Spray dryer application advantages and disadvantages
We are a Chinese distributor of laboratory spray drying equipment. We have spray dryer machine and small spray dryers. They have fast drying speed, simple production process, convenient operation and control, and easy automation.
Application of spray drying:
Spray drying is the fastest growing and most widely used type in important chemical unit operations. The extensive application of spray drying technology in the fields of food, pharmacy, nanomaterials, soil oil pollution bioremediation and environmental protection is reviewed.
Working principle of spray dryer:
Hot air is introduced at the top of the drying tower, and the material liquid is sent to the top of the tower at the same time, and sprayed into mist-like droplets through the atomizer. The surface area of these droplets is large. After contact with the high-temperature hot air, the water evaporates quickly, in a very short time The inside becomes a dry product. After the hot air is discharged from the bottom of the drying tower and the droplets come into contact with it, the temperature will be significantly reduced and the humidity will increase.
Advantages of spray drying:
1. As long as the drying conditions remain constant, the characteristics of the dried product will remain constant.
2. The spray drying operation is continuous, and the system can be fully automatic control operation.
3. The spray drying system is suitable for the drying of heat-sensitive and non-heat-sensitive materials, as well as the drying of aqueous and organic solvent materials.
4. The raw material liquid can be solution, slurry, emulsion, paste or melt, and even filter cake can be processed.
5. The spray drying operation has great flexibility. The spraying capacity is several kilograms to 200 tons per hour.
Disadvantages of spray drying:
1. The investment cost is relatively high.
2. Spray drying is a convection dryer, and its thermal efficiency is relatively low, generally 30% to 40%.
Mechanical principle:
The spray dryer is a thermal process in which liquid materials are atomized into fine mist droplets through nozzles, which are contacted with heat medium in the drying tower and dried into powder. The feed can be a solution, suspension or paste. Atomization can be achieved through a rotary atomizer, pressure atomization nozzle and airflow atomization nozzle. The operating conditions and the design of the drying equipment can be based on the drying required for the product Features and selection of powder specifications.
The spray dryer is the fastest growing and most widely used form in the drying field. It is suitable for liquid materials such as solutions, emulsions and pumpable suspensions to generate powder, granular or block solid products. The different drying characteristics of the material to be dried, such as heat sensitivity, viscosity, and fluidity, and the different quality requirements of the product's particle size, particle size distribution, residual moisture content, bulk density, particle shape, etc., determine the use of different atomizers and airflows. Movement mode and structure of the drying room.
The ball-milled slurry is further stirred evenly in the stirring tank and heated to above 35°C, and then pressure is applied to the stirring tank. Under the action of the pressure, the slurry is sent to the atomizer, and the atomizer is atomized. After chemicalization, spray into the tower from the lower part of the tower. The N2 heated by the oil-air heat exchanger is sent to the gas distributor on the top of the tower by the blower. After passing through the gas distributor, the N2 enters the tower evenly and in a cyclone shape to dry and granulate the atomized slurry. After the pellets are in contact with the hot gas, the liquid on the surface quickly evaporates, and the gas inside migrates to the surface and is taken away by the hot gas during the subsequent drying process. The dried pellets fall to the bottom of the tower and are recycled through a pair of butterfly valves.
