GASEOUS NITROGEN-OXIDE ABSORPTION IN A SIEVE-PLATE COLUMN

Nitrogen oxides were absorbed into dilute nitric acid in a three-stage sieve-plate column. The variables investigated were liquid flow rate, total gas flow rate, partial pressure of nitrogen oxide in the feed gas, acid molarity, and condensable gas (steam) flow rate. The results of the study indicate the importance of three mechanisms in the absorption of gaseous NO, compounds: (1) the absorption of N2O4, which results in the production of liquid HNO3 and HNO2; (2) the dissociation of the liquid HNO2 into HNO3 and gaseous NO; and (3) the gas-phase oxidation of NO to NO2. An interesting aspect of this study was the detrimental effect that liquid nitrous acid has on nitrogen oxide removal efficiency. The removal efficiencies varied between 75 and 90%. © 1979, American Chemical Society. All rights reserved.