Abstract: Based on the Daqing vacuum gas oil’s reaction on an acid Y zeolite catalyst, hydride transfer and hydrogen transfer were distinguished as two different reaction stages during the catalytic cracking. Hydride transfer takes place at conversion intervals between 5%～10% and 60%～70%, while hydrogen transfer occurs at conversions above 60%～70%. Coke, independent of hydride transfer, is mainly produced by hydrogen transfer. The hydrogen transfer reaction on the Y zeolite catalyst mainly takes place between gasoline olefins and naphthenes.

Key words: vacuum gas oil, catalytic cracking, hydride transfer, hydrogen transfer