CO2 Capture from IGCC Gas Streams Using the AC-ABC Process

2016 NETL CO2 Capture Technology Meeting August 08, 2016 Pittsburgh, PA

Anoop Nagaranoop.nagar@sri.com

Project Overview• Project Participants:

– SRI International.– Bechtel Hydrocarbon Treatment Solutions, Inc.– EIG, Inc.– National Carbon Capture Center– U.S. DOE (National Energy Technology Laboratory)

• Funding:– U.S. Department of Energy: $5,828,047– Cost Share (SRI and BHTS): $1,662,648– Total: $7,490,695

• Performance Dates:– October 2009 through September 2016

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Project Objectives

• Overall objective:– To develop an innovative, low-cost CO2 capture technology based on

absorption on a high-capacity and low-cost aqueous ammoniated solution with high pressure absorber and stripper.

• Specific objectives and project status:– Test the concept on a bench scale batch reactor (completed)– Determine the preliminary optimum operating conditions (completed)– Design and build a small pilot-scale reactor capable of continuous

integrated operation (completed)– Perform tests to evaluate the process in a coal gasifier environment

(completed)– Perform a technical and economic evaluation on the technology

(Updates are in progress)

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Process Fundamentals• Uses well-known reaction between carbon dioxide and

aqueous ammonia :

• Reactions are reversible – Absorption reactions at lower temperature – Desorption reactions at higher temperature

• High pressure operation enhances absorption of CO2

• A similar set of reactions occur between H2S and ammoniated solution

• H2S from the regenerated gas is converted to elemental sulfur at high pressures

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NH4OH+CO2 NH4HCO3

(NH4) 2CO3+CO2 + H2O 2NH4HCO3

NH4 (NH2CO2)+CO2+2H2O 2NH4HCO3

Process Block Flow Diagram

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Process Highlights• Concentrated ammoniated solution is used to capture

both CO2 and H2S from syngas at high pressure.• Absorber operation at 40o-60o C temperature; No

refrigeration is needed.• CO2 is released at high pressure (30 bar) at <200°C:

– The size of CO2 stripper, the number of stages of CO2 compression, and the electric power for compression of CO2 to the pipeline pressure are reduced.

• High net CO2 loading, up to 20 wt. %.• The stripper off-gas stream, containing primarily CO2 and

H2S, is treated using a high pressure Claus process, invented by Bechtel, to form elemental sulfur.– CO2 is retained at high pressures.

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Process Advantages• Low cost and readily available reagent (aqueous ammonia).• Reagent is chemically stable under the operating conditions.

– Ammonia does not decompose under the operating conditions.

• High efficiency for CO2 capture– Reduces water-gas shift requirements - Reduced steam consumption.

• No loss of CO2 during sulfur recovery– High pressure conversion; No tail gas treatment

• Low heat consumption for CO2 stripping (<600 Btu/lb CO2)– <1.5 GJ/Tonne CO2

• Extremely low solubility of H2, CO and CH4 in absorber solution: Minimizes loss of fuel species.

• Absorber and regenerator can operate at similar pressure. – No need to pump solution across pressure boundaries. Low energy

consumption for pumping.

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Bench scale data - CO2 Capture Efficiency vs Solution Composition

8

0

10

20

30

40

50

60

70

80

90

100

0.40 0.45 0.50 0.55 0.60 0.65 0.70 0.75 0.80

Cap

ture

Effi

cien

cy (%

)

R' (Molar Ratio, CO2/NH3)

Run 17 (4 M, 50 C)

Run 16 (4 M, 33 C)

Run 18 (4 M, 45 C)

Run 19 (4 M, 60 C)

Run 20 (4 M, 43 C)

Run 21 (8 M, 55 C)

Inlet CO2 Partial Pressure 450 kPa

8 M, 55 C4 M, 60 C

4 M, 43 C

Reactor Volume = 0.0045 m3

Reactor Pressue = 265 psia

CO2 Capture Efficiency Exceeds 90%

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Pilot data - CO2 Capture Efficiency > 99%

0.00

2.00

4.00

6.00

8.00

10.00

12.00

14.00

16.00

18.00

CO2

mol

e %

Hours

CO2 in raw Syngas

CO2 in Clean Syngas

Syngas ON

Water Ingress in CO2 meterPilot Run # 3Absorber @ 350 psigAmmonia 5 Molal

Pilot data – absorption pressure and temperature

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0.00

50.00

100.00

150.00

200.00

250.00

300.00

350.00

400.00

Pres

sure

, psi

g /

Tem

pera

ture

, F

Hours

Absorber pressure

Absorber bottom temperature

Pilot Run # 3Absorber @ 350 psigAmmonia 5 MolalCO2 / NH3 ratio 0.35 – 0.45

Bench scale data - Rapid Rate of Reaction Approaching Equilibrium

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0

10

20

30

40

50

0.1 0.2 0.3 0.4 0.5 0.6 0.7

CO

2Pa

rtial

Pre

ssur

e at

the

Exit

(psi

a)

R', Molar Ratio CO2/NH3

Run 17 (4 M, 50 C)

Run 16 (4 M, 33 C)

Run 13 (4 M, 45 C)

Run 11 (4 M, 45 C)

Run 18 (4 M, 45 C)

Run 19 (4 M, 60 C)

Run 20 (4 M, 43 C)

Run 21 (8 M, 55 C)

Equilibrium Line (10 M, 55 C)

Absorber Operating Pressure = 1800 kPa (265 psia)4 M and 8M Ammonia, 0.88 acfm CO2 flow rate (25 %v/v)

Pilot data - CO2 in clean syngas

12

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

0.80

0.90

1.00

CO2

mol

e %

Hours

CO2 in clean syngas < 1000 ppmPossible to get even lower CO2 at higher pressure

Pilot Run # 3Absorber @ 350 psigAmmonia 5 MolalCO2 / NH3 ratio 0.35 – 0.45

Pilot data - H2S capture efficiency > 99%

13

0

20

40

60

80

100

120

140

160

180

200

0.0

500.0

1000.0

1500.0

2000.0

2500.0

H2S

ppm

in C

lean

Syn

gas

H2S

ppm

in S

ynga

s

Hours

H2S in raw Syngas

H2S in Clean Syngas - below detection limit of 2 ppm

NOTE: Data from GC measurement by NCCCPilot Run # 3Absorber @ 350 psigAmmonia 5 Molal

Bench scale data - Measured CO2 Attainable Pressure Function of Temperature

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0

100

200

300

400

500

600

700

800

900

0 50 100 150 200 250

Tota

l Pre

ssur

e (p

si)

Temperature (οC)

Run 1

Run 2

Run 3

Run 4

Run 5

Vapor Pressure of Water

AC-ABC

Pilot data – Absorption and Regeneration at high pressure

15

0

50

100

150

200

250

300

350

400

450

Pres

sure

, ps

ig

Time (hh:mm)

Absorber pressure

Regenerator pressure

Pilot Run # 10Absorber @ 350 psigRegenerator @ 350 - 375 psigAmmonia 7-9 MolalCO2 / NH3 ratio 0.35 leanCO2 / NH3 ratio 0.60 rich

Regenerated gas stream

Pilot data – Regeneration at moderate temperature

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0

50

100

150

200

250

300

350

400

Tem

pera

ture

(F)

Time (hh:mm)

Reboiler temperature

Pilot Run # 10Absorber @ 350 psigRegenerator @ 350 - 375 psigAmmonia 7-9 MolalCO2 / NH3 ratio 0.35 leanCO2 / NH3 ratio 0.60 rich

Pilot data - Steam input for regeneration

17

0

500

1000

1500

2000

2500

Ener

gy u

se, B

TU/l

bCO

2 /

H2S

Time (hh:mm)

Reboiler duty

Actual steam used, BTU/lb CO2+H2S

Corrected steam used, BTU/lb CO2+H2S

Pilot Run # 10Absorber @ 350 psigRegenerator @ 350 - 375 psig

Pilot data – Effective CO2 loading

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0

2

4

6

8

10

12

14

16

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

0.80

CO2

load

ing,

wt%

CO2/

NH

3m

ole

ratio

Time (hours)

CO2/NH3 ratio in lean solution

CO2 loading

Pilot Run # 10Absorber @ 350 psigRegenerator @ 350 - 375 psigAmmonia 7-9 Molal

Pilot data - Ammonia emission from absorber

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0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

Amm

onia

in A

bsor

ber G

as o

utle

t (pp

m)

Time (hh:mm)

Added Ammonia to lean solution

Lost syngas

7 Molal Ammonia in solution

8 Molal Ammonia in solution

11 Molal Ammonia in solution

Pilot Run # 10Absorber @ 350 psig

Pilot data – Regenerated gas stream

20

95

96

97

98

99

100

0

0.5

1

1.5

2

2.5

CO2

mol

e %

H2S

, mol

e %

2nd Test CampaignFrom grab sample GC analysisOn dry basis

Pilot data – Regenerated gas stream contd.

21

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45

0.5

Mol

e %

, dry

bas

is

H2 (%)Ar (%)N2 (%)CH4 (%)CO (%)

2nd Test CampaignFrom grab sample GC analysisOn dry basis

AC-ABC Process Schematic

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Sour water

Clean Syngas

Syngas Feed Steam

Shift 1

Boiler Feed water

To BPSC

Steam

Shift 2

CO2/H2SStripper

dP=10-20psi

PFD for the NCCC Test

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AC-ABC / BPSC pilot at NCCC

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1st Test Campaign - August/Sept 2015 – 300 hr. operation2nd Test Campaign April/May 2016 – 400 hr. operation

Syngas Compressor and inlet gas manifold

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Analytical equipment cabinet, pressurized- CO2 measurement- Ammonia

measurement

AC-ABC columns and skids

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Process columns- SS 316, 8” dia., 40’ tallProcess skids- 5’ x 10’ – 2 skids

Electrical, control and data acquisition

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Pump speed controllers

Process controllers

Data acquisition system

Bechtel Pressure Swing Claus (BPSC) Process

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BPSC Process Skid -Columns and sulfur condenser

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Catalytic reactors, 4” dia., 10’ tall

Condensers

2 Skids – 5’ x 10’ and 10’ x 14’

Elemental sulfur

AC-ABC and BPSC Process Changes to IGCC Reference Case

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Plant Performance Summary

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Plant Performance Units IGCC with SRI AC-ABC and BPSC

Reference Case IGCC with CO2 capture B5B#

Gas Turbine Power MWe 464.0 464.0

Syngas Expander Power MWe 6.3 6.5

Steam Turbine Power MWe 243.8 263.5

Auxiliary Load MWe 162.5 190.8

Net Plant Power MWe 551.6 543.3

Net Plant Efficiency (HHV) - 33.1% 32.6%

Net Plant Heat Rate (HHV) kJ/kWh Btu/kWh

10,1669,636

11,034 10,458

# Cost and Performance Baseline for Fossil Energy Plants, Vol 1b, July 31, 2015, Table ES-2

Economic Analysis

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Economic Analysis (base 2011$) IGCC with SRI AC-ABC and BPSC

Reference Case IGCC with CO2 capture

B5B#

Total Plant Cost, before Owner's Costs, million $1,648 $1,840

Total Plant Cost, before Owner's Costs $2,988/kW $3,387/kW

Initial Chemical Fill Cost, million $4.90 $16.50

Annual Fixed O&M Cost, million $69.40 $69.40

Annual Variable O&M Cost, million $41.20 $46.60

Total Annual O&M Cost, million $110.60 $116.00

FY COE* without TS&M** $124.46 $135.56

FY COE with TS&M $133.66 $144.76

COE (% increase from base case IGCC, no CO2 capture) 30.3 % 41.2 %

*FY COE = First Year Cost of Electricity**TS&M = Transport, Storage, and Monitoring# Cost and Performance Baseline for Fossil Energy Plants, Vol 1b, July 31, 2015, Table ES-4

Anticipated Benefits

• We estimate a 8.3 MW improvement in Net Plant Power and a 0.5 % point increase in Net Plant Efficiency (HHV basis) than a reference plant (GE gasifier with Selexol AGR and conventional Claus).

• Capital cost is ~10 % less than the reference IGCC plant with CO2 capture.

• The COE is 7.5 % lower for the SRI AC-ABC/BPSC plant relative to the reference IGCC case with CO2 capture.

• The process configuration is economically viable per this analysis.

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Acknowledgement• SRI International

– Anoop Nagar, Marc Hornbostel, Jin-Ping Lim, Elisabeth McLaughlin, Bill Olson

• EIG: – Eli Gal

• Bechtel Hydrocarbon Treatment Solutions: – Lee Schmoe, Martin Taylor

• National Carbon Capture Center: – Scott Machovec, Patrick Crossley

• DOE-NETL– Steve Mascaro

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DISCLAIMERThis presentation was prepared as an account of work sponsored by an agency of the

United States Government. Neither the United States Government nor any agency

thereof, nor any of their employees, makes any warranty, express or implied, or assumes

any legal liability or responsibility for the accuracy, completeness, or usefulness of any

information, apparatus, product, or process disclosed, or represents that its use would

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necessarily constitute or imply endorsement, recommendation, or favoring by the United

States Government or any agency thereof. The views and opinions of authors expressed

herein do not necessarily state or reflect those of the United States Government or any

agency thereof.

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Thank You

Contact:Anoop NagarSRI International650.859.3942anoop.nagar@sri.com