Chemical production of hydrogen with insitu

Transcription

1 Chemical production of hydrogen with insitu separation Ian S. Metcalfe Professor of Chemical Engineering Newcastle University 21 May 2013

2 Introduction Uses of hydrogen How is hydrogen made Process intensification Gas solid reactions, simultaneous reaction and separation and breaking equilibrium Membranes Chemical looping

3 Uses of hydrogen Ammonia production Fuel upgrading (HDS, HDN and hydrocracking) Hydrogenation of fats in the food industry Hydrogen as a fuel is not a significant use If you produce and sell hydrogen it will not be used as a fuel

4 Uses Conventional Method (steam methane reforming) 2 Hot air balloons CH 4 + H 2 O Steam reforming o C, Ni catalyst 3 H 2 + CO Agriculture Light Fuel Hydrogenation Water gas shift CO + H 2 O H 2 + CO o C, Fe catalyst 200 o C, Cu catalyst H 2 + CO 2 PSA H 2 Fuel cell CO 2 Energy intensive, very expensive, PSA separation. Cost increases with required purity. Introduction Steam-Iron Process Thermodynamics Materials Results Future Work

5 Hydrogen production

6 Energy balance 5 (CH 4 + 2H 2 O = CO 2 + 4H 2) ΔH R 0 = ~+850 kj/mol CH 4 + 2O 2 = CO 2 + 2H 2 O ΔH R 0 = ~-890 kj/mol 6CH 4 + 2O 2 + 8H 2 O = 6CO H 2 Autothermal Not far off CH O 2 + H 2 O = CO 2 + 3H 2

7 Catalytic reaction engineering challenges Improved selectivity of reforming (avoid carbon deposition and loss of catalyst activity). Modifying Ni catalysts. Partial oxidation instead of reforming remove need for heat transfer (capital cost of plant depends on heat transfer load and reformers are heat transfer limited NOT kinetically limited). Involves air separation. New processes involving reaction and separation dynamic or membrane processes. Processes to break equilibrium for WGS (also allows higher temperatures to be used). LT WGS catalysts are not suitable for distributed processes due to slow kinetics.

8 Produce hydrogen from dissociation of water Use of a reduced solid surface for the dissociation of water and production of hydrogen: H 2 O

9 Produce hydrogen from dissociation of water Use of a reduced solid surface for the dissociation of water and production of hydrogen: CO CO 2 O

10 Produce hydrogen from dissociation of water Use of a reduced solid surface for the dissociation of water and production of hydrogen: H 2 O CO CO 2

11 Water-gas shift reaction thermodynamics CO + H 2 O = CO 2 + H 2 ΔH R 0 (25C) = -41 kj/mol ΔG R 0 (810C) = 0 kj/mol ln K K G RT P P P CO2 CO P 0 H 2 H 2O

12 WGS thermodynamics batch operation Batch operation CO + H 2 O = CO 2 + H 2 P P H 2O H 2 H 2 O CO H 2, H 2 O CO 2, CO Virtual oxygen chemical potential Equilibrium P P CO CO2 Time

13 Membrane-based WGS Co-current operation CO + H 2 O = CO 2 + H 2 P P H 2O H 2 H 2 O CO H 2, H 2 O CO 2, CO Virtual oxygen chemical potential Equilibrium P P CO CO2 Length

14 Membrane-based WGS Counter-current operation CO + H 2 O = CO 2 + H 2 Virtual oxygen chemical potential No equilibrium limitation Smaller driving forces for permeation P P H 2O H 2 H 2, H 2 O CO H 2 O CO 2, CO P P CO CO2 Length

15 Chemical looping WGS CO + H 2 O = CO 2 + H 2 CO CO 2 H 2 H 2 O

16 Materials ceramic of choice : perovskite (mineral CaTiO 3 ) general formula ABO 3 (A +2 B +4 O 3 or A +3 B +3 O 3 ) A Ca 2+ / large cation e.g., La, Sr lattice O 2- anion lattice O 2- anion vacancy B Ti 4+ / small cation e.g., Co, Fe

17 Hydrogen production from SMR CH 4 membrane CO 2H 2 2h + H 2 O H 2 O 2-

18 Microtubular membranes LSCF (La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3-δ ) Supplied by Kang Li of Imperial College

19 Mole fraction / % Membrane-based steam reforming LSCF 900 C T = 900 C H 2 O (7.2%) 20ml(STP)min -1 H 2 O O + H 2 H CH 4 (5%) 20ml(STP)min -1 H 2 O 2- CO,H CH 4 CH4 off R.V. Franca, A. Thursfield and I. S. Metcalfe, La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3 microtubular membranes for hydrogen production from water splitting J. Membrane Sci. 389 (2012) Time / hours

20 Steam-Iron Process (using natural gas reducing feed) 3 CO Process invented in 1907 Requires no separation step CO 2 High Purity H 2 Fe 3 O 4 STEAM- IRON CYCLE Fe Cyclic Process H 2 H 2 O Introduction Steam-Iron Process Thermodynamics Materials Results Future Work

21 Baur-Glaessner phase diagram M. F. Bleeker, S. R. A. Kersten and H. J. Veringa, Catalysis Today, 2007, 127,

22 Chemical looping WGS CO 2 2h + 2h + O 2- H 2 O H 2 O O 2-

23 Chemical looping WGS CO CO 2 2h + O 2-2h + O 2-

24 La 0.7 Sr 0.3 FeO 3-δ (LSF731) oxygen deficiency (δ) in relation to ph2o/ph2 850oC A. Murugan, A. Thursfield and I. S. Metcalfe, A chemical looping process for hydrogen production using ironcontaining perovskites Energy Environ. Sci. 4(11) (2011)

25 Fe60 behaviour Fixed bed microreactor 1st (solid line) and 150th (dashed line) isothermal chemical looping WGS cycles recorded at 850oC for 50 mg of (c) Fe60, reduction in carbon monoxide (d) Fe60, reoxidation in water. Arrows indicate oxidation state changes of iron in Fe60 according to thermodynamic studies.

26 LSF731 behaviour Fixed bed microreactor 1st (solid line) and 150th (dashed line) isothermal chemical looping WGS cycles recorded at 850oC for 50 mg of (a) LSF731, reduction in carbon monoxide (b) LSF731, reoxidation in water. Arrows indicate oxidation state changes of iron in Fe60 according to thermodynamic studies.

27 Cycling of LSF731 and iron oxide A. Murugan, A. Thursfield and I. S. Metcalfe, A chemical looping process for hydrogen production using iron-containing perovskites Energy Environ. Sci. 4(11) (2011) Molar production (with error bars) during isothermal cycling at 850oC for 50 mg of (a) LSF731, reduction in carbon monoxide (b) LSF731, reoxidation in water, (c) and (d) are for iron oxide.

28 Conclusion Uses of hydrogen How is hydrogen made Process intensification Gas solid reactions, simultaneous reaction and separation and breaking equilibrium Membranes Chemical looping

29 Acknowledgements Dr Alan Thursfield, Dr Arul Murugan, Dr Danai Poulidi, Dr Cristina Dueso, Dr Anne Huber, Dr Rafael Vilar Franca, Ms Claire Thompson, Dr Walairat Suksamai, Hang Qi EPSRC for funding under the SUPERGEN programme and PLATFORM grant, ERC Advanced Grant Professor Kang Li, Imperial College

30 References Tan, X., Li, K., Thursfield, A., Metcalfe. I. S., Oxyfuel combustion using a catalytic ceramic membrane reactor, Catalysis Today 131 (2008) R.V. Franca, A. Thursfield and I. S. Metcalfe, La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3 microtubular membranes for hydrogen production from water splitting J. Membrane Sci. 389 (2012) A. M. Kierzkowska, C. D. Bohn, S. A. Scott, J. P. Cleeton, J. S. Dennis and C. R. Muller, Ind. Eng. Chem. Res., 2010, 49, A. Murugan, A. Thursfield and I. S. Metcalfe, A chemical looping process for hydrogen production using iron-containing perovskites Energy Environ. Sci. 4(11) (2011) Alan Thursfield, Arul Murugan, Rafael Franca and Ian S. Metcalfe, 'Chemical looping and oxygen permeable ceramic membranes for hydrogen production A review', Energy Environ. Sci. 5(6) (2012)

31 END