• @nickajeglin@lemmy.one
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      21 year ago

      There are a few kinds of steam!

      Wet (unsaturated) steam: this is probably what’s coming out of the instant pot. It’s gasified water mixed with tiny particles of liquid water. Industrial processes do not want wet steam in their systems. They have machinery to separate the liquid out. If that liquid water settles out inside a pipe and blocks it, it’ll go shooting down the pipe like a bullet and cause damage to whatever is at the end of the line. If the droplets get into turbomachinery, they’ll tear up the turbines. Adding additional heat will not increase the temperature, but will get consumed by the phase change to evaporate the remaining water and change the wet steam into…

      Dry (saturated) steam: this is precisely the point when all the water has been evaporated. If you remove heat, it will start to condense without changing temperature. If you add additional heat, it will increase the temperature of the steam, because there is no water left to evaporate. This is useful because changing phase between liquid and gas consumes/yields a ton of energy, and that happens at a constant temperature. So if you need to transfer heat from one place to another, then saturated steam is what you want. Adding heat to saturated steam gets you…

      Superheated steam: at this point you can conceptualize water as a gas. Intuitively, it works just like air or nitrogen or whatever. Pressure/temp relationships act like you’d expect from your everyday experience, because you’re far enough above the gas-liquid phase change temperature that you don’t have to worry about condensation getting into your equipment. If you want to use steam as a working fluid in turbomachinery or something, then you want superheated steam.

      All three can hurt you badly, but inadvertent contact with superheated steam will fuck you up or cause irreversible death.