Integration of different strategies to increase the bio-oil quality and yield during fluidized bed fast pyrolysis of lignocellulosic biomass

Pyrolysis based refineries have great potential to convert waste polymeric material such as plastic and biomass waste into 'drop-in' feedstocks for refineries as well as energy, to achieve maximum economic and environmental benefits. Fast pyrolysis of biomass has gained much attention as an effective pathway to produce valuable bio-oils which are green alternatives to crude oil in the production of liquid fuels, platform chemicals and materials. Bio-oil is an attractive biogenic intermediate that can be transported and stored more easily that raw biomass, fitting well into energy, transportation fuel logistics and supply chains, much like available commodities on the market. The heart of the process is the pyrolyzer and fluidized bed reactors are excellent candidates providing superior thermal performances and contacting patterns. The composition and yields of bio-oils depend on process operating parameters, reactor configuration and feedstock type. A key feature of raw bio-oils is their inherently large oxygen content which makes them quite different from petroleum fuels as regards to oxygenated moieties, hydrophilicity, viscosity and acidic nature. Heterogeneous catalysis is an effective tool to promote oil deoxygenation and upgrade. The use of fluidized bed reactors enables effective in situ contact between the catalyst and vapours originated from biomass thermal decomposition, with minimal additional complexity and cost as compared to the non-catalytic process. Co-pyrolysis of biomass with hydrogen-enriched feedstock (e.g. plastics waste) has been explored to promote bio-oil deoxygenation and to enhance selectivity to hydrocarbons. This study reports on an ongoing project aiming at producing high-quality bio-oil from pyrolysis of biomass, pursued by integration of several measures: a) carefully optimized design and operation of the pyrolyzer, b) use of catalyst for in-bed oil upgrade, c) co-pyrolysis with organic scrap materials, d) biomass pre-treatment.