Slagging & Fouling SNCR (NH 4 ) 2 SO 4. CO 2 purity. H 2 SO 4 corrosion. HEX acid dew point ph & porosity Cooling - H 2 SO 4. Enhanced SO 3 coating

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1 Sulphur Impacts in Coal Fired Oxy-fuel Combustion with CCS (Impacts and Control Options) Terry Wall a, Rohan Stanger a *, Joerg Maier b a Chemical Engineering, University of Newcastle, 238, Australia; b University of Stuttgart, Germany

2 Outline General sulphur impacts Pilot Work Sulphur Thermodynamics Control and Mitigation

3 The Oxy-fuel Process ASU Combustion Slagging & Fouling Higher SCR H2S SO & COS 3 formation SNCR (NH 4 ) 2 SO 4 O 2 CO2 Compression CO 2 purity Coal Handling ESP Transport Sequestration Site (Pipeline, Truck, Ship) Recycle Enhanced SO 3 coating H 2 SO 4 corrosion Deep Geological Storage HEX acid dew point ph & porosity Cooling - H 2 SO 4

4 Pilot Work IHI Test facility Callide Oxy-fuel Project 3 coals Air & Oxy-fuel Each test ~ 3 hours Some work previously reported

5 IHI Pilot Plant PAF Oxy-fuel combustion flowchart Electrical heater Furnace Ash Deposits SO 2 / SO 3 Sampling positions Pulverized coal Radiative Section Gas cooler Air heater Gas cooler Bag filter IDF Stack Convective section Bottom Ash Equal velocity aspiration sample Fly Ash Air Electrical heater Steam gas heater Water spray tower FDF/GRF O2

6 Pilot SO 2 Results 2 15 x3 higher 5 4 SO O2, ppm (dry) 1 SO2, mg/mj Fuel-S, % % less Fuel-S, % Oxy-fuel concentration higher but produces LESS total SO 2 Higher concentration acts as driver for secondary products

7 Pilot SO3 Results 2 15 Measured Oxy Fired o C Oxy Fired SO3, ppm (dry) 1 5 Acid Dew Point, Air Fired Measured Air Fired Fuel-S, % Fuel-S, %

8 Pilot Ash Results Air Oxy Fly Ash Air Fired Oxy Fired Coal C SO3, % S as S as SO3, % (ad) Coal C Fuel-S, % Bottom Ash Fly Ash Deposit Radiative Deposit Convective No SO3 in Bottom Ash and Radiative Deposits for other coals

9 Mass Balance & Thermodynamics

10 Theoretical Mass Balance 4 Measured Air SO2, m (dry) pp 3 2 Measured Oxy Difference due to the formation of secondary sulphur products Fuel-S, %

11 Theoretical Mass Balance 4 Oxy - hot recycle ppm Theoret tical SO2, Oxy - recycle after NOx,SOx, H2O removed Air Fired Effect of Recycle Fuel-S, % Effect of Lower Flow Rate

12 In-flame Sulphur Products (Coal A Thermodynamics at 15 C) SO 3 H2S io 1 tio 1 Oxy/Air otal Molar Rati T SO 3 COS Oxy/Air otal Molar Rat T SO 2 COS 2 SO 2 H2S Equivalence Ratio ONCE THROUGH (O 2 /CO 2 vs O 2 /N 2 ) Equivalence Ratio WITH RECYCLE (~69% recycle, 28% O2 IN, 5% O2 OUT)

13 SO 2 Conversion to SO 3 S SO2 SO3 Con nversion, % IVD Pilot-.5.5 MW MW t t (Maier et et al ) al) IHI Pilot- 1.2 MW t (this study) OXY - AIR - SO 3 Fuel-S Air Oxy %, db ppm ppm Coal A Coal B Coal C Temperature, C 1 C used to estimate SO3 conversion for acid dew point (Okkes, Verhoff & Banchero methods)

14 Mitigation Options Air Separation Unit O 2 Soot Blowing N 2 Low S Coal CO2 compression Coal Handling ESP Sulphur Scrubber Transport (pipeline, truck, etc) Sequestration Site Limestone Sulphur removal in compression circuit Condenser/ Cooler Recycled Flue Gas Sulphur Scrubber Deep Geological Storage

15 Control Strategies SO2 limited - low sulphur coals SO2 removed - FGD (85-98% capture) Limestone addition (<5% capture) High calcium coals (5-1% capture) Cooling/Caustic wash (Air Liquide) In compression (Air Products) In purification Soot-blowers Flue Gas above acid dew point Corrosion resistant materials

16 Conclusion Pilot Sulphur Higher SO2 in Oxy-fuel Higher SO3 & acid dew point Fly Ash & Bottom Ash unaffected Oxy-fuel Deposits higher in S

17 Conclusion- Sulphur Impacts Sulphur Impacts throughout oxy-fuel CCS Oxy-fuel SO 2 - higher conc, lower output SO 2 Concentration ti driver for S products Furnace Products different with recycle SO 3 conversion ~thermodynamics 1 C

18 Thank you for your attention

19

20 Sulphur Impacts Furnace Convective Pass SCR ESP Heat Exchange Compression CO 2 Purity Transport Storage corrosion, slagging corrosion, fouling fouling, catalytic formation- SO 3 higher performance acid dew point H 2 SO 4 SO 2 corrosion, H 2 SO 4 Corrosion, injection (ph zone)

21 In-flame Sulphur Products (Thermodynamics at 15 C) O XY/AIR Concen ntration ratio 7 6 COS SO SO2 1 H2S Equivalence Ratio OXY/AIR Concen ntration Ratio 7 SO3 H2S 6 5 COS 4 SO Equivalence Ratio ONCE THROUGH WITH RECYCLE (O 2 /CO 2 vs O 2 /N 2 ) (~69% recycle, 28% O2 IN, 5% O2 OUT)

22 SO 2 in Compression High Low H2O H2O Scenario 5ppm 5ppm For Aquifer EOR Storage - 1ppm - 3% O2, O2, 1ppm SO2, SO2, 5ppm 5ppm H2O, H2O, CO2 CO2 balance balance (Dynamis Project recommendations for Pre-combustion capture)

23 IVD - Stuttgart SO2 H2S SO2+H2S O (SO 2 +H 2 S)max SO 2, H 2 S [p ppm] 4 2 AIR-BLOWN COMBUSTION_LAUSITZ O2 [vol% %] SO 2, H 2 S [p ppm] 4 2 OF27_3 COMBUSTION_LAUSITZ O 2 [vol% %] (SO 2 +H 2 S)max Distance from Burner [m] Distance from Burner [m]

24 Sulphur Products & Effects Acid dew point Corrosion in compression 1. Convective Fouling Cooling Flue Gas In-flame reduction products H 2 SO 4 SO 2 Equilibri ium SO Temperature, o C

25 Limestone Addition C erature, C Tempe SO2, ppm * Assumes max Ca/S = 2

26 Limestone Addition * Assumes max Ca/S = 2