Ultrasonic Based Device to Monitor Oil Separation from Oily Water Discharges

Abstract

Discharges of oily water are common among a number of commercial operations. If unregulated these effluents can lead to both short and long term adverse environmental impacts. Development efforts were undertaken in this study for a robust ultrasonic based device to monitor separation of oil and water from oily water effluents. Most of these separations are carried out in gravity settlers where several problems are encountered. These include periodic temperature variations (often over a 25–50 °C range), changes in composition of the oily phase, and presence of suspended impurities as well as fouling conditions. The device incorporates an innovative low cost self‐correction feature to minimize measurement errors under such difficult and dynamic conditions. This feature allows continuous in‐situ measurement of acoustic velocity, a key parameter required for oil depth measurements, giving accuracy within ±2 %. The development plans moved progressively from proof‐of‐concept to prototype of the device with a systematic strategy to improve reliability and accuracy at each stage. These included selection of appropriate transducer frequency and tests with suspended and settled impurities. After initial evaluations, a device configuration with a transducer mounted on a guided float was recommended for further development efforts. The transducer was placed facing down at the centre of the float designed to move up and down with the liquid level in the tank.

Sistema de Monitoramento Versátil de Conteúdo Líquido Aplicado em Separadores Primários

“…A técnica de pulso eco com a direção do pulso perpendicular ao plano das interfaces (Adamowski et al, 2013) foi aplicada assumindo o conhecimento prévio das propri-edade físicas dos materiais presentes no interior do reservatório (Behnia et al, 2019;Olmos, 2002). A altura da interface no interior do recipiente foi determinada utilizando um provador por ultrassom do tipo pistão plano circular cujo campo acústicoé bem conhecido (Duran et al, 2020…”