Abstract: The study on catalytic cracking performance of FCC top reflux was conducted on a fixed fluidized bed reactor (FFB) with MLC-500 catalyst under the conditions of a weight hourly space velocity of 5h-1, a catalyst-to-oil mass ratio of 8 and a reaction temperature range of 460-540℃. Results show that 17.41% of FCC top reflux which is in diesel distillation range is cracked into gasoline fraction. Thus FCC gasoline yield can be improved. Besides, the contents of high octane number components, aromatics and C4 hydrocarbons in liquid products are increased. The aromatics in the product can be more than 50%. More than 75% aromatic hydrocarbons in the product come from alkyl-benzene cracking of FCC top reflux. Optimal reaction models for each component of hydrocarbons in FCC top reflux were also proposed.

Key words: FCC, top reflux, gasoline, octane number