Coal rank and coke reactivity

For a series of cokes prepared under identical carbonizing conditions it was shown that rates of reaction with carbon dioxide/nitrogen mixtures at about 1000°C were generally higher for the cokes prepared from coals of above 30% volatile matter. The reaction rates of cokes prepared from certain Durham coals were generally higher than anticipated. Gasification of cokes prepared from certain Durham coals were generally higher than anticipated. Gasification of the cokes resulted in loss of strength, decrease in apparent density, enlargement of pores and reduction of pore-wall thickness. It appeared that burn-off was primarily associated mineral constituents of the coke ash upon gasification rates was detected. A tentative relation was derived between gasification rates and the ratio of pore-wall thickness to pore diameter of the cokes. In turn, this latter ratio appeared to bear some relation to the oxygen content of the coal. The majority of the parameters studied were measured by established techniques. Porosity was determined by mercury pressure porosimetry and the Quantimet 720 automatic image analysis microscope was employed for structural studies. The accuracy of the measurement of pore and pore-wall dimensions was approximately ± 2%.