Subsection-Controlling Strategy for Improving Sorption-Enhanced Reaction Process

Abstract

The subsection-controlling strategy was applied to the design of the adsorptive reactor to improve the sorption-enhanced steam–methane reforming (SMR), by using subsection-packing ratio of adsorbent and catalyst, and subsection-controlling wall temperature. In the case of the subsection-controlling wall temperature, there is a lower operating temperature zone at the outlet of the adsorptive reactor, where the remaining CO and CO2 concentrations in gas stream can be decreased further by the principle of temperature-induced equilibrium shift. The feasibility and effectiveness of the subsection-controlling strategy for improving the sorption-enhanced steam–methane reforming process is analysed by numerical simulation based on literature data. At low operating pressure, in the range 222–445.7 kPa, combined with subsection-controlling strategy [higher temperature, 450–490°C, for subsections I (inlet zone of the adsorptive reactor) and II (middle zone of the adsorptive reactor) and lower temperature, 400–450°C, for subsection III (outlet zone of the adsorptive reactor); lower packing ratio of adsorbent and catalyst for subsections I and III and higher ratio for subsection II] a product gas with hydrogen purity above 85% and traces of CO2 (less than 300 ppm) and CO (less than 30 ppm) can be continuously produced with higher hydrogen productivity by a four-step one-bed (a 6 m long adsorptive reactor) pressure swing sorption-enhanced steam–methane reforming cyclic process, and may be directly used in fuel cell applications.