Co-processing of FCC light cycle oil and waste animal fats with straight run gas oil fraction

Abstract

In the European Union the demand for middle distillates is growing, while decrease in the gasoline demand can be observed. Even the most complex refineries are not able to produce the economic yield distribution from the processed crude oil which constantly meets the changing market demand. The growing need of diesel fuel can only be satisfied by using unconventional feedstocks, such as bio-originated resources and less valuable refinery streams (e.g. light cycle oil with high aromatic content, >80%, from Fluid Catalytic Cracker).The aim of our experiments was the investigation (co-processing) of differently prepared mixtures from straight run gas oil (70–100%), light cycle oil (LCO: 0–10%) and waste animal fat (0–20%). There are no publicly available articles which present the use of these feedstock components. We investigated the effects of the process parameters (temperature: 300–380 °C, pressure: 40–70 bar, liquid hourly space velocity (LHSV): 0.75–2.0 h−1, H2/feedstock ratio: 600 Nm3/m3) on the quality and quantity of products obtained from different composition feedstocks. We found that with the usage of favourable parameter combination the total conversion of triglycerides and free fatty acids (FFA) into n-paraffins as well as the saturation of a significant part of the aromatic compounds and the desulphurisation of the LCO and straight run gas oil can be reached. Notable quality improvement was observed in case of all feedstock components at co-processing. High cetane number of alkanes formed from the conversion of triglycerides and FFAs, compensating the low cetane number of products (e.g. monoaromatics and diaromatics) from the saturation of polyaromatic components. Products obtained at advantageous process parameters can be excellent diesel fuel blending components, because they have low sulphur and aromatic content as well as adequate cetane number, density and cold flow properties. Besides these, they contain components from renewable sources, too.