The invention relates to a utility fluid, such as a fluid containing aromatic and non-aromatic ringed molecules, useful as a diluent when hydroprocessing pyrolysis tar, such as steam cracker tar. The specified utility fluid comprises ≧10.0 wt % aromatic and non-aromatic ring compounds and each of the following: (a) ≧1.0 wt % of 1.0 ring class compounds; (b) ≧5.0 wt % of 1.5 ring class compounds; (c) ≧5.0 wt % of 2.0 ring class compounds; and (d) ≦0.1 wt % of 5.0 ring class compounds. The invention also relates to methods for producing such a utility fluid and to processes for hydroprocessing pyrolysis tar.

A process and apparatus is for recycling LCO and/or HCO to an FCC unit to recover additional distillate. Spent catalyst recycle in the FCC unit may be used to improve distillate yield. A hydroprocessing zone may saturate cycle oil aromatics for cracking in an FCC unit. The recycle cracked stream may be recycled to a downstream hydroprocessing zone to avoid a first hydroprocessing zone for hydrotreating feed to the FCC unit. Additional recovery of cycle oil for recycle is obtained by heating slurry oil prior to vacuum separation.

A process and apparatus is for recycling LCO and/or HCO to an FCC unit to recover additional distillate. Spent catalyst recycle in the FCC unit may be used to improve distillate yield. A hydroprocessing zone may saturate cycle oil aromatics for cracking in an FCC unit. The recycle cracked stream may be recycled to a downstream hydroprocessing zone to avoid a first hydroprocessing zone for hydrotreating feed to the FCC unit. Additional recovery of cycle oil for recycle is obtained by heating slurry oil prior to vacuum separation.

Disclosed is a catalytic cracking process for producing isobutane and/or light aromatics in high yield, comprising the steps of: a) providing a catalytic cracking feedstock oil having a polycyclic naphthene content of greater than about 25 wt %; b) subjecting the catalytic cracking feedstock oil to a first catalytic cracking reaction and a second catalytic cracking reaction sequentially under different reaction conditions to obtain a catalytic cracking product; c) separating the resulting catalytic cracking product to obtain a liquefied gas fraction comprising isobutane and a gasoline fraction comprising light aromatics; and d) optionally, recovering isobutane from the liquefied gas fraction and/or recovering light aromatics from the gasoline fraction. The process can enable the production of isobutane and/or light aromatics in high yield.

The present invention utilizes mechanical vapor compression and/or thermal vapor compression integrating compression loops across multiple process stages. A sequential network of compressors is utilized to increase the pressure and condensing temperature of the vapors within each process stage, as intra-vapor flow, and branching between process stages, as inter-vapor flow. Because the vapors available are shared among and between compressor stages, the number of compressors can be reduced, improving economics. Balancing vapor mass flow through incremental compressor stages which traverse multiple process stages by splitting vapors between compressor stages enables the overall vapor-compression system to be tailored to individual process energy requirements and to accommodate dynamic fluctuations in process conditions.

The present invention utilizes mechanical vapor compression and/or thermal vapor compression integrating compression loops across multiple process stages. A sequential network of compressors is utilized to increase the pressure and condensing temperature of the vapors within each process stage, as intra-vapor flow, and branching between process stages, as inter-vapor flow. Because the vapors available are shared among and between compressor stages, the number of compressors can be reduced, improving economics. Balancing vapor mass flow through incremental compressor stages which traverse multiple process stages by splitting vapors between compressor stages enables the overall vapor-compression system to be tailored to individual process energy requirements and to accommodate dynamic fluctuations in process conditions.

A method of producing a fuel additive includes passing a feed stream comprising C4 hydrocarbons through a butadiene extraction unit producing a first process stream; passing the first process stream through a methyl tertiary butyl ether unit producing a second process stream and a methyl tertiary butyl ether product; passing the second process stream through a hydration unit producing the fuel additive and a recycle stream; passing the recycle stream through a hydrogenation unit; and recycling the recycle stream to a steam cracker unit and/or to the feed stream

Provided herein is a unique process that prepares a saturated hydrocarbon mixture with well-controlled structural characteristics that address the performance requirements driven by the stricter environmental and fuel economy regulations for automotive engine oils. The process allows for the branching characteristics of the hydrocarbon molecules to be controlled so as to consistently provide a composition that has a surprising CCS viscosity at −35° C. (ASTM D5329) and Noack volatility (ASTM D5800) relationship. The process comprises providing a specific olefinic feedstock, oligomerizing in the presence of a BF.sub.3 catalyst, and hydroisomerizing in the presence of a noble-metal impregnated, 10-member ring zeolite catalyst.

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.

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.