Catalytic Upgrading of Wood Bio-Oil and Co-Processing with Petroleum Vacuum Gas Oil.
Date
2022-09
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Abstract
Wood waste is inexpensive and a promising source for bio-oil synthesis as an alternative to decrease carbon intensity (CI) in liquid fuels. However, due to the highly reactive oxygenated compounds present in raw bio-oil, it is corrosive, thermally unstable, and has a low heating value. Bio-oil needs to be upgraded before it could be used as a fuel or mixed with petroleum products, a well-known upgrading process in the petroleum industry is hydrotreating (HDT); however, its effectiveness in heteroatoms removal, hydrogen to carbon ratio improvement, and enhancing of oil properties demand high-pressure hydrogen and consumption implying higher operational costs. The research group of Catalysis for adsorption, fuels, and energy (CAFE), in partnership with Steeper Energy, has been implementing a new bio-oil upgrading scheme. Under that path after initial HDT, further upgrading is carried out through Aquaprocessing (AQP), a Catalytic Steam Cracking (CSC) process comprising cracking and olefins hydrogenation. A distillation stage was evaluated before CSC to process heavier cuts, aiming to increase conversion and light production, however, it was found that the presence of the light fraction in CSC favoured the vacuum residue (VR) conversion. Even though most of the oxygenated compounds are removed in HDT, after CSC there is still a 3% oxygen content remaining mainly as phenol species. To further hydro-deoxygenation and increase diesel fraction quality, an additional HDT of the light fraction was implemented achieving up to 93% in phenols reduction. As a complement to this upgrading path, the co-processing of bio-oil with petroleum derivatives is a promising opportunity for biofuel producers and refineries because it offers the possibility to upgrade the biocrude with no, or insignificant investment. HDT of raw Hydrofaction™ bio-crude was co-processed with a heavy vacuum gas oil (HVGO) in a weight percent ratio of 5/95, respectively. After 90 hours of continuous operation, the co-processing was stable and 100% of total acid number (TAN) reduction was achieved, sulfur was decreased by 55% and nitrogen by 40%. After the co-processing, CSC was carried out for further nitrogen and sulphur reduction and most importantly, to produce hydrogen as a byproduct that could be recycled in HDT.
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Keywords
Bio-Oil, Upgrading, Hydrotreating, Co-processing, Catalysis, Advanced Bio-fuel
Citation
Santana Tijo, N. (2022). Catalytic upgrading of wood bio-oil and co-processing with petroleum vacuum gas oil (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.