Experimental Study and Assessment of Different Measurement Methods of Water in Oil Sludge

Oil sludge, composed of oil, water, and solids, is inevitably generated in numerous petroleum processing operations. Oil sludge samples with a broad range of water contents and of different origins were collected. The aim of this work was to check the capabilities of different analytical techniques to determine the water content of different oil sludge samples. For this purpose, three conventional techniques, Karl Fischer (KF) titration, azeotropic distillation (AD) by the Dean-Stark method, and drying according to proximate analysis were compared with a newly proposed technique based on low-field (1) H-NMR. All AD and nuclear magnetic resonance (NMR) results were within the 95% confidence interval of Karl Fisher titration. The drying method results were highly overes- timated due to volatilization. Quality assessment confirmed the effectiveness of the other three methods and low-field (1) H-NMR was validated as an alternative technique for water determination in all oil sludge samples.