【摘要】：煤的自燃氧化是一個(gè)復(fù)雜的動(dòng)力學(xué)過(guò)程,深入分析與掌握煤氧化的動(dòng)力學(xué)規(guī)律,對(duì)研究煤自然著火有著非常重要的意義。以三種低階煤為研究對(duì)象,兩種高階煤為對(duì)比煤樣,選用Redfern-Coats積分方程對(duì)煤自燃最概然機(jī)理函數(shù)進(jìn)行推斷,得出了低階煤在失水脫附階段屬于一級(jí)化學(xué)反應(yīng),吸氧增重階段屬于三維擴(kuò)散機(jī)理函數(shù)。經(jīng)過(guò)計(jì)算發(fā)現(xiàn),低階煤的活化能低于高階煤種,而且隨著溫度的升高,反應(yīng)程度加深,活化能增大,指前因子也隨之增加。通過(guò)對(duì)煤樣的產(chǎn)熱速率進(jìn)行分析發(fā)現(xiàn),煤的低溫氧化都經(jīng)歷了吸熱然后再放熱的過(guò)程,產(chǎn)熱速率隨溫度的升高而增加,低階煤的初始放熱溫度較低,而總放熱量卻高于高階煤種。利用程序升溫氧化系統(tǒng)和傅里葉紅外光譜儀,通過(guò)對(duì)煤氧化過(guò)程中的氣體產(chǎn)物和官能團(tuán)的變化情況的分析發(fā)現(xiàn),在氧化過(guò)程中最先出現(xiàn)的是CO氣體,緩慢氧化階段CO氣體產(chǎn)量較少,曲線平緩。隨著溫度的升高氣體產(chǎn)量逐漸增加,烴類(lèi)氣體也逐漸產(chǎn)生。低階煤分子結(jié)構(gòu)中的脂肪烴和含氧官能團(tuán)含量明顯大于變質(zhì)程度高的煤,而且這兩種基團(tuán)活性較高,在氧化過(guò)程中變化明顯。經(jīng)研究推斷出CO直接來(lái)源于醛基,而烴類(lèi)氣體主要是由脂肪鏈的斷裂產(chǎn)生。低階煤結(jié)構(gòu)復(fù)雜,穩(wěn)定性差,在反應(yīng)過(guò)程中易于分解,生成大量氣體,自燃危險(xiǎn)性較大。煤的氧化是多步反應(yīng),不同步驟之間相互競(jìng)爭(zhēng)又相互聯(lián)系,反應(yīng)速率隨溫度升高逐漸加快,參與反應(yīng)的分子數(shù)量也隨之增加。
[Abstract]:The spontaneous combustion oxidation of coal is a complicated dynamic process. It is very important to analyze and master the kinetic law of coal oxidation. Taking three kinds of low-rank coal as the research object and two kinds of high-order coal as contrast coal samples, the Redfern-Coats integral equation is used to infer the most probable mechanism function of coal spontaneous combustion, and it is concluded that the low-rank coal is a first-order chemical reaction in the desorption stage of water loss. The phase of oxygen absorption and weight gain belongs to three dimensional diffusion mechanism function. The results show that the activation energy of low-rank coal is lower than that of high-order coal, and with the increase of temperature, the degree of reaction deepens, the activation energy increases and the pre-exponential factor increases. Through the analysis of the heat production rate of coal samples, it is found that the low temperature oxidation of coal goes through the process of endothermic and then exothermic, the heat production rate increases with the increase of temperature, and the initial exothermic temperature of low rank coal is lower. However, the total heat release is higher than that of high-order coal. By using the temperature programmed oxidation system and Fourier transform infrared spectrometer, it is found that CO gas is the first one to appear in the oxidation process by analyzing the changes of gas products and functional groups in the process of coal oxidation. At the stage of slow oxidation, CO gas production is less and the curve is smooth. With the increase of temperature, the production of hydrocarbon gas increases gradually. The content of aliphatic hydrocarbons and oxygen-containing functional groups in the molecular structure of low-rank coal is obviously higher than that in high-grade metamorphic coal, and the activity of these two groups is higher, and the changes are obvious during the oxidation process. It is inferred that CO is directly derived from aldehyde group, while hydrocarbon gas is mainly produced by the breakage of fatty chain. The structure of low rank coal is complex, the stability is poor, it is easy to decompose in the reaction process, produce a large amount of gas, and the danger of spontaneous combustion is great. The oxidation of coal is a multi-step reaction. The reaction rate increases with the increase of temperature and the number of molecules participating in the reaction increases.
【學(xué)位授予單位】：華北理工大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類(lèi)號(hào)】：TD752.2

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相關(guān)期刊論文 前10條

1 魏琰榮;肖翠微;王乃繼;王永英;;補(bǔ)連塔煤低溫氧化特性的熱重研究[J];潔凈煤技術(shù);2016年01期

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本文編號(hào)：2149549