this post was submitted on 07 Jul 2023
307 points (98.7% liked)

Asklemmy

43945 readers
28 users here now

A loosely moderated place to ask open-ended questions

Search asklemmy ๐Ÿ”

If your post meets the following criteria, it's welcome here!

  1. Open-ended question
  2. Not offensive: at this point, we do not have the bandwidth to moderate overtly political discussions. Assume best intent and be excellent to each other.
  3. Not regarding using or support for Lemmy: context, see the list of support communities and tools for finding communities below
  4. Not ad nauseam inducing: please make sure it is a question that would be new to most members
  5. An actual topic of discussion

Looking for support?

Looking for a community?

~Icon~ ~by~ ~@Double_[email protected]~

founded 5 years ago
MODERATORS
you are viewing a single comment's thread
view the rest of the comments
[โ€“] [email protected] 8 points 1 year ago (1 children)

I would guess that's hot vapor, not steam. Actual steam is invisible and will burn you

[โ€“] [email protected] 2 points 1 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.