Laboratory Studies of Gas Tracers for Reaeration

Laboratory studies were conducted to determine the rates at which ethylene and propane desorbed from a water bath relative to the rate at which oxygen was absorbed by the same water. The ratios between the oxygen absorption coefficient and the hydrocarbon desorption coefficient are 1.15 and 1.39 for ethylene and propane, respectively. These ratios serve as the basis for a tracer technique for measuring reaeration coefficients of streams. Comparison of 2-parameter and 3-parameter procedures show that the 3-parameter procedure is able to fit the data better in terms of a root-mean-square error. However, estimates of the saturation concentration for dissolved oxygen with the 3-parameter procedure are unrealistic. Therefore, a 2-parameter procedure with the saturation concentration fixed at a literature value for the specific temperature and corrected for barometric pressure was used. The 2-parameter procedure was also used for the hydrocarbon data with the equilibrium concentration fixed at zero.