义马褐煤显微组分酸性含氧基团特征及其抑制甲烷吸附性

Acidic oxygen-containing groups and their inhibition methane adsorption of Yima lignite maceral components

为探索煤表面酸性含氧基团对低阶煤甲烷吸附行为的影响,采集义马褐煤样品经手选、破碎、研磨、筛分并重液分离富集不同显微组分,借助傅立叶变换红外光谱(FT-IR)测试,Boehm滴定等技术表征褐煤各显微组分富集物酸性含氧基团特征,依据煤化学统计结构解析法推算褐煤基本结构单元萘核,利用重量法等温吸附实验测定褐煤各显微组分富集物及不同酸性含氧基团特征结构化合物的甲烷吸附性.研究发现:义马褐煤酸性含氧基团总量与羧基、酚羟基、内酯基含量最高的显微组分依次为类脂组、腐殖组、惰质组;不同酸性含氧基团对褐煤萘核的抑制甲烷吸附性由大到小依次为羧基,酚羟基,内酯基.其中,羧基相对抑制甲烷吸附量约为内酯基与酚羟基的7倍和3.3倍;在忽略水分条件下考察褐煤显微组分富集物中不同酸性含氧基团对甲烷的吸附行为,结果显示羧基含量增高是造成各显微组分甲烷吸附量降低的主要因素.本研究表明,显微组分含量及煤表面性质是影响褐煤含气性的重要因素,惰质组的高羧酸含量抑制义马褐煤甲烷吸附性效果显著.

To explore effects of acidic oxygen-containing groups on adsorption behavior of lowrank-coal methane,on the basis of collecting and separating maceral components of Yima lignite,acidic oxygen-containing groups of lignite maceral components were characterized by means of FT-IR and Boehm titration.The basic structural unit nuclei was calculated via coal chemical statistical structure analysis,and methane adsorption of the maceral component enrichments and the model compounds with different acidic oxygen-containing groups were determined through weight method.The results show that：the highest total amount of acidic oxy-gen-containing groups and the highest content of carboxyl,phenolic hydroxyl and lactone in the maceral-component enrichments are liptinite,humic and interia.By different acidic oxygencontaining groups,apriority order for methane adsorption inhibition on lignite naphthalene is carboxyl,phenolic hydroxy,lactone;the relative adsorption inhibition of the carboxyl is about7 times and 3.3 times that of the lactone and the hydroxyl.Without considering the water condition,carboxyl content increasing is the main factor resulting in the amount decreasing of methane adsorption capacity of each maceral component.The study reveals that the surface property and content of maceral components are important factors affecting the gas content of lignite,and the higher content of carboxylic acid in Yima lignite inertial group is significant for methane adsorption inhibition.