ABSTRACT
Catalytic cracking is employed to convert atmospheric residue and vacuum gas oil to lighter products. Fluid catalytic cracking (FCC) is a short contact time conversion that employs a combination of thermal shock conversion and acid catalysis. Originally, cracking was accomplished thermally, but the catalytic process has almost completely replaced thermal cracking in refineries because more gasoline, having a higher octane number and fewer heavy fuel oils and light gases, is produced. The antecedence of catalytic cracking can be traced back to aluminum chloride catalyzed cracking in the 1910–1920 period. Due to the dominance of FCC as the catalytic cracking process in refineries, the subsequent discussion will deal exclusively with FCC. Metals accumulate on the FCC catalyst and lead to unwanted side reactions during operation. The feed material to the FCC unit is a combination of fresh feed and recycled feed.
