how do they get dry Ice to freeze?

Question

I understand that dry ice is just frozen co2, but how do they get the dry ice to those extremely low temperatures? I tried googling it but no satisfying answers came up. Can someone explain?

In: 5

Answer 1

If you take carbon dioxide and pressurize it, it will heat up.

If you take carbon dioxide at a high pressure and release the pressure it cools off.

So what you do is pressurize carbon dioxide then let it cool off using heat exchangers to dump the heat produced. Then you release the pressure and it cools off enough to turn solid