微波辅助铁催化华夏煤热解及煤焦结构演变特性  

Characteristics of microwave-assisted Fe-catalyzed pyrolysis of Huaxia coal and char structure evolution

作　　者：脱凯用 刘淑琴[1] 王莉萍 陈钢 马伟平 牛茂斐 刘欢 郭巍 TUO Kaiyong;LIU Shuqin;WANG Liping;CHEN Gang;MA Weiping;NIU Maofei;LIU Huan;GUO Wei(School of Chemical and Environmental Engineering,China University of Mining and Technology-Beijing,Beijing 100083,China;Shanxi High Carbon Energy Low Carbon Utilization Research and Design Institute Co.,Ltd.,Taiyuan 030006,China)

机构地区：[1]中国矿业大学(北京)化学与环境工程学院,北京100083 [2]山西高碳能源低碳化利用研究设计院有限公司,山西太原030006

出　　处：《煤炭学报》2021年第S02期1030-1041,共12页Journal of China Coal Society

基　　金：北京能源与材料领域应用技术协同创新资助项目(Z201100004520012);国家自然科学基金资助项目(51476185);中国矿业大学(北京)越崎杰出学者资助项目(2020JCB02)

摘　　要：微波热处理技术以其独特的快速均匀、选择性加热方式为基于热解转化的煤炭清洁高效利用提供了新途径。为研究微波辅助兼具催化活性和介电响应的Fe基催化剂对低阶煤热解升温和热失重特性、气体析出规律以及煤焦介电性能和碳微晶结构演变行为的影响,在微波管式热解炉上对华夏低阶煤进行了不同辐射时间下的Fe催化热解实验。借助矢量网络分析仪,N_(2)-吸附,FTIR,XRD,Raman和同步热分析仪等表征了煤焦物化性质。结果表明:引入Fe催化剂能够充分强化热解挥发分在5~15 min内的深度释放使得煤样呈现出更为明显的热失重。微波优先被Fe催化剂损耗可有效促进活性位点的生成,进而高效诱发了煤大分子官能团热裂解反应的发生,连续辐射5 min即可明显促进H_(2)和CO的快速生成,最终使得合成气产量由煤单独热解的198 mL/g显著提高至370 mL/g。煤微波辅助热解过程中Fe催化剂的引入有效抑制了煤焦芳香碳层的横向内部生长和纵向堆垛,进而显著提升了碳微晶不规整度以及丰富了碳骨架中的缺陷结构,有助于大幅提升煤焦气化反应速率使其气化反应指数增加4~5倍。Fe催化作用下挥发分的快速释放以及金属氧化物的生成充分强化了煤焦以热能形式耗散微波能的能力,进而使其介电损耗因子ε″_(r)在辐射10~20 min内呈现出大幅增加的突变。此外,微波辅助活性组分Fe能够侵蚀煤基质表面发挥造孔和扩孔作用,从而有利于煤焦高比表面积的形成以及发达孔隙结构的构筑。Microwave-thermal treatment offers a novel approach for the clean and high-efficient utilization of coal resources based on pyrolysis conversion due to its unique merits of quick and even heat transfer and optional heat transfer.This study investigated the effect of the Fe-based catalyst with both catalytic activity and dielectric response on the temperature-rising and thermal weight loss characteristics of coal samples,release law of gas components,dielectric properties and the evolution behavior of carbon microcrystalline structure of coal chars.Microwave-assisted Fe-catalyzed pyrolysis of Huaxia low-rank coal was carried out in a microwave tube furnace under different radiation time.Physicochemical properties of coal chars were characterized by vector network analyzer,N_(2)-adsorption,FT-IR,XRD,Raman and synchronous thermal analyzer.Results manifested that the introduction of the Fe catalyst could effectively enhance the deep release of pyrolysis volatiles within 5-15 minutes,resulting in the coal samples exhibiting a conspicuous thermal weight loss peak.Microwave interacted preferentially with the Fe catalyst could generate a large number of active sites,which efficiently induces the occurrence of thermal cracking reactions of coal macromolecular chains and functional groups.Microwave-assisted Fe is conducive to the rapid generation of H_(2)and CO within 5 minutes of continuous radiation,leading to the syngas yield is considerably improved from 198 mL/g of pure coal sample to 370 mL/g of coal sample load with the Fe catalyst.Furthermore,the appearance of Fe effectively inhibits the planar extension and longitudinal stacking of aromatic carbon layer of coal chars,which can significantly augment the irregularity of carbon crystallites and enrich the defect structure in the carbon skeleton,resulting in the gasification reaction index of coal chars increasing by 4-5 times through sufficiently enhanced gasification reaction rate.The rapid release of volatiles under the catalytic action of Fe and the generation of

关 键 词：微波热解 Fe催化剂 低阶煤 煤焦结构 介电性质 

分 类 号：TQ530.2[化学工程—煤化学工程]