Presentation of Vapour Recovery Systems - M.P. Enggmpengg.com/carbovac_pdf_files/english_VRU_evolution.pdf · Presentation of Vapour Recovery Systems ... Flare gas recovery using

Presentation of Vapour Recovery Systems

By Ties MulderProcess and Implementation Consultant

June 2005

Presentation VRU - June 2005 2/64

• History of Vapour Recovery & Technologies developed

• Worldwide Emission legislation

• Closed circuit European recovery system for truck

• Implementation of Vapour Recovery systems on terminals

• Recovery product, rate, tax refund

• Safety aspects, ATEX, SIL









First systems = thermal destruction (air assisted flare)

First Systems

• Energy consumption : high• Destruction : 97 % efficiency• Maintenance : low


First recovery systems installed in the United States Flare gas recovery using compression and cooling

First Recovery Systems

Separator

Cooler

Compressor

Vapour Inlet

Outlet to Flare

Recovered Liquid

• Energy consumption : high• Emissions : 80 % efficiency• Maintenance : medium


Early 70s : first activated carbon / vacuum system (Rheem Brothers - USA)

Adsorption systems

• Energy consumption : low• Emissions : 80 % efficiency• Maintenance : high

Activated Carbon Filters

Re-absorber

Vacuum Pump

Glycol Separator

Gasoline return

Gasoline supply

Top product vented to atmosphere

Vapour Inlet

Clean air outlet


Deep cooling systems @ -35°C (Edwards - USA)

Deep cooling systems

Vapour Inlet

De-icingheater

Clean Air Outlet

ChillerCoolingElements

Pure Product

• Energy consumption : high• Emissions : < 80 g/m3

• Maintenance : very high


First patent by McGill in 1978 based on Rheem brothers with recycling of absorber top

Evolution of Adsorption systems...

Vacuum Pump

Activated Carbon Filters

Re-absorber

Glycol Separator

Gasoline return

Gasoline supply

Top product returned to inlet

Vapour Inlet

Clean air outlet

• Energy consumption : low• Emissions : 35 g/m3

• Maintenance : high

Replacement of deep cooling by adsorption systems in USA


Since 1980 ’s : Activated carbon / Liquid ring vacuum systems as known today

Evolution of Adsorption systems

Adsorbers

Clean Air Outlet

Vapour Inlet

Purge

Vacuum Pump

Absorber

Absorbents

SeparatorCooler

EG

• Energy consumption : high• Emissions : < 35 g/m3

• Maintenance : high

Suppliers patents in severalEuropean countries


Fear of patent infringement Development of alternative solutions in Europe

Cold absorption system : Coolsorption / KappagiMembrane system : Vaconocore / PreussagActivated carbon + cold re-absorption : KaldairCogeneration : Petro-Plus (Qlear) / SchwelmAbsorption / Adsorption / Absorption : Mc Gill

Introduction by Germany and Switzerland of extremely low emissions Development of complex hydride systems

Cold adsorption + Steam regenerated carbon : CoolsorptionMembrane + Vacuum regenerated carbon : VaconocoreLRVP + Roots blowers : John ZinkThermal balance adsorption : Ties Mulder

Alternative solutions


Cold absorption system

VapourInlet

CleanAirOutlet

Absorbents Inlet

Absorbents Return

Reabsorber

Splitter

Chiller

HeaterAbsorber

Cooler

Nonane Circuit


Membrane system

Evnt. 2 nd Stage

Membrane

Vacuum Pump

Separator

Cooler

Compressor

Vapour Inlet

Clean Air Outlet


Clean Air Outlet

Vac pump

Separator

Heat exchanger

Absorber

Adsorption Filters

Vapour Inlet

Condenser

Absorbents

Thermal Balance Adsorption


Latest developments

Latest developments : Dry screw pumps systems by CarboVac

Re-Absorber Absorbants CirculationDry ScrewVacuum Pump

P

Inlet

Activated Carbon Beds

Outlet

• Energy consumption : low• Emissions : < 10 g/m3

• Maintenance : low

Replacement of glycol systems by dry systems


Activated carbon = highly favourite solution since 1980More than 90% of all recovery systems in the world

In the USA, destruction by combustion still represents 40%But restrictions are coming due to :

New CO2 limitation policies (Kyoto protocol)Adoption by Petroleum Companies (BP, Shell) of internal green policies (engagement to reduce 50% of CO2 emissions)

Replacement of destruction by recovery solutions

Actual situation









VOC effects

VOC emissions impact on the human health (carcinogenic components)pollution of the troposphere (ozone creation)

In Europe, 17 million tons /year of VOC released in the atmospherein 1990.

Implementation of legislation and several regulationsin particular on emissions in hydrocarbon storage and transfer terminals


In the 80ies, 1st legislation : Clean Air Act on VOCEmission limit : 80 g/m3 loaded

In 1982, emission limit reduced to 35 g/m3 loaded (general case) and locally to 10 or 6 g/m3 loaded.

Complex control measurement method to prove compliance.First with balloons and mass balanceLater by using CIM and CEM

USA 1st Clean Air Act


European Directive EC94/63 35 g / m3 of air emitted (often 10 g / m3 is desired - Oslo protocol)3 phases :

1998 : a VRU for all new terminals + terminal > 150 000 tons/year of gasoline2001 : a VRU for terminal > 25 000 tons/year2004 : a VRU for terminal > 10 000 tons/year

Application for fuels with RVP > 276 mbar

TA-Luft 01 in Germany, LRV in SwitzerlandIf emission mass flow > 3 kg/h :

150 mg HC/ m3 of air emitted (20. BImSchG)5 mg / m3 for benzeneMethane is excluded (difficult to recover, only destruction possible by combustion with secondary emissions)

European legislation


In USA : emissions measured as a function of loaded gasolineComplex system required for EPA compliance testMeasurement of the entire volume during 6 hoursMeasurement of the average hydrocarbon concentrationMeasurement of the total volume of gasoline loaded during 6 hrsCalculation of the mass emitted/litre loaded averaged over 6 hrs

Continuous measuring system with complex and expensive devices

CIM : Control Inlet Monitoring CEM : Continuous Emissions Monitoring

In Europe : emissions measured as real emission concentrationSimple emissions monitor in the outlet line (infra-red detector)

Emission control


Energy consumption versus emissions

0

0,05

0,1

0,15

0,2

0,25

0,3

0510152025303540

Emission limit (g/m3)

Ener

gy c

onsu

mpt

ion

(kW

h/m

3 tr

eate

d) TA-Luft Emissions

EU Emissions

Israeli Emissions

N.B : Data based on LRVP Systems


Recovery chain

Refinery

Service-station

Terminal

Car filling

Losses : 0,1 kg/m3Emission reduction measures up to 99%

Losses : 1 kg/m3Emission reduction measures up to 90%

Losses : 1 kg/m3Emission reduction measures up to 99%

Losses : 1 kg/m3Emission reduction measures up to 99,99 %

Total efficiency of the recovery chain is never better than the weakest link









Stage 1 : Recovery of the vapour from the service-station ground tank to the truck and Recovery of the vapours from truck loading on the terminal.

Stage 2 : Recovery of the vapour from the car fuel tank to the ground tankNot ratified by some countries in Europe due to lack of

efficiency

EC Directive 94/63 Stage 1 and 2 for fuel distribution...


To VRU

At the Service Station

At the Terminal

Stage 2

Stage 1

Car

EC Directive 94/63 Stage 1 and 2 for fuel distribution


Service-station :Pressure / vacuum relief valve to be installed in the ground tank vent lineVapour return connection to be installed on the tank vent line

TruckTruck modified to bottom loadingOverfill protectionAll compartments connected to a central vapour collecting line equipped with 4" API coupler with check valve.

Implementation of Stage 1...


Terminal :

Modification from top loading to bottom loadingInstallation of a Vapour Recovery SystemVapour collecting line to the Vapour Recovery System Use of a dedicated gasoline tank for recovered productInstallation of floating roof in fixed roof type storage tanks or complete balancing of the vapour space to the VRUIntegration of a new process in the terminal and adaptation of operating and safety procedures

Implementation of Stage 1


Stage 1 example with fixed roof tanks

PT

Ventilator

Vapour Recovery Unit

Tanks

Detonation Arrestor

Pressure Vacuum Valve

P

Loading Operation

Vapours Emitted

Absorbents


Implementation of Stage 2

Cars :Installation of small canister in gasoline cars (91/441/CEE)Installation of large canister resisted by automobile industry

Service-stationInstallation of vapour balance system between car fuel tank and ground tank

For every litre of gasoline filled into the tank, one litre of vapouris returned to the ground tank

Efficiency not demonstrated Solutions not promoted by Oil Companies


During the loading of gasoline and diesel in trucks, the concentration of the vapours may vary between 0 to 50 % Vol. depending of :

• the nature of the products previously loaded.• the loading station (equipped or not acc. to Stage 1 and 2 of the EC Directive)

Theses hydrocarbons are generally composed of :

C1 0 - 0.2 % Vol.C2 0 - 0.45C3 1.5 - 3.8C4 37 - 50C5 22 - 43C6 8 - 12C7++ 1.7 - 5.4Benzene 0.26 - 2.6Toluene 0.36 - 1.8

C4 and C5 represent around 90% of the hydrocarbons at the inlet vapours

Typical vapour composition (Truck loading)









Important data for VRU sizing for truck and rail car loading:

• Peak flow rate= max. flow rate generated by the loading facility

(i.e max. number of loading points connected simultaneously x flow rate per point)→ Determination of the pressure drop of the VRU and the vapour collecting system→ Determination of the lines size, carbon bed diameterAll vapours have to pass through the VRU. Influence on price is small.

• Max. throughput per cycle = max. vapour amount generated in 15 minutes (for truck loading)

(i.e number of loading bays x volume loaded per cycle or vessel capacity)For continuous throughputs the cycle time is usually fixed at 12 minutes→ Determination of the activated carbon volume in the beds

• Max. throughput per 4 hour period= evaluation of the intensity of the activities at the terminal during the busiest period

→ Determination of the required vacuum capacity→ Determination of the re-absorber and absorbents circulation pumps

• Max. daily throughput = evaluation of the loading profile per day

→ Adjustment of the vacuum capacity

How to size a VRU


Typical compartment truck

Vapour Collector connected to each compartment

4” API Vapour Coupler

Compartment cover serves aspressure safety relief valve


Vapour Line

Pressure Vacuum Safety Valve

Detonation Arrestor

Level Switch

Drain valve

Vapour arm

Position Switch

VRU

Vapour Collecting System Truck loading Application








Absorbent Circulation System

VRU

P601

P501


Civil works


Civil works


Vapour

Recovery

Unit

CablingVapour pipe work

Nitrogen

Water

Gasoline

in out

Foundation drainage

Modem lineOpen/close Emergency VentEmergency vent valve positionPowerInput (start/stop truck loading)Gasoline pump start /stop/running signalSite ESD signalVRU runningVRU alarm

Air Air Compressor(instrument quality)

Control buildingmodem

Operations Room PC &interactive keyboard

Cabling

Electrical works : communication signals


Hazardous AreaSafe Area

Control Room

Cables

Electrical works


Electrical cables schematics

Electrical Room

VRU

J M

PLC

PC

I

Power feed cable

PC Monitoring

Power cables to MotorsInstrument cables

Customer signals


Power Cabinet

Control Cabinet

CONTROL ROOM

VRU SUPPLIER

Instrumentations

Modem

LOCAL REPRESENTATIVE

Modem

Modem

Operational connection schematic

E-Motors


Important parameters :Pressure drop of the vapour line- EU Directive : 55 mbar @ truck coupler- Typical ΔP of a 4" API vapour coupler : 3 mbar- Typical ΔP of a vapour arm + hose : 12 mbar- Typical ΔP of an anti-deto FA : 5 mbar- Typical ΔP of a VRU : 25 mbar

Max available ΔP of vapour line : 10 mbar

Pressure drop of the gasoline circulation lines- Supply pump : usually close to the tank or in the pump station- Return pump : usually on the VRU foundation

Accessibility for maintenance worksElectrical cable routing

VRU Location









Quality of the recovered productGasoline Application

Recovered product mostly C4 and C5.

Tendency to increase the absorbent ’s RVPTendency to increase the absorbent ’s temperature

Selection of a absorbent tank with a reasonable throughput


Hypotheses :

Vapour inlet concentration : Average outlet concentration :Average MW :

40 % Volume2g / Nm-3

65 (Gasoline vapours)

® Masse of hydrocarbons recovered 1159.5 g / m-3 of inlet vapour

The recovery rate :

§§

The effective recovery rate is 1.49 litre per m3

Vapour recovery rate 99. 9 %.Inlet vapour

Calculation :

0.4 x 65Mass of hydrocarbons at inlet per m-3 =

22.4 x 10 - 3= 1160,7 g / m-3

Masse of hydrocarbons in the outlet per m-3 inlet = 2 x (1 - 0.4) = 1.2 g / m-3

Typical Recovered Product


Tax refund in Europe

Recovered product not easily measured

Recovered product = only a small % of the return absorbent flowAccuracy of the metering devices not sufficient

Agreement between tax authorities and oil companies to implement a fixed rate equal to 1.4 to 1.5 litre per m3 of gasoline entering the terminal

1.4 litre/ m3 of the gasoline throughput exempted from taxes









VRU Safety

VRU are installed in environment containing combustible liquid and explosive gases

Risks of fire and explosion with toxic emissionsPreventive measures and risk analysis have to be performed :

HAZOP ATEX explosion protection document (EXDOC)SIL safety integrity level risk assessment


ATEX Philosophy

Four possible types of equipment :

AssembliesAssemblies with fully specified configuration of partsAssemblies with various configuration

InstallationsElectrical equipment

VRU is an assembly with fully specified configuration of parts (§ 3.7.1 of the ATEX guideline)


§ 3.7.1 Resume

VRU = assembly of two different pieces of equipment :

Equipment with CE marking (ATEX) :Manufacturer may presume conformity of these pieces

Equipment without CE marking :Manufacturer has to cover those parts with his own conformity assessment of the whole assembly

EC declaration of conformity for the whole unit (§ 3.7.1.1)Manufacturer assumes responsibility for compliance with the directiveManufacturer should provide a conformity assessment of the wholeassembly Manufacturer provides clear instructions for assembly / installation / operation / maintenance… in the operating manual.


Some of the VRU safety features

The whole system is explosion pressure proof to 9 bargAll valves with open / closed limit switchesGasoline pumps installed below liquid levelHigh and low level switches on the re-absorber columnTemperature monitoring in the activated carbon bedsOutlet temperature of the vacuum pump < 50°CDetonation arrestor in the inletTwo positive closing valves in each gasoline circulation lineetc...

VRU Safety features


VRU Explosion proof design


Detonation arrestor in inlet line and Valves with limit switches


Gasoline return pump


Level control and switches


Temperature sensors and indicatorsin carbon bed


Dry Vacuum Pump Temperature Monitoring


Two safety valves in each gasoline circulation line


Safety integrity level risk assessment of a dry screw VRS :4 elements to be assessed

Consequence of the risk (C)Minor InjurySerious Injury or permanent incapacityFatality or catastrophic incapacity

Frequency of exposure (F)Rare to more often (0 - 10%)Frequent to permanent (10 - 100%)

Safety Integrity Level...EN 61508‐5.2001


Possibility of avoidance of a hazardous event (P)Possible under certain conditionsAlmost impossible

Demand rate (W)High W3Low W2Very low W1

Result of SIL risk assessment is Category aNo special safety requirements

Safety Integrity LevelEN 61508‐5.2001


Minor Injury <1Serious Injury or permanent incapacityFatality or catastrophic incapacity

C1

Rare to more often ( 0 - 10% )Frequent to permanent ( 10 - 100% )

Possible under certain conditions P1 P1 P1 P1 P1 P1Almost impossible P2 P2 P2 P2 P2 P2

High W3 a 1 3 2 4 3 bLow W2 a 2 1 3 2 4

Very Low W1 1 a 2 1 3

Result of the Risk Reduction Estimation = a, no special safety requirements

F2F1

F2

Toxonomy

Possibility of avoidance of a hazardous event (P)

Demand Rate (W)

F1F2

F1

21a

321

432

>10C4

>1C3

<=11

C2

Toxonomy

Toxonomy

Frequency of Exposure (F)

Consequence of Risk (C)

Toxonomy

Result of SIL risk assessment

Documents

Presentation of Vapour Recovery Systems - M.P. Enggmpengg.com/carbovac_pdf_files/english_VRU_evolution.pdf · Presentation of Vapour Recovery Systems ... Flare gas recovery using