Original title: See enough at a time: 22 kinds of evaporation, crystallization equipment structure and working principle diagram! Source: Chemical 707 Forum 1 Central-circulation tubular evaporator The heating chamber of the central circulation tube evaporator is composed of a vertical heating tube bundle (boiling tube bundle). In the center of the tube bundle, there is a tube with a larger diameter, called the central circulation tube, whose cross-sectional area is generally 40-100% of the total cross-sectional area of the heating tube bundle. When the heating medium is introduced between the tubes for heating, since the heated area of the liquid per unit volume in the heating tube is larger than that in the central circulating tube, the relative density of the liquid in the heating tube is small, resulting in a density difference between the liquid in the heating pipe and that in the central circulating tube, which causes the solution to flow in a natural circulation of descending from the central circulation tube and then ascending from the heating pipe. The circulation speed of the solution depends on the density difference produced by the solution and the length of the tube. The greater the density difference, the longer the tube, and the greater the circulation speed of the solution. However, this type of evaporator is limited by the total height, so the length of the heating tube is short, generally 1 ~ 2 m, the diameter is 25 ~ 75 mm, and the length-diameter ratio is 20 ~ 40. Performance characteristics: The central circulation tube evaporator has the advantages of compact structure, convenient manufacture and reliable operation, so it is widely used in industry and is known as the so-called "standard evaporator". But in fact, due to the limitation of structure, its circulation speed is relatively low (generally below 0.5m/s); and because the solution circulates continuously in the heating tube, its concentration is always close to the concentration of the finished solution, so the boiling point of the solution is high and the effective temperature difference is reduced. In addition, the cleaning and maintenance of the equipment is not convenient enough. 2 Externally heated evaporator The structural feature of the externally heated evaporator is that the heating chamber is separated from the separation chamber, which not only facilitates cleaning and replacement, but also reduces the total height of the evaporator. Because the heating pipe is long (the ratio of the pipe length to the pipe diameter is 50-100), and the solution in the circulating pipe is not heated, the circulating speed of the solution is high, which can reach 1.5m/s. 3 Rising film evaporator The heating chamber of the rising film evaporator is composed of one or several vertical long tubes. The diameter of the heating tube is usually 25 ~ 50mm, and the ratio of the tube length to the tube diameter is 100 ~ 150. After being preheated, the raw material liquid enters from the bottom of the evaporator, and the heated steam is condensed outside the tube. When the solution is heated and boiled, it vaporizes rapidly, and the generated secondary steam ube group is immersed in the box (or pool, tank) filled with secondary refrigeranment. The heat medium enters that heat chamber through the central steam pipe, and there is an annular channel between the outer wall of the heating cham and the inner wall of the evaporator shell, which acts like a central circulating pipe. During operation, the solution descends along the annulus and ascends along the heating tube, forming a natural circulation. Generally, wiped film evaporator ,molecular distillation systems, the cross-ows downward along the inner wall of the tube in a film shape and is evaporated and concentrated. The vapor-liquid mixture enters the separation chamber from tering the equipment. These crystal nuclei are suspended in the solution and grow into crystals as the solution moves slowly in the tank. And finally discharging from the other end of the crystallization tank. 22 Vacuum crystal boiling pot It is suitable for products with fast crystallization speed, easy natural crystallization and large crystal requirement, and can control the evaporation speed and feeding speed of the solution with simple structure. Pay attention to our energy-saving internal reference public micro-signal: jnnc01 We insist on original depth or selected every article, welcome to pay attention and share. If you need to reprint, please be sure to indicate the source, and retain the words "energy-saving internal reference" and two-dimensional code. I also hope to know more like-minded friends through this platform, communicate with each other, learn from each other, make progress together, and make a contribution to the cause of green environmental protection! 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