The molecular formula of nitrous oxide is N2O, and it has sublimation properties under the pressure and temperature conditions of the air separation device. At atmospheric pressure, its boiling point is higher than that of N2, O2, and Ar. Therefore, during the separation of oxygen and nitrogen, it will be concentrated in liquid oxygen.
The solubility of N2O in water is very low, and it cannot be separated or removed as the processing air passes through air filters, compressors, coolers, and water separators. Most of them will be carried into molecular sieve purifiers, where the adsorption capacity of molecular sieves for N2O is lower than that for CO2. N2O first penetrates the adsorption bed and enters the distillation tower. During the co adsorption process of molecular sieves for hydrocarbons such as H2O, CO2, and C2H2, the processing air is cooled to near liquefaction temperature in the main heat exchanger, and N2O first condenses into a solid, causing air passage blockage.
In the distillation tower, because N2O is a high boiling point component relative to N2, O2, and Ar components, it will dissolve in liquid oxygen, making it impossible to obtain high-purity liquid oxygen and gaseous oxygen products at the bottom of the upper tower. Moreover, when the discharge of liquid oxygen is insufficient, N2O continuously accumulates in the liquid oxygen and solidly precipitates, blocking the main condenser evaporator channel.
In the production of rare gases krypton and xenon, N2O is also concentrated with the concentration of krypton and xenon. This will affect the catalytic combustion of CH4 in crude krypton and xenon, as well as the adsorption of generated water and carbon dioxide using molecular sieves.
Therefore, the air separation equipment is important for removing N2O from the air. A better cleaning method is to find a suitable molecular sieve and remove H2O, CO2, C2H2, and N2O from the processed air through co adsorption in the molecular sieve purifier.
