NOVELTY - The integrated system comprises a fluidized reactor zone, a zone for separating the effluent stream into separator liquid stream comprising propane and propylene and a separator vapor stream, a treatment zone to remove impurities from the separator liquid stream to provide a combined propane/propylene stream, a process line feeding the combined propane/propylene stream to an alkylation reactor of an alkylation zone for reacting the propylene in the combined propane/propylene stream with benzene to form cumene, and a stripper.    USE - The integrated system is useful for catalytically cracking a hydrocarbon feedstock, obtaining selected hydrocarbon fractions including a combined propane/propylene stream and reacting the propylene of the combined propane/propylene stream with benzene to produce a cumene product stream.    ADVANTAGE - The integrated system ensures energy efficient and economic catalytic cracking of the hydrocarbon feedstock thus producing larger yield of cumene product stream with improved quality.    DETAILED DESCRIPTION - The integrated system comprises a fluidized reactor zone, a zone for separating the effluent stream into separator liquid stream comprising propane and propylene and a separator vapor stream, a treatment zone to remove impurities from the separator liquid stream to provide a combined propane/propylene stream, a process line feeding the combined propane/propylene stream to an alkylation reactor of an alkylation zone for reacting the propylene in the combined propane/propylene stream with benzene to form cumene, a stripper for stripping C2- hydrocarbon materials from the separator liquid stream to form a C3+ process stream free of C2- hydrocarbons, a heat exchanger for transferring heat from the alkylation reactor to the stripper, an amine treatment zone for removing hydrogen sulfide from the combined propane/propylene stream, an extraction zone for catalytically oxidizing and removing mercaptans from the combined propane/propylene stream, a C3/C4 splitter to remove C4+ hydrocarbons from the combined propane/propylene stream, a dryer, a carbonyl sulfide (COS) treater, an arsine treater, and a phosphine treater for removing contaminants from the combined propane/propylene stream upstream of the alkylation zone. The hydrocarbon feedstock contacts a catalyst to produce an effluent stream including propane and propylene. The C3+ process stream is treated in the treatment zone to produce the combined propane/propylene stream.    DESCRIPTION OF DRAWING(S) - The diagram shows a schematic view of a system for catalytically cracking a heavy hydrocarbon feedstock and obtaining selected hydrocarbon fractions including light olefins via an absorption-based product recovery.    Main column section (22)    Compression section (90)    Discharge vessel (94)    Dryer section (106)    Conventional pump. (125)