Contrastive analysis of reducing ultrafine particulate matters emission by two modified kaolin

doi:10.11949/j.issn.0438-1157.20151364

Abstract

Abstract:

Two kinds of typical modification methods, hydrochloric acid potassium manganate modification and sodium hydroxide modification are chosen. These modification methods may change the physical and chemical characteristics of kaolin by using the strong acidity and strong oxidizing of hydrochloric acid potassium manganate, and the strong basicity of sodium hydroxide. And these changes may improve the particulate matter (PM) captured efficiency of kaolin. A typical coal chose in the experiment burns with the raw and modified kaolin in an electrical heated drop-tube furnace, and the particle size distribution of particulate matter is obtained. According to the experimental results, the acid modification can significantly improve the capture efficiency of PM_0.2(particles with the aerodynamic diameter less than 0.2 μm) by kaolin, but the alkali modification inhibit the capture of PM_0.2. According to the characterization analysis, for the acid modification kaolin, the Al—OH bond, Al—O—Si bond, Si—O bond and Si—O—Si bond of kaolin are significantly weaken, which can promote the reaction between kaolin and alkali metals, and thus the capture efficiency of PM_0.2 is promoted. For the alkali modification kaolin, the Si—O bond and Si—O—Si bond of kaolin are weaken, but the Al—OH bond and Al—O—Si bond of kaolin are strengthened. The strengthened functional groups inhibit the sectional capture processes of alkali metals by kaolin, reducing the capture efficiency of PM_0.2.

Key words: coal combustion, ultrafine particulate matter, particle size distribution, adsorbents, kaolin, modification

摘要：

选用盐酸加锰酸钾改性和氢氧化钠改性两种典型的改性方法,期望利用盐酸和锰酸钾的强酸性和强氧化性、氢氧化钠的强碱性改变高岭土的物理化学特性,提高其捕获超细颗粒物的效率。选用典型煤种,将改性前、后的高岭土吸附剂混煤并送入高温沉降炉中燃烧,获得颗粒物的质量粒径分布。结果表明,酸改性能明显提高高岭土捕获PM_0.2(空气动力学直径小于0.2 μm)的效率,但碱改性效果相反。根据表征分析,酸改性明显削弱了Al—OH、Al—O—Si、Si—O和Si—O—Si四个官能团,促进了高岭土捕获碱金属的反应,提高了捕获PM_0.2的效率;而碱改性虽然削弱了Si—O和Si—O—Si两个官能团,但增强了Al—OH和Al—O—Si两个官能团,增强的官能团抑制了高岭土捕获碱金属的部分反应,导致高岭土捕获PM_0.2的效率降低。

关键词: 煤燃烧, 超细颗粒物, 粒度分布, 吸附剂, 高岭土, 改性

CLC Number:

X513

SUN Wei, LIU Xiaowei, XU Yishu, CHEN Dong, ZHANG Yu, CUI Jiang, XU Minghou. Contrastive analysis of reducing ultrafine particulate matters emission by two modified kaolin[J]. CIESC Journal, 2016, 67(4): 1179-1185.

孙伟, 刘小伟, 徐义书, 陈栋, 张宇, 崔江, 徐明厚. 两种改性高岭土减排超细颗粒物的对比分析[J]. 化工学报, 2016, 67(4): 1179-1185.

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