Spray Dryer
Closed Cycle Spray Drying System
Time：2018.03.22
Spray drying is a drying method for rapidly drying liquid materials. After the liquid material is atomized in a drying chamber, the moisture in the contact with hot air instantaneously vaporizes to obtain a dry product. The method can directly make the solution and milk. The turbid liquid is dried into a powdery or granular product, which can save evaporation, concentration, smashing and other processes, and the obtained particles are evenly distributed.
Spray drying has the characteristics of rapid heat transfer, rapid evaporation of water, instant drying time, and good product quality, good dissolution performance, and can improve the dissolution rate of certain formulations. In addition, spray drying can also be used to prepare microcapsules.
With the progress of drying technology, at present, China has researched the closed loop circulation technology of spray drying. The core technology of this technology is to realize the dry production of the suspension liquid material in the form of centrifugal spray, but based on the centrifugal disk radial operating speed Slow (above the relationship between the operation speed of the atomizer disk and the volume of the atomizer disk, for which the operating speed of the centrifugal atomizer disk is relatively mature so far is 18000r/pm), and therefore, the liquid solid content of the centrifugal atomizer is limited to 10~30% range.
The closed cycle spray drying system is operated in a closed environment. The drying medium is an inert gas, generally N2. The materials suitable for organic solvents are used to dry poisonous materials or the drying of oxidation-prone materials during the drying process; Inert gas as a circulating gas has a protective effect on the dried material. The circulating gas undergoes a process of carrying moisture and dehumidification, and the medium can be reused.
In the process, according to the technical characteristics of different materials or process production requirements, the technical personnel design the corresponding process parameters in advance and input the control system. Such as heating and drying temperature, solvent recovery condensation temperature, pump operation speed or pressure, circulation fan air flow pressure, coolant flow and other process data programming input, the operator can be programmed to achieve automatic operation.
Due to the low solid content of atomization, not only the production capacity is affected, but also the energy consumption for dry production is increased correspondingly. The drying temperature is generally above 250° C. The quality of the finished powder is obtained by heating at a high temperature (due to the atomization The content is low, so the dried product is the powder structure). Therefore, high-temperature heating not only increases the energy consumption, but also has a great potential for accidents in the drying of liquid materials containing organic solvents. In addition, due to its centrifugal action, centrifugal spray can easily cause droplets to splash and adhere to the wall of the drying tower, resulting in extremely severe coking and sticking, and the technology does not have the function of solvent recovery, and there are still hidden dangers of secondary pollution. Whether the centrifugal spray closed circuit technology can meet the high solid content viscous and thick suspension liquid materials and have the organic solvent dry production needs further discussion.
Spray drying has the characteristics of rapid heat transfer, rapid evaporation of water, instant drying time, and good product quality, good dissolution performance, and can improve the dissolution rate of certain formulations. In addition, spray drying can also be used to prepare microcapsules.
With the progress of drying technology, at present, China has researched the closed loop circulation technology of spray drying. The core technology of this technology is to realize the dry production of the suspension liquid material in the form of centrifugal spray, but based on the centrifugal disk radial operating speed Slow (above the relationship between the operation speed of the atomizer disk and the volume of the atomizer disk, for which the operating speed of the centrifugal atomizer disk is relatively mature so far is 18000r/pm), and therefore, the liquid solid content of the centrifugal atomizer is limited to 10~30% range.
The closed cycle spray drying system is operated in a closed environment. The drying medium is an inert gas, generally N2. The materials suitable for organic solvents are used to dry poisonous materials or the drying of oxidation-prone materials during the drying process; Inert gas as a circulating gas has a protective effect on the dried material. The circulating gas undergoes a process of carrying moisture and dehumidification, and the medium can be reused.
In the process, according to the technical characteristics of different materials or process production requirements, the technical personnel design the corresponding process parameters in advance and input the control system. Such as heating and drying temperature, solvent recovery condensation temperature, pump operation speed or pressure, circulation fan air flow pressure, coolant flow and other process data programming input, the operator can be programmed to achieve automatic operation.
Due to the low solid content of atomization, not only the production capacity is affected, but also the energy consumption for dry production is increased correspondingly. The drying temperature is generally above 250° C. The quality of the finished powder is obtained by heating at a high temperature (due to the atomization The content is low, so the dried product is the powder structure). Therefore, high-temperature heating not only increases the energy consumption, but also has a great potential for accidents in the drying of liquid materials containing organic solvents. In addition, due to its centrifugal action, centrifugal spray can easily cause droplets to splash and adhere to the wall of the drying tower, resulting in extremely severe coking and sticking, and the technology does not have the function of solvent recovery, and there are still hidden dangers of secondary pollution. Whether the centrifugal spray closed circuit technology can meet the high solid content viscous and thick suspension liquid materials and have the organic solvent dry production needs further discussion.