The Coarse Particle Influence on the Strength of Wax Deposition

2020 ◽  
Author(s):  
Xun Zhang ◽  
Qiyu Huang ◽  
Yu Zhang ◽  
Yaping Li ◽  
Xin Liu
Keyword(s):  
Yield Stress ◽  
Colloidal Particles ◽  
Critical Mass ◽  
Solid Particles ◽  
Coarse Particle ◽  
Silica Sand ◽  
Coarse Particles ◽  
Wax Deposition ◽  
Wax Deposits ◽  
The Impact

Abstract Wax deposition has always been an essential issue for flow assurance, especially in subsea pipelines. The coarse particles, which are usually measured in millimeters, will be carried out by oil flow during the deep-water oil fields production. However, due to insufficient understanding of the structure of wax deposits and the complexity of sandy crude oil deposition, the interaction between coarse particles and wax deposits in the pipeline have rarely been investigated. In this paper, the effect of coarse particles on the yield stress of wax deposits has been studied. The sample was mixed at reversible structure temperature so that the impact of shear history could be eliminated, and the rapid particle settlement at high temperature could be avoided. Experimental results have found that there is a critical fraction in coarse particle influences, below which a small number of coarse particles added will lead to a slight increase in bulk yield stress. On the contrary, a dramatic decrease in yield stress when exceeding the critical mass fraction and increasingly marked enhancement of yield stress as the fraction increases. This phenomenon has been explicated microscopically by the structural interaction between coarse particles and wax deposits. The interlock between wax crystals is the major contribution of the structure as the less particle fraction contains. Even though the silica sand is a typical non-colloidal particle, the asphaltene and resin could be absorbed on the surface of particles and forming a cluster of colloidal particles. As the fraction of particles slightly increased, the slip between colloidal particles and wax crystal interlock accelerates structural failure. Nevertheless, more particles involved the overall yield stress may depend on the friction and the adhesive force between solid particles. The subtle changes induced by coarse particles would have a harder deposit, which can hinder pig passing and affect pipeline pigging operations.

Impact of Molecular Chain Structure of Suspension Phase on Giant Electrorheological Performance

2022 ◽  
Author(s):  
Hanqi Xu ◽  
Jinbo Wu ◽  
Yaying Hong ◽  
Weijia Wen
Keyword(s):  
Yield Stress ◽  
Chain Length ◽  
Colloidal Stability ◽  
Chain Structure ◽  
Solid Particles ◽  
High Yield ◽  
Suspension Stability ◽  
Chain Lengths ◽  
The Impact ◽  
Oil Particles

Abstract We demonstrate the impact of diester structure, in particular the alkyl chain length and branching structure, on the giant electrorheological (GER) effect and suspension stability. The existence of oil-particles interaction is of critical importance to induce the GER effect. To quantify GER performance and colloidal stability, we examine the yield stress, current density, field-off viscosity and sedimentation ratio with respect to the variation of chain length and branching structure. The oil-particles interaction is quantitatively analyzed by investigating the cluster size of particles in different diesters by a multiple light scattering analyzer, along with the wettability of different chain lengths of diesters and solid particles by the Washburn method. Our results indicate that long chain lengths favor the formation of particle agglomerates, thereby enhancing the GER effect (such as high yield stress). The attachment of branches on diester causes the formation of electronic correlation between branches and main chain, depending on the position of branches located, and hence results in superior GER performance and favorable suspension stability. An optimal GER fluid constituted by bis(2-ethylhexyl) sebacate is acquired with the achieved yield stress of 113 kPa at electric field strength of 4 kV/ mm and the prominent integrated GER properties.

Assessment of the Impact of Wax Deposition in a Pre-Salt Project

2021 ◽  
Author(s):  
Nathalie Carvalho Pinheiro ◽  
Sergio Paulo Gomes Pinho
Keyword(s):  
Diffusion Coefficient ◽  
Wax Deposition ◽  
Full Field ◽  
Deposition Model ◽  
High Production ◽  
The One ◽  
Wax Deposits ◽  
Transient Models ◽  
The Impact ◽  
Production Losses

Abstract Despite pre-salt fields in Brazil usually having high production per well, one of the areas presents a reservoir with low permoporosity, which results in small flowrates with fluid temperatures during production below the one that is critical for wax deposition. The operations commonly used to remove the wax deposits are diesel soaking and pigging, which brings production losses and OPEX increase. Thus, the economic analysis should consider these events reducing the operational efficiency of production. To evaluate the production drop due to wax deposition, it was necessary to perform a loop test to determine the wax growth throughout time. With a multiphase simulator, it is possible to choose the deposition model and the diffusion coefficient that best fits the analyzed fluid. However, one of the limitations of this first analysis is the lack of data to determine the effect of the shear stripping, as the test is performed under a laminar flow. As this term plays an important role in wax growth, it was necessary to add to the simulation model the shear coefficient fitted from another pre-salt field. With this information, it will be possible to make a more reliable evaluation of the impact of wax deposition, increasing the confidence in the production curve, OPEX and NPV of the full field project. This paper shows the methodology that has been applied to evaluate the impact of wax deposition in pre-salt fields. It presents the deposition model, and its coefficients used to fit the multiphase transient models to a pre-salt field.

Particle Stability in Dilute Fermented Dairy Drinks: Formation of Fluid Gel and Impact on Rheological Properties

2010 ◽  
Vol 16 (6) ◽  
pp. 543-551 ◽  
Author(s):  
H. Kiani ◽  
M.E. Mousavi ◽  
Z.E. Mousavi
Keyword(s):  
Rheological Properties ◽  
Yield Stress ◽  
Colloidal Particles ◽  
Solid Particles ◽  
Particle Stability ◽  
Wide Availability ◽  
Application Potential ◽  
Transient Interactions ◽  
The Stability ◽  
Fermented Dairy

Fluid gels are known to be very shear-thinning materials with yield stress. In this study, the rheological properties of gellan and gellan—pectin fluid gels in fermented dairy drinks were evaluated using viscometric measurements. Both gellan- and gellan—pectin-containing solutions showed the rheological properties of fluid gels resulting in stabilization of particles; but no evidence of a fluid gel was observed for those with pectin alone and those with no hydrocolloid content. Unlike pectin, gellan gum was capable of creating significant values of yield stress and accordingly stabilized colloidal particles and extrinsic added solid particles in the fermented dairy drink. However, pectin improved the stability in combination with gellan. The origin of fluid gel formation was assumed to be both permanent interactions occurring between gellan and proteins, forming hairy particle gels and transient interactions between the particle gels. The significance of yield stress values for particle stability was demonstrated and two methods, including a noteworthy infinite apparent viscosity method and a conventional Bingham approach, were employed to calculate the values of yield stress. Both the methods showed a good application potential due to their simplicity, reasonable results and also wide availability of the instrument applied.

Australian Biotechnology: A 10-Year Study of Investor Performance

2021 ◽  
Vol 26 (4) ◽  
Author(s):  
Peter L. Molloy ◽  
Lester W. Johnson ◽  
Michael Gilding
Keyword(s):  
Drug Development ◽  
Global Financial Crisis ◽  
Critical Mass ◽  
Share Price ◽  
Annual Growth Rate ◽  
Compound Annual Growth Rate ◽  
Listed Firms ◽  
Investor Returns ◽  
The Global Financial Crisis ◽  
The Impact

A recent study assessed the investor performance of the Australian drug development biotech (DDB) sector over a 15-year period from 2003 to 2018. The current study builds on that research and extends the analysis to 2020, using a 10-year period starting 2010, to exclude the impact of the global financial crisis in 2008/09. Based on a value-weighted portfolio of all 41 DDB firms, the overall sector delivered a negative annualized return of -4.1%. Individual firm performance was also assessed using the compound annual growth rate (CAGR) in share price over the period as a measure of investor outcomes. On this basis 68% of firms produced negative CAGRs over the period, and of the 32% of firms that produced positive CAGRs, six firms produced CAGRs greater than 20% per annum and in three cases of recently-listed firms, the CAGR’s were greater than 50%. Overall however, the sector overall delivered very poor investor returns and despite a relatively large number of listed biotech firms, Australian biotechnology continues to be small and weak in terms of its contribution to global biotechnology industrialization. As such it lacks the critical mass to grow a robust bioeconomy based on drug development, which remains the standard-bearer of biotechnology industrialization.

On the Impact Behavior of a Material With a Yield Point

1949 ◽  
Vol 16 (1) ◽  
pp. 39-52
Author(s):  
Merit P. White
Keyword(s):  
Yield Stress ◽  
Yield Point ◽  
Impact Behavior ◽  
Longitudinal Impact ◽  
Stress Strain ◽  
California Institute Of Technology ◽  
Static Yield ◽  
Institute Of Technology ◽  
Probable Nature ◽  
The Impact

Abstract An analysis of longitudinal impact tests that were made by Drs. D. S. Clark and P. E. Duwez at the California Institute of Technology on an iron and a steel with definite yield points is described. From this analysis is deduced the probable nature of the dynamic stress-strain relations for such materials. These appear to differ greatly from the static stress-strain relations, unlike the case for materials without yield points. As pointed out by Duwez and Clark, the upper yield stress for undeformed material is several times as great under impact as the static yield stress. The present analysis indicates that under impact, the material with a definite yield point is made harder at a given deformation, and ruptures at a higher (engineering) stress and smaller strain than when loaded statically. The critical impact velocity, defined as that at which nearly instantaneous failure occurs in tension, is discussed, and the factors upon which it depends are given.

Erosion Mechanism and Sensitivity Parameter Analysis of Natural Gas Curved Pipeline

2019 ◽  
Vol 141 (3) ◽  
Author(s):  
Jie Zhang ◽  
Hao Yi ◽  
Zhuo Huang ◽  
Jiadai Du
Keyword(s):  
Natural Gas ◽  
Wear Rate ◽  
Shape Factor ◽  
Great Influence ◽  
Solid Particles ◽  
Parameter Analysis ◽  
Particle Collision ◽  
Erosion Wear ◽  
Gas Wells ◽  
The Impact

With the deepening of natural gas exploitation, the problem of sand production in gas wells is becoming more and more serious, especially in high-yield gas wells. The solid particles in natural gas are very likely to cause erosion and wear of downstream pipelines and throttling manifolds, which makes the pipeline ineffective. Once the pipeline is damaged, the natural gas leaks, which may cause serious catastrophic accidents. In this paper, the impact of sand particles on the pipeline wall is predicted by the analysis of the research on bent and continuous pipeline combined with particle collision model. The parameters of different particles (particle shape factor, particle velocity, and particle diameter), different bent parameters (angle, diameter, and curvature-to-diameter ratio), and the influence of different continuous pipeline parameters (assembly spacing and angle) are explored on the erosion and wear mechanism of curved pipeline. The results show that the shape of the particles has a great influence on the wear of the curved pipeline. As the shape factor of the particles decreases, the wear tends to decrease. The bent area is subject to erosion changes as the particle parameters and piping parameters. The increase in pipeline diameter is beneficial to reduce the maximum and the average erosion wear rate. When the bent angle of the pipeline is less than 90 deg, the maximum erosion wear rate is basically the same. But when it is greater than 90 deg, it decreases with the increase in the bent angle. When the assembly angle of double curved pipeline is between 0 deg and 60 deg, the elbow is subject to severe erosion wear. At the same time, increasing the assembly spacing is beneficial to reduce the erosion wear rate. The research can provide a theoretical support for subsequent engineering applications.

On the Attainability of Fusion Temperatures under High Densities by Impact Shock Waves of Small Solid Particles Accelerated to Hypervelocities

1964 ◽  
Vol 19 (2) ◽  
pp. 231-239 ◽  
Author(s):  
F. Winterberg
Keyword(s):  
Shock Waves ◽  
Heavy Particle ◽  
Target Material ◽  
Particle Beam ◽  
Solid Particles ◽  
Particle Accelerators ◽  
Bremsstrahlung Radiation ◽  
The Impact ◽  
Controllable Size ◽  
Impact Shock

In this paper it is shown that temperatures up to 108°K and under densities of the order 1 g/cm3 are attainable in liquid tritium-deuterium by the impact shock waves of small solid particles accelerated up to velocities of some 107 cm/s in heavy particle accelerators.The high temperatures occur in a focussed particle beam. It is shown that under feasible conditions, the particle beam will generate in the target material a shock wave of the required strength. The particles are charged electrically up to the limit of mechanical breakup and then are accelerated in linear particle accelerators to the required velocities.In order to cut down losses by Bremsstrahlung radiation, the particles must consist of low Z-value material. The most promissing substances in this regard are lithium and beryllium. The "guillotine factor” is of significance at high densities and reduces the Bremsstrahlung losses by a factor of about 1/3.The attainable temperatures are high enough to reach the lowest ignition temperatures for thermonuclear reactions.Apart from the interesting prospect of high temperature, high density experiments, the possibility cannot be excluded to ignite by this method a small fusion explosion of controllable size.

scholarly journals The effect of national cultural differences of board members on integrated reporting

2018 ◽  
Vol 14 (1) ◽  
pp. 7-21 ◽  
Author(s):  
Simona Alfiero ◽  
Massimo Cane ◽  
Ruggiero Doronzo ◽  
Alfredo Esposito
Keyword(s):  
Cultural Differences ◽  
Critical Mass ◽  
Cultural Dimensions ◽  
Board Members ◽  
Cultural Dimension ◽  
Integrated Reporting ◽  
Independent Variables ◽  
The Impact ◽  
The Relationship ◽  
Positive Effect

This research, based on stakeholder theory and the national cultural dimensions, aims to test the influence of foreigners on board and its size on Integrated Reporting (IR) practices. The analysis is based on a sample of 1,058 European companies from 18 different countries, who adopted or not the IR for the year 2015, and it relies on a Logit. The dependent variable is a dummy (presenting or not the IR) and the independent variables are represented by the board characteristics (foreigners and size). The impact of the critical mass on the presence of foreigners and the cultural dimension on the basis of directors’ nationality was tested relying on the masculinity/femininity dimension of Hofstede. Besides, the directors’ country of origin was considered, namely if they belong to the major European countries presenting a wider IR diffusion. The relationship between foreigners on board and IR is found to be negative. This means that companies with at least one foreigner are less inclined to adopt IR. The results show that the boards with more of three foreign administrators have a major propensity to adopt the IR. The membership of the directors in countries with a feminist culture also has a positive effect.

scholarly journals An Attempt to Reduce the Emission of Spark-Ignition Engine with Mixtures of Bioethanol and Gasoline as Substitute Fuels

2019 ◽  
Vol 26 (3) ◽  
pp. 31-38
Author(s):  
Wojciech Gis ◽  
Maciej Gis ◽  
Piotr Wiśniowski ◽  
Mateusz Bednarski
Keyword(s):  
Carbon Dioxide ◽  
Fuel Consumption ◽  
Carbon Dioxide Emissions ◽  
Alternative Fuels ◽  
Negative Impact ◽  
Spark Ignition ◽  
Solid Particles ◽  
Spark Ignition Engine ◽  
Maximum Power ◽  
The Impact

Abstract Limiting emissions of harmful substances is a key task for vehicle manufacturers. Excessive emissions have a negative impact not only on the environment, but also on human life. A significant problem is the emission of nitrogen oxides as well as solid particles, in particular those up to a diameter of 2.5 microns. Carbon dioxide emissions are also a problem. Therefore, work is underway on the use of alternative fuels to power the vehicle engines. The importance of alternative fuels applies to spark ignition engines. The authors of the article have done simulation tests of the Renault K4M 1.6 16v traction engine for emissions for fuels with a volumetric concentration of bioethanol from 10 to 85 percent. The analysis was carried out for mixtures as substitute fuels – without doing any structural changes in the engine's crankshafts. Emission of carbon monoxide, carbon dioxide, hydrocarbons, oxygen at full throttle for selected rotational speeds as well as selected engine performance parameters such as maximum power, torque, hourly and unit fuel consumption were determined. On the basis of the simulation tests performed, the reasonableness of using the tested alternative fuels was determined on the example of the drive unit without affecting its constructions, in terms of e.g. issue. Maximum power, torque, and fuel consumption have also been examined and compared. Thus, the impact of alternative fuels will be determined not only in terms of emissions, but also in terms of impact on the parameters of the power unit.

A mixed contact model for an immersed collision between two solid surfaces

2008 ◽  
Vol 366 (1873) ◽  
pp. 2205-2218 ◽  
Author(s):  
Fu-Ling Yang ◽  
Melany L Hunt
Keyword(s):  
Surface Deformation ◽  
Elastohydrodynamic Lubrication ◽  
Solid Particles ◽  
Solid Surfaces ◽  
Additional Energy ◽  
Collision Model ◽  
Dry Granular Flow ◽  
Wide Range ◽  
The Impact ◽  
Surrounding Liquid

Experimental evidence shows that the presence of an ambient liquid can greatly modify the collision process between two solid surfaces. Interactions between the solid surfaces and the surrounding liquid result in energy dissipation at the particle level, which leads to solid–liquid mixture rheology deviating from dry granular flow behaviour. The present work investigates how the surrounding liquid modifies the impact and rebound of solid spheres. Existing collision models use elastohydrodynamic lubrication (EHL) theory to address the surface deformation under the developing lubrication pressure, thereby coupling the motion of the liquid and solid. With EHL theory, idealized smooth particles are made to rebound from a lubrication film. Modified EHL models, however, allow particles to rebound from mutual contacts of surface asperities, assuming negligible liquid effects. In this work, a new contact mechanism, ‘mixed contact’, is formulated, which considers the interplay between the asperities and the interstitial liquid as part of a hybrid rebound scheme. A recovery factor is further proposed to characterize the additional energy loss due to asperity–liquid interactions. The resulting collision model is evaluated through comparisons with experimental data, exhibiting a better performance than the existing models. In addition to the three non-dimensional numbers that result from the EHL analysis—the wet coefficient of restitution, the particle Stokes number and the elasticity parameter—a fourth parameter is introduced to correlate particle impact momentum to the EHL deformation impulse. This generalized collision model covers a wide range of impact conditions and could be employed in numerical codes to simulate the bulk motion of solid particles with non-negligible liquid effects.

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