Detailed explanation of the dry ice manufacturing process: from carbon dioxide to dry ice
August 19, 2023
Dry ice, scientifically known as solid carbon dioxide, plays an important role in all walks of life due to its unique low-temperature properties and wide range of applications. From food preservation to industrial cleaning, dry ice has a variety of uses. So, how is dry ice made? This article will introduce the dry ice manufacturing process in detail and take you through the journey of transformation from carbon dioxide to dry ice.
1. Obtaining carbon dioxide
The raw material of dry ice is carbon dioxide. There are many ways to obtain carbon dioxide, mainly including the following:
– Natural gas refining: During the mining and processing of natural gas, a large amount of carbon dioxide is produced. These carbon dioxides are separated and purified and can be used as raw materials for dry ice production.
– Fermentation process: For example, in fermentation processes such as winemaking and vinegar making, carbon dioxide is a by-product of fermentation. By collecting and purifying these carbon dioxides, they can be used for dry ice production.
– Industrial waste gas treatment: In some industrial production processes, such as fertilizer manufacturing and petroleum refining, a large amount of carbon dioxide waste gas is produced. Through special waste gas treatment equipment, these carbon dioxides can be recovered for dry ice production.
After obtaining carbon dioxide, it needs to be purified to remove impurities and ensure that the purity of carbon dioxide meets the standards for producing dry ice. This step is crucial because impurities affect the quality of dry ice and the efficiency of the production process.
2. Liquefaction of carbon dioxide
The first step in converting carbon dioxide gas into dry ice is liquefaction. Under high pressure conditions, carbon dioxide gas is compressed and cooled to about -57 degrees Celsius to turn it into a liquid state. The liquefaction process is usually carried out in a specially designed high-pressure container. Liquefied carbon dioxide not only greatly reduces its volume, but also makes subsequent storage and transportation more convenient.
Liquefaction equipment usually includes a compressor, a cooling system, and a high-pressure storage tank. The compressor compresses carbon dioxide gas to about 5.7 MPa (megapascals) and reduces the temperature to below -57 degrees Celsius through a cooling system. Under these conditions, carbon dioxide gas will turn into a liquid state.
3. Decompression of liquid carbon dioxide
Liquid carbon dioxide is not stable at normal temperature and pressure, and it needs to be converted into a solid state through a decompression process. The specific operations are as follows:
– Release pressure: Release liquid carbon dioxide from a high-pressure storage tank into a low-pressure environment. Due to the sudden drop in pressure, liquid carbon dioxide will expand rapidly, partially convert into gas, and absorb a lot of heat.
– Desublimation process: In this process, the remaining liquid carbon dioxide will directly condense into a solid state, that is, dry ice. This step is usually carried out in a specially designed decompression chamber to control the ambient pressure and temperature.
– Controlled molding: The dry ice obtained by desublimation is usually fine snow-like or powdery particles. By controlling the parameters of the decompression process, such as the rate of pressure release and the ambient temperature, the size and shape of the dry ice particles can be adjusted.
4. Dry ice molding
Dry ice molding is a key step in the manufacturing process, which directly affects the shape and use effect of the final product. The molding process is mainly achieved by the dry ice pellet machine.
– Working principle of dry ice pellet machine: The dry ice pellet machine compresses snow-like or powdered dry ice into granules or small blocks. The equipment presses the dry ice into the mold through a high-pressure piston to form dry ice pellets of the desired shape. These pellets are usually 3 mm to 16 mm in diameter, and the specific size depends on the design of the mold and the application requirements.
– Equipment features: The dry ice pellet machine is characterized by high efficiency and high degree of automation. The equipment is equipped with a cooling system and a hydraulic system to ensure the stable molding of dry ice under high pressure. Modern dry ice pellet machines are also equipped with automatic control systems that can adjust the size and density of the pellets as needed.
– Application range: Pelletized dry ice is widely used in industrial cleaning, food preservation and transportation. Compared with block dry ice, granular dry ice is more convenient to use, has a more controllable sublimation rate, and is suitable for more application scenarios.
– Quality control: The formed dry ice pellets need to undergo strict quality inspection. The inspection items include the size, density, purity and sublimation rate of the pellets. Ensure that all pellets are uniform and meet the standard requirements.
5. Storage and transportation of dry ice
The storage and transportation of dry ice require special attention because it will quickly sublimate into carbon dioxide gas at room temperature. The following are the key points in storage and transportation:
– Insulated containers: Dry ice is usually stored in specially designed insulated containers. These containers use highly efficient insulation materials, such as polyurethane foam, which can significantly slow down the sublimation process of dry ice.
– Low temperature environment: When conditions permit, try to store dry ice in a low temperature environment, such as a refrigerator or cold storage, to further slow down the sublimation rate.
– Transportation precautions: During transportation, ensure the sealing and insulation effect of the container to avoid exposing the container to high temperature. In addition, special attention should be paid to ventilation, because the carbon dioxide gas produced by sublimation will increase the carbon dioxide concentration in the transportation vehicle and affect safety.
6. Application of dry ice
After understanding the manufacturing process of dry ice, let’s take a look at its wide application. Dry ice is often used in the following fields due to its low temperature characteristics of -78.5 degrees Celsius:
– Food cold chain transportation: Dry ice is used to maintain the freshness of food and prevent corruption, especially in long-distance transportation. Dry ice does not leave any moisture residue and is very suitable for the transportation of frozen food.
– Industrial cleaning: Dry ice cleaning technology uses the physical and chemical reactions of dry ice particles when impacting the surface for efficient and environmentally friendly cleaning. This method does not damage the surface of the equipment and is suitable for cleaning precision equipment.
– Stage effect: The white mist produced when dry ice sublimates is often used for stage and film effects to create a mysterious atmosphere.
– Laboratory research: In the laboratory, dry ice is used for ultra-low temperature freezing and rapid cooling of reactants, and is a common material in many scientific experiments.
– Medical transportation: Dry ice is used to preserve and transport temperature-sensitive pharmaceutical products, such as vaccines and biological samples, to ensure that they remain cold during transportation.
Conclusion
The transformation of dry ice from carbon dioxide to solid state is a complex process involving high pressure, low temperature and condensation. Through the introduction of this article, I hope you have a deeper understanding of the manufacturing process of dry ice. The production of dry ice requires not only advanced equipment and technology, but also strict safety management to ensure product quality and production safety. In the future, with the advancement of technology, the manufacture and application of dry ice will be more extensive and diversified.
START OWNING THIS TECHNOLOGY NOW ！
Contact us today to learn more about our solutions.