In service measurement of a process media distribution by using a sealed gammer-ray source (60Co) at the catalyst riser of the fluid catalytic cracking unit (FCCU) in a petroleum refinery

Gamma scans were performed on a catalyst riser of FCCU in service by using a sealed gamma-ray source 60Co and an automatic gamma scanner, specifically designed for a protection against a high heat for the purpose of an investigation the fluidized pattern of a catalyst. The internal media which was composed of the catalyst, the heavy oil, and steam was distributed homogeneously and impurities such as deposited coke were not found at the lower part of the region connected to the nozzles. However, some suspicious zones which were considered as abnormal conditions were detected between the steel grating and the nozzles. Generally the amount of media distribution at the lower part of the riser was larger than that of the upper part. From this experiment by using a gamma source, the conditions of a media distribution were identified and any abnormal areas were successfully localized.