Recent advances on strategies for upgrading biomass pyrolysis vapour to value-added bio-oils for bioenergy and chemicals

Abstract

Researchers have identified biomass feedstocks and pyrolysis techniques that produce biofuels and chemicals from sources other than fossil fuels. Algae, organic solid tannery waste, and forest and agricultural wastes have been viable feedstocks. This paper pioneered a comprehensive discussion of the strategies used to produce bio-oils for fuel and chemicals from biomass pyrolysis. Specifically, the catalytic upgrading, co-pyrolysis, temperature-programmed pyrolysis, and biomass pre-treatment strategies and their relationships were extensively reviewed in this paper. The strategies are beneficial, as the bio-oils produced are rich in hydrocarbons and aromatics, leading to higher calorific values than those of the biomass feedstocks and raw bio-oils. The pre-treatment technique's discouraging drawbacks included high costs, secondary waste production, and constituent loss. Also, the review revealed that co-pyrolysis could be expensive and problematic because it necessitates the simultaneous supply of scarce feedstock. The potential of bio-oils for fuel and chemicals was increased by microporous zeolites and their composites. The bio-oils have high calorific values and high concentrations of aromatics and hydrocarbons due to the use of microporous zeolite catalysts. These zeolites’ noteworthy drawbacks include their small, easily blocked pores and early deactivation. In the future, high-grade bio-oils will require mesoporous, highly functionalized ZSM-5 derived from inexpensive materials.