FCC coprocessing oil sands heavy gas oil and canola oil. 1. Yield structure

摘要

Reducing the carbon footprint or GHG emissions is a major challenge during the production and processing of Canadian oil sands bitumen for clean transportation fuels. Co-processing bitumen derived feeds and biomass may provide an alternative solution since the level of GHG emissions for producing renewable biofuels is considered significantly lower than that for fossil fuels. In many developed countries, it is required that biofuels replace from 6% to 10% of petroleum fuels in the near future. Co-processing biomass and bitumen feeds can use existing refining infrastructure and technologies, saving capital and operating costs. In addition, co-processing may generate synergies that improve gasoline and diesel qualities. The current study investigates the catalytic cracking performances of pure heavy gas oil (HGO) derived from oil sands synthetic crude and a mixture of 15 v% canola oil in HGO using a commercial equilibrium catalyst under typical FCC conditions. Cracking experiments were performed using a bench-scale Advanced Cracking Evaluation (ACE) unit at fixed weight hourly space velocity (WHSV) of 8 h(-1), 490-530 degrees C, and catalyst/oil ratios of 4-12 g/g. Higher conversion, dry gas yield, and liquefied petroleum gas (LPG) yield were observed at a given catalyst/oil ratio when cracking the HGO/canola oil blend compared with pure HGO. The increase in dry gas yield can be attributed to the decarboxylation and decarbonylation reactions in the presence of triglycerides composed of fatty acids in the feed, leading to the formation of CO2 and CO. In general, at a given conversion, the addition of canola oil resulted in lower gasoline yield at the expense of water formation. As well, lower coke yield was observed for the blend. The relatively high nitrogen content in the feeds played an important role in catalyst activity and selectivity, particularly at low reaction temperatures. (C) 2015 Crown Copyright and ELSEVIER Ltd. Published by Elsevier Ltd. All rights reserved.