Separation of Oil/Water Emulsions in Continuous Flow Using Microwave Heating

Abstract

This work studies a continuous flow microwave system to enhance gravity settling of water-inoil emulsions. Settling times were found to be dependent upon the applied power, flowrate and energy input. Power and energy input are linked to liquid flowrate within the flow system used in this study, so a key objective of this work was to understand the effect of turbulence on the heating and separation of the flowing emulsion. At high flowrates (9 -12 L/min) it was found that turbulence dominates, with settling times largely independent of energy input. At lower flowrates (1 -6 L/min), when turbulence was decreased, it was found that the settling time decreased as the power density was increased. Settling times have the potential to be less than half that of untreated emulsions, and can be reduced further if turbulence can be minimised between the microwave heating zone and the settling zone in the process equipment.2

Investigation into the mechanisms by which microwave heating enhances separation of water-in-oil emulsions

“…Size distribution of water droplets formed during emulsification for 30% water. Inset image shows the water droplets after thresholding from the background oil using image analysis [14]. Page 24 of 25 …”

“…Lemos et al [11] and Guzmán-Lucero et al [12] investigated the addition of ionic liquids (IL) in conjunction with microwave treatment. Fortuny et al [13] proposed a promising new method for measuring salinity in crude oils that involved a microwave demulsification step and Binner et al [14] evaluated a continuous flow system to assess the impact of industrial processing conditions on microwave enhanced emulsion separation.…”

Demulsification techniques of water-in-oil and oil-in-water emulsions in petroleum industry

“…There is ample evidence indicating the superiority of microwave heating over the conventional heating schemes for breaking emulsions due to faster separation rate and less energy consumption of the former, which themselves are indebted to high penetration power of microwaves enabling the "volumetric" and "selective" heating of the dispersed phase [9,16,65,119,[237][238][239][240][241]. The advantages of microwave heating technology help it to be applied as a standalone pathway for demulsification of emulsions in petroleum industry, by eliminating or minimizing the consumption of chemical demulsifiers [242,243].…”

“…In a continuous system, the settling time depends on the applied microwave power, energy input, and particularly upon the flow rate, since the first two parameters themselves are linked to the flow rate (turbulence). Binner and co-workers [240] established a lab-scale continuous microwave system preceding a settling container for the treatment of a model crude oil emulsion, and discerned that at high flow rates (9-12 L min -1 ), where turbulence is dominant, the settling times were independent of energy input, whereas at low flow rates (1-6 L min -1 ) they decreased upon increasing the power density.…”

Model food for microwave‐assisted pasteurization of fruit juices and nectars at 915 and 2,450 MHz

“…The disadvantage of these systems was the long residence time necessary to reach the desired temperature. With the advent of flow-through single-mode cavities, the heating rate improved and different designs were studied (Binner et al, 2013;Kumar et al, 2008;Sabliov, Boldor, Coronel, & Sanders, 2008;Salvi, Boldor, Aita, & Sabliov, 2011;Steed et al, 2008). Compact cylindrical cavities with coiled tubes were also tested (Matsuzawa, Togashi, & Hasebe, 2011;Tuta & Palazoglu, 2017;Vrba, Jansen, & Tamnjong, 2009), as well as tubular systems with multiple microwave ports (Raaholt, Isaksson, Hamberg, Fhager, & Hamnerius, 2016;Stratakos, Delgado-Pando, Linton, Patterson, & Koidis, 2016).…”