New tests rate FCC catalysts for resid

A study has been made to properly assess the effects of feedstock metals on fluid catalytic cracking (FCC) catalyst properties and performance, especially activity and product selectivity in the presence of residuum material. The conversion of vacuum gas oils (VGO) to gasoline with the FCC cracking process has been practiced for many decades with minor metal contaminant problems. To avoid these problems, operators generally kept metal concentration in the feedstocks below 1 ppm by proper use of vacuum distillation. Subsequent deposition on the cracking catalyst was usually kept at levels below 1,000 ppm. Because the coke producing tendencies of these feedstocks were also low (i.e., low Conradson carbons), regenerator temperatures were also low.