Dust Collection Efficiency Research Articles

Evaluation of Saw Blade Designs on Controlling Dust from Cutting Fiber-cement

ABSTRACT Fiber-cement can contain as much as 50% crystalline silica and cutting this material has shown to cause excessive exposures to respirable crystalline silica. We conducted this study to evaluate different saw blades for cutting fiber-cement siding, aiming at identifying blade design features that lead to lower dust release. Through laboratory evaluations of 22 saw blades, the releasing rate of respirable dust, i.e., GAPS, was analyzed and compared with and without engineering control measures. Two on-tool passive control measures were specifically evaluated. First, a dust-collecting box with a capped exhaust port was attached to the circular saw. Second, the dust-collecting box was connected to a passive dust collector, which includes a cyclone dust collector and an air filter. Both control measures help collect a portion of the dust with the aid of the induced airflow from the fast-spinning blade. The GAPS generally increased with the number of teeth and the kerf width of the blades. However, the number of teeth seems to have a reduced effect on GAPS for the conditions with the two control measures, possibly due to a higher airflow rate induced by more blade teeth, which results in more dust captured by the dust collectors. The 4-tooth Hitachi blade had the lowest GAPS under all three testing conditions, likely due to fewer teeth, thinner kerf, and its specific design characteristics of a “smooth” gullet optimizing induced airflow and dust transporting into the dust collectors. The control measure with the added passive dust collector provided a dust collection efficiency as high as 66%. The gullet design of the blade seems to play an important role in affecting the amount of dust releasing as well as the collection efficiency of the passive dust controls.

Development and implementation of new generation cyclone facilities to improve efficiency of iron ore beneficiation and dust collection during its processing

Average iron content in industrial ores decreases from year to year. To use them in the processes of agglomeration and pelletizing, enrichment is necessary, accompanied by abundant emission of dust. A significant amount of iron is lost in tailings at existing magnetic enrichment technologies. Therefore, the development and implementation of new generation cyclone facilities to increase the efficiency of iron ore beneficiation and dust collection during its processing is an urgent scientific, practical and social task. The results of the of new generation cyclone facilities implementation for enrichment of iron ore and dust collection during its processing at the mining and processing factories of Kryvbas (Ukraine) are presented. It has been established that dry magnetic separation of finely crushed ore makes it possible to isolate a magnetic product with an iron content of 64-65%. The yield is up to 45%, the extraction of iron into the magnetic product is 73-75% in two-stage schemes. The degree of dust collection by the new generation cyclone facility is exponentially dependent on the speed of the cleaned flow, number and size of coaxial shells, as well as the diameter of dust particles) and is 1.23 times higher comparing with the previously used cyclone of the same size and capacity. The mobile magnetic field in the recommended cyclone allows to capture magnetic dust with an efficiency of up to 95%, and at the same time the dust is separated into a magnetic component (with an iron content of up to 65%) and a non-magnetic component (up to 12% of Fe) with an initial total iron content of up to 33%.

Experimental investigation and field application of pulse-jet cartridge filter in TBM tunneling construction of Qingdao Metro Line 8 subsea tunnel

In the process of large-scale urbanization, the increase of traffic flow has led to severe traffic jam in large and medium-sized cities. The metro can effectively relieve this problem, but large amounts of dust, which affects human health and safe production, will be generated during metro tunneling construction. While traditional methods such as water spray, ventilation and foam dedusting have some shortcomings, cartridge filters boast high dust collection efficiency, zero water consumption and no secondary pollution. Cartridge filters are suitable for the construction of subsea tunnels with water inrush problems. In order to solve the dust pollution during tunnel boring machine (TBM) tunneling in the Qingdao Metro Line 8 subsea tunnel, a cartridge filter was designed independently in this study. The optimization-factors were adopted to improve the uniformity of pulse-jet cleaning among filter cartridges. The optimized injection pipe was adopted in the design of pulse-jet cleaning system. Before the dust collection system in the TBM tunneling face was renovated, the dust concentration increased with the increase of running time. The total dust and respirable dust collection efficiencies of three measuring points were all lower than 70% when the axial flow fan ran for about 1 h and lower than 55% when it ran for about 4 h. After the renovation, the total dust and respirable dust collection efficiencies of three measuring points became higher than 92%, and the concentrations of total dust and respirable dust 20 m away from the cutterhead-changing platform were lower than 2 mg/m3. This indicates that the renovated cartridge filter effectively reduced the dust concentration and improved the working environment.

Enhancement of Cathode Dust Collection and its Application in Improving the Efficiency of Dry Electrostatic Precipitator

As the main equipment of flue gas dedusting in coal fired boiler, electrostatic precipitator (ESP) can meet the requirements of emission standard for air pollutants from coal-fired power plants through improving the efficiency of ESP and combining with desulfurization system while not installing wet ESP (WESP). This paper introduces the modifications of ESP cathode structure to improve the efficiency of dust collection by reducing the secondary dust loss at cathode. The application of cathode dust collection provides a reference for the improvement of ESP dust collection efficiency.

Design and optimization of waste heat recovery system for supercritical carbon dioxide coal-fired power plant to enhance the dust collection efficiency

The supercritical carbon dioxide (SCO2) power cycle is a potential power cycle for coal-fired power plants. In the SCO2 power systems provided in previous studies, the boiler exhaust temperature is about 120 °C. To enhance the power plant efficiency and the dust collection efficiency of electrostatic precipitator, SCO2 power systems should be advanced to cool the boiler exhaust fluegas to nearly 95 °C. Therefore, systems of waste heat recovery from low-temperature fluegas are proposed and optimized in this study. Thermodynamic and optimization models are developed. The double reheat recompression SCO2 cycle is optimized as benchmark system. The benchmark system is improved to decrease the exergy loss and boiler exhaust, decrease the irreversibility of air preheater, and recover waste heat of the SCO2 cycle to preheat air to the air preheater. When the main compressor intercooling or bypass fluegas ahead the air preheater is adopted, the temperature of boiler exhaust fluegas can be decreased to around 95 °C which can ensure a high dust collection efficiency of electrostatic precipitator. The power plant efficiency is also increased as a result. However, if only low-temperature economizer is integrated, then the power plant efficiency is enhanced slightly by 0.09%-pts. If the low temperature economizer is integrated with other system improvements, the power plant efficiency can be enhanced by 0.89%-pts. Exergy analysis is also performed to reveal the mechanisms of efficiency enhancement.

Prediction of Particle-Collection Efficiency for Vacuum-Blowing Cleaning System Based on Operational Conditions

The dust-collection system, as the core of a sweeper vehicle, directly inhales dust particles on the pavement. The influence of variable operational conditions on particle-separation performance was investigated using computational fluid dynamics (CFD) Euler–Lagrange multiphase model. The particle-separation performance efficiency and retention time were used to evaluate the dust-collection efficiency. The uniform design (UD) and multiple regression analysis (MRA) methods were employed to predict and optimize the effects of reverse-blowing flow rate, pressure drop, and traveling speed on separation efficiency. The results indicated that the dust-collection performance initially increased and then decreased with increasing reverse-blowing flow rate. As the pressure drop increased, there was an increase in total dust-collection efficiency. However, the efficiency decreased with increasing traveling speed. The regression model showed that the proposed approach was able to predict the particle collection efficiency accurately. In addition, the optimum operational conditions were obtained, namely a reverse-blowing flow rate of 2100 m3/h, a traveling speed of 5 km/h, and a pressure drop of 2400 Pa. The maximum particle-separation efficiency was 99.10%, which showed good agreement with the experimental results.

Study of face mask filtration efficiency to prevent fine dust to secure people’s right to health

In this study, we evaluated the filtering effect of the fine dust mask. Our objective research has secured credibility in the private sector. The performance of domestic fine dust masks is evaluated by three dust collection efficiencies, inspiratory resistance, and leakage rate according to KF grade in the health mask standard guidelines issued by the Ministry of Food and Drug Safety. Based on this, eight types of fine dust masks were evaluated for dust collection efficiency and face intake resistance. All masks showed good performance as the collection efficiency was 90%. The higher the KF grade, the higher the collection efficiency, but the inspiratory resistance had no correlation with the grade. According to the manufacturer's operation method, masks below the standard value may be distributed. Masks that are currently on the market have shown results that can be trusted. However, we hope that the system will be improved to validate whether the masks that meet the threshold are still being distributed.

Innovation for Trap Particle and Eliminate Germs in Air By Corona Electrostatic System

This article presents an innovation for trap particle and eliminate germs in air by corona electrostatic system. The air circulation rate is 165 cubic meters per hour by designing the power supply with IC#TL494. The IC#TLP250 uses separate ground and drive Power MOSFET#IRFP460 by bringing DC high voltage from the transformer#TLF14511 to the dust collector unit and the electron separation unit. By designing and building a machine capable of trapping dust particles smaller in size from 0.3 microns up to the results of the tests showed that the dust collecting efficiency of 95.37% from the experiment by measuring the amount of dust using Personal pump and the dust collection efficiency of 95.86% from measuring dust using Handy laser partical counter and part of electron separation can produce corona for producing ozone gas up to 3 ppm to eliminate bacteria in the air. The UV lamps for ozone emissions are reduced to 0.1 ppm for disaster prevention to users.

Filtration of dust in an electrostatically enhanced granular bed filter for high temperature gas cleanup

High temperature gas cleanup is an important technology. In order to develop an efficient filter for hot gas cleanup, three kinds of filters were built: 1) Rare earth tungsten (RE-W) cathode electrostatic precipitator (ESP), 2) classical granular bed filter (CGBF), and 3) electrostatically enhanced granular bed filter (EGBF). The effect of gas temperature, voltage, granule size, and bed height on the dust collection efficiency of the filters were investigated. It is found that the efficiency of the EGBF is the highest among the three filters. The efficiency of the double-zone RE-W cathode ESP ranks second, though decreasing collection area reduces the efficiency significantly. The efficiency of the CGBF is not high compared to the above two filters. On the whole, the EGBF is a very promising technology for hot gas cleanup, especially when cooperated with the RE-W thermionic emission cathode which is very suitable for particle charging at high temperature.

Simultaneous removal of particulates and NO by the catalytic bag filter containing V2O5-MoO3/TiO2

V2O5-MoO3/TiO2 based catalytic bag filters were developed for the simultaneous removal of particulates and NO in the temperature range of 200–250 °C. Good denitrification activity, dedust efficiency as well as high adhesion strength in the temperature range of 200–250 °C was exhibited. The study of catalyst powder for coating revealed that the increased V and Mo content in catalyst can elevate the low-temperature activity, and the chosen V10Mo10 sample for coating showed the best activity with 100% NO conversion at just 180 °C. The further research on catalytic bag filter found the low ratio of PTFE, high loading and long residence time (e.g., low filtration velocity or double layer filter) may help to achieve high DeNOx efficiency. The best performance was obtained with above 80% NO conversion at 200–250 °C even in the presence of SO2/H2O and 99.9% dust collection efficiency on the condition of 500 g/m2 loading, 10% PTFE, 0.5 m/min filtration velocity and double layers of filter, which demonstrated great feasibility for industrial application.

Measures to Improve Working Conditions and Reduce Dust and Gas Emissions in the Quarries of the Mining and Processing Plant

Research is crried out on the existing measures to suppress dust and gas emissions during mass explosions at the quarry of a mining and processing plant. Measures have been developed to reduce dust and gas emissions, taking into account the analysis of existing measures to suppress dust and gas emissions during mass explosions at the quarry of the mining plant of JSC «Lebedinsky MPP». Studies of surface active substances on the wettability of dust particles have been carried out. In order to improve working conditions, it was proposed to reduce dust and gas emissions by suppressing them in the source of formation using the method of wetting and sticking together of dust particles. The proposed engineering and technical solution can be used to reduce dust and gas emissions during mass explosions at the quarries of various mining and processing enterprises. The developed method is proposed to be used to ensure environmental safety and improve working conditions in industries with increased dust content by increasing the efficiency of dust collection.

Controlling fine particles in flue gas from lead-zinc smelting by plasma technology

With the aim of controlling the problem of fine particles in the flue gas of lead-zinc smelting, a low-temperature plasma-electrocoagulation and electric bag composite dedusting experimental platform was designed by combining electrocoagulation and electric bag composite dust removal technology based on the research of low-temperature plasma technology. Firstly, the properties of fine particles in flue gas from lead-zinc smelting were analyzed, and the effects of input voltage, filter wind speed, dust concentration, and pulse-jet ash-cleaning cycle on the dust collection efficiency of the integrated device were studied. Then, the energy efficiency of the integrated technology was analyzed, and the control mechanism of the fine particles was revealed. The experimental results show that the integrated technology of low-temperature plasma-electrocoagulation and electric bag composite dust removal achieves a fine particle removal efficiency of more than 99.99% and the energy consumption per unit mass of the dust is only 0.008 kW · h/g. The integrated technology has broad application prospects and far-reaching practical significance for the lead-zinc smelting industry to achieve ultra-low emission targets for flue gas and achieve energy-saving and emission reduction effects.

Dust Collection Efficiency, Inhalation Pressure, and CO 2 Concentration in Health Masks

Dust Collection Efficiency, Inhalation Pressure, and CO 2 Concentration in Health Masks

Characteristics of dust-collection efficiency and ozone emission by high-voltage electrode shape of electrostatic precipitator for subway tunnel environment

The air pollution level of particulate matters in subway tunnel environments is severe. The present study conducted experimental measurements and analyses on dust-collection efficiencies and ozone emission rates in a lab-scale wind tunnel to determine a high-voltage electrode shape suitable for an electrostatic precipitator to remove airborne particles in subway tunnels. Six high-voltage electrode shapes (saw-type, few-saw-type, short-saw-type, tree-type, wave-type, and spike-type) were tested. The results indicate that while breakdown voltage of the spike-type high-voltage electrode was 66 % of other electrode shapes, its dust-collection efficiency per unit voltage was similar to that of other electrode shapes. However, the dust-collection efficiency per unit of power in the spike-type high-voltage electrode was significantly low. Moreover, the wave-type high-voltage electrode shape had 20 % lower dust-collection efficiency than the saw-type and tree-type high-voltage electrode shapes under conditions of low voltage and high flow velocities. Ozone emission rates for all shapes increased proportionally to the electric current. However, ozone emission rates for each high-voltage electrode shape are varied as 12–23 μg/s per mA. The saw-type and tree-type high-voltage electrode shapes were superior in terms of dust collection, 90 % collection efficiency was shown at about 1.5 W/(m/s)2. The saw-type had a lower ozone emission rate (16.4 μg/s per mA) than the tree-type (19.6 μg/s per mA). Thus, the saw-type shape was the most suitable as a high-voltage electrode in the electrostatic precipitator for removing airborne particles in a subway. The results also indicate that both dust-collection efficiencies and ozone emission rates should be evaluated concurrently when evaluating electrostatic precipitator high-voltage electrodes.

Identification of gas-liquid two-phase flow patterns in dust scrubber based on wavelet energy entropy and recurrence analysis characteristics

For a wet dust scrubber, dust collection efficiency is tightly connected with the gas-liquid two-phase flow pattern. Using the characteristic parameters selected by current flow pattern identification methods, regions of significant coincidence exist among different patterns, thereby leading to a decline in the identification efficiency. In this study, a new method for processing the wavelet decomposition signal of the dust collector pressure was proposed to obtain the characteristic parameters that distinguish the flow pattern. Firstly, detailed information regarding the different frequency bands of the pressure signal was extracted via wavelet analysis. Then, in combination with the information entropy theory, wavelet energy entropy (WEE) was proposed to evaluate the uniformity of energy distribution in different frequency bands. The results show that WEE is sensitive to the change in gas-liquid two-phase flow patterns, and the corresponding distinguishing efficiency of flow patterns is 92.5%. There was only a small amount of crossover between the shear liquid curtain and entrainment air bubble pattern. For this, using the recursive analysis method (RAM), the characteristic recurrence plots (RP) and recurrence quantification analysis (RQA) of the original pressure signals and the wavelet decomposition signal with different frequency bands were obtained. Results show that the RP characteristics can intuitively reflect the gas-liquid flow state of different flow patterns. Although RQA characteristics are not sensitive to the change in low-level gas/liquid resonance flow pattern in the dust scrubber, it exhibits strong distinction to the evolution of other flow patterns. It effectively compensates for the crossover at the flow pattern distinguish between the shear liquid curtain and entrainment of air bubble using the parameters of the wavelet energy entropy. It is the highlight of this article that the combination of WEE and recurrence characteristics can effectively address the problems of high coincidence of flow pattern features in the dust scrubber.

Enhancement of particle collection efficiency considering the structural interplay: particle motion characteristics analysis

The vacuum-blowing cleaning system, utilizing positive and negative pressure mixed-delivery theory, has been adopted for the road sweeper vehicle. To enhance the solid particle separation performance and to evaluate the motion characteristics of inhaled particles under different structural parameters, the gas-solid flow in the vacuum-blowing cleaning system was investigated by using computational fluid dynamics (CFD) technology. The influence of the main structural parameters on the grade dust collection efficiency and average detention time of the inhaled particles was determined, such as suction-inlet diameter, suction-inlet inclination angle, and front baffle inclination angle. And the interplay between them was also investigated. In addition, a dust collection efficiency model was built, based on uniform design (UD) and multiple regression analysis (MRA), and subsequently verified via experiments. The results revealed that the structural parameters have significant influence on the dust collection performance. The suction-inlet diameter, front baffle inclination angle, and suction-inlet inclination angle exerted the highest, second-highest, and lowest influence, respectively. Furthermore, the interaction among structural parameters also influenced the collection performance. The highest, second-highest, and lowest levels of influence were determined for the inlet diameter/baffle inclination angle, inlet inclination angle/baffle inclination angle, and inlet diameter/inlet inclination interactions, respectively. The highest dust collection efficiency (i.e., 96.10%) and a short average detention time of particles in the chamber were realized under the following conditions: suction-inlet diameter and inclination angle: 200 mm and 110°, respectively, and front baffle inclination angle: 105°.

Wetting properties and performance of modified composite collectors in a membrane-based wet electrostatic precipitator

Abstract The membrane-based wet electrostatic precipitator (MWESP), exhibiting good control of PM2.5, has more and more widely applications. Considering traditional flexible collectors’ poor rigidity, this paper presents two modified composite collectors (MCC), smooth PVC plates covered by carbon fiber and glass fiber respectively. This paper tries to make a comparative study of performance characteristic between both the MCCs and a same size smooth PVC collector. We compared the collectors in the aspects as follows: water film thickness, ionic concentration,V-I characteristic and dust collection efficiency. Firstly, we compared the three collectors’ film forming abilities through a water film thickness measure experiment. Secondly, we measured the ionic concentrations and V-I characteristics, getting the electrical characteristics of the three collectors. At last, through an experiment of collection efficiencies, we compared the three collectors’ performance characteristics. The experiment results indicate that MCC with glass fiber not only can guarantee the rigidity of collector, but also proves best wetting properties and best performance characteristic with the water flow rate of 700L/h.

Simulation of Dust Particle Trajectories in an Electrostatic Probe with the Purpose of Increasing Its Efficiency

Formation of dust particles and clusters is observed in almost all modern fusion devices. Accumulation of dust in next-generation thermonuclear installations can significantly affect plasma parameters and lead to accumulation of unacceptably large amounts of tritium. The use of a specially developed electrostatic probe is planned in the international thermonuclear experimental reactor ITER to collect dust for further analysis. The article describes a numerical model of movement of dust particles in an electrostatic probe. Dust particle trajectories inside the probe are analyzed. Several electrostatic probe design modifications are proposed on the basis of the analysis in order to increase the efficiency of dust collection.

Increasing of an electrostatic probe capacity and efficiency for metal dust collection in ITER

Formation of dust particles and clusters is observed in almost all modern fusion devices. Accumulation of dust in next-generation thermonuclear installations can significantly affect plasma parameters and lead to accumulation of unacceptably large amounts of tritium. The use of a specially developed electrostatic probe is planned in the international thermonuclear experimental reactor ITER to collect dust for further analysis. The article describes a numerical model of dust particles movement in an electrostatic probe. Dust particles trajectories inside the probe were analyzed. Several electrostatic probe design modifications were proposed on the basis of the analysis in order to increase the efficiency of dust collection.

Моделирование процессов и разработка мероприятий по сокращению пылегазовыделения на карьерах горно-обогатительного комбината

Existing measures for the suppression of dust and gas emissions during mass explosions at the quarry of a mining and processing plant were investigated. Measures have been developed to reduce dust and gas emissions, taking into account the analysis of existing measures to suppress dust and gas emissions from mass explosions in the open pit of the mining and processing plant of Lebedinsky GOK. The studies of surface active substances on the wettability of dust particles. In order to improve working conditions, it was proposed to reduce dust and gas emissions by suppressing them at the source of education, using the method of wetting and sticking of dust particles. The proposed engineering - technical solution can be used to reduce dust and gas emissions during massive explosions in the quarries of various mining and processing enterprises. The developed method is proposed to be used to ensure environmental safety and improve working conditions in industries with high dustiness by increasing the efficiency of dust collection.