摘要
在工业室式炼焦过程中,膨胀压力过高会造成焦炉炉墙损坏及推焦困难,膨胀压力过低会影响焦炭产品质量。现行焦化工艺通过调节入炉煤挥发分控制膨胀压力,缺乏对炼焦煤膨胀压力形成机制的本质认识,可能导致焦炉运行不稳定、焦炭质量波动大等问题。基于此,通过分析炼焦煤结构特性,从分子水平探究了膨胀压力的形成及演变,并揭示了炼焦煤膨胀性与焦炭质量的本质联系。利用核磁共振碳谱(^(13)C NMR)分析了五种不同煤阶的炼焦煤(Q1,JA1,F1,J1和S1)的化学结构。通过热重分析(TGA)、小型热解实验等方法以及基式流动度测定仪、奥亚膨胀仪、透气性在线检测装置及膨胀压力和膨胀位移检测装置等仪器探究了单种煤热解过程中煤基体分解行为、流动特性和膨胀特性的演化机制。结果表明:热解气体CO,CO_(2),CH4的释放和低透气性带的形成影响了膨胀压力的产生,适宜的膨胀压力可提高焦炭质量;300℃~450℃是煤产生膨胀压力的温区,与煤中f_(al)^(O1),f_(al)^(O2)和f_(al)^(1)~f_(al)^(5)结构的分解有关;膨胀压力过高(120 kPa~180 kPa)的煤,形成的焦炭孔隙多、真密度小,质量差;膨胀压力适中(90 kPa~120 kPa)的煤,形成的焦炭质量较好。
In the industrial chamber coking process,excessive swelling pressure can cause damage to the coke oven walls and difficulties in coke pushing,while too low swelling pressure affects the quality of coke products.The current coking process controls the swelling pressure by adjusting the volatile matter of the coal charged into the oven,but lacks a fundamental understanding of the mechanism behind the formation of swelling pressure in coking coal,resulting in possible unstable operation of coke oven and significant fluctuations in coke quality.Therefore,the structural characteristics of coking coal was analyzed and the formation and evolution of swelling pressure was explored from the molecular level,and the essential connection between the swelling characteristic of coking coal and coke quality was revealed.The chemical structures of five coking coals(Q1,JA1,F1,J1 and S1)with different coal ranks were analyzed using carbon-13 nuclear magnetic resonance spectrometry(^(13)C NMR).The evolution mechanism of the decomposition behavior,flowing characteristics,and swelling characteristics of the coal matrix during the pyrolysis process of a single coal was explored using thermogravimetric analysis(TGA),small-scale pyrolysis experiments,Gieseler fluidity,Audibert-Arnu dilatometer,permeability test device,and swelling pressure and swelling displacement detection devices.The results indicate that the release of pyrolysis gases such as CO,CO 2 and CH 4,as well as the formation of low-permeability zone,have an impact on the generation of swelling pressure,and an appropriate swelling pressure can improve the coke quality.The swelling pressure is found to be generated in coal in the temperature range of 300℃-450℃,which is related to the structural decomposition of f_(al)^(O1),f_(al)^(O2),and f_(al)^(1)-f_(al)^(5) in the coal.Coal with excessively high swelling pressure(130 kPa-180 kPa)forms coke with many pores and lower true density,resulting in inferior coke quality.While coal with moderate swelling pressure(90 kPa-110 kPa)produces better quality coke.
作者
王帅
周文艳
高亚芳
申岩峰
王美君
常丽萍
WANG Shuai;ZHOU Wenyan;GAO Yafang;SHEN Yanfeng;WANG Meijun;CHANG Liping(State Key Laboratory of Clean and Efficient Coal Utilization,Taiyuan University of Technology,030024 Taiyuan,China;Key Laboratory of Coal Science and Technology(Taiyuan University of Technology),Ministry of Education,030024 Taiyuan,China;Shanxi Coking Coal Group Company Limited,041606 Linfen,China)
出处
《煤炭转化》
CAS
CSCD
北大核心
2024年第2期30-43,共14页
Coal Conversion
基金
山西省重点研发计划项目(202102090301002)
山西焦化股份有限公司技术开发项目(GFPMJS(2022)004)。
关键词
煤化学结构
流动特性
膨胀特性
演化机制
焦炭质量
coal chemical structure
flowing characteristics
swelling characteristics
evolution mechanism
coke quality
