A modified process for overcoming the drawbacks of conventional steam methane reforming for hydrogen production: Thermodynamic investigation

In this novel work, application of CaO sorption enhanced steam methane reforming (SESMR) for promoting hydrogen production thermally coupled with chemical looping combustion (CLC) instead of furnace for CO2 capture has been investigated to modify the conventional SMR process. In this novel process, CLC is employed to provide the necessary heat for SESMR, simultaneously achieving inherent separation of CO2 without extra energy consumed. This unprecedented technique was developed and calculated using Aspen Plus and it has been found to be favored by operating under conditions of stem to methane ratio (S/C) = 4, CaO to methane ratio (Ca/C) = 1 and reforming pressure of 25 bar. The competitiveness of this novel configuration shows excellent advantages against dominant industrial SMR process including promoting H2 purity of product gas to be 92.6% without extra process to separate impurities from product gas, simultaneously decreasing CO and CO2 concentrations from 0.2% and 2.4% to ppm level. The overall energy efficiency of SMR and this suggested process is calculated equal to 68.02% and 85.50%, respectively; approximately 17.48% of energy efficiency is benefited from this novel process. The heat load analysis for reforming process suggests that the Ca-based sorption enhanced steam reforming process can achieve autothermal operation.