Dust Reduction Research Articles

Preventive maintenance and silica exposure limits integrated in the production planning of a granite processing unit

PurposeThis paper studies the integration of production and maintenance planning for an unreliable production system subject to gradual deterioration. The goal of this planning is to optimize production and maintenance while reducing workers' exposure to silica dust. The objective will therefore be to offer manufacturers a production strategy that minimizes the total cost of production while considering the health of employees.Design/methodology/approachAdequate prevention methods are determined and integrated into the granite transformation production system, which evolves in a stochastic environment. With the failure rate of the dust reduction unit being a function of its degradation state, the authors solve the optimization problem using stochastic dynamic programming in the context of nonhomogeneous Markov chain.FindingsThe resulting planning strategy shows that one can manage stock optimally while ensuring a healthy environment for workers. It ensures that crystalline silica prevention equipment is available and effective and defines the production rate according to a critical threshold, which is a function of the age of the dust reduction unit.Research limitations/implicationsThis article illustrates that it is possible to integrate silica dust reduction measures into production planning while remaining optimal and ensuring the health of operators. In the present study, the machined granite was assumed to be a natural granite, and production takes place in a closed environment.Originality/valueThe originality of this work lies in its development of an optimal joint production and maintenance strategy, which considers limits of exposure to crystalline silica. An optimal production and maintenance control policy considering employees' health is therefore proposed.

Numerical Modelling of Blasting Dust Concentration and Particle Size Distribution during Tunnel Construction by Drilling and Blasting

In order to reduce the blasting dust concentration in the tunnel during the drilling and blasting, accelerate the tunnel excavation process, and improve the working environment for the construction workers, a three-dimensional geometric model of dust transport was established based on the gas-solid two-phase flow model using the DesginModeler software, and the discrete phase model (DPM) in the FLUENT software was used to simulate the variation of dust concentration and the distribution of dust particle size at different locations along the tunnel route within 1200 s after tunnel blasting. The results showed that the concentration of blasting dust gradually decreased over time, with the fastest decrease in the range of 2 s to 120 s, and after 900 s, the dust concentration stabilized. The overall spatial distribution of the dust concentration showed a trend of decreasing from the palm face to the tunnel entrance and from the bottom plate to the upper part. The distribution pattern of dust with different particle sizes was not the same along the length of the tunnel. The large particles settled in the area of 25 m from the palm face under the action of gravity. With the increases of distance, the mass flow rate decreased, and the dust particle size became smaller, but the proportion of small particles gradually increased, while the R-R distribution index increased. The results in this study were confirmed to be reliable by comparing the measured data to provide guidance for the dust reduction technology in tunnel blasting, so as to quickly remove the dust generated during the blasting process and improve the engineering construction efficiency.

Evaluation of electrostatic powder coating method to prolong the shelf life of cheese slices.

Electrostatic coating is being developed as an attractive alternative to overcome the problems encountered during conventional coating which includes non-uniform coating, dust generation, high energy and time consuming, equipment cleaning, and operating expenses. In this method, powder particles are charged by passing through an ion-rich region, which repel each other to produce an evenly distributed coating. This results in a uniform distribution of powder on target surface. In this study, the electrostatic coating of black pepper powder was applied by varying the applied voltage (0-20 kV), at a conveyor belt speed of 10 m/s and compared with manually coated cheese slices. The values of transfer efficiency (52.7%-87.0%), dust reduction (76.2%-85.8%), and adhesion (20.8%-85.3%) were higher for electrostatic coatings. The weight losses were lower (0.19%) at 15 kV as compared to 20 kV (0.67%). The total plate count of cheese slice coated at 20 kV was significantly higher (p<0.05), whereas at 15 kV it was lower than all other treatments. The shelf life of coated cheese slices at 15 kV lasted up to 1 month due to better coating compared to other treatments. From the results, it can be concluded that electrostatic coating of cheese slice with black pepper is best at 15 kV along with higher transfer efficiency and dust reduction. PRACTICAL APPLICATION: Electrostatic powder coating of cheese resulted in higher transfer efficiency and reduction in dust production. later one has reduce the coating material requirement, thereby, reducing the processing cost. Moreover, dust reduction will reduce the burden of cleaning cost of environment and enhance worker health.

Dynamic dispersion and high-rise release of coal dust in the working surface of a large-scale mine and application of a new wet dust reduction technology

To determine the dynamic dispersion process of coal dust in a working surface characterized by a large mining height, as well as the formation time and the dispersion range of a heavy pollution area of coal dust in the same working surface, we restored the field production conditions and performed a simulation analysis by using the FLUENT software. The results of our analyses showed that: within 30–120 m from the lower wind side of the hydraulic support's advancing point, the minimum airflow speeds along the machine passage and the sidewalk were 0.41 m/s and 0.24 m/s, respectively. At T = 60 s, coal dust initially formed at ⁓ 40 m from the downwind side of the front drum and the average mass concentration in the high-concentration coal dust contaminated area was 1840 mg/m3. At T = 600 s, coal dust diffusion achieved a dynamic balance, at 60 m from the downwind side of the front drum; in this case, the average coal dust mass concentration in the high-concentration coal dust dispersion area reached 1470 mg/m3. A new wet dust reduction technology was installed at the starting location of a highly polluted area: the average coal dust reduction rates were 73% and 82%. These results confirm the efficiency of the proposed technology in reducing the spread of coal dust pollution and in avoiding the problem of high coal dust concentration in large mining environments.

Development of a methodology for optimizing the component composition of the charge for the processing of gts of steelmaking, providing the efficiency of useful components extraction

The article deals with the recycling issues of electric steelmaking dusts by thermodynamic extraction of iron, zinc and lead in order to reduce the impact on the environment and increase the industry resource base. The purpose of the research was to determine the influence of the quantitative content of low-calorie and high-calorie carbon on the processes of zinc oxide reduction in gas purification dust and its further sublimation using a vacuum in a closed system of a resistance heating furnace. Determined the dependence of the zinc extraction degree and the increase of iron oxides in the samples studied.

Numerical Simulation Study on Dust Suppression Mechanism of Burning Rock Blasting in Open-Pit Mine

In an open-pit mine in Xinjiang, part of the stripped area is covered by burnt rock. Due to the low strength and fragility of burnt rock, dust is more easily generated during blasting. Taking the mining area as the research background, the mechanical property parameters of burnt rock were tested, and the blasting parameter design of on-site operation was understood. The blasting numerical simulation of burnt rock step was carried out by using a numerical simulation software (LS-DYNA). From the angle of stress on rock, the stress cloud and stress curve of numerical simulation are analyzed, and it is concluded that the fundamental reason for the large dust production in blasting operation is that the burnt rock is crushed excessively after the action of explosion wave, and the explosive energy is too large, which is converted into kinetic energy to drive the dust to escape. In order to improve the utilization rate of explosives and reduce the output of blasting dust, the original blasting parameters were optimized as 8-m hole spacing, 6.5-m row spacing, 0.21-kg/m³ unit explosive consumption, 1-m interval charge, and 55-ms short-delay blasting through numerical simulation and orthogonal experiment. In the mining area, the measures of dustproof and dust reduction by blasting protection blanket and dust absorption cotton are adopted. Combined with the optimized blasting parameters, the field test proves that the dust removal efficiency is up to 82.4%.

Effects of Restaurant Owners’ Perceptions of Fine Dust onNegativeEmotion and Fine Dust Reduction Behavioral Intentions: Moderating Effects of Operational Types

본 연구는 우리나라 외식업체 경영자들의 미세먼지 위험을 줄이기 위한 행동의도를 파악하기 위해 미세먼지에 대한 관여도, 심리적 거리감, 부정적 감정 그리고 미세먼지 저감행동의도의 관계에 대하여 분석하였다. 또한, 가정된 관계에서 레스토랑의 운영형태에 따른 조절효과도 검증하였다. 본 연구를 수행하기 위해 전국의 외식업체를 운영하고 있는 경영자들을 대상으로 설문조사를 하였으며, 365개의 표본을 바탕으로 분석하였다. 분석한 결과, 외식 경영자의 미세먼지에 대한 관여도와 심리적 거리감은 부정적인 감정에 유의한 정의 영향을 미친다는 것을 밝혀냈으며, 부정적 감정도 미세먼지 발생을 줄이기 위한 저감행동의도에도 유의한 영향을 미친다는 것을 알 수 있었다. 또한, 레스토랑의 운영형태(프랜차이즈 vs 독립 레스토랑)에 따른 조절효과는 미세먼지에 대한 관여도와 부정적 감정과의 관계와 미세먼지에 대한 부정적 감정과 저감행동의도의 관계에서 유의한 것으로 나타났다. 이러한 연구 결과를 바탕으로 외식업체 경영자들이 미세먼지 위험에 대하여 인지하고 미세먼지 발생을 줄이기 위한 운영 방안에 대해 수립할 수 있으며, 효율적으로 미세먼지를 관리할 수 있는 대책의 필요성에 대한 시사점들을 제공할 수 있을 것이다.

Experimental and molecular dynamics simulation research on compound dust suppressant based on locust bean gum

To solve the problem of coal dust pollution, this paper used experiments and molecular dynamics simulations to develop a new composite dust suppressant with locust bean gum as the binder, fatty alcohol polyoxyethylene ether as the wetting agent, and glycerol as the water-retaining agent. Through a single factor analysis of the effects of each material, the appropriate concentrations of each were selected for an orthogonal experiment. The best composition of dust suppressant was obtained from an anti-wind erosion experiment. Then, scanning electron microscopy and energy-dispersive X-ray spectroscopy were performed on a coal sample sprayed with dust suppressant to observe that the dust suppressant had good adsorption on and binding to low-rank coal. Finally, an on-site experiment was conducted on the developed composite dust suppressant. The dust reduction rate reached 92.3%. Materials Studio software was used to simulate the interaction between dust suppressants and coal dust, with pure water as a control group for comparison. By analyzing the electrostatic potential of the dust suppressant and low-rank coal molecules, as well as the relative concentration distribution curves of both molecules, the water molecule mobility, and the heat of adsorption, the micro-action between dust suppressants and coal could be understood.

Effect of Basicity on Direct Reduction and Self-pulverization of Stainless Steel Dust

Effect of Basicity on Direct Reduction and Self-pulverization of Stainless Steel Dust

Thermodynamic Analysis of Electric Arc Furnace Dust Reduction by Volatile Matter of Non-Coking Coal

Thermodynamic Analysis of Electric Arc Furnace Dust Reduction by Volatile Matter of Non-Coking Coal

Numerical simulation and an experimental test for the pneumatic spray dust reduction of the belt transshipment system

In order to address the problem of dust pollution at the transfer point of the coal transportation system, this paper carries out a numerical simulation on the dust diffusion law of the coal transportation system. The simulation results show that the dust concentration at the three openings in the transshipment point is the highest, and the farther away from the transshipment point, the lower the dust concentration. Depending on the simulation results, a pneumatic spray dust reduction scheme can be proposed by performing a field experiment. Based on the controlling variable experiments and existing studies, the parameters of pneumatic spray can be stated in the following way: the flowing rate should be laid out at 0.7 l/min, with its air velocity being 25 m/s and the working pressure being 0.6 MPa. The entire spray scheme can be verified through the computer simulation process. Thus, it can be calculated and determined that the spray scheme should be installed with four nozzles at the anterior end of the lower belt guide trough, with one nozzle at the back end and two nozzles at the upper belt feeding point. Eventually, the scheme has to be validated by the field experiments. Thus, the consequences of the on-spot experiment and test show that the scheme we have suggested is in a position to reduce the dust concentration effectively in the entire area of the transshipment point, bringing about the dust reduction rate over 90%.

The role of economic development on the effectiveness of industrial pollution reduction policy in Chinese cities

The societal impact of industrial pollution produced by economic activities is a global concern. This paper presents a causal analytic framework to evaluate the effectiveness of government policy on the reduction of industrial pollutants in 284 Chinese cities between 2005 and 2016. This study reports on the interaction between industrial pollution reduction and the level of regional economic development from four dimensions by using analysis of variance (ANOVA),multivariate analysis of variance (MANOVA) and a bootstrap autoregressive-distributed lag (ARDL) test. The results indicate that city government policies, economic power, the influence of megacities, and the geographical region of the cities have significant effects on industrial pollution, in particular, sulfur dioxide (SO2) emission reduction and dust reduction. After taking account of the interaction effect of city government policies and the other three factors, it was found that economic power is the only factor to have a significant interaction with city government policies on industrial pollution reduction. The ARDL test found long-term causality among industrial pollution reduction, fixed assets investment, and GDP per-capita in city, urban agglomeration, and regional levels. This study sheds new light on the relationship between regional economic development and the development of sustainable societies.

Effect of Reduction Parameters on the Size and Morphology of the Metallic Particles in Carbothermally Reduced Stainless Steel Dust

In this work, we explored the possibility of producing fine near-spherical metallic particles via carbothermal reduction of stainless steel dust. For this purpose, we carbothermally reduced stainless steel dust under different reduction temperatures and times by using a vertical tube furnace, with special focus on the size and morphology of the metallic particles. High temperature and long reduction time favored stainless steel dust reduction. The reduction was almost completed after 10 min at 1300 °C. The metallic particles obtained at 1000 °C and 1200 °C were very irregular. At 1300 °C, however, more than half (> 55.0%) of the metallic particles became near-spherical (aspect ratio < 1.5), especially when extending the reduction time to 30 min. Long reaction time greatly promoted the growth of the metallic particles. Both primary M7C3 carbide and residual oxides contribute the irregularity of the metallic particles. Chemical composition of residual oxides affected the size of the metallic particles. The metallic particles surrounded by SiO2-rich oxides were much larger than the particles surrounded by MgO-rich oxides.Graphical Abstract

A multi-indicator orthogonal investigation into the dust suppression effect of a shearer-mounted negative-pressure spraying device

The actual production situation of a coal face with a large mining height of 6.5 m was taken as the research object, and factors investigated included spray pressure (P), nozzle retraction distance (L), and nozzle quantity (N) as the key research factors to solve the problem of dust pollution. Our analysis demonstrated the order of importance of the influence on the size of the droplets is P > L = N; the order of importance of the influence on the number of droplets is P > N > L; and the order of importance of the influence on the strength of the negative pressure is P > N > L. It was concluded through comprehensive analysis that when P = 8 MPa, L = 94 mm, and N = 6, the dust suppression efficiency of the device could reach more than 86%. The optimal spray dust reduction parameters were obtained by combining numerical simulation technology with an orthogonal experiment, and dust concentration was effectively reduced.

Effect of imidazolium-based ionic liquids on the pore wetting characteristics and mechanical properties of coal

Exploring the pore wetting pattern of the imidazolium-based ionic liquids-water system is necessary to understand the dust reduction effect from the source of the coal seam and its influence on the mechanical properties. Low-field nuclear magnetic resonance (LF-NMR) is used to analyze the wetting effect of different concentrations and types of ionic liquids-water systems on different pore sizes from the pore size distribution. Uniaxial compression mechanics experiments are used to investigate the changes in mechanical properties of the coal after wetting, and a scanning electron microscope is used to observe the differences in surface morphology of the coal after treatment with aqueous solutions of ionic liquids. The results show that the wetting effect of aqueous solutions of different concentrations of imidazolium-based ionic liquids is different for micropores, mesopores and macropores compared to pure aqueous solutions. At the same time, the pore wetting of the coal samples by the aqueous solution of the imidazolium-based ionic liquids altered their mechanical properties, with a minimum strength of 8.57 MPa for the 2 wt% [Bmim][BF4] treated coal samples. Analysis of microscopic morphology shows that the surface minerals of coal samples treated with imidazolium-based ionic liquids are dissolved, forming linked fissures or pores between minerals, which positively affect pore wetting. The revelation of the pore wetting properties of ionic liquids systems on coal is conducive to enriching the theory of coal seam dust control and is of practical significance for efficient dust reduction in mines.

Decreasing Dust Over the Middle East Partly Caused by Irrigation Expansion

AbstractThe importance of the effects of anthropogenic activities on modulating the global dust cycle has been increasingly recognized. Over the Middle East, we find in observations that there has been a significant decrease in dust optical depth from 2007 to 2019 during which global irrigated areas especially in the Middle East and South Asia have rapidly expanded. Whether irrigation expansion contributes to the decrease of dust in the Middle East is investigated based on observations/reanalyses and global climate model simulations with and without irrigation. Results show that irrigation over the northeast Middle East and Pakistan supplements water to the soil. By increasing local evaporation and moisture advection, irrigation enhances precipitation over the whole Middle East and the northwest Indian subcontinent. As a result, dust wet deposition by precipitation is elevated. Owing to irrigation‐induced land surface cooling, surface wind speed decreases as the planetary boundary layer becomes stable. Along with increased soil moisture, reduced surface wind speed suppresses local dust emissions. Enhanced dust wet deposition and suppressed dust emissions cause atmospheric dust reduction over the Middle East. Vegetation greening in the Middle East as the climate warms has no contribution because there is no obvious trend found in observations.

유리산업의 대기환경 특성에 관한 연구

In this study, we investigated air pollutants in the glass industry, and converted the fuel of the melting furnace used in the glass industry for the first time in Korea from B-C Oil to LNG. By investigating the saving effect and changes in air pollutants NOx, SOx, and Dust, the following conclusions could be drawn. Switching the melting furnace fuel (BC Oil → LNG) to minimize the environmental impact of the glass industry resulted in a 65 % reduction in SOx, an 18 % reduction in Dust, and a 43 % increase in NOx. However, when the temperature of the melting furnace stabilizes, it will decrease. In terms of cost, it was possible to reduce the basic charge by about 200 million/year by reducing NOx, SOx, and dust. It was possible to reduce the NaOH usage by more than 80 %, saving about 100 million won/year of drug costs. EP dust generated from the electrostatic precipitator was able to reduce waste treatment cost by KRW 40 million/year by reducing NaOH usage by 80 % and EP dust by 65 %. Greenhouse gas emissions were reduced by 28,000 [tCO₂/year], reducing about 800 million won based on 30,000 won in emission credits. This is to suggest an improvement plan that can be an effective and sustainable response to the change of pollutants according to the change of fuel used and the reduction goal of the 「Special Act on Air Environment Improvement in Air Management Areas」 to be enforced in 2020.

친환경 DPF Cleaning을 통한 노후 경유자동차의 배기가스 및 미세먼지 저감방안 연구

Despite the government’s policies to reduce fine dust in the transportation sector, such as regulations on the operation of emission-grade 5 diesel vehicles, subsidies for scraping old diesel vehicles, and Diesel particulate filter(DPF) installation, it does not contribute much to the reduction of fine dust. This study aims to contribute to the government’s policy to reduce fine dust in the transportation sector by identifying the efficiency of reducing exhaust gas and fine dust of diesel vehicles through DPF Cleaning and presenting economic effects through benefit cost analysis. Comparing before and after DPF Cleaning, the reduction rate of PM₁₀ and PM_2.5 after DPF Cleaning was high, and according to the economic analysis results of the DPF Cleaning project, the current value of the cost(NPV) was KRW 40,279.6 million, indicating that the B/C(Benefit/Cost) was 2.7, As it is analyzed that it is worth 70.152 billion won in net present value, it is considered that there is a need to legislate the government''s subsidy support policy for Cleaning of DPF and periodic Cleaning.

Analysis of the Factors Affecting Fine Dust Concentration Before and After COVID-19

This study conducted a comparative analysis of the factors affecting the concentration of fine dust before and after COVID-19. Of these, the dominant factor was CO, and the influence between variables increased even after COVID-19. In the case of PM10, the influence of wind direction and wind speed variables decreased, which is thought to be due to the reduction of westerly-based foreign air pollutants following China’s containment policy. Comparative analysis by season showed that the influence of temperature and humidity was higher in winter. In spring, the influence of wind direction and speed decreased with changes in the westerly wind and the influence of China’s containment policy. In summer and autumn, when the concentration of fine dust is relatively low, the influence of CO after COVID-19 was rather high, indicating that continuous CO management is necessary. Considering the relationship between these air pollutants and the meteorological environment, it is judged that fine dust reduction measures should be implemented.

Research on Dust Migration Law and Dust Reduction Efficiency in the Operation Process of Tunnel Boring Machine

At present, most dust reduction methods do not consider the difference of dust particle diameter distribution along the tunnel and the applicability of droplet group under different parameters. In order to improve the dust reduction efficiency of each section, the particle size analyzer was used to analyze the dust samples of each section along the tunnel, and the migration law of dust of each particle diameter during the construction of Tunnel Boring Machine (TBM) was studied. The dust falling efficiency of droplets with different particle diameter under different sets of parameters was determined by the experimental platform built by ourselves. Research indicates: along the axis of tunnel, the farther away from the face of the tunnel, the higher the peak volume frequency of dust, and the distribution range of dust gradually narrowed to the direction of small particle diameter. The settling distance of dust with different particle diameter is quite different, and the content of small particle diameter dust shows an upward trend as a whole. The reduction efficiency of dust first increases and then decreases with the particle diameter, and there is particle diameter of the optimum dust reduction efficiency under the action of the same droplet group. The calculation formula of the air and water flow of the air-water nozzle and the particle diameter of the optimum dust reduction efficiency are put forward. This research can provide basis and guidance for multistage dust reduction and nozzle parameter setting in different sections of the tunnel.