Abstract: Four key components of hydrogenated LCO,including tetralin,indan,decalin and 3-ethyltoluene,were used as model compounds.A small fixed fluidized bed (ACE) unit and Y zeolite catalyst was used to study the catalytic cracking performance.The results showed that the model compounds showed their unique reaction characteristics at the two conversion depths, tetralin mainly underwent hydrogen transfer reaction, and the alkylation/alkylation transfer and dehydrogen-condensation of indan were more likely to generate heavy aromatic hydrocarbons above C₉. Although decalin has high ring-opening and cracking selectivity，the selectivity of aromatic hydrocarbon products is low. The light efficiency of 3-ethyltoluene is mainly affected by isomerization reaction.The BTEX mass selectivity of tetralin,indan,decalin and 3-ethyltoluene were 22.65%,19.66%,15.70% and 34.36%,respectively.Tetralin and indan are prone to the continuous α-C-C bond fracture to form benzene;decalin is more inclined to form xylene due to the existence of two tert-carbenium ions;3-ethyltoluene has a higher molar selectivity of toluene and ethylbenzene.

Key words: hydrogenated LCO, catalytic cracking, light aromatic hydrocarbon, benzene, toluene, xylene