Abstract: The effects of aging time of FCC catalyst on the distribution of reaction products, gas and gasoline composition were investigated in a small fixed fluidized bed unit with hydrotreated VGO as raw material under the conditions of a reaction temperature of 500 ℃, a water injection rate of 10%, a mass space velocity of 10h-1 and a mass ratio of catalyst to oil of 6. The results showed that the effects of catalyst aging time had a good correlation with the acid amount and specific surface area of catalyst. When the catalyst aging time exceeded 8 h, the yields of dry gas and coke were relatively low,while the total liquid yield was relatively high. When the catalyst aging time was more than 25 h, it was beneficial to achieve high propylene yield and control propane yield. The benzene content of total aromatics in gasoline was not affected by aging time. The reduction of the benzene content in gasoline product of different production schemes could be achieved by reducing the total amount of aromatics through changing catalyst aging time by adjusting the amount of cracking catalyst supplement.

Key words: catalytic cracking, hydrotreated VGO, catalyst, aging time, product distribution