Abstract: The invention relates to a hydrocracking process and system. The gas oil feedstock and hydrogen are mixed and reacted in a hydrotreating unit. The resulting reaction effluent is sent to a first hydrogenation cracking unit and reacted by contacting a hydrogenation cracking catalyst I to obtain light fraction I rich in paraffins and heavy fraction I rich in cyclic hydrocarbons. The heavy fraction I is mixed with hydrogen and reacted in a second hydrogenation cracking unit, thereby producing heavy fraction II rich in cyclic hydrocarbons. The present invention wholly realizes the high-selective directional conversion of gas oil feedstock according to the chain structure and the ring structure and can produce chemical raw materials rich in paraffins and naphthenic speciality oil rich in cyclic hydrocarbons.

Abstract: A process includes: cutting a hydrocarbon-containing feedstock oil into a light distillate oil and a heavy distillate oil; introducing the light distillate oil and a first catalyst into a down-flow reactor to produce a stream; subjecting the stream to a gas-solid separation to produce a first reaction hydrocarbon product and a first spent catalyst; or, introducing the stream into a fluidized bed reactor, and then subjecting to a gas-solid separation to produce a second reaction hydrocarbon product and a second spent catalyst; introducing a continuous catalyst, the heavy distillate oil and a second catalyst into an up-flow reactor, and then subjecting to a gas-solid separation to produce a third reaction hydrocarbon product and a third spent catalyst; separating out lower carbon olefins and light aromatics from reaction hydrocarbon products, separating out a light olefin fraction, and returning the light olefin fraction to the fluidized bed reactor or the up-flow reactor.