화학공학소재연구정보센터
AIChE Journal, Vol.48, No.12, 2817-2832, 2002
Simulation of five-step one-bed sorption-enhanced reaction process
A five-step, one-bed, sorption-enhanced reaction process proposed by Carvill et al. in 1996 for hydrogen production by steam - methane reforming was analyzed. For the simulated results of the first step, data from Hufton et al. (1999) and Ding and Alpay (2000) for a fixed-bed column of an admixture of a catalyst and a sorbent that selectively removes CO2 from the reaction zone were used. The sorbent is periodically regenerated by using the principles of pressure-swing adsorption. The process steps allow direct production of hydrogen with high purity and high methane conversion. A model considering multicomponent and overall mass balance, Ergun relation for pressure drop, energy balance for the bed-volume element, and nonlinear adsorption equilibrium isotherm coupled with three main reactions was derived to describe the sorption-enhanced reaction cyclic process. Two different isotherms were used under wet and dry conditions. The LDF model adopted describes the mass-transfer rate of CO2 in the adsorbent. Numerical solution of model equations for the cyclic process was obtained by the orthogonal collocation method. The operating conditions allow the combination of a sufficiently high purity of hydrogen (average purity over 80%) with traces of CO and CO2, high methane conversion, fast adsorbent regeneration, and cyclic steady-state operation. The model predictions agree reasonably with the literature data. The package is suitable for the design and analysis of sorption-enhanced reaction process.