co2 removal from natural gas
TRANSCRIPT
Upstream Research
CO2 Removal from Natural Gas
B. T. (Rusty) Kelley27 April 2004
GCEP Energy WorkshopCarbon Capture & Separation
Stanford University
129-Apr-04 GCEP Energy Workshop -- Carbon Capture
Upstream ResearchTopics
• ExxonMobil Gas Treating Overview• Membrane Separation• Cyrogenic CO2 Separation• Gas Injection• Possible Research Directions
229-Apr-04 GCEP Energy Workshop -- Carbon Capture
Upstream ResearchGas Treating and InjectionGas Treating and Injection
Gas Treating
AGEUnit
ClausUnit
TGTUnit
Acid Gas Injection
Sour/Acid Gas InjectionSour/Acid Gas Injection• Alternative to sulfur disposal • Alternative to sulfur disposal • Captures other environmental benefits• Captures other environmental benefits• Can reduce life• Can reduce life--cycle costscycle costs• Potential for improved recovery• Potential for improved recovery
SufurSufur Recovery UnitRecovery Unit
ElementalElementalSulfurSulfur
COCO22,,ResidualResidualSulfur oxidesSulfur oxides
Gas TreatingGas Treating•• SolventsSolvents
––ChemicalChemical––PhysicalPhysical––HybridHybrid
•• MembranesMembranes•• CryogenicCryogenic•• Alkaline saltsAlkaline salts•• BatchBatch
Sour Gas Injection
Sweet GasSweet Gas
329-Apr-04 GCEP Energy Workshop -- Carbon Capture
Upstream ResearchGas Treating
0.1
1
10
100
0.0001 0.001 0.01 0.1 1 10 100
%H2S
%C
O2
Alkaline saltBatchHybridChemicalCyrogenicMembranePhysical
100 Mscfd
1000 Mscfd
429-Apr-04 GCEP Energy Workshop -- Carbon Capture
Upstream Research
CompetitiveSorption
Molecular Sieving
Large Pore Zeolite Small Pore Zeolite
CO2CH4
Pore SizeDetermines Selectivity
Surface Functionality Determines Selectivity
Separation Mechanisms
Inorganic Membrane MaterialsFor CO2/CH4 Separation
Silica (SiO2)
Both separation mechanisms in play Pores have hydroxyl groups that sorb water
0.5µmPorous
α−AluminaSupport
.05µm Silica Layer
Zeolites (MxSi1-xAlxO2)
Can operate via either mechanismMembrane fabrication challenging
• Very high CO2/CH4selctivity (>200)
• Good fouling resistance
1 µm
5 µm Thick DDR Zeolite Layer
Porous AluminaSupport
• Very High CO2/CH4selctivity (>100)
• Water stability is an issue
Porous γ−Alumina
Layer
529-Apr-04 GCEP Energy Workshop -- Carbon Capture
Upstream ResearchCryogenic CO2 Separation
100%Carbon Dioxide
100%Methane
Mixture Critical Locus
Feed
CO2CO2SolidificationSolidification
Pres
sure
Pres
sure
TemperatureTemperature
Upstream Research
PI
Integration with Injection
•• HH22S/SulfurS/Sulfur-- Eliminates Claus/TGT units, sulfur blocksEliminates Claus/TGT units, sulfur blocks
++ Saturated sulfur marketsSaturated sulfur markets+ + Slow development of alternative usesSlow development of alternative uses
•• COCO22-- Some producers may have COSome producers may have CO22 incentivesincentives-- Enhanced oil recovery possibleEnhanced oil recovery possible
CFZ is easily CFZ is easily integrated with integrated with acid gas injectionacid gas injection Dry
Gas
CHCH44, N, N22
H2S, CO2
CFZ
729-Apr-04 GCEP Energy Workshop -- Carbon Capture
Upstream Research
100 Mscfd, 40% acid gas & 950 psig plant inlet100 Mscfd, 40% acid gas & 950 psig plant inlet
Sweetening Process ScreeningSweetening Process Screening
ChemicalChemical PhysicalPhysical11 CFZCFZ11
Capital InvestmentCapital Investment 1.41.4 1.31.3 1.01.0Annual Operating CostAnnual Operating Cost 1.41.4 1.191.19 1.01.0Plant HorsepowerPlant Horsepower 1.51.5 1.411.41 1.01.0Gas salesGas sales 0.910.91 0.930.93 1.01.0
1 1 ---- from study by independent consultantfrom study by independent consultant
829-Apr-04 GCEP Energy Workshop -- Carbon Capture
Upstream ResearchAcid & Sour Gas Injection Existing, Planned, or Evaluated
58 tons CO2/Mscf
65% H2S
1% H2S
17% H2S
20% H2S
0.5% H2S
17% H2S
28% H2S
4% H2S
NG
N2N2, NG
1
10
100
1,000
10,000
0 2,000 4,000 6,000 8,000 10,000 12,000
Pressure, psig
Rat
e, M
scfd
Typical sour / acid gas projects (most in USA & Canada)
500 MW power plant flue gas
500 MW power plant CO2
Blue -- Acid gas
Red -- Sour gas
Green -- N2, NG
929-Apr-04 GCEP Energy Workshop -- Carbon Capture
Upstream ResearchPossible Research Directions for CO2 CaptureGCEP goal: Identify and conduct fundamental, pre-commercial
research to overcome barriers that will allowtechnology options to become commercially viable
Challenge: Make electric power production with low specific CO2 emissions cost competitive assuming no non-market incentives
• Fundamental not incremental• Economically competitive not just improved economically• Leveraged and integrated with best efforts to date that have
identified and evaluated CO2 capture technologies• Applicable to multiple future scenarios