Falling Film Evaporator

Falling film evaporator is the main products of our company. It is a widely used product in the pharmaceutical, food and chemical industries,The most widely application is the extraction of CBD oil.

The structure of the falling film evaporator is basically the same as that of the rising film evaporator. The difference is that after preheating, the raw material liquid enters the tube evenly from the top of the evaporator through the liquid distribution device, and flows down the inner wall of the tube in a film shape under the action of gravity. and concentrated by evaporation. The gas-liquid mixture flows down and enters the separation chamber from the bottom of the heating tube. Falling film evaporator This equipment can be divided into three types according to the material performance: countercurrent, cocurrent and crossflow. The operation of the equipment is basically carried out in a negative pressure state, and the safety performance is good.

The principle of falling film evaporator:

Falling film evaporation is to add the material and liquid from the tube box on the heating chamber. Under the action of gravity, vacuum induction and airflow, the material becomes a uniform film. During the flow, the material is heated and vaporized, and the resulting vapor and liquid phases enter the separation chamber of the evaporator together. After the vapor and liquid are completely separated, the vapor enters the condenser for condensation. The medium is heated to achieve multi-effect operation, so that multi-effect operation is achieved, and the liquid phase is discharged from the separation chamber

Falling film evaporator models and components:

Equipment composition of falling film evaporator: evaporator, separator, condenser, hot pressure pump, vacuum pump, feed liquid pump, condensate water pump, operating platform, electrical instruments and valve pipelines and other systems.

1. Evaporator: tubular heat exchanger. The liquid material is heated and evaporated through the heating steam through the heating tube. The concentrated liquid and the secondary steam generated by the evaporation enter the distributor for separation, and a liquid level switch to control the water distribution is installed at the bottom.

2. Separator: It is a tank with a single-layer structure. The upper secondary steam interface is communicated with the condenser, and the lower interface is communicated with the evaporator.

3. Preheater: plate type/tube type.

4. Condenser: The secondary steam is condensed for recycling.

5. Condensate tank: a single-layer structure tank, the tank body is equipped with a liquid level switch to control the liquid level. By connecting to the pump at the outlet, the condensate in the tank can be drained automatically.

6. Heating chamber, the heating chamber is a tube-type scaling, the liquid material passes through the tube, and the material is heated, evaporated and vaporized.

Features of falling film evaporator:

1. The entire system has a reasonable and elegant design, stable operation, high efficiency and energy savings and low steam consumption;

2. The concentration ratio is large, and the falling film evaporation makes the liquid with high viscosity easy to flow and evaporate, and the concentration time is short;

3. The special design can realize switching and changing efficiency through simple operation, so as to adapt to the production of different products;

4. The entire heating system of the equipment has the main characteristics of high heat transfer efficiency and short heating time due to the uniform heating of steam and the liquid film flow evaporation of the material and liquid. If the hot pressure pump is reconfigured, it has the advantages of energy saving and consumption reduction, low steam consumption and low cooling water circulation;

5. Because the material evaporates in a film in each tube, the heating time of the material liquid is very short, so it is very beneficial to the evaporation and concentration of food, and the nutrients of the food are largely preserved;

6. The top of the evaporator is sprayed and fed or passed through multiple overflow film distribution devices to ensure that the material liquid is evenly distributed in the evaporator film tube to form a film shape, which greatly improves the heat transfer coefficient, increases the evaporation rate, and can prevent the phenomenon of "dry wall";

7. The large-scale equipment adopts a vertical floor-standing structure. The whole set of equipment has a compact structure, a small footprint, and a simple and smooth layout, which represents the development of large-scale complete sets of evaporation equipment;

8. Under the action of vacuum, the evaporation process not only guarantees the hygienic requirements of the material, but also ensures the environmental protection requirements, and at the same time greatly reduces the evaporation temperature. With the configuration of a hot pressure pump, part of the secondary steam is re-inhaled by the jet hot pressure pump for first-effect evaporation. Shell side, the heat is fully utilized, and the material liquid is heated mildly, which is suitable for the concentration of heat-sensitive materials;

9. The equipment is suitable for evaporating and concentrating foaming materials. Since the material liquid evaporates into a film in the heating tube, the vapor-liquid separation is formed. All the secondary steam enters the separator to strengthen the separation, and there is not much impact in the whole process of the material and liquid, which avoids the formation of foam.

10. For food evaporation and concentration, the equipment can have sterilization function at the same time, the two processes of sterilization and concentration are completed at one time, and the heating time of the material is short, which is suitable for the concentration of heat-sensitive material and liquid;

11. The equipment can be equipped with a CIP cleaning pipeline, which can realize on-site cleaning. The complete toolkit is easy to operate and has no end.

12. Continuous feeding and discharging, the material liquid can reach the required concentration in one pass through the equipment;

13. The equipment can be equipped with an automatic system to realize automatic control of feeding amount, automatic control of heating temperature, automatic control of discharge concentration, automatic control of cleaning, and can also be equipped with protection measures for sensitive materials in case of sudden power failure and failure. Other security, alarm and other automatic operation and control.

Falling film evaporator advantages and disadvantages:

1. The falling film evaporator has the characteristics of low temperature evaporation: because the inside of the falling film evaporator can maintain a high degree of vacuum, the boiling point of the material to be processed will be greatly reduced, so the falling film evaporator is especially suitable for low temperature evaporation of heat-sensitive materials.

2. The heat transfer coefficient and evaporation intensity of the falling film evaporator are high: when the boiling point of the internal material decreases, the temperature difference with the heat medium becomes larger, and the turbulent liquid film reduces the thermal resistance, while suppressing and improving the wall material. Scaling. The evaporator wall heat transfer coefficient of the falling film evaporator is also improved.

3. The flow time of the falling film evaporator is short: the flow time of the material in the falling film evaporator can be shortened to about 10 seconds. For the more commonly used movable scrapers, the scraper end face has a groove, which is 45 degrees. By changing the bevel angle, the flow time of the material can be changed. By reducing the flow time, the product can be effectively prevented from decomposing, polymerizing or degrading during the evaporation process.

4. The falling film evaporator can operate under vacuum conditions: because the resistance of the vapor from the evaporation surface to the condensation link is very small, and the inner wall of the entire falling film evaporator body can be maintained at a high degree of vacuum, Due to the improvement of vacuum degree, the boiling point of the material to be treated in the falling film evaporator is effectively reduced.

The steps of using the falling film evaporator:

1. Open the feed valve, the material enters the feed tank, when the liquid level reaches the requirement, turn on the feed pump, the electric feed regulating valve adjusts the flow, and the material passes through the preheater and enters the evaporator stably.

2. When the liquid level in the evaporator reaches the requirement, stop feeding, open the circulation pump, open the circulation valve, and establish the circulation (or reflux).

3. Open the raw steam shut-off valve, introduce the steam into the shell side of the evaporator, and start to heat up the materials in the system. When the temperature of the powder separator rises to 60 degrees, turn on the steam compressor and the motor. The initial frequency is set to 5Hz, according to the pressure of the separation chamber. The pressure difference with the inlet of the heating chamber (50KPa), and the current of the steam compressor (90% of the rated current of the motor), slowly increase the frequency (3Hz/time) until the frequency increases to the set value M. During this period, when the inlet temperature of the heating chamber reaches 80-84 degrees, the water supply ball valve of the steam compressor is opened to automatically control the water supply, and the flow rate is the set value N. When the temperature of the separation chamber reaches 84-85 degrees, close the raw steam shut-off valve.

4. When the system reaches the evaporating temperature, the liquid level in the evaporator begins to drop, and when it drops to the liquid level C%, turn on the feed pump, slowly open the feed regulating valve, control the electric regulating valve to adjust the feeding, and maintain the liquid in the evaporator. The position balance is in the range of D%, the system is stable, at this time the system reaches equilibrium and starts to evaporate stably.

Application of falling film evaporators:

The falling mode evaporator is suitable for the concentration of heat-sensitive materials such as fresh milk, fruit juice, soy milk, xylitol, sorbitol, honey, starch sugar, fructose, glucose, traditional Chinese medicine extract. The equipment operates in a vacuum state, the material is evaporated at a low temperature, and the heating time is short, which can keep the original flavor of the material to the greatest extent, and continuously enter and exit the material, easy to operate, maintain and clean, suitable for food, pharmaceutical, chemical, biological, environmental protection, Waste liquid recycling and other industries.

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