The classification of Laboratory scale spray dryers

Glass reactors operation according to different characteristics, operating pressure, heating the wet material movement pattern or structure classification. Following the procedure, the dryer is divided into (batch operation) types of batch and continuous
Press the operating pressure, the dryer is divided into two types of pressure dryer and vacuum dryer, operating in a vacuum space can be reduced partial wet steam partial pressure to accelerate the drying process, and can reduce boiling point and material moisture drying temperature, steam is not easy leakage, so a vacuum Laboratory scale spray dryers is suitable for drying heat-sensitive, easily oxidized, explosive and toxic materials need to be recycled and moisture vapor occasions

By heating, convection dryer into, conduction, radiation type, dielectric type and other types. Also known as convection dryer direct dryers, the drying medium is in direct contact with the wet material using heat to convection heat transfer, and the resulting steam away; also known as indirect conduction drier dryer, which uses conduction way to transfer heat from the heat source to the wet material through a metal partition, the resulting steam is available vacuum suction moisture, which leads to a small amount of purge gas or cryogenic condenser surface condensation methods such as separately provided removed. Do not use this type of dryer the drying medium, high thermal efficiency, the product is not contaminated, but the drying capacity limit heat transfer area by the metal wall, the structure is also more complex, often operating under vacuum; radiation dryer is the use of various radiation It emits a certain wavelength range of electromagnetic waves, the surface after being wet material is selectively absorbed into heat for drying; dielectric dryer is the use of a high-frequency electric field, so that the internal thermal effect wet material was dried.
By movement of the wet material, the dryer can be divided into a fixed bed, agitated, spray and modular; according to the structure, the dryer can be divided into Van dryers, conveyor dryers, drum dryers, Li dryers, mechanical agitation dryers, rotary dryers, fluid bed dryers, gas stream type dryers, vibration dryers, spray dryers and other dryer and combined.
For drying wet materials equipment. Subject to various production processes dried material is varied, the drying requirements also vary, therefore drier variety, according to the heating mode, the following four categories: 1 convection dryer
The most widely used class dryer, including a fluidized dryer, air dryer, Van dryer, spray dryer, a tunnel dryer and the like. The main features of these dryers are: ① direct contact with the hot gas and solid heat in the convective heat transfer from the hot gas circulating manner to wet the solid, water vapor generated by the airflow away; ② hot air temperature can be increased to ordinary metal materials The maximum temperature (about 730 ℃) can be tolerated at a high temperature radiant heat transfer will be the main mode of heat transfer, and can reach very high heat utilization; ③ airflow humidity final moisture content of the drying rate and product have influence; ④ When using a low temperature airflow, usually need to first make the dehumidification process gas stream; ⑤ vaporization energy per unit mass than the conduction dryer moisture is high, the final product moisture content is low even worse; ⑥ need a lot of hot air in order to guarantee the heat of vaporization of water required, if the particle size of the material to be dried is small, the dust and the huge cost means higher; ⑦ should be operating at near ambient conditions. 2 conduction dryer
Including screw conveyor dryers, drum dryers, vacuum rake dryer, freeze dryer, the main characteristics of this type of dryers are: ① heat through the wall (usually metallic wall), to pass the wet heat conduction material ; ② the surface temperature of the material from below freezing (freeze-drying time) to 330 ℃; ③ easy to operate under a reduced pressure and an inert atmosphere, volatile solvent recoverable. Commonly used in easily oxidized, easy to break down dry materials, also applies to the handling of powdered materials. 3 radiation dryer
Heat transfer by radiation, heating the wet material to dry. Electric heating by infrared radiation dryer light bulbs dry material, the material temperature and dry. Gas heating combustion gas dryer is a metal or ceramic radiant panel is heated to 400 ~ 500 ℃, thus producing infrared, for heating the material to be dried. Radiation dryer production strength, compact device, the use of flexible, but consume more energy. Suitable for drying large surface and thin materials, such as plastic, cloth, wood, paint products