Dry ice is usually made by placing liquid carbon dioxide in a high-pressure environment, and no other chemicals or impurities are added in the manufacturing process. Therefore, dry ice is relatively pure and will not cause obvious pollution and harm to the environment and human body. However, it should be noted that the temperature of dry ice is very low, which can reach -78.5℃, so it is necessary to pay attention to safety during use.
Sublimation under normal pressure can make the surrounding temperature drop rapidly, so dry ice will liquefy and even further condense the water vapor in the air when sublimating in the air, and the formed water vapor droplets or small ice crystals will adhere to the dust in the air to form white smoke that we can see. The crystal structure of dry ice is simple cubic and belongs to molecular crystal.
Application of dry ice:
1, petrochemical industry: dry ice cleaning technology can be used to clean the rust dust of main fans, air compressors, hoods, steam turbines, blowers and other equipment in the petrochemical process (it is not necessary to remove the blades and omit the step of readjusting the dynamic balance of the blades); Removal of coking and carbon deposition in various heating furnaces and reactors; Clean the PVC resin on the heat exchanger; Remove oil stains, rust and dust from compressors, storage tanks, boilers, reaction vessels, condensers, complex machines and other equipment.
2. Power system: it can directly clean indoor and outdoor transformers, insulators, power distribution cabinets, wires and cables under live load (below 37kV); Generator, motor, rotor, stator and other parts are cleaned without damage.
3. Food production: Dry ice cleaning can successfully remove baking residues, colloidal substances and oil stains in the oven and the mixture of fresh products before baking. Effectively clean ovens, mixing and stirring equipment, conveyor belts, molded products, packaging equipment, furnace racks, furnace plates, containers, rollers, inner walls of freezers, biscuit bars and other equipment.
4. Automobile and ship industry: cleaning the car doorskins, roofs, carriages and car bottoms has no water stains, which will not cause water pollution; Car carburetor cleaning and car surface paint removal; Removing carbon deposits from the engines of vehicles and boats; Clean the hull, seawater suction valve, seawater condenser and heat exchanger, engine room, machinery and electrical equipment, etc.
Reference to the above content: Baidu Encyclopedia-Dry Ice