Acid Gas Removal Options for Minimizing Methane Emissions Lessons Learned from Natural Gas STAR...

Acid Gas Removal Options for Acid Gas Removal Options for Minimizing Methane EmissionsMinimizing Methane Emissions

Lessons Learned from Natural Gas STARLessons Learned from Natural Gas STAR

Processors Technology Transfer WorkshopProcessors Technology Transfer Workshop

Gas Processors Association,Gas Processors Association,Devon Energy, Enogex, Devon Energy, Enogex,

Dynegy Midstream Services andDynegy Midstream Services andEPA’s Natural Gas STAR ProgramEPA’s Natural Gas STAR Program

April 22, 2005April 22, 2005

Reducing Emissions, Increasing Efficiency, Maximizing Profits

Acid Gas Removal: AgendaAcid Gas Removal: Agenda

Methane LossesMethane Losses

Methane RecoveryMethane Recovery

Is Recovery Profitable?Is Recovery Profitable?

Industry ExperienceIndustry Experience

Discussion QuestionsDiscussion Questions


Methane Losses from Acid Gas RemovalMethane Losses from Acid Gas Removal

There are 291 acid gas removal (AGR) units in There are 291 acid gas removal (AGR) units in gas processing plantsgas processing plants11

Emit 646 MMcf annuallyEmit 646 MMcf annually11

6 Mcf/day emitted by average AGR unit6 Mcf/day emitted by average AGR unit11

Most AGR units use diethanol amine (DEA) Most AGR units use diethanol amine (DEA) process or Selexolprocess or SelexolTMTM process process

Several new processes have recently been Several new processes have recently been introduced to the gas processing industryintroduced to the gas processing industry

11Inventory of U.S. Greenhouse Gas Emissions and Sinks 1990 - 2002 Inventory of U.S. Greenhouse Gas Emissions and Sinks 1990 - 2002


What is the Problem?What is the Problem?

1/3 of U.S. gas reserves contain CO1/3 of U.S. gas reserves contain CO22 and/or N and/or N2211

Wellhead natural gas may contain acid gasesWellhead natural gas may contain acid gases HH22S, COS, CO2,2, are corrosive to gathering/boosting and are corrosive to gathering/boosting and

transmission lines, compressors, pneumatic instruments transmission lines, compressors, pneumatic instruments and distribution equipmentand distribution equipment

Acid gas removal processes have traditionally used Acid gas removal processes have traditionally used DEA to absorb acid gasDEA to absorb acid gas

DEA regeneration strips acid gas (and absorbed DEA regeneration strips acid gas (and absorbed methane)methane) COCO22 (with methane) is typically vented to the atmosphere (with methane) is typically vented to the atmosphere

HH22S is typically flared or sent to sulfur recoveryS is typically flared or sent to sulfur recovery

11www.engelhard.com/documents/GPApaper2002.pdfwww.engelhard.com/documents/GPApaper2002.pdf


Typical Amine ProcessTypical Amine Process

Filter

Exchanger

Booster Pump

Flash Tank

Sour Gas

Sweet Gas

Contractor (Absorber)

Rich Amine

Lean AmineStripper (DEA) Condenser

H2S to sulfur plant or flare

Reflux Pump

Reboiler

Heating Medium

CO2 to atmosphere


Methane Recovery - New Acid Gas Methane Recovery - New Acid Gas Removal TechnologiesRemoval Technologies

GTI & Uhde MorphysorbGTI & Uhde Morphysorb® ® ProcessProcess

Engelhard Molecular GateEngelhard Molecular Gate®® Process Process

Kvaerner Membrane ProcessKvaerner Membrane Process

Primary driver is process economics, not Primary driver is process economics, not methane emissions savingsmethane emissions savings

Reduce methane venting by 50 to 100%Reduce methane venting by 50 to 100%


MorphysorbMorphysorb®® Process Process

Absorber

Feed GasFlash 1

Flash 2

Clean Gas

Flash 3

Flash 4

Acid Gas

Compression

Compression

Pump


MorphysorbMorphysorb®® Process Process

MorphysorbMorphysorb®® absorbs acid gas but also absorbs acid gas but also absorbs some methaneabsorbs some methane Methane absorbed is 66% to 75% lower than Methane absorbed is 66% to 75% lower than

competing solventscompeting solvents11

Flash vessels 1 & 2 recycled to absorber inlet Flash vessels 1 & 2 recycled to absorber inlet to minimize methane lossesto minimize methane losses

Flash vessels 3 & 4 at lower pressure to Flash vessels 3 & 4 at lower pressure to remove acid gas and regenerate Morphysorbremove acid gas and regenerate Morphysorb®®

11Oil and Gas Journal, July 12, 2004, p57Oil and Gas Journal, July 12, 2004, p57



MorphysorbMorphysorb®® can process streams with high (>10%) can process streams with high (>10%) acid gas compositionacid gas composition

30% to 40% Morphysorb30% to 40% Morphysorb®® operating cost advantage operating cost advantage over DEA or Selexolover DEA or SelexolTM 2TM 2

66% to 75% less methane absorbed than DEA or Selexol66% to 75% less methane absorbed than DEA or SelexolTMTM

About 33% less THC absorbedAbout 33% less THC absorbed22

Lower solvent circulation volumesLower solvent circulation volumes

At least 25% capital cost advantage from smaller At least 25% capital cost advantage from smaller contactor and recyclescontactor and recycles22

Flash recycles 1 & 2 recover ~80% of methane that is Flash recycles 1 & 2 recover ~80% of methane that is absorbedabsorbed11

11Oil and Gas Journal, July 12, 2004, p57, Fig. 7Oil and Gas Journal, July 12, 2004, p57, Fig. 7

22GTIGTI


Industry Experience - Duke EnergyIndustry Experience - Duke Energy

Kwoen plant does not produce pipeline-spec gasKwoen plant does not produce pipeline-spec gas Separates acid gas and reinjects it in reservoirSeparates acid gas and reinjects it in reservoir Frees gathering and processing capacity further Frees gathering and processing capacity further

downstreamdownstream

MorpysorbMorpysorb®® used in process unit designed for used in process unit designed for other solventother solvent

MorphysorbMorphysorb®® chosen for acid gas selectivity over chosen for acid gas selectivity over methanemethane Less recycle volumes; reduced compressor Less recycle volumes; reduced compressor

horsepowerhorsepower


Methane Recovery - Molecular GateMethane Recovery - Molecular Gate®® COCO2 2 RemovalRemoval

Adsorbs acid gas contaminants in fixed bedAdsorbs acid gas contaminants in fixed bed Molecular sieve application selectively adsorbs acid Molecular sieve application selectively adsorbs acid

gas molecules of smaller diameter than methanegas molecules of smaller diameter than methane Bed regenerated by depressuringBed regenerated by depressuring

5% to 10% of feed methane lost in “tail gas” depressuring5% to 10% of feed methane lost in “tail gas” depressuring Route tail gas to fuel Route tail gas to fuel

CH4

CO2

C3+ adsorbed on binder


Molecular GateMolecular Gate®® Applicability Applicability

Lean gasLean gas Gas wellsGas wells Coal bed methaneCoal bed methane

Associated gasAssociated gas Tidelands Oil Production Co.Tidelands Oil Production Co.

• 1 MMcf/d1 MMcf/d• 18% to 40% CO18% to 40% CO22

• Water saturatedWater saturated Design options for CDesign options for C44+ in tail gas stream+ in tail gas stream

• Heavy hydrocarbon recovery before Molecular GateHeavy hydrocarbon recovery before Molecular Gate®®

• Recover heavies from tail gas in absorber bedRecover heavies from tail gas in absorber bed• Use as fuel for process equipmentUse as fuel for process equipment

www.engelhard.com


Molecular GateMolecular Gate®® CO CO22 RemovalRemoval

10 psi pressure drop

Product95% of C1

90% of C2

50% of C3

5 psia

Tail Gas5% of C1

10% of C2

50% of C3

C4+

CO2

H2S

H2O

Enriched C1

30 psia

High Pressure Feed C1

C2

C3

C4+ CO2

H2S

H2O

Pressure Swing

Adsorption

VacuumCompressor

C4+ Recovery

Dehydration


Industry Experience - Tidelands Industry Experience - Tidelands Molecular GateMolecular Gate®® Unit Unit

www.engelhard.com/documents/CO2%20Removal-1.pdf

First commercial unit started on First commercial unit started on May 2002May 2002

Process up to 10 MMcf/dProcess up to 10 MMcf/d Separate recycle compressor is Separate recycle compressor is

requiredrequired No glycol system is requiredNo glycol system is required Heavy HC removed with COHeavy HC removed with CO22

Tail gas used for fuel is a key Tail gas used for fuel is a key optimization: No process ventingoptimization: No process venting

18% to 40% CO18% to 40% CO2 2 removed to removed to pipeline specifications (2%)pipeline specifications (2%)



Molecular GateMolecular Gate®® costs are 20% less than amine costs are 20% less than amine processprocess 9 to 35 9 to 35 ¢ / ¢ / Mcf product depending on scaleMcf product depending on scale

Fixed-bed tail gas vent can be used as Fixed-bed tail gas vent can be used as supplemental fuelsupplemental fuel Eliminates venting from acid gas removalEliminates venting from acid gas removal

Other BenefitsOther Benefits Allows wells with high acid gas content to produce Allows wells with high acid gas content to produce

(alternative is shut-in)(alternative is shut-in) Can dehydrate and remove acid gas to pipeline Can dehydrate and remove acid gas to pipeline

specs in one stepspecs in one step Less operator attentionLess operator attention


Kvaerner Membrane ProcessKvaerner Membrane Process

Adapted from “Trimming Residue CO2 with Membrane

Technology,” 2005

MEMBRANEUNIT

Aerosol Separators

Bypass for Fuel

High CO2 Permeate

Feed Gas

Bypass for Blending

Pipeline Spec

Fuel Gas Spec

(trace lube, glycol, etc. removal)

Membrane separation of COMembrane separation of CO22 from feed gas from feed gas Cellulose acetate spiral wound membraneCellulose acetate spiral wound membrane

High COHigh CO22 permeate (effluent or waste stream) exiting the permeate (effluent or waste stream) exiting the membrane is vented or blended into fuel gasmembrane is vented or blended into fuel gas

Low COLow CO22 product exiting the membrane exceeds pipeline product exiting the membrane exceeds pipeline spec and is blended with feed gasspec and is blended with feed gas


Kvaerner Membrane TechnologyKvaerner Membrane Technology

COCO22 (and some methane) diffuse (and some methane) diffuse axially through the membraneaxially through the membrane

High-COHigh-CO22 permeate exits from center permeate exits from center of tube; enriched product exits from of tube; enriched product exits from outer annular sectionouter annular section

One application for fuel gas permeateOne application for fuel gas permeate Methane/COMethane/CO22 waste stream is added waste stream is added

with fuel gas in a ratio to keep with fuel gas in a ratio to keep compressor emissions in compliancecompressor emissions in compliance

Design RequirementsDesign Requirements Upstream separators remove Upstream separators remove

contaminants which may foul contaminants which may foul membranemembrane

Line heater may be necessaryLine heater may be necessaryDuke Energy Field Services


Industry Experience – Duke EnergyIndustry Experience – Duke Energy

Kvaerner process installed at Mewborn processing Kvaerner process installed at Mewborn processing plant in Colorado, 2003plant in Colorado, 2003

Problem: Sales gas COProblem: Sales gas CO22 content increasing above the content increasing above the 3% pipeline spec3% pipeline spec

Evaluated optionsEvaluated options Blend with better-than-spec gasBlend with better-than-spec gas

• Not enough availableNot enough available Use cryogenic NGL recovery to Use cryogenic NGL recovery to

reject COreject CO22

• Infrastructure/capital costs too Infrastructure/capital costs too highhigh

Final choice: membrane or Final choice: membrane or amine unitamine unitDuke Energy Field Services


Industry ExperienceIndustry Experience

Flow Into Flow Into MembraneMembrane

Membrane Residue Membrane Residue (Product)(Product)

Membrane Membrane PermeatePermeate

22.3 MMcf/d22.3 MMcf/d 2121 1.31.3

70 to 110 70 to 110 ooFF 70 to 11070 to 110 70 to 11070 to 110

800 to 865 psia800 to 865 psia 835835 5555

3% CO3% CO222%2% 16%16%

84% C184% C1 89%89% 77%77%

13% C2+13% C2+ 9%9% 7%7%

~0% H~0% H22OO ~0%~0% ~0%~0%

~0% H~0% H22SS ~0%~0% ~0%~0%

Membrane chosen for other advantages; zero emissions is Membrane chosen for other advantages; zero emissions is added benefitadded benefit 65% less capital cost than amine unit65% less capital cost than amine unit <10% less operating cost<10% less operating cost <10% less operator man hours<10% less operator man hours

Typical Process conditionsTypical Process conditions

1/3 footprint of amine unit1/3 footprint of amine unit Less process upsetsLess process upsets Less noiseLess noise Less additional infrastructure Less additional infrastructure

constructionconstruction



CostsCosts Conventional DEA AGR would cost $4.5 to $5 million Conventional DEA AGR would cost $4.5 to $5 million

capital, $0.5 million O&Mcapital, $0.5 million O&M Kvaerner Membrane process cost $1.5 to $1.7 million Kvaerner Membrane process cost $1.5 to $1.7 million

capital, $0.02 to $0.05 million O&Mcapital, $0.02 to $0.05 million O&M Optimization of permeate streamOptimization of permeate stream

Permeate mixed with fuel gas, $5/Mcf fuel creditPermeate mixed with fuel gas, $5/Mcf fuel credit Only installed enough membranes to take feed from >3% to Only installed enough membranes to take feed from >3% to

>2% CO>2% CO22, and have an economic supplemental fuel supply , and have an economic supplemental fuel supply for compressorsfor compressors

In operation for 1 yearIn operation for 1 year Offshore Middle East using NATCO membrane process Offshore Middle East using NATCO membrane process

on gas with 90% COon gas with 90% CO22, achieving pipeline spec quality, achieving pipeline spec quality


Comparison of AGR AlternativesComparison of AGR Alternatives

Amine (or Amine (or SelexolSelexolTMTM) ) ProcessProcess

MorphysorbMorphysorb® Process® Process

Molecular Molecular GateGate®® CO CO22

Kvaerner Kvaerner MembraneMembrane

Absorbent orAbsorbent or

AdsorbentAdsorbent

Water & Water & AmineAmine

(Selexol(SelexolTMTM))

Morpholine Morpholine DerivativesDerivatives

Titanium Titanium SilicateSilicate

Cellulose Cellulose AcetateAcetate

Methane Methane SavingsSavings

100%100% 66 to 75%66 to 75% 0%0% 0% or higher0% or higher

RegenerationRegenerationReduce Reduce

Pressure & Pressure & HeatHeat

Reduce Reduce PressurePressure

Reduce Reduce Pressure to Pressure to

VacuumVacuum

Replace Replace Membrane Membrane

~5 years~5 years

Primary Primary Operating CostsOperating Costs

Amine Amine (Selexol(SelexolTMTM) & ) &

SteamSteam

ElectricityElectricity ElectricityElectricity NilNil

Capital CostCapital Cost

Operating CostOperating Cost

100%100%

100%100%

75%75%

60% to 70%60% to 70%

<100%<100%

80%80%

35%35%

<10%<10%


Discussion QuestionsDiscussion Questions

Have you studied any of these new Have you studied any of these new technologies?technologies?

How can our presentation be improved to How can our presentation be improved to help you find new opportunities to reduce help you find new opportunities to reduce methane emissions from AGR units?methane emissions from AGR units?

What are the barriers (technological, What are the barriers (technological, economic, lack of information, regulatory, economic, lack of information, regulatory, focus, manpower, etc.) that are preventing focus, manpower, etc.) that are preventing you fromyou from implementing either of these implementing either of these technologies?technologies?

Acid Gas Removal Options for Minimizing Methane Emissions Lessons Learned from Natural Gas STAR...

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