内蒙古褐煤热解特性及半焦燃烧特性试验研究

发布时间：2018-05-05 02:41

本文选题：内蒙褐煤 + 低温热解　；参考：《内蒙古工业大学》2015年硕士论文

【摘要】：随着经济发展和社会进步,能源消费结构不合理的问题在我国可持续发展的路上越来越凸显。面对日益增加的能源与环境压力,我国能源结构改革势在必行。我国长期以煤炭作为主要能源,以往在对煤炭资源的使用过程中,始终优先利用高品质煤。但随着我国经济的飞速发展,煤炭需求量不断增加,高品质煤在我国的供应日趋紧张。我国的低阶煤储量巨大,大量低阶煤难以利用,所以低阶煤的利用日益受到重视。实现低阶煤的清洁高效利用,对缓解能源供应紧张,改革我国能源结构具有重要意义。本文首先对内蒙地区的胜利煤田、霍林河煤矿和白音华煤矿三个产地的褐煤进行工业分析、元素分析,并进行初步对比。结果表明,三种褐煤的内水分含量相差不大,都小于20%,其中胜利褐煤水分含量最低;三种褐煤挥发分含量较大,都在35%左右;三种褐煤含氧量都较高,与其结合的C、H也相对较高。因此内蒙古地区褐煤有较大的提质空间。其次采用热重法研究不同粒度、不同升温速率对褐煤热解特性的影响。结果表明,褐煤的热解大致可分为脱水干燥、挥发分析出及有机物分解和成焦三个阶段。通常粒径越小、升温速率越低,热解越完全,挥发分析出温度和最大失重率对应温度也越低。然后采用热重-傅立叶红外联用方法对褐煤热解析出产物进行分析,总结其热解规律。结果表明,褐煤的热解产物较为复杂,不同褐煤的热解产物组成基本相同。褐煤热解的主要不凝结气体为SO2,NH3,CO2,CH4,CO。热解油的主要成分有烯烃、脂肪烃、多环芳烃、单环芳烃、醇、酚类化合物、酮、酯、羧酸类、酰胺类、含氧化合物、氮磷化合物、硫化合物、亚硝酸酯化合物、卤素化合物等。最后将三种褐煤在不同终温下制成半焦,在对其进行基本分析对比后,采用热重法研究热解终温对其燃烧特性的影响。对半焦燃烧的燃烧特征判别指数的计算结果表明,随热解终温的升高,半焦的稳定性升高。利用Coast-Redfern积分法对三种褐煤及其半焦进行燃烧动力学分析,结果表明当反应级数取1.5时,动力学拟合相关系数R的取值在0.99以上,拟合准确。随制备半焦的热解温度升高,半焦的活化能越来越大,这与对其工业分析、元素分析、燃烧特征指数分析得出的结论一致。经过热解提质,褐煤转化为低含水率、高发热量的燃料,呈现出由低阶煤向高阶煤转变的趋势。
[Abstract]:With the development of economy and society, the problem of unreasonable energy consumption structure is more and more prominent on the way of sustainable development. Facing the increasing pressure of energy and environment, the reform of energy structure is imperative. Coal is the main energy in China for a long time. In the past, high quality coal has always been given priority in the use of coal resources. However, with the rapid development of economy in China, the demand for coal is increasing, and the supply of high quality coal in China is becoming increasingly tight. Because of the huge reserves of low-rank coal in China, a large number of low-rank coal is difficult to use, so the utilization of low-rank coal has been paid more and more attention. The realization of clean and efficient utilization of low rank coal is of great significance to alleviate the shortage of energy supply and to reform the energy structure of our country. In this paper, the lignite from Shengli coalfield, Huolinhe coal mine and Baiyinhua coal mine in Inner Mongolia are analyzed and compared. The results show that the internal moisture content of the three lignite is not different, which is less than 20%, the moisture content of Shengli lignite is the lowest, the volatile content of the three lignite is about 35%, and the oxygen content of the three lignite is high. The Con H associated with it is also relatively high. Therefore, the lignite in Inner Mongolia region has a large room for quality improvement. Secondly, the effect of different particle size and heating rate on pyrolysis characteristics of lignite was studied by thermogravimetry. The results show that the pyrolysis of lignite can be divided into three stages: dehydration and drying, volatilization analysis and decomposition and coking of organic matter. Usually, the smaller the particle size, the lower the heating rate, the more complete the pyrolysis, and the lower the corresponding temperature between the volatilization analysis temperature and the maximum weight loss rate. Then the thermogravimetric Fourier transform infrared (FTIR) method was used to analyze the pyrolysis of lignite. The results show that the pyrolysis products of lignite are more complex and the composition of pyrolysis products of different lignite is basically the same. The main uncondensed gas for pyrolysis of lignite is so _ 2H _ 3H _ 2CO _ 2H _ 4C _ 4. The main components of pyrolytic oil are olefins, aliphatic hydrocarbons, polycyclic aromatic hydrocarbons, monocyclic aromatic hydrocarbons, alcohols, phenolic compounds, ketones, esters, carboxylic acids, amides, oxygen-containing compounds, nitrogen and phosphorus compounds, sulfur compounds, nitrite compounds, Halogen compounds, etc. Finally, three kinds of lignite were made into semi-char at different final temperatures. After the basic analysis and comparison, the effect of final pyrolysis temperature on combustion characteristics was studied by thermogravimetric method. The calculation results of combustion characteristic discriminant index of semi-coke combustion show that the stability of semi-coke increases with the increase of final pyrolysis temperature. The combustion kinetics of three kinds of lignite and its char were analyzed by Coast-Redfern integration method. The results show that the correlation coefficient R of kinetic fitting is more than 0.99 when the reaction order is 1.5, and the fitting is accurate. The activation energy of semi-coke increases with the increase of pyrolysis temperature, which is consistent with the analysis of industrial analysis, elemental analysis and combustion characteristic index. After pyrolysis, lignite is transformed into a fuel with low moisture content and high calorific value, which shows a tendency from low-rank coal to high-order coal.
【学位授予单位】：内蒙古工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TD849.2

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