Modern dryers have begun to use intermittently operated fixed bed dryers. In the middle of the 19th century, the use of tunnel dryers marked the development of dryers from intermittent operation to continuous operation. The rotary cylinder dryer better achieves the agitation of the granular material, and the drying ability and strength are improved.
Modern dryers have begun to use intermittently operated fixed bed dryers. In the middle of the 19th century, the use of tunnel dryers marked the development of dryers from intermittent operation to continuous operation. The rotary cylinder dryer better achieves the agitation of the granular material, and the drying ability and strength are improved. Some industries have developed continuous operation dryers that meet the requirements of the industry, such as drum dryers in the textile and paper industry.
In the early 20th century, the use of spray dryers in dairy production provided a powerful tool for large-scale drying of liquid materials. Beginning in the 1940s, with the development of fluidization technology, high-strength, high-productivity fluidized bed and airflow dryers appeared one after another. Frozen sublimation, radiation and dielectric dryers offer new means to meet specific requirements. Far infrared and microwave dryers were developed in the 1960s.
The mechanical equipment used for the drying operation "target=_blank> There are many types of mechanical equipment, which can be divided into normal pressure and decompression according to the operating pressure (reduced pressure dryer is also called vacuum dryer). According to the operation method, it can be divided into intermittent type and Continuous. According to the drying medium, it can be divided into air, flue gas or other drying medium. According to the movement (material movement and drying medium flow), it can be divided into cocurrent, countercurrent and crossflow.
According to the operating pressure, the dryer is divided into two types: atmospheric pressure dryer and vacuum dryer. The operation under vacuum can reduce the moisture partial pressure of space and accelerate the drying process, and can reduce the boiling point of the wet water and the drying temperature of the material. Leakage, therefore, the vacuum dryer is suitable for drying heat sensitive, oxidizable, explosive and toxic materials and wet steam needs to be recycled.
Advantage:
1. Well-designed adsorption tower body
2. High performance activated alumina adsorbent
3, good effect silencer
4. Imported pneumatic controller with two characteristics of power and durability
5. Regenerative gas regulating valve that can precisely adjust the flow rate
According to the heating method, the dryer is divided into a convection type, a conduction type, a radiation type, a dielectric type and the like. The convection dryer, also known as the direct dryer, uses a hot drying medium to directly contact the wet material to transfer heat in a convective manner and to carry away the generated steam. The conductive dryer is also called an indirect dryer, which utilizes conduction. The heat is transferred from the heat source to the wet material through the metal partition wall, and the generated wet steam can be removed by vacuum suction, a small amount of purge gas or condensation on the surface of the separately provided low temperature condenser. This type of dryer does not use drying medium, has high thermal efficiency, and the product is not polluted, but the drying capacity is limited by the heat transfer area of ​​the metal wall, the structure is also complicated, and it is often operated under vacuum; the radiant dryer uses various radiations. The electromagnetic wave emitted by a certain wavelength range is selectively absorbed by the surface of the wet material and then converted into heat for drying; the dielectric dryer uses a high-frequency electric field to cause a thermal effect inside the wet material to be dried.
Advantage:
1, using high-performance evaporator, large heat exchange area, small heat transfer temperature difference, evaporator outlet air temperature is more stable
2. High-efficiency gas-water separation structure is adopted, and oil-water separation efficiency is high;
According to the movement mode of wet materials, the dryer can be divided into fixed bed type, agitated type, spray type and combined type; according to the structure, the dryer can be divided into a box dryer, a conveyor dryer, a drum dryer, and a stand. Dryers, mechanical agitating dryers, rotary dryers, fluidized bed dryers, airflow dryers, vibrating dryers, spray dryers, and combined dryers.
Common knowledge of drying equipment: Common pre-drying machines in China have common spray dryers, air dryers, fluidized bed dryers, flash dryers, fluidized bed dryers, such as spray granulation. Flash Dryer Spray Drying Spray drying is one of the most advanced equipment in drying equipment. Three types of atomization in the conventional method: rotary atomization, pressure atomization, and airflow atomization. Rotary atomization characteristics of a large spray drying capacity (up to 200 tons / hour) will be responsible for easy control, operational flexibility, and a wider range of applications. Pressure atomized spray drying is characterized by coarse particles that can be created for future repairs. Since the nozzle holes are small, they are easily clogged and the liquid must be strictly filtered. The nozzle holes are easy to wear and the use of wear resistant materials. There is also a new structure for nozzle pressure called a pressure-flow nozzle. It features nozzle pressure and air gap nozzles in the surrounding environment. The atomization is divided into two phases: the first liquid film pressure nozzle is formed, and the film is the second air atomization, thereby making more small water droplets. The advantages of this type of nozzle: (1) adjust the pressure of the compressed air, can adjust the droplet diameter, easy to operate; (2) produce, high viscosity liquid, it can atomize the droplet fine; 3 if you disable compression Air, the original pressure nozzle can be used. The atomizing airflow of the laboratory and the main plants in the Middle East, its power consumption. The first two liquids that cannot atomize the nozzle use an air atomizable nozzle. High viscosity paste, paste and filter cake materials for three-fluid nozzle atomization. The drier air flow drying technology is mature, if the operational data can be designed directly.
Currently, a large number of drying equipment manufacturers are able to provide this type of equipment.
Fluidized bed dryer fluidized bed dryer spray dryer. The feeding arrangement is divided into a partial fluidized bed dryer agitator and a heat transfer fluidized bed dryer. When unity is easy to use fluidized bed drying, or agglomerated powder material feed more water will flow into the above difficult phenomenon, this time set up the feed mixer to the above situation, eliminating bundle problems to achieve normal flow. The latter is a combination of heat transfer and convective heat transfer, when the amount of hot air flowing normally is not enough in the country to meet the required heat drying use of the heat exchanger, supply part or most of the heat, what type Operation can save a lot of energy. Take many forms of heat exchangers. Fluidized bed drying is also often used in combination with dry secondary education and higher education. The implementation of the ordinary vibrating fluidized bed said that the vibrating fluidized bed. There are two types of vibrating vibration sources that can be divided into two types: one is a vibration motor drive, and the other is an ordinary motor that generates vibration through an excitation box to make a spring. When vibrating, the size of the bed, the latter is better. In the process of fluidized bed spray granulation dryer, fluidization technology, atomization technology and dry organic combination are three. It is the seed that will atomize the spray liquid into the fluidized bed, so the seeds continue to grow and dry to reach the desired size, the time beyond the catapult. The device's small and large production capacity creates large particles. The industrial application of this device has been increasing.
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