EVALUATION OF THE ONDA CORRELATIONS FOR MASS-TRANSFER WITH LARGE RANDOM PACKINGS

Although large (greater than or equal to 5 cm) polypropylene packings are frequently used in air stripping towers for environmental applicat ions, few fundamental studies of the mass transfer on these large pack ing designs have been performed. For small packings, previous research has verified that the Onda correlations are valid for environmental a pplications. In this research, experimental data for air stripping wer e obtained using a pilot-scale stripping tower, three test compounds, and four polypropylene packings. Results showed that, in general, Onda is a good predictor of mass transfer for large random packings. Howev er, Onda tended to underpredict mass transfer, with 90% of the data fa lling between a 16.5% overprediction and a 34.0% underprediction of th e observed mass transfer. The underpredictions tended to occur at high gas flow rates and when the gas-film resistance predicted by Onda is large. Further analysis revealed that the functionality of the volumet ric gas loading rate is incorrect in the Onda correlations.