燃煤电站大流量烟气下飞灰细颗粒声波团聚实验研究

Experimental study on acoustic agglomeration of fine fly ash particles in flue gas with large flow in coal-fired power plant

以某燃煤电厂烟气流量20 000 m^3/h(标况下)的中试实验平台为对象,采用在烟道两侧布置声波发生器并联合喷雾增湿,对不同频率和声压级的声波细颗粒团聚效果进行了测试研究。测试结果表明:声波频率和声压级对团聚效果有较大影响,在声波频率为1 400~ 1 700 Hz时,烟气中PM2.5颗粒能获得较好的团聚效果;随着声压级(或者功率)的增大,团聚效率提高,特别是声压级大于140 dB后,团聚效果明显增大;声波联合喷雾增湿能进一步促进烟气中细颗粒团聚,提升电除尘器对于PM2.5或者PM1颗粒的脱除效果。该结论对提高大型燃煤电厂锅炉烟气中飞灰细颗粒团聚效果和除尘效率有重要的指导意义。

Taking the pilot test platform of a coal-fired power plant with flue gas flow of 20 000 m^3/h at standard temperature and pressure as research object, the sound wave generators were installed at both sides of the flue duct, and combining with spray humidification, the authors tested the effects of frequencies and sound pressure level on acoustic agglomeration of fine particles in fly ash. The results show that, the acoustic frequency and sound pressure level have a great influence on the agglomeration. When the acoustic wave frequency was 1 400- 1 700 Hz, a better agglomeration effect of PM2.5 in the flue gas could be obtained. As the sound pressure level (or power) increased, the agglomeration efficiency increased. Especially, this increase became significant when the intensity of sound was higher than 140 dB. The acoustic wave combined with spray humidification could further promote the agglomeration effect of fine particles in flue gas and enhance the removal effect of electrostatic precipitator on PM2.5 and PM1. The research results have important guiding significance for improving the agglomeration of fly ash fine particles and increasing dust removal efficiency.