Secondary Cracking of Gasoline and Diesel from Heavy Oil Catalytic Pyrolysis1

This paper investigated the secondary cracking of gasoline and diesel from the catalytic pyrolysis of Daqing atmospheric residue on catalyst CEP-1 in a fluidized bed reactor. The results show that the secondary cracking reactivity of gasoline and diesel is poor, and the yield of total light olefins is only about 10% (by mass). As reaction temperature increases, ethylene yield increases, butylene yield decreases, and propylene yield shows a maximum. The optimal reaction temperature is about 670°C for the production of light olefins. With the enhancement of catalyst-to-oil mass ratio and steam-to-oil mass ratio, the yields of light olefins increase to some extent. About 6.30% of the mass of total aromatic rings is converted by secondary cracking, indicating that aromatic hydrocarbons are not easy to undergo ring-opening reactions under the present experimental conditions.