Catalytic interventions in bio-oil production from lignocellulosic biomass and Co-processing with petroleum refinery fractions: A review

The global demand for alternative renewable fuels and chemicals has fascinated researchers to look out for biooil derived from lignocellulosic biomass. The unmediated usage of bio-oil is restricted due to its undesirable qualities, including high oxygen content, high corrosivity, and low thermal stability. To enhance the properties of bio-oil, catalytic intervention is very much needed during pyrolysis or liquefaction. In addition, building a grassroot refinery for bio-oil processing is economically not viable. In the existing petroleum refineries, several valuable products (olefins, aromatics, LPG, gasoline, kerosene, and diesel) are being produced from low-value feedstock (crude oil, vacuum gas oil, and vacuum residue) to improve the economics. An alternative approach is proposed to co-process bio-oil with petroleum refinery fractions in the existing petroleum refineries. Lignocellulosic biomass is available in vast quantity globally so this approach might act as a substitute to decrease the dependence on fossil fuels in a sustainable way. Co-processing can be achieved by understanding the conversion processes and their mechanistic pathways. This study reviews the available literature on different thermochemical conversions, namely, fast pyrolysis, catalytic pyrolysis, hydrothermal/solvothermal liquefaction, and hydrodeoxygenated bio-oil and co-processing of this bio-oil through fluid catalytic cracking and hydrotreating. Co-processing challenges and research gaps have also been indicated for future exploration.