Sorption-enhanced steam gasification of biomass for H2-rich gas production and in-situ CO2 capture by CaO-based sorbents: A critical review

Abstract

The sorption-enhanced steam gasification of biomass (SEBSG) is considered a prospective thermo-chemical technology for high-purity H2 production with in-situ CO2 capture. Fundamental concepts and operating conditions of SEBSG technology were summarized in this review. Considerable industrial demonstration units have been conducted on pilot scales for large-scale availability of the SEBSG process. The influence of process parameters such as reaction temperature, Steam/Biomass (S/B) ratio, feedstock characteristics, cyclic CO2 capture capacity of CaO-based sorbents, and catalysis, were critically reviewed to provide theoretical recommendations for industrial operation. Bifunctional materials that have high catalytic activity and CO2 capture activity are crucial for ensuring high H2 production in the SEBSG. The application of density functional theory (DFT) and reactive force field molecular dynamic (ReaxFF MD) simulations on microcosmic reaction mechanisms in the SEBSG process, such as pyrolysis, WGS and reforming reactions, and CO2 capture of CaO-based materials are comprehensively overviewed. Several research gaps, like the exploitation of more efficient and low-cost bifunctional material, integrated process economics and revelation of well-rounded mechanisms, need to be filled for the following large-scale industrial applications.