Lösungsmittelraffiniert

Lösungsmittelraffiniert, meaning solvent refined in German, refers to a process used in the petroleum industry to improve the quality of lubricating oils. This refining technique utilizes solvents to selectively remove undesirable components from base oils. The primary goal of solvent refining is to enhance properties such as viscosity index, oxidation stability, and demulsibility.

The process typically involves mixing a base oil with a solvent at a controlled temperature. The solvent is chosen for its ability to dissolve certain undesirable compounds, such as aromatics, naphthenes, and sulfur compounds, while leaving the desired paraffinic and naphthenic components in solution or as a separate phase. After mixing, the mixture is cooled, causing the undesirable components to precipitate out or form a separate layer.

The mixture is then separated, usually through filtration or decantation. The solvent is subsequently recovered from both the refined oil and the extracted undesirable components through distillation. The recovered solvent is then recycled back into the process. The result is a lubricating oil base stock with improved performance characteristics, making it suitable for a wider range of applications and operating conditions. Solvent refining is a critical step in the production of high-quality lubricating oils.