Spray Drying In Downstream Processing
A spray dryer is a dryer for processing solutions, suspensions, or slurry-like materials. Therefore, spray drying is most used in downstream processing. The spray dryer uses a spraying method to make the materials into mist droplets and disperse in the hot airflow. The materials and the hot air contact each other in the form of current, countercurrent, or mixed flow so that the moisture quickly evaporates to achieve the purpose of drying. There are numerous examples of spray drying in downstream processing such as spray drying of food, ceramics, and pharmaceuticals.
Using this drying method, operations like concentration or filtration can be omitted, granular products with small grain size can be obtained, and the drying time is extremely short, generally 5-30s. Spray drying in downstream processing contains the drying processing of highly heat-sensitive materials and materials that are easily decomposed during the concentration of the material liquid, and this drying method fits these materials well since it can keep their physical or chemical properties.
Spray drying in downstream processing usually requires for industrial spray dryer or spray drying machine of which the speed is over 150L/h. Therefore, spray dryers used should meet the requirements of the environmental protection laws. Using a cyclone alone to separate the product and purify the exhaust gas is not enough for spray drying in downstream processing. Generally, a bag-type dust collector is also used to purify the dust in the exhaust gas to make the amount of gas less than 50 (standard state), or a wet scrubber can be used to reduce the dust content.
One example of spray drying in downstream processing is the processing of ceramics. Ceramic raw material processing
technology and equipment has not been a breakthrough for many years. But things have changed nowadays with the help of spray dryers. In the production process of the powder, the spray dryer realizes an unmanned monitoring system, which can analyze the factors that cause the real-time changes of the key data (inlet and outlet air temperature, air volume, mud pressure, and moisture in the spray dryer) through the processing software. It can also simulate the manual operation to adjust the temperature of the hot blast stove, the flow rate of slurry, etc. Spray drying in downstream processing is undoubtedly an honor of mankind.
In the past two years, fuels used for the spray drying in downstream processing have also improved. Instead of original oil, people began to use coal water slurry to meet their needs. The conversion from original oil burning to the use of coal water slurry as clean energy has not only saved fuel costs but also reduced atmospheric pollution. Spray dryer is one of the main equipment of downstream processing. The energy consumption of the drying link accounts for a large proportion of the total energy consumption of the production line. Using coal water slurry can reduce the cost by 20% compared with oil burning. And it also leads spray drying in downstream processing to a more environmental-friendly direction.