摘要
随着国家对固定源颗粒物排放要求越来越严格,需对颗粒物在污染物控制系统中排放过程的物理、化学变化进行深入研究。基于半干法脱硫技术的某煤粉工业锅炉污染物控制系统,在系统沿程设置4个测点进行颗粒物等速采样,并通过称重、激光粒度仪、SEM-EDS及XRD等手段对颗粒物进行测试分析。结果表明,4个测点的颗粒物浓度分别为9.90 g/Nm^(3)、793.50 g/Nm^(3)、92.14 g/Nm^(3)和26.72 mg/Nm^(3)。烟气排放出口实测颗粒物浓度为16.84 mg/m^(3),实测含氧量为8.07%,折算成基准氧含量9%时布袋除尘器出口颗粒物排放浓度为12.69 mg/m^(3),满足工业锅炉排放要求。此半干法脱硫反应器进口的颗粒物主要由锅炉出口飞灰与增湿循环灰结合而成,粒径分布呈现出典型的双峰分布形态,峰值出现在0.7和22μm处,其中粒径小于1、1.0~2.5、2.5~10μm和大于10μm的分级浓度占比分别为2.38%、2.59%、16.47%和78.54%;经过脱硫反应器后,颗粒物的粒径分布峰值向大粒径方向迁移,分别出现在1和90μm处,其分级浓度占比波动不大;旋风分离器后,飞灰颗粒物的粒径分布峰值向小粒径方向迁移,分别出现在0.7和6μm处,飞灰颗粒物总浓度及分级浓度下降,其中大粒径颗粒物占比明显下降。4个测点的颗粒物无论从形态还是成分上都有所不同,锅炉出口飞灰颗粒物不规则结构偏多,且存在明显团聚现象,颗粒物粒径偏大,其组成成分与燃煤飞灰类似;脱硫反应器出口飞灰颗粒物较大不规则多孔块状结构明显减少,而不均匀规则球型结构物质含量增多,颗粒物表面附有细小不规则物质,元素含量中Si、S和Ca元素含量有所增加;经过XRD检测分析发现,脱硫前颗粒物主要组分为钙矾石、SiO_(2)和Ca(OH)_(2)等,与燃煤飞灰组分一致,脱硫后组分发生变化,主要组分为CaO、CaSO_(4)·2H_(2)O和SiO_(2)。
With more and more strict national requirements on the emission of fixed-source particulate matter,it is necessary to conduct in-depth study on the physical and chemical changes of the emission process of particulate matter in the pollutant control system.In this paper,a pollution control system of pulverized coal industrial boiler was designed based on semi-dry desulphurization technology,four measuring points were set along the system,and the particles were sampled at constant velocity,and the particulate matter was tested and analyzed by weighing,laser particle size meter,SEM-EDS and XRD.The results show that the particulate matter concentrations at the four sites are 9.90 g/Nm^(3),793.50 g/Nm^(3),92.14 g/Nm^(3)and 26.72 mg/Nm^(3),respectively.The measured concentration of particulate matter at the outlet of flue gas emission is 16.84 mg/m^(3),the measured oxygen content is 8.07%,and the emission concentration of particulate matter at the outlet of bag dust collector is 12.69 mg/m^(3)when the oxygen content is 9%,which can meet the emission requirements of industrial boiler.Particulate matter at the inlet of the semi-dry desulfurization reactor is mainly composed of boiler outlet fly ash and humidifying circulating ash.The particle size distribution shows a typical bimodal distribution pattern,with the peak value at 0.7μm and 22μm.The fraction of particle size less than 1,1.0-2.5,2.5-10μm and more than 10μm is 2.38%,2.59%,16.47%and 78.54%respectively;the particle size distribution peak value migrates to the large particle size direction after desulphurization reactor,which appears at 1μm and 90μm respectively,and the fraction of particle size varies little.After cyclone separator,the particle size distribution peak value of fly ash particles migrates to small particle size direction,which appears at 0.7μm and 6μm respectively.The total concentration and classification concentration of fly ash particles decrease,and the proportion of large particles decreases significantly.The particles of the four meas
作者
王建朋
段璐
纪任山
王志强
杨石
王乃继
WANG Jianpeng;DUAN Lu;JI Renshan;WANG Zhiqiang;YANG Shi;WANG Naiji(China Coal Research Institute,Beijing 100013,China;China Coal Research Institute Company of Energy Conservation,Beijing 100013,China;National Energy Technology&Equipment Laboratory of Coal Utilization and Emission Control,Beijing 100013,China)
出处
《洁净煤技术》
CAS
北大核心
2021年第3期241-247,共7页
Clean Coal Technology
基金
国家自然科学基金青年基金资助项目(51906095)
中国煤炭科工集团有限公司国际合作项目(2019-TD-2-CXY003)。
关键词
半干法脱硫
颗粒物
粒径分布
元素分析
semi-dry desulfurization
particulate matter
particle size distribution
ultimate analysis
