内在矿物质对煤粉燃烧过程影响的动力学研究  

Influence of Included Minerals Release on Dynamic Behavior of Pulverized Coal Combustion

作　　者：杜晓杰 李水清[1] 高琦[1] 姚强[1] Du Xiaojie,Li Shuiqing,Gao Qi,Yao Qiang(Key Laboratory for Thermal Science and Power Engineering of Ministry of Education,Department of Energy and Power Engineering,Tsinghua University,Beijing 100084,Chin)

机构地区：[1]清华大学能源与动力工程系热科学与动力工程教育部重点实验室,北京100084

出　　处：《燃烧科学与技术》2018年第3期270-274,共5页Journal of Combustion Science and Technology

基　　金：国家重点基础研究发展计划(973计划)资助项目(2013CB228501);国家科技支撑计划资助项目(2015BAA04B03)

摘　　要：本文采用数学建模方法研究煤粉内在矿物质析出对其燃烧的动力学影响.在MIT Graham研究工作的基础上,借鉴内在矿物质群平衡演化析出模型,建立包含表面矿物质结构演化的焦炭燃烧动力学模型.理论分析表明,在焦炭燃烧过程中,表面矿物质层内的气体传质过程会经历由分子扩散到努森扩散的转变.与已有的焦炭燃烧灰壳模型进行对比分析,结果表明,已有灰壳模型在焦炭燃烧初期较高地估计了表面矿物质对气体传质的抑制作用.当内在矿物含量低于10%(质量分数)时,焦炭燃烧全过程中内部矿物质对气体传质的抑制作用不明显.The influence of included minerals release on the coal combustion process is studied using mathematical modeling method.First,a reduced combustion model of char particles under conventional condition is established based on the research of Graham from MIT.Then,with a further introducion of the population-balance model,a dynamic coal combustion model with mineral evolutions on the char particle surface is built.Theoretical analysis shows that the gas transfer through surface minerals undergoes the conversion from molecular diffusion to Knudsen diffusion during pulverized coal combustion.Compared with the ash film model,results suggest that the existing ash film model overestimates the restraint of surface minerals on diffusion in the early stage of combustion.Furthermore,the restraint of minerals on diffusion during the whole combustion process is insignificant when the included minerals proportion is less than 10%.

关 键 词：内在矿物质 分子扩散 努森扩散 焦炭燃烧表面温度 

分 类 号：TK16[动力工程及工程热物理—热能工程]