【作者】 杨丁；

【导师】 黄学敏； 党小庆；

【作者基本信息】 西安建筑科技大学 ， 环境工程， 2006， 硕士

【摘要】 我国燃煤发电锅炉约90%左右采用电除尘器,要求烟尘允许排放浓度从200mg/Nm~3降到50mg/Nm~3(GB13223-2003),需进一步提高电除尘器的性能、降低烟尘的排放浓度。电除尘器的电场制约电晕产生、粒子荷电以及荷电粒子在电场中的迁移,是决定电除尘器运行性能的主要因素。 电除尘器电场的研究有实验与数值两种手段。本文选择火电厂电除尘器常用的4种电晕线与ZT24型阳极板,测量了同极距300mm,350mm,400mm和450mm的Ⅴ-Ⅰ特性、板面电流密度大小和分布,分析了电极配置参数对Ⅴ-Ⅰ特性和极板表面电流密度大小和分布的影响。采用表征电流密度大小的平均电流密度j和表征分布均匀性的方差σ作为电场特性的评价指标,给出了电场特性参数较好的电极配置形式和参数调整范围。 数值计算有助于深入了解电场特性随电极配置参数变化的规律。本文用圆筒形电极解析解和数值解相对比,验证有限元法求解电除尘器电场的可靠性。采用有限元法对V型线与ZT24型阳极板匹配的各种形式进行求解,将数值计算所得电晕区场强和电晕外区场强与实验所测板面电流密度进行对比分析,讨论电场特性参数优劣的原因。更多还原

【Abstract】 In our country, about 90% electrostatic precipitators are employed tor collecting tly ash in coal-fired power plants. The new allowed particulates emission for new coal-fired power plants is 50 mg/m~3 (standard), so it is required to improve the performance of electrostatic precipitator and reduce the emission concentration of fly ash. Corona generation, particle charging and particle collection are determined by electric field.In this paper, four kinds of discharge electrodes which are usually used in electrostatic precipitator of coal-fired power plants are choused. By measured the V-I characteristic and the current density on the collecting plate on the condition of 300mm / 350mm/400mm/450mm collecting electrode spacing, Analyzed the different parameters of combinations which influence the V-I characteristic and the current density on thecollecting plate. Used the average current density j and distribution relatively deviationσ to discuss the effect of different discharge electrodes and setting manner;Give several kinds of better electrical field of different combination and the range of parameter adjustment.The numerical method can help deeply study the law of electric field characteristic which changed with parameters of combinations. In this paper, testify reliability of FEM in wire-cylinder electrostatic precipitator by comparing the parsing value and numerical value.Compute space distribution of voltage and field intensity of wire-plate by finite element method, conclude two factor which determine the current density,one is the field intensity inside region of corona glow,another is the field intensity outside region of corona glow. Discuss the cause of the better electrical field.更多还原