Coal tar three-phase separation technology and its application

Coal tar is an important chemical raw material with high economic value. However, the components in coal tar are complex, and effective separation and purification have always been a difficult problem in the chemical industry. This paper mainly introduces the principle, method and application of coal tar three-phase separation technology in actual production, aiming to provide theoretical guidance and practical reference for the comprehensive utilization of coal tar. 1. Introduction Coal tar is a by-product of the coking industry, which mainly comes from the raw coal gas produced in the coking process. Coal tar is rich in a variety of organic compounds and has a high utilization value. However, the composition of coal tar is extremely complex, containing a variety of components with different boiling points and different polarities, making the separation and purification of coal tar a challenging task. In recent years, three-phase separation technology has achieved remarkable results in the treatment of coal tar, providing new ideas for the comprehensive utilization of coal tar. 2. Principle of coal tar three-phase separation technology Coal tar three-phase separation technology is a method of separation based on the differences in boiling points, polarity and density of each component in coal tar. This technology divides coal tar into three phases: light oil phase, medium oil phase and heavy oil phase. The light oil phase is mainly composed of low-boiling alkyl aromatics, the medium oil phase mainly contains polycyclic aromatic compounds, and the heavy oil phase is mainly composed of high-boiling asphaltenes and nitrogen-containing compounds. 3. Three-phase separation method of coal tar 1. Distillation method: By controlling the distillation temperature, the light oil phase, medium oil phase and heavy oil phase in coal tar are separated in turn. The distillation method is simple to operate, but the separation effect is affected by temperature and pressure. 2. Extraction method: The light oil phase, medium oil phase and heavy oil phase in coal tar are separated by utilizing the difference in interaction between the extractant and the components in coal tar. The extraction method has a good separation effect, but the selection of the extractant and the operating conditions have a great influence on the separation effect. 3. Crystallization method: By changing the temperature and pressure, the light oil phase, medium oil phase and heavy oil phase in coal tar are crystallized separately to achieve separation. The crystallization method has a good separation effect, but the operating conditions are relatively harsh. IV. Application of coal tar three-phase separation technology 1. Refining light oil: Coal tar three-phase separation technology can effectively separate the light oil phase in coal tar to obtain high-purity light oil. Light oil is an important chemical raw material and can be used to produce plastics, synthetic rubber, synthetic fibers, etc. 2. Extraction of medium oil: Coal tar three-phase separation technology can separate the medium oil phase in coal tar. The medium oil phase is rich in polycyclic aromatic compounds and can be used to produce dyes, drugs, pesticides, etc. 3. Asphalt production: Coal tar three-phase separation technology can separate the heavy oil phase in coal tar. The heavy oil phase is mainly composed of asphaltene and nitrogen-containing compounds. Asphalt is an important building material and can be used in roads, waterproofing and other fields. 4. Comprehensive utilization of resources: Coal tar three-phase separation technology can achieve the effective separation of various components in coal tar, which provides the possibility for the comprehensive utilization of coal tar. The components obtained by separation can be further processed to produce high value-added products to improve the utilization efficiency of coal tar resources. V. Conclusion Coal tar three-phase separation technology is an efficient and green coal tar separation method with broad industrial application prospects. Through this technology, the components in coal tar can be effectively separated and the utilization efficiency of coal tar resources can be improved. With the continuous development of science and technology, coal tar three-phase separation technology will play an increasingly important role in the comprehensive utilization of coal tar.