Catalyst Attrition Research Articles

Properties analysis of catalyst particles during stripper distributor fault in industrial fluid catalytic cracking unit

Particle attrition is prevalent in fluid catalytic cracking (FCC) process, and severe particle attrition threatens the steady operation of FCC units. In this study, the processes of attrition and dealing in industrial FCC unit were investigated, and the relationship between particle physical properties and fault source was analyzed. The results showed that the most frequent particle sizes of the attrited equilibrium catalyst and the spent catalyst were 48.85 μm and 55.21 μm, respectively. The replacement of attrited catalyst by equilibrium catalyst with higher mechanical strength could alleviate the catalyst attrition problem, and the most frequent particle size of the catalyst remained at 75.81 μm after experiencing attrition. When the replacement rate reached 66.83 %, catalyst loss was reduced and the stability of FCC unit operation was significantly improved. This study would contribute to a deeper understanding of the particle abrasion and fragmentation behavior in different environments in industrial FCC units.

Performance assessment of novel catalytic spouted-bed vapor jet flow heat exchanger in amine-based carbon capture process

This study introduced a spouted bed and jet flow catalytic heat exchanger (SBJ-EX). This novel non-agitated technology can potentially integrate with a conventional desorption column to enhance heat transfer and CO2 desorption performance in amine-based post-combustion carbon capture systems. As its first research in the carbon capture field, this work experimentally evaluated key factors including overall heat transfer coefficient, logarithmic mean temperature difference, temperature distribution along the reactor, and cyclic loading under varied parameters such as inlet temperature of the heating oil, inlet solvent temperature, rich CO2 loadings, and mass of catalysts to simulate real-world operating conditions using benchmark MEA solvent and solid acid catalyst HZSM-5. Compared to conventional plate heat exchangers, the SBJ-EX demonstrated over a 70 % enhancement in heat transfer performance due to its effective overall heat transfer coefficient. It also exhibited impressive CO2 desorption performance even at lower temperatures with sufficient catalysts. Unlike agitated-type heat exchangers, the SBJ-EX could minimize catalyst attrition and offer more excellent stability. In contrast to fixed-bed catalyst desorbed columns, this equipment offered a more compact design for quicker and simpler catalyst replacement to reduce downtime for operators significantly. The SBJ-EX can also function as an optional backup or add-on unit to provide operators with flexibility. This work further discussed advantages and challenges of the SBJ-EX operation. This work enriched the future research outlook for this technology, and contributed a commercially viable approach to catalysts in carbon capture processes.

Advances in design of internals: Applications in conventional and process intensification units

Internals within reactors play an important role in the chemical industry, and numerous studies focus on their investigation and development. This review discusses the application of internals in both conventional and Process Intensification (PI) units, including stirred tanks, fluidized beds, bubble columns, tubular vessels, trickle beds, spinning disks, rotating packed beds, rotating fluidized beds, and microreactors. It emphasizes enhancing mass and heat transfer through internals such as baffles, packing, heat exchange elements, and wall modifications. Recurring themes include phase distribution, interfacial area, slip velocities, heat transfer, and pressure drop. While internals offer benefits, challenges such as fouling and catalyst attrition are acknowledged, yet often under-quantified. Practical aspects, including manufacturing and safety, are often overlooked. The review highlights the urgent need for comprehensive evaluations, incorporating detailed Computational Fluid Dynamics (CFD) simulations and experimental studies. Based on previous research, this work aims to provide insights into innovative reactor designs that ultimately lead to optimal efficiency and energy balance in chemical processes.

Characterization of Equilibrium Catalysts from the Fluid Catalytic Cracking Process of Atmospheric Residue

In the FCC conversion of heavy petroleum fractions as atmospheric residues, the main challenge for refiners to achieve the quantity and quality of various commercial products depends essentially on the catalyst used in the process. A deep characterization of the catalyst at different steps of the process (fresh, regenerated, and spent catalyst) was investigated to study the catalyst’s behavior including the physicochemical evolution, the deactivation factor, and kinetic–thermodynamic parameters. All samples were characterized using various spectroscopy methods such as N2 adsorption–desorption, UV-visible spectroscopy, Raman spectroscopy, LECO carbon analysis, scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray fluorescence (XRF), nuclear magnetic resonance spectroscopy (NMR13C) analysis, and thermogravimetric analysis. The results of the N2 adsorption–desorption, UV-vis, Raman, LECO carbon, and SEM imaging showed that the main causes of catalyst deactivation and coking were the deposition of carbon species that covered the active sites and clogged the pores, and the attrition factor due to thermal conditions and poisonous metals. The XRD and XRF results showed the catalyst’s physicochemical evolution during the process and the different interlinks between catalyst and feedstock (Nickel, Vanadium, Sulfur, and Iron) elements which should be responsible for the coking and catalyst attrition factor. It has been found that, in addition to the temperature, the residence time of the catalyst in the process also influences catalyst structure transformation. NMR13C analysis revealed that polyaromatic hydrocarbon is the main component in the deposited coke of the spent catalyst. The pyridine-FTIR indicates that the catalyst thermal treatment has an influence on its Brønsted and Lewis acid sites and the distribution of the products. Thermogravimetric analysis showed that the order of catalyst mass loss was fresh > regenerated > spent catalyst due to the progressive losses of the hydroxyl bonds (OH) and the structure change along the catalyst thermal treatment. Moreover, the kinetic and thermodynamic parameters showed that all zones are non-spontaneous endothermic reactions.

Migration and emission characteristics of metal pollutants in fluid catalytic cracking (FCC) process

Fluid catalytic cracking (FCC) is the core unit for heavy oil conversion in refineries. In the FCC process, the metal contaminants from the feedstock are deposited on the catalysts, causing catalyst deactivation and metal particulate matter (PM) emission. However, the migration and emission characteristics of metal pollutants in FCC units are still unclear. Here, the stack tests of three FCC units were carried out to monitor metal PM emissions, and the metal contents of the feedstock oil and spent catalyst were detected. For the metal migration from the feedstock to the catalysts, Ni, Fe, and V have high concentrations and migration rates while other metals perform much lower. The metal distribution on the spent catalysts profoundly determines the metal mobility to the flue gas and the regeneration process affects the catalyst attrition, leading to metal PM emissions discrepancy. The migration rate and emission concentration of V in the deeper layers of the catalysts are much lower than those of Ni at the particle’s exterior. Finally, the stack data was used to calculate the emission factors and ratio factors of the metal PM. This work is expected to advance metal migration cognition and metal pollutants emissions estimation in FCC units.

A modelling approach to investigate the performance of slurry bubble column reactors implementing Fischer–Tropsch synthesis

AbstractA reliable estimation of the reactor performance is a crucial aspect of slurry bubble column reactor design. Hydrodynamics, mass transfer, and reaction rate are the main parameters influencing the overall performance. A new hydrodynamic model was adopted in this study to properly predict the effect of solids loading, particle size, pressure, and temperature on the gas holdup, bubble size distribution, and mass transfer coefficient. The reactor was divided into small cells with individual hydrodynamic parameters. The results were compared with the experimental data and showed that the model can acceptably predict the hydrodynamic and mass transfer parameters in various process situations. A parametric study was accomplished to understand the effect of catalyst loading, superficial gas velocity, H2/CO ratio, L/D ratio, pressure, temperature, and catalyst attrition on the conversion rate, catalyst productivity, and space–time yield. A cobalt/silica catalyst was adopted in this study. Based on the obtained results, the syngas conversion increases by catalyst loading, L/D, and temperature, while it decreases by Ug and pressure. The H2/CO ratio results in a maximum conversion somewhere between 2 and 2.5. Three different scenarios were determined to study the effect of catalyst attrition on the reactor performance. The results show that the attrition decreases the syngas conversion due to the decrease in the catalyst size and the catalyst loss. Also, the performance remains constant if a sufficient amount of fresh catalyst is added to the system continuously.

Catalyst deactivation and the effect of catalyst makeup on the FCC unit

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.

Sonochemical Synthesis of Silica-Supported Iron Oxide Nanostructures and Their Application as Catalysts in Fischer–Tropsch Synthesis

The emphasis on climate change requires processes to be more efficient to minimize CO2 emissions, and nanostructured materials as catalysts could play a crucial role due to their high surface area per unit volume. Herein, we report the synthesis of silica microspheres (450–600 nm) using a modified Stober process, on which iron oxide clusters were deposited by sonolysis of iron pentacarbonyl to yield a nanostructured iron material (Si-Fe). A suite of spectroscopic techniques was used to characterize the synthesized materials. The BET surface area of freshly prepared Stober silica was 8.00 m2/g, and the Si-Fe material was 24.0 m2/g. Iron is commercially used as a Fischer–Tropsch (F–T) catalyst due to its low cost. However, catalyst attrition causes catalyst loss and lower product quality. In this study, the synthesized Si-Fe materials were evaluated for F–T synthesis to address these challenges. For comparison, two commercial materials, UCI (silica-supported micron-sized iron oxide) and BASF (unsupported nanosized iron oxide), were also evaluated. All three materials were first activated by pretreatment with either CO or synthesis gas (a mixture of CO and H2) for 24 h, then evaluated for quick screening in batch mode for F–T synthesis in a Parr batch reactor at three temperatures: 493 K, 513 K, and 533 K. The F–T data at 513 K showed that the CO-pretreated Si-Fe catalyst demonstrated lower CO2 (<0.5%), lower CH4 (<0.5%), and higher (>58%) C8–C20 selectivity (mol% C) to hydrocarbons, surpassing both reference catalysts. The temperature dependence data for Si-Fe: 17.4%, 58.3%, and 54.9% at 493 K, 513 K, and 533 K, respectively, showed that the hydrocarbon yield maximized at 513 K. The surface area increased to 27.9 m2/g for the CO-reduced Si-Fe catalyst after the F–T reaction at 513 K. The morphology and structural change of catalysts, before and after the F–T runs, were imaged. Of all the catalysts evaluated, the SEM–EDS data analysis showed the least carbon deposition on the CO-treated Si-Fe catalyst after the F–T reaction at 513 K and minimized CO2, a greenhouse gas. This could pave the way for selecting nanomaterials as F–T catalysts that effectively operate at lower temperatures and produce negligible CO2 by minimizing water-gas-shift (WGS) activity.

Optimization of annular distributor for industrial riser reactor with weakened catalyst attrition

AbstractCatalyst attrition and nonuniform gas–solid distribution were observed in an oil refining and chemical enterprise with straight pipe as C4 mixture gas feed zone, which induced unfavored catalytic reaction and unqualified products. In this work, a fluidized attrition experiment circulating system consisting of a riser reactor at a bench scale was constructed to implement fluidized attrition experiment. Four annular pipe distributors were designed as C4 mixture gas feed zones and compared with traditional straight pipe in order to gain insight into the catalyst attrition condition in the riser reactor. At the same time, computational fluid dynamic technique was applied to investigate the gas–solid mixing situation in the riser reactor with five different C4 mixture gas feed zones. Structure four of annular distributor with nine nozzles distributed as well as an inclination of 30° displayed a catalyst attrition of 5.7% in 12 h of fluidized circulation and possessed the best gas–solid mixing condition as well as the highest catalyst volume fraction distribution in the main catalyst reaction space. Therefore, structure four was selected as C4 mixture gas feed zone for industrial riser reactor. Flow behavior in the industrial riser reactor with the optimized C4 annular distributor was further investigated via numerical simulation and compared with traditional straight pipe as C4 mixture gas feed zone so as to provide reference for the optimization of industrial riser reactor. When annular distributor was applied, propylene yield enhanced to 19.86%, and meanwhile, enhancement of catalyst particle with size smaller than 40 μm obviously decreased in comparison with traditional riser reactor.

Study on attrition of spherical-shaped Mo/HZSM-5 catalyst for methane dehydro-aromatization in a gas–solid fluidized bed

As a potential methane efficient conversion process, non-oxidative aromatization of methane in fluidized bed requires a catalyst with good attrition resistance, especially in the states of high temperature, long-time rapid movement and chemical reaction. Existing evaluation methods for attrition resistance, such as ASTM D5757 and Jet Cup test, are targeted for fresh catalysts at ambient temperature, which cannot well reflect the real process. In this study, spherical-shaped Mo/HZSM-5 catalyst prepared by dipping and spray drying was placed in a self-made apparatus for attrition testing, in which the catalyst attrition under different system temperatures, running time and process factors was investigated with percent mass loss (PML), particle size-mass distribution (PSMD) and scanning electron microscope (SEM). Carbon deposition on the catalyst before and after activation, aromatization and regeneration was analyzed by thermogravimetry (TG), and the attrited catalysts were evaluated for methane dehydro-aromatization (MDA). The results show that the surface abrasion and body breakage of catalyst particles occur continuously, with the increase of system temperature and running time, and make the PML rise gradually. The process factors of activation, aromatization and regeneration can cause the catalyst attrition and carbon deposits, which broaden the PSMD in varying degrees, and the carbon-substances on catalysts greatly improve their attrition resistance at high temperature. Catalyst attrition has a certain influence on its catalytic performance, and the main reasons point to particle breakage and fine powder escape.

Attrition-resistant Ni[sbnd]Mg/SiO2[sbnd]Al2O3 catalysts with different silica sources for fluidized bed syngas methanation

Attrition-resistant NiMg/SiO2Al2O3 catalysts for fluidized bed syngas methanation were prepared by combining co-precipitation and spray granulation using different silica sources including acidic silica sol (SS), sodium silicate (NS) and tetraethyl orthosilicate (TEOS). Air-jet attrition tests showed that the attrition strength of the resulting catalysts followed an order of C-10TEOS > C-33SS > C-10NS > C-10SS, where C-10TEOS, as an example, refers to the catalyst with 10 wt.% silica using TEOS as its silica source. Characterizations show that the porosity and skeletal structure have strong correlation with catalyst attrition strength. Simultaneous hydrolysis of TEOS and co-precipitation caused C-10TEOS to have dense and continuous skeletal structure to have the high strength of its NiMg/SiO2Al2O3 precursor particles and thus the improved attrition resistance of sprayed catalyst. Silica sol filled in the voids among precursor particles resulted in a compact framework in C-33SS but its NiMg/Al2O3 precursor had weak attrition resistance. Atmospheric syngas methanation over these catalysts at an SV of 600 NL g−1 h−1 in a fixed bed reactor clarified an activity order of C-10TEOS > C-10NS ≈ C-33SS. The TEOS also enabled highly dispersed metallic Ni and many surface active sites to facilitate the methanation activity and stability of this catalyst.

Attrition of methanol to olefins catalyst in jet cup

Attrition of catalyst in a fluidized bed reactor is an inevitable issue especially in a commercial unit. Methanol to olefins (MTO) is becoming one of the main stream technologies for light olefins production. The attrition of MTO catalyst, however, received little attention. This study is focused on the attrition behavior of MTO catalyst in jet cup at high temperature. The influence of test time, inlet gas velocity, and temperature on MTO catalyst attrition was studied. It is found that the Gwyn formulation can well represent the relation between attrition index and test time. Our results show that jet cup can retrieve results quantitatively comparable to high velocity gas jets method while significantly shortening test time. It is also found that the inlet gas velocity has considerable influence on the MTO catalyst attrition, and the relation between inlet gas velocities and attrition index can be described by a power index of 3.7. Similar to high velocity gas jets experiments the attrition index manifests a maximum with the increase of temperature. But the temperature corresponding to the maximum attrition index shifts from 300°C in high velocity jets tests to 100°C in jet cup experiments. An analysis based on SEM pictures indicates that the transition of attrition mechanism is responsible for this shift. An empirical correlation has been presented for MTO catalyst attrition in jet cup, which shows good agreement with experimental data for inlet gas velocity from 88 to 158m/s, and temperature from 100 to 500°C.

Effect of H2O2 injection patterns on catalyst bed characteristics

The decomposition process of hydrogen peroxide can be applied to a bipropellant thruster, as well as to monopropellant thruster. To provide a framework for the optimal design of the injector and catalyst bed depending on a type of thruster, this research scrutinizes the effect of injection patterns of the propellant on the performance of the catalyst bed. A showerhead injector and impinging jet injector were tested with a 50 N monopropellant thruster. Manganese oxide/γ-alumina catalyst and manganese oxide/lanthanum-doped alumina catalyst were prepared and tested. The showerhead injector provided a fast response time, suitable for pulse mode operation. The impinging jet injector mitigated the performance instability and catalyst attrition that is favorable for large scale bipropellant thrusters. The design of a dual catalyst bed was conceptually proposed based on the data obtained from firing tests.

Moving from discovery to real applications for your catalyst

We discuss the importance of operating conditions and feed gas composition in evaluating any catalyst. Test conditions are often simplified in early catalyst evaluations, but ultimately catalysts need to be evaluated close to the anticipated process conditions if one wants to make generalizations about performance with regard to an anticipated product in the marketplace; the sooner the better. This will allow others to focus on the crucial steps that one has to take to apply a new discovery to a new or existing product. We examine several different test parameters that can significantly impact a number of different reactions. One focus is on testing catalysts early during the discovery/optimization stage under conditions which anticipate major operational hurdles down the road to eventual development and onto commercialization. In particular we discuss the importance of realistic feed-gas compositions, extreme operating conditions, understanding duty cycles, in test protocols, carbon formation, catalyst attrition, wet process feeds, transient exposure to contaminants in the feed, the need to understand the impact of pressure, and catalyst morphology. These catalyst features are applied to a variety of reactions including FCC, water gas shift, steam methane reforming, auto exhaust cleanup, ozone removal in aircraft, and refinery hydrogen production. A few extended examples are also provided using prior references that describe the conversion of lab discoveries to established commercial processes.

Particle size effect on the catalyst attrition in a lab‐scale fluidized bed

Catalysts readily suffer from particle attrition in fluidized beds. In this article, a commercial fluid catalytic cracking catalyst was sieved into several particle‐size intervals to investigate the size effect on particle attrition. It is shown that an exponential decay equation presents a suitable description of attrition and that catalyst attrition is dependent on particle size. Steady‐state specific attrition rate decreases with increasing particle size; however, initial specific attrition rate and decay time parameter change irregularly. For comparison of attrition resistances, a long attrition test is required to reach steady‐state attrition, and the steady‐state specific attrition rate is recommended. It is seen that the smallest particle‐size interval is the most seriously attrited, while the two largest particle‐size intervals are the most attrition‐resistant. Furthermore, weak interactions appear among attrition behaviors of different intervals, and a linear combination method is effective to combine all interval samples to predict the attrition of the original full‐sized sample. © 2016 American Institute of Chemical Engineers AIChE J, 63: 914–920, 2017

Comparative study of attrition measurements of commercial FCC catalysts by ASTM fluidized bed and jet cup test methods

Catalyst loss due to fines generation by attrition is a major problem in refinery fluid catalytic cracking (FCC) units as it impacts inventory loss. Attrition resistance of catalyst is one of the critical parameter in catalyst selection for a FCC unit. ASTM D5757 fluidized bed attrition test is the most commonly used attrition resistance test method to rank FCC catalysts and additives. In the present study, catalyst attrition tests were performed for FCC catalysts using an ASTM fluidized bed, cylindrical jet cup and conical jet cup. Performance ranking shows that attrition index obtained by these tests vary, but the order of ranking remains unchanged for ASTM fluidized bed and conical jet cup test methods as compared to cylindrical jet cup test. The investigation conducted here shows that morphology of attrited fresh FCC catalyst using conical jet cup was found to be similar to plant equilibrium catalyst and also takes less attrition time relative to ASTM fluidized bed.

Influence of Temperature on Fluidized‐Bed Catalyst Attrition Behavior

AbstractParticle attrition is a prevalent problem in fluidized beds due to continuous moving of catalyst particles. It is always operated at high temperature either for lab‐ or industrial‐scale fluidized beds. The influence of temperature on the attrition behavior of commercial methanol‐to‐olefins (MTO) and fluid catalytic cracking (FCC) catalysts is analyzed in a three‐orifice lab‐scale fluidized bed device from room temperature to 600 °C. The two catalysts are found to be alike in attrition mode. Both change from a combination of abrasion and fragmentation to main abrasion with increasing temperature, but differ greatly in the variation of attrition index with temperature which may be attributed to the difference of material and particle properties. An empirical correlation of attrition index to attrition temperature for all test samples is proposed.

Catalyst attrition in an ASTM fluidized bed

Catalyst attrition is a major issue for the reliable and efficient performance of a fluidized-bed reactor. In this study, attrition behavior of a commercial FCC catalyst is examined in a laboratory-scale ASTM fluidized bed. An attrition rate model that combines the jet attrition and bubble-induced attrition is derived and confirmed to represent the measured total attrition rate versus the superficial gas velocity. The model parameters systematically vary with time, since the properties of the attrited particles change progressively. It is also shown that the minimum bubble attrition velocity is far larger than the minimum fluidizing velocity because energy is required to produce attrition. Furthermore, jet and bubble attritions are separated and their contributions are discussed. The contribution of jet attrition increases rapidly with increasing the gas velocity, and the fast increase in the jet attrition rate is the major cause of the increasingly serious catalyst attrition with increasing the gas velocity. It is also seen that regression analysis is an effective tool to the separation of attrition sources.

Attrition of catalyst particles in a laboratory-scale fluidized-bed reactor

Attrition of fluid catalytic cracking catalysts is investigated in a laboratory-scale fluidized bed. It is shown that the catalyst attrition arises from a mixed mechanism of particle fragmentation and surface abrasion. The measured conventional attrition rate always decreases with time, even for a long-time attrition; therefore, a relative attrition rate is suggested. Experiments indicate that after a nonsteady-state attrition where the measured relative attrition rate decreases with time, the attrition gets into a steady state and the measured relative attrition rate tends to a constant value. Furthermore, the time-dependence of particle attrition is discussed. It is seen that the widely-used Gwyn equation cannot model the catalyst attrition accurately. Alternatively, an exponential decay attrition model is proposed and confirmed to describe the time-dependent attrition behavior. It is found that the model parameters have definite meanings and are strongly related to the particle properties, fluidization conditions and fluidized bed structure.

The Selection of Fluid Catalytic Cracking Catalysts and Additives: The Significance of Attrition Studies

Fluid catalytic cracking (FCC) is an important secondary conversion process in refinery that converts heavier gas oils and residues to valuable petroleum products. In the present and future crude oil availability scenario demand for FCC process that increases the refinery margins is growing. Continuous attempts are being made to improve FCC margin through process optimization, selection and use of improved catalysts and additives as well as hardware modifications. Refiners often face challenging task of judiciously selecting and switching to improved catalysts and additives for maximizing profits without violating hardware constraints. It is very difficult to select catalyst or additives based on vendor's claims and testing the catalyst directly in the plant is also risky business. It is important to match the plant performance closely to understand unit constraints and exploit the new catalyst capabilities to full extent. Detailed study with respect to catalyst deactivation, microactivity studies, complete characterization, and prediction of performance on the commercial scale, as well as economic evaluation, are key steps in catalyst or additive selection. Catalyst attrition is key issue now days due to heavy losses observed in the plant and frequent shut downs of the CO boiler units. In riser and regenerator reactor of FCC process, catalyst undergoes attrition due to various reasons such as inherent characteristics of catalyst/additive or due to process environment. Poor attrition of either catalyst/additive result into catalyst loss, fouling, and plugging of down stream units. In this communication the attrition behavior of different catalysts and additives and combined effect of base fluid catalytic cracking catalyst along with different additives in various proportions have been evaluated using an ASTM method in laboratory. Attrition behavior of different FCC additives such as CO combustion promoter, Octane and LPG booster and gasoline sulfur reduction additives were measured in isolation as well as by mixing with base catalyst in different proportion. Certain when studied alone exhibited higher attrition when compared with others. It is observed that even though absolute attrition strength of certain additives such as gasoline sulfur is poor, when used along with base catalyst in desired proportion the loss due to attrition was minimized. This study in combination with VGO cracking activity results helps to select suitable catalyst/additive for enhancing FCC process profits.