本文選題：活性官能團(tuán) + 動力學(xué)特征�。� 參考：《西安科技大學(xué)》2017年博士論文

【摘要】：研究煤氧化過程的微觀機(jī)理是控制和預(yù)防煤自然發(fā)火的重要方法。本文通過理論分析、實(shí)驗(yàn)研究和統(tǒng)計計算三種手段相結(jié)合的方法,對淮南礦區(qū)6個煤礦的典型煤樣在氧化自燃過程的微觀特征和宏觀特性,以及兩者之間的關(guān)聯(lián)性進(jìn)行了詳細(xì)的分析,研究了在高溫氧化過程中,煤分子中官能團(tuán)變化規(guī)律及氧化氣體產(chǎn)物的動力學(xué)特性,為淮南煤自燃災(zāi)害的早期預(yù)測預(yù)報提供了指導(dǎo),并對在自燃過程中采取科學(xué)的防治措施提供了重要的理論依據(jù)。采用元素分析、工業(yè)分析、比表面積及孔徑分布分析、導(dǎo)熱特性、XRD微晶結(jié)構(gòu)參數(shù)分析、紅外光譜分析等測試技術(shù),分析了淮南煤的物理化學(xué)結(jié)構(gòu)特性,掌握了煤樣的煤質(zhì)組成以及內(nèi)部結(jié)構(gòu)特征。結(jié)果表明淮南煤質(zhì)的特點(diǎn)為低灰分、較高揮發(fā)分;比表面積較小,孔徑以中孔為主,常溫狀態(tài)下較難發(fā)生氧化;煤樣的熱擴(kuò)散系數(shù)隨著溫度的升高不斷減小,比熱容和導(dǎo)熱系數(shù)隨著溫度的升高不斷增大;微晶結(jié)構(gòu)中芳香環(huán)縮合程度中等,層片結(jié)構(gòu)較為有序,煤中主要含有高嶺石、地開石、方解石、石英和菱鐵礦等礦物成分;煤樣表面分子結(jié)構(gòu)中官能團(tuán)種類相似但數(shù)量不同,均能檢測到羥基、脂肪烴、芳香烴、含氧官能團(tuán)。通過原位漫反射傅里葉紅外光譜分析了煤氧化過程中微觀結(jié)構(gòu)特征及其變化規(guī)律,對四類官能團(tuán)中的21種基團(tuán)隨溫度變化的特性進(jìn)行分析發(fā)現(xiàn),羥基在升溫反應(yīng)過程中不斷減少,脂肪烴先增大后減小,芳香烴中Ar-CH基團(tuán)比較穩(wěn)定,呈現(xiàn)先增大后減小的現(xiàn)象,而C=C基團(tuán)一直緩慢減少,含氧官能團(tuán)在燃點(diǎn)溫度之前不斷增大,直至燃點(diǎn)溫度之后含量才有所減少。通過西安科技大學(xué)自主研發(fā)的高溫程序升溫實(shí)驗(yàn)系統(tǒng),測試了在升溫至500℃過程中的淮南煤氧化釋放的氣體產(chǎn)物變化規(guī)律,并根據(jù)指標(biāo)氣體增長率分析法測算出五個特征溫度點(diǎn),將整個氧化升溫過程分為四個階段,分別是臨界溫度階段、干裂-活性-增速溫度階段、增速-燃點(diǎn)溫度階段和燃燒階段。實(shí)驗(yàn)證明,在臨界溫度階段,CO和CO2氣體緩慢增長,超過該溫度階段直至增速-燃點(diǎn)溫度階段,碳氧類氣體含量迅速增長,燃燒溫度階段氣體濃度有所下降,繼而由于穩(wěn)定官能團(tuán)的斷裂,繼續(xù)上漲。CH4、C2H6和C2H4氣體在干裂-活性-增速溫度階段之前均增長緩慢,之后才開始急劇增長,到燃燒溫度階段達(dá)到峰值。利用高溫程序升溫實(shí)驗(yàn)數(shù)據(jù),采用兩種不同的動力學(xué)方法,對四個不同階段的動力學(xué)特性進(jìn)行計算研究,反應(yīng)所需活化能隨溫度階段的遞進(jìn)先降低后增大,燃燒階段所需活化能大于增速-燃點(diǎn)溫度階段。此外,通過差示掃描法對氧化過程中的放熱性進(jìn)行了計算。通過分析微觀特性與宏觀表征,選取灰色關(guān)聯(lián)性分析中的相對關(guān)聯(lián)度分析,對淮南煤氧化升溫的四個溫度階段中氧化釋放的氣體和放熱量與14種不同活性基團(tuán)之間的關(guān)聯(lián)度大小進(jìn)行統(tǒng)計分析,推斷出影響各個階段氣體和熱量釋放的主要官能團(tuán),分析發(fā)現(xiàn),前三階段中,羰基是影響宏觀氣體釋放和熱量產(chǎn)生的主要官能團(tuán),脂肪烴和芳環(huán)結(jié)構(gòu)是燃燒階段中產(chǎn)生氣體和熱量的主要官能團(tuán),且C=C結(jié)構(gòu)在燃燒階段才開始大量參與反應(yīng),釋放氣體產(chǎn)物。
[Abstract]:The microscopic mechanism of coal oxidation process is an important method to control and prevent coal spontaneous combustion. Through theoretical analysis, experimental research and statistical calculation, the micro and macro characteristics of the typical coal samples in the 6 coal mines in Huainan mining area and the correlation between them are carried out in this paper. The three methods are combined with the method of theoretical analysis, experimental research and statistical calculation. In the process of high temperature oxidation, the change law of the official energy group and the kinetic characteristics of the oxidation gas product are studied in the process of high temperature oxidation. It provides guidance for the early prediction and prediction of the Huainan coal spontaneous combustion disaster, and provides the important theoretical basis for the scientific prevention and control measures in the process of spontaneous combustion. Analysis of surface area and pore size distribution, thermal conductivity, XRD microcrystalline structure parameter analysis, infrared spectrum analysis and other testing techniques, analyzed the physical and chemical structure characteristics of Huainan coal, mastered the coal composition and internal structure characteristics of coal samples. The results show that the characteristics of coal quality in Huainan are low ash, high volatile, smaller specific surface area, and pore size. The thermal diffusion coefficient of coal samples decreases with the increase of temperature, and the ratio of heat capacity and thermal conductivity increases with the increase of temperature. The condensation degree of aromatic rings in the microcrystalline structure is moderate and the structure of the layer is more orderly. The main coal in the coal is kaolinite, calcite, calcite, quartz and rhombus. Minerals such as mineral components; the surface molecular structure of coal samples is similar but the number is different, all can detect hydroxyl, fatty hydrocarbon, aromatic hydrocarbon, oxygen containing functional group. Through in situ diffuse reflectance Fourier transform infrared spectroscopy, the microstructure characteristics and change rules of coal oxidation process are analyzed, and 21 groups in the four category functional groups vary with temperature. The analysis of the characteristics shows that the hydroxyl group decreases continuously during the heating reaction process, and the fatty hydrocarbons increase first and then decrease. The Ar-CH group in aromatic hydrocarbons is more stable, showing the phenomenon of first increasing and then decreasing, while the C=C group has been slowly decreasing, and the oxygen containing functional groups continuously increase before the ignition temperature, and the content decreases after the ignition temperature. After the high temperature programmed temperature experiment system developed by Xi'an University of Science And Technology, the change law of gas products released from Huainan coal oxidation in the process of heating up to 500 C was tested, and five characteristic temperature points were calculated according to the index gas growth rate analysis method. The whole oxidation heating process was divided into four stages, which were the critical temperature stage, respectively. It is proved that at the critical temperature stage, CO and CO2 gas increase slowly at the critical temperature stage, and the content of carbon and oxygen gas increases rapidly at the stage of the temperature and the temperature stage, and the gas concentration in the combustion temperature stage decreases, and then the stable functional group breaks down. Crack, continue to rise.CH4, C2H6 and C2H4 gas increase slowly before the dry cracking activity growth temperature stage, and then begin to increase rapidly and reach the peak in the combustion temperature stage. By using the high temperature temperature programmed experimental data, two different kinetic methods are used to calculate and study the dynamic characteristics of the four different stages. The activation energy is first reduced and then increased with the progressive of the temperature stage. The activation energy needed in the combustion stage is greater than that of the ignition point temperature. In addition, the heat release of the oxidation process is calculated by differential scanning. The relative degree analysis in the grey correlation analysis is selected by analyzing the microscopic and macroscopic characterization, and the coal oxygen in Huainan is selected. The correlation degree between the oxidizing gas and the release of heat and the 14 different active groups in the four temperature stages is statistically analyzed, and the main functional groups that affect the release of gas and heat at various stages are deduced. The analysis shows that the carbonyl groups are the main functional groups that affect the release of macro gases and the production of heat in the first three stages. The fatty hydrocarbon and aromatic ring structure are the main functional groups that produce gas and heat during the combustion stage, and the C=C structure begins to take part in the reaction and release the gas products at the combustion stage.
【學(xué)位授予單位】：西安科技大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2017
【分類號】：TD752.2
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本文編號：1903283