Thermochemical production of bio-oil: downstream processing technologies for bio-oil upgrading, production of hydrogen, and high value-added products

R. Kumar, V. Strezov

Research output: Chapter in Book/Report/Conference proceedingChapterpeer-review


Bio-oil produced from biomass pyrolysis and hydrothermal liquefaction are considered the most sustainable alternatives for depleting fossil fuels. However, the poor bio-oil properties, such as high viscosity, presence of solid particles, low calorific value, and high instability, restrict its use as a drop-in fuel. The bio-oil properties can be significantly improved using different methods, such as catalytic upgrading, biomass pre-treatment, and downstream bio-oil upgrading. This article focuses on the widely used methods for downstream bio-oil upgrading, such as hydrotreatment, solvent addition, emulsification, microfiltration, and electrocatalytic hydrogenation. The bio-oil upgrading using non-polar solvents or preparing emulsions using surfactants has shown a significant increase in the calorific values and a considerable decrease in the viscosity of the bio-oil. On the other hand, filtration of the bio-oil using membranes can remove the char particles and alkali and alkali earth metals from the bio-oil, consequently leading to higher stability of the bio-oil. Electrocatalytic hydrogenation of the bio-oil has shown promising results in increasing the content of hydrocarbons and pH by removing the carbonyl group-containing compounds from the bio-oil. The bio-oil can also be upgraded to other clean fuels, such as H2, using a steam reforming approach, which has been critically reviewed. Basic principles of the processes and effects of different parameters on bio-oil upgrading are thoroughly discussed. In addition, techno-economic analysis, policy analysis, challenges, and future recommendations related to downstream processes are provided in the article. Overall, this chapter provides critical information about downstream bio-oil upgrading and the production of other high-value-added fuels.
Original languageEnglish
Title of host publicationBiowaste and Biomass in Biofuel Applications
EditorsSingh Yashvir, Vladimir Strezov, Prateek Negi
Place of PublicationBoca Raton, FL
PublisherTaylor & Francis
Number of pages70
ISBN (Electronic)9781003265597
ISBN (Print)9781032193588, 9781000840087
Publication statusPublished - 2023


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