A set of perfect function of the spray drying device, should be composed of which several systems? What are their roles? What are the main equipment included in each system?

Spray drying with fast heat transfer, rapid evaporation of water, drying time is instantaneous, and the product quality is good, crisp texture, solubility performance is also good, can improve the dissolution rate of some preparations for heat-sensitive drugs, in addition, spray drying can also be used for the preparation of microcapsules.　Dye drying widely used method. The drying method of removing water by atomizing the dye. Applicable to the drying of various types of dyes. Can dry dye fine powder, ultra-fine powder, dust-free powder and hollow granules. According to the way of dye atomization can be divided into three categories: (1) airflow type atomization, using compressed air or water vapor to make the material liquid atomized; (2) pressure type atomization, using a high pressure pump to press the material liquid from the nozzle at high speed to form a mist; (3) rotary type atomization, using the material liquid is added to the high speed rotating dumping plate (7000~20000r/min) inside the atomizer to dump the material liquid quickly and atomize it. The third method has good effect, short time and high labor productivity, which is favored by the dyestuff industry, but its disadvantage is large investment in equipment and high energy consumption. Spray drying principle Through mechanical action, the material to be dried, dispersed into very fine particles like fog, (increasing the area of water evaporation, accelerating the drying process) and hot air contact, most of the water will be removed in an instant, so that the solid material in the material is dried into powder. Advantages and disadvantages of spray drying advantages and disadvantages of spray drying 1. drying process is very rapid; 2. can be dried directly into powder; 3. easy to change the drying conditions, adjust the product quality standards; 4. due to instantaneous evaporation, the choice of equipment and materials is not strict; 5. drying room has a certain negative pressure, to ensure that the production of hygienic conditions, to avoid dust flying in the workshop, to improve the purity of the product; 6. high production efficiency, operator Fewer operators. Disadvantages of spray drying 1. equipment is more complex, covers a large area, a large investment; 2. atomizer, powder recovery device price is higher; 3. need more air, increase the blower's power consumption and the capacity of the recovery device; 4. thermal efficiency is not high, heat consumption. Spray drying on the equipment requirements 1. and product contact parts, must be easy to clean sterilization; 2. should be prevented from scorching powder measures to prevent hot air vortex and countercurrent; 3. to prevent the air from carrying impurities into the product; 4. configure the temperature, pressure indication recorder device, easy to check the production operation; 5. with a high recovery rate of the dust recycling device; 6. should be quickly out of the powder cooling, in order to improve the solubility, Quick solubility; 7. Drying room temperature and exhaust air temperature, not allowed to exceed 100 ℃, to ensure safety and quality; 8. Spray thick milk droplets and hot air uniform contact, improve thermal efficiency; 9. Viscosity of the material to minimize the phenomenon of sticking to the wall. Classification of spray drying equipment according to the classification of particulate method (1) pressure spray drying method: ① Principle: the use of high-pressure pumps, to 70 ~ 200 atmospheric pressure, the material through the atomizer (gun), polymerization into a 10 ~ 200 of the mist particles in direct contact with the hot air, heat exchange, drying is completed in a short period of time.　② pressure spray particulate device: M-type and S-type, with the liquid flow to produce a rotating guide groove, M-type guide groove axis perpendicular to the nozzle axis, not intersecting; S-type guide groove axis and the level of a certain angle. The purpose is: to try to increase the degree of turbulence of the solution when spraying.　(2) centrifugal spray drying method: ① principle: the use of horizontal direction for high-speed rotation of the disc to give the solution to centrifugal force, so that it is thrown out at high speed, the formation of films, filaments or droplets, due to friction of the air, obstruction, the role of tearing, with the tangential acceleration generated by the disc rotation and the centrifugal force generated by the radial acceleration, the results of a combined speed of the movement in the disc, whose trajectory is a helix, the liquid high with this Spiral from the disk thrown, it is dispersed into very small droplets with an average speed along the disk tangential direction of movement, while the droplets are subjected to gravity and fall, due to the spraying of particles of different sizes. Consequently, they fly different distances, so the particles fall at different distances to form a cylinder symmetrical to the center of the rotary axis.　② to obtain a more uniform droplet requirements: a. to reduce the vibration of the disk rotation b. into the disk liquid quantity in the unit time to maintain a constant c. disk surface is flat and smooth d. disk circumferential rate should not be too small, rmin = 60m / s, milk (100-160m / s) if & lt; 60m / s, the spray droplets are not uniform, the spray distance seems to be mainly composed of a group of liquid droplets and sinking to the disk near the A group of fine droplets composed of, and with the increase in speed and decrease.　③ centrifugal sprayer structure: requirements: long wetting perimeter, can make the solution to achieve high speed, spray uniformity, strong structure, light weight, simple, no dead ends, easy to dismantle, have a greater productivity. Classification according to the form of drying chamber According to the drying chamber in the hot air and the drying particles between the direction of movement classification: parallel flow type, countercurrent type, mixed flow type. The parallel flow type is often used in milk. Parallel flow type can be used to dry the higher temperature of the air inlet, without affecting the quality of the product.　a. Horizontal parallel flow type b. Vertical descending parallel flow type c. Vertical descending mixed flow type.　d. Vertical rise and flow type spray drying of food Some plants will lose their nutrients due to high temperature, for these plants, freeze drying is an effective method of concentration and preservation, however, some plants do need a certain temperature to remove toxicity, for these plants, spray drying technology is ideal. In the case of soybeans, for example, the concentration process requires a certain temperature to remove a substance called trypsin inhibitors (which prevent digestion and breakdown of proteins).　Spray drying is often the final step in the manufacturing process, which involves spraying, mixing, and drying a substance from a liquid to a powder. Among the many techniques used to store food, spray drying is uniquely superior. Because the temperatures used in this technique are not very high, it is possible to remove microbial contamination while still retaining the flavor, color and nutrients of the food.　Spray drying is commonly used to remove water from raw materials. In addition, it is used for a variety of other purposes, such as changing the size, shape or density of a substance, and it can assist in the addition of other ingredients during the production process, helping to produce products with the most stringent quality standards. How Spray Drying Works Before spray drying, soybeans must be cleaned and peeled, and non-protein components such as fat must be reduced in order to concentrate the most nutritious components of the soybeans before they can be spray dried. The actual process of spray drying is divided into several steps: first, the liquid product is fed into an atomizer, where a high-speed rotor atomizes the liquid, turning the product into a mixture of solid and liquid microparticles.　In the second step, the atomized particles are directed into a temperature- and airflow-controlled drying chamber, where hot air evaporates the liquid from the particles. In order for the final product to meet the standards, the particles must be exposed to the hot air for just the right amount of time to maintain a certain amount of moisture in the powder; at the same time, the state of the drying chamber must be well controlled, because the size of the chamber and the airflow conditions will affect the nutrition of the product.　In the third and final step of the process, the powder from the air stream is collected in a container by means of a separator, so that the final product is ready to be packaged or mixed with other ingredients. Features Fast drying speed. After centrifugal spraying, the surface area of the material is greatly increased, and in the high-temperature airflow, 95%-98% of the water can be evaporated instantly, and the drying time is only a few seconds.　The use of parallel flow spray drying form can make the droplets and hot air flow in the same direction, although the temperature of the hot air is higher, but because the hot air into the drying chamber immediately contact with the spray droplets, the indoor temperature drops sharply, and the wet bulb temperature of the material is basically unchanged, so it is also suitable for drying of heat-sensitive materials.