A process for converting naphtha, lower olefin, light aromatic hydrocarbon, and gasoline with a high octane number by combining catalytic cracking of naphtha with steam cracking of lower alkane and catalytic cracking of higher alkanes and higher olefins. The process increases the yield of product with high value and significantly decreases the yield of low value product. At the same time, the power consumption is decreased as a whole since most reactants are converted in catalytic cracking at a lower temperature.

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 pyrolysis wax comprising a naphtha/diesel fraction and heavy fraction, and char. The pyrolysis oil and wax is passed to a refinery FCC feed pretreater unit. A heavy fraction is recovered and sent to a refinery FCC unit, from which a C.sub.3 olefin/paraffin mixture fraction is recovered, which is passed to a steam cracker for ethylene production. In another embodiment, a propane fraction (C.sub.3) is recovered from a propane/propylene splitter 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 pyrolysis wax comprising a naphtha/diesel fraction and heavy fraction, and char. The pyrolysis oil and wax is passed to a refinery FCC feed pretreater unit. A heavy fraction is recovered and sent to a refinery FCC unit, from which a C.sub.3 olefin/paraffin mixture fraction is recovered, which is passed to a steam cracker for ethylene production. In another embodiment, a propane fraction (C.sub.3) is recovered from a propane/propylene splitter and passed to the steam cracker.

In accordance with one or more embodiments herein, an integrated process for upgrading a hydrocarbon oil feed stream utilizing a delayed coker, steam enhanced catalytic cracker, and an aromatics complex includes solvent deasphalting the hydrocarbon oil stream; delayed coking the heavy residual hydrocarbons; hydrotreating the delayed coker product stream and the deasphalted oil stream to form a light C.sub.5+ hydrocarbon stream and a heavy C.sub.5+ hydrocarbon stream; steam enhanced catalytically cracking the light C.sub.5+ hydrocarbon stream; steam enhanced catalytically cracking the heavy C.sub.5+ hydrocarbon stream; passing at least a portion of the light steam enhanced catalytically cracked stream, the heavy steam enhanced catalytically cracked stream, or both to a product separator to produce a olefin product stream, a naphtha product stream, and a BTX product stream; and processing the naphtha product stream in the aromatics complex to produce benzene and xylenes.

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 pyrolysis wax comprising a naphtha/diesel fraction and heavy fraction, and char. The pyrolysis oil and wax is passed to a refinery FCC feed pretreater unit. A heavy fraction is recovered and sent to a refinery FCC unit, from which a C.sub.3 olefin/paraffin mixture fraction is recovered, which is passed to a steam cracker for ethylene production. In another embodiment, a propane fraction (C.sub.3) is recovered from a propane/propylene splitter 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 pyrolysis wax comprising a naphtha/diesel fraction and heavy fraction, and char. The pyrolysis oil and wax is passed to a refinery FCC feed pretreater unit. A heavy fraction is recovered and sent to a refinery FCC unit, from which a C.sub.3 olefin/paraffin mixture fraction is recovered, which is passed to a steam cracker for ethylene production. In another embodiment, a propane fraction (C.sub.3) is recovered from a propane/propylene splitter and passed to the steam cracker.

Systems and methods for processing a plastic are disclosed. The system includes a feeding device in fluid communication with a cracking unit. A feed stream comprising a plastic is depolymerized in the feeding device at a depolymerization temperature to produce a hydrocarbonaceous wax stream. The hydrocarbonaceous wax stream is then cracked in the cracking unit. The cracking is conducted at a cracking temperature that is lower than, or the same as the depolymerization temperature.

Systems and methods for processing a plastic are disclosed. The system includes a feeding device in fluid communication with a cracking unit. A feed stream comprising a plastic is depolymerized in the feeding device at a depolymerization temperature to produce a hydrocarbonaceous wax stream. The hydrocarbonaceous wax stream is then cracked in the cracking unit. The cracking is conducted at a cracking temperature that is lower than, or the same as the depolymerization temperature.

The invention provides a process of maximizing production of chemical raw materials by gaseous phase catalytic cracking crude oil with multi-stages in milliseconds in combination with hydrogenation, comprising: a high-efficiency atomizing nozzle sprays the preheated crude oil into an upper portion of the downflow modification reaction tube, the produced oil mist is mixed with a high temperature heat carrier flowing downward from a first return controller for pyrolysis in milliseconds and then the pyrolysis products are subject to a gas-solid separation; the coked heat carrier obtained by the separation enters into a modification regeneration reactor to conduct a regeneration reaction, the obtained high temperature heat carrier returns to a top of the downflow reaction tube to participate in circulation, the regeneration gas is subject to heat exchange and then output; the high temperature oil and gas produced by the pyrolysis reaction directly flow into the millisecond cracking reactor and conduct a cracking reaction with the regenerated cracking catalyst and subject to a gas-solid separation; then the cracking catalyst to be regenerated enters the crack regeneration reactor and performs a regeneration reaction and then are subject to a gas-solid separation, the obtained high temperature crack catalyst passes through a second return controller and flows into the millisecond cracking reactor to participate the circulation reaction, the obtained flue gas is subject to heat exchange and then output; the cracked oil and gas produced by the cracking reaction enter into a fractionation tower for separation, thereby obtain the cracked gas, gasoline fraction, diesel fraction, recycle oil and oil slurry; furthermore, the diesel fraction, recycle oil and oil slurry are subject to saturation or open-ring in a hydrogenation reactor, return and mix with crude oil such that the mixture is used as a raw material.

The delayed coking method includes directing a heated secondary feedstock, which contains heated primary feedstock and recirculate, from a reaction furnace to a coking chamber. Vapor-liquid coking products formed in the coking chamber are then directed to a fractionation column, which fractionates hydrocarbon gas, gasoline, light and heavy gas oils, and bottom residues. Heavy gas oil from the fractionation column is directed to a thermal cracking furnace, the products of which are cooled by cooled light gas oil and directed to an evaporator for separation. In the evaporator, gases and light boiling products are removed by evaporation and returned to the fractionation column, and the remaining distillate cracking residue is separated and used as a component of the recirculate, along with bottom residues from the fractionation column. The resulting process produces high quality and high yield needle and anode cokes.