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

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.