Principle of Flash Column
The principle of flash vaporization is to use high-pressure saturated liquid into a relatively low-pressure container, and due to the sudden drop in pressure, the saturated liquid becomes part of the saturated steam and saturated liquid under the pressure of the container. The use of this principle is relatively common.
At present, many piping systems in life use the flash column principle. The flash column is a very fast transition process. When the fluid flows through the regulating valve, the valve seat and the valve flap form a partially contracted flow area, resulting in local resistance. Making fluid pressure and velocity change to a certain extent. At the same time, when a fluid with a pressure of P1 flows through the orifice, the flow rate suddenly increases and the static pressure drops suddenly; when the pressure behind the orifice P2 reaches the saturated vapor pressure Pv of the fluid, part of the fluid vaporizes into a gas. The generated bubbles form a gas-liquid two-phase coexistence phenomenon, called the flashing stage, which shows that it is a systematic phenomenon.
At the same time, if the flash column principle is used in the pipeline system, it will damage the regulating valve to a certain extent. What can be done is to prevent the flash column from destroying the regulating valve so that the pipeline system can operate better.
The flash column adopts special air equipment to reduce the resistance of the equipment and provides an effective air dryer, which effectively extends the service life of the transmission components. The hot air is mixed, crushed, and dried from the bottom of the dryer through the inlet pipe at an appropriate speed. room. Drying tower drying time for wet materials is only 5 to 8 seconds, instant moisture evaporation, dry product quality and drying temperature, wind speed, air volume, crushing rate, adjustable flash drying tangential air inlet, adjustable discharge product particle size, and final moisture content.
The drying of flash columns is a common unit operation, and the production of APIs and preparations has been widely used. From heat transfer methods, convection, conduction, radiation, and so on.
The flash column is cut into a dry bottom by hot air, driven by a rotating agitator that forms a powerful wind field, a high-speed rotating impeller under a strong function, material influence, friction, and dispersed under the action of shear force. The material is quickly crushed and well in contact with hot air, heating, and drying, effectively preventing the material from sticking to the wall and deterioration of heat-sensitive materials and can be dried into uniform powder products, eliminating the broken classification and screening process.
The material of the flash column( such as Empty Flash Columns, Spherical SAX Flash Column) has strong shearing, floating, and rotating effects, the selection of various charging devices, continuous and stable feeding, and no bridge phenomenon occurs. In the process of introducing the concept of technology, the design is reasonable, the structure is compact, and it is an applicable wide range, large production capacity, good product quality, high efficiency, energy saving, equipment drying, crushing, screening one-time, eliminating environmental pollution, the performance of the flash column has reached the technical level.
When water is heated at atmospheric pressure, 100 ℃ is the highest allowable temperature for liquid water under this pressure. Reheating can not increase the temperature of the water, but can only convert water into steam. The heat absorbed by water in the process of heating up to the boiling point is called sensible heat, or sensible heat of saturated water.
The heat required to convert saturated water into steam at the same atmospheric pressure is called latent heat. However, if the water is heated at a certain pressure, the boiling point of the water will be higher than 100 ℃, so more sensible heat is required. The higher the pressure, the higher the boiling point of water, and the higher the heat content.
When the pressure decreases and some sensible heat is released, this excess heat will be absorbed in the form of latent heat, causing some water to be “flash” into steam, which is the working principle of the flash column.
Flash occurs in a pipeline system, which is easy to cause cavitation damage to the valve. Anti-cavitation high-pressure valve can be selected, which is characterized by multiple throttling and pressure sharing, and also can be used with anti-cavitation erosion materials.