The Basics on Dry Ice
Dry ice is a condensed compound in the atmosphere known to man as carbon dioxide. Dry ice is used for many purposes. For example dry ice is used most to freeze, and keep things frozen because of its very cold temperature: -109.3F or -78.5C (-51.5K). Dry ice is widely used because it is simple to convert to its frozen form and easy to handle using insulated gloves.
How Dry Ice Is Made
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 CO2 gas will liquefy at a pressure approximately 870 psi. at room temperature. Next, the pressure is reduced over the liquid carbon dioxide by sending it through an expansion valve. Part of the liquid evaporates, causing the remainder to cool. As the temperature drops to -109.3F,
the temperature of the frozen CO2, some of it will freeze into snowflakes. This dry ice snow is then compressed together under a large press form blocks. Dry ice is much heavier than traditional ice, weighing about double.
Critical Density28.9855 LB/FT3
Critical Pressure1066.3 PSIA
Density Gas0.1234 LB/FT3@32F
Density Liquid63.69 LB/FT3@0F
Latent Heat of Vaporization241 BTU/LB 0F
Sublimation Temperature-109.3F 04 -78.5C
Solubility in H2O79FT3 CO2 BAS/FT3 (when H2O is at 32F)
Triple Point-69F 75.1 PSIA
Viscosity Gas0.015 Centipoises @32F
Viscosity Liquid0.14 Centipoises @0F
SublimationA point of Dry Ice sill sublimate into 8.3 cubit feet of carbon dioxide gas.
DOT Shipping Class:ORM-A UN-1845 Pkg. Group III Class
Nonflammable Gas UN2187
Dry ice can add the right touch to the typical school volcano. The "smoke" will come out the top and flow down the sides for several minutes.