Experimental Investigation on the Abnormal Measurement of Gas Pressure during Canister Desorption of Coal Cuttings

Abstract

Accurate measurement of gas pressure during canister desorption of coal cuttings is an important foundation to prevent coal gas dynamic hazards and determine gas content of coal by volumetric method. It was a new finding that gas pressure in the insulation canister increased and then decreased during the initial desorption stage in the field test, which was different with common sense about gas desorption law. We took a series of experiments to explore the possible reason for this in the laboratory. The experimental results have shown the abnormal measurement of gas pressure was caused by the temperature decrease induced by adsorbing the heat and less external energy during canister desorption. The test condition was a key factor to accurate measurement of gas pressure in the canister. These findings offered insight into the temperature variation and also changed our understanding of the temperature effect on the gas pressure measurement during canister desorption of coal cuttings. The temperature variations induced by the adsorbed gas desorption should be taken into account in engineering application, especially the accurate measurement was applied for the initial stage of gas desorption.