Effects of the Types and Addition Amounts of Sludge on the True Rheological Properties of Petroleum Coke Slurry Flowing in Pipelines

2015 ◽  
Vol 13 (3) ◽  
pp. 311-322 ◽  
Author(s):  
Meng Liu ◽  
Yufeng Duan ◽  
Xiuyuan Ma
Keyword(s):  
Shear Rate ◽  
Rheological Properties ◽  
Petroleum Coke ◽  
Slip Velocity ◽  
Wall Slip ◽  
Paper Mill ◽  
Shear Thinning ◽  
Tikhonov Regularization Method ◽  
Plastic Fluid ◽  
Dilatant Fluid

AbstractEffects of the types and addition amounts of sludge on the true rheological properties of petroleum coke water/sludge slurry (PCWS/PCSS) flowing in pipelines were investigated using the Tikhonov regularization method. Results show that PCWS of 59.8 wt% changes from pseudo-plastic fluid to dilatant fluid as the shear rate increases. However, PCWS of 63.4 wt% is a very complex fluid: shear thinning at low shear rate, followed by shear thickening over a critical shear rate, and a subsequent shear thinning at high shear rate. Rheological properties of PCWS have a significant change after the sludge was added. PCSS changes from dilatant fluid to pseudo-plastic fluid when the addition amounts of sewage sludge ascend to 10 wt%. Petroleum coke particles are trapped by the stable “network” structures, which are formed by flocculent sludge particles. The wall slip velocity of PCSS is higher than that of PCWS with the sludge amount increases, which is beneficial for pipe transportation. In addition, the wall slip velocity of PCSS containing sewage or petrochemical sludge increases with the wall shear rate increases, but the slip velocity of PCSS containing paper mill sludge first increases and then decreases.

scholarly journals Quantification of shear viscosity and wall slip velocity of highly concentrated suspensions with non-Newtonian matrices in pressure driven flows

2021 ◽  
Author(s):  
Patrick Wilms ◽  
Jan Wieringa ◽  
Theo Blijdenstein ◽  
Kees van Malssen ◽  
Reinhard Kohlus
Keyword(s):  
Shear Stress ◽  
Liquid Phase ◽  
Shear Rate ◽  
Shear Viscosity ◽  
Slip Velocity ◽  
Volume Fraction ◽  
Solid Volume Fraction ◽  
Wall Slip ◽  
Flow Index ◽  
Concentrated Suspensions

AbstractThe rheological characterization of concentrated suspensions is complicated by the heterogeneous nature of their flow. In this contribution, the shear viscosity and wall slip velocity are quantified for highly concentrated suspensions (solid volume fractions of 0.55–0.60, D4,3 ~ 5 µm). The shear viscosity was determined using a high-pressure capillary rheometer equipped with a 3D-printed die that has a grooved surface of the internal flow channel. The wall slip velocity was then calculated from the difference between the apparent shear rates through a rough and smooth die, at identical wall shear stress. The influence of liquid phase rheology on the wall slip velocity was investigated by using different thickeners, resulting in different degrees of shear rate dependency, i.e. the flow indices varied between 0.20 and 1.00. The wall slip velocity scaled with the flow index of the liquid phase at a solid volume fraction of 0.60 and showed increasingly large deviations with decreasing solid volume fraction. It is hypothesized that these deviations are related to shear-induced migration of solids and macromolecules due to the large shear stress and shear rate gradients.

Development of Viscosified Acid-Surfactant Solutions for Oilfield Applications: Rheological Properties

2020 ◽  
Vol 143 (2) ◽  
Author(s):  
Lionel Talley Fogang ◽  
Muhammad Shahzad Kamal ◽  
Mohamed Mahmoud
Keyword(s):  
Shear Rate ◽  
Acid Solution ◽  
Rheological Properties ◽  
Calcium Chloride ◽  
Elastic Properties ◽  
Salt Concentration ◽  
Shear Thinning ◽  
Rate Range ◽  
Shear Rates ◽  
Surfactant Solutions

Abstract Viscosified acids are desired in several oilfield applications such as in acid diversion and acid fracturing operations. The study aimed to delineate the rheological properties of a novel amine type surfactant and viscosified acid-surfactant solutions. The steady shear and dynamic rheological properties were evaluated by varying the surfactant, acid, and salt concentration. Such a study is required to gauge the suitability of the viscosifying agent in acid stimulation jobs. The surfactant solutions without acid showed shear-thinning behavior, whereas those with acid showed a Newtonian plateau over a wide shear rate range before undergoing shear thinning. This means that over a wide shear rate range, the acid-surfactant solutions become independent of applied shear. At low shear rates, the viscosity of the surfactant was higher compared with the surfactant-acid solution. However, at high shear rates, the viscosity of the surfactant was lower compared with the viscosity of the surfactant-acid solution. There was an optimal salt concentration that improved the viscosity and elasticity of the acid-surfactant solutions. Thus, the rheology of the surfactant solution can be improved by adding both acid and salt. The elastic properties of acid-surfactant solutions were also better compared with the elastic properties of pure surfactant. The addition of acid improved the elastic properties of the surfactant solutions. Constant viscosity over a range of shear rate is a suitable application for acid fracturing operations in which the acid leak-off will be minimal due to the high viscosity. Also, brines in most of the carbonate formation consist of high loading of calcium chloride which was found to have a positive effect on the viscosity. Increasing the calcium chloride leads to an increase in viscosity, and then subsequently decreases the viscosity. This shows that the acid and salt concentration plays a role in modifying the rheological properties of the surfactant solutions.

scholarly journals Shear thinning and thickening of cemented paste backfill

2019 ◽  
Vol 29 (1) ◽  
pp. 80-93 ◽  
Author(s):  
Liuhua Yang ◽  
Hongjiang Wang ◽  
Aixiang Wu ◽  
Hong Li ◽  
Arlin Bruno Tchamba ◽  
...  
Keyword(s):  
Shear Rate ◽  
Rheological Properties ◽  
Yield Stress ◽  
Shear Thinning ◽  
High Shear ◽  
Cemented Paste Backfill ◽  
Concentrated Suspension ◽  
History Effects ◽  
Paste Backfill ◽  
Shear History

Abstract Cemented paste backfill (CPB) is considered to be a concentrated suspension in which tailings are bonded together by the hydraulic binder and water, and it has a high solid volume concentration (≥50 vol.%). Although the shear thinning and thickening of CPB has been extensively reported in literature, the shear history effects have been ignored in previous studies. In this paper, by using rheometer and Focused Beam Reflectance Measurement, the relationship between the rheological properties and microstructure of the paste under different shear histories was studied. The results have shown that at a low shear rate, CPB revealed shear thinning, low yield stress and low index parameters; while exhibited shear thickening, high yield stress and high consistency index when at high shear rates of shear history. This agreed with the general trends shown in the FBRM analysis. It was proposed that the action of shear is beneficial to particle dispersion, whereas a high shear rate history tends to promote the aggregation of particles. It was revealed that both shear thinning and thickening of paste are related to the situation of particles (flocculation, dispersion and aggregation), and shear history effects play an important role in rheological properties of CPB.

Flow Properties and Melt Distortion in Molten Rubber Compounds under Capillary Extrusion

2013 ◽  
Vol 747 ◽  
pp. 627-630
Author(s):  
Watcharapong Chookaew ◽  
Yanichsa Sukniyom ◽  
Somjate Patcharaphun ◽  
Narongrit Sombatsompop
Keyword(s):  
Shear Rate ◽  
Rheological Properties ◽  
Apparent Viscosity ◽  
Wall Slip ◽  
Skin Layer ◽  
Rubber Compound ◽  
Melt Fracture ◽  
Extrudate Swell ◽  
Rubber Compounds ◽  
Capillary Extrusion

The influences of shear rate and vulcanizing system on the rheological properties and melt fracture of natural rubber compounds were investigated by using a rate-controlled capillary rheometer. The rheological properties of rubber compounds were characterized with respect to the apparent viscosity and extrudate swell. The measured results indicated that the apparent viscosity tended to decrease with increasing shear rate. This was due to the pseudoplastic behavior of molten rubber compound. It was evident that rubber compound using EV system showed the lowest apparent viscosity as compared to those obtained by CV and NS systems, respectively. This was due to the occurrences of premature crosslink at the skin layer and the wall slip of rubber compound during the flow in capillary die. Furthermore, the onset of smooth surface was also observed which depending on the types of crosslink at the skin layer.

Rheological Characteristics of Surfactant-Based Fluids: A Comprehensive Study

2018 ◽  
Author(s):  
Ahmed H. Kamel
Keyword(s):  
Shear Rate ◽  
Rheological Properties ◽  
Rheological Behavior ◽  
Surfactant Concentration ◽  
Flow Direction ◽  
Shear Thinning ◽  
Molecular Structures ◽  
Wide Range ◽  
Unique Nature ◽  
Viscoelastic Surfactant

Surfactant-based fluids, SB fluids exhibit complex rheological behavior due to substantial structural change caused by the molecules self-assembled colloidal aggregation. Various factors affect their rheological properties. Among these factors, surfactant concentration, shear rate, temperature, and salinity are investigated. One of the most popular surfactants, Aromox® APA-T viscoelastic surfactant (VES) is examined. The study focuses on four different concentrations (1.5%, 2%, 3%, and 4%) over a shear rate ranging from 0.0526 sec−1 to 1944 sec−1 using Bohlin rheometer. For salinity effects, two brine solutions are used; 2 and 4% KCl while for temperature effects, a wide range from ambient temperature of 72°F up to 200°F is covered. The results show that SB fluids exhibit a complex rheological behavior due to its unique nature and the various structures form in the solution. In general, SB fluids at all concentrations exhibit a non-Newtonian pseudo-plastic shear thinning behavior. As the surfactant concentration and/or shear increases, a stronger shear thinning behavior can be seen. Increasing solution salinity promotes formation of rod-like micelles and increases its flexibility. Salinity affects micelles’ growth and their rheological behavior is very sensitive to the nature and structure of the added salt. Different molecular structures are formed; spherical micelles occur first and then increased shear rate and/or salinity promotes the formation of rod-like micelles. Later, rod-like micelles are aligned in the flow direction and form a large super ordered structure of micellar bundles or aggregates called shear induced structure (SIS). Different structures implies different rheological properties. Likewise, rheology improves with increasing temperature up to 100°F. Further increase in temperature reverses the effects and viscosity decreases. However, the effects of temperature and salinity diminish at higher shear rates. Furthermore, a rheology master curve is developed to further understand the rheological behavior of SB fluids and correlate rheological properties to its microscopic structure.

Laponite Nanoparticle as a High Performance Rheological Modifier in Water-Based Drilling Fluids

2018 ◽  
Vol 917 ◽  
pp. 134-139
Author(s):  
Fan Liu ◽  
Guang Cheng Jiang ◽  
Kai Wang ◽  
Jin Xi Wang
Keyword(s):  
Shear Rate ◽  
Rheological Properties ◽  
Yield Point ◽  
High Performance ◽  
Shear Thinning ◽  
Drilling Fluids ◽  
Star Network ◽  
Water Based ◽  
Rate Test ◽  
Rheological Modifier

In this paper, we demonstrated an artificial nanoparticles, Laponite, as a high performance rheological modifier in water-based drilling fluids. We made a comparison between Laponite nanoparticle and bentonite as rheological modifier in polyanionic cellulose (PAC) solution and weitghted water-based drilling fluids. In viscosity-shear rate test, both Laponite and bentonite could translate 0.5 wt.% PAC solution from Newton fluids to yield-pseudoplastic fluid. However, 1 wt.% Laponite was better in improving the shear-thinning behavior compared with 4 wt.% bentonite. In the stress-shear rate test, the results were fit with Bingham model with a high R2, and 1 wt.% Laponite/0.5 wt.% PAC suspension had a yield point of 5.19 Pa, which was higher than that of 4 wt.% bentonite/0.5 wt.% PAC suspension (3.13 Pa). Similarly, 1 wt.% Laponite/0.5 wt.% PAC suspension maintained a G’ of 12 Pa in the oscillation frequency sweep test, whereas G’ of 4%bentonite/0.5%PAC suspension was nearly 5 Pa. Particularly, 0.5 wt.% PAC /Laponite suspensions could maintain higher gel structure, yield point and better shear-thinning behaviors after 120°C hot rolling. The TEM image revealed that nanoscaled Laponite could form a “star network” with PAC in water, which explained the good rheological properties of PAC/LAP mixed suspensions. Besides, in the weighted drilling fluids, 1 wt.% Laponite could maintained a much higher gel strength compared with 4 wt.% bentonite.As the unique rheological properties, Laponite nanoparticles can greatly enhance abilities of water-based drilling fluids in circulating cuttings and making the borehole clean.

scholarly journals Rheological Properties Related to Extrusion of Polyolefins

Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 489
Author(s):  
Evan Mitsoulis ◽  
Savvas G. Hatzikiriakos
Keyword(s):  
Rheological Properties ◽  
Slip Velocity ◽  
Wall Slip ◽  
Molecular Characteristics ◽  
Capillary Rheometer ◽  
Rheological Models ◽  
Cross Model ◽  
Slip Effects ◽  
Best Fitting ◽  
Temperature And Pressure

Rheological properties related to the extrusion of polyolefins are the shear viscosity, the elongational viscosity, the slip velocity and their temperature- and pressure-dependencies. These properties are measured in the rheology lab mainly via a parallel-plate rheometer and a capillary rheometer. Then appropriate rheological models have to be used to account for all these properties. Such models are either viscous (e.g., the Cross model) or viscoelastic (e.g., the K-BKZ model). The latter gives the best fitting of the experimental data and offers excellent results in numerical simulations, especially in extrusion flows. Wall slip effects are also found and measured by rheometric flows. Modeling of extrusion flows should make use of appropriate slip models that take into effect the various slip parameters, including the effects of shear stress, molecular characteristics, temperature and pressure on the slip velocity. In this paper the importance of these properties in extrusion are discussed.

Study on the Rheological Properties of PTFE/PVA Blended Solution

2011 ◽  
Vol 233-235 ◽  
pp. 2934-2937
Author(s):  
Yao Wu Wang ◽  
Run Jun Sun ◽  
Zhao Huan Zhang ◽  
Li Ping Chen ◽  
Mu Yao
Keyword(s):  
Shear Rate ◽  
Rheological Properties ◽  
Apparent Viscosity ◽  
Shear Thinning ◽  
Shear Thinning Fluid

PTFE suspension latex and PVA solution are blended at different ratio, and the rotary rheometer is used to test the rheological properties of these solutions. The result shows that both PTFE suspension latex and PTFE/PVA blended solution are all shear thinning fluid; with increasing shear rate, apparent viscosity decreases; with increase of PVA content in blended solution, apparent viscosity and Non-Newtonian index increase, and spinnability of blended solution can be improved; with increase of temperature, the apparent viscosity decreases.

Numerical Analysis of Wall Slip Effects on Flow of Newtonian and Non-Newtonian Fluids in Macro and Micro Contraction Channels

2006 ◽  
Vol 129 (1) ◽  
pp. 23-30 ◽  
Author(s):  
Alfeus Sunarso ◽  
Takehiro Yamamoto ◽  
Noriyasu Mori
Keyword(s):  
Shear Stress ◽  
Shear Rate ◽  
Wall Shear Stress ◽  
Newtonian Fluid ◽  
Stress Function ◽  
Slip Velocity ◽  
Wall Slip ◽  
Average Shear ◽  
Wall Shear ◽  
Shear Stress Function

We performed numerical simulation to investigate the effects of wall slip on flow behaviors of Newtonian and non-Newtonian fluids in macro and micro contraction channels. The results show that the wall slip introduces different vortex growth for the flow in micro channel as compared to that in macro channel, which are qualitatively in agreement with experimental results. The effects of slip on bulk flow behaviors depend on rheological property of the fluid. For Newtonian fluid, the wall slip always reduces the vortex length, while for non-Newtonian fluid, the strength of the slip determines whether the vortex length is reduced or increased. Analyses on the velocity and stress fields confirm the channel size dependent phenomena, such as the reduction of wall shear stress with the decrease in channel size. With the increase in average shear rate, the Newtonian fluid shows the reduction of wall shear stress that increases in the same trend with slip velocity-wall shear stress function, while for non-Newtonian fluid, the effect of the slip is suppressed by shear thinning effect and, therefore, the reduction of wall shear stress is less sensitive to the change in average shear rate and slip velocity-wall shear stress function.

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