Determination method of oxidation heat liberation intensity of loose coal

Abstract

Provided is a determination method of oxidation heat liberation intensity of loose coal. Oxidation heat qic and conductivity factor lambada of loose coal are measured accurately based on the internal rule of heat and mass transfer of loose coal. The heat wire is placed at the center of the loose coal as the heat source and temperature measurement points and gas collection points are arranged inside the loose coal. The screened loose coal samples are loaded into a cylindrical heat insulation reaction container after the density and voidage thereof being measured. First, the loose coal samples are put in nitrogen atmosphere and heated until the temperature thereof reaches the predetermined value. Then the samples are left to cool naturally. The temperatures of temperature measurement points are collected continuously. Conductivity factor lambada of loose coal samples at different temperatures are calculated by the value of the factors of temperature, time, density, specific heat capacity and voidage. Then air is fed into the coal samples continuously. The temperatures of temperature measurement points and oxygen concentrations of the samples are monitored continuously during the cooling process. Finally, oxidation heat liberation intensity qic of loose coal samples at different temperatures are calculated by the value of the factors of temperature, conductivity factor, time, density, specific heat capacity, voidage and air flow meter. The experimental time is reduced and the obtained results are more accurate by utilizing the above method. As a result, the method is applicable to the measurement of exothermic process of coals.

Description

technical field [0001] The invention relates to a method for testing the heat of oxidation of loose coal, which is especially suitable for studying the law of heat and mass transfer in the process of spontaneous combustion of coal and accurately testing the heat of oxidation in the process of self-heating of loose coal. Background technique [0002] Coal-oxygen reaction heat release is the main heat source for coal self-heating, and coal oxidation heat is the main index to describe its heat release performance. Only by accurately measuring coal oxidation heat can we understand the oxidation heat release performance of coal, and then Accurately predict coal spontaneous combustion and prevent fire accidents. Therefore, how to measure the low-temperature oxidation heat of coal becomes the key to study the spontaneous combustion characteristics of coal. [0003] Because the low-temperature oxidation process of coal is very slow, the heat released is also very small, especially ...

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Problems solved by technology

The test results of the current large-scale laboratory test method are relatively accurate, but the test period is long, and it is not suitable for the needs of large-scale coal sample testing; the chemical bond energy estimation method is based on the derivation of the coal spontaneous combustion reaction process, but the coal spontaneous combustion process is relatively affected. Affected by many factors, it is difficult to describe the adsorption and reaction process of coal-oxygen complex, and it is difficult to guarantee its accuracy. Using the chemical bond energy estimation method to test the oxidation exothermic intensity will inevitably produce certain errors; the direct test method of microcalorimeter is widely used in the domestic coal industry. It has not been applied yet, and this method has high requirements for instruments; while differential scanning calorimetry cannot accurately measure the heat of oxidation below 50 °C, and it is only tested for small samples of about 10 mg, which cannot reflect the oxidation of coal the actual situation

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