Provided in one embodiment is a continuous process for converting waste plastic into recycle for polyethylene polymerization. The process comprises selecting waste plastics containing polyethylene and/or polypropylene, and passing the waste plastics through a pyrolysis reactor to thermally crack at least a portion of the polyolefin waste and produce a pyrolyzed effluent. The pyrolyzed effluent is separated into offgas, a pyrolysis oil and optionally wax comprising a naphtha/diesel and heavy fraction, and char. The pyrolysis oil and wax is passed to a refinery FCC unit from which a liquid petroleum gas C.sub.3-C.sub.5 olefin/paraffin mixture fraction is recovered. The liquid petroleum gas C.sub.3-C.sub.5 olefin/paraffin mixture fraction is passed to a refinery alkylation unit, with a propane and butane fraction recovered from the alkylation unit. The propane and butane fraction is then passed to a steam cracker for ethylene production. In another embodiment, a naphtha fraction (C.sub.5-C.sub.8) is recovered from the alkylation unit and passed to the steam cracker. In another embodiment, a propane/propylene fraction (C.sub.3-C.sub.3.sup.=) is recovered from the FCC and passed to the steam cracker.

Provided in one embodiment is a continuous process for converting waste plastic into recycle for polyethylene polymerization. The process comprises selecting waste plastics containing polyethylene and/or polypropylene, and passing the waste plastics through a pyrolysis reactor to thermally crack at least a portion of the polyolefin waste and produce a pyrolyzed effluent. The pyrolyzed effluent is separated into offgas, a pyrolysis oil and optionally wax comprising a naphtha/diesel and heavy fraction, and char. The pyrolysis oil and wax is passed to a refinery FCC unit from which a liquid petroleum gas C.sub.3-C.sub.5 olefin/paraffin mixture fraction is recovered. The liquid petroleum gas C.sub.3-C.sub.5 olefin/paraffin mixture fraction is passed to a refinery alkylation unit, with a propane and butane fraction recovered from the alkylation unit. The propane and butane fraction is then passed to a steam cracker for ethylene production. In another embodiment, a naphtha fraction (C.sub.5-C.sub.8) is recovered from the alkylation unit and passed to the steam cracker. In another embodiment, a propane/propylene fraction (C.sub.3-C.sub.3.sup.=) is recovered from the FCC and passed to the steam cracker.

Provided is a continuous process for converting waste plastic into recycle for polyethylene polymerization. In one embodiment, the process comprises selecting waste plastics containing polyethylene and/or polypropylene and passing the waste plastics through a pyrolysis reactor to thermally crack at least a portion of the polyolefin waste and produce a pyrolyzed effluent. The pyrolyzed effluent is separated into offgas, a naphtha/diesel fraction, a heavy fraction, and char. The naphtha/diesel fraction is passed to a crude unit distillation column in a refinery where a straight run naphtha (C.sub.5-C.sub.8) fraction or a propane/butane (C.sub.3-C.sub.4) fraction is recovered. The straight run naphtha fraction (C.sub.5-C.sub.8) or the propane/butane (C.sub.3-C.sub.4) fraction is passed to a steam cracker for ethylene production. The heavy fraction from the pyrolysis unit can also be passed to an isomerization dewaxing unit to produce a base oil.

Provided is a continuous process for converting waste plastic into recycle for polyethylene polymerization. In one embodiment, the process comprises selecting waste plastics containing polyethylene and/or polypropylene and passing the waste plastics through a pyrolysis reactor to thermally crack at least a portion of the polyolefin waste and produce a pyrolyzed effluent. The pyrolyzed effluent is separated into offgas, a naphtha/diesel fraction, a heavy fraction, and char. The naphtha/diesel fraction is passed to a crude unit distillation column in a refinery where a straight run naphtha (C.sub.5-C.sub.8) fraction or a propane/butane (C.sub.3-C.sub.4) fraction is recovered. The straight run naphtha fraction (C.sub.5-C.sub.8) or the propane/butane (C.sub.3-C.sub.4) fraction is passed to a steam cracker for ethylene production. The heavy fraction from the pyrolysis unit can also be passed to an isomerization dewaxing unit to produce a base oil.

Devices for generating a desired gas or mixture of gases by thermally decomposing a polymer, and methods of making and using such devices, are provided. The resulting gas or mixture of gases, or a fraction thereof, can be used for any suitable purpose, including but not limited to use as an inflating or lifting gas. The devices and methods of the disclosure provide greater mass and volumetric efficiency for gas generation and storage relative to conventional gas generation solutions and are safer and simpler than compressed gas cylinders or liquefied gas storage.

Devices for generating a desired gas or mixture of gases by thermally decomposing a polymer, and methods of making and using such devices, are provided. The resulting gas or mixture of gases, or a fraction thereof, can be used for any suitable purpose, including but not limited to use as an inflating or lifting gas. The devices and methods of the disclosure provide greater mass and volumetric efficiency for gas generation and storage relative to conventional gas generation solutions and are safer and simpler than compressed gas cylinders or liquefied gas storage.

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.

According to one or more embodiments presently disclosed, a method of catalytically converting polystyrene may include contacting polystyrene with a catalyst to form a product comprising ethylbenzene. The catalyst may include oxidized iron, oxidized cobalt, and oxidized copper. The catalyst may further include a mesoporous support material with pores having an average pore diameter of from 2 nm to 50 nm.

According to one or more embodiments presently disclosed, a method of catalytically converting polystyrene may include contacting polystyrene with a catalyst to form a product comprising ethylbenzene. The catalyst may include oxidized iron, oxidized cobalt, and oxidized copper. The catalyst may further include a mesoporous support material with pores having an average pore diameter of from 2 nm to 50 nm.

Systems and methods for recycling waste plastics are provided, including a system for recovering styrene monomer from waste polystyrene. The system includes a mixing, heating and compacting apparatus to receive a supply of waste polystyrene and to output a densified polystyrene containing melt; a pyrolysis reactor configured to receive the densified polystyrene containing melt and a supply of recycled oligomers, pyrolyze the densified polystyrene containing melt and the recycled oligomers, and output a hydrocarbon gas stream and a solids residue stream; a quenching apparatus configured to receive the hydrocarbon gas stream output from the pyrolysis reactor and condense out oligomers for routing upstream to the pyrolysis reactor to be combined as the supply of recycled oligomers with the densified polystyrene containing melt, and to discharge an altered hydrocarbon gas stream for further processing; and a condenser configured to receive the altered hydrocarbon gas stream from the quenching apparatus and condense out styrene to form a styrene monomer oil product.