Decantador contínuo separador água-óleo com camada líquida coalescente assistido por ultrassom.

Abstract

Industrial and transportation processes have significantly contributed to the pollution of water resources with oils, creating an environmental liability known as oily waters. To mitigate adverse environmental impacts, innovative technologies have been developed, highlighting systems for separating free water and oil, as well as water and oil in emulsion. API-type decanters are often used for the separation of free water and oil, generally acting as a secondary phase in the separation process. These systems can operate with or without the use of coalescent plates. However, they face significant challenges when operated in a horizontal configuration with forced flow in the absence of plates. In this study, the efficacy of using the oily phase as a coalescent layer, aided by 40 kHz, 80 kHz e 120 kHz ultrasound, was evaluated in a horizontal benchtop prototype, operating under different Reynolds numbers of turbulence. Experiments conducted with synthetic effluents composed of free water and oil revealed that, with the application of ultrasound and for Reynolds numbers up to 5000, the prototype maintains the fluid coalescent layer stable and effectively retains oil, reducing the drag of free oil droplets by up to twice compared to operation without ultrasonic assistance. For Reynolds numbers above 5000, although complications were observed, these were substantially less than those verified in the configuration without ultrasound. The superior performance of the prototype with an ultrasound-assisted coalescent layer suggests that future control strategies could be developed to ensure the stability of this layer, enabling the adoption of these equipment as the main stage in commercial free water/oil separation systems.