化工学报 ›› 2017, Vol. 68 ›› Issue (11): 4261-4271.DOI: 10.11949/j.issn.0438-1157.20170345

• 能源和环境工程 • 上一篇    下一篇

湿法脱硫装置对燃煤锅炉PM2.5排放特征的影响

赵志锋, 杜谦, 董鹤鸣, 苏利鹏, 赵广播, 吕东辉, 王敏, 高建民, 郭馨, 徐力, 赵来福   

  1. 哈尔滨工业大学能源科学与工程学院, 黑龙江 哈尔滨 150001
  • 收稿日期:2017-04-05 修回日期:2017-08-22 出版日期:2017-11-05 发布日期:2017-11-05
  • 通讯作者: 杜谦
  • 基金资助:

    国家自然科学基金项目(jj20160337);国家环保公益性行业科研经费专项项目(201009006);国家科技支撑项目(2014BAA07B03);创新研究群体科学基金项目(51421063)。

Influence of wet flue gas desulfurization devices on PM2.5 emission characteristics of coal-fired boilers

ZHAO Zhifeng, DU Qian, DONG Heming, SU Lipeng, ZHAO Guangbo, LÜ Donghui, WANG Min, GAO Jianmin, GUO Xin, XU Li, ZHAO Laifu   

  1. School of Energy Science and Engineering, Harbin Institute of Technology, Harbin 150001, Heilongjiang, China
  • Received:2017-04-05 Revised:2017-08-22 Online:2017-11-05 Published:2017-11-05
  • Supported by:

    supported by the National Natural Science Foundation of China(jj20160337), Special Fund for National Environmental Protection Public Welfare Industries of China (201009006), the National Science and Technology Support Project (2014BAA07B03) and Science Foundation for Innovative Research Groups (51421063).

摘要:

采用二级稀释采样方法对1台电厂煤粉炉、1台电厂CFB锅炉和2台工业层燃炉配备的WFGD前后烟气中PM2.5进行现场采样。采用ELPI分析PM2.5的数量及质量浓度粒径分布;通过SEM分析PM2.5的显微结构,通过XRF、ICP-OES和离子色谱法分别对PM2.5中次量、痕量元素及水溶性离子含量进行测定。研究结果表明,相比于WFGD前,煤粉炉和CFB锅炉WFGD后PM2.5质量浓度减少,而层燃炉WFGD后PM2.5质量浓度增加。WFGD后PM2.5中存在大量块状、层状、片状、细小柱状和球形颗粒聚合体的结构,浆液成分及脱硫产物的附着会使PM2.5的外观形貌特征发生显著变化。脱硫后由于脱硫浆液的参与,PM2.5中Ca、S及相应Ca2+、SO42-含量显著增加,Si和Al的含量下降;气相的As、Se和Hg也会发生不同的化学变化从而进入PM2.5。湿法脱硫过程中浆液会捕集烟气中颗粒物,但脱硫浆液成分及脱硫产物会经由干化作用直接形成颗粒或与原有颗粒经碰撞聚合形成新颗粒。

关键词: WFGD, PM2.5, 粒径分布, 显微结构, 痕量元素

Abstract:

In this paper, a two-stage dilution sampling method was applied to collect PM2.5 in flue gas before and after the WFGDs in a utility pulverized coal boiler, a utility CFB boiler and an industrial grate-fired boiler, respectively. PSDs (particle size distributions) of PM2.5 number and mass concentrations were analyzed by ELPI (electrical low pressure impactor), microstructures of PM2.5 were analyzed by SEM (scanning electron microscopy), and the contents of minor and tract elements and water-soluble ions in PM2.5 were analyzed by XRF (X-ray fluorescence), ICP-OES (inductively coupled plasma optical emission spectroscopy) and IC (ion chromatography), respectively. The results showed that the mass concentrations of PM2.5 generated from the pulverized coal boiler and the CFB boiler after desulfurization were higher than those before desulfurization, but the mass concentrations of PM2.5 generated from the pulverized coal boiler and the CFB boiler after desulfurization were lower than those before desulfurization. There existed blocky, layered and finely columnar microstructures on the surfaces of PM2.5 after the WFGDs, and several particles belonging to PM2.5 were the agglomerates consisting of fine spherical particles. The attachment of the slurry composition and the desulfurization product will cause a significant change in the appearance of the PM2.5. After desulfurization, the contents of Ca, S and Ca2+ and SO42- in PM2.5 were significantly increased due to the participation of desulfurization slurry, while the contents of Si and Al decreased. The As, Se and Hg in the flue gas will also undergo different chemical changes to enter PM2.5. During the wet desulfurization process the slurry can trap particles in the flue gas, but the desulfurization slurry composition and desulfurization products will be dried to form particles or be collocated with the original particles to form new ones.

Key words: WFGD, PM2.5, particle size distribution, microstructure, trace elements

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