摘要
以镧钨和硝酸镧为原料,制备镧钨发射材料,研究其发射特性,并分析了镧钨阴极高温静电除尘器的除尘特性。研究表明,镧钨材料由La2WO6和W组成,逸出功2.88 eV。该材料的发射电流密度随温度和电压的升高而增大,温度对其影响显著。镧钨阴极热电子发射式高温静电除尘器荷电区离子密度可达1015～1016个/m3以上,比传统电晕式静电除尘器(ESP)的离子密度要高两个数量级以上。研究了烟气流速、荷电区电压以及粉尘粒径对除尘效率的影响。当粒径小于10μm时,除尘效率随着粉尘粒径的增大而提高很快。荷电区电压的增大提高了荷电区的离子密度,使得粉尘荷电量增加,从而提高了除尘效率。当流速超过1.2 m/s时,随着流速的增大,除尘效率迅速降低。
With Lanchanum-tungsten and lanthanum nitrate serving as the raw materials,prepared was the lanthanum-tungsten emission material.It has been found that the lanthanum-tungsten material is composed of La2WO6 and W,crystal particles are uniformly distributed and the escaping power needed is up to 2.88 eV.According to the experimental study of the emission characteristics,the emission current density of the material in question increased with an increase of the temperature and voltage and the former exercised a remarkable influence on the above-mentioned current density.The ion density in the charging zone of a lanthanum-tungsten cathode thermion emission type high-temperature static precipitator was more than 1015~1016 ions/m3,more than two magnitude orders higher than that of a traditional corona type electrostatic precipitator(ESP).The authors performed a study of the influence of the flue gas flow speed,voltage in the charging zone and dust particle diameter on the dust removal efficiency.When the particle diameter is below 10 μm,the dust removal efficiency will rapidly rise with an increase of the dust particle diameter.To increase the voltage in the charging zone can increase its ion density,leading to an increase of the charge number and thus improving the dust removal efficiency.When the flow speed is in excess of 1.2 m/s,the dust removal efficiency will quickly decline with an increase of the flow speed.
出处
《热能动力工程》
CAS
CSCD
北大核心
2011年第5期576-581,634,共6页
Journal of Engineering for Thermal Energy and Power
基金
国家自然科学基金资助项目(50778090)
关键词
镧钨阴极
热电子发射
静电除尘
lanthanum-tungsten cathode,thermion emission,electrostatic dust removal
