1985 Volume 11 Issue 5 Pages 581-588
The performance of isotope separation of carbon-13 by chemical exchange between carbon dioxide and carbamic acid was studied. The working fluid used in the study was a solution of DNBA, (C4H9) 2NH and n-octane mixture. Factors related to the isotope exchange rate were measured, such as the absorption rate of carbon dioxide into the solution of DNBA and n-octane, the isotope exchange rate and the separation factor in the reaction between CO2 and carbamic acid.
The absorption of CO2 into the working fluid was the sum of chemical absorption by DNBA and physical absorption by n-octane. The absorption of carbon dioxide into the working fluid was negligible at temperatures over 90°C, but increased gradually at lower temperatures. Carbon dioxide was absorbed into DNBA by chemical absorption, and DNBA was converted to carbamic acid by the reaction. The reaction for synthesis and decomposition of carbamic acid was reversible.
The separation factor in equilibrium reached a large value at lower temperatures.
The isotope exchange rate between gas and liquid was proportional to the product of the concentration of carbamic acid and the concentration of CO2 by physical absorption.
The isotope separation of carbon by chemical exchange reaction is better operated under the conditions of lower temperature and higher pressure.
