煤显微组分热解过程中脂肪氢的演化特征及其动力学

摘要

The thermal evolution characteristics and kinetics of the aliphatic hydrogen in coal macerals were investigated by using heating stage and FTIR.The results showed that three stages were involved in the variation of the aliphatic hydrogen content:rapid decrease stage,slow decrease stage and changeless stage.With increasing temperature,the cracking of aliphatic carbochain,the cyclialkylation,the aromatization reaction, the hydrogenation of aromatic structure and the aromatic condensation reaction would take place in turn on coal macromolecule.The kinetic analysis illustrated that the removal of aliphatic hydrogen had low activation energy,which relating to lots of free radicals in the thermal reaction system.The relative removal rate of methyl and methylene group showed the shape of M with the increase of temperature.%采用热台与FTIR考察了平朔煤和神东煤显微组分热解过程中脂肪氢的演化特征.结果表明,随着热解温度的升高,脂肪氢经历了快速减少、缓慢减少和基本不变三个阶段,揭示出煤大分子体系依次发生了脂肪碳氢链的裂解、环烷化反应、芳构化反应、芳香结构氢化反应以及芳香缩合反应等;动力学分析表明,脂肪氢脱除反应的活化能较低,与反应体系中存在大量自由基有关;甲基与亚甲基的相对脱除速率随温度呈现M型关系.