In the spray dryer operation, drying with hot air enters the tower temperature (air temperature) and the outlet temperature (exhaust temperature) decision is very important. Air exhaust temperature and the moisture content of the product, the product should be allowed to determine the water. Hot air temperature is higher, the efficiency is higher, and the economy is better. But the high temperature of the hot air will cause the deterioration of the quality of the product, so the hot air temperature must be in the premise of ensuring the quality of products to improve.  

The hot air temperature of the spray dryer will obviously affect the density of the products. Hot air has a tendency to produce low loose density, which is due to the rapid drying of the hot air, so that the particle surface hardening and residual moisture expansion, and promote the formation of hollow particles. If requirements of high bulk density (low volume), or solid particles, design should not use high temperature air and the formation of a new droplet contact. In the drying of chemicals, hot air temperature up to 538 degrees, the product particle size. It can be found that there is enough pressure to blow the outer surface into an empty hole. In the spray drying of food, the hot air temperature is generally not more than 177 degrees Celsius, so the formation of hollow particles of the initial diameter is not as large as chemical drugs.  

Spray dryer air inlet temperature will directly affect the evaporation intensity of the drying chamber. For non thermal sensitive material, using high temperature air as may be, in order to increase the intensity of evaporation.