Principles of carbon capture and carbon dioxide liquefaction for producing dry ice
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This post was last edited by After extreme misfortune comes good fortune_JFaT8 on 2024-8-7 at 11:56. The chemical absorption method for removing CO2 involves using an alkaline absorbent that comes into contact with flue gas and reacts chemically with CO2 to form unstable salts. These salts, when heated or under reduced pressure, decompose to release CO2, thereby regenerating the absorbent and allowing CO2 to be separated from the flue gas. The typical chemical absorption process involves the flue gas, after pre-treatment, entering the absorption tower and flowing from bottom to top, where it comes into counter-current contact with the absorbent that flows from the top of the tower downward; the carbon-depleted flue gas is then discharged from the top of the absorption tower. The CO2-absorbing agent is the rich liquid; after being heated in the rich-lean liquid heat exchanger, it enters the regeneration tower to release CO2. The CO2 released, along with water vapor, is cooled, and after the water is removed, high-purity CO2 gas is obtained. The absorbent for desorbing CO2 is the lean liquid, which flows out from the bottom of the regeneration tower. After heat exchange with the rich-lean liquid heat exchanger, it enters the absorption tower to cycle and absorb CO2. The captured carbon dioxide is compressed and liquefied to become liquid carbon dioxide, which is stored in storage tanks; as needed, it can be converted into dry ice using dry ice production equipment. VX:cszujn
In the process of liquefying carbon dioxide to produce dry ice, it is first necessary to separate high-purity CO2 gas from flue gas using chemical absorption. Specifically, an alkaline absorbent (such as an amine solution) is used to react with the flue gas to form unstable salts. When these salts decompose under heating or reduced pressure, CO2 is released, regenerating the absorbent. The released CO2 has its water vapor removed after cooling, resulting in high-purity CO2 gas. Subsequently, this highly pure CO2 gas is compressed and cooled to liquefy it. Liquified carbon dioxide can be converted into solid dry ice upon further cooling. This process usually needs to be carried out at very low temperatures (around -78.5 degrees Celsius). Due to the metastable state of dry ice, it can transition directly from a solid state to a gas state, a property that makes it very useful for cooling and transportation. .