Gas emission characteristics of tectonic coal and microscopic explanation of pore structure

The gas emission experiments of coal particles at a constant temperature were conducted to study the differ- ence of gas emission between tectonic coal and original coal. Results show that the amount of gas emission of tectonic coal in the first one minute is 2. 15 -4. 06 times of original coal. The time required to reach the full amount of gas emission by tectonic coal is 25% less than that of original coal,and the full emission amount of original coal is slightly higher than that of tectonic coal. The mathematical expressions which can represent the gas emission of tectonic coal and original coal are different. To explain the experiment results,the pore structures of coal were tested by the mercury intrusion and the low temperature nitrogen adsorption methods. Analysis shows that the distribution of mesopore and macropore is the main factor inducing the difference of the gas emission characteristics between tectonic coal and origi- nal coal. Other influencing factors need to be investigated such as macromolecular structure.