Assessment of the susceptibility of coals to spontaneous heating using wet oxidation potential difference technique

Abstract

Tthis study is proposed to assess the susceptibility of coals from different Indian coal mines and correlationstudy to fi nd ou the suitability of the methods for assessment of spontaneo us heating of coals. The wet oxidation potential difference experimentsT(WOPD) were conducted for 20 different coal samples collected fromdifferent India coal mines. the coal samples were collected by channel sampling and prepared according to the Indian Standards. the energy content of all the coal samples in terms of calorific values was measured with the Bomb Calorimeter and proximate analysis was also conducted so as to obtain volatile matter, fixed carbon, moisture content and calorific value. Correlation study was carried out to find the suitability of the methodto assess the spontaneous heating sus ceptibility of coal. Generally, Crossing Poin Temperature (CPT) method is used for assessment of spontaneous heating susceptibilit y of coal. However, this method has certain drawbacks. The results are dependent uponTpacking density, rate of heating and oxyge n flow rate etc., and sometimes results are not reproducible. Moreover, it takes long hours (more than three hours) to complete theexperiment. In comparison to CPT, WOPD experiments only takes about 40 minutes for completion and the results are reproducible as well. From the correlation analysis, it was found that WOPD indicated a very fair accuracy for the measure of spontaneous heating susceptibilityas it showed high correlation with the intrinsic propertiessuchas moisture and volatile matter.