Dry ice is a solid form of carbon dioxide, a colorless and odorless gas that naturally exists in the air. Although the content of carbon dioxide in air is relatively small (about 0.03% by volume), it is one of the most important gases we know. Dry ice is volatile and sublimates into nontoxic and odorless gas carbon dioxide, which is 1000 times larger than the solid volume, so dry ice cannot be stored in a container with good sealing performance and small volume, and it is easy to explode. It is safe to put dry ice in a well-ventilated place and let the gas generated by dry ice volatilization be released.

Ice is solid carbon dioxide. At normal temperature and pressure of 6079.8 kPa, carbon dioxide condenses into colorless liquid, and then rapidly evaporates at low pressure, and then condenses into pieces of compacted ice-like solid matter, the temperature of which is-78.5℃, which is dry ice. The cold storage capacity of dry ice is more than 1.5 times that of water ice. After absorbing heat, it sublimates into carbon dioxide gas, which has no residue, toxicity and odor, and has sterilization effect. Directly sublimate after heating, without liquefaction. Dry ice is the solid state of carbon dioxide. Because the temperature of dry ice is very low, the temperature is MINUS 78.5℃, so it is often used to keep objects in a frozen or low temperature state.

At room temperature, when carbon dioxide gas is pressurized to about 10 1325Pa, a part of steam will freeze into snowflake-like solid carbon dioxide when it is cooled to about -56℃. The gasification heat of solid carbon dioxide is very high, which is 364.5 J/g at -60℃. During atmospheric gasification, the ambient temperature can be reduced to about -78℃ and no liquid will be produced, so it is called "dry ice". Dry ice can also be used as artificial rainfall, which can quickly absorb a lot of heat in the air, make the surrounding temperature drop rapidly, and liquefy water vapor into small water droplets, thus achieving the purpose of rainfall. In addition, AgI and other substances have similar properties.

applied range

Industrial mould industry

Tire mold, rubber mold, polyurethane mold, polyethylene mold, PET mold, foaming mold, injection mold, alloy die-casting mold, hot core box for casting and cold core box can remove residual resin, invalid release layer, carbonizing film agent and oil stain, and can open air holes. After cleaning, the mold is as bright as new.

Online cleaning, no need to cool and disassemble the mold, avoiding corrosion and damage to the mold by chemical cleaning and mechanical cleaning.

This method causes mechanical damage and scratches to the mold, as well as the decline of mold accuracy caused by repeated loading and unloading. Crucially, the two most time-consuming steps of removing the mold and waiting for the mold to cool can be omitted, and the downtime can be reduced by about 80%-95%.

Benefits of dry ice cleaning: dry ice cleaning can reduce downtime; Reduce equipment damage; Very effective cleaning of high-temperature equipment; Reduce or reduce the use of solvents; Improving the safety of staff; Improve maintenance efficiency; Reduce production downtime, reduce costs and improve production efficiency.

petrochemical industry

Clean the main fan, air compressor, fume hood, steam turbine, blower and other equipment to remove coking and carbon deposition in various heating furnaces and reactors. Clean the PVC resin on the heat exchanger; Remove oil stains, rust, hydrocarbons and dirt on the surfaces of various pressure vessels such as compressors, storage tanks and boilers; Cleaning the reaction kettle and condenser; Complex biological purification; Furnace tube cleaning, etc.

Food and pharmaceutical industries

It can successfully remove baking residues, colloidal substances and oil stains in the oven, as well as the mixture of fresh products before baking. Effectively clean ovens, mixing and stirring equipment, conveyor belts, molded products, packaging equipment, stoves, stoves, containers, rollers, refrigerator inner walls, biscuit stoves, etc.

Benefits of dry ice cleaning: put an end to the use of harmful chemicals, and avoid production equipment contacting with harmful chemicals and generating secondary garbage; Prepare or remove bacteria such as Salmonella and Listeria, and disinfect and clean more thoroughly; Eliminate the damage of water jet cleaning to electronic equipment; Minimum equipment decomposition; Reduce downtime.

press

It is difficult to remove ink accumulated on gears and guide rails.

Will lead to poor print quality. Dry ice cleaning can remove all kinds of oil-based and water-based inks and varnishes, clean up oil stains, accumulated inks and dyes on gears, guide rails and nozzles, and avoid the discharge of harmful wastes and solutions and personal injuries caused by harmful solvents.

power industry

Can clean electric boilers, condensers and various heat exchangers; Can directly clean indoor and outdoor transformers, insulators, power distribution cabinets, live wires and cables (below 37KV); Generator, motor, rotor, stator and other parts are clean and free from damage; Clean the rust, hydrocarbon and adhesive powder on turbines, impellers, blades and other parts, without disassembling the blades and readjusting the dynamic balance of the blades.

Benefits of dry ice cleaning: effectively decompose pollutants to be cleaned; Because these pollutants are removed, the power loss is reduced; The maintenance cost of external equipment and its basic equipment is reduced; Improve the reliability of power system; Keep the insulator intact and non-abrasive clean; More suitable for preventive maintenance.

automotive industry

Cleaning the doorskin, roof, carriage, car bottom and other oil stains will not cause water pollution; Cleaning of automobile carburetor and removal of automobile surface paint; Remove carbon deposits from the engine. If the carbon deposit is treated, it will take a long time to treat it with chemical agents, at least more than 48 hours, which is harmful to human body. Dry ice cleaning can completely solve the problem of carbon deposition within 10 minute, saving time and reducing cost, and the scale removal rate reaches 100%.

electronic industry

Clean the grease and dirt inside robots and automation equipment; Clean the integrated circuit board, post-welding flux, pollution coating, resin, solvent coating, protective layer and photosensitive corrosion inhibitor on the printed circuit board.

8. Application scope of dry ice in aerospace

Pre-coating treatment and final assembly of missiles and aircraft; Paint removal of composite molds and special aircraft: engine carbon cleaning; Maintenance and cleaning (especially the landing gear-wheel well area); Depainting of aircraft shells: jet engine conversion system. Can work directly in the body, saving time.

shipping industry

Hull; Seawater suction valve; Seawater condenser and heat exchanger; The machine room, machinery and electrical equipment are cleaner than ordinary high-pressure water jet cleaning.

nuclear industry

If the nuclear industry equipment is cleaned by traditional cleaning methods such as water, sand blasting or chemical detergent, the media such as water, sand blasting or chemical detergent will also be polluted by radioactive elements, so it takes time and money to treat these secondary polluted media. In the process of dry ice cleaning, dry ice particles are directly sprayed on the object to be cleaned, which instantly sublimates, and there is no problem of secondary pollution. All that needs to be treated is the cleaned waste with nuclear pollution and scale.

Cosmetic industry

Some dermatologists use dry ice to treat acne, which is called cryotherapy. Because it will slightly freeze the skin.

There is a frozen substance for treating acne, which is mixed with ground dry ice, and sometimes some sulfur is added. Liquid nitrogen and solid dry ice can also be used as cryotherapy materials. Cryotherapy can reduce inflammation. Some time ago, the news reported that Liu Xiang used this cryotherapy to treat acne on his face. This method can reduce the generation of acne scars, but it is not used to remove scars.

food service industry

1. Add dry ice to wine, cocktail or drink, it will be cool and delicious when drinking, and the cup will be filled with smoke, which is very pleasant.

2. Add dry ice when making ice cream, and the ice cream will not melt easily. Dry ice is especially suitable for cold storage of takeaway ice cream.

3. Adding dry ice to seafood dishes in star-rated hotels and restaurants can create a white smoke landscape and improve the level of banquets, such as making lobster sashimi.

4, lobster, crab, shark fin and other seafood frozen and refrigerated. Dry ice will not change water, and it is cleaner than water-cooled storage. Widely used in Europe, America, Japan and other countries.

Refrigerated transportation field

1, cryogenic refrigeration for medical use and cryogenic transportation of special drugs such as plasma and vaccines.

2. Long-distance and short-distance transportation of electronic cryogenic materials and precision components.

3. Fresh-keeping transportation of high-grade foods such as high-grade beef and mutton.

Entertainment field

Widely used in stage, theater, film and television, wedding, celebration, party and so on. There are countless special effects classic plays made of dry ice in China and even in the world.

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15. Application scope of dry ice in fire protection industry

Dry ice is used to put out fires, such as some low-temperature fire extinguishers, but the application of dry ice in this respect is less, that is, the market level is low.