电除尘器斜气流状态下粉尘沉降试验研究

针对电除尘器在实际运行过程中出现的除尘效率下降问题,提出斜气流这一新型技术,对均匀气流与斜气流分布状态进行可视化研究;在两种气流状态下进行粉尘沉降试验,对试验结果进行对比分析、总结相应规律;对我国电除尘器气流技术的发展提出了建议。     

矿山粉尘分布及扩散规律研究进展

对采矿粉尘分布及扩散规律的实验研究和数值模拟研究进展进行综述,研究表明实验结果与模拟结果基本一致,但是模拟可以给出更加详尽的粉尘浓度、分布和扩散规律数据,为有针对性地采取防尘措施、选择除尘技术提供科学的理论依据,并对今后的发展方向进行了展望。     

锅炉电除尘器飞灰粒径分布特性试验研究

对５台锅炉４种型号的电除尘器进行飞灰粒径分布特性试验研究，结果表明：电除尘器飞灰粒径分布特性服从概率统计定义的分布函数，即威布尔分布。研究得出了电除尘器飞灰分布特性函数α和β数值及变化规律，电除尘器分级除尘效率特性参数ｎ和ｍ的数值及变化规律，所提供的试验数据可作为在役机组电除尘器改造，新建机组电除尘器选型的依据。     

粉尘比电阻对电除尘的影响及改进措施研究

着重研究、了影响电除尘器效率较为突出的因素——粉尘比电阻,总结出：针对高比电阻粉尘对电除尘器的影响,必须定期测试粉尘的比电阻并对烟气进行调质,还可采取间歇供电的方式来提高除尘效率;对低比电阻粉尘．可直接敲打或刷落收尘极板上的粉尘,或采用高电阻率收尘极板及用导电涂料涂敷收尘极板等方法均可以提高除尘效率。     

电除尘过程数学模型的研究

电除尘运行过程中随机干扰因素很多，本文从影响电除尘器性能的诸多因素中，抓住主要矛盾，找出了影响除尘过程的可测可控的运行参数，建立了除尘过程数学模型，为分析电除尘器过程控制对象特性，进行了电除尘过程多变量功率控制仿真，为实现优化控制打下了良好的基础。     

移动电极电除尘器除尘效率的计算

移动电极静电除尘器通过清灰刷除掉阳极板上收集的粉尘,阳极系统为移动电极（即作回转运动的集尘极）阳极板呈带条状,固定在链条上,随链轮转动。移动电极静电除尘器有效克服了困扰常规电除尘器对高比电阻粉尘的反电晕及振打二次扬尘等问题,大幅度提高了除尘效率。提供常规固定电极除尘区与移动电极除尘区联合使用的除尘器除尘效率计算公式。     

电除尘器前端预荷电技术研究

电除尘器前端主要是指进口喇叭及进气烟道,在进口喇叭内设置预荷电电场,可以保证气流均匀进入电场的同时,对粉尘进行荷电、凝并,起到一级预收尘的作用,以增加收尘面积,提高除尘器的除尘效率。通过分析Indigo烟道凝聚器、进口喇叭内置电场技术、电除尘器中粉尘预荷电试验研究及国内专利技术成果基础上,提出电除尘器进口喇叭内预置电场技术,并取得比较好的应用效果。     

燃煤机组静电除尘器的运行状况分析与优化

分析了我国现有燃煤机组静电除尘器的运行情况,研究了静电除尘器的造价、运行成本、出口粉尘含量等各方面情况,进而分析了除尘器入口粉尘含量、漏风率、二次电压、运行温度和湿度对除尘效率的影响.结果表明,除尘器入口粉尘含量和漏风率的增加不利于除尘器的运行,而二次电压和湿度在一定范围内增大有利于除尘效率的提高,电除尘器只能在一定温度区间能达到高效运行.提出相应的优化措施,为电除尘器技术改造提供参考.     

粉尘对电除尘器电场影响的初步探讨

本文从理论上探讨粉尘对电除尘器电场分布和运行性能的影响,提出了在已知空载伏-安特性的情况下求取负载伏-安特性的数学模型。计算结果表明粉尘电荷使电场分布发生改交,电流下降,在极端情况下发生电晕闭塞。     

电除尘脉冲供电及其改善除尘效果的分析

本文从电除尘器粉尘层的电容性出发,讨论了电除尘器常规电源供电和脉冲电源供电时的电气特性,分析了脉冲供电改善除尘效果的原因,并对脉冲供电的应用提出了一些看法。     

超细颗粒物凝聚中试试验均匀给料方案研究

给料的均匀性对PM2.5团聚试验至关重要,运用数值方法,采用LES模型计算湍流流场,采用DPM模型计算颗粒运动轨迹,分析PM2.5团聚中试试验台烟道内加设钝体后颗粒的均匀分布,得到了水平烟道各截面处颗粒浓度分布及数值的均方差曲线,发现在试验台圆方管处加设钝体,能有效改善烟道内煤灰颗粒的均匀分布。     

Waste tyre pyrolysis: Modelling of a moving bed reactor

This paper describes the development of a new model for waste tyre pyrolysis in a moving bed reactor. This model comprises three different sub-models: a kinetic sub-model that predicts solid conversion in terms of reaction time and temperature, a heat transfer sub-model that calculates the temperature profile inside the particle and the energy flux from the surroundings to the tyre particles and, finally, a hydrodynamic model that predicts the solid flow pattern inside the reactor. These three sub-models have been integrated in order to develop a comprehensive reactor model. Experimental results were obtained in a continuous moving bed reactor and used to validate model predictions, with good approximation achieved between the experimental and simulated results. In addition, a parametric study of the model was carried out, which showed that tyre particle heating is clearly faster than average particle residence time inside the reactor. Therefore, this fast particle heating together with fast reaction kinetics enables total solid conversion to be achieved in this system in accordance with the predictive model.     

三维电极法处理含钴、锰废水

采用三维电极法对工业精对苯二甲酸(PTA)装置产生的含钴、锰废水进行处理.通过与传统二维电极法的处理效果进行比较,论证了三维电极法脱除Co2+,Mn2+的优越性.探究了填料类型、极板间电压、粒子电极填充比(粒子电极质量(g)与废水体积(mL)的比)、极板间距等工艺参数对Co2+,Mn2+脱除率的影响.实验结果表明,适宜...     

MEEP清灰钢刷失效分析与试验装置设计

移动电极电除尘器（MEEP）具有出口粉尘排放浓度低、可有效收集PM2.5等优点,其运动部件的可靠性越发受到国内外制造厂家的重视,清灰钢刷作为其关键部件之一,其国产化后的寿命和失效形式的研究越来越重要。分析了钢刷结构失效形式,并在综述了国外移动电极电除尘器钢碡4的研究经验的基础上,设计了钢刷失效形式和寿命测试试验装置。为提高钢刷寿命和降低移动电极电除尘器出口粉尘排放浓度提供了试验数据,推动了移动电极电除尘器关键的运动部件的研究进程,为移动电极电除尘器钢刷的改进和现有设备间距时间调整提供参考。     

Model calibration and validation for OFMSW and sewage sludge co-digestion reactors

A mathematical model has recently been proposed by the authors to simulate the biochemical processes that prevail in a co-digestion reactor fed with sewage sludge and the organic fraction of municipal solid waste. This model is based on the Anaerobic Digestion Model no. 1 of the International Water Association, which has been extended to include the co-digestion processes, using surface-based kinetics to model the organic waste disintegration and conversion to carbohydrates, proteins and lipids. When organic waste solids are present in the reactor influent, the disintegration process is the rate-limiting step of the overall co-digestion process. The main advantage of the proposed modeling approach is that the kinetic constant of such a process does not depend on the waste particle size distribution (PSD) and rather depends only on the nature and composition of the waste particles. The model calibration aimed to assess the kinetic constant of the disintegration process can therefore be conducted using organic waste samples of any PSD, and the resulting value will be suitable for all the organic wastes of the same nature as the investigated samples, independently of their PSD. This assumption was proven in this study by biomethane potential experiments that were conducted on organic waste samples with different particle sizes. The results of these experiments were used to calibrate and validate the mathematical model, resulting in a good agreement between the simulated and observed data for any investigated particle size of the solid waste. This study confirms the strength of the proposed model and calibration procedure, which can thus be used to assess the treatment efficiency and predict the methane production of full-scale digesters.     

Application of Dispersion Modelling for Analysis of Particle Pollution Sources in a Street Canyon

The dominating source of particles in urban air is road traffic. In terms of number concentration, its main contribution is within the range of ultrafine particles (Dp < 100 nm). The dispersion conditions, i.e. transport and dilution, of the submicrometer particles are expected to be like for gases and therefore the particle concentrations in a street canyon can be calculated using gaseous pollutants dispersion models. Such processes, like coagulation or condensation, are less important due to the short residence time within the street canyon environment.Two extensive measuring campaigns were conducted in the street Jagtvej in Copenhagen, Denmark. The particle size distributions were measured by a Differential Mobility Analyser (DMA) coupled to a particle counter, providing high time resolution data (1/2 hourly) on a continuous basis. Measurements of NO_x, CO and meteorological parameters were also available. The measured particle number concentrations, especially below 100 nm, reveal very similar dependence on the meteorological conditions as the NO_x concentrations. This underpins the conclusion that dilution properties are similar for particles and NO_x. For particle sizes over 100 nm, somewhat different behaviour is observed. This points toward existence of additional particle sources, not related to traffic emissions within the street canyon. A significant contribution is believed here to be attributed to long-range transport. The total particle emission from traffic, including daily variation and size distribution, has been calculated using the OSPM dispersion model. Results are in accordance with a previous analysis based on statistical modelling.     

凝聚器在提高电除尘效率上的试验研究

细微颗粒物的污染日益受到广泛关注,而常规静电除尘器对微细颗粒物的去除并不是很显著。采用双极荷电凝聚技术对静电除尘器加装凝聚器,并进行中试试验。结果表明,凝聚器凝聚效果明显,不仅有利于除尘效率的提高,更有利于减少细微颗粒物的排放,具有非常重要的工业应用价值。     

适应低排放的电除尘技术探讨

针对高标准的排放要求以及将进一步提高的排放标准,对电除尘器是否能满足目前的排放标准和低排放要求进行了研究。通过对国内110个机组配套电除尘器实际应用情况调查和国外燃煤机组电除尘器应用分析,客观地评价了电除尘器对国内煤种的适应性,指出移动电极式电除尘器、双极异距电流体微粒聚合器、烟气调质、湿式电除尘器、低低温电除尘器等新技术的发展和综合应用是满足30mg/m3低排放标要求的最佳选择。     

LNE-CFD数值模拟技术的研究与应用

采用从微观到宏观的多尺度方法,对电除尘器的关键部件进行了深入研究,成功开发出一种新的电除尘器数值模拟技术LNE-CFD。应用结果表明,对于现有结构及布置方式的电除尘器,LNE-CFD模拟结果准确,可代替物模试验。LNE-CFD模拟技术对电除尘器的优化设计和机理研究具有重要意义。     

Mathematical modelling of MSW incineration on a travelling bed

The rising popularity of incineration of municipal solid waste (MSW) calls for detailed mathematical modelling and understanding of the incineration process. In this paper, governing equations for mass, momentum and heat transfer for both solid and gaseous phases in a moving bed in a solid-waste incineration furnace are described and relevant sub-models are presented. The burning rates of volatile hydrocarbons in the moving bed of solids are limited not only by the reaction kinetics but also the mixing of the volatile fuels with the under-fire air. The mixing rate is averaged across a computation cell and correlated to a number of parameters including local void fraction of the bed, gas velocity and a length scale comparable to the particle size in the bed. A correlation equation is also included to calculate the mixing in the freeboard area immediately next to the bed surface. A small-scale fixed bed waste incinerator was built and test runs were made in which total mass loss from the bed, temperature and gas composition at different locations along the bed height were measured. A 2-D bed-modelling program (FLIC) was developed which incorporates the various sub-process models and solves the governing equations for both gases and solids. Thermal and chemical processes are mainly confined within a layer about 5-9 times in thickness of the averaged particle size in the burning bed. For a large part of the burning process, the total mass loss rate was constant until the solid waste was totally dried out and a period of highly rising CO emission followed. The maximum bed temperature was around 1200 K. The whole burning process ended within 60 min. Big fluctuations in species concentration were observed due to channelling and subsequent 'catastrophic' changes in the local bed conditions. Reasonably good agreement between modelling and measurements has been achieved. Yet the modelling work is complicated by the channelling phenomenon in the bed. Numerical simulations without consideration of the channelling effect produced very good agreement with experiments concerning the total mass loss, but significant discrepancy exists for temperature and gas composition profiles. Transient phenomena such as the breaking of waste particles and the "catastrophic" creation of new burning channels occurring during waste incineration is a vital area requiring further investigation at the fundamental level. The underlying theory of bed behaviour must be extended to include these transient events.