 Corresponding author: Obumneme Onyeka Okwonna; ORCID ID: 0000-0001-8517-4541 Copyright © 2023 Author(s) retain the copyright of this article. This article is published under the terms of the Creative Commons Attribution Liscense 4.0. Catalyst deactivation and the effect of catalyst makeup on the FCC unit Obumneme Onyeka Okwonna 1, 3, * and Amalate Ann Obuebite 2, 3 1 Department of Chemical Engineering, University of Port Harcourt, PMB 5323, Port Harcourt, Rivers State, Nigeria. 2 Department of Petroleum Engineering, Niger Delta University, PMB 071, Wilberforce Island, Bayelsa State, Nigeria. 3 Africa Centre of Excellence for Oilfield Chemicals Research (ACE-CEFOR), University of Port Harcourt, PMB 5323, Port Harcourt, Rivers State, Nigeria. Global Journal of Engineering and Technology Advances, 2023, 14(02), 061–079 Publication history: Received on 02 January 2023; revised on 12 February 2023; accepted on 14 February 2023 Article DOI: https://doi.org/10.30574/gjeta.2023.14.2.0028 Abstract One of the significant processes of the crude oil refining process is the fluid catalytic cracking (FCC) unit. This unit produces olefins and other feedstock for the petrochemical industry as well as high octane gasoline, naphtha, light cycle oil, and heavy cycle oil. Attrition is one of the forms of catalyst deactivation on FCC catalyst which affects its operation, thereby giving rise to a high amount of catalyst makeup to compensate for the losses in this unit. This study investigated the effect of catalyst attrition on a commercial FCC unit through an analysis of its technical data from 4-run operations. The catalyst loss profile was evaluated while the scanning electron microscopy (SEM) showed abrasion as the dominant attrition type in the unit, hence resulting in many catalyst particles being lost as micro fines through elutriation. A simulation study was carried out using ASPEN HYSYS version 8.8 to assess the effects of reduction and increment of fresh catalyst makeup on the product yield while a cost analysis was done to evaluate the economic implication. The results showed that a 2% reduction of the current daily catalyst makeup gave the same yield as that of the reference value. The products also had similar qualities showing that $117,000.00/annum could be saved by a 2% reduction of the current catalyst makeup. Keywords: FCC unit; Refinery; Simulation; Catalyst; Attrition 1. Introduction Over the years, catalyst deactivation is one of the challenges of the fluid catalytic cracking (FCC) unit operation. Deactivation in heterogeneous catalysts could be physical or chemical. Whereas chemical deactivation involves the reaction of the catalytic phase of these catalysts with other compounds thereby leading to their destruction, physical deactivation such as attrition involves the physical degradation of these catalysts (Cerqueira et al., 2008). Attrition is a major concern in the FCC process and is responsible for most of the material and economic losses encountered in this unit. It occurs as a result of catalyst particle motion and inter-particle collision arising from the gas flow and bed-to-wall impact during the reaction process. As much as these collisions are necessary for the operation of fluidized-bed reactors, the consequent attrition leading to the generation of fines which pass as dust and the loss of valuable materials is a significant drawback in the operation of the FCC unit (Wu et al., 2016; Wei et al., 1977). These losses have both operational and economic implications for the running of these units. This is because the loss of these catalyst particles results in the need for addition of makeup catalyst to keep the system at a level required for optimum performance (Kramp et al., 2011; Wether and Reppenhagen, 1999). Moreover, whereas increased coarseness of the fluid bed is undesirable, a bed whose particle size distribution comprises of extremely fine particles might also not achieve the desired result. Sources of attrition include activities inside the cyclone, particle motion and collisions in the fluid bed (bubble phase) and grid jet (transport phase). Studies have also been carried out on attrition in these regions (Werther and Hartge, 2003). Wei et al. (1977) attributed reasons for catalyst losses to the possible existence of catalyst attrition