Thermochemical studies of wetting phenomena of coals by organic solvents such as methanol or tetralin

Abstract

The wetting of coal by tetralin and methanol was studied at temperatures of 303 K and 323 K. Calorimetric measurements indicated that there was no correlation of enthalpy of wetting by methanol and the coal specific area. For high volatile bituminous coal and subbituminous coals the most energetic step of wetting by methanol was the swelling process. The enthalpy of methanol-induced swelling was approximately 1 J g −1% −1 at 303 K. The heats of wetting by tetralin were negative for all the coals studied. The enthalpies of wetting high rank coals such as anthracite and low volatile bituminous coal are very sensitive to temperature increasing by a factor of 4 for an increase of temperature from 303 K to 323 K. The enthalpy of wetting by tetralin is highly dependent on the number of polar groups present on the coal surface.