Fine atomizing spray, chemical fiber spinneret, spinneret

Drying principle of HNA spraying equipment


2022-11-23 14:59

Spray drying requires that materials and liquids be dispersed into very small droplets, so that material liquids can form a large specific surface area, so that droplets and hot air will generate significant heat and mass exchange, thus rapidly eliminating moisture in materials for a few seconds to dozens of seconds. Then dry. Spray drying is to use different spray to spray suspension or viscous liquid into mist, and heat and mass transfer occurs between hot air and drying process. The finished product is sunk into the bottom of the drying chamber in the form of powder and discharged continuously or intermittently from the unloader.

Low drying temperature. Although hot air with higher temperature is used, due to the large amount of water contained in the droplet, generally 5o to 60oC, the surface temperature is not higher than the wet bulb temperature of the heating air, and the residence time of the material in the dryer is very short. The final temperature is not too high and is very suitable for drying heat sensitive materials.

The product has good dispersibility and solubility, and the purity of the finished product is high. However, the volume and drying intensity of spray drying are small, the volume of drying chamber is large, and the heat consumption is large. Generally, it takes about 6000 kilojoules of heat to evaporate 1 kg of water, which is equivalent to consuming 2.5 to 3.5 kg of steam.

The key of spray drying is the atomization of feed liquid, which is related to the technical and economic indicators of spray drying and product quality. The ideal spray needs uniform spray particles, which have simple structure, large output and low energy consumption.

There are three kinds of atomizers: pressure spray, air spray and centrifugal spray. Forming pressure spray drying tower, air spray drying tower and centrifugal spray drying tower spray drying equipment. In the bio industry, two types of spray drying equipment are used more frequently.