TRANSPORT OF PENETRANTS IN THE MACROMOLECULAR STRUCTURE OF COALS II. EFFECT OF POROUS STRUCTURE ON PYRIDINE TRANSPORT MECHANISMS

Abstract
Pyridine transport in 600-850μm coal particles occurs by a non-Fickian mechanism which shows coupling of both diffusion and relaxation phenomena. In lignites (with carbon content less than 75%) the phenomenological pyridine transport mechanism is predominantly Fickian, whereas in bituminous coals (above 75% carbon) it approaches Case-II transport. However, when the porous structure of the coals is taken in consideration the true pyridine transport mechanism is Case-II transport.