Study on characteristics of initial desorption of tectonic coal and primary structural coal in northern Guizhou

This paper is devoted to reveal the initial desorption characteristics of tectonic coal and primary structural coal in Guizhou.The adsorption and desorption experiments of tectonic coal and primary structural coal of Xinglong Mine in northern Guizhou have been carried out under different temperatures and pressures. The relationship between accumulated gas desorption capacity and time is illustrated. The influence of temperature and pressure on initial desorption of tectonic coal and primary structural coal is then analyzed. The results show that the cumulative desorption capacity of tectonic coal and primary structural coal increases with time. In the same period, greater total gas desorption capacity is associated with higher temperature. Greater desorption capacity and desorption rate within 60 seconds before desorption are associated with higher temperature as well. Similarly, the desorption rate increases as the pressure increases and the increasing rate decreases with time. The results also show that the desorption capacity is proportion to the desorption pressure. The tectonic coal is greater than the primary structural coal in initial desorption velocity,desorption capacity within the first 60 seconds, and decrease of desorption rate after 60 seconds. However, the primary structural coal is larger than the tectonic coal in desorption capacity between 60 and 1 800 seconds. Desorption rate and total desorption capacity of the primary structural coal are higher than desorption rate and total desorption capacity of the tectonic coal between 1 800 and 7 200 seconds while decrease of desorption rate of the primary structural coal is slower than that of the tectonic coal. Moreover, the desorption capacity difference between the primary structured coal and the tectonic coal increases with the increases of desorption temperature and gas pressure.