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.

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.

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.

In the hydroconversion processes of heavy hydrocarbon oils, in which the hydrogen is introduced at the reactor base by bubbling, the low diffusion rate of hydrogen, from the gas phase to the reaction liquid, limits the degree of conversion. The process circumvents the obstacle of the limited amount of reactant hydrogen by using a slurry bubble column reactor which reduces the formation of light hydrocarbon products, and therefore the hydrogen required for the hydroconversion, allowing to operate at full conversion.

Compositions and methods for restoring catalytic activity by dissolving soft coke with a solvent, one method including detecting soft coke deposition on a catalyst composition; preparing an aromatic bottoms composition with a Hildebrand solubility parameter of at least about 20 SI to remove the soft coke from the catalyst composition; and washing the catalyst composition with the aromatic bottoms composition until at least a portion of the soft coke deposition is removed.

Compositions and methods for restoring catalytic activity by dissolving soft coke with a solvent, one method including detecting soft coke deposition on a catalyst composition; preparing an aromatic bottoms composition with a Hildebrand solubility parameter of at least about 20 SI to remove the soft coke from the catalyst composition; and washing the catalyst composition with the aromatic bottoms composition until at least a portion of the soft coke deposition is removed.

In the hydroconversion processes of heavy hydrocarbon oils, in which the hydrogen is introduced at the reactor base by bubbling, the low diffusion rate of hydrogen, from the gas phase to the reaction liquid, limits the degree of conversion. The process circumvents the obstacle of the limited amount of reactant hydrogen by using a slurry bubble column reactor which reduces the formation of light hydrocarbon products, and therefore the hydrogen required for the hydroconversion, allowing to operate at full conversion.

Method for starting up a method for producing kerosene and diesel fuel from hydrocarbon compounds produced by Fischer-Tropsch synthesis. The start-up method employs catalytic reaction of Fischer-Tropsch synthesis with a synthesis gas for producing a heavy hydrocarbon fraction and a light hydrocarbon fraction, a reduction (RE) reducing a hydrotreatment catalyst by ensuring contact with a gas comprising hydrogen, bringing the heavy hydrocarbon fraction into contact with the hydrotreatment catalyst (DM). During the step for ensuring contact, the temperature (TEMP) of the catalyst is increased to a temperature of between 260 C. and 360 C. Then, (TR) bringing a mixture comprising the heavy hydrocarbon fraction and the light hydrocarbon fraction into contact with the hydrotreatment catalyst is carried out.

Method for starting up a method for producing kerosene and diesel fuel from hydrocarbon compounds produced by Fischer-Tropsch synthesis. The start-up method employs catalytic reaction of Fischer-Tropsch synthesis with a synthesis gas for producing a heavy hydrocarbon fraction and a light hydrocarbon fraction, a reduction (RE) reducing a hydrotreatment catalyst by ensuring contact with a gas comprising hydrogen, bringing the heavy hydrocarbon fraction into contact with the hydrotreatment catalyst (DM). During the step for ensuring contact, the temperature (TEMP) of the catalyst is increased to a temperature of between 260 C. and 360 C. Then, (TR) bringing a mixture comprising the heavy hydrocarbon fraction and the light hydrocarbon fraction into contact with the hydrotreatment catalyst is carried out.