Experimental Study On The Correlation Of Coal Spontaneous Combustion Index Gas

In addition to Shanghai in the Chinese area,other provinces and autonomous regions are more or less distributed coal resources,coal as China’s basic energy,which accounts for about 70% of non-renewable energy.However,coal mining and storage process is often accompanied by coal spontaneous combustion,coal spontaneous combustion is a natural disaster in China,one of the more serious disasters,not only will lead to waste of coal resources,and more serious is to bring mine workers fatal Sexual accident,so the prevention and control of coal spontaneous combustion is particularly important.The long-term practice seems to do early prediction is a key step in the prevention and control of coal spontaneous combustion,coal spontaneous combustion process will produce a series of gas,according to the concentration of these generated gas changes inthe law to reflect the coal spontaneous combustion of the stage for forecasting.It can be seen that the core of the early prediction of coal spontaneous combustion is to determine the appropriate indicator gas for forecasting.In this paper,three different types of metamorphic coal are selected as experimental objects,namely,lignite,long flame coal and gas coal,which are low-grade coal with low metamorphism,because China’s low-order coal reserves are the majority,The spontaneous combustion characteristics of coal are more practical.The selected coal samples are Ximeng（XM）lignite,Shendong（SD）long flame coal,Bailu（BL）long flame coal,Luning（LN）gas coal.The first part of the experiment is to carry out the programmed temperature oxidation experiment on 4 coal samples respectively.Through the analysis of the experimental data,the horizontal comparison of the same kind of coal and the longitudinal comparison of the same gas to obtain a single correlation index gas with temperature changes,Properly deal with the introduction of composite index gas concentration and temperature correlation,through the curve changes in the coal sample of the indicators of gas types.In the experimental part,the heat and differential thermal analysis techniques of each coal sample are used to study the thermalchange in the spontaneous combustion process,and then the coal spontaneous combustion stage is determined.Finally,the method of gray slope correlation theory is used to optimize the stage of accelerating oxidation stage with the stage of thermogravimetric-differential thermal analysis.The main conclusions drawn in this paper are as follows:（1）In the single index gas,CO,H₂,C₂H₄ and C₂H₂ show the regular exponential growth with the temperature change during the heating process,so they can be used as the indicator gas for the early prediction and prediction of the experimental coal sample.The C₂H₆ can be used as the spontaneous combustion index gas of lignite and long flame coal to carry out the relevant forecast and forecast,and can not be used as the gas for spontaneous combustion of gas.（2）The first and second fire coefficients show regularity with the increase of coal temperature,which can reflect the degree of coal spontaneous combustion to some extent,so it can be used as the spontaneous combustion index gas of coal sample to carry out the relevant forecast and forecast.The third fire coefficient During the low temperature oxidation of coal,there are two mutations,which have a large fluctuation.Therefore,it is not appropriate to forecast the spontaneous combustion index gas ascoal samples.（3）For lignite and long flame coal,the alkane ratio ratio of more than 0.15 should be timely warning,so the alkane ratio can be used as lignite and long flame coal index gas,and can not be used as the index of gas gas;Ash ratio and scarcity ratio may be appropriate as a low-grade coal auxiliary indicators to predict and forecast.（4）The change of coal sample quality in the whole oxidation process showed the following trend: the first decrease and then the increase,and then the sharp decline finally stabilized;the heat change showed the first increase and then the lower and then the trend The In the oxygenation stage,the four kinds of coal samples corresponding to the T2 = 294.4 320.6 ℃,in the coal heat decomposition stage,four kinds of coal samples corresponding to the T3 = 300.8 342.8 ℃,in the combustion stage,in addition to LN coal samples at 700 ℃ has not burned,the other three kinds of coal samples corresponding to the T4 578.5 623.4 ℃.（5）Through the comprehensive comparison,this paper chooses the gray slope correlation model to carry on the quantitative analysis,and obtains the comprehensive index forecasting system of Ximeng lignite in the accelerated oxidation stage ofcoal spontaneous combustion as follows: and as the main index gas,The pollution index R1 is the auxiliary index gas;Shendong long flame coal comprehensive index forecasting system is as follows: C₂H₆,and as the main index gas,with R2,C₂H₆ / CH₄ as the auxiliary index gas;Bailu long flame coal comprehensive forecast system is as follows: C₂H₆ / CH₄,R2 and as the main index gas,to C₂H₆ as the auxiliary index gas;Luning gas coal comprehensive index prediction system as follows: R2 and as the main indicator of the gas to CO,as the auxiliary indicator gas.（6）The pyrolysis products of coal are closely related to the types of coal.When selecting the index gas,it is necessary to carry out the experiment on the basis of the experiment.It is appropriate to use a variety of indicators.