A review on biomass as a substitute energy source: Polygeneration influence and hydrogen rich gas formation via pyrolysis

Hydrogen rich gas production and advantages of polygeneration during biomass conversation through pyrolysis were extensively reviewed in this paper. Different innovative pyrolysis setups and the effect of reaction conditions such as pressure, temperature, catalyst type, biomass type, and reactor type on the formation of hydrogen and other value-added chemicals has been exploited. High temperatures and pressures together with application of catalysts was reported to favour the enhancement of hydrogen by promoting secondary pyrolysis reactions and hence the production of H₂ gas. Compared to one-stage pyrolysis systems, pyrolysis data from two-stage pyrolysis reaction systems reported improved production of hydrogen and value-added chemicals due to the reforming of volatile matter in the second stage reactor. The polygeneration effect of biomass pyrolysis has also been reviewed, and it was observed that the polygeneration systems were significantly vital in covering the demand and supply of renewable energy.