Patent ID: 7737317

Claim:
A process for catalytically cracking a heavy hydrocarbon feedstock and obtaining selected hydrocarbon fractions, the process comprising: contacting a heavy hydrocarbon feedstock with a hydrocarbon cracking catalyst in a fluidized reactor zone to produce a hydrocarbon effluent comprising a range of hydrocarbon products including light olefins, the hydrocarbon cracking catalyst having a catalyst composition including a first component comprising a large pore molecular sieve and a second component comprising a zeolite with no greater than medium pore size, said zeolite with no greater than medium pore size comprising at least 1.0 wt. % of the catalyst composition; separating the hydrocarbon effluent in a separation system comprising a main column section and a compression section to form at least one separator liquid stream and a separator vapor stream, the main column section providing one or more cuts selected from the group consisting of gasoline, light cycle oil, heavy cycle oil and clarified oil, and the at least one separator liquid stream comprising C 4 + hydrocarbons, the separator vapor stream comprising C 4 − hydrocarbons; deethanizing at least a portion of the separator vapor stream to at least form a first deethanizer process stream comprising C 2 − hydrocarbons including a quantity of ethylene and a second deethanizer process stream comprising C 3 + hydrocarbons including a quantity of propylene; demethanizing the first deethanizer process stream to form a first demethanizer process stream comprising hydrogen and methane and a second demethanizer process stream comprising C 2 hydrocarbons including at least a portion of the quantity of ethylene; splitting the second demethanizer product stream in a C 2 hydrocarbon splitter to form a first C 2 hydrocarbon splitter process stream comprising ethylene and a second C 2 hydrocarbon splitter process stream comprising ethane; depropanizing the second deethanizer process stream to form a first depropanizer process stream comprising C 3 − hydrocarbons including a quantity of propylene and a second depropanizer process stream comprising C 4 + hydrocarbons; and treating at least a portion of the at least one separator liquid stream and at least a portion of the second depropanizer process stream in at least a single downstream processing unit.