Spray Drying Methods And Comparison Of Advantages And Disadvantages

There are many types of drying granulators, but spray drying granulators are widely used.

The Spray Dryer is designed after digestion, absorption and improvement based on the introduction of foreign products of the same type in the 1980s. Because spray dryers are easy to operate, superior in performance, and excellent in manufacturing, they are especially popular among users in the pharmaceutical and food industries because they can meet GMP requirements in the pharmaceutical and food industries. This equipment is especially suitable for drying and granulating Chinese and Western medicines and foods. The prepared granules have strong disintegration, good fluidity and good instant dissolution, and can be directly used for tablet pressing, capsule filling, granulation and solid beverages, etc.

Spray drying is still widely used in chemical, light industry, food and other industries because of its special advantage that it can directly obtain powdery products with uniform ingredients from a solution or suspension system. The dye industry is widely used in the chemical industry. After the efforts of the majority of engineers and technicians in recent years, the spray drying technology has become more mature, and there are also successful calculation methods for determining the tower size.

Spray drying refers to the process of atomizing the liquid to be dried into tiny droplets through an atomizer in the drying room, and directly contacting and mixing with the hot gas of the drying medium to evaporate water, and then collecting through gas-solid separation to obtain powder or granular products. method.

The raw material liquid may be a solution, an emulsion, or a suspension, or a molten liquid or a paste. The drying medium can be air, nitrogen or superheated steam.

The composition of the spray drying system mainly includes: air heating system, raw material liquid conveying system, atomizer, drying system, gas-solid separation and collection system, control system, medium circulation mechanism with special requirements, etc.

Spray drying is a method of applying systematic technology to material drying. After the thinner is atomized in the drying chamber, in contact with the hot air, the moisture rapidly vaporizes to obtain a dry product. This method can directly dry the solution and emulsion into powder or granular products, and can save the steps of evaporation and pulverization. Through mechanical action, the material to be dried is dispersed into very fine mist-like particles (to increase the evaporation area of water and accelerate the drying process) and contact with hot air to remove most of the water in an instant to make the solid in the material The substance dries into a powder.

Spray drying has the characteristics of fast heat transfer, rapid moisture evaporation, and short drying time, and the product quality is good, the texture is crisp, and the dissolution performance is good. It can improve the dissolution rate of some preparations and is suitable for heat sensitivity. In addition, spray drying can also be used To prepare microcapsules.

Spray drying is a widely used method for dye drying. A drying method that atomizes dyes to remove moisture. Suitable for drying all kinds of dyes. It can dry dye powder, superfine powder, dust-free powder and hollow granule. According to the dye atomization method, it can be divided into three categories: (1) Airflow atomization, which uses compressed air or water vapor to atomize the material liquid; (2) Pressure atomization, which uses a high-pressure pump to push the material liquid out of the nozzle at high speed , Forming a mist; (3) Rotary atomization, the material liquid is added to the high-speed spinning disc (7000 ~ 28000r/min) in the atomizer, and the material liquid is quickly thrown out and atomized. The third method has good effect, short time and high labor productivity, and is favored by the dye industry. Its disadvantage is that the equipment investment is large and the energy consumption is high.

advantage

1. The drying process is very fast.

2. It can be directly dried into powder.

3. Easy to change drying conditions and adjust product quality standards.

4. Due to instantaneous evaporation, the equipment material selection requirements are not strict.

5. There is a certain negative pressure in the drying room, which ensures the sanitary conditions during production, prevents dust from flying in the workshop, and improves product purity.

6. High production efficiency and few operators.

7. Large production capacity and high product quality. The spray volume per hour can reach several hundred tons, which is one of the larger dryers.

8. The spray Dryer is easy to adjust, and the operating conditions can be changed in a larger range to control the quality indicators of the product, such as particle size distribution, moisture content, biological activity, solubility, color, fragrance, taste, etc. [1]

shortcoming

1. The equipment is more complex, covers a large area, and requires a large investment at one time.

2. Atomizer and powder recovery device are more expensive.

3. A large amount of air is needed to increase the power consumption of the blower and the capacity of the recovery device.

4. The thermal efficiency is not high and the heat consumption is large.