Archive | 2019
Variations of Micropore Structure of Coal with Adsorption/Desorption of Gas
Abstract
Summary In this work, we conducted high pressure CH4 adsorption and 3D reconstruction of coal microstructure to visualize and evaluate the pore characterisitcs. This methodology finds its uniqueness in effective quantization especially for the nano and intricate pore structures. Observations reveal that pore count and specific surface area increases and it is more dominant for the pores in the range of mesopores (2–50 nm). This phenomenon is mostly attributed to the coal swelling effect, which could fracture the unswelling mineral by swelling stress. Thus, the mineral phase (especially calcite) should be somehow damaged during the adsorption into the coal matrix and thus became weak. Mineral phase boundaries in the coal matrix had significantly compressed damaged fractures system by the coal matrix swelling. In summary, the tested coal sample could drastically weaken due to adsorption by swelling stress fracturing.