宽间距长芒刺静电除尘技术的应用

宽间距长芒刺静电除尘技术是国家“九五”科技攻关课题所取得的成果之一。由于采用宽间距、长芒刺放电极结构和极板涂敷特种防腐涂层 ,降低金属材料消耗的同时 ,降低了宽间距电除尘器电压工作范围 ,避免了使用超高压电源所致的绝缘难题 ,大大减少了静电除尘器的初期投资。笔者将该成果应用于某水泥厂生料磨系统 ,现场使用效果表明 ,该除尘技术不仅可有效改善作业环境 ,且工作电流、电压稳定 ,收尘效率高 ,设备阻力低 ,运转稳定可靠。     

双区电除尘器降低锅炉烟尘排放浓度

粉尘在传统结构的荷电区荷电之后,一部分尘粒被阳极板捕集,大部分带有正、负电荷的尘粒再分别被收尘区的管式辅助电极和阳极板捕集.模拟试验数据表明,收尘区具有高电压、低电流和板电流密度分布均匀的特性.工业性试验结果显示,应用双区电除尘技术设计或改造电除尘器,不仅可以较好地防止发生反电晕,而且能够将锅炉烟尘排放质量浓度降低到50 mg/m3以下.与传统的卧式电除尘器相比,还可节省10%左右的占地面积和钢材用量.     

Influence of wheat straw addition on composting of poultry manure

Poultry manure is a significant source of nitrogen, but small amount of carbon needs to be added for faster degradation of organic matter in composting process. Composting of poultry manure mixed with wheat straw was carried out in specially designed reactors (32 L) under controlled laboratory conditions over 13 days. The aim of the study was to determine the influence of wheat straw addition to poultry manure on performance of composting process in terms of the following: the substrate temperature, carbon dioxide, ammonia, pH, electrical conductivity and organic matter. According to the results, the mixture of 83% poultry manure and 17% wheat straw (dw) among three different mixtures used in this research provided the best conditions for composting process.     

The degradation of cyanide by anodic electrooxidation using different anode materials

Cyanides are very popular electrolytes used in metal electroplating, metal ore processing, chemical and electrochemical applications. Due to wide utility of these technologies cyanides become increasingly harmful effluent, which has to be treated. One of the best ways to degrade cyanides is an anodic electrooxidation. In this work the destruction of free cyanide on platinum, titanium and stainless steel (SS) electrodes has been investigated. It was determined that anode material greatly influences the process of cyanide electrooxidation. The best results were obtained by using the Pt electrode. This kind of anode allows us to reduce CN^? concentration from 0.1 M to 0.06 M during the first hour of electrolysis at a current density of 200 A m^?2, with a current efficiency up to 80%. To substitute expensive Pt anodes Ti electrodes covered with nanolayers of Pt were prepared and used for the anodic oxidation of cyanide ions. An effect of a thickness of Pt layer and temperature of an electrolyte solution were studied. It was established that using platinized Ti electrodes the current efficiencies of electrooxidation of cyanides of about 60% can be obtained. The usage of chloride ions to facilitate the destruction of cyanide was also studied.     

好氧堆肥反应器设计及实验研究

设计了具有气液固三相收集功能的强制通风自动搅拌好氧堆肥反应器,并对其进行了好氧堆肥性能试验,通过监测温度、p H、含水率、COD、BOD_5、重金属(Cu)、种子发芽率、热值等指标来判定堆肥效果。实验结果表明,反应器使堆肥周期大大缩短,COD、BOD_5及生物毒性降低明显,45 d后堆体基本腐熟且稳定,堆体减量30%,堆肥效果良好。独有的"耙形"搅拌有利于减少物料温度、湿度和氧气浓度的差异,加快了反应进程。底部二级过滤系统有利于改善渗滤液质量,方便渗滤液的收集及回灌。该反应器可为小型禽畜粪便堆肥反应器的研发和推广提供参考。     

输电线路山火跳闸机理的模拟实验研究

山火发生时植被燃烧产生的高温火焰及烟羽流使架空输电线路的空气绝缘性能大幅降低,可能引发导线之间或导线对地面间的击穿放电现象,导致输电线路发生跳闸事故。选取正庚烷与木垛为代表性火源,模拟研究直流高压电在火焰中的击穿放电现象,测量了火焰温度和电阻参数,获得了不同火源条件下放电间隙的击穿电压,分析了火焰参数对间隙击穿场强的影响。实验结果表明,正庚烷和木垛火焰放电实验中,火焰高温和电导率是导致击穿场强下降的主要因素。此外,烟颗粒也会导致击穿场强下降。     

Ti/SnO2-RuO2-Sb电极电氧化处理五氯苯酚模拟废水研究

采用刷涂-热解法制备了Sb、Ru掺杂的Ti/SnO2电极。通过SEM、EDX、XRD和循环伏安扫描(CV)表征了电极表面形态、组成、结构和电化学性质,并通过正交试验考察了电催化氧化降解五氯苯酚的影响因素。结果表明,各因素对五氯苯酚转化率影响的大小顺序依次为:底物初始质量浓度、反应温度、反应时间、电流密度、初始溶液pH值。在底物质量浓度为50mg.L-1,反应温度50℃,反应时间180min,电流密度40mA.cm-2,溶液初始pH值为8的条件下五氯苯酚的转化率达到97.6%。     

水平接地极泄散雷电流对临近埋地管道危害影响分析

为分析水平接地极泄散雷电流对临近埋地管道产生的暂态电磁干扰危害,通过EMTP软件建立水平接地极和埋地管道模型,考虑水平接地极与管道间的感性耦合和阻性耦合,采用多元回归分析法讨论土壤电阻率、水平接地极与管道间距、管道埋深、雷电流幅值等因素对管道防腐层感应电压的影响,最后讨论感应电流对管道腐蚀的影响。结果表明:离雷电流注入点越远,管道防腐层感应电流和感应电压幅值越低;感应电压受土壤电阻率、水平接地极与管道水平间距、管道埋深、雷电流幅值等因素影响明显,与土壤电阻率和雷电流幅值呈正相关,与管道埋深和水平接地极与管道水平间距呈负相关;土壤电阻率对管道腐蚀程度影响较大,土壤电阻率越低,管道腐蚀越严重;为保护防腐层和管道安全,水平接地极与管道间需保持一定安全距离。     

基于液电效应的高压电脉冲对煤体致裂实验研究*

为分析基于液电效应的高压电脉冲致裂煤体效果，采用电脉冲应力波实验和微观观测方法对潞安矿区煤样裂隙发展过程及其特征进行研究。结果表明:液电效应能明显致裂煤体，且作用次数越多，煤体裂隙密度越大、裂隙网络越贯通，同时煤体孔裂隙等结构薄弱部位的存在能促进裂隙的发育；液电效应对煤体作用可分为4个阶段，其中裂隙快速发展阶段是适合现场作用阶段；高压电脉冲通过液电效应产生冲击波和其他次生作用，且对煤体组成成分无影响；在现场应用中，应充分考虑煤体性质、钻孔布局等，采用“单点多次、多次连续、分段进行、全孔作业”的作业方式。该实验研究为基于液电效应的高压电脉冲技术应用提供支撑。     

The electrocoagulation/flotation study: The removal of heavy metals from the waste fountain solution

The objective of this study was to investigate the possibility of heavy metals (copper, zinc and nickel) removal from the waste fountain solution by the electrocoagulation/flotation (ECF) treatment. After the printing process, the fountain solution changes its composition due to direct contact with different printing materials (plates, inks, etc.) and becomes enriched with metals. The effect of operational parameters, such as electrode materials and combinations, current density, interelectrode distance and operating time, was studied. Also, response surface methodology (RSM) was applied to evaluate the effect of main operational variables and to get a balanced removal efficiency of metals from waste fountain solution by ECF treatment. The iron/iron electrode combination yields a higher percentage of copper and zinc removal efficiency (>95% and >80%, respectively), while for nickel the aluminum/iron and iron/aluminum electrode combinations (>95 and >85%, respectively) proved to be more successful. The optimum interelectrode distance was 1.0 cm (for copper) and 1.5 cm (for zinc and nickel) for all current densities. Heavy metal removal efficiency increases with the increase of electrolysis time for all electrode combinations. Also, the increase of current density improves the ECF removal efficiency. Based on the results obtained through RSM, the optimized parameters for the ECF waste fountain solution treatment for metal removal were identified as: Fe(−)/Al(+) electrode with interelectrode distance of 1.5 cm, operating time of 60 min and current density of 8 mA cm⁻². Overall, the ECF treatment was proven very efficient in the removal of heavy metals from the waste fountain solution under optimum conditions.     

Decolorization of synthetic Methyl Orange wastewater by electrocoagulation with periodic reversal of electrodes and optimization by RSM

Treatment of Methyl Orange (MO), an azo dye, synthetic wastewater by electrocoagulation with periodic reversal of the electrodes (PREC) was examined. Response Surface Methodology (RSM) was used to optimize the influence of experimental conditions for color removal (CR), energy consumption (ENC), electrode consumption (ELC) and sludge production (SP) per kg MO removed (kg(MO_r)) with optimal conditions being found to be pH 7.4, solution conductivity (к) 9.4 mS cm⁻¹, cell voltage (U) 4.4 V, current density (j) 185 mA cm⁻², electrocoagulation time (T) 14 min, cycle of periodic reversal of electrodes (t) 15 s, inter-electrode distance (d) 3.5 cm and initial MO concentration of 125 mg L⁻¹. Under these conditions, 97 ± 2% color was removed and ENC, ELC and SP were 44 ± 3 kWh kg(MO_r)⁻¹, 4.1 ± 0.2 kg(Al) kg(MO_r)⁻¹ and 17.2 ± 0.9 kg(sludge) kg(MO_r)⁻¹, respectively. With the enhanced electrochemical efficiency resulting from the periodic electrode reversal, the coefficients of increased resistance and decreased current density between the two electrodes in the PREC setup were 2.48 × 10⁻⁴ Ω cm⁻² min⁻¹ and 0.29 mA cm⁻² min⁻¹, respectively, as compared to 7.72 × 10⁻⁴ Ω cm⁻² min⁻¹ and 0.79 mA cm⁻² min⁻¹ as measured for the traditional electrocoagulation process. The rate constant of decolorization was also enhanced by 20.4% from 0.152 min⁻¹ in the traditional electrocoagulation process to 0.183 min⁻¹ in the PREC process. These performance characteristics indicate that the PREC approach may be more promising in terms of practical application, as a cost-effective treatment, than conventional electrocoagulation for textile dye removals.     

Enzyme Electrodes for Glucose Oxidation Prepared by Electropolymerization of Pyrrole

In this work, a method of fabricating enzyme electrodes with the potential application for biofuel cells and biosensors was investigated. Enzyme electrodes were prepared by entrapping native glucose oxidase (GOx) and ferrocene wired GOx (FeFcGOx), as the dopants, in conducting polypyrrole matrices by electropolymerization. Furthermore, the developed polymer enzyme layer was characterized by physical and electrochemical analysis, and glucose oxidation activity on both electrodes was studied. Both electrodes showed direct electrical communication between the enzyme and electrode surface. Low glucose oxidation current was observed from the electrode containing GOx. Higher glucose oxidation current was obtained with FeFcGOx, and the current increased with the escalating glucose concentration suggesting that efficient electron transfer between the enzyme and the electrode surface were achieved. A maximum sensitivity of 20 mM for glucose concentration was obtained for the polymer electrode prepared from FeFcGOx.     

电除尘器对烧结灰除尘性能影响的试验研究

在电场断面面积为0.3 m 2(600m× 500 m)的电除尘器(ESP)实验系统上,采用正交试验法,确定电晕线型式、含尘浓度、电压值和风量(电场风速)4个试验因子,总除尘效率为指标值,进行电除尘器对烧结灰除尘性能的试验研究.研究结果表明,当气流含尘浓度从15g/m3提高到25g/m3时,ESP的总除尘效率η从96.87%降至87.55%;当电源电压值由85 kV增至96 kV后,ESP的总除尘效率从98.16%降至87.55%;当ESP的电场风速由0.62 m/s增至0.79 m/s,总除尘效率由96.87%降至92.46%;星型线ESP的除尘效率相对较低;尖端放电可改善ESP用于高比电阻粉尘时的操作性能,芒刺线、锯齿线ESP的除尘效率分别高达99.46%和99.55%.     

Determination of explosion parameters of methane-air mixtures in the chamber of 40 dm3 at normal and elevated temperature

The experimental results of the measurements of the explosion pressure and rate of explosion pressure rise as a function of molar methane concentration in the mixture with air in the 40 dm³ explosion chamber are presented. The research was aimed at determination of the explosion limits, according to the EU Standard. The influence of initial temperature of the mixture (changing in the range of 293–473 K) on the fundamental explosion parameters was also investigated. The ignition source was an induction electrical spark of the power equal to approximately 10 W. It was stated, that the increase of initial temperature of the methane-air mixture causes a significant increase of the explosion range.     

带电细水雾的灭火实验研究

利用静电感应原理,设计了使细水雾强制带电的感应荷电装置,进行了带电细水雾的灭火实验研究。为研究带电细水雾的灭火效率,在受限空间内,采用小尺度实验方法,通过改变电压的极性和大小、针-环状电极的半径及其距伞罩电极之间的距离,分析对灭火时间和热电偶温度变化的影响。结果表明:带电细水雾比普通细水雾能更迅速地降低火焰温度、熄灭火焰,荷负电的细水雾比荷正电的细水雾具有更好的抑制效果,随着电压的增大、针-环状电极半径及两电极间距的减小,灭火效能提高,熄灭时间减少。     

超音速气动液滴荷电雾化及降尘性能试验研究*

为探究煤炭生产过程中呼吸性粉尘难以捕捉且对人体造成伤害的问题,提出超音速水雾荷电降尘技术。基于荷电雾化机理,研究电极环直径、电极间距、电压3因素对超音速气动液滴荷电、雾化效果的影响。利用网状目标法测量雾滴群电流并计算荷质比,采用SPSS软件分析3因素与雾滴荷质比之间的相关性,并用激光粒度仪测量雾滴粒径。最后,采用最优荷电雾化参数进行喷雾降尘试验。研究结果表明:各因素对荷电效果的影响次序为:电压>电极间距>电极环直径;雾滴粒径随电压的升高而减小,随电极间距的增大先增大后减小,随电极环直径的增大先减小后增大;当电压12 kV,电极间距2.5 cm,电极环直径6 cm时,超音速荷电水雾降尘效果最佳,与普通水雾降尘相比,全尘降尘效率提高12.4%,呼尘降尘效率提高49.6%。     

喷射电极静电除尘理论研究

根据当前国内外电除尘器的发展现状和电极结构特点,以改进电除尘器的电极结构和含尘气流的流动方式作为突破口,提出了具有喷射电极结构的静电除尘器.在喷射口周围布置有毛刷钢针芒刺放电极,电晕钢针将在高压电源作用下产生电晕放电.因此,当粉尘随含尘气流从喷口流出时,被电晕荷电.荷电粉尘在气流和电场力的作用下冲向收尘极板,被收尘极板捕集.     

Friction spark generation and incendivity of several metal alloys

When metal alloys are used as mechanical equipment or tools in explosive atmospheres, the occurrence and incendivity of mechanically generated sparks as ignition sources should be taken into consideration. The formation of mechanically generated sparks was investigated for seven metals, including Q235 steel, 304 stainless steel, TC4 titanium alloy, 6061 aluminum alloy, H62 bronze alloy, AMAK3 zinc alloy, and AZ31B magnesium alloy. The relationship between the physical-chemical properties and generation and incendivity of friction sparks was evaluated. For 6061 aluminum alloy, H62 bronze alloy, AMAK3 zinc alloy, and AZ31B magnesium alloy, no bright friction sparks were observed in the maximum friction velocity of 12 m/s and maximum surface pressure of 3.75 N/mm², because of low hardness, high thermal conductivity, low melting point, and the absence of carbon content. Ignition testing indicated that nano titanium dust layers with MIEL (minimum ignition energy of dust layer) of 1 mJ were not ignited by friction particles from the four metal alloys. However, bright particles were clearly observed for 304 stainless steel, Q235 steel, and TC4 titanium alloy. Friction sparks at the maximum power densities showed incendivity with micro titanium layers having an MIEL of 17.5–25 mJ but not with PMMA, corn starch, and wood dust having MIELs greater than 1 J. Two different particle burning behaviors with different fragmentation mechanisms during the friction process were determined, namely the micro explosion phenomenon for TC4 titanium alloy and particle burst for Q235 steel. Results indicate that the physical-chemical properties of friction metal rods are useful for preliminary evaluation of spark generation. Powder layers with known MIEL can be considered as indicator testing materials to evaluate spark incendivity.     

电源频率对大气压氦气射流等离子体放电特性的影响

为探究大气压射流等离子体放电特性,利用同轴双环电极结构等离子体射流装置,研究电源频率、外加电压对氦气射流放电电流、起始电压、消耗功率、放电平均功率、射流长度等参数的影响规律。结果表明:放电图像在f=7.88,8.40,8.90 kHz电源频率下,随着电压增加,等离子体射流长度先增长后稳定;电压-电流关系符合辉光放电特征;同一电源频率下,随外加电压升高,放电电流脉冲个数增多、幅值增大、脉冲曲线产生畸变,装置消耗功率和放电功率所受影响不大。     

陆上油气管道受高压直流接地极干扰的腐蚀与防护实例分析

高压直流接地极放电时会对附近的管道产生强烈的电干扰,导致管道腐蚀加速,为了预测高压直流接地极对埋地管道的干扰程度并及时筛选合适腐蚀防护措施,利用数值模拟技术计算高压直流干扰下管道的干扰电位以及管体腐蚀速率,并结合相关标准对干扰水平进行评估。在此基础上,研究“单独管道方采取措施”、“管道方和电力方均采取措施”、“电力接地极更换极址”3种方案下的腐蚀防护效果。研究结果表明:对当前极址来说,需要管道方安装大量措施同时电力方对放电电流进行控制才能达到目标;而高压直流接地极极址土壤电阻率较低的情况下可以大幅降低对附近管道的干扰水平;就本文所列工程案例来说,更换极址是比较经济的方案。