Integration of carbon capture unit with power generation: technology advances in oxy-combustion plants

Transcription

1 Integration of carbon capture unit with power generation: technology advances in oxy-combustion plants 3 rd Oxyfuel Combustion Conference, OCC3 9 th -13 th September 2013, Ponferrada, Spain Luca Mancuso, Foster Wheeler Noemi Ferrari, Foster Wheeler Vince White, Air Products John Davison, IEAGHG Foster Wheeler All rights reserved.

2 Introduction IEAGHG undertook studies on performance and costs of coal-fired power and hydrogen plants with CO 2 capture, based on the three leading options: post combustion capture Background oxy-combustion for pulverised coal plants pre-combustion capture in gasification pants Following significant technological advances and substantial increase of plant costs, IEAGHG decided to undertake a completely new study to provide an up-to-date techno-economic assessment Study is almost complete and it will be issued in coming months 1

3 Introduction Study objectives Study aims to provide baseline for subsequent studies on other capture processes and capture in industries other than power and hydrogen generation. It covers the following plant types: Supercritical pulverised coal (SC-PC) power plant without CO 2 capture (reference plant) Oxy-combustion SC-PC with cryogenic purification SC-PC with post combustion capture based on a high efficiency solvent IGCC plant with pre-combustion capture using solvent scrubbing Gasification for combined production of hydrogen (via PSA) and power (either via combined cycle or boiler-based plant), with pre-combustion capture using solvent scrubbing 2

4 Introduction List in alphabetical order: Air Products Alstom Cansolv Chiyoda Corporation Foster Wheeler General Electric Energy IHI Johnson Matthey Mitsubishi Heavy Industries (gasification and gas turbines) Shell UOP Acknowledgement Fruitful cooperation with various technology suppliers and licensors, which provided an invaluable support for the success of the study 3

5 Technology advances in oxy-combustion plants Study cases: design bases Agenda Key design features Performance Economics Conclusions 4

6 Oxy-combustion SC-PC power plant Main design basis 5

7 Oxy-combustion SC-PC power plant Main design features Flue Gas Desulphurisation Type: dry, wet,... Installation on total flue gas flow, primary recycle, secondary recycle Air Products CPU Sour compression for NOx and SOx abatement Distillation column required to meet CO 2 purity specification: max 100 ppmv O 2 with CO 2 Thermal integration Additional membrane unit 6

8 Oxy-combustion SC-PC power plant Main design features Thermal integration CPU and ASU compressors inter / after-cooler Heat Recovery from flue gases 7

9 CO 2 purification and compression Air Products process 8

10 Air Products Sour compression scheme NOx and SOx removal 9

11 1 st contacting column: SOx removal Air Products Sour compression scheme NOx and SOx removal 98-99% SOx removed as H 2 SO 4 Pressure level: 15 bar Main reactions NO + ½ O 2 低 2 NO 2 + SO 2 + H 2 低 䠠 2SO 4 2 NO 2 + H 2 Mercury removal as nitrate 10

12 2 nd contacting column: NOx removal Air Products Sour compression scheme NOx and SOx removal 90% NOx removed as HNO 3 Pressure level: 30 bar Main reactions 2 NO 2 + H 2 11

13 Flue gas desulphurisation Why? NOT required to reduce SOx emission to atmosphere (or in the CO 2 product) Installed to reduce SOx concentration in the furnace and flue gas ducts to avoid excessive corrosion %wt S FGD not required 0.5% FGD installation Coal sulphur content 2% When and Where? Primary recycle (high removal efficiency) Secondary recycle or total flue gas flow (low removal efficiency) FGD installation SOx < ppm Secondary recycle (high removal efficiency) Total flue gas flow (low removal efficiency) 12

14 Dry FGD on primary recycle Flue gas desulphurisation Which technology? Circulating fluid bed scrubber with lime sorbent Small sized FGD (lower capital), high removal efficiency (95%) Lower flexibility to coal sulphur content Max heat recovery from flue gases Wet FGD on secondary recycle Wet FGD with limestone sorbent Saleable gypsum product Bigger sized FGD (higher capital), low removal efficiency (60%) Higher flexibility to coal sulphur content 13

15 Increasing plant efficiency Thermal integration between process unit and steam cycle Condensate pre-heating ASU compressor after-coolers Flue gas heat recovery Sour compression (first stage: 1-15 bar after cooler) BFW pre-heating Flue gas heat recovery Sour compression (first stage: 1-15 bar after cooler) Significant impact on steam cycle efficiency: High value steam saving! 14

16 Increasing plant efficiency Heat Recovery in the sour compression section Inert gas pre-heating No HP steam consumption No inerts gas heating in the furnace: simple layout! 15

17 Oxy-combustion plant: 90% CO 2 capture 16

18 Oxy-combustion plant: 90% CO 2 capture 17

19 Oxy-combustion plant: 90% CO 2 capture (1) Reference plant: SC-PC boiler w/o CO 2 capture 18

20 Near zero carbon emission PRISM membrane: 98% CO 2 capture 19

21 Increasing CO 2 capture... near-zero emission power plant Delta performance and costs 20

22 Conclusions Technology advances in oxy-combustion plants A plant net electrical efficiency of 35.7%, with a CO 2 removal efficiency of 90%, is technically feasible Oxy-combustion technology is particularly suited to meet near zero carbon emission CO 2 capture provides best economics for CO 2 emission cost higher than 61 /t Considerations also apply to the oxy-combustion CFB boiler technology 21

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