Spray drying is a method that can complete drying and granulation at the same time. Solutions, emulsions, and suspensions can be directly dried into powder or granular products without evaporation and destruction.
Nowadays, spray drying is widely used for rapid drying of liquid materials and is suitable for pharmaceutical and other fields. According to relevant technical personnel, there are three main methods of spray drying: pressure type, centrifugal type and air flow type.

Pressure Spray Drying
The principle of the pressure spray drying method is to use a high-pressure pump to collect materials through an atomizer (spray gun) to form mist particles, which are in direct contact with hot air for heat exchange, and drying is completed in a short time.

The pressure spray micronization equipment has two guide grooves that rotate the liquid to maximize the turbulence of the solution during spraying. One of the guide groove axes is perpendicular to the nozzle axis and does not intersect with it; the second is that the guide groove axis is at a certain angle with the horizontal plane.

Centrifugal Spray Drying
The principle of the centrifugal spray drying method is to use a disk that rotates at high speed in the horizontal direction to impart centrifugal force to the solution, causing it to be thrown out at high speed to form films, filaments or droplets. Due to the collision, prevention and tearing of the air, the tangential acceleration with the rotation of the disk and the radial acceleration with the centrifugal force cause the disk to move at a combined speed, its orbit is a spiral, and the liquid flows from the disk along this spiral After being thrown, it will disperse into very small droplets, which will move in the tangential direction of the disk at an average speed. A drop of water will fall again due to gravity. Because the sprayed particles are of different sizes, their flight distances will also be different. Particles falling at different distances therefore form a symmetrical cylinder around the center of the axis of rotation.
Technicians said that the way to obtain more uniform droplets using the centrifugal spray drying method is to reduce the feeling when the disk rotates; when the amount of liquid entering the disk remains constant per unit time, the surface of the disk should be smooth and lubricated. In addition, the circular speed of the disc should not be too small.
The centrifugal spray dryer is a drying equipment suitable for drying emulsions, suspensions, pastes, solutions and other liquids. This equipment has fast drying speed, is suitable for drying heat-sensitive materials, can adhere to the color, aroma and taste of the materials, and is easy to operate and control. Suitable for continuous control and production. The product has good relaxation, fluidity and solubility. Now it is widely used in medicine and other fields.

Air Spray Drying
The working principle of the air spray drying method is that the wet material and heated natural air enter the dryer through the conveyor, and the two are fully mixed. Due to the large heat and mass exchange area, evaporation and drying can be achieved in a short time.
It is reported that there are four main methods of air spray dryer. The first is that the air flow dryer operates under negative pressure, and the material does not pass through the fan; the second is air drying, which is operated under positive pressure, and the material passing through the fan has a destructive effect; the third type of air flow dryer is an exhaust gas circulation type; the fourth type of air flow drying It is an enhanced airflow dryer.