Impact of Metal Ridging on the Fluidization Characteristics of FCC Catalyst

• Published in: Chemical engineering & technology Vol. 25; no. 10; pp. 981 - 987
• Main Authors: Whitcombe, J. M., Agranovski, I. E., Braddock, R. D.
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 08-10-2002; WILEY‐VCH Verlag; Wiley-VCH
• Subjects: Applied sciences; Attrition; Catalysts; Crude oil, natural gas and petroleum products; Energy; Exact sciences and technology; Fluidization; Fuels; Metal deposition; Processing of crude oil and oils from shales and tar sands. Processes. Equipment. Refinery and treatment units; Scanning Electron Microscopy (SEM); Oil industry; Scanning electron microscopy; Fluidity; Refining; Fluid catalytic cracking; Fluidization; Catalyst
• ISSN: 0930-7516; 1521-4125
• DOI: 10.1002/1521-4125(20021008)25:10<981::AID-CEAT981>3.0.CO;2-F

Minimum fluidization and bubbling velocities were used to compare the fluidity of FCC catalyst sourced from various refineries. It was found that fluidity characteristics of the catalyst of the same original type change after some period of use in the FCCU. Under closer examination using Scanning Electron Microscopy (SEM), large surface ridging of metal contaminates, was identified on the used catalyst. Mild bubbling attrition tests were conducted, and it was found that all of the catalyst experienced an increase in fluidity. Using total levels of iron, it was discovered that it is the quantity of metal ridging that is important and not the total levels of metals which influence fluidizing characteristics. This work provides insight into what causes changes to fluidizing characteristics inside an operation FCCU.
Fluidization is a widely used process essential to many industrial facilities including oil refineries, where Fluidized Catalytic Cracking Units (FCCU) are used extensively. FCCUs use fine zeolite based catalyst to catalytically crack long chained hydrocarbons into shorter more valuable ones. During the cracking process, coke is deposited onto the surface of the catalyst, which is then burnt off in a large fluidized bed. Maintaining optimal fluidization inside the bed is essential, allowing correct recharging of the catalyst as well as improving circulation throughout the FCCU. With the use of SEM imaging and x‐ray analysis, accumulated metal compounds were identified as forming long ridges on the surface of e‐cat particles. Although other metals are present in these ridges, it appears that iron is the primary component.