复合聚并协同脱除燃煤颗粒物及颗粒态重金属的中试研究

燃煤颗粒物和其上富集的As、Se、Pb等重金属排入大气后危害环境和人体健康。本研究开发以湍流聚并、壁面回流吸附为原理的复合聚并器，研究了聚并前后对颗粒物和颗粒态重金属的聚并效果。首先采用数值模拟方法综合考虑压力损失、速度均匀性和颗粒物聚并效果，优选了折叶片作为复合聚并器的叶片类型。随后进行了不同流量的颗粒物聚并中试研究，发现复合聚并器对PM₁的聚并率可达32.84%，随着流量从11.1 m/s增加到17.6 m/s，PM_2.5聚并率呈现一定下降趋势，说明了流量增加导致颗粒停留时间缩短和颗粒物聚并率的下降。通过对比聚并前后颗粒物中As、Se、Pb的浓度变化，发现聚并过程增强了对气态重金属的吸附，也会聚集富含重金属的纳米级颗粒物，从而造成PM₁中重金属浓度的增加。聚并后PM₁内的As、Se、Pb绝对浓度的降低，显示了复合聚并器对颗粒物和颗粒态重金属的协同脱除效果。

Effects of multiple agglomeration technology on the removal of particulate matters and particulate heavy metals: A pilot study

The emmision of particulate matters and heavy metals such as As, Se and Pb from coal combustion into the atmosphere would cause a serious environmental and human health hazard. Therefore, a multiple agglomeration based on the principle of turbulent coalescence and wall surface adsorption was developed to investigate the agglomeration effects on the removal of particulate matter and particulate heavy metals. Firstly, a numerical simulation method was adopted to comprehensively study the pressure loss, the velocity uniformity and the particle agglomeration effect, and a folded blade was selected for the multiple agglomeration device. Subsequently, a pilot study at a coal-fired plant on the particle agglomeration at different flue gas velocities was carried out. It is found that the agglomeration rate of PM₁ in the multiple agglomeration device is up to 32.84%. As the gas velocity is increased from 11.1 to 17.6 m/s, the agglomeration rate of PM_2.5 shows a certain decline, indicating that an increase in gas velocity would lead to a shorter residence time of particles and thus a decrease in agglomeration rate of particles. By comparing the concentration changes of As, Se and Pb in the particles before and after agglomeration, it is found that the agglomeration process can enhance the adsorption to gaseous heavy metals and also aggregate the nano-particles rich in heavy metals, thus resulting in an increase in the concentration of heavy metals in PM₁. The decrease of the absolute concentrations of As, Se and Pb in PM₁ after coalescence shows a cooperative removal effect in the multiple agglomeration device on the particulate matter and particulate heavy metals.