A method for recovering base oil from waste lubricating oil by separating base oil range constituents from a waste lubricating oil mixture, thereafter separating higher quality base oil constituents and lower quality base oil constituents from the base oil recovered from the waste lubricating oil mixture and thereafter treating the lower quality base oil constituents to produce marketable base oil. The total base oil produced from a waste lubricating oil mixture by this process is greater than the quantity producible by previous processes using only base oil separation from the waste lubricating oil mixture or processes which use only treatment of the base oil recovered from the waste lubricating oil mixture to produce the product base oil.

We disclose a process for purification of hydrocarbons, suitable for a wide range of contexts such as refining bunker fuels to yield low-sulphur fuels, cleaning of waste engine oil (etc) to yield a usable hydrocarbon product, recovery of hydrocarbons from used tyres, recovery of hydrocarbons from thermoplastics etc, as well as the treatment of crude oils, shale oils, and the tailings remaining after fractionation and like processes. The method comprises the steps of heating the hydrocarbon thereby to release a gas phase, contacting the gas with an aqueous persulphate electrolyte within a reaction chamber, and condensing the gas to a liquid or a liquid/gas mixture and removing its aqueous component. It also comprises subjecting the reaction product to an electrical field generated by at least two opposing electrode plates between which the reaction product flows; this electrolytic step regenerates the persulphate electrolyte which can be recirculated within the process. The process is ideally applied in an environment at lower than atmospheric pressure, such as less than 1500 Pa. A wide range of hydrocarbons can be treated in this way. Used hydrocarbons such as engine oils and sulphur-contaminated fuels are prime examples, but there are a wide range of others such as hydrocarbons derived from the pyrolysis of a material having a hydrocarbon content. One such example is a mix of used rubber (such as end-of-life tyres) and used oils (such as engine oils, waste marine oils), which can be pyrolysed together to yield a hydrocarbon liquid which can be treated as above, and a residue that provides a useful solid fuel.

The invention relates to a process for the recovery of aliphatic hydrocarbons from a liquid hydrocarbon feedstock stream, which comprises aliphatic hydrocarbons and additionally comprises aromatic hydrocarbons and/or polar components, said process comprising the steps of: feeding the liquid hydrocarbon feedstock stream to a first column; feeding a first solvent stream which comprises an organic solvent to the first column at a position which is higher than the position at which the liquid hydrocarbon feedstock stream is fed; contacting at least a portion of the liquid hydrocarbon feedstock stream with at least a portion of the first solvent stream; and recovering at least a portion of the aliphatic hydrocarbons by liquid-liquid extraction of aromatic hydrocarbons and/or polar components with organic solvent, resulting in a stream comprising recovered aliphatic hydrocarbons and optionally organic solvent and a bottom stream from the first column comprising organic solvent and aromatic hydrocarbons and/or polar components.

We disclose a process for purification of hydrocarbons, suitable for a wide range of contexts such as refining bunker fuels to yield low-sulphur fuels, cleaning of waste engine oil (etc) to yield a usable hydrocarbon product, recovery of hydrocarbons from used tyres, recovery of hydrocarbons from thermoplastics etc, as well as the treatment of crude oils, shale oils, and the tailings remaining after fractionation and like processes. The method comprises the steps of heating the hydrocarbon thereby to release a gas phase, contacting the gas with an aqueous persulphate electrolyte within a reaction chamber, and condensing the gas to a liquid or a liquid/gas mixture and removing its aqueous component. It also comprises subjecting the reaction product to an electrical field generated by at least two opposing electrode plates between which the reaction product flows; this electrolytic step regenerates the persulphate electrolyte which can be recirculated within the process. The process is ideally applied in an environment at lower than atmospheric pressure, such as less than 1500 Pa. A wide range of hydrocarbons can be treated in this way. Used hydrocarbons such as engine oils and sulphur-contaminated fuels are prime examples, but there are a wide range of others such as hydrocarbons derived from the pyrolysis of a material having a hydrocarbon content. One such example is a mix of used rubber (such as end-of-life tyres) and used oils (such as engine oils, waste marine oils), which can be pyrolysed together to yield a hydrocarbon liquid which can be treated as above, and a residue that provides a useful solid fuel.

The invention relates to a process for the recovery of aliphatic hydrocarbons from a liquid hydrocarbon feedstock stream, which comprises aliphatic hydrocarbons and additionally comprises aromatic hydrocarbons and/or polar components, said process comprising the steps of: feeding the liquid hydrocarbon feedstock stream to a first column; feeding a first solvent stream which comprises an organic solvent to the first column at a position which is higher than the position at which the liquid hydrocarbon feedstock stream is fed; contacting at least a portion of the liquid hydrocarbon feedstock stream with at least a portion of the first solvent stream; and recovering at least a portion of the aliphatic hydrocarbons by liquid-liquid extraction of aromatic hydrocarbons and/or polar components with organic solvent, resulting in a stream comprising recovered aliphatic hydrocarbons and optionally organic solvent and a bottom stream from the first column comprising organic solvent and aromatic hydrocarbons and/or polar components.

A method for recovering synthetic oils from a feed stream, the method comprising separating at least a portion of the non-synthetic oil constituents from a commingled stream to produce a partially purified synthetic oil stream and one or more contaminant streams. Extracting at least a portion of the synthetic oil from the partially purified synthetic oil stream to produce a synthetic oil stream and a second contaminant stream.

A method for recovering synthetic oils from a feed stream, the method comprising separating at least a portion of the non-synthetic oil constituents from a commingled stream to produce a partially purified synthetic oil stream and one or more contaminant streams. Extracting at least a portion of the synthetic oil from the partially purified synthetic oil stream to produce a synthetic oil stream and a second contaminant stream.

An improved system and method for refining various types of used oil involves using solvents to treat used oil in a system designed to recycle the solvents and produce minimal waste byproducts. The system includes a main reactor for enabling the used oil and the solvents to react chemically and for wasted products to dissipate and separate through sedimentation. The system also includes a reservoir for providing a second opportunity for a chemical reaction and sedimentation of waste byproducts before the mixture of refined oil and solvents enter a housing unit configured to be heated to separate the refined oil from the solvents via vaporization and subsequent condensation. Thereby, the solvents are recycled and made available for reuse in further treatment of used oil.

An improved system and method for refining various types of used oil involves using solvents to treat used oil in a system designed to recycle the solvents and produce minimal waste byproducts. The system includes a main reactor for enabling the used oil and the solvents to react chemically and for wasted products to dissipate and separate through sedimentation. The system also includes a reservoir for providing a second opportunity for a chemical reaction and sedimentation of waste byproducts before the mixture of refined oil and solvents enter a housing unit configured to be heated to separate the refined oil from the solvents via vaporization and subsequent condensation. Thereby, the solvents are recycled and made available for reuse in further treatment of used oil.

Solvent extraction is applied to a hydrotreated base oil to create at least one higher quality product stream and at least one lower quality product stream, wherein the at least one higher quality product stream includes an improvement over the hydrotreated base oil in at least one of viscosity index, low temperature properties, volatility, and oxidation stability relative to that of the feedstock.