Dry Ice
Solid carbon dioxide (C02) is sometimes used for cooling. Solid C02 is a white crystalline (for example, crystals) substances. It is formed when liquid carbon dioxide to depart into the snow chamber (heat-insulated Windows).
Heat for evaporation of fluid taken from the interior of the chamber. Very low temperatures (-108CF, -78C) is formed. As a result, the amount of carbon dioxide solidify. This solid clicking on various shapes and sizes and sold for cooling purposes. It has been given names such as dry ice, zero ice, and so on. He remains at a temperature -108F (-78aC), being in a solid state at atmospheric pressure.
Dry ice does not melt into a liquid. It goes directly from solid to the gaseous state. This is called sublimation." Dry ice has some desirable characteristics. He wet surfaces, with whom he comes into contact. The pair is given a preservative. Low temperature is maintained permit processing of frozen food products without the use of heavily insulated container.
Latent heat of sublimation 248 Btu/lb. Р¬77 kJ/kg).
Heat is absorbed vapor at the transition from 108F (78C) 32F (0C) is approximately 27 Btu/lb. (63 kJ/kg). This, added to the latent heat of sublimation, makes a total of heat-absorbing capacity of 275 Btu/lb. (640 kJ/kg).
Dry ice has a greater heat absorption capacity than not water ice. It is usually more expensive than water ice.
Equivalents
- 1 kJ/kg - 0.4299 Btu/lb.
- 1 Btu/lb. = 2,326 kJ/kg
Never put dry ice in the closed ware! At ordinary temperatures, dry ice will be sublime (evaporate). The resulting pressure can cause the container to explode. Avoid touching the dry ice. It will instantly freeze the skin..
|
Industrial