煤粉炉掺烧干化污泥的污染物排放研究

结合某电厂420 t/h四角煤粉炉掺烧污泥项目的实验室分析测试,了解煤粉掺烧不同含水率不同比例的干化污泥条件下烟气中污染物和灰渣中重金属的排放特性.结果表明,在实验研究配比和燃烧的条件下,大部分重金属元素Pb、Cu、Cr和Ni残留在灰渣中,Zn、Cd部分残留在灰渣中, As、Hg和Se等易挥发元素释放到烟气中,在灰渣中的含量很小.掺烧污泥后,灰渣中的重金属含量较单烧单煤都有了一定幅度的升高,Zn的含量是单煤的2倍,其余重金属是单煤的1.1~1.2倍.3种不同的掺混比例之间的污染气体排放浓度基本相似.烟气中主要污染物及重金属浓度可以满足现行国家标准.与单烧单煤相比,CO、HCl以及其他有机气体排放浓度基本相同;NH3的排放浓度较单煤有所升高;SO2、NOx和CO2排放浓度略有降低;飞灰浓度有所升高.烟气中的重金属,Hg含量升高了30%,Pb含量约为单煤的4.3~4.8倍.以上研究结果可为环保达标和飞灰利用提供基础数据.

Research on pollutants emitted from dried sludge blending combustion in coal-powder boiler

Through lab test and analysis of coal-sludge blending combustion in 420 t/h tangentially coal-fired boiler of a power plant, this paper demonstrates the emission performance of pollutions in the flue gas and heavy metal in the ash in the cases of coal blending combustion of dried sludge of different water contents and proportions. The results show that in the ratio and combustion conditions required by lab research, most of the heavy metal elements such as Pb, Cu, Cr, Ni and part of Zn, Cd remain in the ash while volatile elements such as As, Hg and Se are emitted into the flue gas with little remained in the ash. In the case of sludge blending combustion, all heavy metal elements in the ash increase compared with combustion of single coal. The content of Zn is 2 times and the other heavy metals are 1.1~1.2 times of single coal combustion. Emission concentrations of gaseous pollutants are basically the same with different blending ratios. The main pollutants and heavy metal concentration in the flue gas can meet the requirements of the current national standard. Compared with single coal combustion, concentrations of CO, HCl and other organic gases in the pollutants are basically the same; concentration of NH3 emitted increases; concentration of SO2, NOx, and CO2 decrease slightly; flying ash concentration increases. Regarding heavy metal in the smoke, Hg content increases by 30%, Pb content is about 4.3~4.8 times of that with single coal combustion. The research results above provide basic data for work on environmental compliance and the utilization of flying ash.