准东煤在O_(2)/H_(2)O/CO_(2)气氛下脱挥发分过程焦炭结构演化特性研究  

Study on structure evolution characteristics of Zhundong coal char during devolatilization in O_(2)/H_(2)O/CO_(2) atmosphere

作　　者：刘晓倩 刘银河[1] 吕强[1] LIU Xiaoqian;LIU Yinhe;LYU Qiang(School of Energy and Power Engineering,Xi’an Jiaotong University,Xi’an 710049,China)

机构地区：[1]西安交通大学能源与动力工程学院,陕西西安710049

出　　处：《热力发电》2022年第1期139-149,共11页Thermal Power Generation

基　　金：国家自然科学基金项目(51576158)。

摘　　要：富氧燃烧技术不仅是先进的碳捕集技术,且可通过气化吸热反应降低燃烧温度减少碱金属的析出,缓解燃用准东煤产生的积灰结渣等问题,提高准东煤的利用率。但循环烟气代替空气助燃,氧化反应与气化反应相互作用,会影响煤焦反应活性。为保证在有限反应空间内煤焦的燃烧效率,研究煤焦结构演化规律,对合理组织炉内燃烧、改善煤焦燃烧过程至关重要。在固定床上制焦,采用拉曼和傅里叶红外光谱仪研究煤焦微晶结构和官能团的演化过程。结果表明:O_(2)或CO_(2)单独与煤焦反应时,易生成芳香类碳结构,而H_(2)O与煤反应过程中更易生成脂肪类氢结构;无论在何种气氛下反应,煤焦内部均经历大分子结构的分解、无定形碳结构的生成和逐步石墨化的过程,气氛的改变影响的是有机物分解析出的过程;O_(2)与CO_(2)同时存在时,气化剂体积分数增加先促进芳香结构的解体生成易反应的脂肪链结构;而O_(2)与H_(2)O同时存在时,O_(2)体积分数增加会加速芳香结构的生成,H_(2)O体积分数增加,则反应首先消耗脂肪链结构,然后促进芳香结构解体,生成脂肪链结构。Oxy-fuel combustion technology is not only an advanced carbon capture technology,but also can improve the Zhundong coal utilization rate by controlling combustion temperature through gasification reactions,which alleviates the problems of ash deposition and slagging caused by burning Zhundong coal.However,the circulating flue gas replaces air for combustion-supporting and the oxidation reaction and gasification reaction interacts with each other,which affects the reactivity of coal char.In order to ensure the combustion efficiency of coal in a limited reaction space,it is essential to study the evolution law of coal char structure for reasonably organizing combustion in the furnace and improving the combustion process of coal char.By preparing coal char in fixed bed,this paper used Raman and Fourier transform infrared spectroscopy to investigate the changes of microcrystalline structure and functional groups of the coal char.The results show that,aromatic carbon structure was easily formed when O_(2) or CO_(2) reacted with coal alone,while aliphatic hydrogen structure was more easily formed when H_(2)O reacted with coal.No matter what kind of atmosphere,the coal underwent the decomposition of macromolecular structure,the formation of amorphous carbon structure and the gradual graphitization process.The change of atmosphere affected the decomposition and precipitation of organic matters.When O_(2) and CO_(2) coexisted,the increasing gasifying agent concentrations promoted the decomposition of aromatic structures to generate reactive aliphatic chains.However,when O_(2) and H_(2)O coexisted,the O_(2) concentration increasing accelerated the formation of stable aromatic structure,but with the H_(2)O concentration increasing,the reaction first consumed the aliphatic chain structure and then promoted the decomposition of aromatic structure to generate the aliphatic chain structure.

关 键 词：准东煤 O_(2)/CO_(2)/H_(2)O/N_(2) 相互作用 微晶结构 官能团 焦炭 

分 类 号：TQ534[化学工程—煤化学工程]