Re-refining is a process that transforms used oil into high-quality base oil, similar to virgin base oil, by removing contaminants and impurities.
The Re-refining Process Explained
The re-refining of base oil primarily involves sophisticated processes designed to strip away the degradation products and additives accumulated during its use. The goal is to restore the oil's original properties.
The core of the process, as referenced, is the removal of major contaminants:
The contaminants, such as dirt, water, fuel, and used additives, are removed through vacuum distillation.
Following this crucial step, the process continues to ensure the oil meets stringent quality standards.
Key Stages in Base Oil Re-refining
The re-refining journey involves several steps to purify the used oil:
- Pre-treatment: Used oil is collected and often filtered to remove large particles. Water and lighter fuels might be removed through heating.
- Vacuum Distillation: This is a critical separation step. As stated in the reference, "The contaminants, such as dirt, water, fuel, and used additives, are removed through vacuum distillation." Operating under vacuum allows the oil to vaporize at lower temperatures, separating it from heavier contaminants like asphaltic materials and metals.
- Further Treatment: After distillation, the oil distillate is treated further. "The oil is then further treated to remove any remaining chemicals and provide consistent oil quality to international standards." This can involve various methods such as hydrotreating (using hydrogen to remove sulfur, nitrogen, and improve color and stability) or clay treatment to polish the oil and remove any remaining polar compounds.
- Finishing: The final product is a high-quality base oil ready to be blended with new additives to create lubricating oils, meeting specific performance requirements and international standards.
Why Re-refine?
Re-refining used oil offers significant environmental and economic benefits:
- Resource Conservation: Reduces the need for virgin crude oil extraction.
- Waste Reduction: Diverts hazardous used oil from landfills and waterways.
- Energy Savings: Requires less energy than processing crude oil into base oil.
- High-Quality Product: Produces base oil that can be just as good as virgin oil.
| Used Oil Contaminants Removed by Re-refining |
|---|
| Dirt |
| Water |
| Fuel |
| Used Additives |
| Heavy Metals |
| Asphaltic Materials |
Through these advanced processes, particularly vacuum distillation and subsequent treatments, used oil is given a new life as valuable base oil.
