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.

A method of recycling waste lubricant. The method includes providing a waste lubricant-derived oil fraction, pretreating the waste lubricant-derived oil fraction, and hydrocracking the pretreated waste lubricant-derived oil fraction. The method has economic advantages in that waste lubricant can be recycled into fuel oil and high-grade lube base oil with a relatively high yield compared to a lube base oil manufacturing process utilizing only unconverted oil as a feedstock.

Proposed is a process of producing a high-quality lube base oil using a refined oil fraction obtained from waste lubricant as a feedstock. The process includes purifying waste lubricant to obtain a refined oil fraction, pretreating the refined oil fraction, and blending the pretreated refined oil fraction with unconverted oil (UCO), before or after vacuum distillation and catalytic dewaxing of the unconverted oil, or between the vacuum distillation and the catalytic dewaxing of the unconverted oil.

Methods and systems for processing a composition comprising an estolide base oil and an immiscible component. In certain embodiments, the process comprises separating an estolide base oil from immiscible components such as water. In certain embodiments, the method comprises one or more of gravity separating, coalescing, and accumulating.

A process for the enhancement of the byproducts of a process for the regeneration of exhaust oils is described, wherein said process for the regeneration of exhaust oils which includes at least one of the following steps: a) passing of the oil to be regenerated into one or more centrifuges, b) storage of the oil, before treatment, in suitable containers, c) desiloxanation and d) filtering. The byproducts of one or more of steps a) to d) are treated, gathered and mixed with one another and added to the bitumen coming out as tail of a fractioned distillation step of the above-said regeneration process of exhaust oils. A plant for the carrying out of a process according to any one of the preceding claims is also described, comprising a processing unit for each of the byproducts coming from steps a) to d) and a mixer (6) with stirring (7).

A lubricating oil purification system for purifying a stock solution mixed with ammonia water into lubricating oil, the lubricating oil purification system includes: an engine; a lubricating oil purifier configured to separate a stock solution containing the lubricating oil used in the engine into a light liquid which is at least the purified lubricating oil and a heavy liquid containing ammonia; and a water supply unit configured to supply water into a separation chamber during operation of the lubricating oil purifier.

A solvent extraction system includes an elongated solvent extraction chamber having first and second ends, at least one first port for providing a continuous phase into the solvent extraction chamber and at least one second port for removing content from the solvent extraction chamber, a dispersed phase inlet in fluid communication with the first end of the solvent extraction chamber and a membrane having pores. Diameters of the pores are from 1 to 100 m and do not differ by more than 20%, and center-to-center distances between the pores are from 10 to 1000 m and do not differ more than 20%. The membrane is positioned at the first end of the solvent extraction chamber relative to the dispersed phase inlet such that a liquid provided into the solvent extraction chamber through the dispersed phase inlet must pass through the membrane.

According to an embodiment, a method for producing a recycled lubricating base oil from waste lubricating oil is proposed, the method including a) first pretreating the waste lubricating oil, b) performing distillation to recover a fraction having a specific boiling point from the first pretreated waste lubricating oil, c) second pretreating the fraction recovered in the distillation operation, and d) hydroprocessing the second pretreated fraction in the presence of a catalyst. The recycled lubricating base oil produced by the above method has a viscosity index (VI) equal to or greater than 130. The proposed method makes it possible to produce a high-grade lubricating base oil using only waste lubricating oil as a feed, thereby reducing the cost of raw materials for production of lubricating base oil, and having the advantage of being environmentally friendly.

Provided herein are processes for recycling hydrocarbons in a used high performance lubricant such as wind turbine gear oil. In the present process and methodologies, the used high performance lubricant is not mixed with another type of used oil. The used high performance oil is contacted with a solvent in an extraction process. Contaminates are extracted and circular hydrocarbons are formed. Solvent can be recovered, and the circular hydrocarbon combined with a high performance base stock for use as a high performance lubricant in a mechanical system.

A method of recycling waste lubricant. The method includes providing a waste lubricant-derived oil fraction, pretreating the waste lubricant-derived oil fraction, and hydrocracking the pretreated waste lubricant-derived oil fraction. The method has economic advantages in that waste lubricant can be recycled into fuel oil and high-grade lube base oil with a relatively high yield compared to a lube base oil manufacturing process utilizing only unconverted oil as a feedstock.