7.Influence of air humidity on spontaneous combustion behavior of coal gangue

Abstract:

To investigate the variation laws of spontaneous combustion characteristics of coal gangue under different air humidities, firstly, programmed temperature rise experiments showed that at 380 ℃,the oxygen volume fractions of samples with 40%,52%,60%,68% and 80% air humidity were 18.06%,17.64%,17.27%,17.42% and 17.75%,respectively.The maximum oxygen consumption occurred at 60% humidity, where the volume fractions of CO,CH4,C2H3,and C2H6also reached their peaks.Therefore, at a certain temperature, increasing air humidity promotes oxygen consumption and related gas generation in coal gangue when humidity is below 60%,but inhibits them when humidity exceeds 60%.Additionally, the critical temperature for spontaneous combustion of coal gangue was determined to be 200 ℃,and the drying crack temperature was 300 ℃.Secondly, by calculating Graham's fire coefficient(R2), the air humidities were ranked in descending order of spontaneous combustion risk for coal gangue: 60%(R2=0.060),68%(R2=0.056),80%(R2=0.047),52%(R2=0.041),and 40%(R2=0.038).Thus, coal gangue exhibits the highest spontaneous combustion risk at 60% air humidity.

Keywords: gangue spontaneous combustion;program warming;air humidity;grignard fire coefficient