Integrated CO 2 capture study for a coal fired station. Philippe Delage (ALSTOM) & Paul Broutin (IFP)

Transcription

1 Integrated CO 2 capture study for a coal fired station Philippe Delage (ALSTOM) & Paul Broutin (IFP) 1

2 Introduction Bases of the study Integration study Conclusions 2

3 Objectives of the eco2 Study Study sponsored by ADEME (French Environment and Energy Management State Agency) Identify major features for integration between CO 2 capture process and coal-fired power plant 2 integrated CO 2 capture processes studied on a CFB SC boiler scrubbing with Mono Ethanol Amine solution, oxyfiring CFB SC boiler 3

4 Introduction Bases of the study Integration study Conclusions 4

5 Bases of the Study CFB supercritical boiler 270 bar / 600 C life steam, 60 bar / 600 C reheat steam Feedstock: International bituminous coal Seaside location 15 C) CO 2 capture: 90 % CO 2 available at 110 barabs at battery limits 5

6 Reference Plant Performance (without capture) Supercritical CFB Plant performance Without capture Fuel input, MW (LHV) 1400 Gross power output, MW 685 Ancillary power consumption and losses, MW 55 Net Power Output, MW 630 Thermal Efficiency, % (LHV)

7 Simulation methodology ALPRO software from ALSTOM Power was used to simulate the power plant Hysys from Aspen Tech was used by IFP to simulate the CO 2 capture plant, the Air Separation Unit and CO 2 compression Iterative approach using the results from both softwares 7

8 Introduction Bases of the study Integration study Conclusions 8

9 Integration with steam cycle Integration has impact on steam cycle With postcombustion capture, the steam turbine is adapted to accomodate large quantity of extracted steam. With oxyfiring the heat is recovered without modification of the steam turbine. ALSTOM steam turbine in ESBJERG power plant, Denmark (Net power output: 350 MW, District heating: 459 MJ/s) 9

10 CFB with post-combustion capture Quench Tower CO 2 Capture 10

11 Major integration aspects / Post-combustion capture Integration of the steam cycle Heat recovery from absorption/desorption loop Heat recovery from compression Flue gas sulphur & particulates removal Flue gas cooling Position of booster fan Electrical distribution 11

12 CO 2 capture system process flow diagram 12

13 Capture process heat recovery for post-combustion capture Optimisation of the heat recovery from the capture process is the main target to improve efficiency Constraint: the condensate flow is reduced due to the steam extraction for amine regeneration Three main heat sources Heat sources Inlet Temperature ( C) Outlet Temperature ( C) Available heat (MJ/sec) Heat recovered (MJ/sec) Condenser top of the stripper Lean solution sub-cooling CO 2 compressors intercooling

14 Optimisation of the absorption/desorption loop The influence of the variation of the lean amine has been investigated. A lean loading of around 0.24 mol/mol appears to be the optimum value (using the Hysys software) Steam Consum ption M J/kg CO lean loading mol/mol 14

15 Optimisation of the absorption/desorption loop (continued) By a better heat integration with the absorption/desorption loop, the power necessary for the capture can be reduced by 5%. An additional 3% reduction can be achieved by cooling the flue gas to 30 C instead of 40 C at the inlet of the absorber. 15

16 Oxy-fired CFB 16

17 Major integration aspects / oxyfiring Integration of the steam cycle Heat recovery from ASU Heat recovery from compression Flue gas sulphur & particulates removal CO 2 Recirculation rate Electrical distribution 17

18 Capture process heat recovery for oxyfiring Optimisation of the heat recovery from the compressors intercooling is main target to improve efficiency Two main heat sources Heat sources Inlet Temperature ( C) Outlet Temperature ( C) Available heat (MJ/sec) Heat recovered (MJ/sec) ASU compressors intercooling CO 2 compressors intercooling 3 stages

19 Comparison of the performances Reference Plant (without capture) CO 2 Capture by MEA scrubbing Oxyfiring Heat Input (LHV) (MW) Gross Power output, (MW) Electrical consuption (MW) Net Power (MW) Net efficiency (%) (33.8 without integration and capture loop optimisation) 36.4 (35.8 without integration)

20 Introduction Bases of the study Integration study Conclusions 20

21 Conclusions Solutions for CO 2 capture are available, Economical comparison show the solutions to be close to each other, Integration is then a key factor of selection, Different type of expertises shall be combined to optimise the processes, Effective simulation has been made possible with in-house ALSTOM software ALPRO and IFP's knowledge in using simulation tools such as Hysys software. 21

22 Thank You! 22