Green hydrogen production from sorption-enhanced steam reforming of biogas over a Pd/Ni–CaO-mayenite multifunctional catalyst

Abstract

The carbon-neutral application of biogas to produce “green hydrogen” appears to be an attractive solution to ensure the sustainability of energy production. However, the high and variable CO2 content in biogas has limited the development of biogas utilization. Herein, we report that sorption-enhanced steam reforming of biogas (SESRB) provides an efficient way to obtain high-purity hydrogen from biogas with the in-situ removal of CO2. The effect of temperature and CO2 content on CH4 conversion and H2 purity is studied. The results indicate that the content of CO2 does not affect the CH4 conversion and H2 purity in the pre-breakthrough stage of SESRB process. Meanwhile, the performance of long-term stability shows that 98.0 vol% H2 with ⁓97.8% conversion of CH4 in the pre-breakthrough stage is stably obtained over the Pd/Ni–CaO-mayenite-2.8 multifunctional catalyst for 30 SESRB-calcination cycles. The small amount of coke (0.8 wt%) formed during the SESRB reaction can be effectively eliminated by carbon gasification during calcination treatment. The results point out that SESRB is a promising technology for the efficient utilization of biogas to produce high-purity hydrogen.