scholarly journals Rotating Membrane Emulsification for Producing Single and Multiple Emulsions

2018 ◽  
Vol 156 ◽  
pp. 08001
Author(s):  
Nita Aryanti ◽  
Richard A. Williams
Keyword(s):  
Droplet Size ◽  
Flow Rate ◽  
Droplet Diameter ◽  
Dispersed Phase ◽  
Membrane Emulsification ◽  
Tubular Membrane ◽  
Emulsion Droplets ◽  
Low Viscosity ◽  
Emulsion Formulation ◽  
Novel Concept

Membrane emulsification is a technique utilising a novel concept of generating droplet ‘drop by drop’ to produce emulsions. The technique has several distinctive advantages over the conventional emulsification techniques.This paper concerns on the development of membrane emulsification (Rotating Membrane Reactor, RMR) which utilizes rotating tubular membrane to initiate droplet detachments. The RMR uses a rotating stainless steel tubular membrane with laser drilled pores (100 μm pore diameter) and a syringe pump to drive the dispersed phase through the membrane at a given flow rate. O/W formulations were prepared with low viscosity of paraffin wax, two types of emulsifiers, different membrane rotation rate and dispersed phase flow rate. The emulsion droplets exhibited a coefficient of variation of 9% and 81μm droplet size. In this research, the pore size/droplet size ratio could achieve 0.8. This value was below than other membrane emulsification processes. The effects of principal system operating parameters on both the average droplet diameter and droplet uniformity were discussed. In addition, a multiple (W/O/W) emulsion formulation was investigated as well.

Water Quality and Well Injectivity: Do Residual Oil-in-Water Emulsions Matter?

SPE Journal ◽  
2010 ◽  
Vol 15 (02) ◽  
pp. 557-568 ◽  
Author(s):  
S.. Buret ◽  
L.. Nabzar ◽  
A.. Jada
Keyword(s):  
Porous Media ◽  
Droplet Size ◽  
Flow Rate ◽  
Produced Water ◽  
Droplet Diameter ◽  
Flow In Porous Media ◽  
Water Emulsion ◽  
Oil In Water ◽  
Emulsion Flow ◽  
Limiting Value

Summary The present work is a part of a thorough and systematic laboratory study of oil-in-water emulsion flow in porous media that we have undertaken recently to investigate the mechanisms of oil-droplet retention and its consecutive effect on permeability. One of our main objectives was to see how the in-depth propagation of produced- water (PW) residual dilute emulsion could impair the permeability during PW reinjection (PWRI). During this casework, we used granular packs of sharp-edged silicon carbide grains and stable and dilute dodecane-in-water emulsions. The flow experiments were performed under well-controlled conditions, and we studied the effect of most of the relevant parameters, including flow rate, salinity, droplet size, and permeability of the porous medium. A careful monitoring of the salinity and the jamming ratio (JR) allowed us to consider and work separately on the two main mechanisms of droplet capture (i.e., surface capture and straining capture). In a previous paper (Buret et al. 2008), we reported on the effect of salinity and flow rate on emulsion flow through porous media where the pore-size/droplet-size ratio (JR) was very high, ensuring that only droplet capture on pore surface is operative. This paper reports on the effect of salinity and JR on both mechanisms, with the main focus being on the induced permeability impairment. We demonstrated that surface capture could induce significant in-depth permeability losses even at a high JR. The maximum reached permeability loss is very sensitive to salinity and flow rate (shear-thinning effect). This maximum is always lower than a limiting value dictated by the surface-coverage jamming limit of random sequential adsorption (RSA) theory. This limiting value increases while decreasing the JR, according to a simple formula extracted from Poiseuille's law with a mean hydrodynamic thickness of the deposited layer close to the droplet diameter (monolayer deposition). Regarding the straining capture, we determined a critical JR of 7 for this mechanism to occur. Preliminary results using only two JR values and one flow rate are presented. Compared to surface capture, the results show that straining capture induces more severe plugging with a lower rate of propagation. The lower the JR is, the more severe the plugging is and the lower the propagation rate is. However, more investigations are still required, notably using various JRs and flow rates to characterize this important mechanism better.

Investigation on the Droplet Formation Time With Xanthan Gum Solutions at a T-Junction

2012 ◽  
Author(s):  
Zhipeng Gu ◽  
Jong-Leng Liow ◽  
Guofeng Zhu
Keyword(s):  
Flow Rate ◽  
Xanthan Gum ◽  
Critical Concentration ◽  
Droplet Diameter ◽  
Droplet Formation ◽  
Continuous Phase ◽  
Formation Time ◽  
Drop Formation ◽  
Dispersed Phase ◽  
Phase Flow

Xanthan gum solutions with various concentrations were used as the dispersed phase to study the formation time for drop formation at a T-junction. Two critical concentrations (0.05 and 0.2 wt%) of xanthan gum solutions were observed resulting in three distinct regimes. The droplet diameter increased with increasing xanthan gum concentration within each regime but the transition through each critical concentration was accompanied by a significant reduction in the droplet size. Experimental results showed that the droplet formation time decreased exponentially with increasing continuous phase flow rate. It was also found that the formation time was reduced with increasing dispersed phase flow rate. Xanthan gum solutions with a higher concentration within each regime resulted in a longer formation time, and there was a decrease in the formation time at each critical concentration. The formation time consists of growth and breakup stages and the effect of xanthan gum concentration on each stage was examined.

Computational Investigation of Microdroplet Formation in a Crossflow Membrane Emulsification Process

2011 ◽  
Author(s):  
Manabendra Pathak
Keyword(s):  
Surface Tension ◽  
Flow Rate ◽  
Viscosity Ratio ◽  
Period Doubling ◽  
Continuous Phase ◽  
Inertia Force ◽  
Dispersed Phase ◽  
Phase Flow ◽  
Membrane Emulsification ◽  
Emulsification Process

Monodisperse microdroplets are formed, when a liquid is injected through a micropore into another immiscible liquid. Depending on the relative flow between the two phases, droplets may form in quiescent, coflowing and crossflowing environment. The dispersions of one phase liquid in another crossflowing liquid are observed in liquid emulsification process and the system has been used extensively in microfluidic devices to produce monodisperse microdroplets with controllable size. Liquid emulsions are widely used in food, cosmetics, pharmaceutics and polymer industries. In the present work, microdroplet formation in a crossflow membrane emulsification process has been investigated computationally using VOF/finite volume method. The full transient simulation has been carried out starting from the injection of dispersed phase to breakup into drops for different values of dispersed phase and continuous phase flow rate, surface tension and viscosity ratio of both the phases. Depending upon the values of the both phases, the droplet formation process shows the dripping and jetting behavior. The qualitative features of the two regimes and their transition have been correlated with different non-dimensional numbers such as Capillary number, Weber number and viscosity ratio of the two phase liquids. Some interesting nonlinear behavior such as period doubling been observed near the transition between the dripping and jetting regimes has. The topological characteristics of dripping, jetting and transition regimes in membrane emulsification have been observed different than in the cases of T-junction emulsification and flow focusing emulsification. Two ways of dripping to jetting transition have been observed, one with the increasing dispersed phase flow rate at constant continuous phase flow rate and other way is reducing the surface tension at constant dispersed phase flow rate. The effect of inertia force has been observed negligible for high value of surface tension and significant for lower surface tension value.

Effect of Shear and Water Cut on Phase Inversion and Droplet Size Distribution in Oil–Water Flow

2018 ◽  
Vol 141 (3) ◽  
Author(s):  
Mo Zhang ◽  
Ramin Dabirian ◽  
Ram S. Mohan ◽  
Ovadia Shoham
Keyword(s):  
Size Distribution ◽  
Droplet Size ◽  
Phase Inversion ◽  
Droplet Size Distribution ◽  
Continuous Phase ◽  
Dispersed Phase ◽  
Water Emulsion ◽  
Inversion Region ◽  
Oil Water ◽  
Water Cut

Oil–water dispersed flow occurs commonly in the petroleum industry during the production and transportation of crudes. Phase inversion occurs when the dispersed phase grows into the continuous phase and the continuous phase becomes the dispersed phase caused by changes in the composition, interfacial properties, and other factors. Production equipment, such as pumps and chokes, generates shear in oil–water mixture flow, which has a strong effect on phase inversion phenomena. The objective of this paper is to investigate the effects of shear intensity and water cut (WC) on the phase inversion region and also the droplet size distribution. A state-of-the-art closed-loop two phase (oil–water) flow facility including a multipass gear pump and a differential dielectric sensor (DDS) is used to identify the phase inversion region. Also, the facility utilizes an in-line droplet size analyzer (a high speed camera), to record real-time videos of oil–water emulsion to determine the droplet size distribution. The experimental data for phase inversion confirm that as shear intensity increases, the phase inversion occurs at relatively higher dispersed phase fractions. Also the data show that oil-in-water emulsion requires larger dispersed phase volumetric fraction for phase inversion as compared with that of water-in-oil emulsion under the same shear intensity conditions. Experiments for droplet size distribution confirm that larger droplets are obtained for the water continuous phase, and increasing the dispersed phase volume fraction leads to the creation of larger droplets.

scholarly journals Research and Development of a 3D Jet Printer for High-Viscosity Molten Liquids

Micromachines ◽  
2018 ◽  
Vol 9 (11) ◽  
pp. 554
Author(s):  
Yang Yang ◽  
Shoudong Gu ◽  
Jianfang Liu ◽  
Hongyu Tian ◽  
Qingqing Lv
Keyword(s):  
Liquid Velocity ◽  
New Technology ◽  
Droplet Diameter ◽  
Average Diameter ◽  
High Viscosity ◽  
Taper Angle ◽  
Voltage Difference ◽  
Low Viscosity ◽  
Cooling Mechanism ◽  
Molten Liquid

Micro-droplet jetting manufacture is a new 3D printing technology developed in recent years. Presently, this new technology mainly aims at ejecting a low-viscosity medium. Therefore, a device for ejecting high-viscosity molten liquid is designed by analyzing the injection principle of high-viscosity molten liquid. Initially, the cooling mechanism is designed to overcome the defect that the piezoelectric stacks cannot operate in high-temperature conditions. Thereafter, the mathematical model of the liquid velocity in the nozzle is derived, and the factors influencing injection are verified by Fluent. Subsequently, a prototype of the jet printer is fabricated, and the needle velocity is tested by the laser micrometer; the relationship between voltage difference and the needle velocity is also obtained. The experimental results matched the theoretical model well, showing that the voltage difference, needle radius, nozzle diameter, and taper angle are closely related to the injection performance of the 3D jet printer. By using a needle with a radius of 0.4 mm, a nozzle with a diameter of 50 μm, a taper angle of 90°, a supply pressure of 0.05 Mpa, and a voltage difference of 98 V, a molten liquid with a viscosity of 8000 cps can be ejected with a minimum average diameter of 275 μm, and the variation of the droplet diameter is within ±3.8%.

scholarly journals Numerical Simulation of Decontamination of Airborne Fission Products during In-Vessel Release Phase by Containment Spray

2018 ◽  
Vol 2018 ◽  
pp. 1-19
Author(s):  
Khurram Mehboob
Keyword(s):  
Droplet Size ◽  
Failure Time ◽  
Ph Value ◽  
Removal Rate ◽  
Droplet Diameter ◽  
Fission Products ◽  
Product Release ◽  
Spray System ◽  
Spray Solution ◽  
Proposed Model

The containment spray system (CSS) has a significant role in limiting the risk of radioactive exposure to the environment. In this work, the optimal droplet size and pH value of spray water to prevent the fission product release have been evaluated to improve the performance of the spray system during in-vessel release phase. A semikinetic model has been developed and implemented in MATLAB. The sensitivity and removal rate of airborne isotopes with the spray system have been simulated versus the spray activation and failure time, droplet size, and pH value. The alkaline (Na2S2O3) spray solution and spray water with pH 9.5 have similar scrubbing properties for iodine. However, the removal rate from the CSS has been found to be an approximately inverse square of droplet diameter (1/d2) for Na2S2O3 and higher pH of spray water. The numerical results showed that 450 μm–850 μm droplet with 9.5 pH and higher or the alkaline (Na2S2O3) solution with 0.2 m3/s–0.35 m3/s flow rate is optimal for effective scrubbing of in-containment fission products. The proposed model has been validated with TOSQAN experimental data.

Evaluation of Models for Droplet Shear Effect of Centrifugal Pump

2018 ◽  
Author(s):  
Ramin Dabirian ◽  
Shihao Cui ◽  
Ilias Gavrielatos ◽  
Ram Mohan ◽  
Ovadia Shoham
Keyword(s):  
Experimental Data ◽  
Size Distribution ◽  
Centrifugal Pump ◽  
Droplet Size ◽  
Separation Efficiency ◽  
Droplet Diameter ◽  
Droplet Size Distribution ◽  
Production Equipment ◽  
Transportation Equipment ◽  
Log Normal

During the process of petroleum production and transportation, equipment such as pumps and chokes will cause shear effects which break the dispersed droplets into smaller size. The smaller droplets will influence the separator process significantly and the droplet size distribution has become a critical criterion for separator design. In order to have a better understanding of the separation efficiency, estimation of the dispersed-phase droplet size distribution is very important. The objective of this paper is to qualitatively and quantitatively investigate the effect of shear imparted on oil-water flow by centrifugal pump. This paper presents available published models for the calculation of droplet size distribution caused by different production equipment. Also detailed experimental data for droplet size distribution downstream of a centrifugal pump are presented. Rosin-Rammler and Log-Normal Distributions utilizing dmax Pereyra (2011) model as well as dmin Kouba (2003) model are used in order to evaluate the best fit distribution function to simulate the cumulative droplet size distribution. The results confirm that applying dmax Pereyra (2011) model leads to Rosin-Rammler distribution is much closer to the experimental data for low shear conditions, while the Log-Normal distribution shows better performance for higher shear rates. Furthermore, the predictions of Modified Kouba (2003) dmin model show good results for predicting the droplet distribution in centrifugal pump, and even better predictions under various ranges of experiments are achieved with manipulating cumulative percentage at minimum droplet diameter F(Dmin).

scholarly journals Model based decision support system of operating settings for MMAT nozzles

2016 ◽  
Vol 56 (2) ◽  
pp. 178-185 ◽  
Author(s):  
Bradley Keith Fritz ◽  
Zbigniew Czaczyk ◽  
Wesley Clint Hoffmann
Keyword(s):  
Decision Support ◽  
Experimental Design ◽  
Decision Support System ◽  
Droplet Size ◽  
Flow Rate ◽  
Support System ◽  
Computational Models ◽  
Ease Of Use ◽  
Size Spectrum ◽  
Orifice Size

Abstract Droplet size, which is affected by nozzle type, nozzle setups and operation, and spray solution, is one of the most critical factors influencing spray performance, environment pollution, food safety, and must be considered as part of any application scenario. Characterizing spray nozzles can be a timely and expensive proposition if the entire operational space (all combinations of spray pressure and orifice size, what influence flow rate) is to be evaluated. This research proposes a structured, experimental design that allows for the development of computational models for droplet size based on any combination of a nozzle’s potential operational settings. The developed droplet size determination model can be used as Decision Support System (DSS) for precise selection of sprayer working parameters to adapt to local field scenarios. Five nozzle types (designs) were evaluated across their complete range of orifice size (flow rate*) and spray pressures using a response surface experimental design. Several of the models showed high level fits of the modeled to the measured data while several did not as a result of the lack of significant effect from either orifice size (flow rate*) or spray pressure. The computational models were integrated into a spreadsheet based user interface for ease of use. The proposed experimental design provides for efficient nozzle evaluations and development of computational models that allow for the determination of droplet size spectrum and spraying classification for any combination of a given nozzle’s operating settings. The proposed DSS will allow for the ready assessment and modification of a sprayers performance based on the operational settings, to ensure the application is made following recommendations in plant protection products (PPP) labels.

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