2019 CSCE Annual Conference - Laval (Greater Montreal) Conference
Dr. Maria Elektorowicz, Concordia University
Sediments from oil refineries consist of a complex mixture of oil, water, sand, mineral matter and metastable emulsions. Separation of phases from water-in-oil emulsion still represents a major challenge in petroleum and oil industries including the minimization of rag layers below supernatant oil to effectively demineralize and dehydrate the resulting waste. In the current research, the efficiency of the electrokinetic separation of oil waste phases has been investigated in presence of titanium dioxide (TiO2) nanoparticles and a synthesized catalyst. Seven lab-scale electrokinetic reactors were operated. Three of the reactors involved the addition of 50, 100 and 200 ppm of Nano TiO2 to the oil sediment prior to electrokinetic separation. Another set of three reactors were used to treat sediment mixed with 50, 100 and 200 ppm of a synthesized catalyst. A control reactor which contained only the oil sediment devoid of any TiO2 nanoparticles and the synthesized catalyst was also operated. For all the reactors, vertical samples were collected at four positions with two sampling points near the anode and cathode, respectively. The samples were subjected to wettability analysis, X-ray photoelectron spectroscopy (XPS), and Thermogravimetric Analysis (TGA). It was observed that the addition of Nano TiO2 and synthesized catalyst significantly improved the water removal and volume reduction capacity of the electrokinetic method. Better performance results were, however, obtained with the synthesized catalyst as compared to the use of TiO2 nanoparticles. In comparison with the control reactor, the optimal water/solid ratio was achieved using 100 ppm of Nano TiO2 (reduction from 52.51 to 3.45), and 200 ppm of engineered catalyst (water/solid ratio from 52.51 to 3.38). Wettability analysis and XPS data showed that the electrokinetic treatment induced a change on the surface of the solids which became more water-wet at the anodic side of the reactors. Sediments impregnated with Nano TiO2 or synthesized catalyst showed higher level of wettability as compared to the control. TGA data also showed a better phase separation during electrokinetic treatment when Nano TiO2 or synthesized catalyst was used. Hence, the synergistic effects of TiO2 or synthesized catalyst with electrokinetic treatment can lead to better phase separation and may reinforce the current applications of the electrokinetic method in treating oil sediments.