Production of Biofuels via the Catalytic Cracking of Mixtures of Crude Vegetable Oils and Nonedible Animal Fats with Vacuum Gas Oil

Vegetable oils (crude palm oil and crude soybean oil), nonedible animal fats, and waste cooking oil (WCO) were mixed with a standard gas oil and tested under fluid catalytic cracking (FCC) conditions in a short-contact-time microactivity reactor using an industrial FCC equilibrium catalyst. Under the reaction conditions tested in this work, triglyceride molecules are completely transformed into water, CO2, CO, and a mixture of hydrocarbons. The presence of a triglyceride-based biomass in the feedstock of a FCC unit reduces the yield toward liquid products and enhances gas and coke formation. Likewise, the cracking of oil and fats in the FCC conditions increases aromatic hydrocarbon formation. This fact comes from oxygen removal of the initial triglycerides to form water as the principal oxygenated compound, which requires the presence of hydrogen molecules coming from the transformation of hydrocarbons into olefins. These olefins, in the severe reaction conditions under study, will tend to form aromatic hydrocarbons. Likewise, preliminary catalytic results described in this work show that unsaturated renewable raw materials (such as soybean oil or WCO) lead to an increase in the concentration of aromatic compounds for the liquid phase as compared to that found for the most saturated feedstocks (palm oil and animal fats). Moreover, a slightly higher yield toward the liquid products and lower gaseous compound formation are also evidenced with the most unsaturated triglyceride-based feed.