Combined slow pyrolysis and steam gasification of biomass for hydrogen generation-a review

Hydrogen, the inevitable fuel of the future, can be generated from biomass through promising thermochemical methods. Modern-day thermochemical methods of hydrogen generation include fast pyrolysis followed by steam reforming of bio-oil, supercritical water gasification and steam gasification. Apart from the aforementioned methods, a novice technique of employing combined slow pyrolysis and steam gasification can be also engaged to produce hydrogen of improved yield and quality. This review paper discusses in detail about the existing hydrogen generation through thermochemical methods. It elaborates the merits and demerits of each method and gives insight about the combined slow pyrolysis and steam gasification process for hydrogen generation. The paper also elaborates about the various parameters affecting integrated slow pyrolysis and steam gasification process.