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Time：2025-03-26 14:22:11 Reading volume：
Waste oil purification, filtration and decolorization technology is an important means of environmental protection and resource recycling. It removes impurities and pigments in waste oil through a series of physical, chemical, or biological processes, so that it can be restored to or close to the quality of crude oil, and then realize the reuse of waste oil. The following will introduce several major waste oil decolorization technologies and their characteristics in detail.
Adsorption is one of the decolorization methods widely used in the field of oil refining. It uses the porosity and large specific surface area characteristics of the adsorption material to adsorb impurities such as pigments and colloids in the waste oil on its surface, thereby achieving the purpose of decolorization. Commonly used adsorption materials include white clay, diatomaceous earth, attapulgite and activated carbon.
Under high temperature (usually 105-120°C) and vacuum (about 266Pa), the adsorption material is mixed with the waste oil so that the adsorption material can fully adsorb the pigments and impurities in the waste oil. After some time, the adsorption material is separated from the waste oil by filtering equipment to obtain the decolorized waste oil.
Advantages: The adsorption method is simple to operate, has low requirements for equipment, and can effectively remove pigments and impurities in waste oil.
Disadvantages: For some darker waste oils, the decolorization effect may not be ideal; at the same time, a certain amount of neutral oil will be lost during the decolorization process, reducing the utilization rate of waste oil; in addition, the recycling or harmless treatment of waste decolorizers is also a problem that manufacturers need to consider.
Chemical decolorization mainly uses strong oxidizing substances such as benzoyl peroxide and hydrogen peroxide as auxiliary agents to destroy the pigment molecules in the waste oil through oxidation, thereby achieving the purpose of decolorization. This method is mainly used for the decolorization of industrial oils and fats.
Under suitable conditions, strong oxidizing substances are added to the waste oil to cause an oxidation reaction with the pigment molecules in the waste oil to generate soluble oxides or low molecular weight compounds, and then these substances are removed from the waste oil by separation.
Advantages: The decolorization effect is significant and the pigment in the waste oil can be quickly removed.
Disadvantages: Decolorized waste oil is easy to reverse color under high temperature conditions, affecting its normal use; in addition, chemical decolorization is strictly prohibited for oils and fats in the fields of food, cosmetics, etc., because there may be chemical residue problems.
Distillation decolorization technology mainly uses the principle of different boiling points of different substances to evaporate the low-boiling-point components (such as gasoline, diesel, etc.) in the waste oil by heating, while the high-boiling-point pigments and impurities remain in the distillation kettle, thereby achieving the purpose of decolorization. This method is particularly common in the decolorization of high-viscosity waste oils such as waste engine oil.
1. Transport the waste oil to the distillation kettle, start the heating system, and start the stirring device at the same time to increase the heat transfer rate of the waste oil and prevent impurities such as colloids and asphalt from coking and blocking the distillation device.
2. As the temperature gradually increases, the low-boiling point components (such as gasoline) in the waste oil are distilled out first, cooled by the condenser and collected.
3. When the temperature reaches a certain level (such as 160°C), switch to the diesel production line and continue to distill the diesel component.
4. Finally, the high-boiling-point pigments and impurities remain in the distillation kettle and are disposed of harmlessly through subsequent treatment methods.
Advantages: Distillation decolorization can effectively remove low-boiling-point components and some pigments in waste oil, and improve the utilization rate of waste oil; at the same time, the process does not require the use of chemical additives, which meets the requirements of green environmental protection.
Disadvantages: The removal effect of high-boiling-point pigments and impurities is limited; in addition, the distillation process consumes a lot of energy and the equipment investment is large.
Biological decolorization technology is an emerging waste oil decolorization method. It uses the metabolism of microorganisms to degrade pigments and impurities in waste oil into harmless substances. This method has the advantages of environmental protection and high efficiency, but it is still in the research and development stage.
Screen microbial strains with high-efficiency degradation ability, inoculate them into the culture medium containing waste oil, and control the appropriate environmental conditions (such as temperature, pH value, ventilation, etc.) to make the microorganisms multiply and secrete degradation enzymes. These enzymes can act on the pigments and impurity molecules in the waste oil and degrade them into harmless small molecules.
Advantages: Biological decolorization has the advantages of environmental protection, high efficiency, and no secondary pollution; at the same time, the microbial degradation process can also produce some beneficial by-products (such as biosurfactants).
Disadvantages: Microorganisms are sensitive to environmental conditions and require strict control of operating conditions; in addition, the biological decolorization speed is relatively slow, and the degradation effect may be poor for certain types of pigments and impurities.
There are many waste oil purification, filtration and decolorization technologies, each with its advantages and disadvantages. In practical applications, the appropriate decolorization method should be selected based on the type, quality and treatment requirements of the waste oil. With the continuous advancement of science and technology and the increasing awareness of environmental protection, waste oil decolorization technology will be more widely used and developed.
