Today, the problem of waste oil is quite acute and requires effective methods and approaches to its solution. To understand the full extent of the problem, it is enough to look at only one fact: the amount of waste oil drained into water bodies and soil significantly exceeds the amount of the same substances entering the environment in case of accidents. The financial aspect is equally important. The high cost of lubricants makes their regeneration (at least partially) a reasonable and feasible solution. Purification and regeneration technologies can significantly extend the service life of petroleum oils. For example, transmission oil is recovered and sold through trading networks, and then poured back into gearboxes. There is also the option of converting them into fuel oil.
The origin of waste oil also has a huge impact on the selection of its disposal method. For example, emulsions for rolled aluminum are purified directly at steel mills and are re-used there for their intended purpose.
In general, the methods of waste oil disposal can be divided into several groups:
- Extending waste oil service life directly in the place of use;
- Partial recovery of lost performance with the extension of oil service life;
- Using waste oil as a part in the process of preparation of new marketable products in refineries;
- Regeneration of waste oil. The advantage of this method is that it can be repeated many times over. Experts note that regeneration is an ideal way of restoration of the original state of waste oil. This makes it possible to achieve maximum economy of oil resources.
- Dehydration. This recycling method involves removal of water from waste oil, followed by its further use as a heat carrier. In fact, it’s burning of dewatered waste oil for heating of industrial and residential premises. Since this type of recycling is a one time deal, it is not considered very efficient. But the obvious advantage of this approach is the opportunity to generate low cost electricity and heat;
- Thermal cracking. Application of this process does not enable restoration of waste oil. In this case, the waste product is converted into fuel which resembles diesel oil. The area of application of this material mainly comes down to domestic purposes, including heating. Cracking is also considered a good recycling option because it yields 85% of the original amount of raw materials;
- Physico-chemical recycling methods. This group of methods includes a variety of techniques. We’ll consider the most common ones.
Coagulation is the precipitation of various impurities dissolved in the oil. To ensure the binding of waste particles, special coagulants are used. This approach requires strict maintenance of a certain temperature, reagent dosage, as well as heavy oil mixing. In general, it takes about half an hour for the impurities to settle, and then the oil product undergoes treatment by sedimentation, filtration or separation.
Adsorption treatment is based on the ability of some substances to attract contaminants and then absorb them in their granules. Natural minerals (clay, bauxites, zeolites) usually act as adsorbents. It is possible to use substances specifically synthesized by scientists for this purpose: silumin, silica gel, aluminum oxide etc.
Ion-exchange treatment is the removal of foreign impurities that are prone to decomposition into ions in solution. For this process, oil is mixed with ionite particles, then substitution of ions in the crystal lattice occurs: “pure” ions take the place of “dirty” ones. The used ion exchangers naturally lose their original properties; therefore they must be restored by solvent treatment, drying and activation with caustic soda solution. Ion-exchange treatment shows good results in removing acidic components, but it is unable remove resins.
Selective treatment helps clean waste oil from nitrites, oxides, sulfur compounds, thus reducing its viscosity-temperature behavior. This method of processing oil which has lost its operational properties requires the use of a variety of liquid synthetic solvents.
GlobeCore is one of the leading manufacturers and suppliers of equipment for purification and recovery of various petroleum products, ranging from transformer oil to heating oil. GlobeCore uses the latest technology to restore the operating parameters of waste oils, which makes it possible to re-use it for its intended purpose. To meet the needs of its customers, GlobeCore is ready to offer both stock and customized equipment.