Hydrodynamic destruction of waste emulsions in the process of their separation through ultra-flocculation and micro-flotation

Consistent systematic researches of O/W and G/W emulsions behaviour in turbulent flows under a wide range of Reynolds numbers have disclosed a complex extremal dependence of the aggregation (coalescence) velocity of drops (bubbles) on the amount of dissipated energy epsilon; this dependence cannot be reliably explained in terms of available theories. Based upon derived data a highly efficient technology (and the device for its implementation) for the destruction and separation of waste emulsions has been developed. The emulsion, after the introduction of flocculant into it, is subjected to vigorous hydrodynamic treatment (epsilon = 40 J kg(-1) s(-1)), accompanied by the generation of prime aggregates. Thereupon, microbubbles are introduced into the emulsion, and the intensity of treatment is reduced by two order of magnitude (epsilon = 0.1 J kg(-1) s(-1)), which ensures the rapid development of large flotoaggregates, containing over 10(3) microbubbles and over 10(6) primary drops in each flotoaggregate, that are easily separated in the foam separator due to their inherent high buoyancy. The method described is widely applied for the separation of waste lubricants. (C) 1999 Elsevier Science B.V. All rights reserved.