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Simulation of Spontaneous Combustion of Coal and the Critical Conditions Leading to Ignition

Author: SunZongXian
Tutor: WangShuGang
School: Dalian University of Technology
Course: Heating,Gas Supply, Ventilation and Air Conditioning Engineering
Keywords: Mine Spontaneous combustion of coal Experimental test Numerical Simulation Critical fire conditions
CLC: TD752.2
Type: Master's thesis
Year: 2010
Downloads: 197
Quote: 0
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Abstract


The spontaneous combustion of coal is caused by a mine fire and one of the main factors of the coal fire in the storage and transportation process, often resulting in casualties and the loss of state property. As coal natural fire accident hazards of coal mine safety as gas and coal dust explosions and other accidents, and has become one of the major factors restricting the coal mine production safety. The spontaneous combustion of coal is formed only in some ventilation, oxygen, and heat storage critical conditions under which it will occur, and thus to study the the coal natural fire process as well as coal fire critical condition with a great academic and practical value. This paper aims to use a combination of experimental tests and numerical simulation methods to study the spontaneous combustion of coal occurs, the development process, and thus predict coal spontaneous combustion time under certain conditions, and simulation analysis of critical fire conditions for spontaneous combustion of coal. Proceed by the experimental study, the to build auxiliary heat source heating conditions of coal spontaneous combustion experiment device, the low-temperature oxidation of the analog coal crushing under aerobic conditions during the heating process. Based on the experimental results, the spontaneous combustion of coal is divided into two distinct phases of coal oxygen chemical adsorption process and the chemical reaction process, respectively, obtained by fitting the rate of oxygen consumption of coal the oxygen chemical adsorption and chemical reaction stage segment mathematical expressions. And numerical simulation as a means of using the rate of oxygen consumption of the different stages of oxidation from fitting the experiment to establish the the unsteady prediction model describing the process of coal spontaneous combustion, according to the porous medium heat and mass transfer theory. The model considered the the loose coal vivo seepage velocity field distribution, the distribution pattern of the interaction of temperature and oxygen concentration in coal and oxygen, moisture and other factors are ignored on the spontaneous combustion of coal. Finally, using the established mathematical model calculate the experimental coal sample spontaneous combustion process in a variety of operating conditions, the comparative analysis of different coal porosity and wind speed for wind and other factors on the spontaneous combustion of coal to determine the experimental The apparatus of coal ignition critical conditions. From the comparative analysis of numerical simulation and experimental test results, both showed good consistency. In good agreement with values ??predicted experimental coal sample spontaneous combustion time of 38 days 45 days of actual fire and mine site. This shows that the low temperature coal oxidation process is divided into two different stages of the chemisorption process of coal oxidation and chemical reaction process has a certain rationality. Simulation determined critical fire conditions applicable in the present experimental apparatus: coal porosity of 0.3 to 0.4, for the wind velocity 0.0001 ~ 0.0003m / s.

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CLC: > Industrial Technology > Mining Engineering > Mine safety and labor protection > Mine fire > Mine Fire > Internal fire and prevention
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