Systems and methods for producing olefins and/or aromatics are disclosed. Methods disclosed includes aqua-processing hydro-processing of crude oils and/or heavy oils and/or residue, in an aqua-processing hydro-processing unit, to produce intermediate products, which can then be used to make valuable chemicals such as olefins and aromatics.

A process is provided for utilizing polypropylene-containing waste plastic. The process provides pyrolyzing a plastic feed in a pyrolysis reactor to obtain a pyrolysis effluent stream. The process further provides passing the pyrolysis effluent stream to a distillation column to obtain a C.sub.9 hydrocarbons rich stream which is also dimethylheptenes rich and then passing the C.sub.9 hydrocarbons rich stream to a reforming unit to provide a reformate stream. The process further provides passing the reformate stream to a transalkylation unit to provide a mixed-xylenes stream.

A feed stream of cyclic paraffins may be separated to obtain an overhead of methylcyclopentane or cyclohexane and a bottoms stream cyclohexane or methylcyclohexane. The overhead stream may be subjected to separation of normal paraffins from non-normal paraffins with the former being isomerized or the entire overhead stream may be isomerized. In a further embodiment, the bottoms stream may be subjected to steam cracking. In an additional embodiment, the feed stream of cyclic paraffins may be formerly subjected to aromatic saturation.

Systems and methods are provided for co-processing of pyrolysis tar with pre-pyrolysis flash bottoms. In some aspects, the co-processing can correspond to solvent-assisted hydroprocessing. By combining pyrolysis tar and flash bottoms with a solvent, various difficulties associated with hydroprocessing of the fractions can be reduced or minimized, such as difficulties associated with hydroprocessing of high viscosity feeds and/or high sulfur feeds. Optionally, separate solvents and/or fluxes can be used for the pyrolysis tar and the flash bottoms. The resulting upgraded products can be suitable, for example, for inclusion in low sulfur fuel oils (LSFO).

Systems and methods are provided for co-processing of pyrolysis tar with pre-pyrolysis flash bottoms. In some aspects, the co-processing can correspond to solvent-assisted hydroprocessing. By combining pyrolysis tar and flash bottoms with a solvent, various difficulties associated with hydroprocessing of the fractions can be reduced or minimized, such as difficulties associated with hydroprocessing of high viscosity feeds and/or high sulfur feeds. Optionally, separate solvents and/or fluxes can be used for the pyrolysis tar and the flash bottoms. The resulting upgraded products can be suitable, for example, for inclusion in low sulfur fuel oils (LSFO).

Processes for preparing a low particulate liquid hydrocarbon product are provided and includes blending a tar stream containing particles with a fluid to produce a fluid-feed mixture containing tar, the particles, and the fluid, and centrifuging the fluid-feed mixture at a temperature of greater than 60° C. to produce a higher density portion and a lower density portion, where the lower density portion contains no more than 25 wt % of the particles in the fluid-feed mixture.

Processes for preparing a low particulate liquid hydrocarbon product are provided and includes blending a tar stream containing particles with a fluid to produce a fluid-feed mixture containing tar, the particles, and the fluid, and centrifuging the fluid-feed mixture at a temperature of greater than 60° C. to produce a higher density portion and a lower density portion, where the lower density portion contains no more than 25 wt % of the particles in the fluid-feed mixture.

Hydrocarbon-containing fluids are provided for use during solvent-assisted hydroprocessing of pyrolysis tar, such as steam cracker tar. The hydrocarbon-containing fluids can be used at any convenient time, such as during start-up of a pyrolysis process when recycled liquid pyrolysis product is not available; when the amount of liquid pyrolysis product available for recycle is not sufficient to maintain desired hydroprocessing conditions; and/or when the changes to the quality of the liquid pyrolysis product reduce the suitability of the recycle stream for use as a utility fluid.

Hydrocarbon-containing fluids are provided for use during solvent-assisted hydroprocessing of pyrolysis tar, such as steam cracker tar. The hydrocarbon-containing fluids can be used at any convenient time, such as during start-up of a pyrolysis process when recycled liquid pyrolysis product is not available; when the amount of liquid pyrolysis product available for recycle is not sufficient to maintain desired hydroprocessing conditions; and/or when the changes to the quality of the liquid pyrolysis product reduce the suitability of the recycle stream for use as a utility fluid.

Embodiments for an integrated hydrotreating and steam pyrolysis process for the processing of crude oil comprising recycling the higher boiling point fraction of the upgraded crude oil to increase the yield of petrochemicals such as olefins and aromatics.