olefin production from catalytic cracking of light fuel oil over different additives

the catalytic cracking of a fuel oil over fluid catalytic cracking (fcc) catalyst has been investigated applying different additives. catalyst mixtures consisting of a equilibrium fcc catalyst (e-cat) blended with zsm-5, mcm-41 and mordenite additives were examined at the additive levels of 25 wt.%. the catalytic performance of the matrix was studied in a fixed bed micro-activity test unit (mat) at 600 ˚c and catalyst/oil ratio of 3.6. two types of zsm-5 with different si/al ratios were utilized. results indicate that the yield of light olefins significantly increased by operating hybrid catalysts in comparison with the base e-cat. the highest olefin yield of 61.46 wt.% in the gas phase products was achieved over e-cat/zsm-5 of low si/al ratio. the maximum propylene production was observed over mcm-41, besides applying mordenite as additive showed more propylene to ethylene ratio in products. butenes were also increased by use of all additives, whereas iso-butene shows the maximum yield over all e-cat/additives.