半焦-烟煤混燃特性及动力学分析

Co-combustion characteristics and kinetic analysis of semi-coke and bituminous coal

掺烧烟煤是解决低挥发分热解半焦着火难、燃尽差的一种有效方法。采用热重实验研究了半焦、无烟煤与烟煤混燃特性的差别,分析了混燃过程中的交互作用和反应动力学。结果表明:陕煤半焦的燃烧过程分为可燃质的燃烧和CaCO_3的分解两个阶段。半焦-烟煤混烧的主失重峰靠近燃料比接近的单燃料的DTG峰。半焦-烟煤混合燃料较无烟煤-烟煤混合燃料的综合燃烧特性更优。掺混烟煤比例越高,混燃的表观活化能越低,可燃性和综合燃烧特性越好。烟煤与半焦或无烟煤混燃过程中存在一定的交互作用,且无烟煤-烟煤的交互作用较半焦-烟煤更显著。可燃性指数和综合燃烧指数与燃料比呈负线性相关性,表观活化能E与燃料比呈正线性相关性。

Co-combustion of bituminous coal with low volatile semi-coke is an effective method,which can improve the ignition and burnout performance of semi-coke.This paper describes the combustion characteristics differences,interaction effect,kinetic analysis of semi-coke and anthracite blended with bituminous coal by applying thermogravimetric analyzer.The results indicate that the combustion process of semi-coke is divided into two stages:combustion of combustible materials,and decomposition of calcium carbonate in the semi-coke.The main mass loss peak of the blend fuels close to DTG peak of the single fuel,which has an approximate fuel ratio with the blend.The blend of semi-coke with bituminous coal has better ignition and comprehensive combustion characteristics than blend of anthracite with bituminous coal.Addition of bituminous coal can lower the apparent activation energy,and improve the ignition and burnout performance of semi-coke or anthracite.Moreover,the apparent activation energy decreased,while the ignition and comprehensive combustion characteristics index increased with the blend ratio of bituminous coal.There exist more significant synergetic effects between bituminous coal and semi-coke than between bituminous coal and anthracite.In addition,the ignition index and comprehensive combustion index reveals negative correlation with fuel ratio,while the apparent activation energy shows positive correlation with fuel ratio.