Reducing the pressure of liquid carbon dioxide, part of liquid carbon dioxide evaporates and absorbs a lot of heat, so that the other part of carbon dioxide cools into a snow-like solid. Compacting snow-like solid carbon dioxide to obtain dry ice. (Or liquid carbon dioxide can be cooled to -2 1. 1℃ and the pressure is 0.4 15MPa, or solid carbon dioxide can be formed. )
The simple method is to put a canvas bag on the mouth of the container containing liquid carbon dioxide, and then open the container to release carbon dioxide, so that some dry ice can be collected in the pocket. Mass production needs a special dry ice maker.
Dry ice should be stored in high-pressure steel cylinders. If there is no high-pressure steel cylinder, it can be stored in the freezer of the refrigerator for 5 ~ 10 days.
Question 2: How to make dry ice by yourself? At normal temperature and pressure, carbon dioxide is gas, while dry ice is solid carbon dioxide. Theoretically, as long as it is below its sublimation temperature, carbon dioxide can be solidified into a solid state to obtain dry ice; But in fact, how does the general equipment reach this temperature?
At present, dry ice is usually pressurized at room temperature to obtain liquid carbon dioxide, and then evaporated at low temperature. In the evaporation process, part of the liquid is cooled and solidified to obtain dry ice.
Dry ice can be made by a dry ice maker. Its raw material is not direct gaseous carbon dioxide, but liquid carbon dioxide, which still solidifies into solid particles after evaporation and cooling. About 40% of liquid carbon dioxide is converted into solid dry ice.
As a daily experiment, you can use an ordinary carbon dioxide fire extinguisher: turn on the safety of the fire extinguisher and quickly release the gas in the cylinder. You can see the white "snowflake" falling near the nozzle, that is, dry ice, because the gas in the steel cylinder absorbs heat and expands rapidly near the nozzle, so that the nearby temperature drops rapidly to form a low temperature, and some carbon dioxide solidifies into a solid state in this environment.
This test should pay attention to safety and operate in strict accordance with the operating procedures of carbon dioxide flower killer. Don't touch the metal nozzle directly with unprotected hands, just grab the wooden handle and don't spray people.
Question 3: How to make the materials needed for dry ice? The method relates to a preparation process of dry ice, which comprises the following steps: firstly, putting carbon dioxide into a container, then putting it into a cooling chamber for preliminary pre-cooling treatment, wherein the pre-cooling temperature is-65438 +- 00 +- 20 DEG C, standing for 65438+-00+-20 minutes, and then entering a forced refrigeration chamber for forced refrigeration, wherein the refrigeration temperature is-80 DEG C-65438+. Advantages: simple process and easy manufacture. The dry ice made by this method has high density, good compactness, crystal color and long volatilization time, and can be used in the production of various beverages and the cleaning project of dry ice. Patent * * * Project 1. A process for preparing crystalline dry ice is characterized in that the process for preparing crystalline dry ice is as follows: (1), firstly, liquid carbon dioxide is injected into a special container, and forced fins are installed outside the container, so that the heat dissipation performance is good; (2) putting a container filled with carbon dioxide into a primary cooling chamber for pre-cooling, wherein the pre-cooling temperature is-10-20 DEG C, and standing for10-20 minutes; (3) cooling the cooled carbon dioxide at-80℃-120℃ for 20-30 minutes; (4) after cooling, making crystalline dry ice in a container; (5) entering a demoulding chamber, and performing micro-thermal demoulding; (6) After demoulding, high-density crystalline dry ice is obtained.
Question 4: How to simply make dry ice at home? Making dry ice requires special compressors, freezers, flash tanks and other equipment, which are not available at home. And there is no special protective clothing, which is easy to cause cold burns.
Question 5: How to make dry ice at home can be done, but it needs a lot of carbon dioxide and needs to be kept in the refrigerator for a long time.
Question 6: How to make Shenzhen people's dry ice with dry ice? You can make it yourself. If it works, you can't do it. You have to go to the factory that produces dry ice. You can do this for fun, but the dry ice you make is irregular. You can use a carbon dioxide fire extinguisher, but it won't cost much. Find a cloth bag, open the carbon dioxide fire extinguisher, put the cloth bag tightly at the outlet of the fire extinguisher, and press the handle to release carbon dioxide. There will be dry ice in the cloth bag soon, so be safe.
Question 7: How to make dry ice? Can you do it yourself at home? If carbon dioxide w is added, it will turn white, like snow holding a grave. @ nSolid W can be directly made into dry ice without melting, so it is called "dry ice". Dry ice has a good refrigeration effect, such as making ice cream. "Dry ice" is a good way to protect meat and other perishable foods. When B ship delivers turbid food for H, it can be used to protect some food of r@, and U eggs are decorated with "dry ice" for a limited time. When roses are put in carbon dioxide, buds can be kept for three days. "Dry ice" can be used for artificial rainfall. If it doesn't rain in the south, you can shoot [13] b "dry ice" and pour a pot of heavy rain. @ It's because "dry ice" sucks the curtains and evaporates water into water droplets, causing artificial rainfall. If co2 is added, it will be reduced to solid W and put at a constant altitude, so the dance is basically made of @ dry ice. Co2, CO2, CO2, CO2, CO2, CO2, CO2, CO2, CO2, CO2, CO2, CO2, CO2, CO2, CO2, CO2, CO2, CO2, CO2, CO2, CO2, CO2, CO2, CO2, CO2. "Dry ice" is a good way to protect meat and other perishable foods. When B ship delivers turbid food for H, it can be used to protect some food of r@, and U eggs are decorated with "dry ice" for a limited time. When roses are put in carbon dioxide, buds can be kept for three days. "Dry ice" can be used for artificial rainfall. If it doesn't rain in the south, you can shoot [13] b "dry ice" and pour a pot of heavy rain. @ It's because "dry ice" sucks the curtains and evaporates water into water droplets, causing artificial rainfall. Production of dry ice with liquid carbon dioxide. Dry ice only exists under high pressure. Under normal circumstances, dry ice will sublimate into the atmosphere. In Phoenix's double throat equipment, dry ice particles and compressed air enter the equipment through different throats respectively. Dry ice and compressed air are finally mixed in the nozzle. In single-throat equipment, dry ice particles and compressed air are fully mixed in a single pipe. Carbon dioxide solid, commonly known as dry ice, has a low temperature of 78.5 degrees Celsius, and its cooling capacity is more than 1.5 times that of water ice. After absorbing heat, it sublimates into carbon dioxide gas without any residue, toxicity and smell. Has bactericidal effect. 1, which has been widely used in aviation food preservation. 2, ice cream production, such as brand Haagen-Dazs. Is in use. After adding dry ice, the ice cream is not easy to melt, and the evaporation of dry ice can produce white smoke, which is very charming. 3. High-end restaurants put dry ice in the dishes to create a smoky landscape and improve the banquet level. Like making lobster. In addition, dry ice is added to wine or beverage and adjusted to a proper temperature to make it taste very pure, and the cup is smoky and very pleasant. Unlike water ice added to wine, it will be diluted by melted water. 4. Shrimp, crab, shark fin and other seafood and fish are frozen, because carbon dioxide can inhibit the growth of microorganisms and make them not rot for a long time. Widely used in Europe, America, Japan and other countries. 5. The refrigerated transportation of living cells and microbial specimens in biological laboratories has been adopted by quite a few universities and research institutions in the world. 6. In the preparation of nano-powder, dry ice is the best method to prepare ethane coolant. 7. In the machinery factory, it is more feasible to install the workpiece with dry ice than with liquid nitrogen. 8, greenhouse planting quantitative CO2 system, using dry ice is easy to achieve quantitative and slow release.
Question 8: How to make dry ice (solid carbon dioxide) at home? Buy a carbon dioxide cylinder, find a mold, open the valve head of the carbon dioxide cylinder, pour it into the mold at 45 degrees, and make dry ice.