Sorption-enhanced reaction process with reactive regeneration

Sorption-enhanced reaction process with reactive regeneration of adsorbent was proposed where the purge step is performed at a low temperature of 400degreesC (compared with the reaction temperature of 450degreesC) with 10% H-2 in nitrogen under atmospheric pressure. Hydrogen-enriched stream with traces Of CO2 and CO can be produced by steam-methane reforming. A mathematical model taking into account multicomponent (six species) mass balances, overall mass balance, Ergun relation for the pressure drop, energy balance for the bed-volume element including the heat transfer to the column wall, and nonlinear adsorption equilibrium isotherm coupled with three main reactions was derived to describe this new cyclic process. The feasibility and effectiveness of this cyclic process is analyzed by numerical simulation. The results show that using either a 4 m or a 6 m long adsorptive reactor (depending on the operation time of the first step), a product gas with above 88% hydrogen purity and traces Of CO2 and CO (CO less than 30 ppm) can be continuously produced and directly used in the fuel cell applications. The validity of the model prediction was checked by comparing the simulated results with experimental data from the literature where the regeneration of adsorbent is carried out by steam purge at subatmospheric pressure. The model results qualitatively agree with experimental data. The package is needed to improve the design and analysis of sorption-enhanced reaction process. (C) 2002 Elsevier Science Ltd. All rights reserved.