Inexpensive Low Temperature Spray Dryer
Centrifugal spray dryer is a kind of spray dryer. It uses a high-speed centrifugal atomizer to atomize the material liquid, and makes the material liquid in the form of extremely small droplets after atomization and hot air at a predetermined temperature. Fully contact, complete the dehydration and drying of the material in a very short time, and finally collect the complete set of drying equipment by the powder collecting device. Compared with pressure cheap spray dryer, centrifugal spray dryers are more adaptable to materials, and can spray dry high-concentration and high-viscosity materials, and have greater adjustability than pressure spray dryers. , chemical industry and other industries are widely used. According to the form of atomization, spray dryers can be mainly divided into centrifugal low temperature spray dryer and pressure spray dryers (air-flow spray dryers are rarely used today, and will not be introduced for the time being). The centrifugal type uses a high-speed centrifugal atomizer to throw the material and liquid along the tangential line of the atomizing disc at a very high speed. At a high speed of 12000-25000rps, the material liquid is instantly silken into extremely fine droplets. The pressure spray adopts a high-pressure nozzle, and the liquid is pumped into the nozzle by a high-pressure pump, and the liquid is sprayed out in a straight line, and is atomized in the process. The two types of spray dryers have different structures due to their different atomization principles. The centrifugal spray dryer has a larger diameter of the main tower because the material is thrown out horizontally. The high pressure of the liquid is sprayed downward (also designed as a bottom spray type), so the diameter of the main tower is not large, but the height is high. Both are widely used in the manufacturing industries of food, chemical industry and Chinese patent medicine, and are irreplaceable for equipment.
The working principle of centrifugal spray dryer:
The normal temperature air is filtered and heated, and is introduced into the hot air distributor at the top of the centrifugal cheap spray dryer by the induced draft fan, and the hot air enters the drying tower evenly in a spiral shape. The feed liquid passes through the high-speed centrifugal atomizer at the top of the tower, and is (rotated) sprayed into extremely fine mist-like liquid droplets, which are dried into granular powder in a very short period of time in co-current contact with hot air. The finished material is continuously discharged from the bottom of the drying tower and the cyclone, and the tail gas is evacuated by the induced draft fan. Centrifugal spray dryer is a complete set of drying system. In terms of function, it is mainly composed of five parts: liquid supply system, hot air system, atomization system, material receiving system and control system.
Liquid supply system: pump the liquid into the centrifugal atomizer, mainly the liquid supply pump and the liquid supply pipeline. The liquid supply pump needs to be selected according to the material characteristics, and the conventional ones are peristaltic pump, screw pump, etc.
Hot air system: The hot air system consists of a heat source and wind equipment. According to the actual situation, the heat source equipment can choose three types: electric heating, steam radiator electric heating compensation, and natural gas hot blast stove. The wind power equipment includes a blower and an induced draft fan. The blower is connected through a pipeline before the heat source equipment is installed, and the induced draft fan is installed after the receiving system, and then connected to the flue pipe for exhaust emission. In addition, the hot air distributor designed in the main tower is also included.
Atomization system: mainly refers to the atomizer, the conventional ones are electric centrifugal atomizer and mechanical centrifugal atomizer.
Material collection system: The material collection of the low temperature spray dryer mainly refers to the separation of water vapor, air and powdered materials and then collection of finished products. The separation equipment includes cyclone separator, bag filter, and water film filter. In the conventional design, there are four combinations of single cyclone, cyclone + bag filter, cyclone + water film filter, cyclone + bag filter + water film filter, which need to be based on material characteristics, environmental protection The requirements and equipment investment costs are comprehensively considered.
Control system: unified control of the entire centrifugal spray drying system, mainly including feed control, temperature control, air volume control and other parts. It can be designed as a button control or a PLC integrated circuit control.
Features of centrifugal spray dryer:
1. The drying speed is fast, and the surface area of the material liquid is greatly increased after atomization. In the hot air flow, 95%-98% of the water can be evaporated instantly, and the drying time is only a few seconds. It is especially suitable for drying heat-sensitive materials.
2. The product has good uniformity, fluidity and solubility, high product purity and good quality.
3. The production process is simplified and the operation control is convenient. For the material liquid with a moisture content of 20-90% (mass ratio), it can be dried into powder and granular products at one time. After cheap spray dryer, it does not need to be pulverized and screened, which reduces the production process and improves the product purity. The particle size, bulk density and water content of the product can be adjusted by changing the operating conditions within a certain range, and the control and management are very convenient.
The centrifugal spray dryer is suitable for materials:
Chemical industry: magnesium oxide, white carbon black, dye intermediates, new energy lithium iron phosphate, catalysts, sulfuric acid agents, amino acids, white carbon black, etc.
Plastic resin: AB, ABS emulsion, urea-formaldehyde resin, phenolic resin, glue (urea) formaldehyde resin, polyethylene, polyvinyl chloride, etc.
Food industry: fat-rich milk powder, gluten, cocoa milk powder, milk replacer powder, hunting blood powder, egg white (yellow), etc.
Food and plants: oats, chicken juice, coffee, instant tea, seasoning meat, protein, soybean, peanut protein, hydrolyzate, etc.
Sugars: corn steep liquor, corn starch, glucose, pectin, maltose, potassium sorbate, etc.
Ceramics: alumina, tile materials, talc, etc.
There are many types of materials suitable for centrifugal low temperature spray dryer, and it is impossible to list them one by one. However, according to experience, most liquid materials can be sprayed into powder and granular products at one time by using centrifugal spray dryers.
