Subsection-controlling strategy for improving sorption-enhanced reaction process

摘要

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 CO_2 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 deg C,for subsections I (inlet zone of the adsorptive reactor)and II (middle zone of the adsorptive reactor)and lower temperature,400-450 deg 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 CO_2 (less than 300 ppm)and CO (less than 30ppm)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.