Research progress on electric desalting and dehydration technology of coal tar

The impurities of water,inorganic salts,metals and solid contained in coal tar have adverse effects for the subsequent processing device and also can reduce the quality of secondary processing raw materials and follow-up products.Therefore,in the process of coal tar processing,it is necessary to pretreat coal tar first.Compared with other pretreatment technologies,the desalting and dehydration technology of coal tar has a lot of developing room,such as wide adaptability to raw materials,less condensation coke and good desalting and dewatering effect.The principle of electric desalting and dehydration of coal tar was briefly described.The research hotspots of coal tar electric desalting and dehydration technology in the aspect of demulification were summarized,including the mechanism and kinetics of demulification,the effects of amount and types of demulsifier on demulsification efficiency.Then the improvement of electric desalting and dehydration technologies based on the characteristics of coal tar and the problems and corresponding countermeasures in industrial applications were discussed.Finally,it is proposed that the main research and development directions in the future are to develop a new type of emulsifiers,and compound the emulsifiers and combine a variety of desalting and dehydration techniques.