Dust removal from pyrolytic vapors at high temperatures is an obstacle to the industrialization of the coal pyrolysis process.In this work,a granular bed with expanded perlites as filtration media was designed and int...Dust removal from pyrolytic vapors at high temperatures is an obstacle to the industrialization of the coal pyrolysis process.In this work,a granular bed with expanded perlites as filtration media was designed and integrated into a 10 t·d^(–1)coal pyrolysis facility.The testing results showed that around 97.56%dust collection efficiency was achieved.As a result,dust content in tar was significantly lowered.The pressure drop of the granular bed maintained in the range of 356 Pa to 489 Pa.The dust size in the effluent after filtration exhibited a bimodal distribution,which was attributed to the heterogeneity of the dust components.The effects of filtration bed on pyrolytic product yields were also discussed.A modified filtration model based on the macroscopic phenomenological theory was proposed to describe the performance of the granular bed.The computation results were well agreed with the experimental data.展开更多
Understanding the relationship between forest management and water use efficiency(WUE)is important for evaluating forest adaptability to climate change.However,the effects of thinning and understory removal on WUE and...Understanding the relationship between forest management and water use efficiency(WUE)is important for evaluating forest adaptability to climate change.However,the effects of thinning and understory removal on WUE and its key controlling processes are not well understood,which limits our comprehension of the physiological mechanisms of various management practices.In this study,four forest management measures(no thinning:NT;understory removal:UR;light thinning:LT;and heavy thinning:HT)were carried out in Pinus massoniana plantations in a subtropical region of China.Photosynthetic capacity and needle stable carbon isotope composition(δ^(13)C)were measured to assess instantaneous water use efficiency(WUE_(inst))and long-term water use efficiency(WUE_(i)).Multiple regression models and structural equation modelling(SEM)identified the effects of soil properties and physiological performances on WUE_(inst)and WUE_(i).The results show that WUE_(inst)values among the four treatments were insignificant.However,compared with the NT stand(35.8μmol·mol^(-1)),WUE_(i)values significantly increased to 41.7μmol·mol^(-1)in the UR,50.1μmol·mol^(-1)in the LT and 46.6μmol·mol^(-1)in HT treatments,largely explained by photosynthetic capacity and soil water content.Understory removal did not change physiological performance(needle water potential and photosynthetic capacity).Thinning increased the net photosynthetic rate(A_n)but not stomatal conductance(g_s)or predawn needle water potential(ψ_(pd)),implying that the improvement in water use efficiency for thinned stands was largely driven by radiation interception than by soil water availability.In general,thinning may be an appropriate management measure to promote P.massoniana WUE to cope with seasonal droughts under future extreme climates.展开更多
To improve the poor efficiency of the dust removal system in the plasma cutting station of automotive longitudinal beams,and reduce the cutting surface quality degradation due to dust,a bottom-side suction dust remova...To improve the poor efficiency of the dust removal system in the plasma cutting station of automotive longitudinal beams,and reduce the cutting surface quality degradation due to dust,a bottom-side suction dust removal system is designed,and the dust removal effect is optimized through the setting of the following dampers and diversion plates.The result of numerical simulation indicates that the particle collection rate can reach 99.44%,and the field test also proves the effectiveness of the dust removal system,which is of guiding significance for the transformation of other similar dust removal systems.展开更多
To master theoretical calculation for dust removal efficiency of high pressure atomization in an underground coal mine, the corresponding atomization characteristics and dust removal efficiency were both comprehensive...To master theoretical calculation for dust removal efficiency of high pressure atomization in an underground coal mine, the corresponding atomization characteristics and dust removal efficiency were both comprehensively studied in theory by virtue of related theories of hydromechanics and aerosol.According to actual measurements of flow coefficients and atomization angles of X-type swirl nozzle,computational formula was derived for atomized particle sizes of such a nozzle in conjunction with relevant empirical equation. Moreover, a mathematical model for applying high pressure atomization to dust removal in underground coal mine was also established to deduce theoretical computation formula of fractional efficiency. Then, Matlab was adopted to portray the relation curve between fractional efficiency and influence factors. In addition, a theoretical formula was also set up for removal efficiency of respirable dust and total coal dust based on dust size and frequency distribution equations. In the end,impacts of dust characteristic parameters on various dust removal efficiencies were analyzed.展开更多
In order to enhance the atomization efficiency of atomizer, a new type of wind-spray dust controller combining the rotary-atomization and colliding broken of droplets was designed by the method of opening the water ci...In order to enhance the atomization efficiency of atomizer, a new type of wind-spray dust controller combining the rotary-atomization and colliding broken of droplets was designed by the method of opening the water circulation within the blades. The experiment test for dust controller was conducted by adjusting the following parameters: rotating speed, diversion hole-exit diameter, and colliding tooth angle. Results show that the atomization efficiency increases firstly then decreases with them. And the optimal parameters are obtained with rotating speed 1500-2200 r/min, diversion hole-exit diameter 2-2.5 mm and colliding tooth angle 30°-40°, and under these conditions the corresponding atomization efficiency tops to 95%. Then, the atomization situation under the optimal parameters is held from the aspect of simulation internal flow field and the results of droplet size(30-80 μm) are got, which indicates that the conclusion on the optimized parameters of dust controller is reasonable. The collecting efficiencies of different dust concentrations are determined, ranging from 85% to 98.4%, which shows that the designed dust controller can obtain a good atomizing effect and achieve well dustfall efficiency for the wetting dust control of coal mine.展开更多
The non-thermal plasma created by high voltage pulsed power supply can be used to remove sulfur dioxide in the air, but how to increase the removing efficiency is not clear. It is novel to apply the magnetic field in ...The non-thermal plasma created by high voltage pulsed power supply can be used to remove sulfur dioxide in the air, but how to increase the removing efficiency is not clear. It is novel to apply the magnetic field in removing SO2 as discussed in this paper. The mechanisms of removing sulfur dioxide by non-thermal plasma along with the application of the magnetic field are analyzed, and the related factors affecting the removal efficiency, such as the magnitude of pulsed voltage, the polarity of the pulse, the layout of the discharge electrode, especially the magnetic field are experimentally investigated. It can be concluded that the purification efficiency is improved significantly by applying the magnetic field.展开更多
The internal mechanism of the high hydrophobicity of the coal samples from the Pingdingshan mining area was studied through industrial,element,and surface functional group analysis.Laboratory testing and molecular dyn...The internal mechanism of the high hydrophobicity of the coal samples from the Pingdingshan mining area was studied through industrial,element,and surface functional group analysis.Laboratory testing and molecular dynamics simulations were employed to study the impact of three types of surfactants on the surface adsorption properties and wettability of highly hydrophobic bituminous coal.The results show that the surface of highly hydrophobic bituminous coal is compact,rich in inorganic minerals,and poorly wettable and that coal molecules are dominated by hydrophobic functional groups of aromatic rings and aliphatic structures.The wetting performance of surfactants as the intermediate carrier to connect coal and water molecules is largely determined by the interaction force between surfactants and coal(Fs-c)and the interaction force between surfactants and water(Fs-w),which effectively improve the wettability of modified coal dust via modifying its surface electrical properties and surface energy.A new type of wetting agent with a dust removal rate of 89%has been developed through discovery of a compound wetting agent solution with optimal wetting and settling performance.This paper provides theoretical and technical support for removing highly hydrophobic bituminous coal dust in underground mining.展开更多
Based onmultiphase flowtheory and capillary mechanics,the dimensionless bond number expression of the influence of string grille wire spacing on droplet spreading is derived.Taking a liquid film formed by spreading dr...Based onmultiphase flowtheory and capillary mechanics,the dimensionless bond number expression of the influence of string grille wire spacing on droplet spreading is derived.Taking a liquid film formed by spreading droplets based on Kelvin correlation,the Young-Laplace equation,and the Hagen-Poiseuille law,an equation for calculating the thickness and height of the liquid film is established with temperature,relative humidity and molar volume of liquid phase as independent variables.According to the theory of string grille filtration and dust removal,a dust removal efficiency calculation model covering the wet string grille wire group is constructed based on the liquid film thickness,height,wire diameter,water film area,and vortex shedding frequency.Finally,a theoretical analysis of the influence of water film area on the efficiency of wet string grille dust removal is carried out based on the spray pressure and the ratio of string grille wire distance to wire diameter.It is found that the effect of spray pressure on water film area and dust removal efficiency is more significant than the string grille wire distance diameter ratio.Moreover,the optimized combination of wet string grille wire distance diameter ratio 0.84,wind speed 3m/s and spray pressure 0.8 MPa is found,which could provide an important reference for engineering applications.展开更多
Energy demand is increasing while we are facing a depletion of fossils fuels, the main source of energy production in the world. These last years, photovoltaic (PV) system technologies are growing rapidly among altern...Energy demand is increasing while we are facing a depletion of fossils fuels, the main source of energy production in the world. These last years, photovoltaic (PV) system technologies are growing rapidly among alternative sources of energy to contribute to mitigation of climate change. However, PV system efficiency researches operating under West African weather conditions are nascent. The first objective of this study is to investigate the sensitivity of common monocrystalline PV efficiency to local meteorological parameters (temperature, humidity, solar radiation) in two contrasted cities over West Africa: Niamey (Niger) in a Sahelian arid area and Abidjan (Cote d’Ivoire) in atropical humid area. The second objective is to quantify the effect of dust accumulation on PV efficiency in Niamey (Niger). The preliminary results show that PV efficiency is more sensitive to high temperature change especially under Niamey climate conditions (warmer than Abidjan) where high ambient temperatures above 33°C lead to an important decrease of PV efficiency. Increase of relative humidity induces a decrease of PV efficiency in both areas (Niamey and Abidjan). A power loss up to 12.46% is observed in Niamey after 21 days of dust accumulation.展开更多
Methods to remove dust deposits by high-speed airflow have significant potential applications,with optimal design of flow velocity being the core technology.In this paper,we discuss the wind speed required for particl...Methods to remove dust deposits by high-speed airflow have significant potential applications,with optimal design of flow velocity being the core technology.In this paper,we discuss the wind speed required for particle removal from photovoltaic(PV)panels by compressed air by analyzing the force exerted on the dust deposited on inclined photovoltaic panels,which also included different electrification mechanisms of dust while it is in contact with the PV panel.The results show that the effect of the particle charging mechanism in the electric field generated by the PV panel is greatly smaller than the effect of the Van der Waals force and gravity,but the effect of the particle charged by the contact electrification mechanism in the electrostatic field is very pronounced.The wind speed required for dust removal from the PV panel increases linearly with the PV panel electric field,so we suggest that the nighttime,when the PV electric field is relatively small,would be more appropriate time for dust removal.The above results are of great scientific importance for accurately grasping the dust distribution law and for achieving scientific removal of dust on PV panels.展开更多
Dust collection systems represent a significant portion of a wood product manufacturer’s total electricity use. The system fan works against the static pressure of the entire system—the blast gates, the ductwork, an...Dust collection systems represent a significant portion of a wood product manufacturer’s total electricity use. The system fan works against the static pressure of the entire system—the blast gates, the ductwork, and the upstream or downstream cyclone and/or baghouse. A poor system design (e.g., sharp elbows or undersized ductwork) increases the total amount of static pressure in the system, the fan’s performance curve shifts, increasing the total brake horsepower required by the fan (up to the maximum point on the curve). Additionally, system designers may oversize a dust collection system to ensure adequate dust capture and transport, either to accommodate system expansion or simply to be conservative. Since theoretical fan energy use increases with its velocity cubed, this can be an expensive safety net. This paper presents a comprehensive literature review about industrial cyclone dust collectors energy saving in relation to management, technologies, and policies. Energy-saving technologies like high-efficiency motors (HEMs), variable-speed drives (VSDs), leak detection, and pressure drop reduction have all been examined. Based on energy saving technologies results, it has been found that in the industrial sectors, a sizeable amount of electric energy, and utility bill can be saved using these technologies. Finally, various energy-saving policies were reviewed.展开更多
The new dust removal technical route using the carbon-granular bed filter, packed of carbon particles with appropriate grade derive from an online-process vibration sieve, to replace the traditional baggy filter had b...The new dust removal technical route using the carbon-granular bed filter, packed of carbon particles with appropriate grade derive from an online-process vibration sieve, to replace the traditional baggy filter had been developed successfully for capturing the micro-carbon dusts produced from pulverization of petroleum coke, and the green close loop of carbon materials is thus completed in the combined pulverizing and classifying system and pulverized carbon dust removal process. The high dust removal efficiency greater than 99%, low outlet dust concentration less than 100mg·m-3, low pressure drop through dust filtration chamber less than 980Pa, simple and easy design, and flexible and stable operation were achieved also with the carbon-granular bed filter in both bench and industrial scale operations.展开更多
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 effi...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.展开更多
The cyclone dust collector is an important subsystem of straw crushers used in agriculture.In the present study,a new type of dust collector with involute morphology is proposed to obtain better dust removal efficienc...The cyclone dust collector is an important subsystem of straw crushers used in agriculture.In the present study,a new type of dust collector with involute morphology is proposed to obtain better dust removal efficiency with respect to that of classical tangential and spiral dust collectors.A discrete phase model(DPM)method is used in synergy with a turbulence model,and the SIMPLE algorithm to simulate the flow field inside the dust collector and the related particle dynamics.It is shown that the internal flow field features a primary swirl,a secondary swirl and blockage effects.Moreover,for the involute dust collector,the tangential velocity in the initial stage and the pressure in the high-pressure area are larger than those obtained for the classical types.The dust removal efficiency is 37.11%,25.3%,and 16.37%for the involute type dust collector,the tangential type and the spiral type,respectively.展开更多
With the rapid industrialization and urbanization,the demand for air quality management is more and more urgent.High temperature dust filtration is one important environmental management technology.Porous ceramics are...With the rapid industrialization and urbanization,the demand for air quality management is more and more urgent.High temperature dust filtration is one important environmental management technology.Porous ceramics are used as filter materials in the field of high-temperature dust filtration because of their unique advantages such as high filtration efficiency,as well as high temperature stability,particle loss resistance,corrosion resistance and durability.This paper mainly introduced several common preparation techniques of porous ceramics,including the traditional organic foam impregnation method,foaming method,in-situ combustion method,pore-forming method and other new methods such as the template method,gel injection molding method,freeze-drying method,multi-component co-precipitation method and hydrogel method.The principle,advantages and disadvantages of these preparation technologies and their research status were described.The application of these technologies in the field of high temperature dust filtration was briefly reviewed.Finally,the application prospect of the porous ceramics in the field of high temperature dust filtration was prospected.展开更多
基金financial support from the National Key Research and Development Program of China(2018YFB0605003).
文摘Dust removal from pyrolytic vapors at high temperatures is an obstacle to the industrialization of the coal pyrolysis process.In this work,a granular bed with expanded perlites as filtration media was designed and integrated into a 10 t·d^(–1)coal pyrolysis facility.The testing results showed that around 97.56%dust collection efficiency was achieved.As a result,dust content in tar was significantly lowered.The pressure drop of the granular bed maintained in the range of 356 Pa to 489 Pa.The dust size in the effluent after filtration exhibited a bimodal distribution,which was attributed to the heterogeneity of the dust components.The effects of filtration bed on pyrolytic product yields were also discussed.A modified filtration model based on the macroscopic phenomenological theory was proposed to describe the performance of the granular bed.The computation results were well agreed with the experimental data.
基金supported by the National Key Research and Development Program of China(2016YFD0600201)the National Nonprofit Institute Research Grant of CAF(CAFYBB2017ZB003)+1 种基金the National Natural Science Foundation of China(3187071631670720)。
文摘Understanding the relationship between forest management and water use efficiency(WUE)is important for evaluating forest adaptability to climate change.However,the effects of thinning and understory removal on WUE and its key controlling processes are not well understood,which limits our comprehension of the physiological mechanisms of various management practices.In this study,four forest management measures(no thinning:NT;understory removal:UR;light thinning:LT;and heavy thinning:HT)were carried out in Pinus massoniana plantations in a subtropical region of China.Photosynthetic capacity and needle stable carbon isotope composition(δ^(13)C)were measured to assess instantaneous water use efficiency(WUE_(inst))and long-term water use efficiency(WUE_(i)).Multiple regression models and structural equation modelling(SEM)identified the effects of soil properties and physiological performances on WUE_(inst)and WUE_(i).The results show that WUE_(inst)values among the four treatments were insignificant.However,compared with the NT stand(35.8μmol·mol^(-1)),WUE_(i)values significantly increased to 41.7μmol·mol^(-1)in the UR,50.1μmol·mol^(-1)in the LT and 46.6μmol·mol^(-1)in HT treatments,largely explained by photosynthetic capacity and soil water content.Understory removal did not change physiological performance(needle water potential and photosynthetic capacity).Thinning increased the net photosynthetic rate(A_n)but not stomatal conductance(g_s)or predawn needle water potential(ψ_(pd)),implying that the improvement in water use efficiency for thinned stands was largely driven by radiation interception than by soil water availability.In general,thinning may be an appropriate management measure to promote P.massoniana WUE to cope with seasonal droughts under future extreme climates.
基金Changchun Science and Technology Development Plan Project,Automobile Rolling Line Longitudinal Beam Cutting Process Under the Extraction and Dust Removal Process Test and Research,Project Approval No.21ST04。
文摘To improve the poor efficiency of the dust removal system in the plasma cutting station of automotive longitudinal beams,and reduce the cutting surface quality degradation due to dust,a bottom-side suction dust removal system is designed,and the dust removal effect is optimized through the setting of the following dampers and diversion plates.The result of numerical simulation indicates that the particle collection rate can reach 99.44%,and the field test also proves the effectiveness of the dust removal system,which is of guiding significance for the transformation of other similar dust removal systems.
基金Financial provided by the National Natural Science Foundation of China (Nos. 51574123 and U1361118)the China Postdoctoral Science Foundation (No. 2015M 582118)
文摘To master theoretical calculation for dust removal efficiency of high pressure atomization in an underground coal mine, the corresponding atomization characteristics and dust removal efficiency were both comprehensively studied in theory by virtue of related theories of hydromechanics and aerosol.According to actual measurements of flow coefficients and atomization angles of X-type swirl nozzle,computational formula was derived for atomized particle sizes of such a nozzle in conjunction with relevant empirical equation. Moreover, a mathematical model for applying high pressure atomization to dust removal in underground coal mine was also established to deduce theoretical computation formula of fractional efficiency. Then, Matlab was adopted to portray the relation curve between fractional efficiency and influence factors. In addition, a theoretical formula was also set up for removal efficiency of respirable dust and total coal dust based on dust size and frequency distribution equations. In the end,impacts of dust characteristic parameters on various dust removal efficiencies were analyzed.
基金Project(U1261107)supported by the Joint Funds of the National Natural Science Foundation of China
文摘In order to enhance the atomization efficiency of atomizer, a new type of wind-spray dust controller combining the rotary-atomization and colliding broken of droplets was designed by the method of opening the water circulation within the blades. The experiment test for dust controller was conducted by adjusting the following parameters: rotating speed, diversion hole-exit diameter, and colliding tooth angle. Results show that the atomization efficiency increases firstly then decreases with them. And the optimal parameters are obtained with rotating speed 1500-2200 r/min, diversion hole-exit diameter 2-2.5 mm and colliding tooth angle 30°-40°, and under these conditions the corresponding atomization efficiency tops to 95%. Then, the atomization situation under the optimal parameters is held from the aspect of simulation internal flow field and the results of droplet size(30-80 μm) are got, which indicates that the conclusion on the optimized parameters of dust controller is reasonable. The collecting efficiencies of different dust concentrations are determined, ranging from 85% to 98.4%, which shows that the designed dust controller can obtain a good atomizing effect and achieve well dustfall efficiency for the wetting dust control of coal mine.
基金The project supported by the Teaching and Research Award Program for Outstanding Young Teachers in Higher EducationInstitutions under the MOE, China (No. 123-2002)
文摘The non-thermal plasma created by high voltage pulsed power supply can be used to remove sulfur dioxide in the air, but how to increase the removing efficiency is not clear. It is novel to apply the magnetic field in removing SO2 as discussed in this paper. The mechanisms of removing sulfur dioxide by non-thermal plasma along with the application of the magnetic field are analyzed, and the related factors affecting the removal efficiency, such as the magnitude of pulsed voltage, the polarity of the pulse, the layout of the discharge electrode, especially the magnetic field are experimentally investigated. It can be concluded that the purification efficiency is improved significantly by applying the magnetic field.
文摘The internal mechanism of the high hydrophobicity of the coal samples from the Pingdingshan mining area was studied through industrial,element,and surface functional group analysis.Laboratory testing and molecular dynamics simulations were employed to study the impact of three types of surfactants on the surface adsorption properties and wettability of highly hydrophobic bituminous coal.The results show that the surface of highly hydrophobic bituminous coal is compact,rich in inorganic minerals,and poorly wettable and that coal molecules are dominated by hydrophobic functional groups of aromatic rings and aliphatic structures.The wetting performance of surfactants as the intermediate carrier to connect coal and water molecules is largely determined by the interaction force between surfactants and coal(Fs-c)and the interaction force between surfactants and water(Fs-w),which effectively improve the wettability of modified coal dust via modifying its surface electrical properties and surface energy.A new type of wetting agent with a dust removal rate of 89%has been developed through discovery of a compound wetting agent solution with optimal wetting and settling performance.This paper provides theoretical and technical support for removing highly hydrophobic bituminous coal dust in underground mining.
基金We thank Esther Posner,PhD,from Edanz Group China(www.liwenbianji.cn/ac)for English language editing on an earlier draft of this manuscript.This work was supported by the 2017 Hunan Provincial Graduate Research Innovation Project of China(No.CX2017B649)the National Natural Science Foundation of China(No.51774134)+2 种基金the Excellent Youth Project of Hunan Provincial Department of Education(No.19B223)the Hunan Provincial Natural Science Foundation of China(No.2019JJ60044)the Hunan Provincial Natural Science Foundation of China(No.2018JJ64028).
文摘Based onmultiphase flowtheory and capillary mechanics,the dimensionless bond number expression of the influence of string grille wire spacing on droplet spreading is derived.Taking a liquid film formed by spreading droplets based on Kelvin correlation,the Young-Laplace equation,and the Hagen-Poiseuille law,an equation for calculating the thickness and height of the liquid film is established with temperature,relative humidity and molar volume of liquid phase as independent variables.According to the theory of string grille filtration and dust removal,a dust removal efficiency calculation model covering the wet string grille wire group is constructed based on the liquid film thickness,height,wire diameter,water film area,and vortex shedding frequency.Finally,a theoretical analysis of the influence of water film area on the efficiency of wet string grille dust removal is carried out based on the spray pressure and the ratio of string grille wire distance to wire diameter.It is found that the effect of spray pressure on water film area and dust removal efficiency is more significant than the string grille wire distance diameter ratio.Moreover,the optimized combination of wet string grille wire distance diameter ratio 0.84,wind speed 3m/s and spray pressure 0.8 MPa is found,which could provide an important reference for engineering applications.
文摘Energy demand is increasing while we are facing a depletion of fossils fuels, the main source of energy production in the world. These last years, photovoltaic (PV) system technologies are growing rapidly among alternative sources of energy to contribute to mitigation of climate change. However, PV system efficiency researches operating under West African weather conditions are nascent. The first objective of this study is to investigate the sensitivity of common monocrystalline PV efficiency to local meteorological parameters (temperature, humidity, solar radiation) in two contrasted cities over West Africa: Niamey (Niger) in a Sahelian arid area and Abidjan (Cote d’Ivoire) in atropical humid area. The second objective is to quantify the effect of dust accumulation on PV efficiency in Niamey (Niger). The preliminary results show that PV efficiency is more sensitive to high temperature change especially under Niamey climate conditions (warmer than Abidjan) where high ambient temperatures above 33°C lead to an important decrease of PV efficiency. Increase of relative humidity induces a decrease of PV efficiency in both areas (Niamey and Abidjan). A power loss up to 12.46% is observed in Niamey after 21 days of dust accumulation.
基金Project supported by the National Natural Science Foundation of China(Grant No.12064034)the Leading Talents Project of Science and Technology Innovation in Ningxia Hui Autonomous Region,China(Grant No.2020GKLRLX08)+1 种基金the Natural Science Foundation of Ningxia Hui Autonomous Region,China(Grant Nos.2022AAC03643 and2022AAC03117)the Major Science and Technology Project of Ningxia Hui Autonomous Region,China(Grant No.2022BDE03006)。
文摘Methods to remove dust deposits by high-speed airflow have significant potential applications,with optimal design of flow velocity being the core technology.In this paper,we discuss the wind speed required for particle removal from photovoltaic(PV)panels by compressed air by analyzing the force exerted on the dust deposited on inclined photovoltaic panels,which also included different electrification mechanisms of dust while it is in contact with the PV panel.The results show that the effect of the particle charging mechanism in the electric field generated by the PV panel is greatly smaller than the effect of the Van der Waals force and gravity,but the effect of the particle charged by the contact electrification mechanism in the electrostatic field is very pronounced.The wind speed required for dust removal from the PV panel increases linearly with the PV panel electric field,so we suggest that the nighttime,when the PV electric field is relatively small,would be more appropriate time for dust removal.The above results are of great scientific importance for accurately grasping the dust distribution law and for achieving scientific removal of dust on PV panels.
文摘Dust collection systems represent a significant portion of a wood product manufacturer’s total electricity use. The system fan works against the static pressure of the entire system—the blast gates, the ductwork, and the upstream or downstream cyclone and/or baghouse. A poor system design (e.g., sharp elbows or undersized ductwork) increases the total amount of static pressure in the system, the fan’s performance curve shifts, increasing the total brake horsepower required by the fan (up to the maximum point on the curve). Additionally, system designers may oversize a dust collection system to ensure adequate dust capture and transport, either to accommodate system expansion or simply to be conservative. Since theoretical fan energy use increases with its velocity cubed, this can be an expensive safety net. This paper presents a comprehensive literature review about industrial cyclone dust collectors energy saving in relation to management, technologies, and policies. Energy-saving technologies like high-efficiency motors (HEMs), variable-speed drives (VSDs), leak detection, and pressure drop reduction have all been examined. Based on energy saving technologies results, it has been found that in the industrial sectors, a sizeable amount of electric energy, and utility bill can be saved using these technologies. Finally, various energy-saving policies were reviewed.
基金the Fujian Provincial Science and Technology Council Grant (No. 2001H043).
文摘The new dust removal technical route using the carbon-granular bed filter, packed of carbon particles with appropriate grade derive from an online-process vibration sieve, to replace the traditional baggy filter had been developed successfully for capturing the micro-carbon dusts produced from pulverization of petroleum coke, and the green close loop of carbon materials is thus completed in the combined pulverizing and classifying system and pulverized carbon dust removal process. The high dust removal efficiency greater than 99%, low outlet dust concentration less than 100mg·m-3, low pressure drop through dust filtration chamber less than 980Pa, simple and easy design, and flexible and stable operation were achieved also with the carbon-granular bed filter in both bench and industrial scale operations.
文摘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.
基金supported by the Independent Research Fund of the State Key Laboratory of Mining Response and Disaster Prevention and Control in Deep Coal Mines(No.SKLMRDPC20ZZ06)and the Program in the Youth Elite Support Plan in Universities of Anhui Province(No.gxyq2020013).
文摘The cyclone dust collector is an important subsystem of straw crushers used in agriculture.In the present study,a new type of dust collector with involute morphology is proposed to obtain better dust removal efficiency with respect to that of classical tangential and spiral dust collectors.A discrete phase model(DPM)method is used in synergy with a turbulence model,and the SIMPLE algorithm to simulate the flow field inside the dust collector and the related particle dynamics.It is shown that the internal flow field features a primary swirl,a secondary swirl and blockage effects.Moreover,for the involute dust collector,the tangential velocity in the initial stage and the pressure in the high-pressure area are larger than those obtained for the classical types.The dust removal efficiency is 37.11%,25.3%,and 16.37%for the involute type dust collector,the tangential type and the spiral type,respectively.
文摘With the rapid industrialization and urbanization,the demand for air quality management is more and more urgent.High temperature dust filtration is one important environmental management technology.Porous ceramics are used as filter materials in the field of high-temperature dust filtration because of their unique advantages such as high filtration efficiency,as well as high temperature stability,particle loss resistance,corrosion resistance and durability.This paper mainly introduced several common preparation techniques of porous ceramics,including the traditional organic foam impregnation method,foaming method,in-situ combustion method,pore-forming method and other new methods such as the template method,gel injection molding method,freeze-drying method,multi-component co-precipitation method and hydrogel method.The principle,advantages and disadvantages of these preparation technologies and their research status were described.The application of these technologies in the field of high temperature dust filtration was briefly reviewed.Finally,the application prospect of the porous ceramics in the field of high temperature dust filtration was prospected.
