Towards an Efficient Hydrogen Production from Biomass: A Review of Processes and Materials

Concerning the enhancement of H-2 yield and selectivity, simplification of the H-2 production process, and convenience of CO2 sequestration, hydrocarbon steam reforming integrated with in situ CO2 capture is a promising pathway for the production of hydrogen-rich gas. The great potential of sorption enhanced reactions has been explored in many processes for sustainable H-2 production from biomass, such as biomass steam gasification, tar elimination, the steam reforming of sugars, bio-oil, biomass-derived oxygenates, and bio-gas, the upgrading of biomass-derived synthesis gas, etc. The experimental demonstrations and thermodynamic analysis of current relevant studies have confirmed the benefits and flexibility of sorption enhanced reforming reactions. Catalyst properties are critical with respect to maximizing H-2 yield and selectivity in the conversion of biomass or biomass-derived chemicals through integrated reactions. Preferential C-C cleavage is desirable for high selectivity to synthesis gas and a low selectivity to hydrocarbons. Based on the general principles of selective C-C cleavage, activity for the water gas shift reaction and reduction of coking potential, the guidelines for a catalyst screen are discussed with a focus on the particular requirements of sorption enhanced H-2 production. The performance of the CO2 acceptor is also important in improving H-2 production efficiency. The application challenges and new development of CaO-based materials as CO2 acceptors are also addressed.