Efficient recovery of syngas from dry methane reforming product by a dual pressure swing adsorption process

Abstract

In recent years, there has been growing interest in the dry reforming of methane (using CO2 instead of H2O) to obtain syngas, due to its economic and environmental advantages. In this reaction, to achieve conversions close to 100%, it is necessary to work at temperatures higher than 1000 °C. However, to attenuate the catalyst deactivation by sintering is convenient to work at lower temperatures, so that normally the syngas (mixture CO + H2) is obtained mixed with unreacted CO2 and CH4. In this work a process has been simulated to recover the syngas from the product of a dry reforming reaction of methane at 700 °C by means of a Dual PSA (Dual Pressure Swing Adsorption) process with heavy reflux using BPL activated carbon as an adsorbent, operating at 25 °C. The process can recover syngas with purity and recovery higher than 99%. Unreacted CO2 and CH4 can be recycled to the reactor, leading to effective CO2 and CH4 conversions close to 100%. The process specific energy input (SEI) is 4.7 thermal kJ per L (STP) of syngas. The process can also be used to recover the syngas contained in the tail gas of a H2 purification PSA from SMR-off gas.