scholarly journals An Experimental Study on Wetting of Coal Dust by Surfactant Solution

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Yidan Jiang ◽  
Pengfei Wang ◽  
Ronghua Liu ◽  
Ye Pei ◽  
Gaogao Wu
Keyword(s):  
Surface Tension ◽  
Contact Angle ◽  
Reverse Osmosis ◽  
Sodium Sulfate ◽  
Moisture Absorption ◽  
Coal Dust ◽  
Pure Water ◽  
Surfactant Solution ◽  
Limited Range ◽  
Dust Reduction

Surfactants can improve the wetting performance of the dust-reduction spraying water, thus improving the dust-reduction effect by spray. In this study, the performance of surfactant solution in wetting coal dust was investigated through experiments. In addition, the effects of surfactant type, mass fraction, metamorphic degree of coal, particle size, and additives were investigated. According to the results of surface tension experiments, the surface tension of the solution decreased with the increase of the concentration of surfactant. However, after reaching CMC, the surface tension did not have significantly decrease. SDBS and OP-10 had higher efficiency in decreasing the surface tension than the other two types of surfactants. The addition of sodium sulfate additives can further reduce the surface tension of the surfactant solution by a limited range. The coal dust wetting experiment showed that with the increase in the concentration of the surfactant, the contact angle of the droplets on the coal dust tablet was continuously reduced, and the wettability of the solution was continuously improved. The wettability of the OP-10 solution was optimal. At the same concentration, the minimum contact angle can be obtained in the OP-10 solution. As the contact angle of the coal dust increased, the growth rate in the coal dust reverse osmosis moisture absorption of the surfactant solution relative to the pure water increased. After the addition of sodium sulfate, the reverse osmosis moisture absorption of coal dust increased to varying degrees. In addition, as the concentration of additives increased, the moisture absorption of coal dust increased.

scholarly journals Experimental Investigation of Coal Dust Wettability Based on Surface Contact Angle

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Gang Zhou ◽  
Han Qiu ◽  
Qi Zhang ◽  
Mao Xu ◽  
Jiayuan Wang ◽  
...  
Keyword(s):  
Surface Tension ◽  
Contact Angle ◽  
Specific Surface ◽  
Coal Dust ◽  
Single Point ◽  
Contact Angles ◽  
Critical Surface ◽  
Volume Percentage ◽  
Surface Areas ◽  
Specific Surface Areas

Wettability is one of the key chemical properties of coal dust, which is very important to dedusting. In this paper, the theory of liquid wetting solid was presented firstly; then, taking the gas coal of Xinglongzhuang coal mine in China as an example, by determination of critical surface tension of coal piece, it can be concluded that only when the surface tension of surfactant solution is less than 45 mN/m can the coal sample be fully wetted. Due to the effect of particle dispersity, compared with the contact angle of milled coal particle, not all the contact angles of screened coal powder with different sizes have a tendency to increase. Furthermore, by the experiments of coal samples’ specific surface areas and porosities, it can be achieved that the volume of single-point total pore decreases with the gradual decreasing of coal’s porosity, while the ultramicropores’ dispersities and multipoint BET specific surface areas increase. Besides, by a series of contact angle experiments with different surfactants, it can be found that with the increasing of porosity and the decreasing of volume percentage of ultramicropore, the contact angle tends to reduce gradually and the coal dust is much easier to get wetted.

Experimental Investigation of Low Weber Number Post-Impact Drop Spreading on Solid Substrates

2010 ◽  
Author(s):  
Milind A. Jog ◽  
Raj M. Manglik
Keyword(s):  
Surface Tension ◽  
High Speed ◽  
Pure Water ◽  
Surfactant Solution ◽  
Video Camera ◽  
Dynamic Surface Tension ◽  
Temporal Variations ◽  
Dynamic Surface ◽  
Post Impact ◽  
Triton X

The post-impact spreading and recoil behaviors of droplets of pure liquids (water and ethanol) and aqueous solution of Triton X-100 (a surfactant) on a dry horizontal hydrophilic (glass) substrate are investigated for low Weber numbers. The evolution of drop shape during spreading and recoil are captured using a high-speed (4,000 frames per second) digital video camera. Digital image-processing was used to determine the spread and height of the liquid film on the surface from each frame. Unlike pure liquids, the liquid-gas interfacial tension for surfactant solution is a function of surface age, where surface tension is that of the solvent at zero time and then reaches an equilibrium value with increasing surface age. Furthermore, the equilibrium surface tension is a function of the surfactant concentration, which decreases from that of the solvent at zero concentration to that at the critical micelle concentration (CMC), and remains essentially constant thereafter. The surface tension of aqueous Triton X-100 solution varies from that of pure water to nearly that of ethanol. As such the comparison of transient droplet-impact-spreading-recoil behavior of the three liquids, or their temporal variations of the spread and the flattening factor, provides a basis for understanding the role of dynamic surface tension and surface wettability.

Effects of Surface Tension and Binary Diffusion on Pool Boiling of Dilute Solutions: An Experimental Assessment

1999 ◽  
Vol 121 (2) ◽  
pp. 488-493 ◽  
Author(s):  
S. G. Kandlikar ◽  
L. Alves
Keyword(s):  
Heat Transfer ◽  
Surface Tension ◽  
Contact Angle ◽  
Heat Transfer Coefficient ◽  
Boiling Heat Transfer ◽  
Pure Water ◽  
Pool Boiling ◽  
Binary Diffusion ◽  
Water Value ◽  
Diffusion Effects

Pool boiling heat transfer with dilute binary mixtures introduces two additional effects due to binary diffusion, and due to change in the surface tension. The secondary effects due to changes in contact angle and wetting characteristics may also play a role. The present study focuses on identifying these effects for dilute aqueous solutions of ethylene glycol. Pool boiling experiments are conducted to generate data in the range of one to ten percent mass fraction. It is found that in the low concentration region, the binary diffusion effects are insignificant for aqueous solutions of ethylene glycol, and a slight improvement in heat transfer coefficient is observed over the pure water value. The binary diffusion effects are related to a volatility parameter, V1. The heat transfer coefficient does not degrade in the region where V1 < 0.03, and the surface tension does not change appreciably compared to pure water value. This points to the possibility that the changes in contact angle and wetting characteristics play an important role in the pool boiling heat transfer.

Synthesis and Characterization of a Novel Class of Zwitterionic Fluorocarbon Surfactants Based on Perfluorobutyl

2021 ◽  
Vol 58 (2) ◽  
pp. 136-145
Author(s):  
Xuhong Jia ◽  
Rui Huang ◽  
Xiaoguang Yang ◽  
Wan Tao ◽  
Xinhua Zhu
Keyword(s):  
Surface Tension ◽  
Surface Activity ◽  
High Efficiency ◽  
Pure Water ◽  
Surfactant Solution ◽  
Carbon Chain ◽  
Surfactant Solutions ◽  
Minimum Surface Tension ◽  
Fluorocarbon Chain ◽  
Ph Range

Abstract Perfluorooctane sulfonate (PFOS) and its derivatives had been banned due to their potential environmental hazards, although they possessed excellent surface activity. An effective method to solve this problem was to shorten the fluorocarbon chain of these surfactants from C°H17 to C4F9. As previous studies had shown, zwitterionic surfactants possess higher surface activity but have lower toxicity compared to other types of surfactants. In view of this, a class of novel zwitterionic fluorocarbon surfactants (n-CFNA-Br) with perfluorobutyl moiety was synthesized in this work. Their structures were characterized by FTIR, 1H NMR, 13C NMR, 19F NMR and MS. The results showed that all synthesized n-CFNA-Br had almost the same minimum surface tension, but their critical micelle concentration (CMC) decreased with increasing length of hydrophobic carbon chain. In pure water, the surface tension at the CMC (γCMC) of the four n-CFNA-Br were about 20 mN/m, and the CMC values were 7.73 mmol/L for 1-CFNA-Br, 4.70 mmol/L for 2-CFNA-Br, 4.13 mmol/L for 3-CFNA-Br, and 3.36 mmol/L for 4-CFNA-Br, indicating high efficiency and effectiveness. In 0.1 mol/L NaCl, the CMC values reduced to less than half of the CMC values measured in the pure aqueous surfactant solution, while the surface tensions γCMC remained almost unchanged, indicating good salinity tolerance of the synthesized surfactants. The acidic surfactant solutions exhibited similar CMC values to the saline solutions, but the surface tension γCMC increased slightly to 25 mN/m. However, further investigation showed that the n-CFNA-Br surfactants exhibited poor surface activity in alkaline solution (0.1 mol/L NaOH). In the pH range of 6.6 to 10.4, white precipitates appeared in the surfactant solutions after some time, indicating that the n-CFNA-Br are not suitable for use in alkaline systems with pH greater than 6.6.

scholarly journals Preparation and performance analysis of a coking coal dust suppressant spray

2021 ◽  
Author(s):  
Jiuhong Jiang ◽  
Pengfei Wang ◽  
Ye Pei ◽  
Ronghua Liu ◽  
Liming Liu ◽  
...  
Keyword(s):  
Reverse Osmosis ◽  
Moisture Absorption ◽  
Coal Dust ◽  
Sodium Dodecyl ◽  
Sodium Dodecyl Benzene Sulfonate ◽  
Absorption Capacity ◽  
Orthogonal Experimental Design ◽  
Coking Coal ◽  
Dodecyl Benzene Sulfonate ◽  
And Performance

Abstract Coking coal dust is extremely hydrophobic; therefore, combination with droplets in the air is difficult and dust suppression is challenging. Here, a dust suppressant spray for coking coal dust was studied in order to improve of the combination of droplets and coking coal dust. Based on monomer optimization and compounding analysis, two surfactant monomers, fatty alcohol ether sodium sulfate (AES) and sodium dodecyl benzene sulfonate (SDBS) were selected as the surfactant components of the dust suppressant. The surfactant monomers were combined with four inorganic salts and the reverse osmosis moisture absorption of each solution was determined. By combining the reverse osmosis moisture absorption values with the water retention experimental results, CaCl2 was identified as the optimal inorganic salt additive for the dust suppressant. Finally, the optimal concentration of each component was obtained using orthogonal experimental design i.e., AES (0.03%), SDBS (0.05%), and CaCl2 (0.4%). The dust suppressant solution formulated using this method had a high moisture absorption capacity and excellent performance. Graphic Abstract

scholarly journals A contact angle study of different greywater sources with hydrophobic membranes

2020 ◽  
Vol 55 (3) ◽  
pp. 310-326
Author(s):  
Mohammad Ramezanianpour ◽  
Muttucumaru Sivakumar ◽  
Natalie Osborn ◽  
Ying Zhang ◽  
Hakim Kawa
Keyword(s):  
Surface Tension ◽  
Contact Angle ◽  
Pure Water ◽  
Membrane Distillation ◽  
Hydrophobic Membrane ◽  
Flat Sheet ◽  
Hydrophobic Membranes ◽  
Different Types ◽  
The Impact ◽  
Surface Tension Forces

Abstract The wetting phenomenon is a major problem in the membrane distillation (MD) process, and it is the main reason that limits MD being used in wastewater reclamation. Active surfactant in the detergents reduces the contact angle between the liquid and the hydrophobic membrane surface, which could result in wetting. Extensive laboratory research was conducted using commercial hydrophobic flat-sheet membranes to identify the impact of anionic surfactants and surface tension forces on these membranes. The aim of this paper is to find a suitable membrane for pure water production from greywater using MD, as well as to provide a relationship between surfactant concentration and the contact angle for different types of membrane. The absorbance of each sample was measured by a spectrophotometer prior to the contact angle test on four different types of hydrophobic membranes. It was concluded that the polypropylene membrane would be unsuitable for the treatment of greywater directly due to the loss of surface tension forces upon the addition of an anionic surfactant. However, the polytetrafluoroethylene membrane could be effective in this process while the concentration of surfactant in the feed source is kept constant. The results from the experimental tests proposed a relationship between the contact angle of a water droplet on the surface of a flat-sheet membrane and the concentration of surfactant in the solution.

Study of Influence Factors on Wettability of Coal Dust

2013 ◽  
Vol 724-725 ◽  
pp. 1050-1053
Author(s):  
Yin Yu Sun ◽  
Rong Chun Nie ◽  
Lin Lin Zhang
Keyword(s):  
Surface Tension ◽  
Contact Angle ◽  
Fourier Transform ◽  
Coal Dust ◽  
Sodium Dodecyl ◽  
Influence Factors ◽  
Sodium Dodecyl Benzene Sulfonate ◽  
Tween 80 ◽  
Benzene Sulfonate ◽  
Dodecyl Benzene Sulfonate

In this study, coal samples of experimental come from the raw coal of Wangfenggang and Qidong. Sodium dodecyl benzene sulfonate (SDBS), sodium dodecyl sulfate (SDS), water-reducing admixture NF and Tween-80 are choosed as surfactants. The influence factors on wettability of coal dust were characterized by contact angle meter, fourier transform infrared spectroscopy (FTIR) and surface tension experiment. The research shows that the effect of solution on wettability of coal dust is mainly depended on the surface structure of coal dust, type and concentration of solution.

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

2019 ◽  
Vol 2019 ◽  
pp. 1-9
Author(s):  
Xiaonan Wang ◽  
Shujie Yuan ◽  
Bingyou Jiang
Keyword(s):  
Surface Tension ◽  
Contact Angle ◽  
Anionic Surfactant ◽  
Adsorption Mechanism ◽  
Coal Dust ◽  
Spreading Coefficient ◽  
Surfactant Solutions ◽  
Wetting Process ◽  
Adhesion Work ◽  
Dust Surface

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. The 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. This 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. The spreading coefficient can be used as an index to determine the wettability. The 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. The 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. The 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.

scholarly journals Preparation and Performance Analysis of a Spray Dust Suppressant for Coking Coal Dust

2020 ◽  
Author(s):  
Jiuhong Jiang ◽  
Pengfei Wang ◽  
Ye Pei ◽  
Ronghua Liu ◽  
Liming Liu ◽  
...  
Keyword(s):  
Reverse Osmosis ◽  
Moisture Absorption ◽  
Coal Dust ◽  
Sodium Dodecyl ◽  
Sodium Dodecyl Benzene Sulfonate ◽  
Coking Coal ◽  
Auxiliary Component ◽  
Orthogonal Experiments ◽  
Dodecyl Benzene Sulfonate ◽  
And Performance

Abstract Coking coal dust has strong hydrophobicity, and it is difficult to combine with droplets in the air and settle. In order to improve the ability of droplets to collect coking coal dusts, a spray dust suppressant for coking coal dusts was studied. Based on monomer optimization and compounding experiments, two types of surfactant monomers, fatty alcohol ether sodium sulfate (AES) and sodium dodecyl benzene sulfonate (SDBS), were selected as the surfactant components for the dust suppressant. Meanwhile, the surfactant monomers were combined with four inorganic salts and the reverse osmosis moisture absorption of each solution was measured. By combining the results of both reverse osmosis moisture absorption and the water retention experiments, CaCl 2 was selected as the inorganic salt auxiliary component for the dust suppressant. Finally, the best concentration combination of the three components were obtained using orthogonal experiments, i.e., AES (0.05%), SDBS (0.03%), and CaCl 2 (0.6%). The dust suppressant solution constituted by this scheme had a high moisture absorption and great performance.

scholarly journals Numerical simulation of the surfactants effect on the Taylor bubble in the PHP

2021 ◽  
Vol 2119 (1) ◽  
pp. 012173
Author(s):  
M V Alekseev ◽  
I S Vozhakov ◽  
V V Cheverda
Keyword(s):  
Numerical Simulation ◽  
Surface Tension ◽  
Liquid Film ◽  
Pure Water ◽  
Small Diameter ◽  
Surfactant Solution ◽  
Gas Bubble ◽  
Taylor Bubble ◽  
Aqueous Surfactant Solution

Abstract Numerical simulation of the motion of a Taylor gas bubble in a heated small-diameter tube is carried out. Two models are used to describe the dependence of surface tension on temperature. In the first model, the surface tension decreases with temperature, and in the second, it increases, which corresponds to pure water and an aqueous surfactant solution. It is shown that the derivative sign affects the thickness of the liquid film around the bubble.

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