Spray drying equipment primarily involves introducing hot air at the top of a drying tower. The liquid material to be dried is delivered to the top of the tower and atomized into mist droplets by an atomizer. These droplets rapidly evaporate upon contact with the high-temperature hot air, resulting in a very short drying time. This not only facilitates better drying of materials but also promotes the recovery and utilization of particulate matter carried in the exhaust gas, improving material utilization efficiency.
Currently, spray drying has become a rapidly developing and widely used method in the drying field. It not only dries a wide range of products but also is very simple to operate, enabling automated processing. Different atomizers and airflow patterns are determined by the different drying characteristics of the material, such as its heat sensitivity and viscosity, as well as the size and particle size distribution of the product, providing greater convenience for operators.
A spray drying tower is a thermal process in which liquid materials are atomized into fine mist droplets through nozzles, and then dried into powder upon contact with a hot medium inside the drying tower. The feed can be a solution, suspension, or paste. Atomization can be achieved through rotary atomizers, pressure atomizing nozzles, and airflow atomizing nozzles. Operating conditions and the design of the drying equipment can be selected based on the required drying characteristics and particle size of the product. To meet market demands and improve product solubility, reconstitution, and packaging performance, some spray drying towers incorporate granulation equipment. However, this increases the risk of thermal denaturation and loss of aromatic substances. Spray drying towers effectively solve the problem of integrating the spray drying tower, separation chamber, and cooling chamber. During the falling-rate drying stage of spray drying, the powder temperature rises as the moisture content decreases.
Clean air, after being heated, enters the spray drying tower. Inside the tower, various liquid materials are atomized into tiny droplets using two-fluid (or three-fluid) nozzles. These droplets rapidly exchange with the hot air, evaporating the water (or solvent) in the liquid material, which is then discharged with the hot air, resulting in a powdered or granular product.
1. Particularly effective for highly viscous, paste-like, and slurry-like materials; other equipment cannot replace it.
2. Experimental models with a wide variety of products; widely applicable low-temperature drying.
3. Spray drying tower nozzles have a simple structure, are easy to maintain, and have low operating costs.
