可燃粉塵熱解動(dòng)力學(xué)及陰燃過程模型研究
發(fā)布時(shí)間：2018-07-29 15:54
【摘要】：可燃粉塵火災(zāi)或者爆炸事故常會(huì)造成嚴(yán)重的人員傷亡和財(cái)產(chǎn)損失,甚至導(dǎo)致災(zāi)難性的后果,由陰燃引起的粉塵火災(zāi)與爆炸事故日益頻繁。由于陰燃過程的復(fù)雜性,目前對(duì)粉塵陰燃過程及粉塵陰燃機(jī)理的研究不多,對(duì)可燃粉塵陰燃熱解動(dòng)力學(xué)的研究對(duì)于預(yù)防和控制由陰燃引發(fā)的火災(zāi)以及粉塵爆炸事故具有重要的理論意義和應(yīng)用價(jià)值。本文研究了石松子粉、玉米淀粉和煤粉惰性氣氛下的熱解特性,以及空氣環(huán)境下熱解產(chǎn)物(焦炭)的氧化特性,并分析計(jì)算石松子粉的氧化動(dòng)力學(xué)參數(shù)；研究了熱表面上粉塵陰燃過程以及粉塵厚度和熱表面溫度對(duì)陰燃過程的影響；采用三步反應(yīng)動(dòng)力學(xué)機(jī)理建立了粉塵陰燃模型并進(jìn)行了數(shù)值模擬。 本文進(jìn)行了以下三方面的研究工作： (1)粉塵熱反應(yīng)動(dòng)力學(xué)實(shí)驗(yàn)研究 首先在高純氬氣氣氛下對(duì)石松子粉、玉米淀粉以及煤粉進(jìn)行熱重分析實(shí)驗(yàn),從實(shí)驗(yàn)獲取粉塵熱重隨溫度變化曲線。將粉塵在惰性氣氛下的熱解過程分為三個(gè)階段,分析了三種不同粉塵各個(gè)熱解階段的熱解特性。 其次進(jìn)行了空氣氣氛下三種粉塵熱解產(chǎn)物(焦炭)的氧化特性實(shí)驗(yàn)。采用單個(gè)掃描速率法對(duì)DSC曲線進(jìn)行了動(dòng)力學(xué)分析,并獲取了三種粉塵熱解產(chǎn)物的氧化動(dòng)力學(xué)方程：石松子粉玉米淀粉煤粉 采用Friedman-Reich-Levi法與Flynn-Wall-Ozawa法分析計(jì)算了石松子粉塵氧化動(dòng)力學(xué)參數(shù),計(jì)算結(jié)果表明石松子粉在轉(zhuǎn)化率為0.1-0.9之間的表觀活化能并不是固定不變的,而是處于70～115kJ/mol這個(gè)范圍內(nèi)。隨著溫度的升高,轉(zhuǎn)化率增加過程中石松子粉活化能呈遞減趨勢,這表明石松子粉的反應(yīng)活性隨其反應(yīng)率的增加而逐漸增強(qiáng)。 (2)粉塵陰燃過程實(shí)驗(yàn)研究 在粉塵層最低著火溫度測試裝置的基礎(chǔ)上增加了溫度采集系統(tǒng),設(shè)計(jì)了粉塵陰燃過程實(shí)驗(yàn)裝置并進(jìn)行了相關(guān)實(shí)驗(yàn)研究,考察了粉塵厚度以及熱板溫度對(duì)石松子粉塵陰燃過程的影響。 實(shí)驗(yàn)現(xiàn)象表明粉塵在熱表面上陰燃過程包括兩個(gè)階段：陰燃引發(fā)階段和陰燃傳播過程階段。不同厚度石松子粉陰燃過程實(shí)驗(yàn)表明粉塵厚度對(duì)陰燃傳播速率沒有影響,陰燃由粉塵表面向內(nèi)部傳播的過程中,內(nèi)部粉塵受到氧濃度的約束而表現(xiàn)為熱解過程,表面始終具有充裕的氧濃度,因此陰燃區(qū)域首先發(fā)生在表面。不同溫度熱表面陰燃實(shí)驗(yàn)研究表明粉塵陰燃過程的引發(fā)需要一定的外部溫度(25mm厚的石松子粉為200℃)。較高的熱板溫度下粉塵發(fā)生陰燃的時(shí)間較短,但熱表面溫度不影響陰燃由粉塵表面向內(nèi)部的傳播速度。 (3)粉塵陰燃的數(shù)值模擬 采用三步反應(yīng)動(dòng)力學(xué)機(jī)理,基于流體動(dòng)力學(xué)的基本原理,通過理論分析建立了粉塵陰燃模型,采用可燃固體通用熱解模型(Gpyro)軟件及所獲取的粉塵熱解與氧化動(dòng)力學(xué)參數(shù)對(duì)粉塵陰燃過程進(jìn)行了數(shù)值模擬。通過模擬結(jié)果獲得了粉塵陰燃過程中的二維溫度場變化以及各步動(dòng)力學(xué)反應(yīng)的速率變化,模擬結(jié)果與實(shí)驗(yàn)結(jié)果中的各個(gè)采樣點(diǎn)溫度變化基本一致。
[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.
【學(xué)位授予單位】：東北大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2013
【分類號(hào)】：X928.1;X932
本文編號(hào)：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.
【學(xué)位授予單位】：東北大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2013
【分類號(hào)】：X928.1;X932
【參考文獻(xiàn)】
相關(guān)期刊論文 前10條
1 秋珊珊;曹衛(wèi)國;黃麗媛;張建新;潘峰;;石松子粉粉塵爆炸試驗(yàn)研究[J];爆破器材;2012年03期
2 何宏舟,駱仲泱,岑可法;不同熱分析方法求解無煙煤燃燒反應(yīng)動(dòng)力學(xué)參數(shù)的研究[J];動(dòng)力工程;2005年04期
3 郭曉平,解茂昭,孫文策;水平纖維質(zhì)填充床陰燃過程的數(shù)值模擬[J];工程熱物理學(xué)報(bào);2000年05期
4 路長;周建軍;劉乃安;張林鶴;林其釗;王清安;;陰燃材料受熱升溫過程分析[J];工程熱物理學(xué)報(bào);2006年S2期
5 胡榮祖;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 何東波,鄧照帆,鐘圣俊;幾種粉塵層反應(yīng)動(dòng)力學(xué)參數(shù)的研究[J];粉體技術(shù);1997年01期
7 孫文策，解茂昭，張明閣，沙秀芝，，李河;水平燃料床陰燃的傳播及其向明火轉(zhuǎn)捩的實(shí)驗(yàn)研究[J];火災(zāi)科學(xué);1995年S1期
8 王信群;R Klemens;P Wolanski;徐天瑞;;谷物纖維及粉塵陰燃實(shí)驗(yàn)研究[J];糧食與飼料工業(yè);2009年04期
9 任如意;王大尉;;利用活化能研究煤的自燃傾向性[J];煤礦開采;2006年06期
10 鄒學(xué)權(quán),王新紅,武建軍,陳越;用熱重-差熱-紅外光譜技術(shù)研究煤粉的燃燒特性[J];煤炭轉(zhuǎn)化;2003年01期
相關(guān)博士學(xué)位論文 前1條
1 王健;糧食粉塵爆炸的實(shí)驗(yàn)研究與數(shù)值模擬[D];東北大學(xué);2010年
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