Study on relationship between mechanical parameters and thermalconductivity of pre-oxidized coal

In order to study a different pre-oxidization temperature affected to coal basic mechanics parameter and thermal conductivity characteristic parameters as well as the linear correlation between the two parameters, a long-flame coal from Liuhuanggou, Xinjiang was selected, a programmed temperature rising box was applied to the pre-oxidization treatment of the coal samples with the temperatures of 30, 80, 140 and 200 ℃. Then a MTS880 electro-hydraulic servo testing machine, LFA457 laser thermal conductivity analyzer and FF35 CT industrial computed tomography system were applied to study the coal mechanics parameter, thermal conductivity coefficient and crack variation condition within the internal boreholes. The correlation coefficient was introduced to quantitatively calculate the linear correlation between the elastic modulus and the thermal conductivity coefficient. The results showed that under the pre-oxidation function with a temperature of 140 ℃, the elastic modulus, compressive strength and thermal conductivity coefficient would be the largest in all. Under the pre-oxidation function with a temperature of 200 ℃, the micropore cracks of the coal samples would relatively be the maximum and the elastic modulus and compressive strength would be the minimum. When the pre-oxidization temperature was at 30～200 ℃, the correlation coefficient between the elastic modulus and thermal conductivity coefficient would be greater or equal to 0.992, would be positively correlated with the height and all would be firstly increased and then would be reduced in tendency with the pre-oxidization temperature increased.