Study on fine coal porosity features and response to seam freezing

In order to verify the freezing affected to the structure coal pore existed or not,based on a high fragility and deformed rushed fine coal as an example,the m ercury intrusion porosimetry and the low temperature liquid nitrogen method were applied to test and measure the original sample,7 days freezing sample and 30 days free zing sample and to study the differences between the pore volume specific surface area of the pore and pore diameter structure before and after the samples frozen. The r esults showed that after the sample frozen,the pore volume( mercury intrusion porosimetry) of the sample increased. With the pore diameter increased,the difference would be varied. The variation amplitude of the sample with 30 days frozen was lower than the sample with 7 days frozen. After the sample frozen,the interconnection pore and vi al pore were increased. As the pore with diameter of 100 nm( liquid nitrogen),after the sample frozen,the pore volume and specific surface area would be decreased with th e freezing time increased and the pore diameter of the sample would be increased. The frozen could cause damages to the pore volume,pore specific surface area and por e diameter structure of the samples and would make the small pores transfer to a larger pore. Within different pore diameter range and different freezing time ,the damage d, egree caused would not be the same. The pore diameter distribution of the samples and the coordinated variation of the original sample showed that the freezing would not make a fundamental variation occurred in the pore diameter distribution.