The working principle of DTB evaporation crystallizer
DTB evaporation crystallizer uses evaporation to partially dissolve to achieve supersaturation of the solution. DTB evaporation crystallizer is very similar in principle and structure to the evaporator used for ordinary solution concentration. Although ordinary evaporators can tolerate solids during operation precipitation. However, it is difficult to achieve effective control of the grading of the crystal grains, so there is often a difference between the DTB evaporation crystallizer and the ordinary evaporator.
DTB evaporation crystallizer is divided into: forced circulation evaporation crystallizer, continuous evaporation crystallizer, DTBB evaporation crystallizer.
The forced circulation evaporative crystallizer is abbreviated as FCC crystallizer, which is composed of a crystallization chamber, a circulation pipe, a circulation pump, and a heat exchanger. The crystallization chamber has a conical bottom. After the crystal slurry is discharged from the cone bottom, it is pumped through the heat exchanger with an axial flow circulating pump through the circulating pipe. After being heated or condensed, it enters the crystallization chamber again, so the cycle is endless, so this kind of crystallizer Belongs to the crystal slurry circulation type. The crystal slurry discharge port is located close to the bottom of the cone of the crystallization chamber, and the feed port is located at a lower position below the discharge port. FC type crystallizer can be generally used for crystallization by evaporation method, partition wall condensation method or vacuum condensation method. The particle size of the product is about 0.9~5mm.
DTB evaporation crystallizer is a guide tube-baffle evaporation crystallizer, and it is also a crystal slurry circulating crystallizer. The lower part of the vessel is connected with an elutriation column, and the vessel is equipped with a diversion tube and a cylindrical baffle. During operation, the hot saturated solution is continuously added to the lower part of the circulation pipe, mixed with the mother liquor with small crystals in the circulation pipe, and then pumped to the heater. The heated solution flows into the crystallizer near the bottom of the guide tube, and is sent to the liquid surface by the slowly rotating propeller along the guide tube. The solution evaporates and condenses on the liquid surface, and reaches a supersaturated state. Part of the solute deposits on the surface of the suspended particles, causing the crystals to grow. There is also a settlement zone around the annular baffle.
Continuous evaporative crystallizer is mainly suitable for the evaporation and crystallization of crystal precipitation solution, and is widely used in chemical industry, metal mining smelting, pickling waste liquid in large steel plants, and wet desulfurization waste liquid treatment in power plants. In view of the characteristics and complexity of various solutions in various factories, our company will make specific technical solutions for the composition and content of the solutions provided by users with crystal precipitation for customers' reference and selection of equipment. This equipment is composed of heaters and forced circulation. Pumps, evaporative separators, crystallizers, condensers, various material pumps, condensate pumps, vacuum pumps, operating platforms, electrical instrument control cabinets, and internal pipeline valves.
The main advantages of DTB evaporation crystallizer: According to the characteristics of the material and the size of the evaporation capacity, it can be designed as a single-effect or multi-effect evaporation unit. The uniquely designed crystallizer can meet the process requirements of continuous feeding and continuous discharging. The forced circulation of the evaporator forms the best match. The internal structure of the evaporator allows the crystal and the clear liquid to be effectively and quickly separated. The entire process For evaporation under vacuum conditions, the temperature is relatively low, the evaporation speed is fast, the evaporation consumption is low, and the evaporation concentration is high. It makes the solution with larger concentration easy to flow and evaporate, and it is not easy to freeze. It is one of the most advanced evaporation equipment combined with crystallization in the world.