Particle Size Of Oil Droplets Research Articles

Flow field analysis and performance evaluation of a mini-hydrocyclone for ultra-low inlet flow rate

It is difficult for hydrocyclone to separate oil-water under the condition of ultra-low inlet flow rate, which commonly exist in the field of energy engineering. Mini-hydrocyclone is an effective technology to solve this problem. The flow field characteristics and oil droplet migration trajectory in the mini-hydrocyclone are the key to guide its efficient work. An innovative mini-hydrocyclone are studied via computational fluid dynamics (CFD) and experiment method. The good separation performance of mini-hydrocyclone for ultra-low inlet flow rate and tiny particle size of oil droplets is verified and analyzed. Furthermore, The distribution of velocity, oil volume fraction and oil migration trajectories in the mini-hydrocyclone are analyzed systematically. The effects of oil droplet size, inlet flow rate and split ratio on the separation performance of mini-hydrocyclone are investigated. The results show that the maximum separation efficiency of the mini-hydrocyclone for 1.0 L/min ultra-low inlet flow rate is 99.98 %, when the split ratio is 30 %, the oil phase volume fraction is 2 %. Moreover, the morphological and distribution of oil core in mini-hydrocyclone are basically consistent between simulation and experiment results, under the conditions of different operating parameters. The minimum error of numerical simulation and experiment results is less than 2.23 %, the accuracy of the numerical simulation method is verified.

Chitooligosaccharide assisted in the construction of pickering high internal phase emulsion near the isoelectric point of porcine plasma protein

Protein-based emulsion products always be challenged due to destabilize the emulsification at the pH range near isoelectric point (pI) of the protein. Herein, chitooligosaccharide (COS) was successfully used to assist porcine plasma proteins (PPP) to construct the high internal phase emulsions (HIPEs) near pI of PPP, and the characteristics and mechanism of the HIPEs was investigated. Particle size of oil droplets in the HIPEs reduced significantly by adding only 0.25% COS, and the PPP-COS composite HIPEs exhibited excellent performance characteristics near pI of PPP, i.e., pH 5.0, including appearance, particle size, apparent viscosity, modulus, 3D printing and stability. PPP and COS combined to form micro-size particles with many positive charges at pH 5.0, and a strong adsorption between PPP and COS was observed at the pH by quartz crystal microbalance with dissipation (QCMD). The pI of PPP shifted increasingly by about 0.5 along with addition of COS, and so no precipitates were formed at pH 5.0 according to the optical density. Hydrophobic interaction and hydrogen bond could be the main forces between PPP and COS based on interaction analysis. The work provided an excellent compound emulsifier with some bioactivities to stabilize the HIPEs near pI of the protein.

Concentrating emulsified oily wastewater by integrated membrane technology.

The effects of operating pressure, feed temperature, oil content of feed solution, and membrane surface flow rate on membrane flux, concentration multiple, and average particle size of oil droplets in the concentrated solution during the single-stage membrane concentration process were investigated. The experimental results show that within a certain operating range, the membrane flux increases with the increase of operating pressure, feed temperature, and membrane surface flow rate, while it decreases continuously with the increase of feed oil content. Optimal conditions for single stage concentration based on membrane flux, concentration factor, and average particle size of oil droplets in the concentrated solution were determined. Then, on the basis of single-stage membrane concentration conditions, three different pore size separation membranes are combined in different ways. After concentration through multi-stage membranes, the particle size of the oil droplets in the concentrate is greater than 20 μm, which is beyond the particle size range of the emulsified oil, and the concentration of the oil in the concentrate is 20-30 times that of the original oil. The method can realize the recovery of oil resources in the emulsified oil-containing wastewater.

Microscopic Visualization Experimental Study on the Effect and Mechanism of Viscosity Reducer on Emulsification of Heavy Oil

Viscosity-reducer flooding is an effective method to improve oil recovery after the water flooding of heavy oil, and water-in-oil emulsion (W/O emulsion) is easily formed during this process. W/O emulsion has a strong ability to improve mobility ratio and block off high permeability layers, which can effectively improve sweep coefficient and enhance oil recovery. The microscopic visual glass model is mainly used to study the microscopic oil displacement mechanism of dilute oil; however, there are few studies on the emulsification mechanism and influencing factors of heavy oil. The purpose of this paper is to study the mechanism of heavy oil emulsification caused by viscosity reducer at the microscopic level, and the effect of emulsification on heavy oil recovery. The visible physical experiments with the glass microscopic models with different permeability and pore sizes were carried out to study the mechanism and main controlling factors of emulsification and the oil displacement effect of viscosity reducer. On this basis, the software was used to calculate the oil recovery in different areas of the model in different flooding stages, which provides a more intuitive understanding of the oil displacement effect of viscosity reducer. The results showed that there are mainly three types of emulsifications between pores: pore throat-breaking emulsification, blind-end emulsification, and pore channel extrusion emulsification. Hence, the mechanism of the three types of emulsifications and the relationship between droplet size with shear stress have been explored. The shear stress increased with the increase of the shear rate, and the oil droplet size in the model decreased with the increase of the shear. The blocking mechanism of pore throat and the shearing action of viscosity-reducer solution are the main mechanisms of viscous oil emulsification between pores. Generally, the particle size of the emulsified oil droplets formed by the blocking action is large, and it is easy to form pore throat emulsion. The particle size of emulsified oil droplets formed by shearing of viscosity-reducer solution is small. When the pore diameter is smaller than the particle size of oil droplets, the mobility of oil droplets between pores is poor, which means the oil droplets easily accumulate at the blind end to form residual oil. From the results of viscosity-reducer flooding experiments, the heavy oil recovery in each area of the model has been significantly improved after viscosity-reducer flooding compared with water flooding, with the recovery factor in the edge area of the model improving by up to 24.22%. The viscosity-reducer solution has a significant displacement effect on the residual oil in the edge area of the model.

Chlorophyll Inhibits the Digestion of Soybean Oil in Simulated Human Gastrointestinal System.

Nowadays, much available processed and highly palatable food such as cream products and fried and convenient food, which usually showed a high energy density, had caused an increase in the intake of dietary lipids, further leading to significant growth in the prevalence of obesity. Chlorophyll, widespread in fruits and vegetables, was proven to have beneficial effects on alleviating obesity. This study investigated the effects of chlorophyll on the digestive characteristics of lipids under in vitro simulated adult and infant gastrointestinal systems. Chlorophyll decreased the release rate of free fatty acid (FFA) during in vitro adult and infant intestinal digestion by 69.2% and 60.0%, respectively. Meanwhile, after gastrointestinal digestion, chlorophyll changed the FFA composition of soybean oil emulsion and increased the particle size of oil droplets. Interestingly, with the addition of chlorophyll, the activity of pancreatic lipase was inhibited during digestion, which may be related to pheophytin (a derivative of chlorophyll after gastric digestion). Therefore, the results obtained from isothermal titration calorimetry and molecular docking further elucidated that pheophytin could bind to pancreatic lipase with a strong affinity of (4.38 ± 0.76) × 107 M−1 (Ka), while the binding site was amino acid residue Trp253. The investigation not only explained why chlorophyll inhibited digestive enzyme activity to reduce lipids digestion but also provided exciting opportunities for developing novel chlorophyll-based healthy products for dietary application in preventing obesity.

Structure and Rheological Properties of Glycerol Monolaurate-Induced Organogels: Influence of Hydrocolloids with Different Surface Charge.

Organogel (OG) is a class of semi-solid gel, entrapping organic solvent within a three-dimensional network, which is formed via the self-assembly of organogelators. In the present study, OG was produced by glycerol monolaurate (GML) as organogelator. The influence of hydrocolloids with different surface charges (chitosan (CS), konjac glucomannan (KGM) and sodium alginate (SA)) on the physiochemical properties of OG was investigated. Rheological studies demonstrated that OG and pure hydrocolloid solution showed shear-thinning behavior. After incorporation of the hydrocolloid, the initial viscosity of OG was lowered from ~100 Pa·s to <10 Pa·s, and then the viscosity increased to more than 100 Pa·s at a low shear rate of 0.1–0.2 s−1, which subsequently decreased with a higher shear rate. OGs in the presence of hydrocolloids still kept the thermo-sensitivity, while the melting point of the OG decreased with the incorporation of hydrocolloids. Hydrocolloid addition greatly shortened the gelling time of the OG from 21 min to less than 2 min. The presence of hydrocolloids increased the particle size of oil droplets in the molten OG. Some aggregation and coalescence of oil droplets occurred in the presence of positive-charged CS and negative-charged SA, respectively. After gelling, the gel structure converted into a biphasic-like network. Hydrocolloids improved the hardness, stickiness and the oil-holding stability of OGs by 18.8~33.9%. Overall, hydrocolloid incorporation could modulate the properties of OGs through their different surface charge properties. These novel OGs have potential as nutrient carriers or low-fat margarine alternatives and avoid the trans-fatty acid intake.

Gelatin enhances the flavor of chicken broth: A perspective on the ability of emulsions to bind volatile compounds

The mechanism of flavor retention in chicken broth from the perspective of gelatin affecting the flavor-binding ability of emulsions was investigated. Results showed that fat was the important reservoir for aroma compounds in the emulsion. The particle sizes of emulsions significantly decreased with prolonged stewing time of gelatin, which was consistent with the results from confocal laser scanning microscopy and interfacial tension. The ability of pre-heated gelatin emulsions to bind volatile compounds with higher hydrophobicity was enhanced. When 0.1% gelatin was added into chicken broth, the total amount of the main volatile compounds (OAV > 1) increased from 458.83 ng/g to 1218.42 ng/g. In summary, the pre-heated gelatin increased the interfacial pressure of water/oil interface, resulting in a smaller particle size of oil droplets, and these further increased the binding area between oil droplets and flavor compounds. This appears to be the mechanism that gelatin enhances the flavor intensity of chicken broth.

Experimental Study on the Effect of High Pressure Micro-jet Parameters on Homogeneity Performance

High-pressure micro-jet homogenization technology is one of the commonly used methods in the preparation of liquid chemicals. The study on the influence of the parameters of high pressure micro jet on the homogeneity of the agential is helpful to improve the efficacy and safety of the agential. In this paper, using high pressure homogenizer as experimental platform, the oil-water emulsion as homogeneous material, the variation law of homogeneous particle size under the conditions of homogeneous pressure, initial temperature and oil / water ratio was studied. The experimental results show that the particle size of oil droplets decreases with the increase of homogenization pressure; the particle size of oil droplets increases with the increase of initial temperature; and the particle size of oil droplets decreases with the decrease of oil/water ratio. The experimental basis is provided to improve the homogeneity of high pressure micro jet homogenizer.

Azelaic Acid Dry Emulsion

Azelaic (AZ) acid is a non antibiotic drug used for an acne treatment. The AZ dry emulsion power was prepared by mixing power of AZ with dry emulsion base. The 20% AZ cream was obtained by addition of water into powder mixture with a ratio of 1:1 by weight. The dry emulsion base consisted of virgin coconut oil with an emulsifier, hydroxyproplymethylcellulose (HPMC). The physical properties of each primary coconut oil emulsion (COE) were evaluated as percent creaming, theirs viscosity and particle sizes. The results were shown that the emulsion system of 7.5% HPMC provided the suitable formulas with oil droplet particle size 1.23 ± 8.15 micrometer and its viscosity of 30405.02 ± 480.58 cps. After drying process, the moisture content of coconut oil dry emulsion (CODE) was 2.94%. The yield percentage of dry powder was 58%. Moreover, the flowability of dry emulsion powder was appeared to be fair (with an angle of repose of 35.35). After dry emulsion powder mixing with 20 % AZ and water, the AZ cream was appeared to be stable for at least one week with no significantly different in pH and amount of AZ. Thus AZ dry emulsion preparation could be used an alternative recipe for acne treatment with good stability during one week after reconstitution.

Microfluidization as a potential technique to modify surface properties of soy protein isolate

Modifications in physicochemical, conformational and emulsifying properties of unheated and preheated soy protein isolates (SPIs) by microfluidization at a specific pressure level (120MPa) were investigated. The heat pretreatment was carried out at temperatures of 75, 85 and 95°C, respectively. The tested properties included protein solubility (PS), surface hydrophobicity (Ho), free sulfhydryl group (SH) and disulfide bond (SS) contents, conformational characteristics, as well as emulsifying properties (e.g. emulsifying ability index (EAI), particle size of oil droplets in the emulsions, creaming index). The results indicated that the microfluidization treatment generally increased PS, Ho, SS content, as well as EAI of both unheated and preheated SPIs, in a preheating temperature dependent way; the treatment also resulted in partial unfolding and denaturation, and even structural re-arrangement of the proteins; the treatment improved the emulsifying efficiency and stability against creaming, but accelerated the bridging flocculation of oil droplets in the preheated-SPI-stabilized emulsions, with higher extent of flocculation observed at higher temperatures of the pretreatment. Size exclusion chromatography and SDS-PAGE analyses confirmed that the microfluidization led to transformation of insoluble aggregates into soluble ones, in which SH/SS interchanges might be involved. The findings suggest that the microfluidization treatment, or in combination with a thermal pretreatment, would be an effective technique to improve surface properties of SPI.

Food Matrix Effects on in Vitro Digestion of Microencapsulated Tuna Oil Powder

Tuna oil, containing 53 mg of eicosapentaenoic acid (EPA) and 241 mg of docosahexaenoic acid (DHA) per gram of oil, delivered as a neat microencapsulated tuna oil powder (25% oil loading) or in food matrices (orange juice, yogurt, or cereal bar) fortified with microencapsulated tuna oil powder was digested in simulated gastric fluid or sequentially in simulated gastric fluid and simulated intestinal fluid. The level of fortification was equivalent to 1 g of tuna oil per recommended serving size (i.e., per 200 g of orange juice or yogurt or 60 g of cereal bar). The changes in particle size of oil droplets during digestion were influenced by the method of delivery of the microencapsulated tuna oil powder. Lipolysis in simulated gastric fluid was low, with only 4.4-6.1% EPA and ≤1.5% DHA released after digestion (as a % of total fatty acids present). After sequential exposure to simulated gastric and intestinal fluids, much higher extents of lipolysis of both glycerol-bound EPA and DHA were obtained (73.2-78.6% for the neat powder, fortified orange juice, and yogurt; 60.3-64.0% for the fortified cereal bar). This research demonstrates that the choice of food matrix may influence the lipolysis of microencapsulated tuna oil.

Effect of phospholipid emulsifiers on physicochemical properties of intravenous fat emulsions and/or drug carrier emulsions

The physicochemical properties of soy bean oil emulsions stabilized with purified egg lecithins (phosphatides) of various concentrations have been examined. The zeta potential of the emulsion droplets and the mean particle size of oil droplets in 10% (w/w) o/w-type emulsion decreased with increasing emulsifier concentration and then levelled off at more than 1.2% (w/w). In rheological measurements, at the initial stage, the viscosity of 10% (w/w) o/w-type emulsion gradually increased with increasing purified egg lecithin concentration, at the next stage, a plateau was reached at about 1.0-1.4% (w/w), and at the final stage, the viscosity curve showed a dramatic increase. These results indicate that emulsions stabilized by purified egg lecithin at more than 1.2% (w/w) are likely to be sufficiently stable.