scraper film evaporator

Product application:

In the heat exchange engineering, the scraper film evaporator is widely used. Especially for the heat exchange (short time) of heat-sensitive materials, the film scraper is conducive to the heat exchange, and through different film scraper design, it can carry out distillation of complex products.

Product details

The scraper film evaporator is a new type of high-efficiency evaporator, which is forced to form film by rotating the scraping film machine, and flows at high speed, with high heat transfer efficiency and short residence time (about 10-50 seconds), and can be used for falling-film evaporation under vacuum condition.

The material enters the evaporator radially from above the heating zone; The material is distributed to the heating wall of the evaporator through the distributor, and then the rotating film scraper wipes the material continuously and uniformly on the heating surface into a liquid film of uniform thickness and pushes it downward in a spiral shape. In this process, the rotating scraper ensures the continuous and uniform liquid film to produce high-speed turbulence, and prevents the liquid film from coking and scaling on the heating surface, so as to improve the total transfer coefficient. The light components are evaporated to form a steam flow to rise, and then pass through the vapor-liquid separator to the external condenser directly connected with the evaporator; the heavy components are discharged from the cone at the bottom of the evaporator.

A unique distributor not only spilt the material evenly into the inner wall of the evaporator, prevent the material spilled into the evaporator into the steam stream, but also prevents the incoming materials from being flashed here, which is conducive to the elimination of foam, and the material can only be evaporated along the heating surface.The upper part of the scraping film evaporator is equipped with a centrifugal separator designed according to the material characteristics to separate the liquid drop in the rising steam flow and return it to the distributor.

Several characteristics of scraping film evaporator

1、Low vacuum pressure drop:

here is a certain pressure difference between the material vaporized gas from the heating surface and the external condenser. In general evaporators, this pressure drop (Δ P) is usually high, sometimes even too high to accept. The scraper film evaporator has a large gas passage space, and the pressure in the evaporator can be regarded as almost equal to the pressure in the condenser, so the pressure drop is very small and the vacuum degree can reach 5mmHg.

2、Low operating temperature:

Because of the above characteristics, the evaporation process can be maintained at a higher vacuum. Due to the increase of vacuum degree, the boiling point of the corresponding material decreases rapidly, so the operation can be carried out at a lower temperature, reducing the thermal decomposition of the product.

3、Short heating time:

Due to the unique structure of the scraper film evaporator, the scraper has the function of pumping, which makes the material stay in the evaporator for a short time; In addition, due to the high-speed turbulence of the film on the heated evaporator, the product will not stay on the evaporator surface. Therefore, it is especially suitable for evaporation of heat-sensitive materials.

4、High evaporation intensity:

The decrease of material boiling point increases the temperature difference of the same hot medium；The function of the film scraper reduces the thickness of the liquid film in turbulent state and reduces the thermal resistance. At the same time, in this process, the fouling of the material on the heating surface is restrained, and good heat exchange is accompanied. Therefore, the total heat transfer coefficient of the scraper film evaporator is increased.

5、Large operation flexibility:

It is because of the unique performance of the scraper film evaporator that it is suitable for the treatment of materials with heat sensitivity, stable evaporation, high viscosity and rapid increase of viscosity with the increase of concentration, and the evaporation process can also be stable evaporation. It can also be successfully applied to evaporation and distillation of materials with solid particles, crystallization, polymerization, scale formation and other conditions.