Temperature environment application of various materials in centrifugal spray dryer

The centrifugal spray dryer adopts high-speed centrifugal disc atomization to atomize the material into mist droplets, and simultaneously exchange heat with the hot air specially distributed into the tower body in a coordinated movement trajectory in a very short time. The water is evaporated to form a uniform powdery dry product. Centrifugal spray dryers are widely used in the drying of chemical, food, pharmaceutical, petrochemical, light industry, pesticide and other industries.

The centrifugal spray dryer has a fast drying speed, and the surface area of ​​the liquid is greatly increased after atomization. In the hot air flow, 95%-98% of the water can be evaporated instantaneously, and the drying time is only a few seconds, which is especially suitable for the drying of heat sensitive materials. . The product has good uniformity, fluidity and solubility, and the product has high purity and good quality. The production process is simplified and the operation control is convenient. For liquids with a moisture content of 40-60% (up to 90% of special materials), the products can be dried into powdered products at one time. After drying, no pulverization and screening are required, which reduces the production process and improves the purity of the products. The particle size, bulk density and moisture of the product can be adjusted within a certain range by changing the operating conditions, and the control and management are very convenient.

The spray drying process is completely dependent on the product of the composition. Some are very easy and others are very difficult to dry.

The total moisture content of the vented air is one of the most important parameters. Depending on the product of the composition, for example, the total moisture content in the venting air is high, the dry product has a high protein content, and the high carbohydrate content requires a low moisture content to avoid sticking to the chamber, pipes and cyclones. powder.

This is also why the total moisture content in the surrounding air is an important parameter, knowing the design of the former plant, as a reduction in the total moisture of the surrounding environment is high "drying potential".

Another important parameter known is the maximum solids content in the concentrate. This is viscosity driven and therefore also depends on the product of the composition. As a rule of thumb, the following applies:

High fat content: allows for higher solids content. A lower drying temperature is required to avoid sticking (ie, the total moisture content in the exhaust gas being exhausted is low).

High protein content: requires a lower solids content due to viscosity (except hydrolyzed protein). Allow higher drying temperatures to be non-stick (ie, exhaust gas with a high total moisture content). The protein content is higher and it is more difficult to become an agglomeration process.

High Carbohydrate Content: A concentrate that allows for a higher solids content (except starch, due to its high viscosity). Allow higher spray drying temperatures to be non-stick, if high molecular weight types of carbohydrates (eg, maltodextrin and starch), this can result in an increase in glass transition temperature. The moisture content in the air discharged from the chamber can be higher when the powder is dried, having a higher glass transition temperature and thus being more economically dry.

If the carbohydrate is of low molecular weight type (eg sugar, lactose and glucose syrup), it will result in a glass transition temperature, which requires a lower spray drying temperature to avoid sticking (ie reducing the discharge at lower total moisture content) air).