0 Members and 1 Guest are viewing this topic.
The first step in making dry ice is to compress carbon dioxide gas until it liquefies, at the same time removing the excess heat. The C02 gas will liquefy at a pressure of approximately 870 pounds per square inch at room temperature. Next, the pressure is reduced over the liquid carbon dioxide by sending it through an expansion valve into an empty chamber. The liquid will flash, with some turning into gas causing the remainder to cool. As the temperature drops to -109.3°F, the temperature of frozen CO2, some of it will freeze into snow. This dry ice snow is then compressed together under a large press to form blocks or extruded into various sized pellets.
Recently I came across a picture of dry ice being poured out of a test tube. Does anyone know how this "dry ice" is created? and why the water in its gas state looks completely different (like a really heavy white mist)?