摘要
为了揭示内蒙古褐煤(X-L和B-L)在热解过程中的破碎/粉化特性,提出了描述颗粒破碎/粉化的表征指标,利用实验室固定床和流化床试验装置研究不同热解条件对颗粒破碎/粉化的影响。结果表明,单独热力加载方式下的粒度变化率和粉化率分别为6.83%和2.95%,单独机械力加载方式下的粒度变化率和粉化率分别为2.72%和1.54%,单独热力加载方式下的粒度变化率和粉化率均高于单独机械力加载方式;单独热力加载方式下颗粒的总孔体积为原煤总孔体积的4.34倍,大孔和介孔的容积均大幅扩充,验证了半焦孔隙结构和粒度分布的改变主要与热力加载有关,机械力加载只会造成颗粒表面的破碎;在热力和机械力耦合加载作用下粒度变化率为9.76%,粉化率为5.09%,均高于单独热力或机械力加载方式;煤中挥发分越高,热解焦油产率越高时,颗粒粉化率越大;建立了煤热解破碎前后平均粒径关联的函数模型,与试验值对比相对误差较小(B-L对应相对误差≤3%,X-L对应相对误差≤10%),能够预测褐煤在热解过程中的破碎/粉化程度。
In order to reveal the fragmentation/pulverization characteristics of Inner Mongolia lignite(X-L and B-L)during pyrolysis,the characterization index of particle fragmentation/pulverization was proposed.The effects of different pyrolysis conditions on particle fragmentation/pulverization were investigated by using laboratory fixed bed and fluidized bed experimental device.The results show that the particle size change rate and pulverization rate are 6.83%and 2.95%respectively under the separate thermal loading mode,and 2.72%and 1.54%respectively under separate mechanical force loading mode.Therefore,the particle size change rate and pulverization rate under the separate thermal loading method are higher than those under the separate mechanical force loading method.The total pore volume of the particles under the single thermal loading method is 4.34 times of that of raw coal,and the volumes of macropores and mesopores are greatly expanded,which verifies that the change of pore structure and particle size distribution of char is mainly related to the thermal force loading,while the mechanical force loading will only cause the particle surface to be broken.The particle size change rate is 9.76%and the pulverization rate is 5.09%under the coupled loading of thermal and mechanical forces,which are higher than those under the loading mode of thermal or mechanical forces alone.The higher the content of volatile matter in coal is,the higher the yield of pyrolysis tar is,the higher the particle pulverization rate is.A function model of average particle size correlation before and after coal pyrolysis and fragmentation is established.The relative error between the model and the experimental value is small(The relative error corresponding to B-L≤3%,the relative error corresponding to X-L≤10%),which can predict the fragmentation/pulverization degree of lignite in the pyrolysis process.
作者
周琦
ZHOU Qi(Coal Chemistry Branch,China Coal Research Institute,Beijing 100013,China;State Key Laboratory of Coal Mining and Clean Utilization,Beijing 100013,China;National Energy Technology&Equipment Laboratory of Coal Utilization and Emission Control,Beijing 100013,China)
出处
《洁净煤技术》
CAS
北大核心
2021年第3期166-173,共8页
Clean Coal Technology
基金
国家重点研发计划资助项目(2018YFB0605004)。
关键词
褐煤
热解
破碎/粉化
热力
机械力
粉化率
lignite
pyrolysis
fragmentation/pulverization
thermal force
mechanical force
pulverization rate
