Pyrometallurgical Removal of Arsenic from Electrostatic Precipitators Dusts of Copper Smelting

This work describes the experimental results of pyrometallurgical removing of arsenic from the dust collected in the electrostatic copper precipitators within the gas cleaning system of a Copper Flash Smelting Furnace. The generation of dust in the copper smelting worldwide ranges from 2 - 15 wt% per ton of a copper concentrate. In Chile, copper smelters produce approximately 110 kt/y of dust with a concentration of arsenic between 1 and 15 wt%. The dust is a complex of metals oxides and sulfurs with copper concentrations greater than 10 wt% and relatively high silver concentrations. Since its high arsenic concentration, it is difficult to recover valuable metals through hydrometallurgical processes or by direct recirculation of the dust in a smelting furnace. Thus, the development of pyrometallurgical processes aimed at reducing the concentration of arsenic in the dust (<0.5 wt%) is the main objective of this study, giving particular attention to the production of a suitable material to be recirculated in operations of copper smelting. The work provides a detailed characterization of the dust including the Quantitative Evaluation of Minerals by Scanning Electron Microscopy (QEMSCAN), Scanning Electron Microscope-Energy Dispersive X-ray Analysis (SEM/EDS), X-Ray Diffraction (XRD), the elemental chemical analysis using Atomic Adsorption (AAS), and X-Ray Fluorescence (X-RF). By considering that arsenic volatilization requires a process of sulfidation-decomposition-oxidation, this work seeks to explore the roasting of mixtures of copper concentrate/dust, sulfur/dust, and pyrrhotite/dust. By the elemental chemical analysis of the mixture after and before the roasting process, the degree of arsenic volatilization was determined. The results indicated the effects of parameters such as roasting temperature, gas flow, gas composition, and the ratio of mixtures (concentrate/dust, sulfur/dust, or pyrrhotite/dust) on the volatilization of arsenic. According to the findings, the concentration of arsenic in the roasted Flash Smelting dust can be reduced to a relatively low level (<0.5 wt%), which allows its recirculation into an smelting process.

Electrostatic force of dust deposition originating from contact between particles and photovoltaic glass

Charged photovoltaic glass produces an electrostatic field.The electrostatic field exerts an electrostatic force on dust particles,thus making more dust particles deposited on the glass.In this paper,the contact electrification between the deposited dust particles and the photovoltaic glass is studied.Meanwhile,the surface charge density model of the photovoltaic glass and the electrostatic force of charged particles are analyzed.The results show that with the increasing of the particle impact speed and the inclination angle of the photovoltaic panel,the charges on particles increase to different degrees.Under a given condition,the electrostatic forces acting on the charged particles at different positions above the glass plate form a bell-shaped distribution at a macro level,and present a maximum value in the center of the plate.As the distance between the particle and the charged glass decreases,the electrostatic force exerted on the particle increases significantly and fluctuates greatly.However,its mean value is still higher than the force caused by gravity and the adhesion force,reported by some studies.Therefore,we suggest that photovoltaic glass panels used in the severe wind-sand environment should be made of an anti-static transparent material,which can lessen the dust particles accumulated on the panels.

Effect of photovoltaic panel electric field on the wind speed required for dust removal from the panels

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.

多组分表面活性剂复配对烟煤润湿效果研究

表面活性剂是1种溶于水且能显著降低溶液表面张力的物质,能有效解决煤矿井下采掘工作面粉尘危害问题。为研究多组分表面活性剂复配对烟煤润湿效果的影响,采用淮南潘三煤矿烟煤作为研究对象,以表面张力、沉降时间为考察指标,从8种表面活性剂中优选出阴离子表面活性剂快渗T、两性离子表面活性剂BS-12、非离子表面活性剂APG共3种试剂单体;通过比较表面张力和沉降时间,得出阴离子表面活性剂快渗T效果均为最好;同时采用分子模拟技术考察3种单体试剂的静电势分布,比较得出阴离子型表面活性剂快渗T的效果也是最好;采用正交试验法等比例复配,得到3种试剂单体最佳配方浓度分别为0.20%、0.15%、0.25%;此时表面张力为16.95 mN/m,比快渗T提高了30.59%;沉降时间为20.95 s,比快渗T提高了20.34%。

微米荷电颗粒在光滑玻璃表面沉积实验研究

为分析静电力对荷电月尘在光滑玻璃表面碰撞沉积过程中的影响,建立了荷电微米颗粒碰撞沉积实验系统;考虑极–板电压、颗粒粒径和玻璃试样倾角等影响因素,研究了2~13μm荷电颗粒的光滑玻璃表面沉积机制。实验结果表明:由于静电力作用,相同粒径颗粒的沉积量随极–板电压增大而增加;相同电压下颗粒的沉积量随粒径减小而逐步增大,平均粒径2.15μm的颗粒在14 kV电压荷电状态下,与0 V极−板电压下的沉积量相比增加了114%;相同粒径颗粒的沉积量在极–板电压小于6 kV时随玻璃试样倾角增大而减少;在30°~60°倾角范围内,45°玻璃试样荷电颗粒的沉积量增幅最大。研究结果可为航天探测器月尘防护设计提供参考。

HAMON电除尘器故障分析及应对措施

HAMON电除尘器可用于处理催化裂化烟气中的催化剂粉尘。由于催化裂化装置四年一修,电除尘器不能随时停运检修,因此针对HAMON电除尘器的运行情况进行研究,对于保障电除尘器及催化裂化装置的长周期稳定运行具有重要意义。在运行过程中,电除尘器出现电流和电压降低的问题。对故障原因进行分析,并在电除尘器停运后进行检查,发现:腐蚀泄漏导致电除尘器内部烟气湿度大。制定了检查、检修项目,更换了配件,同时结合冷态试验结果,调整了电除尘器的电流、电压、振打周期和振打力度。检修开工后,电除尘器入口粉尘质量浓度53.3 mg/m^(3),出口粉尘质量浓度4.8 mg/m^(3),远低于设计值(30 mg/m^(3))。检修开工至今超过2 a,电除尘器运行平稳,未出现任何故障,实现了长周期稳定运行。

输煤系统湿式电除尘器阴极线放电特性数值模拟

输煤环境中漂浮着大量微细粉尘,湿式电除尘器是去除10μm以下颗粒物的重要手段。本文建立了描述电除尘器放电(电势、电荷密度、电场强度等)、流场、粉尘运动的数学模型,数值模拟结果与Penney等人实验结果一致性较好。针对长×宽=650 mm×150 mm、3根阴极线直径为5 mm的放电系统进行了流场、放电及粉尘运动的数值模拟分析,通过所建立的数学模型,获得了较好分布的电势、电荷密度和电场强度,能够有效指导电除尘器的设计优化以提高除尘效率。

基于烧结机头粉尘特性理论的电除尘器灰斗结块燃烧研究

某钢厂烧结机机头电除尘器除尘灰灰斗发生了结块燃烧现象,影响了机头电除尘器运行。针对烧结机机头电除尘器除尘灰的粉尘特性进行研究,通过检测分析粉尘的含水量、成分、含碳量及粒径分布等,明晰烧结机头电除尘器灰斗结块燃烧原因,并提出基于烧结机头粉尘特性理论的电除尘器灰斗结块燃烧解决措施。研究表明:除尘器灰斗粉尘中水碳成分、碱金属氧化物以及微细粉尘占比较高,且一电场到三电场含量都呈现递增态势,从而导致除尘器灰斗中出现结块燃烧现象。由此提出烧结配料控制湿度6%~8%之间以及电除尘器灰斗增加声波吹灰器的结块燃烧解决措施,可为治理机头电除尘器除尘灰灰斗结块燃烧提供借鉴。

井下皮带机转运点除尘方案探析

基于井下皮带机转运点除尘方案,介绍一种转运点静电除尘装置设计结构。此静电除尘装置主要包括收尘电极、电晕线、振打清灰装置、高压电源、风机等结构,采用有限元仿真模拟方法,从除尘装置内流场、除尘装置内颗粒物轨迹以及皮带速度对气流的影响三个角度初步验证静电除尘装置的可行性,再采用工业性试验进一步确认静电除尘装置的应用价值,证明此除尘装置具有较好的皮带机转运点除尘效果。

凤台电厂双V型均流收尘电除尘技术提效改造试验

清洁高效先进节能的煤电是新能源体系的重要支撑,节能减排是火电厂今后的重点工作。对凤台电厂某660 MW机组电除尘器进行了性能测试分析,发现电除尘器出口A通道、B通道烟尘浓度偏高导致整体烟尘浓度偏高,电除尘器进口A通道、D通道流场不均匀,部分供电分区已退出工作,电除尘器出口烟尘平均质量浓度为81 mg/m^(3)超过了设计要求。在此背景下,开发了双V型均流收尘电除尘技术并进行了改造,对高压电源和烟道导流板进行了恢复性检修,改造后电除尘器出口粉尘浓度降至20 mg/m^(3)以下。对比试验得出:均流收尘电除尘技术具有显著的均流和收尘提效作用,可作为燃煤电厂老机组和非电领域电除尘器改造的选择方案。

基于科氏质量流量计的微米级煤尘和岩尘颗粒分类方法

【目的】岩尘的粒径比煤尘的小得多,更容易被吸入到肺中,危害较大。为了解决煤尘和岩尘混合颗粒的分类问题,提出一种微米级煤尘和岩尘混合颗粒的测量方法。【方法】首先采用环形静电传感器进行前端流体流量的测定,根据科氏质量流量计的测量原理,研究测量管两侧的时间差和流体的质量流量的关系;其次采用ANSYS有限元软件进行双向流固耦合,验证对煤尘和岩尘混合颗粒进行分类的可行性;最后对测量管进行静力学分析以及数值模拟分析,实现科氏质量流量计对微米级煤尘和岩尘混合颗粒的分类判别。【结果】在科氏质量流量计的同一个测量管道入口处,颗粒的流入速度与测量时间差正相关;谐振式U型管的激振频率应为二阶振型对应的固有频率113.11 Hz;当煤尘和岩尘颗粒混合粒径不同时,静力学参数和时间差随着煤尘的体积分数的增大而减小,并且全岩尘和全煤尘的时间差明显与混合颗粒的不同;当煤尘和岩尘混合颗粒粒径相同时,时间差随着煤尘的体积流量增大而增大,关系曲线的陡度也随着增大。当煤尘体积分数<50%时,煤尘和岩尘的混合颗粒的粒径越大时间差越大;当煤尘体积分数≥50%时,煤尘和岩尘的混合颗粒的粒径越大时间差越小。【结论】煤尘颗粒和岩尘颗粒具有鲜明且不同的分类判别特征,微米级煤尘和岩尘混合颗粒分类具有可行性,可实现科氏质量流量计对煤尘和岩尘混合颗粒的实时在线精确分类。

变流场电除尘与常规电除尘技术性能对比研究

通过对变流场电除尘技术与常规电除尘技术的本体结构特征、荷电粉尘在电场中的受力、有效收尘面积及电场风速进行分析,搭建了冷态物理试验中试平台,对变流场电除尘技术与常规电除尘技术进行了除尘性能试验。结果表明,变流场电场结构在增加总集尘面积、改变气体流向、降低电场风速的条件下,除尘性能没有得到突破,且除尘效率略有下降。从变流场格栅极板结构特性及电流密度角度分析了其除尘效率差的原因,同时提出了改进措施,以期提高变流场电除尘器运行效率,为电除尘器电场结构优化和设计提供参考。

燃煤焦化厂烟气脱硫吸收塔内过程优化及湿电除尘技术研究

为提高吸收塔脱硫效率,开展燃煤焦化厂烟气脱硫吸收塔内过程优化及湿电除尘技术的研究。选择某燃煤焦化厂内2×1 000 MW机组作为研究对象,建立燃煤焦化厂烟气脱硫喷淋塔几何结构模型,从反应区容积、喷淋浆液速度、喷淋负荷等多个角度分析烟气脱硫吸收塔的脱硫效率,得到结论:设置一三层、一二三层喷淋方式,且喷淋浆液速度为9 m/s,喷淋负荷在100%~160%之间,可以使燃煤焦化厂烟气吸收塔脱硫效果达到最佳。在此基础上,按照烟气预处理、电场荷电、湿式收集、连续清灰、排放与监控等步骤,进行湿电除尘技术的应用,实践证明此项技术的应用不仅能够高效去除烟气中的粉尘颗粒,达到环保标准的要求,还能够降低能耗、提高焦化厂的运行稳定性。

电袋复合除尘器在循环流化床锅炉的应用效果研究

为了解和提升电袋复合除尘器在循环流化床锅炉应用的减排效果,通过一定的筛选方法和调研参数的选取,本文对应用于10台不同规格循环流化床锅炉的电袋复合除尘器的运行情况进行调研统计及研究,并考察了电袋复合除尘器在某2×300 MW典型循环流化床锅炉机组上的运行情况。研究结果表明:10台电袋复合除尘器进口粉尘浓度为14.8~69.0 g/m^(3),出口粉尘浓度均低于10 mg/m^(3),其中3台低于5 mg/m^(3),占比30%,说明电袋复合除尘器对于进口粉尘浓度高或者低均适用;设备运行阻力最大值为1100 Pa,最小值为580 Pa,平均值为843 Pa,平均值均优于国家标准要求的运行阻力(≤1200 Pa)30%;滤袋使用寿命平均值为9.2 a,整体大幅优于设计使用寿命;通过对某2×300 MW典型循环流化床锅炉机组研究发现,该烟气工况具有烟温高、进口粉尘浓度高、粉尘高比电阻等特性,但仍然可以确保除尘器出口粉尘排放长期稳定保持在10 mg/m^(3)以下,除尘器运行控制在800 Pa以下。该电袋复合除尘器已稳定运行14 a,滤袋进行过一次更换,更换前滤袋使用寿命达10 a,是预期寿命2倍以上。电袋复合除尘器在循环流化床锅炉及除尘难度大的工况中具有良好的减排节能效果。

基于5G通信技术的静电除尘自动控制系统设计

在现代工业生产中,静电除尘技术使用高电压电场捕捉和去除排放气体中的微粒,从而减少工业排放对环境的影响。5G通信技术凭借其高速率、低延迟及广连接性等特点,为静电除尘系统的自动控制带来了革新的可能。文章重点探讨基于5G通信技术的静电除尘自动控制系统的设计与实现,详细介绍了该系统的架构、数据传输与监控机制以及性能评估,证实了5G通信技术能够提高静电除尘系统工作的效率和可靠性。通过实际测试验证了系统的实际应用效果,为今后静电除尘技术的发展与研究提供了一定的科学依据。

小单元气动振打电除尘技术研究及应用

双碳目标下,燃煤机组负荷适应性和提效改造正成为行业改造升级的主流方向。在此背景下,分析了电除尘出口槽型板粉尘逃逸原理,研发了小单元气动振打电除尘技术,通过对电除尘器出口槽型板进行小单元划分,并设置单独的振打清灰机制,实现了收尘功能,并解决了影响电除尘二次扬尘的技术瓶颈,显著提升了电除尘器的除尘效率。以江苏镇江电厂某630 MW机组电除尘器改造为例,对比了不同负荷下的性能,并在燃用难以静电除尘的劣质煤种情况下进行了试验。试验结果显示:电除尘提效成果显著。

湿式静电除尘器在生石灰消化废气治理中的应用研究

为了探索湿式静电除尘器在生石灰消化废气治理中的应用效果,本研究通过模拟生石灰消化过程产生的废气,以蜂窝状立式湿式静电除尘器为例,详细分析了湿式静电除尘技术在去除废气中的粉尘和有害气体方面的性能。实验系统测量了处理前后的粉尘浓度、有害气体含量,评估了除尘器处理效能的稳定性。结果表明,蜂窝状立式湿式静电除尘器能够显著降低废气中的粉尘浓度及有害气体含量,具有97%的高粉尘去除效率与90%的有害气体减排效率,并展现出优异的运行稳定性。研究结果为湿式静电除尘技术在工业废气治理领域的应用提供了有力的技术支持。

基于时空网格的高压开关柜环境治理技术研究

为解决高压开关柜整体密闭空间建模造成的受潮凝露和静电灰尘防治效果不佳的问题,提出了一种基于时空网格的高压开关柜环境治理方法。首先,通过八叉数结构划分高压开关柜结构室的时空网格。其次,通过对高压开关柜凝露、静电吸附灰尘成因及形成时间进行分析,建立高压开关柜的时空网格的演化形态。在此基础上,采用环境干燥空气除湿净化装置进行防凝露和静电吸附灰尘控制。最后,在高压开关柜模拟环境下进行验证,高压开关柜环境控制准确率为99.7%,验证了该方法的有效性。该方法能提升高压开关室环境控制准确率,提高高压开关柜环境治理水平。

Removal of adhesive dusts from flue gas using corona discharges with spraying water

Effective removal of adhesive and fine dusts from flue gas is very difficult. A new method of electrostatic precipitation of the corona discharges with spraying water(CDSW) was introduced. A new electrode configuration and the circulation spraying of water were employed in the method. The efficient electrostatic precipitation for adhesive and fine dusts can be accomplished without any drain water during a long operating period. The fundamental structure, discharge characteristics, mechanism of spraying and precipitation principle of the electrostatic precipitation using CDSW were described and analyzed. The V I characteristics, spraying state, supplying water quantity, influence of temperature and clean of the electrodes were researched in series experiments. The treating effects of circulating spraying using the corona plasma at the same time of electrostatic precipitation were investigated. The fundamental theories and experimental data were proposed, in order to effectively remove the adhesive dusts from flue gas using CDSW in practice.

Study on Selection of Dust Collectors for Large Capacity Thermal Power Units in High Altitude Areas

A dust collector is an important equipment in a thermal power plant,and reasonable selection of a dust collector is important for environmental protection in the power plant. Huaneng Xining Power Plant is located at an elevation of 2 360 m. Based on the characteristics of the high altitude area and their special requirements for dust collectors,the selection of dust collectors for the thermal power unit in the high altitude area was studied,and then two types of dust collectors( a rotary electrode electrostatic precipitator and electric-bag composite precipitator) for the thermal power unit were compared from the aspects of technological and economical feasibility. Finally,a proposal to select a suitable dust collector for the thermal power plant was put forward.