Ammonia Decomposition Coupled with Methane Combustion in Catalytic Microreactors for Hydrogen Production
Chemical and Biomolecular Engineering
Volume 2, Issue 1, March 2017, Pages: 19-26
Received: Jan. 3, 2017;
Accepted: Jan. 14, 2017;
Published: Feb. 6, 2017
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Junjie Chen, Department of Energy and Power Engineering, School of Mechanical and Power Engineering, Henan Polytechnic University, Jiaozuo, China
Longfei Yan, Department of Energy and Power Engineering, School of Mechanical and Power Engineering, Henan Polytechnic University, Jiaozuo, China
The ammonia decomposition over ruthenium thermally coupled with the catalytic combustion of methane-air mixtures over platinum in catalytic microreactors for hydrogen production was studied numerically, using a two-dimensional computational fluid dynamics model that included detailed chemistry and transport. The effect of flow configuration on the operation characteristics was studied in catalytic microreactors consisting of alternating combustion and decomposition channels separated by a thermally conducting wall. Different performance measures were evaluated to assess the operability of the reactor. It was shown that the high temperatures generated through catalytic combustion result in high conversion in short contact times and thus to compact reactors. Complete conversion of ammonia can be obtained at the micro-scale in both flow configurations. A proper balance of the flow rates of the decomposition and combustion streams is crucial in achieving this. For a given flow rate of combustible mixture, material stability determines the lower power limit, caused by high temperatures generated at low decomposition stream flow rates. In contrast, the maximum power generated is determined by extinction at large decomposition stream flow rates. The two flow configurations were contrasted based on multiple performance criteria, such as reactor temperature, conversion, power exchanged, and hydrogen yield by constructing operating regime. They were found to be practically equivalent for highly conductive materials. Using properly balanced flow rates, the co-current flow configuration expands the operating regime to low and moderate thermal conductivity materials as compared to the counter-current flow configuration that exhibits a slightly superior performance but in a rather narrow operating regime of highly conductive materials and high ammonia flow rates.
Ammonia Decomposition Coupled with Methane Combustion in Catalytic Microreactors for Hydrogen Production, Chemical and Biomolecular Engineering.
Vol. 2, No. 1,
2017, pp. 19-26.
J. D. Holladay and Y. Wang. A review of recent advances in numerical simulations of microscale fuel processor for hydrogen production. Journal of Power Sources, Volume 282, 2015, Pages 602-621.
V. R. Regatte and N. S. Kaisare. Hydrogen generation in spatially coupled cross-flow microreactors. Chemical Engineering Journal, Volumes 215-216, 2013, Pages 876-885.
R. C. Ramaswamy, P. A. Ramachandran, and M. P. Duduković. Recuperative coupling of exothermic and endothermic reactions. Chemical Engineering Science, Volume 61, Issue 2, 2006, Pages 459-472.
G. Kolios, J. Frauhammer, and G. Eigenberger. Autothermal fixed-bed reactor concepts. Chemical Engineering Science, Volume 55, Issue 24, 2000, Pages 5945-5967.
G. D. Stefanidis and D. G. Vlachos. High vs. low temperature reforming for hydrogen production via microtechnology. Chemical Engineering Science, Volume 64, Issue 23, 2009, Pages 4856-4865.
S. R. Deshmukh and D. G. Vlachos. Effect of flow configuration on the operation of coupled combustor/reformer microdevices for hydrogen production. Chemical Engineering Science, Volume 60, Issue 21, 2005, Pages 5718-5728.
Fluent 6.3 user’s guide. Lebanon, New Hampshire: Fluent Inc., 2006.
R. J. Kee, F. M. Rupley, E. Meeks, and J. A. Miller. CHEMKIN-III: a Fortran chemical kinetics package for the analysis of gasphase chemical and plasma kinetics, Report No. SAND96-8216, Sandia National Laboratories, 1996.
M. E. Coltrin, R. J. Kee, F. M. Rupley, and E. Meeks. SURFACE CHEMKIN-III: a Fortran package for analyzing heterogeneous chemical kinetics at a solid-surface-gas-phase interface, Report No. SAND96-8217, Sandia National Laboratories, 1996.
O. Deutschmann, L. I. Maier, U. Riedel, A. H. Stroemman, and R. W. Dibble. Hydrogen assisted catalytic combustion of methane on platinum. Catalysis Today, Volume 59, Issues 1-2, 2000, Pages 141-150.
S. R. Deshmukh, A. B. Mhadeshwar, and D. G. Vlachos. Microreactor modeling for hydrogen production from ammonia decomposition on ruthenium. Industrial & Engineering Chemistry Research, Volume 43, Issue 12, 2004, Pages 2986-2999.
O. Deutschmann, S. Tischer, C. Correa, D. Chatterjee, S. Kleditzsch, V. M. Janardhanan, N. Mladenov, H. D. Minh, H. Karadeniz, and M. Hettel, DETCHEM Software package, 2.5 Edition, www.detchem.com, Karlsruhe, 2014.
R. J. Kee, G. Dixon-lewis, J. Warnatz, M. E. Coltrin, J. A. Miller, and H. K. Moffat. A Fortran computer code package for the evaluation of gas-phase, multicomponent transport properties, Report No. SAND86-8246B, Sandia National Laboratories, 1998.
D. G. Norton and D. G. Vlachos. Combustion characteristics and flame stability at the microscale: a CFD study of premixed methane/air mixtures. Chemical Engineering Science, Volume 58, Issue 21, 2003, Pages 4871-4882.
D. G. Norton and D. G. Vlachos. A CFD study of propane/air microflame stability. Combustion and Flame, Volume 138, Issues 1-2, 2004, Pages 97-107.
R. Sui and J. Mantzaras. Combustion stability and hetero-/homogeneous chemistry interactions for fuel-lean hydrogen/air mixtures in platinum-coated microchannels. Combustion and Flame, Volume 173, 2016, Pages 370-386.
J. C. Ganley, E. G. Seebauer, and R. I. Masel. Porous anodic alumina microreactors for production of hydrogen from ammonia. AIChE Journal, Volume 50, Issue 4, 2004, Pages 829-834.
P. M. Torniainen, X. Chu, and L. D. Schmidt. Comparison of monolith-supported metals for the direct oxidation of methane to syngas. Journal of Catalysis, Volume 146, Issue 1, 1994, Pages 1-10.
A. Berman, R. K. Karn, and M. Epstein. Kinetics of steam reforming of methane on Ru/Al2O3 catalyst promoted with Mn oxides. Applied Catalysis A: General, Volume 282, Issues 1-2, 2005, Pages 73-83.
N. S. Kaisare and D. G. Vlachos. Optimal reactor dimensions for homogeneous combustion in small channels. Catalysis Today, Volume 120, Issue 1, 2007, Pages 96-106.
C. M. Miesse, R. I. Masel, C. D. Jensen, M. A. Shannon, and M. Short. Submillimeter-scale combustion. AIChE Journal, Volume 50, Issue 12, 2004, Pages 3206-3214.
N. S. Kaisare, S. R. Deshmukh, and D. G. Vlachos. Stability and performance of catalytic microreactors: Simulations of propane catalytic combustion on Pt. Chemical Engineering Science, Volume 63, Issue 4, 2008, Pages 1098-1116.
N. Djilali. Computational modelling of polymer electrolyte membrane (PEM) fuel cells: Challenges and opportunities. Energy, Volume 32, Issue 4, 2007, Pages 269-280.
H.-W. Wu. A review of recent development: Transport and performance modeling of PEM fuel cells. Applied Energy, Volume 165, 2016, Pages 81-106.
M. S. Mettler, G. D. Stefanidis, and D. G. Vlachos. Enhancing stability in parallel plate microreactor stacks for syngas production. Chemical Engineering Science, Volume 66, Issue 6, 2011, Pages 1051-1059.
G. D. Stefanidis and D. G. Vlachos. Millisecond methane steam reforming via process and catalyst intensification. Chemical Engineering & Technology, Volume 31, Issue 8, 2008, Pages 1201-1209.
J. Wan, A. Fan, and H. Yao. Effect of the length of a plate flame holder on flame blowout limit in a micro-combustor with preheating channels. Combustion and Flame, Volume 170, 2016, Pages 53-62.
Y. Yan, W. Huang, W. Tang, L. Zhang, L. Li, J. Ran, and Z. Yang. Numerical study on catalytic combustion and extinction characteristics of pre-mixed methane-air in micro flatbed channel under different parameters of operation and wall. Fuel, Volume 180, 2016, Pages 659-667.