scholarly journals Impact of Clay Minerals on the Dewatering of Coal Slurry: An Experimental and Molecular-Simulation Study

Minerals ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 400 ◽  
Author(s):  
Xiaomin Ma ◽  
Yuping Fan ◽  
Xianshu Dong ◽  
Ruxia Chen ◽  
Hongliang Li ◽  
...  
Keyword(s):  
Clay Minerals ◽  
Filter Cake ◽  
Specific Resistance ◽  
Filtration Velocity ◽  
Coal Slurry ◽  
Edge Surface ◽  
Adsorption Density ◽  
Coal Tailings ◽  
Filter Cakes ◽  
Density Of Water

The cleaning process of coals is challenging due to the existence of clay minerals. The overall objective of this study is to investigate how the dewatering of coal slurry is impacted by the presence of clay minerals, i.e., kaolinite and montmorillonite. Filtration tests were first conducted to investigate the effect of kaolinite and montmorillonite on the dewatering efficiency of coal. Specifically, we measured the filtration velocity, moisture, average specific resistance, and porosity of filter cakes for six slurry samples, in which different amounts of kaolinite and montmorillonite were contained. Filtration tests show that a small amount of kaolinite and montmorillonite leads to a significant reduction in the filtration velocity and porosity, and a big increase in the average specific resistance and the moisture of the filter cake. We observe that most kaolinite existed in the top and middle layers of the filter cake, while most montmorillonite existed in the top layer; on the contrary, little montmorillonite is observed in the middle and bottom layers of the filter cake. Montmorillonite results in a much more deteriorative effect than kaolinite. Considering that the interactions between clay minerals and water may play a key role, we then further investigate the effect of such interactions using molecular simulations. Simulation results show that water molecules could hardly diffuse into kaolinite from the edge, while they could readily penetrate into the montmorillonite layers from the edge surface. This result can be explained by the hydrated cation in montmorillonite. The adsorption density of water on the octahedral surface of kaolinite is higher than that of water on the tetrahedral surface of kaolinite. Furthermore, the adsorption density of water on the double surfaces of kaolinite is higher than that of water on the montmorillonite surface. This research is expected to provide benefits or contributions to the dewatering of clay-rich coal tailings.

Pore structure and permeability of filter cake in coal slurry filtration

2019 ◽  
pp. 1-16
Author(s):  
Qiming Zhuo ◽  
Donghui Wang ◽  
Hongxiang Xu ◽  
Wenli Liu ◽  
Liang Gao
Keyword(s):  
Pore Structure ◽  
Filter Cake ◽  
Coal Slurry

scholarly journals Test Study on Airtight Capability of Filter Cakes for Slurry Shield and Its Application in a Case

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Fanlu Min ◽  
Wei Zhu ◽  
Shengquan Xia ◽  
Rui Wang ◽  
Daiwei Wei ◽  
...  
Keyword(s):  
Yangtze River ◽  
Filter Cake ◽  
Water Pressure ◽  
Air Pressure ◽  
Test Results ◽  
Test Study ◽  
Capillary Bundle ◽  
Slurry Shield ◽  
Filter Cakes ◽  
The Relationship

To learn the airproof capacity of filter cakes as opening chambers under air pressure, a series of tests were carried out. The variations of discharged water with air pressure and time were observed, and the relationship between airproof capacity of filter cakes and surrounding air pressure was analysed. The test results indicated that there were three stages as compressed air acting on filter cakes: completely not infiltration, a very small amount of infiltration, and penetration leakage. The certain air pressure between the first and second stages was called the airproofing value of filter cake. And a capillary bundle model was used to explain the mechanism of air tightness of filter cakes. In Nanjing Yangtze River Tunnel, a 5 cm thickness filter cake was formed in gravel sand, and its airproofing value was a little lower than 0.12 MPa. The air pressure used as opening chamber should be equal to the summation of water pressure in sand and airproofing value of filter cake. While the air pressure is larger than the summation, the filter cake would be gas permeable. The slurry formulation and airproofing value of filter cakes obtained in the tests were applied successfully in Nanjing Yangtze River Tunnel.

Mechanics of Static and Dynamic Filtration In the Borehole

1963 ◽  
Vol 3 (03) ◽  
pp. 236-244 ◽  
Author(s):  
H.D. Outmans
Keyword(s):  
Porous Medium ◽  
Filtration Rate ◽  
Filter Cake ◽  
Fluid Pressure ◽  
Rate Of Change ◽  
Filtration Theory ◽  
Dynamic Conditions ◽  
Dynamic Filtration ◽  
Static Conditions ◽  
Filter Cakes

Abstract The mechanics of filtration are described by a theoretical-empirical nonlinear diffusion equation which, under certain circumstances, may be linearized and then solved explicitly.For filtration under static conditions linearization leads to a boundary value problem analogous to a heat flow problem with a known explicit solution. The corresponding solution for static filtration is compared with published experimental data.Under dynamic conditions filtration takes place in three successive stages. During each of these the rate of filtration and/or the thickness of the filter cake are different functions of the filtration time. The proposed mechanism explains the observed high resistance of dynamically deposited filter cakes against erosion and also the connection between filtration rate and viscosity of the drilling fluidSeveral of the quantities governing dynamic filtration have no counterpart in the static filtration mechanism. The static filtration rate is, therefore, not a reliable measure for the dynamic rate and vice versa. Introduction Filtration under simulated borehole conditions, i.e., either from a static suspension or from a suspension flowing parallel to the filter cake (dynamic filtration), has been the subject of several laboratory studies. This experimental and theoretical work showed that many aspects of the filtration mechanism cannot be explained by an elementary filtration theory based on the assumption that the filter cake is incompressible. For a more satisfactory theory compressibility should be taken into account. This has been done, at least to some extent, in the filtration theory developed for the chemical industry. Surveying the literature (see Ref. 8 for a bibliography) it becomes apparent that, although several properties of filter cakes deposited from many different suspensions have been measured, including compressibility, the filtration equations are essentially empirical in nature. No attempt has been made, for instance, to develop filtration theory along the lines of consolidation theory. This theory, upon which a highly successful development in soil mechanics rests, would appear to be an excellent starting point for a filtration theory since the compressibility concept is an essential part of it. As we will use this theory in the following development it is well to state the four assumptions on which it is based:The fluid flow through a compressible porous medium is governed by Darcy's law.The rate of change in fluid content of an element of the porous medium is proportional to the rate of change of solid pressure between the particles.The solid particles are incompressible within the range of pressures considered.The total pressure on a surface normal to the line of flow is equal to the sum of the fluid pressure and the pressure between the particles (solid pressure) at that surface. To calculate the rate of filtration and other quantities of interest it is necessary to know the filter cake compressibility and the permeability as a function of the solid pressure. It has not been possible to calculate these functions from theoretical considerations and they will therefore be introduced in this paper as empirical expressions. Both are determined in a compression cell where the cake is subjected to a mechanical load. Permeability and compressibility are measured after the solid pressure has stabilized, i.e., after the excess fluid pressure has been dissipated and the uniform pressure is transmitted entirely by the solids.The permeability and compressibility thus determined are not the same as during filtration in the borehole, under either static or dynamic conditions, because then, due to frictional drag, the solid pressure and hence also the permeability and compressibility vary along a line normal to the direction of the mean flow and can only be defined locally. DERIVATION OF THE FILTRATION EQUATION FOR COMPRESSIBLE FILTER CAKES As the filter cake in the borehole is thin compared to the radius of the hole the filtration may be considered as linear. Taking the x-axis normal to the wall, with its origin at the formation, we have, according to Darcy's law, ...........................(1) SPEJ P. 236^

scholarly journals Tuning the chemistry of seawater with activated clay: an application in SmartWater enrichment for enhanced oil recovery

2020 ◽  
Vol 10 (8) ◽  
pp. 3905-3916
Author(s):  
Jimoh K. Adewole ◽  
Taye S. Kazeem ◽  
Tajudeen A. Oyehan
Keyword(s):  
Crude Oil ◽  
Transport Properties ◽  
Enhanced Oil Recovery ◽  
Oil Recovery ◽  
Filter Cake ◽  
Oil Reservoir ◽  
Mixed Matrix ◽  
Ion Rejection ◽  
Filter Cakes

Abstract Studies on the interaction between crude oil, brine, and rock systems showed that the composition of water injected into the oil reservoir influences the amount of oil recovered from such a reservoir. Therefore, researchers are now emphasizing the use of SmartWater for enhanced oil recovery (EOR). In this research, the capability of activated clay to be used for tuning the chemistry of seawater for subsequent production of SmartWater was investigated. Filter cakes were formed using bentonite and its blends with raw clay and activated clay (which was produced in-house using locally obtained clay samples). The capability of the cakes to control the transport properties of permeating seawater was evaluated in terms of ion rejection. The average rejection for the raw clay cake for Na+, K+, Mg2+, and Ca2+ is 4.45, 49.64, 53.33, and 94.43%, respectively. The rejection results for the mixed-matrix cake containing the activated clay were 6.38, 51.34, 86.19, and 78.09 for Na+, K+, Mg2+, and Ca2+, respectively. It was observed that the selectivity of the filter cake for Mg2+ and Ca2+ was reversed due to the addition of the activated clay. Thus, activated clay possesses some potentials for SmartWater production for an EOR application.

scholarly journals Unravelling colloid filter cake motions in membrane cleaning procedures

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Arne Lüken ◽  
John Linkhorst ◽  
Robin Fröhlingsdorf ◽  
Laura Lippert ◽  
Dirk Rommel ◽  
...  
Keyword(s):  
Laser Scanning ◽  
Filter Cake ◽  
Membrane Surface ◽  
Cross Flow ◽  
Laser Scanning Confocal Microscopy ◽  
Scanning Confocal Microscopy ◽  
Filtration Performance ◽  
Dynamic Mobility ◽  
Cake Layer ◽  
Filter Cakes

AbstractThe filtration performance of soft colloid suspensions suffers from the agglomeration of the colloids on the membrane surface as filter cakes. Backflushing of fluid through the membrane and cross-flow flushing across the membrane are widely used methods to temporally remove the filter cake and restore the flux through the membrane. However, the phenomena occurring during the recovery of the filtration performance are not yet fully described. In this study, we filtrate poly(N-isopropylacrylamide) microgels and analyze the filter cake in terms of its composition and its dynamic mobility during removal using on-line laser scanning confocal microscopy. First, we observe uniform cake build-up that displays highly ordered and amorphous regions in the cake layer. Second, backflushing removes the cake in coherent pieces and their sizes depend on the previous cake build-up. And third, cross-flow flushing along the cake induces a pattern of longitudinal ridges on the cake surface, which depends on the cross-flow velocity and accelerates cake removal. These observations give insight into soft colloid filter cake arrangement and reveal the cake’s unique behaviour exposed to shear-stress.

Degrading Drilling Fluid Filter Cake Using Effective Microorganisms

2012 ◽  
pp. 1-22
Author(s):  
Issham Ismail ◽  
Rosli Illias ◽  
Amy Shareena Abd. Mubin ◽  
Masseera Machitin
Keyword(s):  
Surface Tension ◽  
Room Temperature ◽  
Filter Cake ◽  
Drilling Fluid ◽  
Filter Press ◽  
Fluid Loss ◽  
Effective Microorganisms ◽  
Cleaning Solution ◽  
Viscoelastic Surfactant ◽  
Filter Cakes

The effective cleanup of filter cakes in long, horizontal open-hole completions can maximize an oil well’s productivity. A cleaning solution was formulated which comprised effective microorganisms and a viscoelastic surfactant in order to degrade filter cakes of water-based mud. Generally, the effectiveness of the microorganisms in degrading filter cakes is influenced by temperature and its concentration. To overcome the problem, the viscoelastic surfactant has been used to extend the application of temperature range and increase the viscosity of the cleaning solution. Laboratory studies were conducted to examine the effectiveness of the microorganisms in degrading filter cakes. The apparent viscosity of cleaning solution was measured as a function of shear rate (102.2 s and 1022 s ) and temperature (25 to 80°C). The surface tension of the cleaning solution was measured at room temperature. Static fluid loss tests were performed using the HPHT Filter Press in order to determine the effectiveness of the cleaning solution in degrading filter cake at different temperatures ranging from 100°F to 300°F. Experimental results showed that the cleaning solution could effectively degrade the filter cake. Soaking process was performed until 48 hours and it showed that at temperature 200°F and below, the pure effective microorganisms achieved the highest efficiency of filter cake degradation, i.e. 34.9%. However, at temperature 300°F, cleaning solution that contained effective microorganisms and higher concentration of viscoelastic surfactant was found to perform better. The viscoelastic surfactant succeeded in increasing the viscosity of the cleaning solution, thus enhanced the rate of degradation of filter cakes, i.e. 33.4% at 300°F. The surface tension of the cleaning solution did not change significantly at various concentrations at room temperature.

scholarly journals Deposition Thickness Modeling and Parameter Identification for a Spray-Assisted Vacuum Filtration Process in Additive Manufacturing

2016 ◽  
Vol 139 (4) ◽  
Author(s):  
August Mark ◽  
Yunjun Xu ◽  
Jihua Gou
Keyword(s):  
Additive Manufacturing ◽  
Electrical Properties ◽  
Filter Cake ◽  
Optimization Approach ◽  
Unknown Parameters ◽  
Filtration Process ◽  
Nonlinear Constrained Optimization ◽  
Vacuum Filtration ◽  
Materials Used ◽  
Filter Cakes

To enhance mechanical and/or electrical properties of composite materials used in additive manufacturing, nanoparticles are oftentimes deposited to form nanocomposite layers. To customize the mechanical and/or electrical properties of the final composite material, the thickness of such nanocomposite layers must be precisely controlled. A thickness model for filter cakes created through spray-assisted vacuum filtration is presented in this paper, to enable the development of advanced thickness controllers. The mass transfer dynamics in the spray atomization and vacuum filtration are studied to derive solid mass, water mass, and filter cake thickness differential area models. A two-loop nonlinear constrained optimization approach is used to identify the unknown parameters in the model. Experiments involving depositing carbon nanofibers in a sheet of filter paper are used to measure the ability of the model to mimic the filtration process.

Investigation of Drilling Fluids Containing Blast Furnace Slag for Their Potential Impact on Formation Damage—A Laboratory Study

1999 ◽  
Vol 121 (3) ◽  
pp. 149-153 ◽  
Author(s):  
U. A. Tare ◽  
N. E. Takach ◽  
S. Z. Miska ◽  
F. B. Growcock ◽  
N. Davis
Keyword(s):  
Blast Furnace ◽  
Blast Furnace Slag ◽  
Filter Cake ◽  
Drilling Fluid ◽  
Rapid Development ◽  
Formation Damage ◽  
Drilling Fluids ◽  
Filter Cakes ◽  
The Impact ◽  
Furnace Slag

This work discusses the effect of incorporating blast furnace slag (BFS) as an additive in water-based drilling fluids. The intent of this treatment is rapid development of a thin, impervious, and easily removable filter cake, thereby minimizing detrimental impact of the drilling fluid on formation productivity as opposed to previous applications of BFS in universal fluids. To evaluate the impact of BFS on filter cake properties, permeability plugging apparatus (PPA) tests and dynamic formation damage (DFD) studies were conducted. Drill-in fluids and dispersed muds were tested using varying quantities of BFS. Once a steady rate of dynamic filter cake deposition was achieved, the BFS in the filter cakes was chemically activated. The results obtained from these activation studies were compared with those obtained with no BFS and with unactivated BFS. The nature of the filter cakes was examined with an environmental scanning electron microscope (ESEM). Results obtained from the PPA tests indicate substantial decreases in initial spurt loss and filtrate volume with increasing concentration of BFS. The DFD studies substantiate the aforementioned observations and show enhancement of return permeabilities with BFS activation. ESEM studies demonstrate that BFS can consolidate filter cakes.

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