Calcium transformation during Zhundong coal combustion process

doi:10.11949/j.issn.0438-1157.20170350

Abstract

Abstract:

Sequential extraction was employed to determine the modes of occurrence of calcium in Zhundong coal.The samples from Zhundong coals before and after extraction were ashed in a high temperature atmosphere furnace.The calcium content of the coal and ash samples and the calcium-contained minerals in the samples were determined using an inductively coupled plasma atomic emission spectroscopy and X-ray diffraction analysis.The results indicated that the calcium contained in Zhundong coal was in the forms of water-soluble,ammonium acetate-soluble,hydrochloric acid-soluble and insoluble species,and the main calcium modes were the ammonium acetate-soluble and hydrochloric acid-soluble species,while the proportions of the water-soluble and insoluble-calcium were low.During the combustion process,the chemical reactions among the calcium-containing minerals,the silicon-containing minerals and aluminum-containing minerals in Zhundong coal occurred to form fukalite,mayenite,kilchoanite and rankinite.The base/acid ratio decreased and the ash melting temperature increased after water extraction.The hydrochloric acid-soluble calcium species reacted with the silicon-containing and aluminum-containing minerals,leading to form mayenite,kilchoanite and rankinite.The insoluble-calcium species existed in the form of margarite was stable in the coal during combustion process.

Key words: reaction, coal combustion, calcium, transformation

摘要：

采用3种萃取液（水、醋酸铵和盐酸）对准东煤进行逐级萃取实验，使用高温气氛炉对准东原煤及萃取后的煤样进行燃烧实验，使用电感耦合等离子体原子发射光谱仪和X射线衍射物相分析仪对萃取前后的固体煤样及燃烧后煤灰样品分别进行Ca元素分析和矿物检测。研究结果表明，准东煤中的钙元素主要以醋酸铵溶钙和盐酸溶钙形式存在。在燃烧过程中，准东煤中含钙矿物质与含硅、含铝矿物质反应生成硅钙石、斜硅钙石与钙铝石等；其中经水萃取后碱酸比减小，灰熔融温度升高，盐酸溶钙与含硅、含铝矿物质反应生成硅钙石、硅铝石等，不溶钙主要以稳定的硅铝酸盐形式存在。

关键词: 反应, 煤燃烧, 钙, 转化规律

CLC Number:

TK16

HUANG Xiaohe, ZHANG Shouyu, YANG Jingning, JIANG Fenghao, WU Shunyan, MU Chen, LÜ Junfu. Calcium transformation during Zhundong coal combustion process[J]. CIESC Journal, 2017, 68(10): 3906-3911.

黄小河, 张守玉, 杨靖宁, 江锋浩, 吴顺延, 慕晨, 吕俊复. 准东煤高温燃烧过程中含钙矿物质的转化规律[J]. 化工学报, 2017, 68(10): 3906-3911.

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