Patent ID: 7973209

Claim:
A process for catalytically cracking a heavy hydrocarbon feedstock and obtaining light olefins substantially free of carbon dioxide, 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, and a quantity of carbon dioxide; separating the hydrocarbon effluent in a hydrocarbon separation section comprising a compression section to form at least one separator liquid stream and a separator vapor stream, the at least one separator liquid stream comprising C 4 + hydrocarbons with less than about 100 ppm of carbon dioxide, the separator vapor stream comprising C 4 − hydrocarbons and at least a portion of the quantity of carbon dioxide; treating the separator vapor stream in an amine treatment section with an amine absorption solvent at treatment conditions effective to absorb a significant portion of the carbon dioxide from the separator vapor stream and to form a treated stream comprising C 4 − hydrocarbons substantially free of carbon dioxide and a first process stream comprising propylene and less than 1 wt. % of carbon dioxide; recycling said first process stream to said hydrocarbon separation section for further processing; and fractionating at least a portion of the treated stream comprising C 4 − hydrocarbons substantially free of carbon dioxide to at least form a first light olefin product stream comprising ethylene substantially free of carbon dioxide and a second light olefin products stream comprising propylene substantially free of carbon dioxide.