An Experimental Study on Wetting of Coal Dust by Surfactant Solution

Abstract

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.

Study on Surface Activity of Inorganic Salts on [C12MIm]Cl and Wetting Characteristics of Compound Modified Bituminous Coal

“…7−9 The U.S. Bureau of Mines and the European Union stipulate that the maximum concentration of dust in mining operations is 50 mg per cubic meter and 0 mg per cubic meter. 10,11 Current dust control technologies for working surfaces includes water injection dust removal, ventilation to reduce dust, air curtains to isolate dust, etc., in which coal seam water injection is widely used. 12−14 However, coal is highly hydrophobic, and water has a very poor wetting effect on coal, resulting in a slow penetration rate and low dust reduction efficiency.…”

Wettability Characteristics of Low-Rank Coals Under the Coupling Effect of High Mineralization and Surfactants

“…Experimental studies aimed at improving the wettability of coal seams and gas extraction efficiency concentrated on water injection and gas injection displacement. Research on water injection focused on the use of surfactants. − Surfactants are the main wetting agents in improving wettability, and surface tension is a key parameter for their effectiveness. − Jiang et al found that OP-10 surfactant solutions had the best effect on improving coal wettability based on surface tension and contact angle measurements of different wetting agents. , Several studies have explored the effect of wetting agents in different proportions or combined with other materials to improve the wettability of coal seams. ,− For instance, Zou et al added water-based SiO 2 nanofluids to the wetting agent solution and proposed a water injection method for coal seam improvement. , Molecular simulation software has been employed by some scholars to investigate the mechanism of surfactant effect on enhancing coal seam wettability. ,, In addition, the COMSOL simulation software was used to develop a coupled damage model during water injection to increase gas extraction rates. , Studies on gas injection displacement for improving gas extraction rates can be categorized into two types: using gases with strong adsorption capacity or gases that can break the dynamic balance of coal seam gas. − CO 2 -enhanced coalbed methane (CO 2 -ECBM) technology is essential to ensure energy security and achieve the “dual carbon” goal. This technology is crucial for achieving the low-carbon, clean, and efficient utilization of coal-based fossil energy.…”

Experimental and Molecular Dynamics Simulation Study for Preferring Coal Dust Wetting Agents

“…The wettability of coal dust was determined by the contact angle parameter, and the wettability mechanism of the dust suppressant to coal dust was revealed by Fourier-transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy instruments. Jiang et al 18 studied the effects of surfactant type, mass fraction, coal deterioration degree, particle size, and additives on the wettability of coal dust by contact angle parameters, and the optimal surfactant was selected. The above research studies only determine the wettability of different surfactants to coal dust by the contact angle parameter, and the surface tension of the wetting agent also affects the wettability of coal dust.…”