Regarding the flash tank

Principle of flash evaporation Flash evaporation is different from distillation, as no heat is added during the flash evaporation process. The principle is simple: the boiling point of a substance increases as pressure rises. So, does that mean that the lower the pressure, the lower the boiling point? Well, in that way, the high-pressure and high-temperature fluid can be depressurized, thereby reducing its boiling point, and then it can enter the flash tank. At this point, the fluid temperature is higher than the boiling point at that pressure. The fluid rapidly boils and vaporizes in the flash tank, resulting in two-phase separation. The device that brings the fluid to a gaseous state is not a flash tank, but a pressure relief valve. The function of a flash tank is to provide a space for rapid vaporization of the fluid and gas-liquid separation. It can be seen that flashing also comes at a cost, which is the loss of pressure energy. In a nutshell, flashing is the process by which fluid boils under reduced pressure, resulting in both vapor and liquid phases. Establish the vapor-liquid equilibrium at a new pressure level. It is mostly used for pure substances. 　　\"FLASHING\" is indeed a metaphorical term derived from the phenomenon of vapor-liquid separation caused by pressure reduction, but its strict definition applies to much more than just that. A more precise definition relates it to a thermodynamic equilibrium state.

A more strict definition is the calculation of the change from one thermodynamic equilibrium state to another. Therefore, if the change between two thermodynamic states involves only a decrease in pressure, with no exchange of work or heat. According to Henry’s law P=EX, the solubility of gas-phase solutes in the liquid solvent varies at different temperatures and partial pressures. When the solvent pressure decreases, the solute in the solvent is rapidly desorbed and released automatically, resulting in flashing. The energy for flashing is provided by the solvent itself, so the temperature of the solvent decreases during the flashing process. From a higher constant pressure to a lower constant pressure, when desorption equilibrium is reached, the amount of solute desorbed remains constant, and the amount of solute remaining in the solvent also remains constant. Therefore, there is only one control target for flashing, and that is the flashing pressure. Henry’s law is one of the fundamental laws in physical chemistry; it was discovered by the British scientist W. Henry in 1803 while studying the laws governing the solubility of gases in liquids. It can be expressed as follows: “At a constant temperature, the concentration of a certain gas in a solution is proportional to the equilibrium pressure of that gas above the liquid surface.” "Experiments show that this law holds true only when the solubility of the gas in the liquid is not very high; in such cases, the gas acts as a volatile solute in a dilute solution, and the gas pressure corresponds to the vapor pressure of the solute. Therefore, Henry’s law can also be expressed as follows: at a constant temperature, the vapor pressure of a solute in a dilute solution is proportional to the concentration of the solution: pB = kxB, where pB represents the vapor pressure of the solute in the dilute solution ； xB is the mole fraction of the solute ； k is the Henry constant, whose value depends on temperature, pressure, and the nature of the solute and solvent. Since various concentrations in a dilute solution are proportional to each other,xB in the above equation can also be mB (mass molar concentration) or cB (mole concentration), etc.; in such cases, the value of k will change accordingly. 　　Henry’s law applies only when the molecular states of the solute in the gas phase and the liquid phase are identical. If the solute molecules undergo dissociation, association, etc. in the solution, then xB (or mB, cB, etc.) in the above equation should refer to the concentration of the portion that is in the same molecular state as that in the gas phase ； When the total pressure is not high, if multiple gases are dissolved in the same liquid, Henry’s law can be applied separately to each of these gases ； Generally speaking, the weaker the solution, the more accurate Henry’s law becomes; as xB→0, the solute can strictly obey the law. 　　Principle: It mainly relies on the decrease in vapor pressure under pressure, which causes more solvent (usually water) to flash into a gaseous state, thereby achieving concentration. 　　Structure: Very simple. The diameter should be a bit larger; it’s a bit like a cyclone separator. Of course, a certain height must be maintained, otherwise the liquid will also leak out. 　　Vaporization occurs when saturated water under high pressure is introduced into a container at lower pressure; the sudden drop in pressure causes this saturated water to turn into both saturated steam and saturated water at the pressure of the container. 　　Reason for formation: When water is heated under atmospheric pressure, 100°C is the highest temperature that liquid water can reach at that pressure. Reheating cannot increase the temperature of water; it can only turn the water into steam. The heat absorbed by water as it is heated to its boiling point is called \"sensible heat,\" or specific heat of saturated water. The heat required to convert saturated water into steam at the same atmospheric pressure is called \"latent heat\". However, if water is heated under certain pressure, its boiling point will be higher than 100°C, which requires more sensible heat. The higher the pressure, the higher the boiling point of water, and the greater its heat content as well. As the pressure decreases, some of the sensible heat is released; this excess heat is then absorbed in the form of latent heat, causing some of the water to be \"vaporized\" into steam.

By reducing pressure, the light hydrocarbons in the amine-rich liquid are vaporized and separated from it.

The pressure drops suddenly from high to low, and the hydrocarbons dissolved in it change from a liquid phase to a gas phase; is that correct?

Thank you, in other words, the high-temperature and high-pressure liquid passes through a pressure reducing valve; after the pressure is reduced, it goes into the flash tank. The light components flashed off. That is, it’s the light hydrocarbons; what remains is the amine-rich liquid. This is the principle and purpose of flashing.

If there is light dirty oil on the amine liquid level in the flash tank, does that indicate poor flashing efficiency or a possible leak in the intermediate partition? :$:)

The principle is to reduce pressure and lower the boiling point, thereby enabling the liquid to vaporize rapidly