When saltwater evaporates, will the water that remains contain salt?
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When saltwater evaporates, will the water that remains contain salt? Salt dissolving in water is a physical process; there is a physical bond between salt ions and water molecules. Evaporation is the process by which water molecules change from a liquid state to a gas state, and it is also a physical process. Since both are physical processes, it follows that evaporation must carry away some salt along with the water vapor, right? But what’s the truth? (Thinking of this makes me feel a bit uncomfortable; is it because the facts don’t conform to normal human reasoning?) Do I have OCD myself? ）
In fact, salt does evaporate
Steam contains salt because the gas is humid, with mist being carried along
The condensed liquid from evaporation does contain salts, but not in the way you might think; it’s caused by steam carrying along the mother liquor； The design can achieve virtually no salt content
Since there is indeed the presence of entrained mist, and this may vary with operational conditions, two points deserve attention: 1) The material selection for equipment and pipes that come into contact with secondary steam condensate still needs to take into account resistance to corrosion by chloride ions as well as other anions and cations； 2) The appropriate ways of utilizing and disposing of secondary steam condensate clearly cannot treat it as ordinary steam condensate.
Do you know something called gas-liquid entrainment? Theoretically, water that is completely free of salts hardly exists; even Tesco’s distilled water has a certain conductivity. Theory remains theory, and in reality, everything is part of complex systems when examined closely
This isn’t called “facts not conforming to normal human reasoning”; at best, it’s just that you’re approaching a matter with a crude, ordinary way of thinking
Metal ions are mainly entrained in the mist. Non-metals or metals with low boiling points will evaporate; therefore, wastewater treatment has feed requirements for certain types of media
If you’re asking from a theoretical perspective, then it’s not included; engineering design also suggests that it’s not necessary. But in reality, since steam carries the solution with it, it is essential