Powder spray drying is a widely used instrument in the liquid process forming and drying industry. It is suitable for the production of powdered and granular solid products from solutions, emulsions, suspensions and pasty liquid raw materials. Spray drying is an ideal instrument when the particle size distribution, residual moisture content, bulk density and particle shape of the finished product must meet the required standards.
The process of spray drying of milk powder:
The spray drying process is: the material is pumped into the spray dryer, and the atomizer disperses it into small droplets; the air is heated and sent into the drying chamber to mix and contact the material; after the drying process is completed, the dried product is separated. Stored in storage or put into use directly. The milk powder produced by the spray drying method is a uniform powder product, which can be directly packaged as a finished product without drying, pulverizing and other processes, so that the production process of the milk powder is mechanized, continuous and large-scale. The temperature will not be too high to improve the quality of milk powder products, so spray dryers play a huge role in the industrial production of milk powder.
The principle of the milk powder centrifugal spray dryer is that the air is filtered and heated, and enters the air distributor at the top of the dryer, and the hot air enters the drying chamber evenly in a spiral shape. The feed liquid passes through the high-speed centrifugal atomizer at the top of the tower body, and is sprayed (rotating) into extremely fine mist-like liquid droplets, which are in co-current contact with hot air, and can be dried into finished products in a very short time. The finished product is continuously output from the bottom of the drying tower and the cyclone separator, and the exhaust gas is evacuated by the fan.
1. The drying speed is fast. After the material liquid is atomized, the surface area is significantly increased. When contacted with hot air, 95%-98% of its water can be evaporated instantly. The spray dryer for milk powder time of milk only takes a few seconds. Therefore, the centrifugal spray dryer Especially suitable for milk powder production.
2. The spray-dried product has good uniformity, fluidity and solubility, high purity of powder or granule, and excellent quality.
3. The production process is simple, the operation is convenient, and the control is easy. For liquids with a water content of 40%-60% (special materials can reach 90%), it can be spray-dried into powder or granules at one time. After drying, there is no need to pulverize and sieve, which reduces the milk production process and improves the purity of milk powder.
4. By changing the operating conditions of the centrifugal spray dryer, the particle size, bulk density and moisture of the spray-dried product can be adjusted, and the control and management are very convenient.
1. The atomized droplets are generally 10-200um, the surface area is very large, and the residence time is short (20-30s).
2. The temperature of the droplets is close to the wet bulb temperature of the high-temperature air used, so that the dry product has better quality assurance. 3. 3. It is not easy to occur protein changes, vitamin loss, oxidation, decomposition and other phenomena, so it is especially suitable For drying of heat-sensitive materials.
4. The particle size and bulk density of the product can be adjusted arbitrarily, and the product has good fluidity, dispersibility and solubility.
5. The production process is simple, the operation and control are convenient, the labor intensity is low, and it is easy to realize continuous production, large-scale equipment, and easy operation.
6. It can achieve automatic control, and can combine cooling and air supply technology to form a joint production line in the subsequent processing of products.
7. Spray dryer for milk powder is basically carried out in a closed system, which avoids dust flying. For some materials that produce toxic gas and odor, a closed-circuit circulation device can be used to prevent air pollution and improve the production environment.
8. It is easy to meet the GMP standard.
9. No pollution.
10. Our equipment has less material requirements, relatively large disposal capacity, strong anti-overload capability, and low fuel consumption, which can directly reduce your cost.
Points to note:
1. Contact between hot air flow and mist droplets: When a sufficient amount of hot air flow enters the spray drying chamber, the direction and angle of the hot air flow must be considered, whether it is co-current, counter-current or mixed flow, to ensure sufficient contact with the mist droplets before proceeding. adequate heat exchange.
2. Atomization: The atomization system of the spray dryer must ensure that the droplet size distribution is even, which is crucial. Because this can ensure the qualified rate of product quality.
Spray drying is a high-energy-consumption process. Due to the high quality requirements of the dried product and the fact that the moisture content cannot fluctuate greatly, it is required to strictly control the drying temperature and other operating parameters. Therefore, the correct selection and operation of the spray dryer and the control system The rational design of the product is very important to ensure product quality, energy saving and consumption reduction. It not only makes due contributions to promoting and promoting the scientific and technological progress and development of the dairy industry, but also drives and promotes the scientific and technological progress and development of other industries.