EFFECT OF RANK AND PETROGRAPHIC COMPOSITION ON THE SWELLING BEHAVIOR OF COALS

The relationship between petrographic composition and swelling ratio i n the 200-300 degrees C range for five subbituminous to high-volatile bituminous coals has been investigated The amount of fluorescing humin ite / vitrinite plus the total liptinite macerals (i.e., ''reactive'' macerals) of the coal is the determining factor of coal swelling behav ior There is an increase in swelling ratio with increasing coal rank a s expressed by mean huminite / vitrinite reflectance. For coals of the same or very similar rank the swelling characteristics were directly related to the amount of fluorescing huminite / vitrinite in the coal. It is also observed that the fluorescence of vitrinite in the three h igher rank coals showing better swelling ratios is related to the pres ence of fluorophases and labile hydrogen in the vitrinite matrix The t wo lower rank coals that exhibit poor swelling characteristics lack an y visible fluorescence in the huminite matrix.