不同溶剂预处理煤在ScCO_(2)作用下的谱学差异及其机制  

Spectroscopic Differences in Different Solvent Pretreated Coals in the Presence of ScCO_(2)and Their Mechanisms

作　　者：张小东[1] 亢红东 李冰辉 张硕[1] 韩磊 ZHANG Xiao-dong;KANG Hong-dong;LI Bing-hui;ZHANG Shuo;HAN Lei(Department of New Energy and Science Engineering,School of Energy Science and Engineering,Henan Polytechnic University,Jiaozuo 454000,China;The First Institute of Resources and Environment Investigation of Henan Province,Zhengzhou 450000,China)

机构地区：[1]河南理工大学能源科学与工程学院新能源科学与工程系,河南焦作454000 [2]河南省资源环境调查一院,河南郑州450000

出　　处：《光谱学与光谱分析》2024年第9期2657-2666,共10页Spectroscopy and Spectral Analysis

基　　金：国家自然科学基金项目(42172198,42202210);河南省科技攻关计划项目(232102320336)资助。

摘　　要：为了探究溶剂预处理后超临界二氧化碳(ScCO_(2))对煤化学结构的影响,以长治霍尔辛赫贫煤为研究对象,分别用四氢呋喃(THF)、盐酸(HCI)和氢氟酸(HF)对煤样进行预处理,采用傅里叶红外光谱(FTIR)、固体核磁共振(^(13)C-NMR)和X射线衍射(XRD)测试,探讨了ScCO_(2)对预处理煤的化学组成和结构的影响机理。研究表明:①FITR分峰拟合谱图实验曲线基本一致,而各官能团吸收峰位置及峰强度仍出现一定的偏差,酸(HCI、HF)预处理后部分波段脂肪族峰位消失。两类酸预处理顺序不同,对煤中含氧官能团、脂肪结构及芳烃结构作用效果也不相同。HF-HCI处理后芳烃C=C结构和含氧官能团峰强度均增强,而HCI-HF处理后芳烃C=C结构强度减弱,含氧官能团结构峰强度变化不明显。THF预处理后煤样芳烃C=C结构峰强度增强,含氧官能团结构峰强度降低。总体芳烃C=C结构峰强度远大于脂肪族结构和含氧官能团结构的峰强度。②^(13)C-NMR谱中主要官能团谱峰的化学位移出现了一定程度的偏移,芳香碳f_(a)^(B)化学位移向增大的方向偏移。大分子结构参数中,芳香碳含量远大于脂肪碳含量,说明煤大分子结构中芳香碳占主要组成部分。③XRD谱中002峰与101峰衍射强度明显增大,芳香微晶层网面间距d_(002)呈现升高趋势,说明THF、酸(HF、HCI)处理和ScCO_(2)对煤大分子结构产生了一定程度的改造作用,使煤的大分子网络结构变得疏松,进而使微晶结构参数d_(002)整体增大。研究认为,溶剂作用后煤的谱学特征变化不仅与溶剂性质有关,还与无机酸处理顺序有关,由此使得官能团组成和大分子结构不同程度改变,进而影响ScCO_(2)对预处理煤的萃取效果。The purpose of this study is to study the effect of supercritical carbon dioxide(ScCO_(2))on the chemical structure of coal after solvent pretreatment.The lean coal samples collected from Changzhi Huoerxinhe were adopted.Coal samples were pretreated with tetrahydrofuran(THF),hydrochloric acid(HCI),and hydrofluoric acid(HF),respectively.The Fourier transform infrared spectroscopy(FTIR),solid-state nuclear magnetic resonance(^(13)C-NMR),and X-ray diffraction(XRD)were used to study the chemical composition and structure of coal samples.Results show that:①The FITR peak-fitting spectra were basically consistent with the experimental curves,but the positions and intensities of the absorption peaks of each functional group still showed some deviations,and the aliphatic peaks disappeared in part of.the bands after the pretreatment with acids(HCI and HF).The two types of acid pretreatment order are different,and the effect on the oxygenated functional group,fat structure,and aromatic structure of coal is not the same.The intensityofaromatic C=C structureandoxygenatedfunctional grouppeakswereenhancedafterHF-HCItreatment.Incontrast,the intensityof the aromatic C=C structure was weakened after HCI-HF treatment,and the intensity of the structure of the oxygenated functional group was insignificant.The intensity of the aromatic C=C structure of the coal samples was enhanced,and the intensityof the structure of the C=C oxygenated functional group was reduced after THF pretreatment.After THF pretreatment,the intensityof the aromatic C=C structure was enhanced,and the intensityof the C=C oxygenated functional group was reduced.Overall,the intensity of aromatic C=C structure is much larger than that of aliphatic structure and oxygenated functional group structure.②In the ^(13)C-NMR spectrum,the chemical shift of the main functional group peaks exhibits a certain degree of deviation.Aromatic carbon faB chemical shifts are overall shifted in the direction of increasing.The proportion of aromatic carbon is much greater than that

关 键 词：超临界二氧化碳(ScCO_(2)) 溶剂预处理 傅里叶变换红外光谱 固体核磁共振(^(13)C-NMR) 化学结构 

分 类 号：TQ531[化学工程—煤化学工程]