Advances in Water Treatment and Enviromental Management

COLLECTION EFFICIENCY OF LIQUID/LIQUID HYDROCYCLONES 171This equation can be integrated for x=0 to x=L to give the total variation of the concentrationof droplets of diameter d between the inlet of the separation chamber (Ci) and the outlet (Co):with:The collection efficiency of the cyclone for droplets of diameter d is by definition E=1-Co/CiFig.7 gives an example of the efficiency curves calculated with the above expression for thecyclone for the three different flow rates corresponding to the experiments.5 SEPARATION TESTS RESULTSThe theoretical curves of Fig.7 were used to predict the overall collection efficiency of thehydrocyclone from the experimental drop size spectra. These predictions could be comparedwith measurements on oil in water dispersions. Experimental efficiency curves could not beFig. 7 Calculated collection efficiency curvesOil density=840Kg/m3; R0=.03m L=0,6mI: Q=7.7n3/h;Ve=5m/s, 2: Q=6.6m3/h;Ve=4.3m/s; 3; Q:3.3m3/h;Ve:2.1m/sobtained since drop breakup occuring at the outlet orifice modified the spectra obtained atthe end of the separation chamber. The operating conditions, experimental and predictedefficiencies are given on Table I for which the mean inlet drop diameter is defined by: , nibeing the number of droplet of diameter by:, ni being the number of droplet of diameter di.It can be seen that the agreement is good, which seems to validate the simple modellingproposed.