不同变质程度煤燃烧反应性及FTIR分析其热解过程结构变化

利用TG/DTA 6300的热重分析仪对胜利褐煤(SL)、神华烟煤(SH)与塔旺陶勒盖无烟煤(TT)三种不同变质程度的原煤进行空气气氛下燃烧反应;通过FTIR(傅里叶变换红外光谱)分析了三种煤样及不同终温下固定床热解半焦的官能团组成;运用数学高斯函数对FTIR曲线重叠吸收峰进行分峰拟合，利用拟合峰面积计算FTIR的芳香度指数(R)、芳香结构稠合指数(D)及有机成熟度指数(C)结构参数。结果表明： SL，SH与TT煤着火温度分别为299.3，408.2及441.0℃;最大失重速率峰温度分别为348.6，480.5及507.0 ℃，即随煤样变质程度的不同，着火点和最大失重速率温度都不同程度提高。煤中官能团结构较复杂，不同变质程度的煤样的红外光谱曲线中均可以观察到羟基(—OH);脂肪烃(—CH₂，—CH₃);芳环(CC); 含氧官能团(CO， C—O)等主要官能团的振动吸收峰。随着热解炼焦温度的升高，三种煤样中脂肪烃类(—CH₂—，—CH₃)红外振动吸收峰均逐渐减小;炼焦后CO在1 700 cm-1伸缩振动峰在炼焦温度到达550 ℃时基本消失;SL原煤样在1 000～1 800 cm-1 含氧官能团吸收峰区域红外曲线更为复杂，随炼焦温度升高较之其他煤样变化最为显著;而SH及TT煤芳环CC吸收峰在温变过程中峰位及峰强度均无显著变化。通过R，D及C值随热解终温的变化曲线，三种变质程度煤在热解反应过程中主体官能团变化趋势存在差异。

Coal Combustion Reactivity of Different Metamorphic Degree and Structure Changes of FTIR Analysis in Pyrolysis Process

The combustion reaction of raw coals in the air was analyzed withThermal Gravimetric Analyzer 6300 and FTIR (Fourier Transform infrared spectroscopy).The raw coals came from three different sources which were SL lignite,SH bitumite and TT anthracite.The chars were prepared by fixed bed pyrolysis equipment in different reaction temperature.The overlapping peaks were fitted into some sub-peaks by Gaussian function.The aromatic index (R),aromatic structure fused index (D)and organic maturity index (C)were calculated through sub-peaks areas.It showed that three kinds of ignition temperature of SL, SH and TT were 299.3,408.2 and 441.0 ℃ respectively.The peak temperature of maximum weight loss rate were 348.6, 480.5 and 507.0 ℃ respectively.With the increase of coal rank,both ignition temperature and peak temperature of maximum weight loss rate increased in some degree.The result showed that coal structure was very complex.Vibration absorption peaks of hydroxyl (—OH ), aliphatic hydrocarbons (—CH2 ,—CH3 ), aromatic (C—C), oxygen-containing functional group (C—O, C—O)and other major functional groups could be observed in the infrared spectral curves of all samples.With the in-crease of pyrolysis temperature,infrared vibration absorption peaks of aliphatic hydrocarbons (—CH2—,—CH3 )were gradual-ly decreased.the stretching vibration peak of C—O which was at 1 700 cm-1 almost disappeared after coked at 550 ℃.SL samples’absorption peak area infrared curve of oxygen functional groups at 1 000~1 800 cm-1 was more complex.With the in-crease of coking temperature they changed more significantly compared with others.While peak position and peak intensity for aromatic C—C absorption peaks of SH and TT did not change apparently when temperature was changing.Variation trends of main functional groups among three ranks of coals were obviously different with changes of R,D and C values.