Assignment 2 Prepare an outline specification for an LNG plant located at Vasilikos, Cyprus

MOE 506 LNG Processing, Storage, Transport, Re-gasification, Distribution and Usage

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Assignment 2

Prepare an outline specification for an LNG

plant located at Vasilikos, Cyprus

Authors: Supervisor:

Nikolaos G. Felessakis Dr Richard J Barnes

(8653)


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Introduction ............................................................................................................................................. 4

1. LNG plant process and capacity ................................................................................................. 5

1.1 Introduction to LNG processing ......................................................................................... 5

1.2 Feed Gas Processing ............................................................................................................... 7

1.2.1 Inlet Separation and Treatment System .................................................................................. 7

1.2.2 Acid Gas Removal System .............................................................................................................. 8

1.2.2.1 Acid Gas Removal ..................................................................................................................................... 8

1.2.3 Dehydration System ......................................................................................................................... 8

1.2.4 Mercury Removal System .............................................................................................................. 9

1.3 Liquefaction .............................................................................................................................. 9

1.3.1 Liquefaction System ......................................................................................................................... 9

1.3.2 Refrigeration System .................................................................................................................... 10

1.4 Sources of gas, design rate and project life .................................................................. 10

2. Pipeline connection ..................................................................................................................... 12

2.1 Pipeline Technical Characteristics ................................................................................. 12

2.2 Coatings .................................................................................................................................... 13

2.3 Pipeline calculations ............................................................................................................ 13

2.3.1 Outlet pressure ................................................................................................................................ 13


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2.3.2 Wall thickness .................................................................................................................................. 14

3. LNG export facilities and loading frequency ....................................................................... 16

3.1 LNG Jetty Type ........................................................................................................................ 16

3.2 The loading arms .................................................................................................................. 17

3.2.1 LNG serve and uploading time ................................................................................................. 17

4. LNG storage tank size, type and quantity ............................................................................. 18

5. Bibliography .................................................................................................................................. 20

TABLE 1.4-‐1PRODUCTION VOLUME RELATED WITH RESOURCES AND THE SIZE OF THE LNG PLANT ............................... 11

TABLE 2.3-‐1 Q FLOW RATE CALCULATIONS ................................................................................................................................. 14

TABLE 2.3-‐2 PIPE OUTLET WALL THICKNESS .............................................................................................................................. 15


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Introduction

This project aims to describe the outline of Liquefied natural gas (LNG) plant in

Vasilikos area from the potential reserves of the Aphrodite field.


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1. LNG plant process and capacity

The natural gas is inherently a domestic product. As gas, the hydrocarbon must

be transported by pipeline, which reduces the number of recipients. Liquefied

Natural Gas (LNG) was developed in 1964 as a solution to this problem. That

solution entails the following: LNG gas is being liquefied and transported

internationally via tankers and then regasified into its original state for distribution

and sale1.

1.1 Introduction to LNG processing

There is no typical or standard LNG plant. The major elements that are found in

most LNG plants include:

− Feed gas Processing

• Inlet Separation and treatment

• Acid gas removal

• Dehydration and Mercury removal

− Liquefaction

• Refrigeration System

− Fractionation

− Plant Utilities

• Hot Oil System

− Storage

The LNG Plant will receive gas from the LNG Project Gas Pipeline, treat it and then

liquefy it using refrigerants. Figure 1-1 illustrates the simplified process flow

diagram for the plant.

1 http://www.rigzone.com/training/insight.asp?i_id=322


6 Figure 1-2 Simplified process flow diagram for the plant.


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Specifically, the LNG Plant will:

• Heat the incoming gas from the pipeline,

• Reduce its pressure, and remove any liquids entrained with the gas,

• Remove acid gas, residual moisture and mercury,

• Liquefy the feed gas and

• Fractionate the hydrocarbon liquids produced during the liquefaction

process into condensate (pentane and heavier hydrocarbons) for export.

1.2 Feed Gas Processing

1.2.1 Inlet Separation and Treatment System

The inlet facilities at the LNG Plant will receive a single-phase gas from the

Pipeline network at a pressure of 6,750 kPag and a temperature of 30°C. The gas

will have been conditioned to a water and hydrocarbon dew point of 5°C at the

Hides Gas Conditioning Plant (Exxon Mobil, 2013)

The hot oil system will heat the gas to prevent hydrate formation and to meet the

amine absorber feed gas temperature requirement. The warmed gas will be

depressurized and flow to the inlet feed gas separator, which will remove small

liquid slugs. The inlet liquids separator will receive these liquids (if present) and

send the hydrocarbons to fractionation for processing into condensate. The

produced water stream will be sent to the wastewater treatment system for

disposal.

Feed gas from the inlet feed gas separator will be metered ahead of final

treatment before liquefaction to remove acid gas, residual water and traces of

mercury.


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1.2.2 Acid Gas Removal System

Impurities in a gas stream, such as hydrogen sulfide and carbon dioxide, are

collectively referred to as acid gases. The acid gas as the carbon dioxide, it can

be freeze at cryogenic liquefaction temperatures and thereby block the natural

gas flow path. An amine solvent (amine mixed with water) will be used to remove

acid gas, as follows(idid).

1.2.2.1 Acid Gas Removal

Feed gas warmed to approximately 35°C from the metering station enters the

bottom of the amine absorber. The amine solvent enters the absorber near the

top and flows counter-current against the gas being treated, so that the freshest

solvent contacts the cleanest gas first. The solvent progressively absorbs the acid

gases and exits the bottom of the amine absorber.

The treated feed gas then flows from the top of the amine absorber to the

dehydration system. Sweetened gas can also be used as high pressure start-up

fuel gas(idid).

1.2.3 Dehydration System

The gas leaving the acid gas removal system will be saturated with water. The

dehydration system will dry the gas down to less than 0.1 ppm(v) of water to

prevent ice (hydrates) forming in the downstream cryogenic equipment. A

propane refrigerant cools the feed gas to 25°C and condenses most of the water

vapor. The dehydration feed separator returns the condensed water and solvent

carryover to the acid gas removal system as make-up.

Regeneration will be achieved with a gas stream. This regeneration gas will be

heated by the hot oil system to approximately 230°C. When a bed is

regenerating, the hot regeneration gas stream enters at the bottom of the drier

and exits at the top. The water released during regeneration will normally be

directed to the wastewater treatment system or used as make-up water for the

acid gas removal system(idid).


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1.2.4 Mercury Removal System

Elemental mercury corrodes aluminium, and even very low traces must be

removed to prevent damage to the cryogenic heat exchangers. The mercury

removal system will pass gas from the dehydration system through an absorber of

non-regenerative, sulfur-impregnated, activated carbon, which will chemically fix

elemental mercury as a non-volatile mercury sulfide.

After this procedure the mercury levels in the feed gas are so low that the

adsorbent may not need to be replaced during the life of the project(idid).

1.3 Liquefaction

Liquefaction uses the feed gas to below the methane boiling point of around -

161°C. At this temperature, the gas liquefies to 1/600th of its original volume.

1.3.1 Liquefaction System

The liquefaction system in an LNG train comprises propane coolers, a heavy-

hydrocarbon removal column, and cryogenic heat exchangers. Propane coolers

will cool the feed gas from the mercury removal system. The coolers liquefy the

heavier hydrocarbons, which then flow to a heavy-hydrocarbon removal

column. Heat and pressure will be used to separate the heavier hydrocarbons

from the feed gas stream in the column. These heavier hydrocarbons (ethane,

propane, butane and heavier components) will exit the bottom of the column.

The vapors will exit the top of the column and flow to the main cryogenic heat

exchanger.

The LNG will be produced at approximately 800 t/hr. The flashing process loses

some of the LNG as a vapor, which will be warmed and then compressed. Some

of this gas will be used to regenerate the molecular sieve driers in the

dehydration system before being sent to the high-pressure fuel gas system.


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The LNG from the liquefaction system will be pumped to the LNG storage tanks

(idid).

1.3.2 Refrigeration System

The refrigeration system cools and pressurises the refrigerants used in the

liquefaction system. The refrigeration system will use closed-loop, refrigerant

circuits to provide the low-temperature refrigerants. The refrigerants will be used

to liquefy and sub-cool the feed gas in the cryogenic heat exchangers(idid).

1.4 Sources of gas, design rate and project life

The natural gas discovery in Cyprus Block 12 has estimated gross mean resources

of 5 trillion cubic feet (Tcf)2. Furthermore the available gas will depend first on

how much is used for domestic consumption.

𝐺𝑎𝑠 𝑁𝑒𝑒𝑑𝑒𝑑 =𝑃𝑟𝑜𝑑𝑢𝑐𝑡𝑖𝑜𝑛𝑃𝑜𝑤𝑒𝑟

𝐻𝑒𝑎𝑡𝑖𝑛𝑔 𝑣𝑎𝑙𝑢𝑒 𝑥 𝐶𝑦𝑐𝑙𝑒 𝐸𝑓𝑓𝑖𝑐𝑖𝑒𝑛𝑐𝑦

Production Power (MWh)3 3000000

Heating value (MJ/ m3)4 39.2 Cycle efficiency (%)5 37.5

𝐺𝑎𝑠 𝑁𝑒𝑒𝑑𝑒𝑑 = 0,7578 𝑥 10!𝑚!

𝑦

That means 19 bcm will be used from 2019 until 2044. This reduces the amount of

gas available from 141,5 bcm6 to 122,5 bcm.

2 Source: http://www.nobleenergyinc.com/exploration/recent-discoveries-130.html 3 http://www.dsm.org.cy/nqcontent.cfm?a_id=2741&tt=graphic&startdt=20%2F05%2F2010&type=15&submit=Go 4 Courses Material Barns 2014 5 http://www.eac.com.cy/EN/Pages/Home.aspx 6 http://www.convertunits.com/from/trillion+cubic+feet/to/billion+cubic+metre


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Field Reserves Tcf 5

Life of LNG plant years 25

Liquefaction efficiency 0.85

1 m3 of LNG 609 m3 of NG produce

mtpa to million m3 x 0,46

Table 1.4-1Production Volume related with resources and the size of the LNG plant

[((7,062– 0,7578) x 109 (m3/y)) x 0,85] / 609 = 8,8 x 106 (m3/year) x 0,46 = 4mtpa


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2. Pipeline connection

Another major part of the LNG procedure is the feed process from the reserve to

the LNG plant through the pipeline connection. The offshore pipeline

construction is related with the environment parameters of the geographical

position of the reserve. This parameters are the distance between reserve and

LNG plant, the sea depth that is related with the pressure, and the temperature.

This parameters define the characteristics of the pipeline such as the Diameter,

in/out wall thickness and the material.

2.1 Pipeline Technical Characteristics

The Aphrodite-Vasilikos pipeline connection has an offshore distance

approximately 200km in 2000m sea depth. These conditions are similar with the

‘Blue Stream’ that provide a conduit for export of Russian gas directly to Turkey

with an offshore distance up to 398 km and 2150 m sea depth7.

Because of this similarity we can assume that we can use the same pipeline data

such as:

− Diameter: 24inc (=609.6 mm)

− Pressure: 250 bar in a sea depth of 2150m

− Temperature: -10ºC to +55ºC

− 32 mm wall thickness

− Flow rate ~ 2.5m/s and

− Material type carbon steel with outer coating of concrete (Shell, 2010).

7 sources: Natural gas prices from index. mundi; LNG prices from Reuters; pipeline costs from Pete Wallace, Tractebel Engineering; LNG plant cost from Minister Sylikiotis; distances from Block 12 to Vassiliko from DEFA; distance from Cyprus to Greece from DEPA; pipeline depth to Greece from Quantum Energy figures on electricity cable.


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2.2 Coatings

Probably, the best choice for the anti-corrosion coating is application used in the

Blue Stream. After several tests the best solution for pipeline protection in the

extreme environment of 2000m underwater depth is a three layer polypropylene

coating consisting of a first layer of fusion bonded epoxy, a second layer of

polypropylene adhesive and an outer layer of polypropylene.

2.3 Pipeline calculations

2.3.1 Outlet pressure

Regarding the size of pipeline that brings the NG to shore, several factors should

be taken into account. To calculate the size of the pipe the AGA Equation

measuring a pipe’s pressure was used:

For the estimation of the pipeline size we did not have the necessary information

for the several factors and thus, it was based on the following assumption:

5(TCF) / [25(years) x 365(days)] = 547,945.21 (SCFD)

[547,945.21 (SCFD) x 365(days) x 35,314] / 1000 = 7,062,800,000 (S m3/year)

Q = 7,062,800,000( S m3) / 365days) = 19,350,136.99 m3 /day


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Q flow rate at base conditions (m3/day) 19,350,136.99 Calculated

Ts: standard temperature (K) 288.9

Curse Material Dr Richard J Barnes 2014

Ps: standard pressure (kPa(a)) 101.56

E: pipeline efficiency 1

ε: pipe roughness (mm) 0.004

T: average flowing temperature (K) 303

Z: Compressibility factor 0.93

d: pipe internal diameter (mm) 711.2 Sources from the Snohviti

offshore fields until the

Hammerfest LNG plant

P1: inlet pressure (kPa(g)) 15,000

γ: gas specific gravity 0.7341

P2: outlet pressure (kPa(g)) 909,651,183 Calculated

L: pipeline length (m) 184000 Reserve Data

Table 2.3-1 Q flow rate calculations

The Outlet pressure is 9096,51183 kPa (=90,96 bar)

2.3.2 Wall thickness

The wall thickness is given from the following equation :

𝑇𝑚 =𝑃𝑑𝑜2𝑆𝐹𝐸𝑇

+ 𝑇𝑐


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Tm: wall thickness (mm) 31.98315974

P: Design pressure ((kPa(g)) 17000 Under water Pressure at

1689m do: outside diameter (mm) 609.6 From DEPA

S: minimum yield strength (kPa) 248305.11 http://www.hse.gov.uk/research/rrpdf/rr105.pdf

F: Construction type design factor 0.72

Courses Material Barnes 2014

E: Longitudinal joint factor 1 T: temperature rating (1,0) 1 Tc: corrosion allowance (mm) 3

Table 2.3-2 Pipe outlet wall thickness


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3. LNG export facilities and loading frequency

For designing the export facilities the size of the LNG fleet should be considered.

According to the PFC energy

global Services the 62% of the

LNG vessel until 2012 has an

average capacity of 138.000

bcm. Designing the LNG

Storage of Vasilikos with

180.000 bcm will be able to

serve the 81% of the LNG

fleet. Furthermore, it is

reasonable to construct two

storage tank getting the advantage of loading one tank from the liquefaction

process and the same time unloading a LNG vessel from the other tank.

Considering the above two tanks with total capacity of 360.000 bcm are able to

serve even the bigger LNG vessel with 260.000 bcm upload capacity.

3.1 LNG Jetty Type

The LNG Jetty connecting the LNG storage tanks

and condensate storage tanks with the LNG and

condensate export berths.

The Jetty stricture include:

− LNG loading and vapor return lines,

− Condensate loading lines,

− Utilities,

− Jetty head operations platform.

− A roadway capable of accommodating

trucks carrying heavy loads, ambulances,

small cranes, and pedestrian traffic.

Table 3-1 Global LNG Fleet by Capacity, 2012 Sources: PFC Energy Global LNG Service

Figure 3-1 LNG jetty


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3.2 The loading arms

The jetty head will be fitted

with unloading arms to

connect the ships pipework to

the jetty pipework. The

loading arms typically consist

articulated pipe structures

that can be maneuvered to

allow the connection of the

ships loading/unloading

pipework to the shore jetty’s

pipelines structure.

The loading arms support and direct the vapor return or the loading lines. The two

liquid service loading arms and the dual-purpose liquids or vapor return loading

arm will assume a usual capacity of 5,000 m3/hour. The vapour return loading arm

will have a capacity of 20,350 m3/hr.

3.2.1 LNG serve and uploading time

We assume that an average LNG vessel capacity is 138.000m3. Eventually, only

one jetty is needed to serve a ship with a rate of 5,000 m3/hour and it needs 27,6

hours. If two arms are loading the vessel will be loaded in 13,8 hours.

Number of tanker that can be served per year related with the annual LNG

production are:

8,8 x 106 (m3/year) / 138.000 m3/ship ≅ 64 LNG vessel per year

Figure 3.2-1 Al-Khuwair loading at gate LNG in Netherlands1


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4. LNG storage tank size, type and quantity

The Vasilikos Energy Project proposes to store the LNG under cryogenic conditions

on site at slightly above atmospheric pressure by a system of pressure relief valves

set at 250 bar in double skinned 172,000 m3 LNG Tanks. The inner tank is

constructed of a nickel steel alloy and is designed to hold the LNG. The outer

tank constructed of

reinforced pre-

stressed concrete is

designed to hold the

liquid contents of the

tank in the event of a

leak. The 1m space

between the tanks is

filled with an

insulating material

designed to minimize

heat ingress into the tank. The tanks will be the largest structures on the site at 80

m in diameter and 45 meters high with a domed roofs and a number of valves

and fittings on the tank roof. LNG export pumps will be located within wells inside

the LNG tank. The tank’s concrete floor is likely to be provided with a heating

element in order to prevent water in the ground beneath the tank from freezing

and disturbing the tank foundations. Figure 3.9 below shows the typical tank

layout (Parsons Brinckerhoff Limited, Aeoliki Limited, 2006).

`Figure 4-1 Storage Tanks at Yemen LNG, Balhaf, Yemen1


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Figure 4-2 Full Containment (Steel Roof) LNG Tank8

Tanks themselves will not need any external refrigeration sources as they are

cooled automatically using latent heat (the absorption of heat energy by the

evaporating gas) derived from the LNG boil off gas. The heat flux into the tanks

will be kept to a minimum by insulting both the tanks themselves and the

unloading lines through which the LNG is constantly circulated (ibid).

8 Source Global LNG Sales LNG Import Terminal Cost and Schedule Basics (Gerald Humphrey)


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5. Bibliography

Unsupported source type (ElectronicSource) for source GUP.

Arms of innovation. 2014. [Film] France: dsp an endemol company.

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nology-25213845 [Accessed 04 December 2013].

Bergin, W. & Spearman, E., 2006. Vasilikos Energy Centre Basis of Design

Environmental Assessment. EA. Middlesex: Parsons Brinckerhoff Limited, Aeoliki

Limited.

Bp, 2013. con Fact. [Online] Available at: www.car.gr.

Briggs, et al., 2013. LNG LIQUEFACTION PLANT. In “Poten”, ed. MASTER PLAN OF

THE VASILIKOS AREA. NIcosia: “Poten” & "ALA". p.29.

Chartered , P., 1992. http://www.the-edi.co.uk/. [Online] (7th) Available at:

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http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0C

CsQFjAA&url=http%3A%2F%2Fphx.corporate-

ir.net%2FExternal.File%3Fitem%3DUGFyZW50SUQ9NTM5MDYxfENoaWxkSUQ9MjI4NT

kzfFR5cGU9MQ%3D%3D%26t%3D1&ei=0lduU-

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International Institute for Environment and Development (IIED) , n.d.

http://www.environmental-mainstreaming.org. [Online] Available at:

http://www.environmental-

mainstreaming.org/documents/EM%20Profile%20No%201%20-

%20EIA%20(6%20Oct%2009).pdf.

Kotzot, , Durr, , Coyle, & Caswell, , 2007. LNG LIQUEFACTION — NOT ALL PLANTS

ARE CREATED EQUAL. [Online] KBR Available at:

http://www.kbr.com/Newsroom/Publications/LNG/ [Accessed 2007].

National Centre for Risk Analysis and Options Appraisal Environment Agency,

2002. https://www.gov.uk/. [Online] Environment Agency Available at:

https://www.gov.uk/government/uploads/system/uploads/attachment_data/file

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projects.

Nobole Energy International, 2013. http://www.mcit.gov.cy. [Online] Available at:

http://www.mcit.gov.cy/mcit/mcit.nsf/All/11FFCD876C06B58CC2257C7700255D1

8/$file/04-Vasilikos%20Master%20Plan%202013_Executive%20Summary%20-

%20Eng.pdf [Accessed 1 Octomber 2013].

Managment, E.R., 2001. http://ec.europa.eu/. [Online] Available at:

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[Accessed 19 April 2014].

Paltsev, et al., 2013. Natural Gas Monetization Pathways for Cyprus. Economics of

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Parsons Brinckerhoff Limited, Aeoliki Limited, 2006. VASILIKOS ENERGY CENTRE

BASIS OF DESIGN ENVIRONMENTAL ASSESSMENT. Middlesex: M.W. Kellogg Limited

Kellogg.


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Shell, 2010. Transporting Oil and Gas, What’s in a Barrel of Oil?. [Online] Available

at: www.shell.us/alaska.

Shell, n.d. Prelude FLNG. [Online] Available at:

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au/operations/upstream/prelude.html [Accessed 2 May 2014].

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http://www.eliamep.gr/wp-content/uploads/2014/02/policy-paper.pdf

[Accessed November 2013].

iSource about Shoviet reserve http://www.ivt.ntnu.no/ept/fag/tep4215/innhold/LNG%20Conferences/2007/fscommand/PS7_3_Skjerven_s.pdf

Documents

Assignment 2 Prepare an outline specification for an LNG plant located at Vasilikos, Cyprus