Overview of spray dryer for Chinese herbal extract
Chinese herbal extract is extracted from plant roots, stems, and leaves, especially through alcohol extraction process. It has a high sugar content and is prone to softening and melting at high temperatures. ZLPG-5 centrifugal spray dryer for Chinese herbal extracts is especially suitable for drying thermosensitive materials. The final product obtained by drying with this dryer has good uniformity, fluidity, solubility, high purity, and good quality. The production process is simple, and the operation and control are easy. Liquids with a moisture content of 40-60% (special materials, with a content of over 90%) can be dried into powder or granular products in one go. After drying, there is no need for crushing and sorting, reducing the production process and improving product purity. By changing the operating conditions within a certain range, the particle size, looseness, and moisture content of the product can be adjusted. It is very convenient to control and manage.
In the case of high-speed drying, the surface area of the material will greatly increase after spraying in liquid form. In hot air flow, 95% to 98% of water can evaporate instantly. The drying process only takes a few seconds to complete.

Working Principle of spray Dryer for Chinese Herbal Extract
The spray dryer is a drying process that disperses the raw liquid into droplets with an atomizer, and obtains powdered products by directly contacting the droplets with hot air (or other gases). The raw material liquid can be a solution, emulsion, or suspension, as well as a melt or paste. Dried products can be made into powder, granules, hollow spheres, or pellets as needed.
Spray dryer is the most widely used process in liquid forming process and drying industry. It is applicable to spray the slurry in the form of solution, emulsion, suspension, etc. into small droplets in hot air. The spray of the slurry is accelerated and split atomized by the centrifugal force and gravity generated by the high-speed centrifugal rotary table. The atomized droplets are uniformly mixed with the drying medium (hot air) during the falling process, and undergo heat and mass exchange to vaporize and evaporate the moisture in the material. The spray dryer has the advantages of stable product properties, low denaturation, continuity, automation, and great operational flexibility.

The spray dryer for Chinese herbal extracts is a hot air circulation, parallel flow and centrifugal spray dryer. The dry medium air is filtered through primary and intermediate air filters, heated by a heater, and enters the top air distributor of the dryer. The hot air enters the drying chamber uniformly in a spiral shape. The liquid materials are transported to the high-speed centrifugal atomizer at the top of the tower body through the feed liquid pump. Under the centrifugal force, the spray becomes a very fine atomized liquid drop, which flows in parallel with the hot air and can be dried into finished products in a very short time. The finished product is continuously collected by the bottom of the drying tower and the cyclone separator, and the exhaust gas is discharged by the induced draft fan after dust removal.

Process Flow Diagram of spray Dryer for Chinese Herbal Extract

The design of spray drying unit for Chinese herbal extracts has been improved
1. The tower diameter and height have been adjusted accordingly to ensure that the material does not come into contact with the tower wall before drying, and to ensure the residence time of the material in the hot air; The tower wall is equipped with a jacket cold air cooling device to ensure that the material is adsorbed on the tower wall and may soften, melt, or even coke due to local high temperatures; The cone angle increases, and an air shock absorber is installed on the cone. The compressed air pulse seismic cylinder is used to smoothly shoot down the powder adsorbed on the cylinder;
2. All parts of the host that come into contact with materials use flat or curved transitions, and the contact surfaces are polished and polished (precision polishing to 10 or more) to avoid sand holes and blind spots. Eliminate material accumulation and blockage; The entire unit and material contact area are made of stainless steel to ensure that the materials are not contaminated; The transmission components in contact with the material are well sealed, which can prevent water and oil; Use sealed butterfly valves at the discharge area to prevent air leakage; The induced draft discharge pipe section adopts flexible connections, which can be disassembled, cleaned, disinfected, sterilized, etc. at any time;
3. The air pretreatment system adopts air filtration for middle and high school students, purifying the air to a level of 100000;
4. The feeding system adopts a unique freezing and dehumidification feeding method, effectively solving the problems of product agglomeration, softening, and moisture absorption;
5. The elbow from the main drying tower to the cyclone separator is made of one-time formed 304 stainless steel smooth pipeline to prevent material accumulation, and is connected by clamp quick opening method for easy sewage discharge during cleaning;
6. This unit uses PLC program to control the system circuit; The touch screen animation display process is operable, and variable operating parameters are automatically tracked and adjusted using fuzzy technology; Stabilize and safely adjust the atomizer with a frequency converter; Digital display of inlet and outlet air temperature, tower pressure, which can be set, etc.