Disulfide oil (DSO) compounds recovered as a by-product of the mercaptan oxidation of a hydrocarbon refinery feedstock and their oxidized derivatives, oxidized disulfide oils (ODSO) are effective as a diluent to lower the viscosity and thereby improve the pipeline transportation properties of heavy oils, and particularly of wellhead crude oil. The use of the DSO and/or ODSO compounds as diluents converts an otherwise extremely low value or waste oil product into a valuable commodity that has utility in improving the transportation properties of heavy oils, particularly in oil field pipeline applications.

A method for recalculating the solvent power of a light oil, SP.sub.(LO recalculated), is provided. The method comprises: titrating the light oil against a reference oil, optionally in the presence of a titrant, to determine a volume fraction of the light oil at the onset of asphaltene precipitation, V.sub.(onset fraction LO), a volume fraction of the reference oil at the onset of asphaltene precipitation, V.sub.(onset fraction RO), and, where a titrant is present, a volume fraction of the titrant at the onset of asphaltene precipitation, V.sub.(onset fraction T), and determining the recalculated solvent power of the light oil, SP.sub.(LO recalculated), according to the following formula: ${\mathrm{SP}}_{\left(\mathrm{LO}\mathrm{recalculated}\right)}=\frac{(\begin{array}{c}{\mathrm{CSP}}_{\left(\mathrm{RO}\right)}-{\mathrm{SP}}_{\left(\mathrm{RO}\right)}*V_{\left(\mathrm{onset}\mathrm{fraction}\mathrm{RO}\right)}-\\ x*{\mathrm{SP}}_{\left(T\right)}\end{array}}{}$

Methods for making sulfide scavenging compositions are provided. The method comprises reducing a settling velocity of the sulfide scavenging composition in a fluid stream by adjusting the specific gravity of the sulfide scavenging composition to within about fifteen percent or less of the specific gravity of the fluid stream. Sulfide scavengers using the above method are also disclosed. Methods for removing sulfides from fluid streams are also provided. The methods include adding the above sulfide scavengers to fluid streams.

Systems for mixing a catalyst precursor with a heavy oil feedstock preparatory to hydroprocessing the heavy oil feedstock in a reactor to form an upgraded feedstock. Achieving very good dispersion of the catalyst precursor facilitates and maximizes the advantages of the colloidal or molecular hydroprocessing catalyst. A catalyst precursor and a heavy oil feedstock having a viscosity greater than the viscosity of the catalyst precursor are provided. The catalyst precursor is pre-mixed with a hydrocarbon oil diluent, forming a diluted catalyst precursor. The diluted precursor is then mixed with at least a portion of the heavy oil feedstock so as to form a catalyst precursor-heavy oil feedstock mixture. Finally, the catalyst precursor-heavy oil feedstock mixture is mixed with any remainder of the heavy oil feedstock, resulting in the catalyst precursor being homogeneously dispersed on a colloidal and/or molecular level within the heavy oil feedstock.

The invention provides a method for enriching diluents with butane so as not to violate pre-defined limits for liquid hydrocarbon fuels with respect to density, volatility and low density hydrocarbon content.

Disulfide oil (DSO) compounds recovered as a by-product of the mercaptan oxidation of a hydrocarbon refinery feedstock and their oxidized derivatives, oxidized disulfide oils (ODSO) are effective as a diluent to lower the viscosity and thereby improve the pipeline transportation properties of heavy oils, and particularly of wellhead crude oil. The use of the DSO and/or ODSO compounds as diluents converts an otherwise extremely low value or waste oil product into a valuable commodity that has utility in improving the transportation properties of heavy oils, particularly in oil field pipeline applications.

The invention relates to a process for the manufacture of diesel range hydrocarbons wherein a feed is hydrotreated in a hydrotreating step and isomerised in an isomerisation step, and a feed comprising fresh feed containing more than 5 wt % of free fatty acids and at least one diluting agent is hydrotreated at a reaction temperature of 200-400 C., in a hydrotreating reactor in the presence of catalyst, and the ratio of the diluting agent/fresh feed is 5-30:1.

The present invention relates to a process for converting plastic into waxes by cracking. The process comprises the steps of introducing the plastic within a reactor; allowing at least a portion of the plastic to be converted to waxes, the waxes being part of a pyrolysis gas formed within the reactor; and removing a product stream containing said waxes from the reactor. The invention also relates to a mixture of hydrocarbons obtainable by that process.

The invention provides a method for enriching diluents with butane so as not to violate pre-defined limits for liquid hydrocarbon fuels with respect to density, volatility and low density hydrocarbon content.

A method for re-refining used oils comprises contacting feedstock comprising purified used oil with extraction solvent to perform continuous liquid-liquid solvent extraction, to produce an extract stream comprising the extraction solvent and an extract dissolved in the extraction solvent. The feedstock and the extraction solvent are agitated by a variable speed agitator during the solvent extraction at a selected agitation speed. The extract is separated from the extraction solvent and subjected to a continuous flow liquid phase hydrogenation treatment to produce an oil product. A system for performing the method includes a purification unit for purifying the used oil; an extraction column for extracting the extract from the feedstock; and a continuous flow liquid phase hydrogenation unit. The extraction column comprises an agitator configured to agitate the feedstock and the extraction solvent flowing through the extraction column at a variable agitation speed.