Surface physical properties and its effects on the wetting behaviors of respirable coal mine dust

Li, Qingzhao; Lin, Baiquan; Zhao, Shuai; Dai, Huaming

doi:10.1016/j.powtec.2012.08.023

Cited by 159 publications

(53 citation statements)

References 18 publications

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“…From the above analysis, it is found that the total surface area of droplet becomes larger with the increase of r. When a water drop with a volume of V is split into lots of droplets and made each droplet equal volume, the total surface area would be S t ¼ ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi ffi 36nπV 2 3 p , in which n is the number of all droplets. Therefore, if a water drop is divided into n droplets, the total surface area of a water drop will increase the amount of ffiffi ffi n 3 p [17].…”

Section: Results Analysis and Dust-fall Theory Of Fine Dropletsmentioning

confidence: 99%

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Wetting Behavior of Hydrophobic Dust and Dust-Fall Theory of Fine Droplets

Kou

Qiuzu

2015

Braz J Phys

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The wetting behavior of droplets on the surfaces of hydrophobic coal slices is measured with a CCD camera and simulated with the volume of fluid (VOF) numerical method. Experimental results reveal that the contact angle changes exponatially with time and the wettability decreases with the increasing rough microstructures of coal slice surfaces. There is a good agreement between numerical simulations and experimental results. Meanwhile, it is found that droplet with a smaller volume can enhance the hydrophilic. The dust-fall theory of fine droplets is useful to improve the wettability of dust and enlarge the contact ratio between dust and droplets, which can help to design wet-type dust-fall equipment and provide new way for the control of respiratory dust.

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Section: Results Analysis and Dust-fall Theory Of Fine Dropletsmentioning

confidence: 99%

“…At present, water for its dust wetting properties is often used to be a major means to reduce dust. The wetting behavior between droplet and dust determines the dust control efficiency, especially for hydrophobic surface of almost all kinds of coal, which is more difficult to be wetted [3][4][5].…”

Section: Introductionmentioning

confidence: 99%

Wetting Behavior of Hydrophobic Dust and Dust-Fall Theory of Fine Droplets

Kou

Qiuzu

2015

Braz J Phys

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“…The high degree roughness of the channel wall in the dull banded region, shown in Figure 3A and B, creates macroscale variation in the fluid-sollid contact and this leads to large uncertainties in the contact angles determined in the CFC or by other methods (Li et al 2013, Susana, Campaci, and Santomaso 2012. 2.…”

Section: Contact Angles Measured During Imbibitionmentioning

confidence: 99%

The Effect of Rank and Lithotype on Coal Wettability and its Application to Coal Relative Permeability Models

et al. 2015

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We report the effect of rank and lithotype on the wettability of artificial cleat channels in five coals from the Bowen Basin with ranks in the R max% range 0.98-1.91%. Wettability was assessed by measuring contact angles of air and water in the artificial cleats using a microfluidic Cleat Flow Cell (CFC) instrument. The artificial cleats were produced by reactive ion etching and had widths in the range 20 -40 m that replicate the width and shape of some natural coal cleats under sub-surface reservoir conditions. These model cleats were developed to allow systematic laboratory investigations of water and gas relative permeability behaviour.Imbibition and drainage experiments were performed in the artificial channels using air and 0.1 %wt. fluorescein in fresh tap water to observe contact angles, the entry pressure of the air-water and water-air interface to the channel, and the pressure at which the channel was filled by the displacing fluid. Relative contact angles on the coal surface of 110 -140°were determined from images collected in the imbibition experiments. A trend of increasing contact angle with coal rank was observed. The low rank coal exhibited smaller contact angles and lower breakthrough pressures than the higher rank coal samples. In the drainage experiments the injection air displaced the water but left a residual liquid film on cleat walls across dull, inertinite rich bands. This residual film was not observed in the bright, vitrinite rich bands. The results of this study may provide the basis to consider an improved relative permeability model that explicitly accounts for wettability and the effect of coal rank. Figure 7-A) Reactive Ion Etched vitrinite rich wall. B) RIE inertinite rich wall. Both samples were titled 45°to capture the images.

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“…Adding a surfactant in water as a dust control method can effectively improve the dust suppression efficiency and has become an important approach to control coal dust in Europe and the United States. is is because a surfactant can significantly reduce the surface tension of a solution and effectively wet the dust surface [15,16], leading to dust agglomeration and settling, thereby achieving the effect of dust suppression. erefore, selecting a suitable surfactant is the key factor to improve the effect of the spray dustfall [13].…”

Section: Introductionmentioning

confidence: 99%

Wetting Process and Adsorption Mechanism of Surfactant Solutions on Coal Dust Surface

Wang

Yuan

Jiang

2019

Journal of Chemistry

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To determine the wetting process and wetting mechanism of different surfactant solutions on coal dust surface, four types of surfactants (anionic surfactant 1227, anionic surfactant AOS, amphoteric surfactant CAB-35, and nonionic surfactant CDEA) are selected to measure their surface tension and contact angle. Based on the data, the adhesion work, spreading coefficient, and immersion work of the surfactant solutions on a coal dust surface are calculated and their adsorption mechanism is discussed. e results show that the surface tension and contact angle of AOS and CDEA are lower and smaller, respectively, their calculated spreading coefficients are higher, and their adhesion work and immersion work are less than those of 1227 and CAB-35. is shows that the wettability of the AOS and CDEA solutions for a coal dust surface is more than that of 1227 and CAB-35, whereas their adhesion is lower than that of the latter. e spreading coefficient can be used as an index to determine the wettability. e wetting ability of the AOS and CDEA aqueous solutions for coal dust is stronger than that of 1227 and CAB-35 because of the different adsorption forms of the surfactant molecules on the surface of the coal dust. e tail hydrophobic group of the AOS and CDEA surfactant molecules orient to the surface of the coal dust, whereas the head hydrophilic group directs to the solution, being easier to wet. e results show that anionic and nonionic surfactant solutions can significantly improve the wettability of a coal dust surface, providing a theoretical basis for selecting suitable surfactants as water-spray additives to improve the dust suppression efficiency.

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Surface physical properties and its effects on the wetting behaviors of respirable coal mine dust

Cited by 159 publications

References 18 publications

Wetting Behavior of Hydrophobic Dust and Dust-Fall Theory of Fine Droplets

Wetting Behavior of Hydrophobic Dust and Dust-Fall Theory of Fine Droplets

The Effect of Rank and Lithotype on Coal Wettability and its Application to Coal Relative Permeability Models

Wetting Process and Adsorption Mechanism of Surfactant Solutions on Coal Dust Surface

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