Features of folding structure
Pressure spray drying is mainly determined by the working principle of the pressure atomizer, which gives this drying system its own characteristics. Since the product obtained by pressure spray drying is in particulate form, the particle size of both the droplets and the product are larger than the other two types, resulting in a longer drying time for the droplets. In addition, the sprayed atomization angle is also small, generally between 20° and 70°, so the shape of the dryer is mainly high tower shape, so that the droplets can have enough residence time. The feed liquid applies a certain pressure and is atomized by the atomizer, so a high-pressure pump is required in the system. In addition, because the aperture of the atomizer is small, to prevent debris from blocking the atomizer channel, it is necessary to filter the material before entering the high-pressure pump. Pressure spray drying is used to obtain granular products.
Folding atomization characteristics
There are also three mechanisms for droplet formation and splitting of pressure nozzles (droplet, filament, and film). However, the pressure nozzles used in industrial production are usually operated under membrane (hollow cone) splitting conditions. The thickness of the liquid film formed by the pressure nozzle is approximately 0.5~4μm. In industrial spray granulators, it is difficult to directly see the length of the liquid film during nozzle operation. Because of the high jet speed and turbulence caused by the low viscosity liquid during atomization, the liquid film produced is very short. When the viscosity is increased, the liquid film becomes longer; when the surface tension is increased, the liquid film becomes shorter. The internal structure of the pressure nozzle should be able to split the liquid with minimal external disturbance during the process of forming a cone-shaped film.