Abstract

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 (CaO•MgO), 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.

Recommended Citation

Escobedo Bretado, Miguel; Delgado Vigil, Manuel D.; Collins Martinez, Virginia H.; and López Ortiz, Alejandro (2008) "Thermodynamic Analysis for the Production of Hydrogen through Sorption Enhanced Water Gas Shift (SEWGS)," International Journal of Chemical Reactor Engineering: Vol. 6: A51.
Available at: http://www.bepress.com/ijcre/vol6/A51