基于量子化学计算的煤低温氧化放热强度  

Exothermicity of coal during low temperature oxidation process based on quantum chemical calculation

作　　者：高飞[1,2] 白企慧 贾喆 滕弋非 李应迪 GAO Fei;BAI Qihui;JIA Zhe;TENG Yifei;LI Yingdi(School of Safety Science and Engineering,Liaoning Technical University,Huludao125100,China;Key Laboratory of Mine Thermodynamic Disasters and Control of Ministry of Education,Liaoning Technical University,Huludao 125100,China)

机构地区：[1]辽宁工程技术大学安全科学与工程学院,辽宁葫芦岛125100 [2]辽宁工程技术大学矿山热动力灾害与防治教育部重点实验室,辽宁葫芦岛125100

出　　处：《煤炭学报》2023年第9期3428-3440,共13页Journal of China Coal Society

基　　金：国家自然科学基金面上资助项目(51874161)。

摘　　要：煤分子结构是影响煤氧化放热特性的根本原因。以水峪(SY)烟煤为研究对象,采用量子化学计算与工业和元素分析、傅里叶变换红外光谱(FT-IR)、X射线光电子能谱(XPS)、程序升温、差示扫描量热等相结合的方法,构建并优化SY煤的三维分子模型,并对煤的低温氧化放热强度进行研究。研究成果如下:SY煤的变质程度较高,其中碳元素主要以四取代的芳香烃和环烷烃形式存在,氮和硫元素主要以具有芳香性的吡咯和噻吩形式存在;碳氧官能团中醚氧键(C—O)、羰基(C=O)和羧基(COO—)的比例约为1.5∶1∶1.5,煤中氢键主要以羟基自缔合氢键为主。构建SY煤三维层状结构模型的分子式为C_(203)H_(140)O_(18)N_(2),分子量为2 893.01,确定煤低温氧化过程中的6种活性基团分别为:■;在煤的低温氧化阶段,前3种活性基团未发生开环反应,主要生成环己酮和H_(2)O,后3种活性基团可发生多步反应至最终产物为CO和CO_(2)。基团发生彻底氧化反应生成CO和CO_(2)的反应热分别为ΔH_(2)=-591.88 kJ/mol、ΔH_(3)=-7_(18).10 kJ/mol,未发生彻底氧化反应的最小反应热为ΔH_(min)=-366.99 kJ/mol,最大反应热为ΔH_(max)=-535.07 kJ/mol;结合耗氧速率、CO产生速率和CO_(2)产生速率,可计算得到SY煤在不同低温氧化阶段的放热强度,与差示扫描量热实验所得放热强度相比,计算值和实验值基本一致,说明采用量子化学方法计算煤放热强度的可行性。The molecular structure is the fundamental factor affecting the oxidation exothermic properties of coal.Shuiyu(SY)bituminous coal was characterized by the combination of quantum chemical calculation,proximate and ultimate analysis,fourier transform infrared spectroscopy(FT-IR),X-ray photoelectron spectroscopy(XPS),and temperature programmed and differential scanning calorimetry experiment.The three-dimensional molecular model of SY coal was constructed and optimized,and the low-temperature oxidation exothermicity of coal was studied.The results were as follows:the metamorphism degree of SY coal was high,in which the carbon elements mainly existed in the form of tetra-substituted aromatics and cycloparaffin,and the nitrogen and sulfur elements mainly existed in the form of aromatic pyrrole and thiophene.The ratios of ether-oxygen bond(C-O),carbonyl group(C=O)and carboxyl group(COO-)in the carbon-oxygen functional groups were about 1.5∶1∶1.5,and the hydrogen bonds in coal were mainly self-associated by hy-droxyl.The molecular formula of SY coal three-dimensional layered structure model was defined as C_(203)H_(140)O_(18)N_(2)(mo-lecular weight is 2893.01),during the low-temperature oxidation process,the six active groups in coal were determined as:■,respectively.In the low-temperature oxidation stage of coal,the first three active groups did not occur ring-opening reaction,and mainly generated cyclohexanone and H_(2)O,while the last three active groups underwent multi-step reactions and the final products were CO and CO_(2).During the above oxidation reaction,the reaction heats of the complete oxidation reaction to generate CO and CO_(2) were ΔH_(2)=−591.88 kJ/mol and ΔH_(3)=−7_(18).10 kJ/mol,while the minimum reaction heat of the incomplete oxidation reaction was ΔH_(max)=−366.99 kJ/mol,and the maximum reaction heat was ΔH_(max)=−535.07 kJ/mol.Combined with the O_(2) con-sumption rate,CO generation rate and CO_(2) generation rate,the exothermicity of SY coal in different low-temperature ox-idatio

关 键 词：放热强度 低温氧化 煤结构 量子化学计算 活性基团 

分 类 号：TD75[矿业工程—矿井通风与安全]