Modeling the effect of dissolved nitrogen and carbon dioxide on the performance of pure oxygen absorption systems
Fisheries Bioengineering Symposium: American Fisheries Society Symposium 10
Colt J;White RJ;
American Fisheries Society
The effects of dissolved nitrogen and carbon dioxide on the performance of a pure oxygen packed column were evaluated with a multicomponent gas-transfer model. Simulation data indicated that the high solubility of carbon dioxide precludes significant desorption under typical column operating conditions. The control of carbon dioxide buildup in intensive culture systems will require use of conventional aeration equipment or chemical treatment. In contrast to the high solubility of carbon dioxide, the solubility of nitrogen (N2) is low. Consequently, dissolved nitrogen can be stripped from solution during the oxygenation process. The transfer of nitrogen from the liquid phase into the gas phase within the contact enclosure substantially reduces oxygen absorption efficiency (mass oxygen absorbed/mass oxygen supplied) and transfer efficiency (mass oxygen absorbed/power input). Nitrogen stripping also acts to control the allowable change in dissolved oxygen across the absorber when regulated by criteria for contactor effluent total dissolved gas pressure. The extent of nitrogen desorption is determined by the concentration of dissolved gases in the influent, column height, oxygen flow rate, and column pressure.