Evaporation of a volatile solute from an aqueous spray pond

Volatile contaminants in industrial waste or process water may be stripped from the water during cooling in spray ponds. However, a methodology is not known for quantitatively estimating the extent to which such contaminants are transferred to the atmosphere during the cooling process. An experimental program was therefore undertaken in a laboratory scale spray pond in order to provide sufficient data for the test of a simple model of the solute loss process from an aqueous phase, under conditions approximating those occurring in practical systems.

Twenty-five essentially isothermal experimental runs using methanol as solute were made with pool temperatures in the range of 8.0 to 46.0°C. The data yielded correlation coefficients, with a model equation based on a simple mass balance, in all cases of greater than 0.99. Eight of the runs yielded correlation coefficients of 0.999 or greater. It is concluded that the simple model is adequate for estimating volatile solute loss rates from spray ponds of this type.

An empirical correlation is also derived which provides the temperature and nozzle flow rate dependence of the overall mass transfer coefficient-spray surface area product for the methanol-water system.