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.

The present invention discloses an integrated process scheme for producing (i) high-octane gasoline blending stream (ii) high aromatic heavy naphtha stream which is a suitable feedstock for benzene, toluene, and xylene (BTX) production and (iii) high cetane ultra-low sulphur diesel (ULSD) stream suitable for blending in refinery diesel pool.

Processes for producing olefins include integration of steam cracking with a dual catalyst metathesis process. The processes include steam cracking a hydrocarbon feed to form a cracking reaction effluent containing butenes, separating the cracking reaction effluent to produce a cracking C4 effluent including normal butenes, isobutene, and 1,3-butadiene, subjecting the cracking C4 effluent to selective hydrogenation to convert 1,3-butadiene in the cracking C4 effluent to normal butenes, removing isobutene from a hydrogenation effluent to produce a metathesis feed containing normal butenes, and contacting the metathesis feed with a metathesis catalyst and a cracking catalyst directly downstream of the metathesis catalyst to produce a metathesis reaction effluent. Contacting with the metathesis catalyst causes metathesis of normal butenes to produce ethylene, propene, and C5+ olefins, and contacting with the cracking catalyst causes C5+ olefins produced through metathesis to undergo cracking reactions to produce additional propene, ethylene, or both.

Processes for producing olefins include integration of steam cracking with a dual catalyst metathesis process. The processes include steam cracking a hydrocarbon feed to form a cracking reaction effluent containing butenes, separating the cracking reaction effluent to produce a cracking C4 effluent including normal butenes, isobutene, and 1,3-butadiene, subjecting the cracking C4 effluent to selective hydrogenation to convert 1,3-butadiene in the cracking C4 effluent to normal butenes, removing isobutene from a hydrogenation effluent to produce a metathesis feed containing normal butenes, and contacting the metathesis feed with a metathesis catalyst and a cracking catalyst directly downstream of the metathesis catalyst to produce a metathesis reaction effluent. Contacting with the metathesis catalyst causes metathesis of normal butenes to produce ethylene, propene, and C5+ olefins, and contacting with the cracking catalyst causes C5+ olefins produced through metathesis to undergo cracking reactions to produce additional propene, ethylene, or both.

A system for hydrogenation C.sub.3 and C.sub.4 acetylenes contained within a hydrocarbon stream generated in a stream cracker unit where a debutanizer is placed upstream of a depropanizer for more economical processing of the hydrocarbon stream to produce lighter hydrocarbons, where the system requires only one stripper tower downstream of hydrogenation to remove residual hydrogen.

A system for hydrogenation C.sub.3 and C.sub.4 acetylenes contained within a hydrocarbon stream generated in a stream cracker unit where a debutanizer is placed upstream of a depropanizer for more economical processing of the hydrocarbon stream to produce lighter hydrocarbons, where the system requires only one stripper tower downstream of hydrogenation to remove residual hydrogen.

Petrochemical products may be produced from a hydrocarbon material by a process that may include separating the hydrocarbon material into at least a lesser boiling point fraction and a greater boiling point fraction, cracking the lesser boiling point fraction in a first reactor in the presence of a catalyst at a reaction temperature of from 500° C. to 700° C. to produce a first cracking reaction product, and cracking the greater boiling point fraction in a second reactor in the presence of the catalyst at a reaction temperature of from 500° C. to 700° C. to produce a second cracking reaction product. The hydrocarbon material may be crude oil. The first reactor may be a riser, and the second reactor may be a downer. The catalyst may be passed from the first reactor to the second reactor, from the second reactor to a regenerator, and from the regenerator to the first reactor, such that the catalyst is circulated between the first reactor, second reactor, and regenerator. An amount of coke may be reduced on the catalyst in the regenerator.

Systems and methods are provided for conversion of polymers (such as plastic waste) to olefins. The systems and methods can include an initial pyrolysis stage where a plastic feedstock is delivered to the initial pyrolysis stage by one or more melt extruders. The one or more melt extruders can be heated to maintain the plastic feedstock in a liquid state during delivery of the plastic feedstock to the initial pyrolysis stage. This can allow for delivery of the plastic feedstock into the pyrolysis process with a controlled distribution of plastic into the pyrolysis reactor.

Systems and methods are provided for conversion of polymers (such as plastic waste) to olefins. The systems and methods can include an initial pyrolysis stage where a plastic feedstock is delivered to the initial pyrolysis stage by one or more melt extruders. The one or more melt extruders can be heated to maintain the plastic feedstock in a liquid state during delivery of the plastic feedstock to the initial pyrolysis stage. This can allow for delivery of the plastic feedstock into the pyrolysis process with a controlled distribution of plastic into the pyrolysis reactor.

The invention relates to C.sub.5+ hydrocarbon conversion. More particularly, the invention relates to separating a vapor phase product and a liquid phase product from a heated mixture that includes steam and C.sub.5+ hydrocarbons, catalytically cracking the liquid phase product and steam cracking the vapor phase product.