A review of biomass pyrolysis gas: Forming mechanisms, influencing parameters, and product application upgrades

[Display omitted] •Pyrolysis of biomass to produce pyrolysis gas can be used in various areas, such as gas fuels.•The individual gas components of the pyrolysis gas are mostly environmentally friendly.•Most biomass feedstocks used for pyrolysis are carbon-cycle compliant and recyclable.•Most of the gases in the PG have a high calorific value and can be used for product upgrading. Biomass energy has become the fourth largest energy source following coal, oil, and natural gas due to its abundantly available sources. At present, pyrolysis oil and biochar are the main products of biomass pyrolysis for applications. Despite this, biomass products still have an untapped potential that deserves further exploration. Research on biomass pyrolysis gas has progressed gradually and is reaching a commercial level through deeper research. It is possible to purify and decoke pyrolysis gas into different gaseous products according to demand, and its components can also be separated and extracted for other purposes. Therefore, biomass pyrolysis gas has a great deal of potential for development. This paper reviews the mechanism of biomass transformation into pyrolysis gas, equipment, the influence of process parameters, analysis methods, potential applications of pyrolysis gas, and ideas for future pyrolysis gas product upgrading.