Method and device for measuring expansion energy of initially released gas from coal samples

Abstract

The invention provides a method and a device for measuring expansion energy of initial releasing gas of a coal sample. The device comprises a coal sample tank, a gradually reducing nozzle, a ball valve, a photoelectric switch, a temperature sensor, a pressure sensor, an electromagnetic valve and the like; before testing, a coal sample or an iron block is placed into the coal sample tank, the ball valve is switched off, the coal sample tank is filled with gas after vacuumized, and adsorption equilibrium of the coal sample tank is realized under pressure and temperature of original coal seam gas; during testing, the ball valve is switched on by a pneumatic valve, the gas in the coal sample tank rushes out of the gradually reducing nozzle rapidly, and at the same time, a computer is started to collect data until the pressure of the gas in the coal sample tank is reduced to zero; substitution of the sound velocity conductance and the critical pressure ratio of the gradually reducing nozzle is performed, test data of the coal sample and the iron block are processed, two gas expansion energy curves are obtained respectively, and the two cures are subtracted to obtain one expansion energy curve of the gas rushing out of the coal sample; integration of the gas expansion energy is performed, the coal sample weight is divided by the integration, and the expansion energy of initial releasing gas of the coal sample can be obtained; according to the method and the device, the structure is simple, the use is convenient, and the testing is accurate and reliable.

Description

technical field [0001] The invention relates to a method and a device for measuring the expansion energy of initially released gas from a coal sample, which are used for judging the outburst risk of coal seams, and belong to the technical field of coal mine disaster prediction. Background technique [0002] As we all know, the commonly used methods for predicting the dynamic phenomenon of coal unraveling in Shimen are the comprehensive index method and the cuttings gas desorption index method, which mainly measure the gas pressure of the coal seam, the firmness coefficient of the coal sample, the initial velocity of gas release or the cuttings desorption index K1 and Δh 2 . These methods have certain reference value. But its shortcoming is that they are the product of people's understanding of the salient process is still in the empirical stage, the accuracy is not high, and the error is too large. In addition, the critical value of predicted outburst risk should be deter...

AI Technical Summary

Problems solved by technology

But its shortcomings are: they are the products of people's understanding of the salient process is still in the empirical stage, the accuracy is not high, and the error is too large

When calculating the coal sample and the gas expansion energy curve of the tapered spout under the condition of the same volume of iron block, a fixed spout cross-sectional area is used, resulting in the initial release of gas gushing from the coal sample after the subtraction of the two There is a certain error in the expansion energy, especially the data in the subcritical stage are greatly affected

In addition, since the data of the coal sample and the iron block should be measured separately during the measurement process, the gas expansion energy curves gushing from the tapered spout in the two cases are calculated, and the gas expansion energy curve gushing from the coal sample is obtained after subtraction. Therefore, it is also very important to ensure that the starting point of the calculation curve is unified, and a small period of time will cause a large error

Since the determination of the initially released gas expansion energy of the coal sample is mainly used to judge the outburst risk of the measured coal seam, errors in the calculation method and errors caused by the calculation starting point may lead to misjudgment and accidents, so the existing measurement method is improved , it is necessary to improve the measurement accuracy of initially released gas expansion energy of coal samples

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