Advances in Water Treatment and Enviromental Management

COLLECTION EFFICIENCY OF LIQUID/LIQUID HYDROCYCLONES 1672–2 LDA measurementA 4 W argon laser was used with the back scattering technique to measure the tangentialvelocities inside the separation chamber. For this purpose, the cylindrical separation chamberwas shaped in a plexiglas block with parallel faces having the same refractive index as water.The optical correction to be brought to the position of the measured point and to the value ofthe interfringe distance was thus of low importance. The water was seeded with aluminiumpowder and it was assumed that the measured mean tangential velocity of these particleswould be similar to that of water.2–3 Oil in water test loopThe loop used for the oil in water separation tests is shown on Fig.2.Fig. 2: Test LoopA dispersion is generated upstream of the cyclone by mixing oil in water coming from separatetanks. The mixing is operated through a specially designed valve allowing the control of themean droplet diameter of the dispersion. The clear water outlet and oil outlet flows of thecyclone are sent to a settling tank which is filled while the tests are run and emptied beforeeach serie of experiments.The drop size spectra are measured by a Malvern 2600D analyser, the opticall cell of which isrefilled by a continuous sampling of the main flow. A typical drop size spectra is given onFig.3. The inlet and clean outlet oil concentration, respectively Ci and Co, are measured fromsamples analysed by the tetrachloride extraction and infrared absorption method.Fig. 3: Drop Size Spectra d = 20 microns