International Journal of Hydrogen Energy, Vol.37, No.19, 14167-14177, 2012
Entropy generation from hydrogen production of catalytic partial oxidation of methane with excess enthalpy recovery
Catalytic partial oxidation of methane (CPOM) is an important route for producing hydrogen and it is featured by autothermal reaction. To recognize the reaction characteristics of CPOM, H-2 production and entropy generation from CPOM in Swiss-roll reactors are studied numerically. The considered parameters affecting the performance of CPOM include the excess enthalpy recovery, gas hourly space velocity (GHSV), number of turns and atomic O/C ratio. The impact of chemical reactions, heat transfer and friction on entropy generation is also analyzed. The results indicate that preheating reactants through waste heat recovery as well as increasing GHSV or number of turns is conducive to enhancing H-2 yield, whereas the maximum H-2 yield develops at O/C = 1.2. A higher H-2 yield is always accompanied by a higher value of entropy generation, and chemical reactions are the main source of entropy generation, especially from steam methane reforming. In contrast, viscous dissipation almost plays no part on entropy generation, compared to heat transfer and chemical reactions. From the analysis of entropy generation, detailed mechanisms of H-2 production from CPOM can be figured out. Copyright (C) 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.
Keywords:Hydrogen production and entropy generation;Catalytic partial oxidation of methane (CPOM);Steam reforming and dry reforming;Swiss-roll reactor;Excess enthalpy recovery