Superheated evaporator and subcooled condenser
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What is the status of the superheated evaporator and the subcooled condenser? Regarding the evaporator, how is superheating achieved? As for the condenser, it seems to be easy to understand. Any specific examples to look at?
It refers to the temperature at the saturation pressure corresponding to each channel within the device; a temperature higher than this saturation temperature is called \"superheated,\" while a temperature lower than it is called \"subcooled.\" For example, at atmospheric pressure, the saturation temperature of water vapor is set at 100°C; when the pressure remains constant, the degree above this temperature is called \"superheat.\" If, at atmospheric pressure, the boiling point (vaporization temperature) of water is set at 100°C, then the degree below this temperature is referred to as \"subcooling.\" If the temperature of water in nature is 20°C, then its supercooling degree is approximately 70°C. It is recommended to download a book on Principles of Chemical Engineering, as it is essential as a foundational text. (For reference)
Thank you. I was wondering, have you ever seen a superheated evaporator?
Try understanding the cooler in reverse: lol
This post was last edited by wiseboy on 2018-6-26 at 16:56. Summary answer: In any situation where gas and liquid coexist, there is no stable superheated steam state. Because the steam temperature is the temperature of vapor-liquid equilibrium, not the superheated temperature. To overheat it, it is necessary to continue heating it while the steam leaves the liquid. In other words, if the evaporator is to produce superheated steam, it must have two sections: an evaporation section (where gas and liquid coexist) + a superheating section (with no liquid). Such an evaporator can be designed, but it is better to use two heat exchangers: one for evaporation (gas-liquid phase change) and another for superheating (heating of single-phase steam). ）
Thank you. I saw the term \"overheating evaporator\" mentioned in some text, so it must exist; I just haven’t encountered it yet. I’m curious if it’s available in the chemical engineering system. Perhaps it does exist: a direct-flow boiler without a steam-water separation drum, where vaporization occurs directly, followed by superheating, as long as the heat exchange surface is present.
This post was last edited by xjhaooo on 2018-6-27 09:25. The DC boiler you mentioned does indeed work in that way – there is no more steam-water separator between the evaporation surface and the superheating surface. But this all takes place inside the tubes; evaporation occurs outside the tubes, and I have never seen a case where superheating takes place directly without a separator. Furthermore, in supercritical units with DC boilers, once the water inside the tubes reaches its saturation temperature, all of the liquid water undergoes direct phase transformation into dry steam, with no two-phase mixture remaining. But this only exists above the critical pressure, which is a little over 22 MPa.
Our material is vaporized, transitioning from the liquid phase to the gas phase, and the gas phase is then further superheated.