Chemical disintegration of coal in triaxial stress fields

Abstract This paper studies the effects of stress and flow rate on comminution rates of a coal sample. Chemical disintegration of coal involves introducing a solvent or comminution reagent into a coal seam and converting the monolithic coal into a particulate slurry of coal particles. A 2.5 molar solution of methanol and sodium hydroxide solution at 55 °C was used as the chemical reagent and its comminution ability was studied under different applied stress and solvent flow rates. The comminution rates ranged from 19.5 to 1.2 mg/(cm 2 ·h) as the overburden stress was increased from 0 to 17 MPa. The results showed a substantial increase in the comminution rate at stresses higher than 10 MPa and the disintegrated particles demonstrated a high degree of angularity, indicative of physical breakage. It was also shown that the fracturing rates increased with a rise in the solvent flow rate.