Method for determining air-leakage rate of oxidized zone of goaf

Abstract

The invention relates to a method for determining air-leakage rate of an oxidized zone of goaf, and belongs to the technical field of coal mine downhole spontaneous combustion disaster prevention. The method includes firstly, determining nitrogen injection flow rate; secondly, burying beam tubes for gas component measurement in the goaf to determine change of concentration of oxygen; thirdly, establishing a numerical computing module, and determining concentration distribution of oxygen in the goaf and the air-leakage rate on the condition without nitrogen injection by a numerical simulation process; fourthly, performing a thermogravimetric experiment to coal samples sampled from the work face, acquiring oxygen concentration on the condition without weight gaining, and serving the oxygen concentration as an inerting fireproof index of the goaf; fifthly, dividing the spontaneous combustion three-zone of the goaf; sixthly, selecting the widest section of the oxidized zone in the goaf, simulating dividing results of the spontaneous combustion three-zone of the goaf to determine the boundary according to a fitted equation of field real-time measured oxygen concentration distribution results, and solving the average oxygen concentration of the section in the oxidized zone; seventhly, determining nitrogen purity in an actual nitrogen injection process of the work face; and eighthly, determining the air-leakage rate of the oxidized zone of the goaf according to a nitrogen injection quantity calculation formula.

Description

technical field [0001] The invention belongs to the technical field of prevention and control of coal spontaneous combustion disasters in underground coal mines, and in particular relates to a method for determining the air leakage volume of an oxidation zone in a goaf, which is mainly used for the prevention and control of spontaneous combustion of residual coal in the goaf of a coal mine mining face. Background technique [0002] Coal spontaneous combustion disaster is one of the main disasters in coal mines. Coal spontaneous combustion not only burns valuable resources, but also produces a large amount of CO, CO 2 and SO 2 Toxic and harmful gases, such as toxic and harmful gases, endanger the health and life of workers and pollute the environment; they can also induce gas and coal dust explosion accidents, which are major disasters that hinder the safe production of coal mines. Among them, the spontaneous combustion of coal in the goaf is more harmful because of its stro...

AI Technical Summary

Problems solved by technology

However, due to the complexity and concealment of the goaf and the irregularity of the three spontaneous combustion zones, it is very difficult to determine the air leakage in the goaf oxidation spontaneous combustion zone. The traditional method is to obtain the air supply volume of the working face based on experience 0.5% to 1% of the total, lack of scientific basis

For the key influencing factor of coal sp

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