工业锅炉PM_(2.5)产排特性试验研究

Experiment study on production and emission characteristics of PM_(2.5) from industrial boilers

采用荷电低压颗粒撞击器(ELPI)对哈尔滨市两台燃用烟煤的工业锅炉PM2.5排放特性进行了研究.研究结果表明:PM2.5的粒数和质量浓度分布曲线均呈现单峰分布,前者峰值出现在0.12~0.2μm粒径范围内,这部分粒子主要是由无机物气化-凝结形成的亚微米颗粒物和挥发分未完全燃烧形成的炭黑粒子,而后者峰值出现在0.32μm处,粒子主要是由炭黑粒子形成的亚微米颗粒和残灰粒子形成的超微米颗粒.同时发现,旋风除尘和湿法除尘对PM2.5各级颗粒均有一定的去除效果,采用多管旋风和冲击水浴除尘器联合除尘效率比单种水膜除尘器除尘效率高;湿法脱硫系统对PM2.5的脱除也有明显的作用,由于除雾器不能全部去除小雾滴,这些雾滴中固体颗粒被干燥和水溶性物质结晶析出,PM0.32颗粒物粒数浓度有所增加,而PM0.32~2.5的颗粒物粒数浓度有所减少,但总质量浓度降低.

The emissions of PM 2. 5 in two bituminous coal-fired industrial boilers in Harbin were investigated by using Electric Low Pressure Impactor( ELPI). The results showed that the curves of particles number and mass size distributions of PM 2. 5 presented one single peak. The peak of the particles number appeared between 0. 12 μm and 0. 2 μm,mainly submicron particles formed by vaporization-condensation of mineral matter and soot particles transformed from unburnt volatiles. The peak for mass concentration appeared at 0. 32 μm,mainly submicron particles produced by soot and super-micron particles formed by residual ash particles. Meanwhile,it was found that cyclone and wet scrubber had a significant effect on the removal of PM 2. 5,and the removal efficiency of PM 2. 5 for cyclone and wet scrubber combined dust was higher than that for a single wet srcubber. The wet flue gas desulfurization( WFGD) system also decreased PM 2. 5 obviously. This was because the demister could not remove all the small droplets,a big number of solid particles and water-soluble substances in droplets were dried or crystallized,resulted in the number concentration of PM 0. 32 increased and the PM 0. 32 ~ 2. 5 reduced, with the total mass concentration also reduced.