Patent ID: 7820033

Claim:
A process for increasing ethylene yield in a cracked hydrocarbon, comprising: heating a hydrocarbon feed stream comprising at least 90% by weight of one or more C 4 -C 10 hydrocarbons to provide an effluent stream comprising at least 5% by weight propylene; selectively separating the effluent stream to provide a first stream comprising heavy naphtha, light cycle oil, slurry oil, or any combination thereof and a second stream comprising one or more C 1 -C 10 hydrocarbons; treating the second stream to remove oxygenates, acid gases, water, or any combination thereof to provide a third stream comprising the one or more C 1 -C 10 hydrocarbons; selectively separating the third stream to provide a product stream comprising at least 30% by weight propylene and a tail gas stream comprising at least 30% by weight methane; recycling at least a portion of the tail gas stream to the hydrocarbon feed stream; and recycling at least a portion of the product stream to the hydrocarbon feed stream to increase ethylene yield in the effluent stream.