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.

A process is disclosed for the production of hydrocarbons with removal of coke from a product stream. In a first mode, hydrocarbons and steam are subjected to steam cracking to obtain a cracked gas. The removal of coke from the steam is performed using a coke trap thus obtaining a coke-depleted cracking gas which is subjected to quench heat exchange in the first mode downstream of the coke trap, effecting cooling. Product stream is formed in the first operating mode using the cracked gas cooled in the quench heat exchange. The coke trap is emptied in a second mode using a stream extracted from a cracking furnace, bypassing the quench heat exchange, to obtain a coke stream. The coke stream in the second mode is passed to a coke collector.

A process is disclosed for the production of hydrocarbons with removal of coke from a product stream. In a first mode, hydrocarbons and steam are subjected to steam cracking to obtain a cracked gas. The removal of coke from the steam is performed using a coke trap thus obtaining a coke-depleted cracking gas which is subjected to quench heat exchange in the first mode downstream of the coke trap, effecting cooling. Product stream is formed in the first operating mode using the cracked gas cooled in the quench heat exchange. The coke trap is emptied in a second mode using a stream extracted from a cracking furnace, bypassing the quench heat exchange, to obtain a coke stream. The coke stream in the second mode is passed to a coke collector.

Systems and methods for producing light olefins and BTX (benzene, toluene, and xylene). Crude oil is first separated to produce light naphtha and heavy naphtha. Light naphtha is fed to a steam cracking unit and heavy naphtha is fed to a catalytic cracking unit. The effluent from the steam cracking unit and the effluent from the catalytic cracking unit are flowed into an oil quench tower and are further separated in a separation unit to produce an ethylene stream, a propylene stream, and a BTX stream. The C.sub.4 hydrocarbons, ethane, and propane from the effluent of the steam cracking unit and the effluent from the catalytic cracking unit are recycled to the steam cracking unit. The non-BTX C.sub.6+ hydrocarbons from the effluent of the steam cracking unit and the effluent from the catalytic cracking unit are recycled to the catalytic cracking unit.

In some examples, hydrocarbon feed and a diluent such as steam are mixed, and heated. A vapor phase product and a liquid phase product can be separated from the heated mixture. The liquid phase product can be hydroprocessed to produce a first hydroprocessed product. A pitch and one or more hydrocarbon products can be separated from the first hydroprocessed product. The pitch can be contacted with a diluent to produce a pitch-diluent mixture. The pitch-diluent mixture can be hydroprocessed to produce a second hydroprocessed product. A hydroprocessor heavy product and a utility fluid product can be separated from the second hydroprocessed product. The diluent can be or include at least a portion of the utility fluid product. The vapor phase product can be steam cracked to produce a steam cracker effluent. A tar product and a process gas that can include ethylene and propylene can be separated from the steam cracker effluent.

In some examples, hydrocarbon feed and a diluent such as steam are mixed, and heated. A vapor phase product and a liquid phase product can be separated from the heated mixture. The liquid phase product can be hydroprocessed to produce a first hydroprocessed product. A pitch and one or more hydrocarbon products can be separated from the first hydroprocessed product. The pitch can be contacted with a diluent to produce a pitch-diluent mixture. The pitch-diluent mixture can be hydroprocessed to produce a second hydroprocessed product. A hydroprocessor heavy product and a utility fluid product can be separated from the second hydroprocessed product. The diluent can be or include at least a portion of the utility fluid product. The vapor phase product can be steam cracked to produce a steam cracker effluent. A tar product and a process gas that can include ethylene and propylene can be separated from the steam cracker effluent.

The invention provides a system and method for conversion of raw syngas and tars into refined syngas, while optionally minimizing the parasitic losses of the process and maximizing the usable energy density of the product syngas. The system includes a reactor including a refining chamber for refining syngas comprising one or more inlets configured to promote at least two flow zones: a central zone where syngas and air/process additives flow in a swirling pattern for mixing and combustion in the high temperature central zone; at least one peripheral zone within the reactor which forms a boundary layer of a buffering flow along the reactor walls, (b) plasma torches that inject plasma into the central zone, and (c) air injection patterns that create a recirculation zone to promotes mixing between the high temperature products at the core reaction zone of the vessel and the buffering layer, wherein in the central zone, syngas and air/process additives mixture are ignited in close proximity to the plasma arc, coming into contact with each other, concurrently, at the entrance to the reaction chamber and method of using the system.

The invention provides a system and method for conversion of raw syngas and tars into refined syngas, while optionally minimizing the parasitic losses of the process and maximizing the usable energy density of the product syngas. The system includes a reactor including a refining chamber for refining syngas comprising one or more inlets configured to promote at least two flow zones: a central zone where syngas and air/process additives flow in a swirling pattern for mixing and combustion in the high temperature central zone; at least one peripheral zone within the reactor which forms a boundary layer of a buffering flow along the reactor walls, (b) plasma torches that inject plasma into the central zone, and (c) air injection patterns that create a recirculation zone to promotes mixing between the high temperature products at the core reaction zone of the vessel and the buffering layer, wherein in the central zone, syngas and air/process additives mixture are ignited in close proximity to the plasma arc, coming into contact with each other, concurrently, at the entrance to the reaction chamber and method of using the system.

A process for producing light olefins comprising thermal cracking. Hydrocracked streams are thermally cracked to produce light olefins. A pyrolysis gas stream is separated into a light pyrolysis gas stream and a heavy pyrolysis gas stream. A light pyrolysis gas stream is separated into a normal paraffins stream and a non-normal paraffins stream. A normal paraffins stream is thermally cracked. The integrated process may be employed to obtain olefin products of high value from a crude stream.

A process for producing light olefins comprising thermal cracking. Hydrocracked streams are thermally cracked to produce light olefins. A pyrolysis gas stream is separated into a light pyrolysis gas stream and a heavy pyrolysis gas stream. A light pyrolysis gas stream is separated into a normal paraffins stream and a non-normal paraffins stream. A normal paraffins stream is thermally cracked. The integrated process may be employed to obtain olefin products of high value from a crude stream.