Improving the Energy Efficiency of Cyclone Dust Collectors for Wood Product Factories

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.

Contributions of the Secondary Jet to the Tangential Velocity Distribution and to the Collection Efficiency of the Fixed Guide Vane Type Axial Flow Cyclone Dust Collector

In order to control the maximum tangential velocity V?m(m/s)of the turbulent rotational air flow and the collection efficiencyηc(%)using the fly ash of the mean diameter X R50=5.57?m,two secondary jet nozzles were installed to the body of the axial flow cyclone dust collector with the body diameter D1=99mm.Then in order to estimate V?m(m/s),the conservation theory of the angular momentum flux with Ogawa combined vortex model was applied.The comparisons of the estimated results of V?m(m/s)with the measured results by the cylindrical Pitot-tube were shown in good agreement.And also the estimated collection efficienciesηcth(%)basing upon the cut-size Xc(?m)which was calculated by using the estimated V?m(m/s)and also the particle size distribution R(Xp)were shown a little higher values than the experimental results due to the re-entrainment of the collected dust.The best method for adjustment ofηc(%)related to the contribution of the secondary jet flow is principally to apply the centrifugal effect?c(1).Above stated results are described in detail.

Experimental investigation on atomization and collecting efficiency of wind-spray dust controller and its parameters optimization

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.

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.

Application of Mechanical Similarity Laws to the Collection Efficiencies of Geometrically Types of Uni-Flow Cyclone Dust Collectors

From the mechanical similarity point of view, the centrifugal effect, Ar, and the Stokes number, St, as well as the Reynolds number, Re_c for the motion of solid particles in the cyclone are the relevant parameters. In order to apply these similarity laws for the prediction of the characteristics of the collection efficiency, ηc, geometrically similar types of uni-flow cyclones were used. The body diameters of the cyclones were D_1=30, 50, 69 and 99 mm, respectively. The feed particle concentration of the fly-ash particles was up to C_o = 60g/m^3. From the experimental results: (1) the pressure drop, △pc, in the cyclones was a function of not only the Reynods number, Re_c, but also the body diameter, D_1; (2) the collection efficiency, η_c, did not always increase with decreasing body diameter but there existed an optimal body size; (3) application of the mechanical similarity laws to the collection efficiency was not always sufficient for estimating the collection efficiency, since the feed particle concentration was an additional important factor; (4) a new parameter which was the ratio, E_(pf), of the apparent separation energy, W_p, of the solid particles to the energy loss, E_c, of the gas flow in the cyclone was introduced for discussing the collection efficiency; (5) Fuchs theory, used to estimate the collection efficiency, was examined. Fuchs theory may be applied for high feed particle concentration.

Numerical Simulation of Dust Removal in the Cyclone Collector of a Straw Crusher Based on a Discrete Phase Model

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.

Estimation of Collection Efficiency Depended on FeedParticle Concentration for Axial Flow Cyclone DustCollector

A cyclone dust collector is applied in many industries. Especially the axial flow cyclone is the mostsimple construction and it keeps high reliability for maintenance. On the other hand, the collectionefficiency of the cyclone depends not only on the inlet gas velocity but also on the feed particle concentration. The collection efficiency increases with increasing feed particle concentration. However untilnow the problem of how to estimate the collection efficiency depended on the feed particle concentrationis remained except the investigation by Muschelknautz & Brunner~[6]. Therefore in this paper one ofthe estimate method for the collection efficiency of the axial flow cyclones is proposed. The applicationto the geometrically similar type of cyclone of the body diameters D_1=30, 50, 69 and 99 mm showedin good agreement with the experimental results of the collection efficiencies which were described indetail in the paper by Ogawa & Sugiyama~[8].

包钢高炉喷吹煤粉利用率的测定

利用透射光偏光显微镜,对包钢高炉重力除尘灰、旋风除尘灰和布袋除尘灰中的碳素种类进行定性和定量分析,以测定高炉喷吹煤粉利用率。测定结果表明,3号高炉喷吹煤粉利用率上下限分别为89.03%和79.46%,4号高炉的喷吹煤粉利用率上下限分别为91.51%和84.14%。认为,3号高炉和4号高炉所使用喷吹煤粉来自同一系列,因此可以通过采取稳定煤粉粒度波动、优化富氧鼓风和提高入炉焦炭强度等措施,来提高喷吹煤粉利用率。

旋风滤布除尘器的除尘性能研究

为了解决传统旋风除尘器对颗粒捕集效率差、袋式除尘器使用寿命短等问题,将传统旋风除尘与滤布除尘有效结合,形成一种优势互补的一体式旋风滤布除尘装置。采用数值模拟和试验相结合的方法,探究在不同出口压力的条件下,旋风滤布除尘器的除尘效率及压力损失情况。利用Fluent软件对旋风滤布除尘器的除尘性能进行模拟,模拟采用雷诺应力模型(Reynolds Stress Model, RSM)和多相流模型(Discrete Phase Model, DPM)。通过搭建试验平台,测试除尘装置的除尘性能,验证数值模拟的可靠性与正确性。结果表明:旋风滤布除尘器的除尘效率相对于旋风除尘有明显的提高,旋风滤布除尘器的除尘效率与出口负压呈正相关,旋风滤布除尘总效率随出口负压的增加而逐渐增加,且旋风滤布除尘器除尘效率的最小值都高于旋风除尘部分除尘效率的最大值;旋风滤布除尘器的压力损失随出口负压的增加而线性增大,压力损失增大使得除尘器损耗的功率也增多,且压力损失的上升速度快于除尘效率的提升速度;在旋风滤布除尘器中,负压增大后,旋风除尘捕获大粒径颗粒,逃逸到滤布部分的颗粒粒径都较小,降低了滤布被大颗粒划破的风险,提高了滤袋的使用寿命。

低阻文丘里振弦栅除尘系统内流场模拟研究

为探究除尘系统流场分布情况以及粉尘与液滴颗粒对除尘系统性能的影响,运用Fluent模拟研究气态单相流、气固两相流和气固液三相流的流场分布情况,分析除尘器在不同工况条件下压力与流场分布规律以及颗粒的运动情况。结果表明:除尘系统流场主要受除尘器结构的影响,受粉尘颗粒的影响较小;液滴颗粒的存在会提高系统的除尘效率;加入液滴颗粒后,粉尘运动凌乱度增强,与液滴碰撞作用加强,促进了细微粉尘的凝聚,但同时会影响除尘器流场稳定性,增加除尘系统阻力损失。

岩巷掘进工作面控风净化除尘系统设计与应用

针对岩巷掘进工作面压风风流携带迎头粉尘弥漫扩散造成粉尘治理难度大的问题,提出了掘进面“控风—净化”综合粉尘治理方案,构建了由湿式旋流除尘器、易装拆控尘装置、便移式负压风筒等组成的岩巷掘进面高效除尘系统,对比分析了除尘系统的不同安装方案对除尘效果的影响;综合考虑现场除尘效果与劳动强度,明确了湿式旋流除尘器最佳安装方案以及负压风筒与控尘装置的最优安装位置。在某矿辅运大巷岩巷掘进面进行了现场应用,结果表明:当负压风筒安装至通风风筒对侧,吸尘口距巷道迎头3 m,控尘装置位于通风风筒压风口后方5 m时,迎头高浓度粉尘在通风风筒压风、控尘装置控风及除尘器抽尘共同作用下被控制在迎头附近,并不断向负压风筒吸尘口运移最终被除尘器抽入净化,除尘器前方全尘和呼尘除尘效率分别达到95.9%和94.9%以上,除尘器后方全尘和呼尘除尘效率分别达到96.5%和95.4%以上,显著提升了巷道可见度,有效解决了岩巷掘进面通风造成的粉尘治理难题。

PTFE针刺毡滤料覆膜牢度研究

随着环保标准的不断提高,国家对工业烟气中微细颗粒物的排放提出了更高的要求。目前,工业除尘滤料中基于聚四氟乙烯(Polytetrafluoroethylene, PTFE)膜的覆膜针刺毡滤料对微细颗粒物有较高的过滤效率。然而,PTFE膜在长期使用过程中有脱落的风险,进而影响除尘器的除尘效果。因此,PTFE膜与针刺毡滤料基底间的覆膜牢度至关重要。研究选取市场上常用的5种PTFE覆膜滤料,对其覆膜牢度进行系统评估,并分析覆膜牢度的影响因素。结果显示:同样以PTFE为基底的覆膜滤料的覆膜牢度最大,其值大于0.074 MPa;以芳纶、聚酰亚胺(Polyimide, P84)、聚苯硫醚(Polyphenylene Sulfide, PPS)针刺毡滤料为基底的覆膜滤料覆膜牢度为0.027~0.029 MPa。经分析,覆膜的处理温度对覆膜牢度有较大影响,而实际处理温度需根据针刺毡基底的材质选择;针刺毡基底表面的纤维面积占比也是影响覆膜牢度的因素之一。此外,研究对膜脱落后滤料的过滤性能变化进行评估发现,膜脱落对滤料过滤性能有较大影响,其中P84覆膜滤料的膜脱落后过滤性能变化幅度最大,对PM2.5的过滤效率由95.25%降低至78.66%。研究成果对覆膜滤料的选择以及增强覆膜滤料的覆膜牢度具有指导作用。

高寒地区平板热管式太阳能集热系统热性能研究

基于呼和浩特地区高寒气候条件,搭建两组完全一致的平板热管式太阳能集热系统,通过实验对比分析太阳辐射强度、传热工质流量、集热板表面积尘等因素对集热器瞬时集热效率以及系统热性能的影响。结果表明,在同等外界条件下,集热器的集热效率随着工质流量的增加而增大,集热效率与太阳辐射强度变化趋势相近,随积尘密度的增加,集热板表面积尘导致系统的得热量减少,集热性能下降。

掘锚工作面高效湿式除尘器结构优化设计

针对掘锚工作面使用原掘锚机自带液动除尘器降尘效果差的问题,从掘锚工作面实际供风与除尘器风量关系、有无控风等方面分析了降尘效果不理想的原因,重新设计了一种高效湿式除尘器。通过增大除尘风机风量、优化设计除尘器的内部结构和外形尺寸、结合现场控风、喷雾等综合措施以达到改善作业现场环境的目的。现场测试结果表明,改进后的湿式除尘器总粉尘和呼吸性粉尘降尘效率分别为96.55%和91.01%,满足现场使用要求。

综掘工作面扰动拨流高效捕尘技术及配套装备研究

为了解决综掘工作面粉尘治理难题,消除粉尘爆炸的安全隐患,减少尘肺病的发生,对比了目前矿井已有的除尘系统,以香源煤业南集中轨道大巷为背景,对综掘工作面的粉尘运移规律及运移状态进行模拟分析,开发一套扰动拨流高效捕尘系统及装备,通过现场试验,除尘效率达到90%左右,在综掘工作面粉尘防治方面有着较好的效果。

矿用湿式过滤除尘器过滤单元过滤技术优化研究

为提升矿用湿式过滤除尘器呼吸性粉尘除尘效率,以除尘器过滤单元过滤参数为实验对象,搭建过滤单元实验平台,研究除尘器过滤单元过滤形式、过滤网层数/除雾垫厚度、孔径、过滤风速等对呼尘除尘效果和阻力的影响规律。研究结果表明:相同条件下,10层20目金属过滤网过滤板过滤性能最佳,阻力1 370 Pa,呼尘除尘效率90.7%;过滤风速取7.8 m/s,除尘器呼吸性粉尘除尘效率最高;采用冲击式惯性分离器与滤网融合设计的过滤板能有效避免出现堵死导致除尘器风机损坏。研究结果可为优化矿用湿式过滤除尘器结构、提升呼尘除尘效率提供依据。

高炉炼铁系统除尘工艺研究

为改善炼铁过程中的颗粒物排放问题,对高炉炼铁系统的除尘工艺进行研究。通过对现有除尘设备存在的问题进行分析,设计出改造方案,实施了一系列的改进措施,并对改造后的系统进行了性能评估。结果表明,改造后的除尘工艺能够有效降低颗粒物浓度,并提高系统的运行效率和稳定性。该研究为高炉炼铁系统的除尘工艺优化提供了有益的参考。

电除尘器在镍铁回转窑“袋改电”项目上的设计应用

主要是介绍采用C480板配侧部振打阴极系统的电除尘器在镍铁回转窑“袋改电”项目上的应用,考虑镍铁回转窑冶炼、某具体项目的烟尘特点,考虑“袋改电”改造项目场地情况,及考虑这些特点所采用的结构,以满足某具体项目的持续安全运行。

基于化工工艺的电石风险脱除工艺

电石法乙炔制备工艺中,除尘管道积尘无法有效清除,成为安全隐患。本文结合湿法电石制备乙炔工艺阐述了一种新型的电石粉尘除尘工艺,解决了此类问题,消除了安全隐患。

焦炉炉头烟集尘罩结构优化设计

为提高焦炉炉头烟气集尘罩的抽吸能效,对焦炉炉头烟排放过程特征进行分析,优化了炉头烟集尘罩结构设计,并对比分析了优化前后集尘罩对炉头烟尘的捕获效率和能力,结果表明:射流轨迹随着射流速度的提高逐渐趋于平稳状态,降低了顶端集尘罩吸收烟气的效率;传统集尘罩前端风速分布均小于优化后的集尘罩;当风机风量从1.0×10^(5)m^(3)/h减小7.0×10^(4)m^(3)/h时,优化后的集尘罩重新分配风量,使集尘罩前端和下端和位置的风速均在传统集尘罩以上,表明优化后的集尘罩在克服风量递减问题以及增强前端抽吸效能上具有显著的优势,有利于对沿导烟板扩散的烟气的捕集,强化了对炉头烟尘的捕获效率。