Modeling and simulation of water-gas shift in a heat exchange integrated microchannel converter

• Published in: International journal of hydrogen energy 2018, Vol.43 (2), p.1094-1104
• Main Authors: Bac, Selin, Keskin, Seda, Avci, Ahmet K.
• Format: Article
• Language: English
• Subjects: Hydrogen; Microchannel; Modeling; Process intensification; Water-gas shift
• ISSN: 0360-3199; 1879-3487
• DOI: 10.1016/j.ijhydene.2017.09.141

The aim of this study is to analyze the operation of a heat exchange integrated, Pt-CeO2/Al2O3 washcoated microchannel water-gas shift (WGS) reactor under fuel processing conditions by mathematical modeling techniques. In this context, operation of a single microchannel is modeled, whose outcomes are compared with experimental data obtained from the literature. Simulations show good agreement with the experimental data, with an error below 4%. Upon its validation, single channel model is used to simulate a heat exchange integrated microchannel reactor, which involves periodically located groups of reaction and air-fed cooling channels. The integrated reactor is modeled by 2D Navier-Stokes equations together with reactive transport of heat and mass. Incorporation of heat exchange function minimizes the impact of thermodynamic limitations on WGS by precise regulation of reaction temperature and gives 77.6% CO conversion, which is 67.4% in the absence of cooling. Improvement in conversion from 69.2% to 77.6% is observed upon increasing feed temperature of the reaction stream from 565 to 595 K, above which the reaction is controlled by equilibrium. Coolant feed temperature, however, changes conversion only by