Co-processing bio-oil in the refinery for drop-in biofuels via fluid catalytic cracking

Pyrolysis oil from lignocellulosic biomass (bio-oil) is a promising renewable energy carrier that can be utilized for the production of second-generation drop-in biofuels. Co-processing bio-oil with petroleum feeds in existing refinery processes, such as fluid catalytic cracking (FCC), has been proposed as a cost-effective way of transitioning to the production of such biofuels without the need for significant capital-intensive investments. Several routes are available for the production of bio-oil, such as fast pyrolysis of biomass (raw bio-oil), catalytic fast pyrolysis of biomass (catalytic pyrolysis oil, CPO), and fast pyrolysis of biomass followed by hydrogenation of the produced bio-oil (hydrodeoxygenated oil, HDO). Research has shown that co-processing raw bio-oil is challenging but it can be carried out after adoption of appropriate reactor modifications in the commercial scale. A significant body of work has also focused on the co-processing of HDO and CPO, and has demonstrated that these types of bio-oil can be co-processed with less operational issues. Co-processing bio-oil results in a liquid hydrocarbon product that contains only a small amount of oxygenates from bio-oil. A noticeable increase in coke formation is also observed when bio-oil is introduced in the FCC feed. However, this increase is lower than what would be expected from the conversion of the pure bio-oil fraction. This has been attributed to the presence of the petroleum feed, which has a beneficial synergistic effect on the cracking of bio-oil due to hydrogen donation reactions that inhibit coke formation and promote the conversion of the oxygenates to liquid hydrocarbons. This article is categorized under: Energy and Climate > Climate and Environment Bioenergy > Systems and Infrastructure Bioenergy > Economics and Policy.