Preparation of Feedstock (Atmospheric Residue) for the Fluidized Catalytic Cracking (FCC) Process: A Case of the Zinder Refining Company

Abstract

The Fluid Catalytic Cracking unit (FCC) is a key process that plays an important technical and economic role in the refining industry. Over the past years, there has been an increased interest in applying advanced process modelling and control that would lead to a significant economic benefit of FCC operation. This study presents a summary of the study on the preparation of a feedstock (atmospheric residue) from the RFCC unit (fluidized catalytic cracking process). The atmospheric residue, being the last cut drawn from the bottom of the atmospheric distillation column at a high boiling point > 350°C, may contain many impurities such as solids content, density, metal content, water content, residual carbon, etc. However, to ensure proper fluid catalytic cracking operation, it is necessary to characterize it to determine the appropriate type of preliminary treatment. Thus, the main objective of this study was to characterize the feedstock (atmospheric residue). In the environmental context, the characterization of the feedstock gave us an overall idea of its susceptibility to producing atmospheric pollutants such as SOX, COX, and NOX and allowed us to predict the severity of the cracking process in order to reduce the emission of these pollutants and limit coke formation. The characterization results, such as density at 15°C (925.52 kg/m³), residual carbon (6.842% mass), iron content (0.965 mg/kg), nickel content (24.905 mg/kg), vanadium content (0.385 mg/kg), lead content (0.09 mg/kg), copper content (0.06 mg/kg), calcium content (0.74 mg/kg), led to the conclusion that the FCC unit feedstock is ready to be sent to the FCC unit. The adverse impact on the cracking process, the environment, and the quality of the resulting products is minimal. The results also allowed us to conclude that the metal contents determined in the atmospheric residue studied have a low degree of contamination. This has earned Niger's atmospheric residue exceptional quality, making it much more competitive in international markets.