An experimental study on carbon monoxide conversion and hydrogen generation from water gas shift reaction

The characteristics of carbon monoxide conversion and hydrogen generation from a water gas shift reaction (WGSR) are investigated experimentally. Particular emphasis is placed on the performance of the reaction affected by various operational conditions. The important parameters include the catalyst type, residence time of reactants in a catalyst bed, reaction temperature and CO/steam ratio. Two different catalysts, consist of a high-temperature catalyst (HTC) and a low-temperature catalyst (LTC), are taken into consideration. The experiments indicate that when the residence time is as long as 0.09 s, the WGSR develops well, no matter which catalyst is used. With the effect of the HTC, increasing reaction temperature will promote the performance of the WGSR. Alternatively, for the LTC, the reaction will not be excited if the reaction temperature is below 200 °C. Once the temperature reaches 200 °C the reaction occurs, but the CO conversion decreases with increasing temperature. These behaviors reveal that the water gas shift reactions with the HTC and the LTC are governed by chemical kinetics and thermodynamic equilibrium, respectively. It is of interest that water decomposition also develops in the WGSR so that the concentration of H2 is always higher than that of CO2 a bit. With regard to the CO/steam ratio, the CO conversion will be enhanced if the ratio is decreased. However, the performance of the WGSR is insensitive to the variation of the ratio if it is smaller than 1/4.