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自燃煤低温氧化放热性实验研究

Experiment Research on Oxidation and Heat Liberation Characteristic of Spontaneous Combustion of Coal at Low Temperature

【作者】 李莉

【导师】 徐精彩;

【作者基本信息】 西安科技大学 , 安全技术及工程, 2004, 硕士

【摘要】 煤层自燃严重影响着煤炭工业发展,给矿井生产带来极大安全隐患。由于实际条件下的煤自燃过程很难描述清楚,使得煤层自然发火预测预报技术的发展受到严重制约。因此,了解煤自燃的条件、发展过程的影响因素对煤层自然发火防治具有重要的理论和工程应用价值。本文根据煤自燃是由于煤样复合放出热量引起的机理,研究涉及的两个关键因素:(1)煤氧复合(2)放出热量,采用理论、实验相结合的研究方法,对自燃煤低温氧化放热性进行研究。通过自然发火实验与程序升温实验以及一系列热重实验分析可得出煤自燃过程中的五个特征温度,在临界温度时煤的失重速率达到最大值,小于临界温度时 ,随煤温升高,煤体氧化放热强度、CO产生率、耗氧速度和升温速度增加缓慢,超过临界温度后,增速加快;超过干裂温度后,急剧增加。通过煤热重动力学参数测定,计算出煤的活化能,了解自燃煤由初始稳定状态变为活化分子所吸收的能量,从本质上描述煤的着火性能。通过煤自燃过程数学模型,确定出煤自燃过程数值模拟所需的关键参数为煤的耗氧速度和放热强度及松散煤体内的氧气扩散系数和渗透系数,通过实验对其进行了研究和测试。提出了实际条件下煤体放热强度和耗氧速度的计算方法。 通过模拟试验的测试,可分析得出煤的实验最短发火期以及表征煤自燃极限外界条件的参数:下限氧浓度、上限漏风强度和最小浮煤厚度。通过研究煤自燃低温氧化放热性,了解煤自燃的发生及发展过程。

【Abstract】 Coal is rich and the first energy resource in China. But spontaneous fires of coal often take place in the coal field outcrops, coal pile and coal mines, which results in a lot of coal lost and the air polluted. Spontaneous combustion of coal is becoming to one of the main disaster along with the development of the fully mechanized long-wall top-coal caving technology in the 90’s.Therefore, it’s important to study the proess of spontaneous combustion of coal . According to the mathematical the model, oxygen consumption rate and heat liberation intensity of coal, diffusion coefficient and osmotic coefficient of oxygen is confirmed for keyparameter to numerical simulation of spontaneous combustion of coal process, and these parameters are researched and test by experiment. The calculation method of oxygen consumption rate and heat liberation intensity is put forward on actual condition.Through the analysis of the thermal gravity investigation, we have known there are five key point of temperature in the process of spontaneous combustion of coal .We can calculate activation energy.Through the analysis of the simulation experiment, we can know the Period of coal spontaneous combustion, heat liberation intensity; oxygen consumption velocity and so on.

  • 【分类号】TQ533
  • 【被引频次】16
  • 【下载频次】522
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