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).

Fluid Flow Phenomena and Droplet Size Distribution Along the Feed Spreader of Large Oil/Water Tank Separators

2009 ◽  
Author(s):  
Jose G. Severino ◽  
Luis E. Gomez ◽  
Steve J. Leibrandt ◽  
Ram S. Mohan ◽  
Ovadia Shoham
Keyword(s):  
Size Distribution ◽  
Droplet Size ◽  
Separation Efficiency ◽  
Droplet Size Distribution ◽  
Separation Performance ◽  
Water Tank ◽  
Water Dispersion ◽  
Flow Phenomena ◽  
Oil Water ◽  
The Impact

Large gravity separation tanks play an essential role in crude oil production in many fields worldwide. These tanks are used to separate water from an oil-rich stream before safely returning it to the environment. The oil/water dispersion enters the tanks through a feed spreader consisting of an array of pipes with small effluent nozzles. A major challenge is being able to predict oil/water dispersion distribution along the spreader as well as, the maximum water droplet size exiting through the effluent nozzles, under a given set of conditions. The capacity of the studied tank is 80,000 barrels (12,719 m3). Current feed stream is about 60,000 bpd (9,540 m3/day) of wet crude containing about 20% water by volume. A significant increase in flow rates and water volume fraction is anticipated [7], as more wells are added and existing ones mature. This work is aimed at investigating the separation performance of these tanks under current and future flow conditions; focusing primarily on the flow phenomena and droplet size distribution inside the spreader. The main objective is then to identify the impact of the spreader’s geometry and piping configuration on flow behavior and tank’s separation efficiency. The final product provides key information needed for mechanistic modeling the tank separation performance and optimizing tank components’ design. The feed spreader is simulated using Computational Fluid Dynamics (CFD) to assess oil/water flow distribution inside the network. Droplet size distribution along branch-pipes effluent nozzles in, including droplet breakup and coalescence has been studied using the Gomez mechanistic model [2] with input from CFD results. An experimental investigation of the spreader using a scaled prototype was also conducted to better understand flow phenomena and verify the CFD models. Results confirm the occurrence of significant maldistribution of the water and oil phases along the spreader that could impair separation efficiency.

scholarly journals Dinamika tetes dalam kolom isian

2018 ◽  
Vol 7 (1) ◽  
pp. 710
Author(s):  
Danu Ariono ◽  
Dwiwahju Sasongko ◽  
Priyono Kusumo
Keyword(s):  
Mass Transfer ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Size Distribution ◽  
Droplet Size ◽  
Droplet Diameter ◽  
Mass Transfer Rate ◽  
Packed Column ◽  
Droplet Size Distribution ◽  
Droplet Dynamics

To date, evaluation of the performance of liquid-liquid extraction in packed columns has not been able to produce satisfactory results, because the correlations used in this evaluation are empirical in nature, with a very limited range of validity. One of the causes of this limitation is the use of the assumption that the dynamics of liquid dispersed in droplets is constant (in terms of shape, dimensions, and numbers), so that the mass transfer interfacial area and mass transfer coefficient in the column are assumed to be constant. In reality, dynamics of droplets in a column is not constant, due to the imbalance between droplet coalescence and disintegration. For a given droplet diameter, there is an increase in numbers of droplets due to coalescence of smaller droplets, and a  decrease in numbers of droplets due to disintegration into smaller droplets. These coalescence and disintegration phenomena may be caused by various factors, including the existence of packings which impede the flow of droplets. These phenomena impact the mass transfer rate from continuous to dispersed phase, and vice versa, due to a variation in the interfacial contact area and mass transfer coefficient. The observation of droplet dynamics from droplet formation until its motion through void spaces between packings is a critical factor in developing a model that can describe the performance of the packed column. The dynamics of droplets is influenced by various operational and physical variables.  A droplet dynamics experiment has been undertaken, aimed at obtaining the droplet size distribution at specific heights along the column. This distribution is to be used to develop mass transfer coefficient correlations in the continuous and dispersed phases.Keywords: droplet size distribution, packed column Abstrak Evaluasi unjuk kerja ekstraksi cair-cair dalam kolom isian (packed column) hingga saat ini belum dapat memberikan hasil yang memuaskan karena korelasi-korelasi yang  digunakan  masih  bersifat  empiris serta daerah keberlakuannya sangat terbatas. Salah satu penyebab keterbatasan berlakunya korelasi tersebut ialah penggunaan anggapan bahwa dinamika cairan yang terdispersi dalam bentuk tetesan bersifat konstan (bentuk, ukuran serta jumlahnya), sehingga harga luas perpindahan massa dan harga koefisien perpindahan massa dalam kolom dianggap tetap. Kenyataannya dinamika tetesan dalam kolom tidak konstan akibat adanya tetesan yang bergabung dan pecah dalam jumlah yang  tidak sama. Pada suatu harga diameter tetesan tertentu, ada penambahan jumlah tetesan akibat penggabungan tetesan­ tetesan yang ukurannya lebih kecil serta adanya pengurangan jumlah tetesan akibat pecahnya tetesan menjadi tetesan-tetesan yang lebih kecil. Peristiwa penggabungan dan pemecahan tetesan dapat disebabkan berbagai faktor temasuk adanya isian yang menghalangi gerakan tetesan. Kejadian tersebut akan mempengaruhi laju proses perpindahan massa dari fasa kontinyu ke fasa  terdispersi  atau sebaliknya, karena adanya variasi luas permukaan kontak serta koefisien perpindahan massanya. Pengamatan dinamika tetesan mulai saat pembentukan tetes hingga pergerakannya saat melewati sela-sela isian merupakan faktor penting dalam  membangun model  yang  dapat menggambarkan unjuk kerja kolom isian. Dinamika tetesan tersebut dipengaruhi oleh berbagai variabel operasi dan variabel fisik. Eksperimen dinamika fetes yang dilakukan diarahkan untuk memperoleh distribusi ukuran tetes pada posisi ketinggian tertentu dan distribusi tersebut akan digunakan untuk pengembangan  korelasi koefisien perpindahan massa difasa  dispersi danfasa kontinyu.Kata kunci: distribusi ukuran tetes, kolom isian.

Oil plume simulations: Tracking oil droplet size distribution and fluorescence within high-pressure release jets

2017 ◽  
Vol 2017 (1) ◽  
pp. 1230-1250
Author(s):  
R.N. Conmy ◽  
B. Robinson ◽  
T. King ◽  
M. Boufadel ◽  
S. Ryan ◽  
...  
Keyword(s):  
Water Temperature ◽  
Size Distribution ◽  
Droplet Size ◽  
Oil Spill ◽  
Droplet Diameter ◽  
Performance Testing ◽  
Droplet Size Distribution ◽  
Optical Measurements ◽  
Total Petroleum Hydrocarbons

ABSTRACT Optical measurements have been used during oil spill response for more than three decades to determine oil presence in slicks and plumes. Oil surveillance approaches range from simple (human eyeball) to the sophisticated (sensors on AUVs, aircraft, satellites). In situ fluorometers and particle size analyzers were deployed during the Deepwater Horizon (DWH) Gulf of Mexico oil spill to track shallow and deep subsea plumes. Uncertainties regarding instrument specifications and capabilities during DWH necessitated performance testing of sensors exposed to simulated, dispersed oil plumes. Seventy-two wave tank experiments were conducted at the Bedford Institute of Oceanography. Simulated were oil releases with varying parameters such as oil release rate, oil temperature (reservoir temp ~ 80 °C), water temperature (<8 °C and >15 °C), oil type, dispersant type (Corexit 9500 and Finasol OSR52) and dispersant to oil ratio (DOR). Plumes of Alaskan North Slope Crude (ANS), South Louisiana Crude (SLC) and IFO-120 oils were tracked using in situ fluorescence, droplet size distribution (DSD), total petroleum hydrocarbons (TPH) and benzene-toluene-ethylbenzene-xylene (BTEX). For the lighter SLC, bimodal droplet size with mean diameter < 70 μm was achieved for 1:20 and 1:100 DOR, regardless of water temperature. Similarly, the medium ANS crude exhibited mean droplet diameter <70 μm, but was bimodal only for the 1:20 treatment. Bimodal distribution was not achieved with the heavy IFO, but droplet < 70 μm were observed for 1:20 warm waters, indicating poor dispersibility of the high viscosity oil even for jet releases. Results offer valuable information on the behavior and dispersibility of oils over a range of viscosity, DOR and environmental conditions. Findings have implications for fate and transport models, where DSD, chemistry and fluorescence are all impacted by release variables. This research was supported by the Bureau of Safety and Environmental Enforcement.

Numerical Simulation for Prediction of Wetness Content in Wet Steam for Convergent - Divergent Nozzle

2017 ◽  
Vol 2 (1) ◽  
pp. 1-10
Author(s):  
HUSSEIN WHEEB MASHI
Keyword(s):  
Size Distribution ◽  
Droplet Size ◽  
Research Output ◽  
Scattered Light ◽  
Droplet Diameter ◽  
Light Attenuation ◽  
Droplet Size Distribution ◽  
Scattering Method ◽  
Wet Steam ◽  
Matlab Program

     This research is to find a wetness using the (laser beam) optical Forward Scattering Method (F.S.M.) which is applicable to calculate the wetness in a convergent-divergent De-Laval steam nozzle operating (1.3 Mach number) which may be works at wet steam with pressure (1) bar and temperature (373) K .The light source of He-Ne laser of wave light (λ=0.632) µm was used to prediction the wetness in nozzle a wet steam flow. Both  droplet diameter of water (Dr) and relation of intensity of light S= /  are assumed to be (Dr=10,30,50,70,100 µm) and (S = 0.9,.0.8,0.7,0.6,0.5 )  respectively. From the relation of light intensity pattern of many diameter droplet of water (Dr) and different droplet size distribution N (Dr), the MATLAB program can calculate the light attenuation coefficient (Ks) consequently. The increase of the droplet size distribution, N (Dr), leads to decrease the values of (S) and (Ks). The increase of the droplet diameter causes increase of the scattered light, and the minimum value of scattering light is with (Dr= 10µm) for the tested samples. The wetness of steam (yₒ) = (1,3,557,10) % ,which depend on the [Dr, N(Dr)] in the scattered zone  can be determined easily by the MATLAB program. The radius of droplet water in two – phase can be adversely calculated by using the research output that then the concentrations or wetness is previously specified.                                                                                        

Droplet Size Distributions and Pressure Control in the Gas-Liquid Cylindrical Cyclone

2020 ◽  
Author(s):  
Lele Yang ◽  
Jing Wang ◽  
Li Zou
Keyword(s):  
Size Distribution ◽  
Droplet Size ◽  
Separation Efficiency ◽  
Flow Instability ◽  
Droplet Size Distribution ◽  
Pressure Control ◽  
Superficial Velocity ◽  
Liquid Level ◽  
Outlet Section ◽  
Cylindrical Cyclone

Abstract The gas–liquid cylindrical cyclone (GLCC) employs gravitational and centrifugal forces to realize gas-liquid separation. The aim of this study is to understand the droplet size distribution and pressure control in the GLCC via experiment and numerical analysis. The droplet size and pressure distributions were measured using Malvern RTsizer and pressure transmitters, respectively. The Discrete Phase Model was used to numerically analyze the swirling hydrodynamics of the GLCC. The results showed that the increase in the gas superficial velocity decreased the droplet size distribution at the inlet as a whole due to the shear effect and flow instability. The increase in the liquid superficial velocity only increased the small droplet size distribution at the inlet for the limitation of the gas’s carrying capacity. The pressure loss mainly occurred at the inlet and the overflow outlet. When the liquid level was remained below the inlet and above the liquid outlet, the liquid level and the liquid outlet section approximately met the Bernoulli equation for a finite large flow beam. With the increase in the pressure at the gas outlet, the liquid film fell back and the separation efficiency increased gradually. These results are helpful for further spreading applications of the GLCC in industry.

scholarly journals Numerical Simulation of the Oil Droplet Size Distribution Considering Coalescence and Breakup in Aero-Engine Bearing Chamber

2020 ◽  
Vol 10 (16) ◽  
pp. 5648
Author(s):  
Fei Wang ◽  
Lin Wang ◽  
Guoding Chen ◽  
Donglei Zhu
Keyword(s):  
Size Distribution ◽  
Droplet Size ◽  
Mass Flow ◽  
Droplet Diameter ◽  
Droplet Size Distribution ◽  
Oil Droplets ◽  
Oil Droplet ◽  
Aero Engine ◽  
Oil Droplet Size ◽  
Engine Bearing

In order to improve the inadequacy of the current research on oil droplet size distribution in aero-engine bearing chamber, the influence of oil droplet size distribution with the oil droplets coalescence and breakup is analyzed by using the computational fluid dynamics-population balance model (CFD-PBM). The Euler–Euler equation and population balance equation are solved in Fluent software. The distribution of the gas phase velocity field and the volume fraction of different oil droplet diameter at different time are obtained in the bearing chamber. Then, the influence of different initial oil droplet diameter, air, and oil mass flow on oil droplet size distribution is discussed. The result of numerical analysis is compared with the experiment in the literature to verify the feasibility and validity. The main results provide the following conclusions. At the initial stage, the coalescence of oil droplets plays a dominant role. Then, the breakup of larger diameter oil droplet appears. Finally, the oil droplet size distribution tends to be stable. The coalescence and breakup of oil droplet increases with the initial diameter of oil droplet and the air mass flow increasing, and the oil droplet size distribution changes significantly. With the oil mass flow increasing, the coalescence and breakup of oil droplet has little change and the variation of oil droplet size distribution is not obvious.

scholarly journals Preparation, Characterization and Applications of Nanoemulsions: An Insight

2019 ◽  
Vol 9 (2) ◽  
pp. 520-527 ◽  
Author(s):  
Asmat Majeed ◽  
Rabiah Bashir ◽  
Saeema Farooq ◽  
Mudasir Maqbool
Keyword(s):  
Drug Delivery ◽  
Size Distribution ◽  
Droplet Size ◽  
Drug Loading ◽  
Droplet Diameter ◽  
Scale Up ◽  
Droplet Size Distribution ◽  
Biological Environment ◽  
Novel Drug

Nanoemulsions are defined as isotropic, thermodynamically stable, transparent or translucent; dispersions of oil and water stabilized by surfactant molecules (forms an interfacial film) having the droplet size of 20-500nm. Ease of preparation and scale-up, stability and increased bioavailability are features of these formulations which have attracted the attention of researchers. Its basic principle lies in its ability to spontaneously generate fine o/w microemulsion under mild agitation following dilution with aqueous phases. These conditions mimic the digestive motility in the GIT necessary to provide the agitation required for In vivo self emulsification. Unlike emulsions, self-nanoemulsified drug delivery systems (SNEDDS) generates microemulsion with a narrow droplet size distribution of less than 50 nm due to which these systems have also been addressed as nanoemulsions. Nanoemulsions (NE) are lipidic nanoformulations with droplet diameter in nanometer range have established tremendous attention as drug delivery formulations for lipophilic drugs due to their capability to increase solubility, permeation across biological membranes as well as their therapeutic efficiency of lipid soluble drugs due to predictable size-distribution, high drug loading and stability under biological environment. However there is still relatively narrow insight regarding preparation, characterization and applications of nanoemulsions. This limitation unfolds the premise for current review article. In this review, we attempt to explore varying intricacies, methods of preparation, characteristics, and drug delivery applications of nanoemulsions to spike interest of those contemplating a foray in this field. Keywords: Nanoemulsions, Novel drug delivery system, increased bioavailability.

Droplet Formation Through Centrifugal Pumps for Oil-in-Water Dispersions

SPE Journal ◽  
2012 ◽  
Vol 18 (01) ◽  
pp. 172-178 ◽  
Author(s):  
Rosanel Morales ◽  
Eduardo Pereyra ◽  
Shoubo Wang ◽  
Ovadia Shoham
Keyword(s):  
Size Distribution ◽  
Centrifugal Pump ◽  
Droplet Size ◽  
Flow Rate ◽  
Droplet Size Distribution ◽  
Droplet Formation ◽  
Centrifugal Pumps ◽  
Mixture Flow ◽  
Pump Speed ◽  
Water Cut

Summary Droplet formation in oil/water flow through a centrifugal pump has been studied, experimentally and theoretically, for the first time. Droplet-size distribution at the pump outlet has been measured for water-continuous flow as a function of pump speed, mixture-flow rate, and water cut. The measured droplet-size distribution strongly depends on the pump speed: the higher the pump speed, the smaller the droplet size. Negligible effects of mixture-flow rate, water cut, and inlet droplet-size distribution have been observed. Turbulent breakup has been identified as the main mechanism for droplet formation. A mechanistic model is developed for the prediction of droplet-size distribution in a centrifugal pump, showing a fair agreement with the acquired experimental data.

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