Asian Journal of Biotechnology and Bioresource Technology

For several years now, the oil market has been transforming in the face of growing global demand for fuels, while at the same time, demand for heavy fuel oil is declining (Danial-Fortan, 2010). At the same time, dwindling conventional oil resources are gradually being replaced by increasingly heavier oils, such as tar sands. To respond to this market trend, it is essential to valorise these oil residues by converting them into lighter fractions. This article presents a literature review on the study of the role of catalysts in fluid catalytic cracking of atmospheric residues. It consists of three main parts: the first deals with crude oil and the various refining processes, the second with the various catalytic cracking processes and the study of the FCC unit, and the third with the study of some industrial catalysts and their impact on the performance of the FCC unit. Crude oil, a complex mixture of hydrocarbons and a few metals, is one of the world's most important sources of energy. In its crude state, it cannot be used by consumers. It must therefore undergo the first transformation (atmospheric or fractional distillation) in order to fractionate it into different fractions or cuts. Likewise, some of these fractions require further purification and quality improvement treatments, such as catalytic cracking in fixed, moving and fluidised beds, etc. Fluid catalytic cracking (the most widely used of all catalytic processes), a process for converting high-molecular-weight petroleum fractions into low-molecular-weight fractions in the presence of a catalyst, is one of the most important conversion processes in a refinery. The catalyst is a species that accelerates a chemical reaction and is not found in the reaction products, so it plays an essential role in catalytic cracking reactions. FCC unit catalysts are generally based on Zeolite, which comes in several types, the assembly of noble metals such as Ni, Co, Mo, W,..., supported by alumina. The efficiency or yield of the unit depends on the operating conditions (temperature and pressure), the feedstock, such as atmospheric residue, vacuum residue, vacuum diesel, etc., and the catalyst used. The FCC products reported by most researchers are LPG, gasoline, diesel and coke, whose yield in gasoline is the highest conversion rate. Apart from all the above, this study also presents a state of the art on the various techniques for analysing heavy petroleum products and residues.