APPLICABILITY OF THE SIMPLIFIED MODEL FOR THE CORRELATION OF VAPOR-LIQUID-EQUILIBRIUM IN THE CO2-NH3-H2O SYSTEM

The applicability of the simple empirical model-previously derived by Paunovic et al.1 for correlating the VLE in the concentrated CO2-NH3-H 2O system-to water-rich mixtures, encountered in waste water treatment , has been tested. The new parameters of the model have been evaluated for concentrations of ammonia and carbon dioxide up to 16 and 7 molal respectively, for temperatures from 360 to 393 K, and total pressures up to 0.7 MPa. The limit of model applicability in terms of the minim al molality ratio of ammonia to carbon dioxide is established, and sug gested to be 2.3. In the region of model applicability, the proposed c orrelations fit the experimental phase equilibrium constants of ammoni a and water with average relative errors of 5.7 % and 5.1 % respective ly, and the reaction equilibrium constant with 31 % error.