Coal Dust Pollution Research Articles

Experimental and molecular dynamics simulation of the synergistic mechanism of short-chain fluorocarbon surfactant and electrolyte on inhibiting coal dust pollution

This paper investigated the synergistic mechanism of short-chain fluorocarbon surfactant and electrolyte on inhibiting coal dust pollution via the experimental and molecular dynamics simulations Findings illustrated that the synergistic application of short-chain fluorocarbon and electrolyte achieves better dust suppression performance when compares with the individual application of FS-50 and FS-3100, the maximum suppression rates for FS-50 and FS-3100 after the addition of electrolytes are 94.48 % and 93.94 %, respectively. The addition of electrolyte reduces the diffusion coefficient of suppressants, and its effect on FS-3100 is much higher than on FS-50. The maximum particle size achieved by FS-50 reaches 304–344 μm, while only 238–269 μm and 269–306 μm are acquired by FS-3100. The smaller negative potential and the larger difference in EPE indicate that the addition of NaCl promotes the adsorption of H2O molecules by surfactants. Compared to FS-3100, FS-50 has a lower negative potential and a larger EPE difference, suggesting that FS-50 exhibits stronger reactivity and better ability of absorb ion hydrates and H2O molecules, and hence has superior agglomeration effect. The addition of NaCl also promotes the generation of more sodium hydrate ions and hydrated chloride ions, which enhances the ability of FS-3100 to absorb H2O. Compares with FS-50, due to special curved spatial configuration and the synergistic effect with electrolytes, FS-3100 could restrict the desorption of large numbers of H2O molecules more effectively, and therefore exhibiting better wettability.

Inhibitory effect of calcium carbonate precipitation induced by Triton X-100 and microorganisms on coal dust

During underground tunnel construction, dust endangers the safety and health of workers. Microbially induced calcium carbonate precipitation (MICP) represents a novel green dust suppression technology for addressing coal dust pollution, capable of effectively mitigating coal dust pollution. Nevertheless, the concentration of urease will exert a certain influence on the performance of MICP to some extent. Therefore, how to improve the efficiency of urease activity on coal dust suppression is a popular research topic. In this study, based on MICP technology, the properties of microbial dust suppression materials were investigated through contact angle, surface tension, and unconfined compressive strength (UCS) tests in combination with molecular dynamics simulations, scanning electron microscopy, and X-ray diffraction using Bacillus megaterium and the nonionic surfactant Triton X-100. The results demonstrate that when the concentration of the bacterial solution is 20 % and the concentrations of urea and calcium chloride are 0.7 mol·L–1, the addition of 1 % Triton X-100 can increase the yield of calcium carbonate to 21.83 %, enhance the structural density of the gel, and increase the UCS by 15.63 %. The calcite and quartz formed on the coal dust surface improved its wettability with a contact angle of only 22°, showing an excellent dust-suppression effect. These research findings serve as a reference for enhancing the MICP dust suppression efficacy and have significant implications for the development and application of microbial dust-suppression agents. This dust suppression method has potential applications in quarries and underground environments.

Consolidation performance and mechanism of composite dust suppressant based on graft modification

AbstractTo solve the severe coal dust pollution and dust hazards in underground coal mines, this study utilized graft copolymerization modification technology and compound technology to develop a mining composite consolidation dust suppressant. On this basis, analysis of its consolidation wettability and dust suppression mechanism was conducted through characterization tests and molecular dynamics simulation methods. The results show that polyacrylamide (PAM) had been successfully grafted onto the soybean protein isolate (SPI) molecule, and form a SPI‐PAM complex. After the dust suppressant acted on the coal dust surface, it utilized its wealthy hydrophilic groups, for the adsorption of water molecules and the positive amide group for binding to produce a large area of agglomeration of coal dust particles at the interface, exhibiting good wetting and consolidation into a shell. At the same time, molecular dynamic simulation verified that the diffusivity of water molecules in the dust suppressant‐coal system was 0.30Å2/ps, decreased by 43.3%, and the interaction energy with coal molecules was −200.27 kcal/mol, absolute value increased by 41.35%, which made the dust suppressant molecules more easily adsorb and agglomerate on the surface, demonstrated an excellent solidification and dust suppression effect.

Study on the Water Absorption Characteristics of Anthracite Particles after Immersion in Water.

Reducing pollution caused by coal dust has always been a hot issue in the coal mining industry, and the water absorption of coal particles plays an important role in dust reduction. To study the relationship between different immersion time and the water absorption of coal particles, the substance content of coal particles after immersion was analyzed and water absorption characterization of coal particles was carried out by X-ray diffraction (XRD), water absorption calculations, and water absorption measurements. The results indicate that immersion can alter the material content of coal particles, leading to a decrease in the content of soluble mineral kaolinite, thereby affecting the wettability of coal particles. Notably, the longer the immersion time, the higher the water absorption rate of the particles, indicating a more significant water absorption effect. Furthermore, there is a negative correlation between particle sizes and water absorption of coal particles. The research results provide a theoretical reference for reducing coal dust pollution and improving the efficiency of dust suppression through spray.

Study on preparation and properties of mineral compound suppressant

To address the problem of coal mine dust pollution, the performance characterisation method was used to optimise the C3 dust suppressor. On this basis, two dust suppressants suitable for different climatic conditions were prepared by adding 8 groups of OP-10 and SDS surfactants with different concentrations, namely D5, which is suitable for dry areas and has excellent permeability, and E6, which is suitable for wet areas and has excellent resistance to rain erosion. The results show that compared with single dust suppressant, D5 with 0.5% OP-10 and E6 with 0.6% SDS have neutral PH, the rate of wind erosion is lower than 0.2% at 20 m/s, and the cured layer shell is well preserved with good wettability, adhesion and curability. Observed by scanning electron microscope (SEM), the coal dust particles bonded tightly after spraying D5 and E6, which could effectively improve the dust suppression efficiency.

Research on the Dust Transport Law in Large Mining Height Fully Mechanized Mining Face

The fully mechanized mining face with high mining height has always been a high-risk area for coal mine dust pollution. In order to further understand the spatiotemporal transport law of dust in the zoning of the high mining height fully mechanized mining face, the 122109 high mining height fully mechanized mining face of Caojiatan Coal Mine was taken as the research object. Numerical simulation method was used to simulate and analyze the dust transport situation of the 122109 fully mechanized mining machine drum single dust source, the hydraulic support moving frame single dust source, and the superposition of all dust sources in forward and backward wind cutting coal. The research results can guide the ventilation layout design in the early stage of the mine and the dust control in the comprehensive mining process, which is of great significance for the construction of safe and green mines.

Experimental and simulation studies on the improvement of coal dust pollution by an aqueous solution of sodium α-alkenylsulfonate and amino acid-based surfactants

The use of surfactants is crucial for the prevention and control of coal dust pollution in coal mining operation areas, yet there still exist many challenges in the control of coal dust pollution. In this paper, the green biomass-based amino acid surfactant sodium myristoyl glutamate (SMG) and the anionic surfactant sodium α-alkenyl sulfonate (AOS) were selected to investigate the improvement of coal dust wettability by single and binary solutions from the macroscopic and microscopic perspectives. Molecular simulations were used to reveal the microscopic mechanism of the wettability of coal dust by the different solutions. Experimental measurements showed that the contact angle of the AOS + SMG aqueous solution was as low as 13.8° on a coal surface. Coating the coal dust with the AOS + SMG solution reduced the surface tension by 12.02% compared to coating the coal with a single component solution. Additionally, the use of the binary AOS + SMG solution increased the hydrophilic group content in the coating by 11.77% compared to a single component solution, and the linkage between hydrophilic groups was enhanced, which pulls the water molecules to wet the coal dust. These research results should provide a new way to promote more environmentally friendly coal dust pollution control technology.

Research on the mechanism of coal wall fragmentation and dust production characteristics in the perspective of differentiated discrete elements

In order to efficiently and accurately control coal dust pollution in coal mining faces, this study addresses the insufficient research on the dust generation mechanism during cutting. Firstly, a similar experimental platform for simulating coal wall cutting with a drum cutter was used to investigate the changes in coal wall fragmentation and dust generation at drum speeds of 35 r/min, 50 r/min, 65 r/min, and 80 r/min. The experimental results revealed that the degree of coal wall fragmentation and dust generation increased with the increase in rotational speed, leading to a wider range of particle size distribution and an increase in the generation of fine dust particles. A 1:1 scale discrete element simulation of coal wall cutting with a drum cutter was conducted based on the experiments. The results indicated that, under the four rotational speeds, the cracks generated during coal wall fracture were predominantly tensile cracks, accounting for over 76% of the total crack count. The total number of cracks increased from 10,600 to 11,200, the number of free single particles increased from 2555 to 2728, and the fragmentation volume increased from 0.021607 to 0.023024 m3. The range and degree of coal wall fragmentation increased with the increase in drum speed.

Research on coal dust pollution prevention and control based on co-solvent association: Macro-micro experiments and molecular dynamics simulations

In order to better solve the environmental pollution caused by coal dust flying. In this paper, the improvement of wetting and hydrophilicity of coal dust by the binary association solution of surfactant and chelating agent tetrasodium iminodisuccinate (IDS) was studied from the perspective of experiment at the Microcosm–macrocosm analogy levels. To further explore the synergistic mechanism between chelating agents and surfactants, a coal surfactant/chelating agent water three-phase system was constructed using molecular dynamics simulation, and the motion trends of each molecule in different solution systems were analyzed in depth. The combined analysis revealed that sodium dodecylbenzenesulfonate had the best wetting performance when associated with IDS. It increases the surface pores and specific surface area of coal, and the surfactant is more widely adsorbed on the surface of coal dust. The proportion of oxygen-containing hydrophilic groups in coal dust increases, achieving improvement in wetting and hydrophilicity. Overcoming the problem of difficult wetting of coal dust has important practical significance for spray dust reduction and prevention of coal dust pollution.

Study on the influence of cross-section shape on the characteristics of wind flow field in heavy-daty railway tunnel

In order to reduce the coal dust pollution when the heavy train enters the tunnel and to ensure the safety of railroad operation, this paper adopts numerical simulation to study the characteristics of the wind flow field of the heavy train passing through different shapes of tunnels. The results show that the shape of the tunnel section has a significant effect on the piston wind characteristics of the train entering the tunnel. When the train passes through the tunnel, the value of the wind pressure and the gradient of the pressure on the surface of the carriages increase from horseshoe shape, high wall shape and high arch shape. The vortex structure generated at the entrance of the horseshoe tunnel is the smallest and the flow field is more stable, and the wind turbulence shows significant weakening effect; when the rear end of the car enters the tunnel, the range of the influence of the piston winds outside the tunnel is in order of smallest to largest for the horseshoe, high wall, and high arch tunnels; in the wake region, the central region of the strong vorticity zone in the horseshoe tunnel is more continuous, reducing the instability of the airflow in the tunnel. The results of this study are of great significance in understanding the characteristics of the wind flow field and the effect on dust generation when heavy trains pass through the tunnel.

Study of highly efficient control and dust removal system for double-tunnel boring processes in coal mines

To reduce coal dust pollution during double-tunnel boring processes in coal mines, an efficient control and dust removal system has been established and studied by combining theoretical analysis, experimental investigations, numerical simulations, and on-site measurements. The self-developed new spiral air curtain generator can quickly form multiple axial and radial dust control air curtains that cover the entire tunnel section. When combined with a wet-type dust removal fan, they form an efficient dust control and elimination system for double-tunnel boring in coal mines. The airflow and dust control effects of the highly efficient dust control and removal system, single press-in ventilation, and ventilation with dust removal fans were compared. The results show that with the proposed system, the dust concentrations in the boring tunnel and supporting tunnel can be controlled within 18 and 15 m distances from the working face, respectively. The dust control efficiency is increased by 82 % and 85 %, respectively. Hence, the dust concentrations in the coal mine are effectively reduced.

CFD-based simulation study of dust transport law and air age in tunnel under different ventilation methods.

To solve the problem of high-concentration dust pollution in a bored tunnel, we conducted a simulation study on the dust transport law and air age of the wind flow in a bored tunnel under different ventilation methods. Air age was innovatively introduced as an index for evaluating tunnel air quality. The results show that dust pollution is serious under conditions of press-in ventilation, which is unfavorable to personnel operations. Following the installation of an on-board dust-removal fan, an effective dust-control air curtain forms in the tunnel, and the high-concentration dust is essentially controlled within the range of Z = 13m from the working face. The dust concentration in the working area on the left side of the tunnel is CD < 200mg/m3, and the dust-control effect is obvious. At the same time, the air age on both sides of the tunnel is reduced by 35.5% following the use of the on-board dust-removal fan. Taking into account dust control by ventilation and dust removal by fan, spraying dust reduction measures are added, and we developed automated wind-mist synergistic wet high-frequency oscillation dust-capturing technology for tunnel boring. This could effectively improve the problem of high levels of coal dust pollution in tunnels.

Molecular dynamics simulation and experimental research on the influence of SiO2-H2O nanofluids on wettability of low-rank coal

Coal dust pollution is one of the problems needing urgent solution in global coal mining industry. Exploring environmental and efficient new wetting agents of coal dust has potential application value in the field. Taking the Wender model as the research object, Materials Studio molecular simulation software was used and physical experiments were conducted to study the influence mechanism of SiO2-H2O nanofluids on the wettability of low-rank coal (LRC). Results show that SiO2 nanoparticles (NPs) have a relatively high surface electrostatic potential, enabling strong binding capacity with LRC and water molecules. After SiO2 NPs are adsorbed on the LRC surface, more water molecules are adsorbed on the surface, which enlarges the interaction energy between solid-liquid molecules in the system. As the number of SiO2 NPs increases, the thickness of SiO2 NPs, thickness of coal-water interface, and mean square displacement (MSD) of water molecules all enlarge and the wettability of coal dust is enhanced. Compared with water, SiO2-H2O nanofluids have a lower surface tension and a smaller contact angle. The scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS) results further verify that the adsorption and aggregation of SiO2 NPs on the surface of coal dust are the essential cause for the enhanced wettability of coal dust. The molecular dynamics simulation results and experimental results are mutually verifiable, laying a theoretical basis for enhancing the wettability of coal dust using SiO2-H2O nanofluids.

Investigation on coal dust prevention by biomimetic mineralized dust suppressant with polyacrylic acid modifier

Coal dust prevention is crucial for the environment and the safety of coal miners. This study proposed a biomimetic mineralized dust suppressant (BMDS) with polyacrylic acid (PAA) modifier, based on calcium carbonate precipitation technology. The consolidation effect of BMDS on coal dust was evaluated through wind erosion resistance tests, unconfined compressive strength tests, and microscopic characterizations. The results show that the consolidation effect of the BMDS on coal dust heavily depends on the PAA concentration. When the PAA concentration is 4 g/L and the concentration of calcium chloride and sodium carbonate is 0.5 mol/L, the BMDS presents the best dust suppression effect and could realize the practical application requirements. The generated calcium carbonate is mainly calcite type, and the efficiency of cementing coal dust particles is the highest. Moreover, similar to bacteria in biological dust suppressants, it confirms that PAA could effectively modify the nucleation and growth of calcium carbonate, promote the adhesion of calcium carbonate to the surface of coal dust particles, and enable the generated calcium carbonate to effectively bond coal dust particles. Accordingly, the BMDS with PAA modifier can be effectively used in the prevention of secondary coal dust pollution.

Effect of welan gum and carbomer on foam and wetting properties of sodium alpha-olefin sulfonate for coal dust control

Using foam to reduce coal dust is one of the effective means to control coal dust pollution. In this work, the solution and foam properties of foaming agents consisting of sodium alpha-olefin sulfonate (AOS), welan gum (WL) and carbomer (CBM) were investigated, the wetting ability of the composite system on coal dust was compared, and the adsorption mechanism among AOS, WL and CBM was analyzed. The results show that with the increase of AOS concentration, the viscosity of AOS/WL solutions decreases gradually and then becomes stable, while the viscosity of AOS/CBM solutions displays an opposite trend. The addition of WL and CBM promotes foam production at low AOS concentrations but inhibits it at high concentrations. Both WL and CBM can improve the liquid volume and half-life time of foam drainage of AOS solutions. The WL molecules spontaneously form a zipper network structure, making the foam liquid film significantly thicker and slightly enlarging the bubble size. The addition of CBM can form a viscoelastic surface layer on the Plateau borders, making foam less permeable and delaying the bubble Ostwald ripening. The wetting time of coal dust is extended after adding WL and CBM. These results can provide theoretical guidance for the formula study of foaming agents for coal dust suppression.

How to optimize dust pollution control in opencast coal mines: Analysis of a joint social regulation model based on evolutionary game theory.

The carbon peaking and carbon neutrality goals drive innovation in pollution governance systems, unleashing the potential of social supervisory forces to achieve coordinated governance by multiple stakeholders. In order to improve dust pollution control in opencast coal mines, this study combines prospect theory with evolutionary game theory, analyzing the evolutionary game process of coordinated governance activities of coal mining enterprises, local regulators, and social camps in the management of dust pollution against the backdrop of national supervisions. The research indicates that the perceived value of dust pollution has a significant impact on the strategic choices of the three agents involved in the game. Coal mining enterprises tend to be risk averse, and by reducing the cost of dust pollution control and increasing the additional benefits of pollution control, it can promote pollution control behavior by coal mining enterprises. Local regulators are also risk averse, but not sensitive to risk benefits. Strengthening pollution subsidy incentives and environmental fines can help promote dust pollution control behavior by coal mining enterprises. However, increasing the strength of the rewards strategy is not conducive to local regulators' own regulatory responsibilities, and environmental fines have limited binding effects. The strategic choices of social camps' supervision have a restrictive effect on the strategic choices of coal mining enterprises and local regulators, promoting the evolution of equilibrium results in the direction of maximizing social benefits. When coal mining enterprises actively governance pollution, local regulators strictly regulated, and social camps do not monitor, the system reaches its optimal equilibrium state. The research results clarify the mechanism and specific effects of social supervision of opencast coal mine dust pollution control, guide the participation of the public in dust pollution control, and regulate the behavior strategies of coal mining enterprises and local regulators, providing the scientific basis for management.

Experimental and molecular dynamics simulation study of the ionic liquids’ chain-length on wetting of bituminous coal

Controlling coal dust pollution is confronted with numerous challenges in the demanding environment of deep mining. Chemical additives, imidazolium ionic liquids (ILs), have been considered an effective strategy to boost the hydrophilicity of coal and reduce dust emissions. This work conducted experiments with molecular dynamics (MD) simulation to study the wetting characteristics of ILs ([Emim][Cl], [Bmim][Cl], and [Hmim][Cl]) with different chain-length on coal. The static wettability tests results indicated that the wettability of ILs was improved as the chain-length increased, and the wettability on bituminous coal followed the rule of water<[Emim][Cl]<[Bmim][Cl]<[Hmim][Cl]. The dynamic dust suppression experiments in the roadway showed that the dust suppression efficiency of 2% [Hmim][Cl] reached 77.5%, 2.45 times that of water. The ESP and frontier orbital energy show that the chain-length increase can enhance the ILs activity. The MD results indicated that short-chain ionic liquid ([Emim][Cl]) tends to accumulate on the surface of coal molecules, whereas long-chain ionic liquid ([Hmim][Cl]) possesses the capability to permeate coal molecules and serves as a tunneling role between coal and water, thereby enhancing the hydrophilicity of bituminous coal. The research results could be used to determine and design ILs with excellent wetting performance for improving the coal dust suppression effect.

A Critical Study on the Management of Innovative Fugitive Coal Dust Pollution Control Practices for a Cleaner Industrial Environment

The entire world including India is inevitably dependent on coal-based energy. Thus, the consumption of coal happens to be maximum and most frequent in comparison to other minerals. But the consumption of coal gives rise to exploitation of coal in situ and thus increases the dust create from the same. Not only the coal dust is produced at the extraction site, the sources are multiple including the transportation, dumping sites etc. The very nature of coal in terms of self-combustion and self-heating aggravates the working environment in industries giving rise to hazards and health problems. The traditional practices of suppressing and controlling fugitive dust are having their own limitations and deficiencies. Therefore, the policymakers, the concerned authorities as well as the industry personnel are constantly searching for innovative approaches which can give better dividends. In this regard, many experiments and techniques proven to be successful to a substantial extent. However, the management of these techniques has to be multi-dimensional and multifaceted. This study conducted at different coal mines in Odisha has been an attempt to understand the deficiencies in the current practices and the benefits of adopting innovations in controlling the fugitive dust polluting air and other environmental elements. This also examines the managerial implications on practicing the innovations towards making a cleaner and industrial environment.

Synergistic effect of binary mixture of anionic nonionic surfactant on inhibiting coal dust pollution: Experiment and simulation

Coal dust is a pollutant particle generated during the process of coal development and utilization. It can cause damage to the surrounding environment and human health. In this paper, experimental and molecular dynamics simulations were used to select four surfactants: fatty alcohol polyoxyethylene ether sodium sulfate (AES), sodium dodecyl benzene sulfonate (SDBS), lauryl glucoside (APG-12), and fatty alcohol polyoxyethylene ether (AEO-9). The wettability and adsorption ability of a single surfactant and a combination of surfactants were studied at the macro and micro levels, Laying a foundation for the preparation of binary surfactants. The results show that the anionic nonionic binary composite aqueous solution of 0.07% SDBS and 0.05% AEO-9 can greatly increase the content of hydrophilic functional groups in coal molecules, and its hydrophobic groups can be firmly adsorbed on the pore size of coal dust, effectively solving the problem of poor hydrophilicity and difficult wetting of coal dust. In addition, on the basis of quantitative characterization of micromolecules and macro wetting test, research on foam characteristics has been added to further improve dust suppression efficiency and effectively control air pollution caused by coal mining and use.

Development and characterization of a high efficiency bio-based rhamnolipid compound dust suppressant for coal dust pollution control

Surfactants make a significant contribution to the suppression of coal dust fly in underground coal mines, but are hazardous to the environment and human health. It is therefore crucial to develop more environmentally friendly and efficient wetting agents using non-polluting eco-friendly surfactants. In this study, the wetting properties of the biosurfactant rhamnolipid were investigated and the rhamnolipid composite wetting agent (CS-A-S) was prepared by mixing design after preferring different surfactants by means of experiments and quantum mechanical simulations. The dust suppression properties were compared by means of infrared spectroscopy, scanning electron microscopy and molecular dynamics simulation. The results showed that the critical micelle concentration (CMC) of rhamnolipid was 0.04 wt% and the surface tension was 25.9 mN/m, which had the basis to become an underground dust suppressant; the surface tension of CS-A-S was reduced to 23.95 mN/m and the contact angle to coal dust was 25°; after spraying CS-A-S, the median particle size of coal dust reached 125.76 μm, an increase of 849.13%; the specific surface area was reduced to 2.24 m2/g, a decrease of 51.06%; the oxygen-containing groups on the coal surface increased by 55.87–246.7%, making it easier to form hydrogen bonds, the coal dust became more hydrophilic, and coal dust particles easily agglomerated into larger sizes and settled rapidly under gravity; the CS-A-S simulated system showed the greatest degree of water molecule penetration, with a minimum of 71 Å, and a water molecule diffusion coefficient of 1.06 Å2/ps, a decrease of 75%, and the interaction energy with coal molecules is 155.6 kcal/mol, an increase of 66.9%, making it easier for the dust suppressant molecules to form adsorption on the coal surface, showing a better dust suppression effect.