Flash refers to the saturated water and saturated water under the pressure of the container when the saturated water at high pressure enters the container at low pressure. In the process of chemical production, the flash tower can realize the rough gas-liquid separation of materials, and the flash tower can be roughly separated before entering the atmospheric furnace, so as to reduce the load of the atmospheric furnace.
When water is heated at atmospheric pressure, 100 °C is the highest temperature allowed for liquid water at that pressure. Reheating does not increase the temperature of the water, but only converts it into steam. The heat absorbed by water before it rises to the boiling point is called “sensible heat”, or the saturated water sensible heat. The heat required to convert saturated water into steam at the same atmospheric pressure is called “latent heat.”
However, if the water is heated under a certain pressure, the boiling point of water will be higher than 100 °C, so more sensible heat is required. The higher the pressure, the higher the boiling point of water and the higher the heat content. The pressure decreases and part of the sensible heat are released. This part of the excess heat will be absorbed in the form of latent heat, causing some water to be “flashed” into steam.
Working principle of the flash column: The method of flash column uses the volatility of each component in the liquid mixture, and uses the heat energy as a medium to partially vaporize it, thereby enriching the light component in the vapor phase and enriching the liquid phase in the liquid phase. The principle of using silica gel as stationary phase in flash column is an equilibrium between adsorption and desorption. So if the sample and silica gel adsorption are relatively strong, it is not easy to flow out. This will happen, the back point first out, and the front point after out. Then it’s better to adopt alumina as the stationary phase to prevent samples from leaking and allows the mobile phase to pass through.
In fact, in the distillation calculation of the flash column, each theoretical plate must perform such a flash calculation, but at this time the general name is called “equilibrium level” calculation, which is theoretically stricter, and its calculation content is exactly the same. Every rigorous or “flash” calculation or “equilibrium level” calculation must meet the following three major balances: mass balance, energy balance, and phase balance. Thus, a standard “flash” calculation module can handle changes in pressure (rise or fall) as well as the exchange of heat and work.
Therefore, a standard “flash” calculation module can handle both changes in pressure (increasing or decreasing) can also handle heat exchange and work exchange. The internal and external work exchange and heat exchange are mainly reflected in the energy balance, and the mass balance and phase balance mainly determine the vaporization fraction and vapor phase. In addition, there is a very important and difficult task in the “flash” calculation.
Flash column is to determine whether the state you specify is in the vapor-liquid two-phase, or only the vapor-phase or liquid-phase only. Moreover, the calculation of liquid-liquid equilibrium, in general, also requires “flashing” calculations. Of course, some software orders come out because the calculation is more difficult. The above description of “flashing” is only one word, not very rigorous, but relatively more accurate. In short, whether you use PROII, ASPEN or H “YSIS, Flash” calculation is really its most basic core.
The exchange of internal and external work and heat exchange are mainly reflected in the energy balance, while the mass balance and phase balance mainly determine the vaporization fraction and the composition of the vapor and liquid phases. In addition, the “flash” calculation has a very important and difficult task, which is to judge whether the state you specify is in the vapor and liquid phases, or just the vapor phase or liquid phase only. In addition, the calculation of liquid-liquid equilibrium generally requires the “flash” calculation, of course, some software is taken out alone because the calculation is more difficult.
Operating principle of Flash column
Flash column is when the saturated water at high pressure enters the container at low pressure and becomes saturated water vapor and saturated water under the pressure of the container due to the sudden decrease of the pressure. By taking advantage of the differences in the volatilization of the components in a liquid mixture, the method of partially vaporizing the components in the vapor phase with the medium of heat energy to enrich the light components in the liquid phase and separate them by combining the components.
Causes of the flash column
When using Spherical SCX Flash Column, water is heated at atmospheric pressure, 100℃ is the maximum temperature allowed for liquid water at that pressure. Reheating does not raise the temperature of the water but converts it into steam. The heat absorbed by water in the process of heating 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 under 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 drops, some sensible heat is released, and this excess heat is absorbed in the form of latent heat, causing part of the water to “flash” into steam.
The actual situation of the Flash column
Flash column appears in the pipeline system, easy to cause cavitation damage to the valve, you can choose an anti-cavitation high-pressure valve, its characteristics are multiple throttle allocation of pressure difference, also can choose cavitation erosion material. Flash can also be used as energy for recovery of boiler drainage and geothermal power generation in thermal power plants.