Sorption of methane in moist coal

Abstract

The dependence on moisture content of the methane sorption capacity of four American coals has been investigated. Bituminous coals from Virginia, West Virginia, Oklahoma and Pennsylvania were studied at a temperature of 30 °C, and at pressures up to 60 atm. Methane capacity decreased with increasing moisture content up to a certain value of moisture content that was characteristic for each coal. Moisture present in excess of the critical value had no further effect on methane sorption. The critical values of moisture content, m c (wt %), were related to coal oxygen content, x o (wt %), by the expression m c = ( X O + 1.51 )/(3.98 − 0.229 X O ).