Effect of heating rate on microstructure evolution and mechanical-seepage characteristics of hot-pressed briquettes

Briquette production method is vital to improving its strength and permeability in physical simulation test of coal mine gas disasters. This study adopts the Horsfield dense packing theory to optimize the ratio of briquette materials and investigates the mechanical-seepage characteristics, molecular and pore structure of hot-pressed briquettes under different heating rates. Results show that as the heating rate increases, the proportion of C1s elements and the contents of alcohol, C—O/C—OH, aromatic hydrocarbons and C—C/C—H in functional groups in the molecular structure of hot-pressed briquettes show a fluctuating pattern of initial increase, subsequent decrease and final increase; the uniaxial compressive strength first increases and then decreases, while the initial permeability first decreases and then increases. The optimum heating rate is 5 ℃/min. This study offers references to improving the similarity between briquette and raw coal.