NOx CONTROL FOR IGCC FACILITIES STEAM vs. NITROGEN

Transcription

1 NOx CONTROL FOR IGCC FACILITIES STEAM vs. NITROGEN GASIFICATION TECHNOLOGIES CONFERENCE SAN FRANCISCO, CALIFORNIA OCT , 2002 Phil Amick, Global Energy Inc. Ron Herbanek, Global Energy Inc. Robert M. Jones, General Electric Co. 1

2 IGCC is different than NGCC Natural Gas Combined Cycle Plants Feedstock with Near-Zero Sulfur Content Steam or Water Injection, or Dry Low NOx Combustors, in GT Selective Catalytic Reduction (SCR) in GT Exhaust NOx Levels < 6 ppm and as low as 2 ppm Integrated Gasification Combined Cycle Plants Steam Injection or Nitrogen Dilution at GT Combustors SCR Not Economically Viable without Deep Sulfur Removal Wabash & Polk Permitted at 25 ppm, New Plants at 15 ppm 2

3 Wabash Basis NOx Permit 25 ppm Midwest 61F Average Ambient, ~75-80F Average Summer IGCC without Steam Export, Power Sales Only Low Pressure ASU, No ASU-GT Integration Oxygen Compressor on ASU Excess Steam in Thermal Cycle with Existing STG 3

4 Wabash River LP ASU and Steam Injection Steam Turbine Combustion Turbine Gasification Plant Oxygen Plant 4

5 Wabash ASU 5

6 Study Basis NOx Permit 15 ppm Gulf Coast 61F Average Ambient, 90F Average Summer Standard E-Gas Integrated Design 3 x 7FA Combustion Turbine Reheat Steam Turbine Syngas Cooler HRSG Integration ASU with Pumped Liquid Oxygen Petcoke Fueled IGCC without Steam Export, Power Sales Only 6

7 E-GAS IGCC STUDY MODEL Nitrogen Dilution Only Steam Injection Only B Nitrogen Syngas DA ASU Extraction Air Air GTG (2) G H-P L-P HRSG (2) Saturated HP Steam BFP Hot BFW 95% Oxygen A Air Warm BFW MP Steam Feedstock Process Water GASIFICATION Cold Condensate STG (1) HP IP LP LP G B Waste Water Slag A Warm Condensate CT Demin. Makeup Sulfur CONDENSER 7

8 IGCC Choice: Steam or Nitrogen Primary Impacts of Steam versus Nitrogen Decision Air Separation Unit Design Auxiliary Power Consumption Gross Generation, especially at Summer Ambient Temperatures Capital Cost Other Impacts Heat Rate Water Consumption 8

9 Combustion Turbines Diluent Steam Nitrogen Ambient Temperature 61F 90F 61F 90F Diluent Flow, MLB/hr Air Extraction, Mlb/hr Syngas Used, MMBtu/hr LHV GT Gross Power, MW Delta at Ambient 0 (43) 9

10 Air Plant for Steam Injection AIR MAC AIR PLANT N2 O2 Steam (~400 psig) extracted from the STG is fed to the GT combustors AIR BAC STEAM SYNGAS Air Separation Unit operates at lower pressure (~65 psig MAC outlet) G GTG 10

11 Air Plant for Nitrogen Dilution AIR AIR MAC BAC GTG AIR PLANT G O2 N2 N2C SYNGAS Nitrogen from the ASU is compressed (N2C) and fed to GT combustors Air extracted from the GT feeds to Air Separation parallel to MAC High Pressure ASU with 170 psig MAC outlet is required to minimize N2C HP 11

12 ASU Auxiliary Power Diluent Steam Nitrogen Ambient Temperature 61F 90F 61F 90F ASU Power Consumption, MW MAC BAC N2C Other TOTAL Delta at Ambient (44.1) (59.6) 12

13 Steam Turbine Steam Turbine 1500 psig/1050f Throttle, nominal 400 psig reheat Diluent Steam Nitrogen Ambient Temperature 61F 90F 61F 90F Throttle Flow, MLB/hr STIG Extraction, Mlb/hr ST Gross Power, MW Delta at Ambient (53.3) (71.5) 13

14 Diluent Steam Nitrogen Ambient Temperature 61F 90F 61F 90F Gross Generation, MW Gas Turbines Steam Turbine Aux Power, MW ASU Gasification Combined Cycle Net Power, MW Delta at Ambient (7.9) (51.5) 14 IGCC Performance

15 Impact on Summertime Performance N2 Dilution - Incremental Capacity 70,000 Incremental Capacity, kw 60,000 50,000 40,000 30,000 20,000 10, Ambient Temp, F Annualized Incremental Power Output is 22 MW. 15

16 Capital Cost Impacts Diluent Steam Nitrogen Air Separation Base $ 11.1 MM Steam Turbine Base $ 8.0 MM Demineralizer Base $ (2.4 MM) Delta $ 16.7 MM 16

17 Conclusions Nitrogen Dilution: Higher Capital Cost than Steam Injection (2-3% of CapEx) Provides Additional Net Power Output, More Pronounced at High Ambient, Approaching 6% of IGCC Rating at 90F. On An Annualized Output Basis for Warmer Areas, the Incremental Capacity Costs About $800/kW 17

18 References General Electric, Combustion Turbine Performance Air Liquide, ASU Budget & Performance Cost Estimates for these cases are derived from the Gasification Plant Performance and Cost Optimization Study performed for DOE by Nexant, Bechtel, and Global Energy. The Task 1 Report is now on the NETL website at systems/docs/40342r01.pdf 18