Dust Reduction Research Articles

Study on dust reduction characteristics and mechanism of softened mine water

ABSTRACT At present, the intensity of coal mining is increasing gradually, and the concentration of coal dust in roadways under integrated mining is high, making it difficult to control. As a result, the mechanism and technology of dust reduction remain one of the key points of efficient mining research. To study the influence of physical and chemical properties of mine water on dust reduction efficiency, this work used spray dust reduction experiment system to assess dust reduction efficacy of several solutions at 3～6MPa, and the differences in the dedusting characteristics and atomization characteristics of each group of each solution were analyzed. The result demonstrates that softened mine water’s surface tension and contact angle fall significantly, spray droplet size lowers, and fog dispersion becomes more symmetrical. When compared to before softening, the dust reduction efficiency of softened water (SW) is 72.52% for total dust and 69.74% for respiratory dust, considerably improving the working environment of underground coal miners and optimizing mining efficiency.

Synthesis and properties of wettability-increasing agent with multi-layer composite network structure for coal seam water injection

To improve the efficiency of water injection and reduce the amount of dust from the source. In this paper, a wettability-increasing agent with a multilayer composite network structure was prepared. The modified sodium carboxymethyl cellulose (CMC) and linear micelles were rearranged and combined by using the optimal ratio experiment. Through proton nuclear magnetic resonance spectroscopy, Fourier transform infrared spectroscopy, and X-ray diffraction analysis, the functional-group structure and crystallinity of the modified CMC were investigated. The elemental compositions and surfaces of C1 and C2 were examined via energy dispersive spectrometer, optical microscopy, and transmission electron microscopy. A performance test revealed that C2 had excellent temperature shear resistance, and its wettability was good, which was conducive to reduce the spreading of pulverized coal. By observing the coal in dry and wet states, the reason why C2 was suitable for dust reduction was determined. The changes in the functional groups of the soaked coal were analyzed, and the soaking effect of the C2 on the coal was determined. Finally, molecular dynamics simulation was used to verify that C2 played an effective role in promoting moisture wetting of coal.

Kinetics of Carbothermal Reduction of Electric Arc Furnace Dust from a Stainless Steel Plant

Kinetics of Carbothermal Reduction of Electric Arc Furnace Dust from a Stainless Steel Plant

NMR experiments on the migration characteristics of water in bedding-bearing low rank coal

Coal seam water injection is an effective technique for dust reduction in coal mines. Imbibition is an important means of water transport in coal seams and is influenced by coal bedding. The spatial distribution of water in the seepage process was obtained, and the spontaneous seepage characteristics and water transport mechanisms of coals containing different layered angles were revealed by NMR. Results show that the bedding mainly serves as the water flow channels in the imbibition. When the angle increases, the imbibition rate of adsorption pores and seepage pores in the early stage decreases. The imbibition is firstly transported to the top quickly along the bedding flow channel, 1.5h for 0° bedding coal sample, 24h for 90°, when the water reached its apex, the curve no longer changed and imbibition proceeded slowly. With the increase of bedding angle, the imbibition equilibrium time increased from 3h to 30h, up to 9 times more, the maximum imbibition rate decreases significantly, reduced from 5.64 g/h to 1.13 g/h, the flow resistance increases, and the remaining capillary force after equilibrium increases from 0.007 Pa to 5.24 Pa. When the capillary force cannot overcome the flow resistance, the imbibition reaches equilibrium.

Evaluation of Ecosystem Services Radiation Assessment of the National Ecological Sheltering Zone in China

Ecosystem services (ES) have been shrinking due to unreasonable development and utilization for a long time. There are many studies on ES, but the ecological information for policymakers is still complex and obscure. To address this critical omission, based on remote sensing data, combined with meteorological data, land use data, and administrative division data, using GIS spatial analysis technology and some ecological process models, we develop an ecosystem services radiation assessment framework (ESRAF) that can provide policymakers with concise and reliable ecological information. We illustrate the measurement of ESRAF through an application to specific regions of China’s national ecological sheltering zone (NESZ), showing that the approach can effectively identify the beneficiary areas (SBA) for sand-stabilization service, soil conservation service, and water conservation service, and the degree of sharing of ES of SBA. ES produced by ecosystems in a specific region not only generates huge benefits locally but also a large number of ES benefit surrounding regions through cross-regional transmission. Specifically, in 2015, the area benefiting from sand-stabilization service provided by the Ordos’s ecosystem is about 1.66×106 km2, the amount of dust reduction in SBA would reduce by 28,738.67×104 tons. The Loess Plateau Ecological Screen (LPES) provides critical soil conservation service, the SBA of LPES includes two parts: LPES and the Yellow River. The Northeast Forest Belt (NFB) provides vital water conservation services. The water conservation service beneficiary area is mainly located near the NFB, with 266 hydrological response units, covering an area of 8.982×104 km2. This study also showed that the transmission distance is inversely proportional to the radiation effect, that is, the benefit level decreases with the distance from SPA. According to the degree of sharing of ES of SBA, the proposed cross-regional differentiated ecological compensation scheme is helpful to promote regional sustainable development. At the same time, this study also shows that NESZ is of great significance for ensuring China’s ecological security.

Study on dust suppression performance of a new spray device during drilling and blasting construction in the metro tunnel

In order to solve the problems of excessive blasting dust concentration and portal pollution in a metro tunnel of a central urban area, a new spray device is discussed and its related parameters are studied in this paper. Through field sampling and an experimental spray dust settling platform, the particle size distribution characteristics of the tunnel blasting dust and the applicability of the nozzle are analysed. The tunnel and spray device are simulated by CFD software, and the variation laws of the droplet field concentration, velocity and particle diameter under different different incident angles, pressures and wind velocity are studied. The dust suppression performance of the new partition spray device is tested through field application. The results show that the droplet field generated by the spray device can effectively cover the whole section of the tunnel. At the same angle of incidence, the high concentration area first increases and then decreases in the direction away from the device, and the maximum concentration section gradually shifts away from the spray device. With the increase of the incident angle, the growth and attenuation trend of the high concentration region gradually flattens. The best incident angle for partitioning and dust reduction is 30°. When the nozzle pressure is set to 8 MPa, the parameters such as concentration, velocity and particle size distribution are the most appropriate. The effect of the air velocity at the air outlet on the characteristics of the droplet group generated by the device is not obvious. The field application shows that when the spray device is used, the dust reduction efficiency of respiratory dust and total dust at each measuring point is higher than 70 %. Compared with the original dust control measures, the average dust reduction efficiency is increased by 30 %, which can effectively improve the working environment of constructors in the tunnel and prevent the outward diffusion of dust.

Analysis on the application of intelligent system for automatic spray maintenance and dust suppression of super high-rise core tube

In recent years, with the rapid growth of China’s social economy and the rapid development of the construction industry, the number of high-rise and super-high-rise buildings in cities has increased significantly, providing great convenience for people’s lives. During the construction of super-high-rise buildings, a large amount of water resources are needed to maintain concrete, and the effective application of the intelligent system of automatic spray maintenance and dust reduction of super-high-rise core tube can not only effectively solve the problem that the outside maintenance of super-high-rise core tube shear wall is not in place, but also ensure the dust control effect on the construction site and realize the recycling of water resources. Based on this, the thesis will take automatic identification, mobile terminal control, rapid maintenance and dust reduction as the main ideas, and elaborate the dust reduction and maintenance automation of super-storey buildings in urban centers.

Research of the physico-chemical properties of hydrogel as a means of dust-explosion protection and dust reduction in coal mines

Research of the physico-chemical properties of hydrogel as a means of dust-explosion protection and dust reduction in coal mines

Field experimental study on comprehensive dust control technology in fully mechanized caving face of extra thick coal seam

In order to solve the dust treatment problem of the coal Permian extra thick coal seam mined by Tashan Coal Mine, the comprehensive dust treatment technology research was carried out with the 8106 comprehensive discharge face and 8210 comprehensive discharge face of Tashan Coal Mine as the geological background, and the four aspects of coal seam water injection process, determination of water injection parameters, inspection of water injection and dust reduction effect and application promotion prospects were analyzed and studied.

Exploration on Environmental Protection Supported by Big Data

With the rapid development of social economy, environmental problems are becoming increasingly severe, and human society is facing serious environmental pollution. Therefore, it is very necessary to apply big data technology to environmental protection work. Through the analysis of the application characteristics of big data technology, it can be seen that big data technology has made environmental protection work data-driven, and also further embodied the fundamental value of environmental protection. This article analyzed the changes in the environment by establishing environmental protection measures and applying big data, and calculated whether there was a significant improvement in the environment supported by big data technology. This article calculated the dust reduction data after the intervention of big data environmental protection measures in 2022 through experiments, which was significantly lower than the dust reduction data in 2019. Therefore, it has great advantages in environmental detection and other aspects.

Development of Clean Road System with Porous Pavement and Evaluation of Fine Dust Reduction Effect

Development of Clean Road System with Porous Pavement and Evaluation of Fine Dust Reduction Effect

Production of an odor-reducing, low-dust, clumping cat litter from soybean hulls and soybean hull biochar

Soybean hull biochar (SHB) was produced from soybean hulls (SH). Nine pelletized cat litter formulations at two different particle sizes (particle size 1 = between 0.84 and 2.00 mm; particle size 2 ≤ 0.84 mm) were produced from SHB and SH to determine water absorption (termed hydration capacity) and reduction of volatile thiols. One of these formulations from particle size 2 was chosen for additional testing. This formulation was combined with guar gum as a clumping agent and mineral oil as a dust reducer. The final formulation treated with simulated cat urine significantly reduced the population of three pathogenic bacteria over a three-day test period. Compared to four commercial biobased cat litters, this formulation was superior for odor and dust reduction while having hydration capacity and clumping ability equal to or better than the commercial litters.

Synthesis and properties of coal dust suppressant based on microalgae oil extraction

Dust suppression is an important method for improving the effect of wet dust removal in coal mines. With the aim of overcoming the challenges of weak interfacial performance and the poor dust suppression effect caused by traditional coal dust suppressants under hard water conditions, a new method for extracting microalgae oil to synthesize coal dust suppressants is proposed here. The optimized conditions of microalgae oil extraction were analyzed by single-factor experiments and a response surface methodology. A microalgae oil-based coal dust suppressant (MODS) was synthesized from the extracted microalgae oil and its structure was determined. Property and performance tests were carried out under hard water conditions and the influence of hardness conditions on the dust reduction effect of the MODS was analyzed. The results show that a solvent ratio of 2.04:1, a liquor-to-material ratio of 4:1 and an extraction time of 4 h were the optimal extraction conditions for the microalgae oil. The MODS is an amide dust suppressant with an average tolerance of calcium concentration of 1271.28 mg·L−1, which had good resistance to hard water. Under the hard water conditions, the surface tension of the MODS remained at 31.8–33 mN·m−1 when the temperature, pH and salinity changed greatly (temperature of ≤60 °C, pH of 2–13 and NaCl mass fraction of ≤43 %). The dynamic contact angles of sodium dodecyl benzene sulphonate (SDBS) and the MODS at 60 s were 26.78° and 13.41°, respectively, and the sinking time of coal dust in the MODS solution was significantly smaller than that in the SDBS solution at the same concentration. This implied that the MODS performed better with regards to wettability than the commonly used anionic surfactant SDBS. This study lays an important foundation for the development of green and hardwater-resistant coal dust suppressants.

New type of sawdust-based dust suppressant during tunnelling and underground space: Preparation, characterization and engineering application

In the process of underground tunnel construction, dust is the main killer endangering the safety and health of workers. New polymer dust suppressant materials have been proved to be an effective means to reduce dust concentration in restricted space. This study, based on the principle of waste utilization, is aimed at revealing a new degradable super absorbent dust suppressant (AA-SW-AMPS/ND), which is prepared by means of microwave-assisted chemical crosslinking with sawdust of China fir as the raw material. The micro morphology, reaction mechanism, water absorption and retention of AA-SW-AMPS/ND are studied through SEM, FTIR and swelling kinetic experiments. The product performance test shows that the dust suppression rate of AA-SW-AMPS/ND exceeds 95 %. The swelling rate in distilled water is more than 400 times, and the swelling rate in 1 % salt solution is maintained at about 100. After spraying AA-SW-AMPS/ND, the sample is in natural environment for 168 h, and the mass loss is less than 10 g; The synergy combustion performance time with coal sample is prolonged by about 50 s. By combining the new dust suppressant and its automatic adding device with the spray device, remarkable results have been achieved in the dust control of the fully mechanized face in the North seventh mining area of Tianchen coal mine. The average dust reduction rates of total dust and respirable dust have reached 90.07 % and 85.43 % respectively. The dust suppression and wetting mechanisms of AA-SW-AMPS/ND are explained by MS simulation, and the simulation results are consistent with the above experimental ones. This dust suppression method can potentially be applied in power plants, quarries, and other underground space environments.

Preferential binding effect of cocoa powder on fried donuts through the electrostatic coating method

SummaryDonuts are the snack food which are coated with powdered seasonings to increase flavour and shelf life. In this regard, electrostatic coating is being developed for efficient coating method and to overcome uneven coating and dust production. During electrostatic coating, charged powder particles produce even coating on target surface. Electrostatic coating of cocoa powder was carried out at high voltage (0–20 kV) and the results were compared to manually coated fried donuts. Cocoa powder particles had irregular polygonal and polyhedral shapes with an average particle diameter (18.12 ± 0.91 μm). The values of adhesion, dust reduction and transfer efficiency were higher at 15 kV and lower values at 0 kV. Coated sample at 15 kV showed the lowest change in weight loss (05.99%) during the storage. Due to an even coating of cocoa powder at 15 kV, donuts exhibited pleasant taste, uniform and dark brown colour. While, shelf life of coated donuts at 15 kV lasts up to 29 days as compared to other samples. It can be concluded from the results that the electrostatic coating of donuts with cocoa powder was best at 15 kV with higher transfer efficiency, adhesion and consumer acceptability.

Research for the recovery of Zn and Pb from electric arc furnace dust through vacuum carbothermal reduction

Isothermal kinetic methods were used to investigate reduction process in the Zn and Pb during the vacuum carbothermal reduction of electric arc furnace dust (EAFD). During the experiments, the volatilization ratios of Zn and Pb in EAFD increased with the increase of temperature and holding time, which was 96.29 % and 83.91 % for Zn and Pb respectively at a temperature of 1000 °C and holding time of 60 min. The main phase changes of Zn and Pb in the reduction process were ZnFe2O4 → ZnO → Zn and PbSO4 → PbO → Pb, and the generated Zn and Pb gases escaped and were collected via condensation. In the kinetic study, the volatilization of Zn was controlled by three-dimensional diffusion (Jander) with an apparent activation energy of 19.97 kJ/mol, whereas the volatilization of Pb was controlled by the interfacial chemical reaction with an apparent activation energy of 85.68 kJ/mol. The results show that higher purity of valuable metals Zn and Pb could be obtained, laying a theoretical foundation for the treatment of EAFD pollution.

Synthesis of Micro-Electrolysis Composite Materials from Blast Furnace Dust and Application into Organic Pollutant Degradation.

A micro-electrolysis material (MEM) was successfully prepared from carbothermal reduction of blast furnace dust (BFD) and coke as raw materials in a nitrogen atmosphere. The MEM prepared from BFD had strong ability in removing methyl orange, methylene blue, and rose bengal (the removal rates of methyl orange and methylene blue were close to 100%). X-ray diffraction showed that the iron mineral in BFD was ferric oxide, which was converted to zero-valent iron after being reduced by calcination. Scanning electron microscopy showed that nano-scale zero-valent iron particles were formed in the MEM. In short, the MEM prepared from BFD can effectively degrade organic pollutants.

Analysis of Dust Emission Characteristics of Peanut Whole-Feed Harvesting Based on Total Amount Collection Method

In view of the lack of a total amount collection method of dust emitted from a peanut whole-feed harvester and the unknown characteristic parameters of dust emission, a total amount dust collection method based on the combined action of centrifugation and filtration was proposed. The structural parameters of a total amount dust collection device were designed through theoretical analysis. On this basis, the production of a total amount dust collection device and a total amount dust collection test of the peanut whole-feed harvester were completed. The test showed that the total amount dust collection device could meet the needs of dust emission characteristics research. After analyzing the collected dust, it was found that the emitted particles were a mixture of soil particles and fiber particles. When the engine speed of the harvester was increased from 1600 rpm to 2400 rpm, the total emission rate increased from 3.36% to 4.28%, and the particulate emission rate increased from 1.44% to 2.63%; it also caused 4.29~4.98% of seedling blowing loss. The emission proportion of soil particles was reduced from 58.93% to 44.25%, and the emission proportion of fiber particles was increased from 41.07% to 55.75%. Among the emitted particles, the particle size peak of soil particles was concentrated at 22.9~30.2 μm; the particle size peak of fiber particles was concentrated at 478.6~631.0 μm. The research method and results can provide a reference for the optimization of dust reduction and emission reduction of peanut whole-feed harvesters and similar crop harvesters.

A Machine Learning-Based Energy Management Agent for Fine Dust Concentration Control in Railway Stations

This study developed a reinforcement learning-based energy management agent that controls the fine dust concentration by controlling facilities such as blowers and air conditioners to efficiently manage the fine dust concentration in the station. To this end, we formulated an optimization problem based on the Markov decision-making process and developed a model for predicting the concentration of fine dust in the station by training an artificial neural network (ANN) based on supervised learning to develop the transfer function. In addition to the prediction model, the optimal policy for controlling the blower and air conditioner according to the current state was obtained based on the ANN to which the Deep Q-Network (DQN) algorithm was applied. In the case study, it is confirmed that the ANN and DQN of the predictive model were trained based on the actual data of Nam-Gwangju Station to converge to the optimal policy. The comparison between the proposed method and conventional method shows that the proposed method can use less power consumption but achieved better performance on reducing fine dust concentration than the conventional method. In addition, by increasing the value of the ratio that represents the compensation due to the fine dust reduction, the learned agent achieved more reduction on the fine dust concentration by increasing the power consumption of the blower and air conditioner.

Molecular mechanism of the effect of benzene ring structure in nonionic surfactants on the wettability of anthracite

Reducing coal dust is critical for environmental protection and energy efficiency, however anthracite has a high degree of coalification, high hydrophobicity, resulting in a poor dust removal effect. The addition of surfactants to water can improve the wetting of coal dust, resulting in a more effective dust reduction effect. In this investigation, Polyethylene glycol octyl phenyl ether (Triton X-100) and The lauryl polyoxyethylene ethers (C12(EO)9) were chosen as research subjects. Contact angle experience, Fourier Transform infrared spectroscopy experience (FTIR), and X-ray Photoelectron Spectroscopy experience (XPS) were used to compare the ability of two surfactants to improve the wettability of anthracite from a macro perspective. Molecular dynamics (MD) simulation was used to explain macroscopic experimental phenomena from a microscopic perspective. Due to the presence of the benzene ring structure in the hydrophobic group, the surface of anthracite following Triton X-100 adsorption is more hydrophilic. The network structure of Triton X-100 molecules on the surface of anthracite is loose owing to the presence of the benzene ring, which facilitates water molecule penetration.