Characterization of water gas shift reaction in association with carbon dioxide sequestration

The characteristics of a water gas shift reaction (WGSR) in association with carbon dioxide sequestration under the effects of a high-temperature catalyst (HTC) and a low-temperature catalyst (LTC) are studied experimentally. With the condition of fixed residence time (0.1 s) for the reactants in the catalyst bed, it is found that the reaction behaviors with the HTC are inherently different from those with the LTC. Specifically, for the WGSR with the HTC, the reaction can be divided into a rapid growth regime, a progressive growth regime and a slow growth regime with increasing reaction temperature or steam/CO ratio. With regard to the WGSR with the LTC, three different regimes are also exhibited; however, they consist of a rapid growth regime, a progressive decay regime and a growth-frozen regime. According to the aforementioned characteristics, proper or better operation conditions using the HTC and the LTC for the application of fuel cells are suggested. When the product gas passes through a Ca(OH)₂ solution, the obtained results reveal that CO₂ removal efficiency increases with increasing solution concentration or steam/CO ratio for both the HTC and the LTC used in the WGSR.