The Effect of dispersed phase feed rate on the production of pickering emulsions

Dönmez, Dila
Emulsions are fundamental in many applications such as food, petroleum, detergent, pharmaceutical and cosmetic industries. Pickering emulsions are defined as emulsions of any type, either oil-in water, water-in-oil or even multiple, stabilized by solid particles instead of surfactants. Solid particles may prevent the droplets from coalescing by getting adsorbed at the interface, and thus stabilizing the emulsion. Pickering emulsions have more advantages over emulsions stabilized by surfactants in terms of stability, biocompatibility, environmental risks and cost. There are numerous studies about the effect of oil, water and particle properties, but almost no studies about the effect of processing parameters on the formation of Pickering emulsions in a stirred tank. The literature shows that the feed rate of a second phase into the first one has a significant impact on the mixing process, and therefore the product properties. This also applies to formation of Pickering emulsions: the feed rate of the dispersed phase into the continuous phase may be a critical processing parameter that impacts the final droplet size. In this study, the aim was to investigate the effect of feed rate of the oil phase on the final average droplet size when the following hydrodynamic conditions were constant for all configurations: tip speed, power per mass, impeller Reynolds number. Pickering emulsions were produced by using silicone oil as dispersed phase, distilled water as continuous phase, calcite as an emulsifier in a stirred tank where the feed rate of the vi dispersed phase was varied. The experiments were performed with three different impellers: Rushton turbine (RT), up-pumping pitched blade turbine (PBTU), and down-pumping pitched blade turbine (PBTD). All the impellers were tested at two different sizes, T/3 and T/2 where T is the tank diameter. The droplet diameters were measured in Mastersizer® 3000 (Malvern) which is a particle size analyzer. In summary, it was found that the decrease in feed rate causes reduction in the average droplets size due to smaller newly generated droplets and effective particle adsorption. This is only valid if the droplets have not reached the minimum equilibrium size at different hydrodynamic conditions. At lower impeller speeds and feed rates, the effect of feed rate is more pronounced, thereby under these conditions, maximum reduction in the average droplet size is found as 24% with RT-T/3. Besides of the feed rate effect, it was also found that impeller type, impeller size, feeding point and hydrodynamic conditions have an impact on the average droplet size.


Akın, Deniz; Yakar, Arzu; Gündüz, Ufuk (2015-09-03)
Dyes, which are used in different industries such as paper, plastics, leather, pharmaceutical, food, cosmetics, textiles, etc., constitute a major class of environmental pollutants. In recent studies, magnetic adsorbents combining magnetic separation technology with the adsorption process has been used to remove dyes from industrial wastewaters. The main advantages of the adsorbents are possible to be easily and simply separated from process media in a short time using the external magnetic field and will b...
The effect of solids concentration and particle properties on cloud height in tall stirred tanks
Altıntaş, Ezgi; Ayrancı Tansık, İnci; Department of Chemical Engineering (2021-6)
Solid-liquid mixing is one of the most commonly used unit operations in industries such as petrochemicals, polymer processing, biotechnology, pharmaceuticals, and mineral processing. There are two focuses in solid-liquid mixing operations: solids suspension and solids distribution. The key design parameter for solids suspension is Njs. In most solids suspensions, the main objective is to provide maximum contact between solid and liquid phases with minimum power consumption, and this can be achieved by setti...
The effects of microbial lignocellulose pretreatments on xylooligosaccharide production
Uckun, E.; Ak, O.; Bakir, U. (Elsevier BV, 2009-09-01)
Lignocellulosic agricultural waste materials are produced in huge amounts in the world and regarded as abundant, inexpensive readily available natural sources for various industries. They are mainly composed of three types of macromolecules, cellulose, hemicellulose and lignin. Cellulose and hemicellulose are converted to a variety of valuable compounds such as enzymes, hormones, antibiotics, ethanol, sugar alcohols, organic acids and xylooligosaccharides (XOs) using bioprocessing methods easily after the r...
Effect of extraction conditions on hemicellulose yields and optimisation for industrial processes
Celebioglu, Hilal Yilmaz; Çekmecelioğlu, Deniz; DERVİŞOĞLU, MUHAMMET; KAHYAOĞLU, TALİP (2012-12-01)
Hemicellulose is a valuable component of agro-food industrial wastes and used in various areas such as drug manufacture and food industry for encapsulation and emulsification. In this study, effects of raw material type, particle size, and extraction conditions (alkaline concentration, temperature, time) and methods (direct alkaline extraction, alkaline extraction after component removal and acidic extraction method) on hemicellulose yields were investigated. Sugar beet pulp and corn wastes were used as raw...
The effects of emulsifier type, phase ratio, and homogenization methods on stability of the double emulsion
YILDIRIM, Merve; Şümnü, Servet Gülüm; Şahin, Serpil (Informa UK Limited, 2017-01-01)
The double emulsion technology has a potential effect on the development of diversity and quality of functional foods by means of decreasing oil or salt concentration, encapsulating and controlling release of valuable components. In this study, it was aimed to formulate stable double emulsions to be used in food systems. W1/O ratios of primary emulsions, stabilized by polyglycerol polyricinoleate (PGPR), were designed as 2:8 and 4:6, and (W1/O)/W2 ratios of the double emulsions were used as 2:8 and 4:6. W/O...
Citation Formats
D. Dönmez, “The Effect of dispersed phase feed rate on the production of pickering emulsions,” M.S. - Master of Science, Middle East Technical University, 2018.