Dry ice is usually made by putting liquid carbon dioxide in a high-pressure environment, and no other chemicals or impurities are added during 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 attention should be paid to safety when using it.
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 ice crystals will attach to the dust in the air, forming white smoke that we can see. The crystal structure of dry ice is a simple cube 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, which saves the step of readjusting the dynamic balance of the blades); Remove 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 and live wires and cables (below 37kV); Generator, motor, rotor, stator and other parts are clean and free from damage.
3. Food production: Dry ice cleaning can successfully remove baking residues, colloidal substances, oil stains and fresh product mixtures before baking in the oven. Effectively clean ovens, mixing and stirring equipment, conveyor belts, molded products, packaging equipment, stoves, stoves, containers, rollers, inner walls of freezers, biscuit sticks and other equipment.
4. Automobile and shipbuilding industry: cleaning the doorskin, roof, carriage and bottom of the car without water stains will not cause water pollution; Cleaning of automobile carburetor and removal of automobile surface paint; Removing carbon deposits from engines of vehicles and ships; Clean the hull, seawater suction valve, seawater condenser and heat exchanger, engine room, mechanical and electrical equipment, etc.
Reference to the above content: Baidu Encyclopedia-Dry Ice