Co-production of high quality hydrogen and synthesis gas via sorption-enhanced steam reforming of glycerol coupled with methane reforming of carbonates

摘要

The sorption enhanced steam reforming (SESR) produces high-purity hydrogen and capture CO2 in the form of carbonates, allowing for controllable CO2 storage or utilization. However, the decarbonation of carbonates at temperatures high up to 800-900 degrees C makes the SESR process and the subsequent CO2 utilization energy-intensive. Herein, we report the feasibility coupling the SESR of glycerol with CH4 reforming of carbonates, which combines the decarbonation with CO2 utilization to simplify the technology and avoid the energy-consuming temperature swing. A high-efficiency bi-functional Ni-CaO-Ca12Al14O33 catalyst was proposed to this process. The catalyst was derived from a Ni-Ca-Al hydrotalcite-like (HT1) material to achieve homogeneous mixing of Ni, CaO and Ca12Al14O33 which were active metal, sorbent and a spacer to prevent CaO sintering. Thanks to the high activity and stability of Ni-CaO-Ca12Al14O33 catalysts, 98.53% hydrogen-enriched gas could be obtained in SESR of glycerol, and the high CH4 conversion (95.3%) and H-2/CO molar ratio (< 2) suitable for further Fisher-Tropsch synthesis were achieved during the CH4 reforming reaction. Meanwhile, Ca12Al14O33 as a spacer had provided a stability for ten cycles. Our results highlight the significance of process intensification and high-efficiency bi-functional catalysts for the hydrogen production with low carbon emissions.