Morphology Structure Evolution and Combustion Reactivity of Bituminous Char at Around Ash Melting Temperature

ZHANG Yandi, YANG Huan, WANG Bo, H.M. Shahzaib KHAN, DUAN Xiaoli, LIU Yinhe

热科学学报 ›› 2022, Vol. 31 ›› Issue (6) : 2189-2202.

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热科学学报 ›› 2022, Vol. 31 ›› Issue (6) : 2189-2202. DOI: 10.1007/s11630-022-1686-6  CSTR: 32141.14.JTS-022-1686-6
燃烧和反应

Morphology Structure Evolution and Combustion Reactivity of Bituminous Char at Around Ash Melting Temperature

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Morphology Structure Evolution and Combustion Reactivity of Bituminous Char at Around Ash Melting Temperature

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摘要

在液态排渣炉中,煤焦颗粒被液态渣层捕获前后经历了一系列复杂的结构演变,演化结果对碳转化率具有重要影响。演化结构受到温度波动的影响较大,尤其是在灰熔融温度区间(900-1300℃)内。本文采用固定床研究了灰熔融温度区间内的烟煤焦炭的结构演变规律,并测量了不同温度下煤焦形态、比表面积和矿物成分。实验结果表明,随着温度升高,煤焦表面渗出的灰渣的数量和颗粒尺寸明显增加。气化产生的灰渣比表面积略大于燃烧产生的灰渣比表面积。热解过程中,焦炭中的氯化物残留量降为1%,同时在整个灰熔融温度区间内,Fe、K、Mg和Na的含量明显下降。演化过程中碳与矿物发生反应使得褐硫钙石的衍射强度增加,石英的衍射强度急剧下降。随着热解温度的升高,煤焦的点火温度和燃尽温度升高,燃烧稳定性降低。

Abstract

In slag tapping furnaces, char particles undergo a series of complex structural evolution before and after being captured by the liquid slag layer. The evolution results affect the carbon conversion rate and are affected by temperature fluctuations, especially in the ash melting temperature zone. Experimental study on structure evolution of bituminous char prepared at around ash melting temperature was carried out on a fixed bed. The morphology, specific surface area and mineral chemical composition were measured at different temperatures. Experimental results show that the number density and the size of ash droplets exuded on the char surface increased significantly with the increasing temperature. The ash specific surface area from gasification was slightly greater than that from combustion. The residual content of chloride in the char become 1% and the contents of Fe, K, Mg and Na decrease significantly during the pyrolysis process across the ash melting temperature zone. The diffraction intensity of oldhamite increase which indicates the reaction of carbon substrate with minerals during the evolution; the diffraction intensity of quartz dramatically decreases for the reason of anorthite generation. The ignition and burnout temperatures of char were found to increase and the combustion stability decreased with the increasing pyrolysis temperature.

关键词

coal char / structure evolution / carbothermal reaction / combustion

Key words

coal char / structure evolution / carbothermal reaction / combustion

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导出引用
ZHANG Yandi , YANG Huan , WANG Bo , H.M. Shahzaib KHAN , DUAN Xiaoli , LIU Yinhe. Morphology Structure Evolution and Combustion Reactivity of Bituminous Char at Around Ash Melting Temperature[J]. 热科学学报, 2022, 31(6): 2189-2202 https://doi.org/10.1007/s11630-022-1686-6
ZHANG Yandi , YANG Huan , WANG Bo , H.M. Shahzaib KHAN , DUAN Xiaoli , LIU Yinhe. Morphology Structure Evolution and Combustion Reactivity of Bituminous Char at Around Ash Melting Temperature[J]. Journal of Thermal Science, 2022, 31(6): 2189-2202 https://doi.org/10.1007/s11630-022-1686-6

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基金

The financial support from the Natural Science Fund of China (51576158) is gratefully acknowledged. We also thank the support of the Instrument Analysis Center of Xi’an Jiaotong University.

版权

Science Press, Institute of Engineering Thermophysics, CAS and Springer-Verlag GmbH Germany, part of Springer Nature 2022
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