Modern Strategies for the Upgrading and Catalytic Processing of Bio-Oil (Review)

Abstract

The demand for renewable energy sources has been growing steadily over the past decade. Bio-oil, a product of biomass pyrolysis, is considered a promising feedstock for the production of fuels and valuable chemicals. A practical route for converting bio-oil is to co-process it in catalytic cracking — the key technology of oil refining. Bio-oil conversion in FCC units is feasible without significant modernization or capital investment, as cracking is relatively tolerant to feedstock composition. However, processing raw bio-oil or its blends with petroleum products is not viable due to immiscibility of bio-feed with hydrocarbon feedstocks, low thermal stability, high acidity, and compositional degradation during long-term storage. These drawbacks are primarily caused by the presence of up to 40% oxygen in bio-oil. Therefore, bio-oil requires a stabilization or upgrading stage prior to refining. This review provides a detailed analysis of existing methods for the pretreatment of bio-oil for its subsequent catalytic conversion and briefly examines recent advances in the integration of upgraded products into the catalytic cracking process.