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 is passed to a refinery FCC unit from which a liquid petroleum gas C.sub.3 olefin/paraffin mixture fraction is recovered, as well as a C.sub.4 olefin/paraffin mixture fraction. The liquid petroleum gas C.sub.3 olefin/paraffin mixture fraction is passed to a steam cracker for ethylene production. The C.sub.4 olefin/paraffin mixture fraction is passed to a refinery alkylation unit, from which a n-butane and naphtha feed for a stream cracker to produce ethylene is recovered.

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.

A method for producing alkene gases from a cracked product effluent, the method comprising the steps of introducing the cracked product effluent to a fractionator unit, separating the cracked product effluent in the fractionator to produce a cracked light stream and a cracked residue stream, wherein the cracked light stream comprises the alkene gases selected from the group consisting of ethylene, propylene, butylene, and combinations of the same, mixing the cracked residue stream and the heavy feed in the heavy mixer to produce a combined supercritical process feed, and upgrading the combined supercritical process feed in the supercritical water process to produce a supercritical water process (SWP)-treated light product and a SWP-treated heavy product, wherein the SWP-treated heavy product comprises reduced amounts of olefins and asphaltenes relative to the cracked residue stream such that the SWP-treated heavy product exhibits increased stability relative to the cracked residue stream.

Processes and systems are disclosed for improving the yield from reforming processes. Aromatic complex bottoms, or a heavy fraction thereof, are subjected to catalytic conversion to produce additional gasoline and higher-quality aromatic compounds.

Provided is a continuous process for converting waste plastic into a feedstock for polyethylene polymerization. The process comprises selecting waste plastics containing polyethylene and/or polypropylene, and then 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 then separated into offgas, a pyrolysis oil comprising a naphtha/diesel/heavy fraction, and char. The pyrolysis oil is passed to a crude unit in a refinery from which a naphtha fraction (C.sub.5-C.sub.8), or a propane and butane (C.sub.3-C.sub.4) fraction, is recovered. The naphtha fraction, or propane and butane (C.sub.3-C.sub.4) fraction, is then passed to a steam cracker for ethylene production.

Provided is a continuous process for converting waste plastic into recycle for polypropylene 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 naphtha/diesel fraction, a heavy fraction, and char. Pyrolysis oil and wax, comprising the naphtha/diesel fraction and heavy fraction, is sent to a refinery FCC unit. A liquid petroleum gas C.sub.3-C.sub.5 olefin/paraffin mixture is recovered from the FCC unit and passed to a refinery alkylation unit. A propane fraction is recovered from the alkylation unit and passed to a dehydrogenation unit to produce propylene. The propylene is passed to a propylene polymerization reactor.

Provided herein are supercritical upgrading reactors and reactor systems for upgrading a petroleum-based composition by using one or more supercritical upgrading reactors and one or more supercritical standby reactors that alternate functions such that the supercritical upgrading reactor is converted to a supercritical standby reactor and the supercritical standby reactor is converted to a supercritical upgrading reactor. The supercritical upgrading reactor upgrades a combined feed stream while a supercritical standby reactor delivers a cleaning fluid into the supercritical standby reactor. The supercritical reactors may have one or more catalyst layers and one or more purging fluid inlets, and the catalyst layers may have differing void volume ratios.

Apparatus and processes herein provide for converting hydrocarbon feeds to light olefins and other hydrocarbons. The processes and apparatus include, in some embodiments, feeding a hydrocarbon, a first catalyst and a second catalyst to a reactor, wherein the first catalyst has a smaller average particle size and is less dense than the second catalyst. A first portion of the second catalyst may be recovered as a bottoms product from the reactor, and a cracked hydrocarbon effluent, a second portion of the second catalyst, and the first catalyst may be recovered as an overhead product from the reactor. The second portion of the second catalyst may be separated from the overhead product, providing a first stream comprising the first catalyst and the hydrocarbon effluent and a second stream comprising the separated second catalyst, allowing return of the separated second catalyst in the second stream to the reactor.

Supercritical upgrading reactors and reactor systems are provided for upgrading a petroleum-based composition using one or more purging fluid inlets to prevent plugging of the catalyst layer in the reactor. Processes for upgrading petroleum-based compositions by utilizing a reactor having at least one purging fluid inlet are also provided.

A method for producing alkene gases from a cracked product effluent, the method comprising the steps of introducing the cracked product effluent to a fractionator unit, separating the cracked product effluent in the fractionator to produce a cracked light stream and a cracked residue stream, wherein the cracked light stream comprises the alkene gases selected from the group consisting of ethylene, propylene, butylene, and combinations of the same, mixing the cracked residue stream and the heavy feed in the heavy mixer to produce a combined supercritical process feed, and upgrading the combined supercritical process feed in the supercritical water process to produce a supercritical water process (SWP)-treated light product and a SWP-treated heavy product, wherein the SWP-treated heavy product comprises reduced amounts of olefins and asphaltenes relative to the cracked residue stream such that the SWP-treated heavy product exhibits increased stability relative to the cracked residue stream.