De Gruyter, International Journal of Chemical Reactor Engineering, 1(6), 2008
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A thermodynamic analysis for the process concept of hydrogen production based on the combination of the water gas shift (WGS) and CO2 capture reactions (Absorption Enhanced Water Gas Shift, SEWGS) is presented. The chemical equilibrium analysis of this reaction system was performed to select the proper CO2 absorbent among: calcined dolomite (CaOMgO), Li4SiO4 and Na2ZrO3 to be used in the process. Results indicate that the use of Na2ZrO3 produced the highest hydrogen concentration among absorbents studied. Results also revealed that the maximum hydrogen concentration (97% mol) can be achieved with a feed molar ratio of CO/Na2ZrO3/H2/O = 1/1/2 at 500°C at atmospheric conditions. The use of a catalyst for such processes may not be needed, since the high temperature at which these reactions are proposed may promote homogeneous non-catalyzed reactions. However, if the combination of both reaction kinetics (WGS and carbonation) are not fast enough to reach equilibrium, a new non-conventional WGS catalyst may be needed.