Industrial carbon dioxide

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Introduction to the New Project for Building a CO2 Facility with an Annual Production Capacity of 20,000 tons per year, Meeting New National Standards 1 Physical and Chemical Properties Carbon dioxide (CO2) is one of the more abundant chemical substances; its sources include natural sources as well as those generated during chemical reactions. CO2 exists in three physical states: gas, liquid, and solid. Under normal temperature and pressure, it is a colorless gas with a slight acidic taste. Under standard conditions, one cubic meter of CO2 gas weighs 1.9769 Kg. At one standard atmosphere pressure, its sublimation temperature is -78.5°C, its critical temperature is 31.1°C, its critical pressure is 7.3967 Mpa, and its relative molecular mass is 44.01. It cannot burn, is easily liquefied, and its density is 1.53 times that of air. Applying pressure below the critical temperature can liquefy CO2 gas into colorless liquid CO2. 2 Applications: As the fields of application for CO2 continue to expand, the market prospects are becoming increasingly favorable. Based on the mass of CO2 and its intended use, it can be divided into industrial grade and food grade. Depending on the physical state of CO2, it exists in three forms: gaseous, liquid, and solid (dry ice). Industrial-grade CO2 is primarily used in: 1. CO2 gas shielded welding: CO2 gas shielded welding is one of the key technologies being promoted in China’s welding industry, and with an increasing rate of adoption, its annual growth rate is expected to be around 10%. 2. CO2 fire extinguishing systems: As living standards improve, there has been a significant increase in the use of CO2 fire extinguishing systems in hotels, luxury residences, cars, as well as enterprises and institutions. As a result, the consumption of CO2 in fire extinguishing equipment is increasing at a rate of 8–12% per year. 3. CO2 gas fertilizer: CO2 and water are the two basic raw materials for plant photosynthesis, and the industrialization of agricultural production is the only path to agricultural modernization. The establishment of food and vegetable production bases has opened up new avenues for the use of CO2 as a gaseous fertilizer in agriculture, with growth rates expected to exceed 3% as well. Food-grade CO2 is primarily used in: 1. The beverage and beer industry: This industry represents the main market for food-grade CO2. In China, consumption of beverages and beer is much lower than in developed countries, at only 5 kg per person per year, whereas in developed countries such as the United States, it exceeds 150 kg per person per year. As the living standards of the people in our country continue to rise, the demand for food CO2 in this industry is set to grow at a rate of over 20% per year. 2. Tobacco industry: The tobacco industry traditionally used Freon for expanding tobacco shreds. With increasing environmental regulations and stricter requirements regarding food additives, CO2 from the food industry has presented great opportunities for this sector. The use of liquid food-grade CO2 for expanding tobacco shreds allows each box of cigarettes to save 2.5–3.0 kg of raw tobacco shreds, while also improving the quality of the expanded tobacco shreds. Zhejiang Cigarette Factory replaced all its original Freon-based swelling equipment with CO2 swelling equipment in 2001. Assuming an annual production of 30 million cartons, the cigarette industry requires approximately 900,000 tons of CO2 per year. 3. Preservation industry: The promotion of truly green foods has opened up new application areas for the preservation of food, vegetables, fruits, and aquatic products, as well as for pest control and storage of grains. 4. CO2 supercritical extraction technology: As a new type of chemical processing technology, CO2 supercritical extraction technology has achieved breakthrough progress in areas such as traditional Chinese medicine, food, fragrances, petrochemicals, biochemistry, and environmental chemistry, and its usage is also increasing rapidly. 3 Product quality standards: At present, the product quality standards of most carbon dioxide production plants in China can only meet the GB10621-89 standard issued in 1989. In contrast, the liquid carbon dioxide quality standards set by the International Beverage Technology Association (the Coca-Cola standard in the United States) and the newly issued national standard for food-grade carbon dioxide, GB10621-2006, impose strict requirements on total sulfur, total hydrocarbons, moisture, alcohols, benzene, and ethers in the products. For comparative reference, see the table below: Quality specifications for liquid carbon dioxide as set by the International Beverage Technology Association: Parameter | Specification; Purity: ≥ 99.9% v/v; Moisture: ≤ 20 ppm v/v; Acidity: Passes testing; Oxygen: ≤ 30 ppm v/v; Ammonia: ≤ 2.5 ppm v/v; Nitric oxide/diatomic nitrogen: ≤ 1.0 ppm v/v; Non-volatile residues: ≤ 10 ppm w/w; Non-volatile organic residues: ≤ 5 ppm w/w; Phosphine: ≤ 0.3 ppm v/v; Total volatile hydrocarbons (expressed as methane): ≤ 50 ppm v/v, with non-methane hydrocarbons being less than 20 ppm v/v; Acetaldehyde: ≤ 0.2 ppm v/v; Aromatic hydrocarbons: ≤ 0.020 ppm v/v; Carbon monoxide: ≤ 10 ppm v/v; Total sulfur (expressed as S): ≤ 0.1 ppm v/v; Carbon disulfide: ≤ 0.1 ppm v/v; Hydrogen sulfide: ≤ 0.1 ppm v/v; Sulfur dioxide: ≤ 1.0 ppm v/v; Appearance of aqueous solution: Colorless, no visible particles; Odor: No unusual odor; Taste and odor in aqueous solution: No unusual taste or odor in water; Oil: ≤ 5 ppm w/w; Ethylene oxide: ≤ 10 ppm v/v; Methanol: ≤ 10 ppm v/v; Ethanol: ≤ 10 ppm v/v; Benzene: ≤ 0.01 ppm v/v; Dithiols: ≤ 0.1 ppm v/v. Standards GB10621-89: Parameter name | Specification; Carbon dioxide (CO2), (v/v): 99.5%; Moisture