[Chemical Knowledge]：Properties, uses, upstream and downstream raw materials, storage methods, properties and corresponding uses of carbon dioxide

Carbon dioxide properties

Carbon dioxide (CO₂) is a colorless, odorless gas with a molecular weight of 44.01g/mol and a density of 1.98kg/m³(0°C,1 atm). Under normal temperature and pressure, carbon dioxide is difficult to be compressed, but it can be liquefied under low temperature and high pressure conditions. Carbon dioxide has a high solubility in water to form carbonic acid (H₂ CO), and this solubility property plays an important role in its natural circulation and industrial applications. It has a critical point of 31.1°C and 73.8 atm, above which it cannot liquefy.

Carbon dioxide uses

Carbon dioxide is widely used, covering food, chemical, medical, agricultural and other fields. In the food industry, carbon dioxide is used for the manufacture of carbonated beverages and food preservation; in the chemical industry, carbon dioxide is an important chemical raw material for the production of urea, methanol, etc.; in the medical field, carbon dioxide is used for aeration in laparoscopic surgery to provide Operating space; in agriculture, carbon dioxide is used to increase greenhouse gas application, promote plant photosynthesis, and increase production.

Carbon dioxide upstream feedstock

Major upstream feedstocks for carbon dioxide include fossil fuels (e. g., coal, oil, and natural gas), industrial byproducts (e. g., waste gas from ammonia production), biomass fuels, and carbon dioxide resources in nature. The combustion of fossil fuels is one of the largest sources of carbon dioxide. By burning fossil fuels, a large amount of carbon dioxide is emitted into the atmosphere. Among the industrial by-products, the exhaust gas from the ammonia production process can be treated to obtain pure carbon dioxide.

CO2 Downstream Products

The downstream products of carbon dioxide are rich and diverse, including food-grade carbon dioxide, industrial carbon dioxide, chemical raw materials, dry ice, etc. Food-grade carbon dioxide is mainly used for carbonated beverages and food freezing; industrial carbon dioxide is used for welding protection gas, chemical reaction raw materials, etc.; in the chemical field, carbon dioxide can be used to produce urea, methanol and polycarbonate and other chemical products; dry ice in the cold chain Transportation and cleaning fields have a wide range of applications.

Carbon dioxide storage methods

Carbon dioxide is stored in a variety of ways, including gaseous storage, liquid storage and solid storage. Gaseous storage generally uses high-pressure gas cylinders, which are suitable for small-scale storage; liquid storage requires low-temperature and high-pressure conditions, and generally uses low-temperature storage tanks, which are suitable for large-scale industrial applications; solid storage is dry ice storage, and dry ice is sublimated into gaseous carbon dioxide under normal pressure, Suitable for food freezing and transportation. Underground storage technologies (such as salt cavern storage) are also an important long-term, large-scale CO2 storage method.

Carbon dioxide capture and separation technology

Carbon dioxide capture and separation technology mainly includes chemical absorption method, physical adsorption method and membrane separation method. The chemical absorption method absorbs carbon dioxide in a solvent through a chemical reaction, and then separates it; the physical adsorption method uses a porous material to absorb carbon dioxide, and then desorbs it by heating or decompression; the membrane separation method uses a specific membrane material to select carbon dioxide Permeability is separated. Each method has different efficiency and cost, and is suitable for different industrial conditions.

CO2 Transportation

The transportation modes of carbon dioxide include pipeline transportation, tank truck transportation and cylinder transportation. Pipeline transportation is suitable for large-scale, long-distance transportation of carbon dioxide, often used in carbon dioxide capture and storage projects; tanker transportation is suitable for medium-scale liquid carbon dioxide transportation, high flexibility, commonly used in industrial applications and the food industry; cylinder transportation It is suitable for small-scale, high-purity carbon dioxide transportation, such as laboratory and medical use.

CO2 Environmental Impact

Carbon dioxide, as a greenhouse gas, has an important impact on global climate change. The increase in the concentration of carbon dioxide in the atmosphere is one of the main causes of the greenhouse effect, leading to global temperature rise, sea level rise and climate anomalies. Therefore, reducing carbon dioxide emissions and increasing carbon dioxide capture and utilization have become important strategies to deal with climate change. Technologies and policies such as carbon neutrality and carbon capture and storage (CCS) are being promoted and applied globally.

CO2 Market Outlook

With the global emphasis on environmental protection and sustainable development, the market prospect of carbon dioxide is broad. The development of carbon capture and utilization (CCU) technology provides new applications for carbon dioxide, such as synthetic fuels, chemicals and materials. The establishment of carbon trading markets also provides economic incentives for carbon dioxide emission reduction and capture. In the future, with technological progress and policy promotion, the use and management of carbon dioxide will be more efficient and diversified.

Conclusion

As an important chemical raw material and greenhouse gas, carbon dioxide has a wide range of applications and research values in its properties, uses, upstream and downstream raw materials, storage methods and so on. Through continuous improvement of capture, storage and utilization technology, the application of carbon dioxide in industry, agriculture, environmental protection and other fields will continue to expand. Facing the challenge of global climate change, carbon dioxide management and utilization is not only an important field of scientific and technological progress, but also related to the sustainable development of human society.