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Calcium Enhanced H 2 Production with CO 2 Captur e

Calcium Enhanced H 2 Production with CO 2 Captur e. Douglas P. Harrison Voorhies Professor Emeritus Cain Department of Chemical Engineering Louisiana State University Baton Rouge, LA USA harrison@lsu.edu ISCR 2008 Imperial College July 2008. Potential Applications.

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Calcium Enhanced H 2 Production with CO 2 Captur e

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  1. Calcium Enhanced H2 Production with CO2 Capture Douglas P. Harrison Voorhies Professor Emeritus Cain Department of Chemical Engineering Louisiana State University Baton Rouge, LA USA harrison@lsu.edu ISCR 2008 Imperial College July 2008

  2. Potential Applications Hydrogen Production: ≈95% to >99% Electricity Generation: from CH4 from coal Other Candidate Sorbents K-Hydrotalcite Mixed metal oxides of: Lithium Sodium

  3. Calcium Enhanced Hydrogen Production Reforming CH4(g) + H2O(g) ↔ CO(g) + 3H2(g) ∆Hro = 226 kJ/mol CH4 Shift CO(g) + H2O(g) ↔ CO2(g) + H2(g) ∆Hro = -38 kJ/mol CO Carbonation CO2(g) + CaO(s) ↔ CaCO3(s) ∆Hro = -178 kJ/mol CO2 Overall CH4(g) + 2H2O(g) + CaO(s) ↔ 4H2(g) + CaCO3(s) ∆Hro = -13 kJ/mol CH4

  4. Potential Advantages Simplification (or in some cases elimination) of the H2 purification section. Elimination of the shift reactor(s) and shift catalysts. Replacement of high temperature, high alloy steels in the reforming reactor with less expensive materials of construction. Reduction or possible elimination of carbon deposition in the reforming reactor. Reduced energy requirement.

  5. Thermodynamics 1.0 Reforming With CO2 Sorbent Without Ca(OH) 2 0.9 With Ca(OH)2 Mol fraction H2 (dry basis) 0.8 Reforming Without CO2 Sorbent P = 15 atm 0.7 Reactor Feed: 1 mol CH4 4 mol H2O 2 mol CaO 0.6 400 450 500 550 600 650 700 750 800 850 900 Temperature, oC

  6. Equilibrium H2 as Function of T and P

  7. Product Impurities at 15 bar 0.20 0.18 0.16 0.14 0.12 CH4 Component Mol Fraction (Dry Basis) 0.10 0.08 CO2 Reactor Feed 0.06 1 mol CH4 0.04 4 mol H2O CO 2 mol CaO 0.02 P = 15 bars 0.00 450 500 550 600 650 700 750 800 850 Temperature, oC

  8. Fixed-Bed Reactor Results at 15 bar (Balasubramanian et al., 1999) 100 % Conversion of CH4 to H2 25 Prebreakthrough (Dry Basis) 20 Reactor Packing Postbreakthrough 6.70 g CaO 15 7.00 g catalyst Feed P = 15 atm Mol Percent H2 CH4 6% 10 H2O 24% N2 70% Feed Rate 5 500 cm3(STP)/min 450 500 550 600 650 700 750 Temperature, oC

  9. Fixed-Bed Reactor Results at 1 bar (Yi and Harrison, 2005) 96.4% H2 50 ppmv CO

  10. Fluidized-Bed Results at 600oC, 1 atm, and S/C =3 (Johnsen et al., 2006)

  11. Sulfur Impurity in the Sorbent (Lopez et al., 2001) 25 20 , Dry Basis Feed 15 CH4 6 % H O 24 % 2 2 N 70 % % H 10 2 Q = 500 sccm. Reaction Conditions 5 Dolomite Calcined as Recieved o T = 650 C Dolomite Pretreated P = 15 atm 500 sccm 0 0 50 100 150 200 250 300 350 Time, min

  12. Regeneration for Multicycle Operation This is where the problems arise. Researchers are studying: • Naturally occurring sorbents • (limestone and dolomite). • Synthetic sorbents. • Sorbent reactivation.

  13. Regeneration Thermodynamics 100 CaO(s) + CO2(g)  CaCO3(s) PCO2 = 0.1 bar T > 750oC PCO2 = 1 bar T > 850oC PCO2 = 15 bar T > 1100oC 10 Carbonation Equilibrium CO2 Pressure, bar 1 Calcination 0.1 . 0 01 700 750 800 850 900 950 1000 1050 1100 1150 1200 Temperature, oC

  14. Performance Deterioration WithNaturally Occurring Sorbents(Bandi et al., 2002)

  15. 500-Cycle Results (Grasa and Abanades, 2006) Piasek Limestone: Calcination 850oC 1 atm 5 min Carbonation 650oC 1 atm 5 min PCO2 = 0.01 Mpa in air (both steps)

  16. 1000-Cycle Results (Sun et al., 2008) Carbonation 100% CO2 850oC Calcination 100%N2 850oC Asymptotic limit of 17% carbonation with 15 min carbonation time.

  17. Synthetic Sorbent: CaO (75%) and Ca12Al14O33 (25%):(Li et al., 2006) CaO-CA-2 1000oC calcination during preparation Carbonation: 650oC, 1 atm, 16% CO2/N2, 30 min Calcination 850oC, 1 atm 100% N2 5 min

  18. Synthetic Sorbent: 90% CaO/10% Al2O3(Stevens et al., 2007) Oxide powers produced using spray conversion powder technology by Cabot Superior MicroPowders. Carbonation: 600oC, 1 atm, 100% CO2, 1 hr Calcination: 800oC, 1 atm, 100% N2, 30 min 420-cycle experimental data was curve fit and extrapolated to 4380 cycles (1 year operation) to give a predicted capacity of 18.5% CO2.

  19. Steam Activation: Ca(OH)2 Formation (Manovic & Anthony, 2007) 20 calcination-carbonation cycles without activation Calcination 850oC, 1 atm, 100% N2, 30 min Carbonation 650oC, 1 atm, 20%CO2/N2 Activation Parr bomb, 200oC, 30 min, saturated steam

  20. Reactivation with Humid Air(Fennell et al., 2007) Three Limestones: Havelock, Purbeck, Cadomin Fluid Bed Carbonation: 750oC, 1 atm 14% CO2 in N2 Calcination: 750oC, 1 atm 100% N2 Hydration: Overnight at 20oC, 1 atm, in Air with PCO2≈0.023 bar

  21. SEHP Process With Steam Activation Regeneration Gas + CO2 Hydrogen Product Sorbent Purge Sorbent Makeup Spent Sorbent Reformer Regenerator Regeneration Energy Regenerated Sorbent Hydrator Natural Gas/Steam Regeneration Gas

  22. Regeneration Energy Options Regeneration GasEnergy InputFuel/OxidantComment CO2 Indirect H2/Air Max Temp/ Direct H2/O2 No H2O CO2/H2O Indirect H2/Air Direct CH4/O2 H2O Indirect H2/Air Min Temp/ Direct CH4/O2 Max H2O

  23. Process Analysis CH4 to H2 -- (Ochoa-Fernandes et al. 2006) CH4 to Electricity – (Reijers et al., 2006) Coal to Electricity – (MacKenzie et al., 2007) Coal to Electricity – (Li et al., 2008)

  24. CH4 to H2(Ochoa-Fernandes et al., 2006)

  25. CH4 to Electricity (Reijers et al., 2006) Design Basis: Natural gas combined cycle based on 380 MWe Siemens V94.3A gas turbine coupled with steam cycle Standard steam-methane reforming: η = 57.1% without CO2 capture η = 48% with 85% CO2 capture using MEA Sorption Enhanced H2 Production using CaO sorbent: Hydrogen Production: 600oC, 17 bar, H2O/CH4 = 3 Sorbent Regeneration: 1000oC, 17 bar, H2O/CO2 = 1.8 η = 52.6% with 85% CO2 capture

  26. Coal to Electricity (MacKenzie et al. 2007) • Order-of-Magnitude Economic Study • 360 MWe Pressurized Fluid Bed Combustor • 85% CO2 Capture • Capture Cost $23.70/metric ton CO2 (Canadian) • MEA Capture Cost $39 – $96/metric ton CO2 • (range from 11 literature sources)

  27. Sensitivity Analysis (MacKenzie et al., 2007) Reference Case Parameters Limestone Cost $25/tonne CaO Recycle Rate 92.5% Ca/C Ratio 4 CaO Deactivation Rate 15%/cycle

  28. Coal to Electricity(Li et al., 2008) * Results from Beer, 2007

  29. Conclusions H2 Production All looks good. Sorbent Regeneration No problem. Sorbent Durability Good progress. Process Simulation Favorable numbers.

  30. References Balasubramanian, B. et al., Hydrogen from Methane in a Single –Step Process, ChemEngSci, 1999, 54, 3543 Yi, K., Harrison D., Low Pressure Sorption Enhanced Hydrogen Production, IECRes., 2005, 44, 1665 Lopez, A., Harrison, D., Hydrogen Production Using Sorption Enhanced Reaction, IECRes, 2001, 40, 5102 Johnsen, K. et al., Sorption Enhanced Steam Reforming of Methane in a Fluidized Bed Reactor, ChemEngSci, 2006, 61, 1195 Bandi, A. et al., In Situ Gas Conditioning on Fuel Reforming for Hydrogen Generation, Proc. 5th Intl Symp Gas Cleaning, Pittsburgh, Sept. 2002 Grasa, G.S., Abanades, J.C. CO2 Capture Capacity of CaO in Long Series of Carbonation/Calcination Cycles, IECRes., 2006, 45, 8846 Sun, P. et al., Cyclic CO2 Capture of Limestone-Derived Sorbent During Prolonged Calcination/Carbonation Cycling, AIChE J., 2008, 54, 1668 Li, Z. et al., Effect of Preparation Temperature on Cyclic CO2 Capture and Multiple Carbonation-Calcination Cycles for a New Ca-Based CO2 Sorbent, IECRes., 2006, 45, 1911 Stevens, J.F. et al., Development of 50 kW Fuel Processor for Stationary Fuel Cell Applications, Final Report, DOE/GO/13102-1, 2007 Manovic, V., Anthony, E.J. Steam Reactivation of Spent CaO-Based Sorbent for Multiple CO2 Capture Cycles, EnvSciTech., 2007, 41, 1420

  31. References (cont) Fennell, P. S., Davidson, J. F., Dennis, J.S., and Hayhurts, A. N., Regeneration on Sintered Limestone for the Sequestration of CO2 from Combustion and Other Systems, JInstEnergy, 2007, 80, 116 Ochoa-Fernandez, E., Haugen, G., Zhao, T., Ronning, M., Aartun, I., Borresen, B., Rytter, E., Ronnekleiv, M., and Chen, D. Process Design Simulation of H2 Production by Sorption Enhanced Steam Methane Reforming: Evaluation of Potential CO2 Acceptors, GreenChem, 2007, 9, 654 Reijers, H., van Beurden, P., Elzinga, G., Kluiters, S., Dijkstra, J., van den Brink, R. A New Route for Hydrogen Production with Simultaneous CO2 Capture, World Hydrogen Energy Conference, Lyon, France, 2006 MacKenzie, A., Granatstein, D., Anthony, E., and Abanades, J., Economics of CO2 Capture Using the Calcium Cycle with a Pressurized Fluidized Bed Combustor, EnergyFuels, 21, 920, 2007. Li, Z., Cai, N., and Croiset, E., Process Analysis of CO2 Capture from Flue Gas Using Carbonation/Calcination Cycles, AIChE J, 2008, (online early publication) Beer, J., High Efficiency Electric Power Generation. The Environmental Role, ProgrEnergy & Comb Sci., 2007, 33, 107. More details: Harrison, D., Sorption Enhanced Hydrogen Production: A Review, IECRes, accepted for publication, May 2008

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