Investigation of Water-in-Biodiesel Emulsion Characteristics Produced by Ultrasonic Homogenizer

Abstract

Limited studies had been conducted using water-in-diesel emulsion produced from ultrasonic homogenizing method. In this study, Water-in-Biodiesel Emulsions (WiBE) produced using ultrasonic homogenizer were characterized and studied for their physical and chemical properties through various laboratory investigations. The data were then compared with WiBE produced using mechanical homogeniser by the current researchers. Physical characterization tests were carried out on 24 WiBE emulsions produced using an ultrasonic bath, with water percentage of 9%, 12% and 15%, HLB value of 6, 7, 8 and 9, and surfactant dosage of 5% and 10%. The water droplets produced using ultrasonic homogeniser were found to be evenly distributed and generally smaller in size. The density and viscosity values of these emulsions were found to be uniformly larger than WiBE produced using mechanical homogeniser. Emulsions with 15% water exceeded the density threshold, indicating the limits of the amount of water which can be added to the biodiesel fuel. Also, it was found that for viscosity, the HLB is limited to HLB 9 for higher surfactant dosage.

Investigation the Stability of Water in Oil Biofuel Emulsions Using Sunflower Oil

“…HLB is a measure of the balance of the size and strength of the hydrophilic (water-loving) and lipophilic (oil-loving) groups of the surfactant [18]. An HLB of between four and six is the suggested range for the creation of stable W/O emulsions, and it has been suggested that a value outside of this range may not result in an emulsion of this type [13,19]. However, in publications by Mondal and Mandal [6] and Karim, et al [13], W/O emulsions were formed by using surfactants with HLB values of seven, eight and nine.…”

“…An HLB of between four and six is the suggested range for the creation of stable W/O emulsions, and it has been suggested that a value outside of this range may not result in an emulsion of this type [13,19]. However, in publications by Mondal and Mandal [6] and Karim, et al [13], W/O emulsions were formed by using surfactants with HLB values of seven, eight and nine. The discrepancy here could relate to the fact that different oils have been used by researchers when making their emulsions, which may have altered the optimum HLB for their specific system.…”

“…The homogenisation procedure used to emulsify oil and water has been known to affect the size of water droplets formed in W/O emulsions. Emulsification methods that are often compared are mechanical homogenisation and ultrasonication [6,13]. Mechanical homogenisation is the physical process used to reduce the interfacial tension between the two immiscible liquids of an emulsion [13].…”

“…Emulsification methods that are often compared are mechanical homogenisation and ultrasonication [6,13]. Mechanical homogenisation is the physical process used to reduce the interfacial tension between the two immiscible liquids of an emulsion [13]. This is usually executed through the use of a stirrer, as shown in [6].…”

“…The performance of potential fuels can be improved and NO x emissions can be reduced with the addition of water to form water in oil (W/O) emulsions [6][7][8][9][10]. However, water in oil emulsions will likely increase engine corrosion, which has been attributed to the higher acidity of emulsified fuel due to utilizing surfactants [11,12] and an increase of the fuel viscosity [13], which reduces the tendency of fuel breakup and atomization. An emulsion is a mixture of liquids that are immiscible with each other, and will eventually separate into individual phases [14].…”