSKE VERITAS


MANAGING RISK




CO2 will be released as vapor. This is a conservative assumption and the calculated effect is as a

result larger than in reality.


The next paragraphs will show and explain the effects of a LOC of seagoing vessels. For each

LOC scenario the maximum concentration profile has been calculated as well as the lethality

footprint.












happen).

9.3.1 LOC scenarios of a seagoing vessel

The figures below show the consequences of a small and large leak of a CO2 seagoing vessel due

to a collision at the exit of the second Maasvlakte near the town of Hoek van Holland located

opposite of the Nieuwe waterweg (see Figure 9-1).

Figure 9-2 shows the maximum concentration footprint of a small leak (250 mm) at one of the

tanks of the seagoing vessel. The CO2 jet is directed horizontally and dangerous CO2

concentrations (50,000 ppm, brown line) can reach up to 345 meters of the release location (440

meters for D5).

The lethality footprint in Figure 9-3 confirms the distance found in Figure 9-2. The maximum

distance from the release location at which fatalities can occur is indicated by the blue contour

and is at around 320 meters (390 meters for D5) from the CO2 seagoing vessel.

DET NORSKE VERITAS


MANAGING RISK




Figure 9-2: Concentration profile of a small leak (250 mm)

Figure 9-3: Maximum lethality footprint of a small leak (250 mm)

DET NORSKE VERITAS


MANAGING RISK




Figure 9-4 shows the maximum concentration footprint of a large leak (1100 mm) at one of the

tanks of the seagoing vessel. The CO2 jet is directed horizontally and dangerous CO2

concentrations (50,000 ppm, brown line) can reach up to 790 meters of the release location (950

meters for D5).

Figure 9-4: Concentration profile of a large leak (1100 mm)

Figure 9-5: Maximum lethality footprint of a large leak (1100 mm)

DET NORSKE VERITAS


MANAGING RISK




The lethality footprint in Figure 9-5 confirms the distance found in Figure 9-4. The maximum

distance from the release location at which fatalities can occur is indicated by the blue contour

and is at around 630 meters (710 meters for D5) from the CO2 seagoing vessel.


In this section the consequences, concentration and lethality, have been calculated for the LOC

scenarios of the seagoing vessels.

Dangerous CO2 concentrations (50,000 ppm) due to a small leak (250 mm) at one of the tanks

of a seagoing vessel can reach up to 440 meters.

The 1% lethality range of a small leak (250 mm) at one of the tanks of a seagoing vessel is

390 meters.

Dangerous CO2 concentrations (50,000 ppm) due to a large leak (1100 mm) at one of the

tanks of a seagoing vessel can reach up to 950 meters.

The 1% lethality range of a large leak (1100 mm) at one of the tanks of a seagoing vessel is

710 meters.

The leak scenarios have been modeled at the middle of the shipping lanes. The seagoing vessels

carrying CO2 could be located at any place of the shipping lane when a leak occurs. This means

that dangerous CO2 concentrations can reach the shore due to a leak of a seagoing vessel and

fatalities can occur.

However, the results of the consequence calculations show that dangerous CO2 concentrations

will not reach the town of Hoek van Holland. Between the Calandkanaal and the Nieuwe

Waterweg a splitting dam is located to separate the shipping towards the second Maasvlakte / the

Europoort and the rest of the port, which prevents possible drifting of the CO2 seagoing vessels

towards the town of Hoek van Holland. Therefore, areas that are possibly affected when a leak at

one of the cargo tanks of the seagoing vessel occurs are limited to the industrial Maasvlakte area.

Vulnerable objects are not located in this area and therefore a risk assessment is not needed

according to the Dutch risk criteria.

DET NORSKE VERITAS


MANAGING RISK




10 TRANSPORT OF CO2 BY PIPELINE (HIGH PRESSURE)

10.1 Introduction

It is foreseen to transport the CO2 from the terminal to the storage locations via a high pressure

(HP) pipeline. At the moment the ROAD project1 is planning to transport CO2 via a HP pipeline

to an empty gas field in the North Sea. ROAD is an abbreviation for Rotterdam Afvang en

Opslag Demonstratieproject which translates into Rotterdam Capture and Storage Demonstration

project. The ROAD project is a demonstration project to demonstrate CCS on an industrial scale.

From 2015 onwards the project will store 1.1 Mtons of CO2 per year.

The ROAD project is located near the possible location of the CO2 terminal. It is highly likely

that the CO2 terminal will tie-in on the ROAD pipeline. Therefore, the QRA will consider the

pipeline route used by the ROAD project. Figure 10-1 depicts the onshore routing of the HP

pipeline network.

The HP pipeline will be mostly located underground, only at the site location the pipeline is

located aboveground, and crosses the Yangtze harbor and the Maasgeul. The risk calculations of

the pipeline QRA will only consider the onshore underground section, the section of pipeline

located aboveground is not considered in the safety study.

Figure 10-1: Onshore route high pressure pipeline

1 The initiator of the ROAD project is the joint venture Maasvlakte CCS Projects CV, consisting out of E.ON Benelux and

Electrabel (Group GDF SUEZ). The joint venture will cooperate with GDF SUEZ E&P Netherlands BV en TAQA Energy for

respectively the transport and injection / storage.

DET NORSKE VERITAS


MANAGING RISK




The total length of the onshore pipeline is about 5.2 kilometers, the diameter is 16 inch (~40 cm)

and the minimum pipeline cover is 100 cm. Initially the CO2 will be transported in gas phase and

in a later stage in dense phase. The QRA will consider that the CO2 is transported in dense phase

since this is the worst case due to higher flows. The operating condition of the pipeline is 130

bara and the maximum operating temperature is 80 ºC. The design flow is 47 kg/s. Before

entering the Maasgeul the pipeline shall be equipped with a block valve station.

10.2 LOC scenarios and frequencies

Transport pipelines can fail due to internal causes (e.g. corrosion, pressure above design pressure)

and due to external interference (e.g. groundwork). The safety study will assess two possible

LOC scenarios: a rupture of the pipeline and a leak of the pipeline. In Table 10-1 and Table 10-2

the LOC scenarios and their corresponding frequencies are listed. These were taken from the

Reference Manual Bevi Risk Assessments (MBRA).

Table 10-1: LOC scenarios for underground transport pipelines

Frequency


Pipeline in pipe bay

Frequency


Pipeline complies with

NEN 3650

Frequency


Other pipelines


1.525 × 10-7

5 × 10-7

2. Leak with a diameter of

20 mm 6.3 × 10

-8 4.575 × 10

-7 1.5 × 10

-6

Table 10-2: LOC scenarios for aboveground pipelines

Frequency


nominal diameter < 75

mm

Frequency


75 mm ≥ nominal

diameter ≤ 150 mm

Frequency


nominal diameter > 150

mm


3 × 10-7

1 × 10-7

2. Leak with an effective

diameter of 10% of the

nominal diameter, up to a

maximum of 50 mm

5 × 10-6

2 × 10

-6

5 × 10-7

The failure frequencies for underground pipelines are lower than aboveground pipelines because

underground pipelines are more protected against external impact. Underground pipelines can

have different additional safety measures, both technical and organizational, which will influence

the failure frequencies. For this reason three different failure frequencies can be used for

underground pipelines.

The high pressure pipeline is not located in a pipe bay, but the pipeline complies with NEN 3650

and therefore these failure frequencies are used for the risk calculations for the underground

sections. For the pipeline sections crossing the waterways the failure frequency for a pipeline in a

pipe bay is used as it is highly unlikely that this segment is damaged by impact.

DET NORSKE VERITAS


MANAGING RISK




10.3 Modeling pipeline LOC scenarios

The pipeline rupture scenarios have been modeled with the “long pipeline” model in Safeti-NL

which means that the 2-sided outflow during a pipeline rupture is considered in the calculations.

During normal operation the pressure in the pipeline decreases due too internal friction. As a

result the discharge upon a rupture will vary depending on where the pipeline ruptures. To take

this into account, the pipeline rupture scenario is modeled with 5 consecutive pipeline segments,

each having their own (decreasing) pressure setting resulting in a different discharge.

The underground pipeline scenarios have been modeled with a release height of 0 meter and a

vertical release direction. It is expected that a crater will be formed during the release and that

there is no loss of momentum of the CO2 jet. The aboveground scenarios have been modeled with

a release height of 1 meter and a horizontal release direction. These assumptions are all according

to MBRA.

The pipeline crossings under the Yangtze harbor and the Maasgeul will be done via HDD and are

located at a depth of more than 30 meters. A LOC of a pipeline at such depth will lose

momentum and which should be taken into account. The Dutch guidelines are not specific on

how to model LOC scenarios of pipelines located under waterways.

In case of a gas release underwater a bubble plume will form (see Figure 10-2). This bubble

plume will decrease the release velocity and prevent jet dispersion. This risk analyses assumes a

surface diameter of the bubble plume of 30% of the pipeline depth, based on the guideline for risk

analysis from the international Association of Oil and Gas Producers (OGP) [Ref 22] and the

research done by the Petroleumtilsynet for Norpipe [Ref 23].

The OGP guideline calculates a surface diameter of the bubble plume of 20% of the pipeline

depth. However, because for a CO2 release a low release velocity will result in larger effects the

conservative diameter of 30% was used, based on the analyses done by the Petroleumtilsynet.

The CO2 velocity at the surface was determined with the release rate and surface area of the

plume. The CO2 temperature, to calculate the density, was assumed equal as the water

temperature due to the intense mixing with the water during the release.

The dissolving of CO2 in the water is not considered in the calculations, which is a conservative

assumption.




DET NORSKE VERITAS


MANAGING RISK




Figure 10-2: Steady-state bubble plumes with surface flow [Ref 23]

The situation after a rupture pipeline leak will give a near zone (bubble zone) above the leak

point and a CO2 cloud outside the near zone. There have been raised some concerns about the

potential loss of buoyancy if vessels sail into, or are in the bubble zone at the time of release.

In earlier risk assessments performed for offshore hydrocarbon pipelines, the potential hazard of

sinking ship/vessels due to loss of buoyancy has been considered negligible. This is partly based

on conclusions from a study performed in 1987, Marintek called “Risk Assessment of Buoyancy

Loss – RABL/PP2”. The report focuses mainly on the effect on semi-submersible platforms

subjects to a subsea gas blowout, but addresses some effects on vessels sailing away from the gas

release as well. The main conclusion from this study is that the effects of buoyancy loss do not

represent any risk to vessels sailing away from the near zone. The conclusion of the tests was that

the effect of the upward velocity more than counteracts the one of buoyancy loss. The tests

indicate no risk for capsizing as long as the compartments are closed. However the motions are

severe.

However, the evaluation of this potential hazard was based on the assumption that a scenario with

CO2 in principle will be the same as a heavy hydrocarbon gas release.

DET NORSKE VERITAS


MANAGING RISK




10.3.1 Modeling of a LOC scenario of dense phase CO2

The rupture and leak scenarios have been modeled with the maximum outlet pressure of 130 bara

and a maximum operating temperature of 80 ºC. Under these conditions the CO2 is in dense

phase and solid (ice) formation could take place when a LOC occurs (see also paragraph 2.1.4.2).

Dry ice sublimates at atmospheric pressure directly into vapor. Safeti-NL does not accurately take

this effect into account. Therefore, an extra model in the consequence and risk calculations for

the vertical releases is used to make sure that solid formation is considered.

Horizontal release

During a horizontal release the dry ice will “rain” out from the CO2 jet and then slowly

sublimates from the ground. This sublimation will cause a higher CO2 concentration at the release

location. However, the influence of the sublimating CO2 is negligible compared to the direct

effect of the gaseous CO2 release. Therefore, the sublimation effect is not considered for

horizontal releases and it is assumed that all the CO2 will be released as vapor. This is a

conservative assumption as the calculated effect will be larger than in reality.

Vertical release

A vertical CO2 release will most of the times not cause dangerous CO2 concentrations at ground

level. However, when solid formation occurs, the sublimation of dry ice may cause a dangerous

CO2 concentration at the release location. Therefore, solid formation will be considered for

vertical releases to prevent underestimation of the consequences and risks.

The amount of dry ice formed during a release is determined with the Mollierdiagram of CO2. A

fully isentropic process is assumed for the CO2 release is. The dry ice is modeled in Safeti-NL as

a “user defined source” at which the CO2 vapor is released vertically with a low velocity and a

low temperature. The flow is set equal to the solid formation, which is a conservative assumption.


Appendix 2 shows and explains the effects of LOC scenarios from the HP pipeline, both

aboveground, underground and at a waterway crossing. For each LOC scenario the maximum

concentration profile has been calculated as well as the lethality footprint.












happen).

DET NORSKE VERITAS


MANAGING RISK




Table 10-3 summarizes the results of Appendix 2. It shows the effect distances for the different

HP scenarios.

Table 10-3: Effect distances HP pipeline scenarios

Location Scenario Distance 50,000 ppm (m) Distance 1% lethality (m)

F1.5 D5 F1.5 D5

Aboveground Rupture 300 285 156 145

Leak 44 40 37 35

Underground Rupture 10 10 8 8

Leak <0.5 <0.5 <0.5 <0.5

Waterway crossing Rupture 1980 355 740 210

Leak 50 28 <1 <1


In this section the consequences, concentration and lethality, have been calculated for the LOC

scenarios for a HP pipeline.

Dangerous CO2 concentrations (50,000 ppm) at ground level due to a LOC of an

aboveground pipeline can reach up to 300 meters and the 1% lethality contour reaches 156

meters.

Dangerous CO2 concentrations (50,000 ppm) at ground level due to a LOC of an underground

pipeline do not reach far because the CO2 jet is directed vertically and the CO2 concentration

is quickly diluted before reaching the ground again. At the release location some solid

formation occurs which causes dangerous CO2 concentrations at the release location.

Although the release of a LOC of a pipeline crossing a waterway is directed vertically, as for

the underground pipeline, dangerous CO2 concentrations (50,000 ppm) at ground level can

reach up to 1980 meters and 1% lethality contour reaches 740 meters. This is caused by the

loss of momentum of the jet which lowers the air entrainment and thereby lowers the dilution

of CO2.

DET NORSKE VERITAS


MANAGING RISK




10.5 Risk assessment

The risk calculations combine the consequences with the frequency of an LOC scenario. The next

paragraphs show the risk results of the HP pipeline. The aboveground pipeline risk calculations

should be integrated in the terminal QRA because the pipeline will go underground at the CO2

terminal site and is therefore not considered in this safety study.


The risk calculations use weather and population data to calculate the individual and societal risk.

Weather data


the Hoek van Holland weather station. These data are considered to be representative for the

complete route.

Surface roughness





Population data

The Dienst Centraal Milieubeheer Rijnmond (DCMR) provided the population file for the

Rotterdam region which was used for the societal risk calculations. In the calculations for the

societal risk is assumed that the population inside a building is more protected. In accordance

with MBRA a factor of 0.1 was used to take this into account.

10.5.2 Risk results HP pipeline

Figure 10-3 displays the individual risk contours for the HP pipeline. The individual risk for the

high pressure pipeline generated a maximum individual risk of 10-6

/year at the offshore section

and less than 10-6

/year at the onshore section. The risk at the offshore section is higher than the

maximum acceptable individual risk criteria of 10-6

/year, but this risk criterion is only applicable

for onshore pipelines. A 10-6

/year individual risk contour at the onshore section would mean that

no vulnerable objects should be located in this contour. Because the pipeline is located in an

industrial area no vulnerable objects are located near the pipeline. The large 10-7

/year and 10-

8/year risk contours are generated by the pipeline rupture under the waterways.

DET NORSKE VERITAS


MANAGING RISK




Figure 10-3: Individual risk HP pipeline

Figure 10-4: Societal risk HP pipeline

DET NORSKE VERITAS


MANAGING RISK




Figure 10-4 shows the calculated societal risk (blue line) for the HP pipeline. The red line

represents the maximum group risk criteria: the calculated societal risk is below the target

criteria. The FN curve stops at a low of fatalities because the pipeline is located in an industrial

area.


In this section the individual and societal risk has been calculated for the high pressure pipeline.

The individual risk calculations for the high pressure pipeline generated a maximum individual

risk of 10-6

/year at the offshore section and less than 10-6

/year at the onshore section. The risk at

the offshore section is higher than the maximum acceptable individual risk criterion of 10-6

/year,

but this risk criterion is only applicable for onshore pipelines. The societal risk is below the target

criteria.

10.6 Conclusion

In this chapter a safety assessment was made for the high pressure pipeline coming from ROAD

and going offshore. The consequence assessment calculated the effects of two LOC scenarios,

rupture and leak, for the pipeline. The calculations were done for the different possible locations

of the pipeline: aboveground, underground and crossing the waterway. A LOC scenario of the

different locations can all lead to fatalities.

Therefore, a risk assessment was needed to calculate the risk of the pipeline and assess whether

the risk is acceptable or whether mitigation is needed. The section of the pipeline located

aboveground is only located at the site of the different emitters and at the CO2 terminal.

Therefore, the risk of this part of the pipeline should be considered in the terminal QRA.

The individual risk calculations for the high pressure pipeline generated a maximum individual

risk of 10-6

/year at the offshore section and less than 10-6

/year at the onshore section. The risk at

the offshore section is higher than the maximum acceptable individual risk criteria of 10-6

/year,

but this risk criterion is only applicable for onshore pipelines. The societal risk is below the target

criteria.

DET NORSKE VERITAS


MANAGING RISK




11 CO2 OFFLOADING AT A SINGLE POINT MOORING SYSTEM

11.1 Introduction

The seagoing vessels will transport the liquid CO2 from the CO2 terminal in the Port of

Rotterdam to the permanent offshore storage sites. These storage sites could be depleted gas

fields or oil fields still in production where the CO2 will be used for EOR. The seagoing vessel

will discharge via an offshore infrastructure Single Point Mooring (SPM) system that links the

vessel to the sub sea completion/template (see example of mooring ship to SPM in Figure 11-1).

Figure 11-1: Example of mooring ship to SPM (courtesy of SBM Offshore)

The permanent storage sites are located offshore which means that different safety legislation is

applicable than for the onshore activities. For the onshore activities the risks assessments focus

on the risk to external population such as towns and offices. For offshore installations no onshore

external population is present and since it is envisaged to have an unmanned tower no third party

persons will be present and therefore risk is not calculated (as risk contours are related to third

party persons)

The Dutch statutory regulations applicable to mineral exploration, extraction, storage and

transport of minerals are handled in the Mining Act, the Mining Decree and Mining Regulations.

Health, safety and environmental legislation and regulations are applicable as well. The

legislation requires the duty holder (i.e. the owner or operator) for each fixed and mobile

installation to prepare a safety case, which must be accepted by the State Supervision of Mines, in

DET NORSKE VERITAS


MANAGING RISK




Dutch “Staatstoezicht op de Mijnen” (SodM), before the installation can be operated on the

Dutch Continental Shelf. The duty holder must demonstrate in the safety case that:

All hazards with the potential to cause a major accident have been identified;

All major accident risks have been evaluated; and,

Measures have been, or will be, taken to control the major accident risks to ensure

compliance with the relevant statutory provisions

A safety case should address the following hazard:

Process (hydrocarbon) leaks

Blow-out (loss of well control incidents)

Riser and pipeline leaks

Collisions (ship - installation, helicopter-installation)

Occupational hazards

The safety study for the SHE report of the LLSC will calculate and evaluate the effects of some

of the identified hazards. A full safety case is not part of the scope.

11.2 Scenarios

The seagoing vessels will first connect to the SPM via a Hawser after which the flexible riser for

unloading is connected. The connection with the SPM will be done at the front of vessel. The

Hawser prevents the vessel from drifting away, for example when the Dynamic Positioning of the

vessel fails, which could lead to a rupture of the flexible line. The SPM allows the seagoing

vessel to weathervane or position itself in order to be less affected by the weather conditions.

The seagoing vessel is equipped with the following installations for unloading purposes:

Deepwell pumps

Each cargo tank is equipped with a deepwell pump to pump the CO2 from the cargo tanks to

the CO2 booster pumps. The pumps are of vertical, submerged, centrifugal multistage design.

CO2 booster pumps

The CO2 booster pumps will be used to bring the liquid CO2 from deepwell pump discharge

pressure to the required discharge pressure. The required discharge pressure will increase

with the years of operation, starting with 150 barg and ending up to 400 barg.

CO2 heaters

The CO2 heaters will be used to bring the liquid CO2 from cargo tanks temperature to the

required discharge temperature.

CO2 vaporizer

DET NORSKE VERITAS


MANAGING RISK




The CO2 vaporizer will be used to generate CO2 vapor to compensate for the decreasing

liquid levels in the cargo tanks during unloading. Without (sufficient flow of) vapor, the tank

pressure would decrease, causing solidification of the CO2 in the cargo tanks. Because the

CO2 vaporizer will be used simultaneously with the CO2 heater, these functions cannot be

combined in one heat exchanger.

Figure 11-2: Side view of CO2 seagoing vessel (Courtesy of Ulstein Sea of Solutions)

It was decided to calculate the consequences of certain failure scenarios at the flexible line used

for the unloading of the seagoing vessel. The unloading rate of the vessel is 450 kg/s, the system

is equipped with an ESD system which automatically stops the pumping and closes the safety

valves when the temperature/pressure is out of range. The maximum unloading pressure of 400

barg was assumed for the consequence calculations.

The following leak sizes have been modeled for the failure scenarios: 5 mm, 20 mm, 50 mm and

a line rupture of the flexible during unloading of the seagoing vessel. The failure scenarios of the

flexible line have been modeled at the front of the seagoing vessel at the forecastle deck height of

the vessel (23.8 meters). The minimum draught (vertical distance between the waterline and the

bottom of the hull) of the vessel is 6.23 meters and the maximum is 11.23 meters. For the

consequence calculations a release of the flexible line at the height forecastle deck of 12 meters

from the water line was assumed.





The releases are directed horizontally and the CO2 cloud is dispersed horizontally before loosing

his momentum after which the cloud disperses downwards because the density of CO2 is higher

than air. This is displayed in Figure 11-3 showing the side view of the CO2 jet due to the rupture

of the flexible line.

It is important to note that these maximum concentration distances are not sustained for such a

long time because of the ESD system and, when the ESD fails, the maximum pumping capacities

of the booster pumps.

DET NORSKE VERITAS


MANAGING RISK




Figure 11-3: Side view of a rupture of the flexible line

The largest effect zones are generated by the line rupture scenario and reaches up to 100 meters

for dangerous CO2 concentrations (50,000 ppm). Figure 11-4 displays the effect zone (top view)

at the release height corresponding to the forecasted deck height of the vessel. The circle

represents the effect zone but than for all wind directions. Figure 11-5 displays for the same

scenario the effect zone at the height of the main deck of the vessel. Because the main deck is 5.6

meters lower only the alarm value is reached.

DET NORSKE VERITAS


MANAGING RISK




Figure 11-4: Top view of the effect zones at the forecasted deck height of the vessel (23.8 m)

Figure 11-5: Top view of the effect zones at the main deck height of the vessel (18.2 m)

DET NORSKE VERITAS


MANAGING RISK




Table 11-1 and Table 11-2 present the maximum concentration distances for the different leak

sizes. Table 11-1 lists how far certain CO2 concentrations levels (27,000 ppm, 50,000 ppm and

100,000 ppm) will reach at the release height corresponding to the forecasted deck height of the

vessel and Table 11-2 at the height of the main deck of the vessel.

Table 11-1: Concentration distances at the forecastle deck height

Leak size (mm) F 1.5 m/s D 5 m/s

27,000 ppm 50,000 ppm 100,000 ppm 27,000 ppm 50,000 ppm 100,000 ppm

5 13 7.8 4.2 12.3 7.5 4.2

20 59 30 16 46 29 16

50 115 73 43 100 68 41

>75 157 100 58 144 92 55

Table 11-2: Concentration distances at the main deck height

Leak size (mm) F 1.5 m/s D 5 m/s

27,000 ppm 50,000 ppm 100,000 ppm 27,000 ppm 50,000 ppm 100,000 ppm

5 - - - - - -

20 - - - - - -

50 63 - - 26 - -

>75 125 - - 98 - -

11.4 Conclusions

In this section the consequences (different concentration levels) have been calculated for the LOC

scenarios for the flexible line during unloading of the seagoing vessel.

Dangerous CO2 concentrations (50,000 ppm) for a 30 minutes exposure time can reach up to

100 meters at the forecastle deck height of the vessel due to a LOC of the flexible line.

Dangerous CO2 concentrations (50,000 ppm) for a 30 minutes exposure time will not reach

the main deck for the calculated LOC scenarios. At the main deck a 27,500 ppm

concentration can still be reached which is the threshold value for dangerous concentrations.

A possible platform will be located 1 nautical mile from the SPM (due to nautical safety

reasons) which means that no dangerous CO2 concentrations (50,000 ppm) can reach a

possible platform.

DET NORSKE VERITAS


MANAGING RISK




12 FINAL CONCLUSIONS

The safety study simulated the LOC scenarios (e.g. leak of a pipeline) for the different LLSC

activities. The table below presents the maximum hazardous effect distances, the 1% lethality

distance and the maximum risk levels for the different activities.

The maximum effect distance of a certain LOC scenarios is the maximum distance where a CO2

concentration of 50,000 ppm could occur. The CO2 concentration of 50,000 ppm is the

concentration where 1% of the humans exposed for 30 minutes are expected to die. However, the

concentrations at the maximum effect distance are, most of the time, not sustained for such a long

time.

Therefore the lethality distances are calculated. The lethality distance of a certain LOC scenario

is determined by calculating the dose at a specific location and using this as input for the CO2

probit function to calculate the fatalities. The dose is a combination of concentration and

exposure time. The 1% lethality distance, presented in the table below, is the distance where 1%

of the humans are expected to die.

The individual risk is the risk of a fatality at a specific location when a person would be present at

that location 100% of the time. The individual risk is calculated by combining the risks of all

identified LOC scenario of an activity, which means that the individual risk presents the total risk

of an activity. The risk of a LOC scenario is a combination of the effects and the probability of

that scenario to occur.

Activity Maximum effect distance

(m)

1% Lethality distance

(m)

Maximum individual

risk (per year)

CO2 emitter terminal 540 280 10-5

Barges 780 510 10-8

Low pressure pipeline 440 380 10-7

CO2 terminal in Rotterdam 680 680 10-5

Seagoing vessels 950 710 -

High pressure pipeline 1980 740 10-6

CO2 offloading offshore 100 - -

The results show that the maximum 1% lethality distances of the activities is in the range of 280

meters up to 740 meters from the location of the accidental CO2 release. This means that the

different activities might affect persons present in the direct vicinity. However, these distances do

not say anything of the risk of the activities.

The individual risk levels appear to be the highest in the direct vicinity of the terminals, which is

caused by the process installations and the (un)loading activities over there. In the direct vicinity

of the terminals no vulnerable objects, such as housing, should be present and this is also not the

case. The CO2 transportation activities do not result in onshore risk levels higher than 10-7

per

year.

Based on the results it can be concluded that all of the CO2 activities could pose an effect on the

direct vicinity when an unintentional release occurs. However, the corresponding risk levels

appear to be below the Dutch risk criteria. Therefore it can be stated that the safety risks

DET NORSKE VERITAS


MANAGING RISK




associated with the Liquid Logistics Shipping Concept is acceptable for all of the considered

activities.

This means that, besides designing and operating according to industry standards / practice, no

extra mitigations measures are needed to reduce the risk for the activities.

DET NORSKE VERITAS


MANAGING RISK




13 REFERENCES

/1/ Evaluation of the acute toxicity of CO2, RIVM, October 2009

/2/

U.S. Environmental Protection Agency, Carbon Dioxide as a Fire Suppressant:

Examining the Risks, February 2000

(http://www.epa.gov/Ozone/snap/fire/co2/co2report.pdf)

/3/ Veiligheidsanalyse Ondergrondse Opslag van CO2 in Barendrecht, Tebodin, October

2008.

/4/ Vragen over CO2 modellering, Letter RIVM / Centrum Externe Veiligheid to DCMR

Milieudienst Rijnmond, 100/09 CEVSpo/mva-2440, April 2009

/5/ Metz, B., Davidson, O., de Coninck, H. C., Loos, M., and Meyer, L. A. (eds.), IPCC,

2005: IPCC Special Report on Carbon Dioxide Capture and Storage. Prepared by

Working Group III of the Intergovernmental Panel on Climate Change, Cambridge

University Press, Cambridge, United Kingdom and New York, NY, USA

/6/ The International Energy Agency Greenhouse Gas R&D Programme

/7/ Technical guideline on hazard analysis for onshore carbon capture installations and

onshore pipelines, 1st edition, September 2010, Energy Institute, London

/8/ Clayton, W.E., and Griffin, M.L., Catastrophic Failure of a Liquid Carbon Dioxide

Storage Vessel, Process Safety Progress, 13, 1994: pp.202-209

/9/ Pettersen, J., Experimental study on boiling liquid expansion in a CO2 vessel, 5th IIR

Gustav Lorentzen Conference on Natural Working Fluids, Guangzhou, China,

September 2002

/10/ DNV Report 2008-1993, Mapping of potential HSE issues related to large-scale

capture, transport and storage of CO2 Report for the Norwegian Pertoleum Safety

Authority, rev02, 21.01.2009. (Available at: www.ptil.no)

/11/ Unique Rescue Problem In Germany; http://firegeezer.com/2008/08/17/unique-

rescueproblem-in-germany/

/12/ Carbon Dioxide (CO2) Pipelines for Carbon Sequestration: Emerging Policy Issues,

CRC Report for Congress, 2008

/13/ Office of Pipeline Safety (OPS) within the U.S. Department of Transportation, Pipeline

and Hazardous Materials Safety Administration (http://ops.dot.gov/stats/IA98.htm)

/14/ Gale, J. and Davidson, J. Transmission of CO2—safety and economic considerations,

Energy, 29, 2004: pp.1319-1328

/15/ Barrie, J., Brown, K., Hatcher, P.R. and Schellhase, H.U. Carbon dioxide pipelines: A

preliminary review of design and risk, Greenhouse Gas Control Technologies, vol. 1,

2005: pp. 315-320

/16/ Lake Nyos degassing project (http://pagesperso-orange.fr/mhalb/)

/17/ IChemE, 1992. Nomenclature for Hazard and Risk Assessment in the Process

Industries, Rugby: Institution of Chemical Engineers.

/18/ Circulaire „Zonering langs hogedruk aardgas-transportleidingen‟, VROM, 1984

/19/ Circulaire „Bekendmaking van beleid ten behoeve van de zonering langs

transportleidingen voor brandbare vloeistoffen van de K1-, K2- K3-categorie‟, VROM,

DET NORSKE VERITAS


MANAGING RISK




1991

/20/ Reference Manual Bevi Risk Assessments version 3.1, RIVM, 2009.

/21/ Protocol Risicoanalyse zee- en binnenvaart, DNV, AVIV, 2000.

/22/ Consequence modelling, International Association of Oil & Gas Producers, report 434 –

7, March 2010

/23/ Very Large Deep-Set Bubble Plumes From Broken Gas Pipelines, Petroleumtilsynet,

report 6201, Torstein K. Fanneløp og Marco Bettelini, 18th November 2007

/24/ Veiligheidsstudie LNG scheepstransporten ten behoeve van de GATE LNG import

terminal in het Rotterdamse havengebied, Marin, april 2006.

/25/ Risicoatlas hoofdvaarwegen Nederland, AVIV, februari 2003.

/26/ Richtlijn voor kwantitatieve risicoanalyse, PGS3 / Purple Book, 2000.

DET NORSKE VERITAS


MANAGING RISK




APPENDIX 1

CONSEQUENCE RESULTS LOW PRESSURE PIPELINE

- o0o -

DET NORSKE VERITAS


MANAGING RISK




LOC of an aboveground LP pipeline

The figures below show the consequences of a rupture and leak of an aboveground pipeline.

Figure A.1-1: Concentration profile of aboveground pipeline rupture

Figure A.1-1 shows the maximum concentration profile of an aboveground pipeline rupture. The

CO2 jet is directed horizontally and therefore dangerous CO2 concentrations extend further than

only the release location. Dangerous concentrations (50,000 ppm) can reach up to 140 meters of

the release location (130 meters for D5).

Figure A.1-2: Maximum lethality footprint of aboveground pipeline rupture

DET NORSKE VERITAS


MANAGING RISK




The lethality footprint in Figure A.1-2 confirms the distance seen in Figure A.1-1. The maximum

distance from the release location at which fatalities can occur is at 90 meters (83 meters for D5).

Figure A.1-3: Concentration profile of aboveground pipeline leak (50 mm)

Figure A.1-3 displays the maximum concentration profile of a 50 mm leak. The leak has of

course a lower discharge than a rupture and therefore the CO2 cloud is sooner diluted to harmless

concentrations. Dangerous concentrations (50,000 ppm) can reach up to 17 meters of the release

location (15.5 meters for D5).

Figure A.1-4: Maximum lethality footprint of aboveground pipeline leak (50 mm)

The lethality footprint, see Figure A.1-4, reaches up to 15.5 meters (14 meters for D5).

DET NORSKE VERITAS


MANAGING RISK




LOC of an underground LP pipeline

The figures below show the consequences of a rupture and leak of an underground pipeline.

Figure A.1-5: Concentration profile of underground pipeline rupture

Figure A.1-5 shows the maximum concentration profile of a rupture. The CO2 jet is directed

vertically, after losing momentum the dispersion follows the wind direction. CO2 is heavier than

air but due to dilution with warmer air the CO2 cloud is not sufficiently heavy to reach the ground

during the dispersion phase.

Figure A.1-6: Maximum lethality footprint of underground pipeline rupture

DET NORSKE VERITAS


MANAGING RISK




Lethal CO2 concentrations are only located at the release location which is confirmed by the

lethality footprint in Figure A.1-6. The maximum distance from the release location at which

fatalities can occur is at 1.4 meters (same as for D5).

Figure A.1-7: Concentration profile of underground pipeline leak (20 mm)



concentrations. The lethality footprint is not shown in the report but the maximum distance from

the release location at which fatalities can occur is lower than 0.5 meters (both for F1.5 as well as

D5).

LOC of an underground LP pipeline crossing a waterway

The figures below show the consequences of a rupture and leak of an underground pipeline

crossing the waterways Hartelkanaal and Dintelhaven.

DET NORSKE VERITAS


MANAGING RISK




Figure A.1-8: Maximum concentration footprint of pipeline rupture crossing a waterway

Figure A.1-9: Maximum lethality footprint of pipeline rupture crossing a waterway

Figure A.1-8 shows the maximum concentration footprint of a pipeline rupture under a waterway.

The CO2 jet is directed vertically and has a low momentum. Due to the low momentum the CO2

jet is lower than the CO2 jet for the underground pipeline. Therefore dangerous CO2

concentrations (50,000 ppm) extend further, they can reach up to 440 meters of the release

location (186 meters for D5). This is confirmed by the lethality footprint in Figure A.1-9. The

maximum distance from the release location at which fatalities can occur is at around 380 meters

(155 meters for D5).

DET NORSKE VERITAS


MANAGING RISK




Figure A.1-10: Concentration profile of pipeline leak (20 mm) crossing a waterway



concentrations. The dangerous CO2 concentrations (50,000 ppm) can reach up to 22 meters of the

release location (14 meters for D5). Lethality calculations are done at a height of 1 meter.

Dangerous CO2 concentrations at a height of 1 meter are only localized at the release location and

therefore no lethality contour could be generated.

LOC of a LP pipeline in tunnel

The figures below show the consequences of a rupture of a pipeline located in a tunnel.

DET NORSKE VERITAS


MANAGING RISK




Figure A.1-11: Maximum concentration footprint of pipeline rupture in a tunnel

Figure A.1-11 shows the maximum concentration footprint of a pipeline rupture in a tunnel. The

CO2 jet is directed vertically and has a low momentum. Due to the low momentum the CO2 jet is

lower than the CO2 jet for the underground pipeline. Therefore dangerous CO2 concentrations

(50,000 ppm) extend further, they can reach up to 420 meters of the release location (245 meters

for D5).

Figure A.1-12: Maximum lethality footprint of pipeline rupture in a tunnel

The lethality footprint in Figure A.1-12 confirms the distances seen in Figure A.1-11. The



DET NORSKE VERITAS


MANAGING RISK




APPENDIX 2

CONSEQUENCE RESULTS HIGH PRESSURE PIPELINE

- o0o -

DET NORSKE VERITAS


MANAGING RISK




LOC of an aboveground HP pipeline

The figures below show the consequences of a rupture and leak of an aboveground HP pipeline.

Figure A.2-1: Concentration profile of aboveground HP pipeline rupture

Figure A.2-1 shows the maximum concentration profile of an aboveground pipeline rupture. The

CO2 jet is directed horizontally and therefore dangerous CO2 concentrations extend further than

only the release location. Dangerous concentrations (50,000 ppm) can reach up to 300 meters of

the release location (285 meters for D5).

Figure A.2-2: Maximum lethality footprint of aboveground HP pipeline rupture

The lethality footprint in Figure A.2-2 confirms the distance in Figure A.2-1. The maximum

distance from the release location at which fatalities can occur is at 156 meters (145 meters for

D5).

DET NORSKE VERITAS


MANAGING RISK




Figure A.2-3: Concentration profile of aboveground HP pipeline leak (50 mm)



concentrations. Dangerous concentrations (50,000 ppm) can reach up to 44 meters of the release

location (40 meters for D5).

Figure A.2-4: Maximum lethality footprint of aboveground HP pipeline leak (50 mm)

The lethality footprint, see Figure A.2-4, reaches up to 37 meters (35 meters for D5).

DET NORSKE VERITAS


MANAGING RISK




LOC of an underground HP pipeline

The figures below show the consequences of a rupture and leak of an underground HP pipeline.

Figure A.2-5: Concentration profile of underground HP pipeline rupture

Figure A.2-5 shows the maximum concentration profile of a rupture. The CO2 jet is directed

vertically, after losing momentum the dispersion follows the wind direction. CO2 is heavier than

air but due to dilution with warmer air the CO2 cloud is not sufficiently heavy to reach the ground

during the dispersion phase. Lethal CO2 concentrations are thus only located at the release

location which is confirmed by the lethality footprint in Figure A.2-6.

Figure A.2-6: Maximum lethality footprint of underground HP pipeline rupture

The maximum distance from the release location at which fatalities can occur is at 8 meters (both

for F1.5 and for D5).

DET NORSKE VERITAS


MANAGING RISK




Figure A.2-7: Concentration profile of underground HP pipeline leak (20 mm)


course a lower discharge rate than a rupture and therefore the CO2 cloud is sooner diluted to

harmless concentrations. The lethality footprint is not shown in the report but the maximum

distance from the release location at which fatalities can occur is less than 0.5 meters (same as for

D5).

LOC of an underground HP pipeline crossing a waterway

The figures below show the consequences of a rupture and leak of an underground HP pipeline

crossing the Yangtze harbor and the Maasgeul.

Figure A.2-8: Maximum concentration footprint of pipeline rupture crossing a waterway

DET NORSKE VERITAS


MANAGING RISK




Figure A.2-8 shows the maximum concentration footprint of a pipeline rupture under a waterway.

The CO2 jet is directed vertically and has a low momentum. Due to the low momentum

dangerous CO2 concentrations (50,000 ppm) extend further than for an underground pipeline,

they can reach up to 1980 meters of the release location (355 meters for D5).

Figure A.2-9: Maximum lethality footprint of pipeline rupture crossing a waterway

The lethality footprint in Figure A.2-9 confirms the distance found in Figure A.2-8. The



Figure A.2-10: Concentration profile of pipeline leak (20 mm) crossing a waterway

DET NORSKE VERITAS


MANAGING RISK






concentrations. The dangerous CO2 concentrations (50,000 ppm) can reach up to 50 meters of the

release location (28 meters for D5). Lethality calculations are done at a height of 1 meter.

Dangerous CO2 concentrations at a height of 1 meter are only localized at the release location and

therefore no lethality contour could be generated.

Det Norske Veritas:

Det Norske Veritas (DNV) is a leading, independent provider of services for managing risk with a global presence and a network of 300 offices in 100 different countries. DNV’s objective is to safeguard life, property and the environment. DNV assists its customers in managing risk by providing three categories of service: classification, certification and consultancy. Since establishment as an independent foundation in 1864, DNV has become an internationally recognised provider of technical and managerial consultancy services and one of the world’s leading classification societies. This means continuously developing new approaches to health, safety, quality and environmental management, so businesses can run smoothly in a world full of surprises.

Global impact for a safe and sustainable future:

Learn more on www.dnv.com

Documents

Final Public Report Safety study for Liquid Logistics Shipping Concepthub.globalccsinstitute.com/sites/default/files/... · 2013-08-22 · Safety study for Liquid Logistics Shipping