THE UNSTEADY ST A TE DIFFUSION OF GASES FROM ANTHRACITE AT HIGH TEMPERATURES

Special Research Report SR-24 The micropore structure of a Pennsylvania anthracite has been investigated by subjecting 200x325 mesh and 65xl00 mesh samples of the material to uniform internal pressures in excess of atmospheric pressure and then observing the' subsequent unsteady state release of the charged gas. Although previous investigators have carried out sorption measurements on coals under diffusion controlling conditions, no attempts appear to have been made to measure diffusion only - that is, to measure diffusion rates under thermal conditions unfavorable to gas adsorption. In addition to the practical consideration that diffusion data do not exist above approximately l00°c., it was decided that a high temperature study would substantially eliminate the interfering effect of large concentrations of adsorbed gas upon the mobility of the diffusing molecules.