| Popis: |
This chapter deals with various aspects of carbon isotope separation. Isotope effect based on a pressure difference of saturated vapors of isotopically substituted carbon-containing molecules is studied. The highest values of the single stage separation factor are typical for two substances—namely, carbon oxide or carbon monoxide (II) CO, and methane CH 4 , for which the available experimental data are the most extensive. The properties of carbon oxide (II) allow direct use of liquid nitrogen as coolant for liquid CO production. The rectification at the liquid nitrogen temperature level necessitates careful preliminary purification of CO from the admixtures of carbon dioxide (IV) CO 2 , oxygen, and water to the ppm grade. It is found that the purification of the source carbon oxide supplied in bottles under a pressure of 15MPa is performed in a trap cooled with waste cold gaseous nitrogen, and then in a rectification purifier of 23 mm diameter and 1.5 m height. It is observed that instead of the pressure increase by the cascade stages leading to a decrease in the separation factor, the pressure in condensers 8–11 of all the columns of the module is taken to be uniform. It is shown that the nitrogen cycle makes it possible to decrease the consumption of liquid nitrogen as heat-transfer medium for the carbon oxide condensation by about half. |
