Mercury emission and speciation distribution under oxy coal combustion in fluidized bed

doi:10.16085/j.issn.1000-6613.2016.10.049

Abstract

Abstract: A study on the transformation of mercury speciation during oxy-coal combustion in fluidized bed was conducted. Two selected coal samples were Xuzhou bituminous coal and Huaibei bituminous coal. The effects of temperature and different types of coal on mercury emission during the air-coal combustion,as well as different types of coals on mercury speciation during the oxy-coal combustion were experimentally investigated. The results indicated that higher temperature promoted mercury oxidation and the sulfur content in the coal had an effect on the mercury oxidation during air-coal combustion. During oxy-coal combustion,the concentration of total gaseous mercury[Hg^T(g)] with Xuzhou bituminous coal was higher than that with Huaibei bituminous coal. Moreover,the percentage of Hg²⁺(g) to Hg^T(g) with Xuzhou bituminous coal was 16% higher than that with Huaibei bituminous coal,resulting from much higher sulfur content in Xuzhou bituminous coal. The percentage of Hg²⁺(g) to Hg^T(g) under oxy atmosphere was lower than that under air atmosphere with Xuzhou bituminous coal. While the percentage of Hg²⁺(g) to Hg^T(g) under oxy atmosphere was higher than that under air atmosphere with Huaibei bituminous coal,which could be due to the different sulfur contents in the two kinds of coals.

Key words: mercury oxidation, oxy fuel, fluidized bed combustion

摘要： 目前有关于富氧气氛下流化床燃烧汞的形态转化特性的报道还不是很多，因此本文开展了富氧气氛下煤种对汞形态转化特性的影响的实验研究。采用流化床作为实验设备，选用徐州烟煤和淮北烟煤作为实验燃料，研究了空气气氛下不同温度和不同煤种对汞析出规律的影响，富氧气氛下煤种对汞形态转化规律的影响，并深入分析了相应的汞氧化机理。研究结果表明：在空气气氛下，温度的增加会促进汞的氧化，煤中的含硫量对汞的氧化也有影响；在富氧气氛下，徐州烟煤燃烧产生的气态总汞浓度高于淮北烟煤燃烧产生的气态总汞浓度，徐州烟煤的Hg²⁺（g）的分布率也比淮北烟煤的Hg²⁺（g）的分布率高出16%左右，因为徐州烟煤中高含硫量会影响Hg²⁺（g）的分布率；富氧气氛下徐州烟煤的Hg²⁺的分布率低于空气气氛下的，而淮北烟煤的Hg²⁺（g）分布率则与之相反，这与两种煤中硫含量的不同有关。

关键词: 燃煤汞形态, 富氧, 流化床燃烧

CLC Number:

X511

WANG Hui, DUAN Yufeng, LI Yaning, XUE Yuan, LIU Meng. Mercury emission and speciation distribution under oxy coal combustion in fluidized bed[J]. Chemical Industry and Engineering Progree, 2016, 35(10): 3362-3366.

王卉, 段钰锋, 李雅宁, 薛源, 刘猛. 煤在富氧流化床燃烧条件下汞的析出及形态分布[J]. 化工进展, 2016, 35(10): 3362-3366.

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