Can vacuum pumps be used instead of diffusion pumps in the molecular distillation process for waste oil?

Petroleum is a non-renewable resource, and the rapid development of industry and the increasing energy demands of modern society have led to excessive use and consumption of oil. During the refining, storage, transportation, and use of oil, the entry of moisture and impurities may occur. Due to breathing action, oxidation by temperature and air, or other factors, oil can age and deteriorate. The presence of pollutants in the oil accelerates further degradation and decomposition, producing harmful gases like sulfur dioxide. This alters the oil's physical and chemical properties, such as color, acid value, viscosity, flash point, breakdown voltage, and water content. When the level of pollutants in the oil exceeds the required standards or when the physical and chemical indicators are out of a certain standard range, it becomes waste oil. Waste oil contaminated and not properly recycled not only results in waste but also causes serious environmental pollution.

Waste oil regeneration methods include processes such as flocculation extraction, solvent refining, membrane filtration, and molecular distillation. Molecular distillation technology utilizes the difference in the average free path of molecules between different fractions, achieving separation between distillates by increasing temperature and reducing pressure. It features low operating temperature, low distillation pressure, short oil heating time, and excellent separation effects.

In the molecular distillation process, essential equipment includes vacuum pumps, high vacuum metering pumps, insulation metering pumps, and vacuum conveying pumps, among others. But do we still need a diffusion pump? Firstly, a diffusion pump is a type of vacuum booster pump used for achieving high vacuum (ultimate vacuum of 10-4 to 10-5 Pa). Therefore, a diffusion pump must be paired with a primary pump to function (suction pressure of 10-1 to 10-4 Pa) and cannot directly draw atmospheric pressure.
Next: Determine the required vacuum level for the molecular distillation equipment to decide on the appropriate vacuum pump or pump set.

For varying operational conditions and processes, different vacuum pumps are required. Welcome to call Lujù to discuss together.