摘要
在亚临界H_(2)O-CO体系中开展了褐煤改性增黏研究,利用气相色谱(GC)、傅立叶变换红外光谱(FTIR)、^(13)C核磁共振(^(13)C-NMR)、热重分析(TG)和电子自旋共振(ESR)等方法,探索了CO对煤黏结性、结构特征和自由基变迁规律的影响,进而认识了CO对煤改性增黏的作用机制。结果表明:在CO初压为4.5 MPa时对褐煤进行改性,褐煤的黏结指数(G RI)可由0显著提高至91.35。CO通过水煤气变换反应(WGSR)向体系提供活性氢(H·),提高CO初压促进了H·的生成,有利于H·向煤分子结构内部扩散实现加氢。同时,在CO初压为4.5 MPa时,褐煤中的亚甲基、氧桥键和甲基侧链等会发生断裂,并生成大量自由基,提高了芳香片层的活动性,以促进褐煤中较小的芳香层片重排形成中等分子多环芳烃自由基,这些自由基可被体系中活性氢H·稳定而生成前沥青烯等黏结性物质,从而提高了煤的黏结性。
The development of the caking characteristic for the lignite by using the hydro-modification was carried out in a subcritical H_(2)O-CO system.The effects of CO on the caking property,structural characterization and free radical evolution were investigated by using gas chromatography(GC),Fourier transform infrared spectroscopy(FTIR),^(13)C magnetic resonance imaging(13 C-NMR),thermogravimetry(TG)and electron spin resonance(ESR).The results show that the caking property of the lignite can be clearly developed and the caking index(G RI)of the modified coal increases from 0 to 91.35 when the initial pressure of CO is 4.5 MPa.CO provides active hydrogen(H·)to the reaction system through the water gas shift reaction(WGSR).The increase in the CO initial pressure promotes the formation of H·,which is conducive to the entrance of H·into the coal molecular structure to achieve the hydrogenation.Meanwhile,at the CO initial pressure of 4.5 MPa,the bridge-bonds of methylene and oxygen and the methyl side chains in the lignite can be broken,leading to the generation of a large number of free radicals.It improves the activity of the aromatic lamellar to rearrange and generate polyaromatic free radicals that can be stabilized by H·to form plastic species such as preasphaltene.To this end,the caking property of the lignite is improved.
作者
赵钰琼
何守琪
魏永永
王莉萍
安娜
张永发
ZHAO Yuqiong;HE Shouqi;WEI Yongyong;WANG Liping;AN Na;ZHANG Yongfa(Key Laboratory of Coal Science and Technology of Ministry of Education and Shanxi Province,Taiyuan University of Technology,Taiyuan 030024,China;Shanxi Guoxin Energy Corporation Limited,Taiyuan 030006,China;College of Chemistryl and Chemical Engineering,Taiyuan University of Technology,Taiyuan 030024,China)
出处
《煤炭转化》
CAS
CSCD
北大核心
2021年第5期1-9,共9页
Coal Conversion
基金
国家自然科学基金资助项目(21805203)
山西省研究生创新创业项目(2020SY540)
山西省高等学校大学生创新创业训练项目(2020100).
关键词
褐煤
加氢改性
黏结性
一氧化碳
亚临界水
lignite
hydro-modification
caking property
carbon monoxide
subcritical water
