On the Development of Deadleg Criterion

2005 ◽  
Vol 127 (1) ◽  
pp. 124-135 ◽  
Author(s):  
M. A. Habib ◽  
H. M. Badr ◽  
S. A. M. Said ◽  
I. Hussaini ◽  
J. J. Al-Bagawi

Corrosion in deadlegs occurs as a result of water separation due to the very low flow velocity. This work aims to investigate the effect of geometry and orientation on flow field and oil/water separation in deadlegs in an attempt for the development of a deadleg criterion. The investigation is based on the solution of the mass and momentum conservation equations of an oil/water mixture together with the volume fraction equation for the secondary phase. Results are obtained for two main deadleg orientations and for different lengths of the deadleg in each orientation. The considered fluid mixture contains 90% oil and 10% water (by volume). The deadleg length to diameter ratio (L/D) ranges from 1 to 9. The results show that the size of the stagnant fluid region increases with the increase of L/D. For the case of a vertical deadleg, it is found that the region of the deadleg close to the header is characterized by circulating vortical motions for a length l≈3 D while the remaining part of the deadleg occupied by a stagnant fluid. In the case of a horizontal deadleg, the region of circulating flow extends to 3–5 D. The results also indicated that the water volumetric concentration increases with the increase of L/D and is influenced by the deadleg orientation. The streamline patterns for a number of cases were obtained from flow visualization experiments (using 200 mW Argon laser) with the objective of validating the computational model.

2012 ◽  
Vol 557-559 ◽  
pp. 2294-2298
Author(s):  
Yi Xin Pan ◽  
Hong Bing Zhang ◽  
Rong Hua Xie ◽  
Xing Bin Liu

In the oil mining process, we need to hold flow characteristic for oil- and water-sands, with low-middle volume fraction of the particles in gathered pipes, in order to design logging tool and build interpretation methods for the producing profile. We built governing equations and boundary conditions for the oil- and water-sands based on the three-D k-ε-kp model. The simulation results indicate the sand volume fraction affects the sedimentation quantity and rate obviously. Multiphase flow in the gathered pipe is compartmentalized three sections: oil-water separation section, transition section and full mixing section from entrance to exit and multiphase flow meter need to place in the full mixing section. Sediment mainly settles to the bottom of gathered pipes umbrella in the condition of low flow rate and content of sediment, which has little impact on the internal instrument, but need to clear timely. With the increase of sediment volume and reduce of flow race, the time which multiphase flow in the gathered pipe reached a steady state was nonlinear growth.


2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Yuanli Chen ◽  
Hui Fan ◽  
Xinlin Zha ◽  
Wenwen Wang ◽  
Yi Wu ◽  
...  

AbstractHigh efficiency and anti-pollution oil/water separation membrane has been widely explored and researched. There are a large number of hydroxyl groups on the surface of silica, which has good wettability and can be used for oil-water separation membranes. Hydrophilic silica nanostructures with different morphologies were synthesized by changing templates and contents of trimethylbenzene (TMB). Here, silica nanospheres with radical pores, hollow silica nanospheres and worm-like silica nanotubes were separately sprayed on the PVA-co-PE nanofiber membrane (PM). The abundance of hydroxyl groups and porous structures on PM surfaces enabled the absorption of silica nanospheres through hydrogen bonds. Compared with different silica nanostructures, it was found that the silica/PM exhibited excellent super-hydrophilicity in air and underwater “oil-hating” properties. The PM was mass-produced in our lab through melt-extrusion-phase-separation technique. Therefore, the obtained membranes not only have excellent underwater superoleophobicity but also have a low-cost production. The prepared silica/PM composites were used to separate n-hexane/water, silicone oil/water and peanut oil water mixtures via filtration. As a result, they all exhibited efficient separation of oil/water mixture through gravity-driven filtration.


Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 457
Author(s):  
Chunlei Ren ◽  
Wufeng Chen ◽  
Chusheng Chen ◽  
Louis Winnubst ◽  
Lifeng Yan

Porous Al2O3 membranes were prepared through a phase-inversion tape casting/sintering method. The alumina membranes were embedded with finger-like pores perpendicular to the membrane surface. Bare alumina membranes are naturally hydrophilic and underwater oleophobic, while fluoroalkylsilane (FAS)-grafted membranes are hydrophobic and oleophilic. The coupling of FAS molecules on alumina surfaces was confirmed by Thermogravimetric Analysis and X-ray Photoelectron Spectroscopy measurements. The hydrophobic membranes exhibited desired thermal stability and were super durable when exposed to air. Both membranes can be used for gravity-driven oil/water separation, which is highly cost-effective. The as-calculated separation efficiency (R) was above 99% for the FAS-grafted alumina membrane. Due to the excellent oil/water separation performance and good chemical stability, the porous ceramic membranes display potential for practical applications.


Open Physics ◽  
2021 ◽  
Vol 19 (1) ◽  
pp. 486-493
Author(s):  
Ting Liang ◽  
Biao Wang ◽  
Zhenzhong Fan ◽  
Qingwang Liu

Abstract A facile method for fabricating superhydrophobic and superoleophilic powder with 5A zeolite and stearic acid (SA) is reported in this study. The effect of different contents of SA on contact angle (CA) was investigated. The maximum water CA was 156.2°, corresponding to the optimum SA content of 1.5 wt%. The effects of SA and the mechanism of modified 5A zeolite powder by SA were analyzed by sedimentation analysis experiment, FTIR analysis, particle size analysis, and SEM characterization. The SA-modified 5A zeolite was used as an oil sorbent to separate oil–water mixture with potential use in floating oil. The separation efficiency was above 98%.


MRS Advances ◽  
2017 ◽  
Vol 2 (31-32) ◽  
pp. 1699-1706
Author(s):  
Hussain Al-Qahtani ◽  
Michael S. H. Boutilier ◽  
Rahul Ramakrishnan ◽  
Rohit Karnik

ABSTRACTThis article presents a laboratory module developed for undergraduate micro/nano engineering laboratory courses in the mechanical engineering departments at the Massachusetts Institute of Technology and King Fahd University of Petroleum and Minerals. In this laboratory, students fabricate superoleophobic membranes by spray-coating of titania nanoparticles on steel meshes, characterize the surfaces and ability of the membrane to retain oil, and then use these membranes to separate an oil-water mixture. The laboratory module covers nanomaterials, nanomanufacturing, materials characterization, and understanding of the concepts of surface tension and hydrostatics, with oil-water separation as an application. The laboratory experiments are easy to set up based on commercially available tools and materials, which will facilitate implementation of this module in other educational institutions. The significance of oil-water separation in the petroleum industry and integration of concepts from fluid mechanics in the laboratory module will help to illustrate the relevance of nanotechnology to mechanical and materials engineering and its potential to address some of the future societal needs.


2020 ◽  
Vol 8 ◽  
Author(s):  
Usama Zulfiqar ◽  
Andrew G. Thomas ◽  
Allan Matthews ◽  
David J. Lewis

Oil/water mixtures are a potentially major source of environmental pollution if efficient separation technology is not employed during processing. A large volume of oil/water mixtures is produced via many manufacturing operations in food, petrochemical, mining, and metal industries and can be exposed to water sources on a regular basis. To date, several techniques are used in practice to deal with industrial oil/water mixtures and oil spills such as in situ burning of oil, bioremediation, and solidifiers, which change the physical shape of oil as a result of chemical interaction. Physical separation of oil/water mixtures is in industrial practice; however, the existing technologies to do so often require either dissipation of large amounts of energy (such as in cyclones and hydrocyclones) or large residence times or inventories of fluids (such as in decanters). Recently, materials with selective wettability have gained attention for application in separation of oil/water mixtures and surfactant stabilized emulsions. For example, a superhydrophobic material is selectively wettable toward oil while having a poor affinity for the aqueous phase; therefore, a superhydrophobic porous material can easily adsorb the oil while completely rejecting the water from an oil/water mixture, thus physically separating the two components. The ease of separation, low cost, and low-energy requirements are some of the other advantages offered by these materials over existing practices of oil/water separation. The present review aims to focus on the surface engineering aspects to achieve selectively wettability in materials and its their relationship with the separation of oil/water mixtures with particular focus on emulsions, on factors contributing to their stability, and on how wettability can be helpful in their separation. Finally, the challenges in application of superwettable materials will be highlighted, and potential solutions to improve the application of these materials will be put forward.


2020 ◽  
Vol 142 (11) ◽  
Author(s):  
Weiwei E. ◽  
Kevin Pope ◽  
Xili Duan

Abstract In this paper, a new correlation is developed to predict liquid/liquid separation dynamics with a focus on a water/oil mixture. The correlation employs a force balance on the droplets to predict the rising velocity of the oil phase. The effect of droplet coalescence on the droplet's rising velocity is investigated, and the new correlation predicts the coalescence rate based on the oil/water volume fraction, as well as the initial droplet diameter. To develop the correlation for droplet coalescence, a series of new numerical simulations of a batch oil/water separation process were conducted. An equivalent experiment was conducted, the results of which agree well with the numerical predictions (relative error of 13.39%). The new correlation can predict the rate of separation with a relative error of 6.35% compared to numerical predictions.


Author(s):  
Ang Li ◽  
Jianfeng Bai ◽  
Yun Shen ◽  
Hang Jin ◽  
Wei Wang ◽  
...  

The three-phase separator has a wide range of applications in oil production industry. For the purpose of studying the effect of heating temperature, demulsifiers and water content on the separation of oil-water mixture in the three-phase separator, eight kinds of oil samples were taken from different oil transfer stations in Changqing Oilfield and the mixtures were prepared by stirring method. To simulate the two-stage dehydration process, the first stage dehydration experiments without any heating were performed on mixtures at the dose of 100ppm demulsifer at 20°C, and the water cut of these mixtures is the same as that of the gathering pipeline in each oil transfer station. The water cut of the upper crude oil was measured after 40 minutes, and the values of them ranged from 0.5 vol% to 65.2 vol%. No visual stratification was observed for the sample most difficult to separate, so it was selected to conduct the second stage dewatering process. Three bottles of the same mixture were prepared and heated to 30°C, 40°C and 50°C, respectively. The results showed that all of them stratified in 10 minutes, and the water-cut values of the upper oil layer were 1.4 vol%, 0.5 vol% and 0.3 vol%, respectively, compared to 65.2 vol% at 20°C. When the concentration of demulsifier was changed to 200ppm and 300ppm, the results exhibited almost no differences. So it is deduced that the further improvement of heating temperature and demulsifier dose have limited enhancement on oil-water separation. At Last, 35 vol%, 50 vol%, 70 vol% and 85 vol% water cut mixtures of the special oil sample were made to experiment as previously. In consequence, the 35 vol% water-cut emulsions presented a relatively slow rate of oil-water stratification at low heating temperature, and the oil content of the lower separated water was improved by the addition of demulsifier dosage above 100ppm when the water cut was 90 vol%. It is indicated that high heating temperature is necessarry for low water-cut mixtures oil-water separation and can be appropriately reduced to save energy consumption as the water cut continues to rise. The demulsifier dosage is also neccessary be controlled in high water cut period. These experimental data provide the basis for the further optimization operation of the three-phase separator.


2019 ◽  
Vol 10 (37) ◽  
pp. 5142-5150 ◽  
Author(s):  
Ji Ae Chae ◽  
Yuree Oh ◽  
Hea Ji Kim ◽  
Go Bong Choi ◽  
Kyoung Min Lee ◽  
...  

A bottom-up design enables the preparation of a mesoporous, compressible, polymer monolith that shows rapid separation of oil–water mixture.


Polymers ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 1629
Author(s):  
Xuecheng Yu ◽  
Ying Xiong ◽  
Zhen Li ◽  
Hongding Tang

Three series of silicone modified polyurethane acrylate (SPUA) prepolymers were prepared from dicyclohexylmethane-4, 4′-diisocyanate (HMDI), PPG1000, triethylene glycol (TEG), 2-hydroxyethyl acrylate (HEA), and multi-hydroxyalkyl silicone (MI-III) with tris(trimethylsiloxy)silyl propyl side groups. Their structures were confirmed by 1H NMR, 13C NMR, and Fourier transformed infrared (FTIR) analysis, and SPUA films were obtained by UV curing. The properties of films were investigated by attenuated total reflection (ATR)-FTIR, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), water contact angle (WCA), thermogravimetric analysis (TGA), differential scanning calorimeter (DSC), water and hexane resistance, and tensile testing. The results showed that the structures and dosages of MI-III could influence the polymerization properties, surface properties, water and n-hexane resistance, and thermal and tensile properties of SPUA. For instance, the surface aggregation of tris(trimethylsiloxy)silyl propyl groups (even ~2.5 wt%) could endow SPUA films with less microphase separation, good hydrophobicity, lipophilicity, thermal stability, and mechanical properties. Interestingly, obvious regular winkles appeared on the surfaces of SPUAIII films, which are characterized by relatively high WCA values. However, relatively smooth were observed on the surfaces of SPUAIII films, which also exhibit lower water absorption ratio values. Furthermore, the ordinary cotton textiles would be transformed into hydrophobic and oleophilic textiles after treating with SPUA simply, and they were used in the oil/water separation study. Among them, consistent with water and hexane resistance analysis of SPUA films, SPUAII treated cotton textiles are characterized by relatively small liquid absorption capacity (LAC) values. Thus, phenyl groups and side-chain tris(trimethylsiloxy)silyl propyl groups are helpful to improve the hydrophobicity and lipophilicity of SPUA films. SPUAII-5 (even with 5 wt% MII) treated cotton textiles could efficiently separate the oil/water mixture, such as n-hexane, cyclohexane, or methylbenzene with water. Thus, this material has great potential in the application of hydrophobic treatment, oil/water separation, and industrial sewage emissions, among others.


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