US Patent 10927315 Maximizing high-value chemicals from mixed plastic using different steam-cracker configurations

A process for producing olefins and aromatics comprising converting plastics to a hydrocarbon product comprising a gas phase and a liquid phase in a pyrolysis unit; separating the hydrocarbon product into a hydrocarbon gas stream comprising the gas phase and a hydrocarbon liquid stream comprising the liquid phase; feeding the hydrocarbon gas stream to a gas steam cracker to produce a gas steam cracker product comprising olefins, wherein an olefins amount in the gas steam cracker product is greater than in the hydrocarbon gas stream; separating the hydrocarbon liquid stream into a first fraction (b.p.<300° C.) and a second fraction (b.p>300° C.); feeding the first fraction to a liquid steam cracker to produce a liquid steam cracker product comprising olefins and aromatics, wherein an olefins amount in the liquid steam cracker product is greater than in the first fraction; and recycling the second fraction to the pyrolysis unit.