Phenol, also known as carbolic acid, is a colorless needle-like crystal with special odor. It is an important chemical raw material, widely used in phenolic resin, dyes, medicine, pesticides, plastics, synthetic fibers, spices, synthetic detergents and other fields. However, phenol wastewater mainly comes from petrochemical industry, ceramic production process, wood and resin plants using phenol as raw materials, etc. These wastewater contain high concentration of phenol, and the composition is complex, and it is difficult to treat. Direct discharge of untreated phenol wastewater will seriously affect the quality of water environment and ecological safety. Therefore, it is very important to adopt effective treatment technology to treat phenol wastewater. As a new, fast and efficient equipment for liquid-liquid mixing and separation, the combined extraction centrifugal extractor has shown remarkable advantages in the treatment of phenol wastewater.

Working principle of combined extraction centrifugal extractor

The combined extraction centrifugal extractor uses the motor to drive the drum to rotate at high speed, and the two liquids with different densities and non-mismixing complete mixed mass transfer under the action of the shear force generated by the drum or blade rotation, and then rapidly separate under the action of the centrifugal force generated by the high-speed rotation of the drum. In each stage, it can be mixed once and clarified once, and the multistage operation is to connect each stage in series, and the two-phase material flows continuously countercurrent step by step.

Phenol wastewater treatment technology

The process of treating phenol wastewater usually includes pretreatment, biological treatment, chemical treatment and physical treatment. Among them, centrifugal extraction as a physical process, has the advantages of less equipment investment, small footprint, simple operation, and can effectively recover the main pollutants.

In actual operation, the wastewater containing phenol is injected into the centrifugal extractor with suitable extractant (such as toluene, dichloromethane, etc.) in a certain proportion. Under the high-speed rotation of the drum, the two phases are quickly mixed and dispersed through the impeller to complete the mixed mass transfer process. The mixed liquid enters the rotating drum under the action of eddy disk, and under the action of centrifugal force, the two-phase liquid is quickly separated and discharged through different outlets to complete the two-phase separation process.

Extraction effect and optimization

The factors affecting the effect of centrifugal extraction include mixing strength, contact time, temperature and substance concentration difference. By increasing the speed, optimizing the blade design, adjusting the flow rate and other measures, the mixing strength can be increased, the contact time can be extended, and the mass transfer efficiency can be improved. At the same time, selecting the appropriate extractant and optimizing the pH value and other conditions can also significantly improve the extraction effect.

In practical application, the removal rate of phenol can be significantly increased by multistage extraction. For example, after primary extraction, phenol wastewater changed from dark brown to light yellow, and COD removal rate decreased significantly. After secondary extraction, the wastewater changed from light yellow to colorless and transparent, and the COD removal rate was greater than 99%.

The combined extraction centrifugal extractor shows the characteristics of high efficiency, environmental protection and economy in the treatment of phenol wastewater, and is an effective means to achieve the standard discharge of phenol wastewater and the recovery and utilization of resources. With the continuous progress of technology and the continuous promotion of applications, centrifugal extractors will play a more important role in the field of environmental protection.