Molecular Separation Unit for Used Motor Oil Recycling

Texas City, TX

Koch Modular Process Systems teamed up with sister company Koch Project Solutions to support ReGen III Oil Corporation’s project to build a new re-refinery located in the U.S. Gulf Coast. The re-refinery will process used motor oil into Group II and Group III base oils. Upon completion of detailed design, construction, commissioning, and start-up, this new USGC re-refinery facility will clean and process approximately 78 million gallons of used motor oils per year. Support was more than proof-of-concept because Koch Modular’s units were already installed and working in operating facilities, which made it a natural step forward in this collaboration.


ReGen III’s re-refinery will be a Used Motor Oil (UMO) facility that will accept UMO from selected sources and process it into Group II and Group III base oils using a three-step combination of technologies including a Contaminant Separation Unit (CSU), a Molecular Separation Unit (MSU) and a Molecular Treatment Unit (MTU).

The CSU removes low boiling and high boiling molecules that are not in the base oil distillation range to achieve a desired boiling point cut. This step allows variability in feedstocks because it refines any feedstock into a similar boiling point range. The product from this stage is called Vacuum Gas Oil (VGO) and serves as the feed for the MSU.

Koch Modular is responsible for the second step, referred to as the molecular separation unit (MSU). The MSU, consisting of liquid-liquid extraction and distillation, will treat Vacuum Gas Oil (VGO) produced by the CSU. Challenges will be posed by the UMO which contain engine oil additives, debris, and combustion byproducts, including unburnt fuel, as well as direct engine wear and tear, such as metal filings. As a result, the variability of the UMO feedstock from differing sources requires Koch Modular engineers to achieve design variability to tackle these challenges.


Koch Modular is working on the design, engineering, and delivery of the MSU designed to remove contaminants such as aromatic components and polar species from the VGO in order to yield high-quality Group III base oil as the raffinate product.

During this stage, known unit operations are employed in a prescribed manner. This process involves a combination of liquid-liquid extraction and distillation. The extraction step uses a Koch SCHEIBEL® Extraction Column to remove color bodies from the VGO feedstock and improve select physical properties such as viscosity. The Raffinate stream from the column is largely removed of undesirable components of the VGO and flows to the Raffinate Stripper to further purify the Group III base oil. The Extract stream consists of a low-quality oil containing the undesirable components of the VGO and flows to a distillation column for the removal of the solvent introduced in the extraction column.


The three-step processing of UMO is unique compared to competing processes that use a two-step CEP process consisting of contamination separation and a hydrotreater units. The Contaminant Separation Unit utilizes a distillation process to separate bulk contaminants; the MSU achieves the separation of high-quality base oil molecules from lower quality base oil molecules; the MTU provides the hydro-finishing treatment of lower quality base oil molecules.

The overall design of the process allows the facility to process a broader range of feedstock qualities in the CSU. Whereas competing processes are typically producing Group I or II oils, the MSU provided by Koch Modular will provide higher-grade Group III base oils which lead to lower CAPEX in the MTU. Additionally, the MSU has relatively lower OPEX due to the recoveries of solvents.

The project is progressing on an accelerated schedule such that the commissioning of the finished re-refinery is planned to take place in the second half of 2023.