High temperature CO2 sorbents and their application for hydrogen production by sorption enhanced steam reforming process

Among the available techniques for hydrogen production, the sorption enhanced steam reforming (SESR) is an emerging technology consisting in the integration of reforming reaction (H2 production) and selective separation (CO2 sorption) in a single step, to shift thermodynamically the reforming reaction and increase hydrogen production. It is a forefront technology to produce highly pure hydrogen that has several advantages against the conventional steam reforming operation. The key element for a successful SESR process is the selection of suitable high-temperature CO2 sorbents. Due to the weakness of current CO2 sorbents (capacity decay and/or slow kinetics), the improvement of their performance is crucial to make the SESR process interesting for industrial applications. This review focuses on the main characteristics and preparation methods of CaO-based and alkaline-based sorbents, their advantages and drawbacks, the available techniques to improve their behavior in severe operating conditions, as well as the progress of their application in two important SESR processes, namely sorption enhanced steam methane reforming (SESMR) and sorption enhanced steam glycerol reforming (SESGR).