可燃粉尘热解动力学及阴燃过程模型研究
发布时间：2018-07-29 15:54
【摘要】：可燃粉尘火灾或者爆炸事故常会造成严重的人员伤亡和财产损失,甚至导致灾难性的后果,由阴燃引起的粉尘火灾与爆炸事故日益频繁。由于阴燃过程的复杂性,目前对粉尘阴燃过程及粉尘阴燃机理的研究不多,对可燃粉尘阴燃热解动力学的研究对于预防和控制由阴燃引发的火灾以及粉尘爆炸事故具有重要的理论意义和应用价值。本文研究了石松子粉、玉米淀粉和煤粉惰性气氛下的热解特性,以及空气环境下热解产物(焦炭)的氧化特性,并分析计算石松子粉的氧化动力学参数；研究了热表面上粉尘阴燃过程以及粉尘厚度和热表面温度对阴燃过程的影响；采用三步反应动力学机理建立了粉尘阴燃模型并进行了数值模拟。 本文进行了以下三方面的研究工作： (1)粉尘热反应动力学实验研究 首先在高纯氩气气氛下对石松子粉、玉米淀粉以及煤粉进行热重分析实验,从实验获取粉尘热重随温度变化曲线。将粉尘在惰性气氛下的热解过程分为三个阶段,分析了三种不同粉尘各个热解阶段的热解特性。 其次进行了空气气氛下三种粉尘热解产物(焦炭)的氧化特性实验。采用单个扫描速率法对DSC曲线进行了动力学分析,并获取了三种粉尘热解产物的氧化动力学方程：石松子粉玉米淀粉煤粉 采用Friedman-Reich-Levi法与Flynn-Wall-Ozawa法分析计算了石松子粉尘氧化动力学参数,计算结果表明石松子粉在转化率为0.1-0.9之间的表观活化能并不是固定不变的,而是处于70～115kJ/mol这个范围内。随着温度的升高,转化率增加过程中石松子粉活化能呈递减趋势,这表明石松子粉的反应活性随其反应率的增加而逐渐增强。 (2)粉尘阴燃过程实验研究 在粉尘层最低着火温度测试装置的基础上增加了温度采集系统,设计了粉尘阴燃过程实验装置并进行了相关实验研究,考察了粉尘厚度以及热板温度对石松子粉尘阴燃过程的影响。 实验现象表明粉尘在热表面上阴燃过程包括两个阶段：阴燃引发阶段和阴燃传播过程阶段。不同厚度石松子粉阴燃过程实验表明粉尘厚度对阴燃传播速率没有影响,阴燃由粉尘表面向内部传播的过程中,内部粉尘受到氧浓度的约束而表现为热解过程,表面始终具有充裕的氧浓度,因此阴燃区域首先发生在表面。不同温度热表面阴燃实验研究表明粉尘阴燃过程的引发需要一定的外部温度(25mm厚的石松子粉为200℃)。较高的热板温度下粉尘发生阴燃的时间较短,但热表面温度不影响阴燃由粉尘表面向内部的传播速度。 (3)粉尘阴燃的数值模拟 采用三步反应动力学机理,基于流体动力学的基本原理,通过理论分析建立了粉尘阴燃模型,采用可燃固体通用热解模型(Gpyro)软件及所获取的粉尘热解与氧化动力学参数对粉尘阴燃过程进行了数值模拟。通过模拟结果获得了粉尘阴燃过程中的二维温度场变化以及各步动力学反应的速率变化,模拟结果与实验结果中的各个采样点温度变化基本一致。
[Abstract]:The fire and explosion accidents of combustible dust often cause serious casualties and property losses, and even cause catastrophic consequences. The dust fires and explosions caused by the smoldering are increasingly frequent. Due to the complexity of the process of the smoldering, the research on the process of dust smoldering and the mechanism of dust smoldering is not much, and the pyrolysis of combustible dust smoldering The study of mechanics has important theoretical significance and application value for preventing and controlling the fire caused by smoldering and dust explosion. This paper studies the pyrolysis characteristics of Ishimatsu Ko powder, corn starch and pulverized coal inert atmosphere, as well as the oxidation characteristics of the pyrolysis products (coke) in the air environment, and analyses and calculates the oxygen of the stone pine powder. The kinetic parameters are changed. The effect of dust smoldering on the hot surface and the effect of dust thickness and thermal surface temperature on the process of smoldering is studied. The model of dust smoldering is established by using the three step reaction kinetics mechanism and the numerical simulation is carried out.
This article has carried out the following three aspects of research work:
(1) experimental study on thermal reaction kinetics of dust
At first, the thermogravimetric analysis of Ishimatsu Ko powder, corn starch and pulverized coal was carried out in high pure argon atmosphere. The curves of thermal weight of dust were obtained from the experiment. The pyrolysis process of dust in the inert atmosphere was divided into three stages, and the pyrolysis characteristics of each stage of three different kinds of dust were analyzed.
Secondly, the oxidation characteristic experiment of three kinds of dust pyrolysis products (Jiao Tan) was carried out in air atmosphere. The kinetic analysis of the DSC curve was carried out by single scanning rate method, and the kinetic equation of oxidation of three kinds of dust pyrolysis products was obtained.
The kinetic parameters of Ishimatsu Ko dust oxidation were calculated by Friedman-Reich-Levi method and Flynn-Wall-Ozawa method. The results showed that the apparent activation energy of the stone pine powder in the conversion rate of 0.1-0.9 was not fixed, but in the range of 70 ~ 115kJ/mol. With the increase of temperature, the transformation rate increased in the process of stone pine. The activation energy of the seed meal showed a decreasing trend, indicating that the reactivity of stone pine seed powder increased with the increase of its reaction rate.
(2) experimental study on the process of dust smoldering
The temperature collection system was added on the basis of the test device for the minimum ignition temperature of the dust layer. The experimental device was designed and the experimental research was carried out. The influence of the thickness of the dust and the temperature of the hot plate on the Ishimatsu Ko dust combustion process was investigated.
The experimental phenomenon shows that the process of the dust on the hot surface consists of two stages: the stage of the priming of the smoldering and the stage of the spread of the smoldering. The experiment of the smoldering process of the powder of different thickness of the pine nut powder shows that the thickness of the dust has no effect on the spread rate of the smoldering, and the internal dust is restrained by the oxygen concentration during the process of the smoldering from the dust surface to the interior. In the process of pyrolysis, the surface always has abundant oxygen concentration, so the smoldering area first occurs on the surface. The experimental study of different temperature hot surface smoldering indicates that the initiation of the dust smoldering process requires a certain external temperature (the 25mm thick stone pine powder is 200 c). The surface temperature does not affect the propagation speed of smoldering from the surface of dust to the interior.
(3) numerical simulation of dust smoldering
Based on the basic principle of fluid dynamics, the dust smoldering model was established on the basis of the basic principle of fluid dynamics, and the numerical simulation of the dust smoldering process was carried out by using the Gpyro software and the kinetic parameters of the dust pyrolysis and oxidation. The dust smoldering was obtained by the simulation results. The change of two dimensional temperature field and the rate of kinetic reaction in each step are basically consistent with the temperature changes at various sampling points in the experiment.
【学位授予单位】：东北大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：X928.1;X932
本文编号：2153182
[Abstract]:The fire and explosion accidents of combustible dust often cause serious casualties and property losses, and even cause catastrophic consequences. The dust fires and explosions caused by the smoldering are increasingly frequent. Due to the complexity of the process of the smoldering, the research on the process of dust smoldering and the mechanism of dust smoldering is not much, and the pyrolysis of combustible dust smoldering The study of mechanics has important theoretical significance and application value for preventing and controlling the fire caused by smoldering and dust explosion. This paper studies the pyrolysis characteristics of Ishimatsu Ko powder, corn starch and pulverized coal inert atmosphere, as well as the oxidation characteristics of the pyrolysis products (coke) in the air environment, and analyses and calculates the oxygen of the stone pine powder. The kinetic parameters are changed. The effect of dust smoldering on the hot surface and the effect of dust thickness and thermal surface temperature on the process of smoldering is studied. The model of dust smoldering is established by using the three step reaction kinetics mechanism and the numerical simulation is carried out.
This article has carried out the following three aspects of research work:
(1) experimental study on thermal reaction kinetics of dust
At first, the thermogravimetric analysis of Ishimatsu Ko powder, corn starch and pulverized coal was carried out in high pure argon atmosphere. The curves of thermal weight of dust were obtained from the experiment. The pyrolysis process of dust in the inert atmosphere was divided into three stages, and the pyrolysis characteristics of each stage of three different kinds of dust were analyzed.
Secondly, the oxidation characteristic experiment of three kinds of dust pyrolysis products (Jiao Tan) was carried out in air atmosphere. The kinetic analysis of the DSC curve was carried out by single scanning rate method, and the kinetic equation of oxidation of three kinds of dust pyrolysis products was obtained.
The kinetic parameters of Ishimatsu Ko dust oxidation were calculated by Friedman-Reich-Levi method and Flynn-Wall-Ozawa method. The results showed that the apparent activation energy of the stone pine powder in the conversion rate of 0.1-0.9 was not fixed, but in the range of 70 ~ 115kJ/mol. With the increase of temperature, the transformation rate increased in the process of stone pine. The activation energy of the seed meal showed a decreasing trend, indicating that the reactivity of stone pine seed powder increased with the increase of its reaction rate.
(2) experimental study on the process of dust smoldering
The temperature collection system was added on the basis of the test device for the minimum ignition temperature of the dust layer. The experimental device was designed and the experimental research was carried out. The influence of the thickness of the dust and the temperature of the hot plate on the Ishimatsu Ko dust combustion process was investigated.
The experimental phenomenon shows that the process of the dust on the hot surface consists of two stages: the stage of the priming of the smoldering and the stage of the spread of the smoldering. The experiment of the smoldering process of the powder of different thickness of the pine nut powder shows that the thickness of the dust has no effect on the spread rate of the smoldering, and the internal dust is restrained by the oxygen concentration during the process of the smoldering from the dust surface to the interior. In the process of pyrolysis, the surface always has abundant oxygen concentration, so the smoldering area first occurs on the surface. The experimental study of different temperature hot surface smoldering indicates that the initiation of the dust smoldering process requires a certain external temperature (the 25mm thick stone pine powder is 200 c). The surface temperature does not affect the propagation speed of smoldering from the surface of dust to the interior.
(3) numerical simulation of dust smoldering
Based on the basic principle of fluid dynamics, the dust smoldering model was established on the basis of the basic principle of fluid dynamics, and the numerical simulation of the dust smoldering process was carried out by using the Gpyro software and the kinetic parameters of the dust pyrolysis and oxidation. The dust smoldering was obtained by the simulation results. The change of two dimensional temperature field and the rate of kinetic reaction in each step are basically consistent with the temperature changes at various sampling points in the experiment.
【学位授予单位】：东北大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：X928.1;X932
【参考文献】
相关期刊论文 前10条
1 秋珊珊;曹卫国;黄丽媛;张建新;潘峰;;石松子粉粉尘爆炸试验研究[J];爆破器材;2012年03期
2 何宏舟,骆仲泱,岑可法;不同热分析方法求解无烟煤燃烧反应动力学参数的研究[J];动力工程;2005年04期
3 郭晓平,解茂昭,孙文策;水平纤维质填充床阴燃过程的数值模拟[J];工程热物理学报;2000年05期
4 路长;周建军;刘乃安;张林鹤;林其钊;王清安;;阴燃材料受热升温过程分析[J];工程热物理学报;2006年S2期
5 胡荣祖;ESTIMATION OF THE CRITICAL RATE OF TEMPERATURE INCREASE OF THERMAL EXPLOSION OF NITROCELLULOSE USING NON-ISOTHERMAL DSC[J];Chinese Journal of Polymer Science;2003年03期
6 何东波,邓照帆,钟圣俊;几种粉尘层反应动力学参数的研究[J];粉体技术;1997年01期
7 孙文策，解茂昭，张明阁，沙秀芝，，李河;水平燃料床阴燃的传播及其向明火转捩的实验研究[J];火灾科学;1995年S1期
8 王信群;R Klemens;P Wolanski;徐天瑞;;谷物纤维及粉尘阴燃实验研究[J];粮食与饲料工业;2009年04期
9 任如意;王大尉;;利用活化能研究煤的自燃倾向性[J];煤矿开采;2006年06期
10 邹学权,王新红,武建军,陈越;用热重-差热-红外光谱技术研究煤粉的燃烧特性[J];煤炭转化;2003年01期
相关博士学位论文 前1条
1 王健;粮食粉尘爆炸的实验研究与数值模拟[D];东北大学;2010年
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