Chinese medicine immersion spray dryer

"Spray Dryer for TCM Immersion" is a device specially used to dry TCM extract into powder. It is a very important specific application of pressure spray dryer in the field of TCM pharmacy.

The core function is to quickly transform the viscous liquid (extract) obtained from traditional Chinese medicine extraction, which is difficult to preserve and transport, into a dry powder that is easy to use, preserve, and make into the final dosage form.

Chinese herbal extracts have the following characteristics that make the drying process very difficult:

High viscosity and easy to stick to walls: The paste is very viscous and easily sticks to the inner wall of the drying tower during drying, causing coking, deterioration, and a decrease in yield.

High sugar content and easy to absorb moisture: Many traditional Chinese medicinal materials contain a large amount of sugar, and the dried powder is easily able to absorb moisture from the air, becoming wet and clumping again.

Heat sensitivity: Many active ingredients in traditional Chinese medicine, such as glycosides, volatile oils, alkaloids, etc., are unstable to heat and can decompose and become ineffective at high temperatures.

Complex composition: It contains multiple complex polymer substances and exhibits complex behavior during the drying process.

Therefore, the spray dryer used for Chinese herbal extracts is not an ordinary model, but a specially designed and optimized special equipment.

Its basic principle is the same as that of ordinary pressure spray dryer, but it has been improved according to the characteristics of traditional Chinese medicine extract:

Raw material preparation: The thick paste (usually with a relative density between 1.1 and 1.3) obtained by boiling and concentrating traditional Chinese medicine in water is used as the raw material.

Feeding and atomization:

Use high-pressure pumps (such as screw pumps) to stably deliver thick paste to specially designed atomizers (such as large aperture, anti clogging nozzles).

Under high pressure, the paste is sprayed from the nozzle and atomized into countless tiny droplets.

Hot air contact and drying:

The heated clean hot air (usually controlled at around 150 ℃ -200 ℃, depending on the properties of the paste) is introduced into the drying tower.

The atomized extract droplets mix instantly with hot air, and the water evaporates within a few seconds.

Powder collection and discharge:

The dried traditional Chinese medicine powder falls to the bottom of the tower.

Due to the high hygroscopicity of traditional Chinese medicine powder, the discharge system (such as the rotary discharge valve) must have good sealing and is often connected to the vacuum feeding system or directly connected to the packaging machine to prevent the powder from being exposed to humid air.

Waste gas treatment:

The exhaust gas is recovered through two stages of cyclone separator and bag filter, ensuring efficient collection of fine powder and improving product yield.

Principle of spray dryer for soaking Chinese medicine

1. Feeding and atomization: the pretreated instant tea concentrate or fat powder lotion with stable composition is delivered to the atomization system of the spray dryer by a high-precision feed pump. The system mainly has two methods: pressure atomization and centrifugal atomization. Pressure atomization uses a high-pressure pump to pressurize the material to a certain degree, and then sprays it out at high speed through a specially designed nozzle. Under the action of high pressure and the special structure of the nozzle, the material is dispersed into countless small droplets, with particle sizes typically ranging from tens to hundreds of micrometers. Centrifugal atomization is achieved by using a high-speed rotating atomizing disc to rapidly disperse the material into tiny droplets by throwing it out from the edge of the disc under the action of centrifugal force. These tiny droplets greatly increase the contact area with hot air, laying the foundation for efficient drying processes in the future.

2. Drying process: At the same time, the hot air generated by the heating system enters the drying chamber at a precisely set temperature and flow rate. The temperature of hot air is generally controlled within the range of 80 ℃ -200 ℃ based on the characteristics of the material and product quality requirements. The atomized material droplets are thoroughly mixed with hot air in a drying chamber and undergo heat exchange. Due to the fact that the temperature of hot air is much higher than the boiling point of water in droplets, and there is a significant temperature and humidity difference between the two, the water in droplets quickly absorbs heat from the hot air and evaporates, transforming into water vapor that diffuses into the hot air. As the water evaporates continuously, the instant tea or vegetable fat powder components in the droplets gradually concentrate and solidify, ultimately forming dry powder particles.

3. Separation and collection: The dried powder particles enter the gas-solid separation system together with moist and hot air carrying water vapor. This system usually consists of a cyclone separator and a bag filter. The cyclone separator utilizes centrifugal force to separate most of the powder particles from the airflow and slide down the inner wall of the separator to the collection device at the bottom. The bag filter further captures the fine particles separated by the cyclone separator, ensuring that the exhaust gas contains almost no powder particles, achieving efficient product recovery and meeting environmental emission requirements. The collected powder particles are transported to the subsequent packaging or storage process through the bottom discharge device.

Components of traditional Chinese medicine immersion spray dryer

1. Feeding system: consisting of raw material storage tanks, conveying pumps, and connecting pipelines. The raw material storage tank is made of high-quality stainless steel, which has good corrosion resistance and sealing performance. It can store a certain amount of instant tea concentrate or vegetable fat powder lotion, and ensure its stability in the feeding process. High precision centrifugal pumps or screw pumps are generally used for conveying pumps, which can accurately adjust the feed flow rate according to production needs, ensuring that materials are transported to the atomizer at a constant speed, and avoiding the impact of flow fluctuations on atomization effect and product quality. The smooth inner wall of the connecting pipeline reduces the resistance and wall hanging phenomenon of materials during transportation, ensuring smooth feeding.

2. Atomization system: The nozzle of the pressure atomizer is made of special wear-resistant and corrosion-resistant materials, and its internal structure is carefully designed to evenly disperse the material into small droplets under high pressure, with a relatively narrow droplet size distribution. The atomization disc of a centrifugal atomizer has high rotational speed and good dynamic balance performance, which can adapt to materials of different concentrations and viscosities. By adjusting the rotational speed and structural parameters of the atomization disc, the particle size and distribution of liquid droplets can be flexibly controlled. In addition, the installation and maintenance of the atomizer are convenient, easy to disassemble and clean, to ensure its long-term stable operation.

3. Drying chamber: It is the core place for drying materials, usually adopting a cylindrical or conical structure with spacious interior space to ensure sufficient contact time and space between hot air and atomized droplets. The material of the drying chamber is selected from high temperature resistant and corrosion-resistant stainless steel or special alloy materials, which can withstand the long-term erosion of high temperature hot air and the possible corrosive effects of materials. At the same time, the airflow distribution inside the drying room is carefully designed. By setting up a reasonable hot air distributor and guide plate, the hot air is evenly mixed with the atomized droplets, avoiding local overheating or undercooling, ensuring that instant tea and vegetable fat powder are heated evenly during the drying process, and the effective ingredients are retained.

4. Heating system: Provides the required heat for the drying process, and can be heated using various methods such as electric heating, steam heating, gas heating, etc. The specific choice depends on the energy supply situation and cost considerations at the production site. The heating system is equipped with high-precision temperature sensors and intelligent control systems, which can monitor the temperature of the hot air in real time and automatically adjust the heating power according to the set value, so as to stabilize the temperature of the hot air within a fluctuation range of ± 2 ℃, meeting the strict requirements for temperature stability in the drying process of instant tea and vegetable fat powder. In addition, the heating system also has the characteristics of high efficiency and energy saving. By optimizing the heat exchange structure and control method, energy utilization efficiency can be improved and production costs can be reduced.

5. Gas solid separation system: As a primary separation equipment, the cyclone separator uses centrifugal force to separate most of the larger powder particles from the airflow, and its separation efficiency can usually reach 80% -95%. The bag filter serves as a secondary separation device to further capture the fine particles separated by the cyclone separator, with a filtration accuracy of several microns, ensuring that the exhaust emissions meet environmental standards. The gas-solid separation system has a compact structure, small footprint, and stable and reliable separation effect, which can adapt to the needs of different production scales. At the same time, the system is also equipped with an automatic dust cleaning device, which can regularly clean the bag filter to ensure its long-term efficient operation.

Schematic Diagram of Chinese Medicine Immersion spray Dryer