煤自燃指标气体生成特性及内在规律性研究

发布时间：2018-01-18 00:27

  本文关键词：煤自燃指标气体生成特性及内在规律性研究　出处：《太原理工大学》2017年硕士论文　论文类型：学位论文

  更多相关文章： 煤自燃 指标气体 内在规律 预测预报 灰色关联

【摘要】：长久以来,煤自燃不仅制约着矿井安全生产工作,而且浪费宝贵的煤炭资源,煤自燃预测预报对及时治理煤自燃有指导意义。煤自热过程中产生的指标气体在煤自燃预测预报工作中具有重要作用,在此基础上本文通过对指标气体生成规律及其内在关系的研究,探索煤自燃机理,目的是给预测和治理煤自燃提供理论依据,增加指标气体的应用价值。本文选取自燃倾向性不同的锡盟褐煤、神东长焰煤和义马气煤三种不同变质程度的煤作为研究对象。采用程序升温氧化和恒温氧化的实验方法,研究在不同煤化程度、温度、粒径、质量和反应体积条件下煤自燃过程中指标气体H_2、CO、CO_2和C_2H_4的释放规律。同时以灰色关联理论和多元线性回归模型,探讨指标气体之间的内在关联性。得出以下结论:(1)在煤自燃过程中,H_2与C_2H_4的释放规律相似,随着温度的升高,它们的生成量呈指数型增长,适合作为指标气体。(2)在煤自燃过程中,煤在30℃条件下就开始吸收O_2生成CO和CO_2等气体。随着温度的升高CO与CO_2的生成量均呈现指数型增长。在恒温氧化过程中,较低温度条件下CO生成量随反应时间的增长符合“S”型的逻辑斯蒂增长模型,而在较高温度下呈现出对数型增长趋势。对于不同煤种,两种不同增长模型发生转变的临界温度为:褐煤100℃、长焰煤120℃、气煤120℃。在自燃过程中,CO_2的生成量随时间的变化呈对数型增长,CO_2的生成规律不随温度变化。(3)在恒温氧化过程中,CO_2和CO生成速率的比值在不同温度条件下是稳定的数值。这一比值受煤种特性和供氧条件的影响。当氧气不足时的比值大于氧气充足时的比值。说明当氧气减小时,CO对氧气的变化更为敏感,即CO的生成过程中氧气具有明显的促进作用。CO_2对氧气的不敏感说明了CO_2的生成不只来源于煤氧结合,部分来自于煤内部含氧官能团(如羧基)等中间络合物的分解。(4)通过对各种指标气体生成规律的研究,发现H_2、CH_4、C_2H_4、C_2H_6和CO_2的生成之间有紧密的协同性。运用灰色关联分析方法得到指标气体之间的关联度,将生成规律与关联度相结合对指标气体进行分类:(1)H_2、C_2H_4、CO_2;(2)CO、CO_2;(3)CH_4、C_2H_4、C_2H_6。三种指标气体体系的分类中重复的指标气体表明了部分指标气体的生成途径不唯一,表明煤自燃过程中存在着多种反应序列。(5)运用多元线性回归模型,对关联紧密的指标气体进行拟合,得到它们之间的数学关系。通过分析计算发现:C_2H_4的生成对CO_2的生成呈促进作用;H_2的生成和O_2的消耗在不同条件下对CO_2的生成分为促进作用与抑制作用两种。
[Abstract]:For a long time, coal spontaneous combustion has not only restricted the safety of mine production, but also wasted valuable coal resources. The prediction and prediction of coal spontaneous combustion is of guiding significance for the timely control of coal spontaneous combustion. The index gas produced in the process of coal spontaneous heating plays an important role in the prediction and prediction of coal spontaneous combustion. On this basis, through the study of the law of index gas generation and its internal relations, this paper explores the mechanism of coal spontaneous combustion, in order to provide a theoretical basis for the prediction and treatment of coal spontaneous combustion. In this paper, Ximeng lignite with different spontaneous combustion tendency is selected. Three kinds of coal with different metamorphism degree were used as the research object. The experimental methods of programmed temperature oxidation and constant temperature oxidation were used to study the coalification degree, temperature and particle size. The release law of index gases H _ 2CO _ 2 and C _ 2H _ 4 in the process of coal spontaneous combustion under the condition of mass and reaction volume. At the same time, the grey correlation theory and multivariate linear regression model are used. The following conclusion is drawn: (1) in the process of spontaneous combustion of coal, the release regularity of H _ (2) and C _ 2H _ (4) is similar to that of C _ 2H _ (4), with the increase of temperature. It is suitable to be used as an index gas in the process of coal spontaneous combustion. At 30 鈩，

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