Simultaneous Saxs-Waxs Study on Carbonization of Coking Coal

Abstract

Coking coal is an important raw material for coke production. In this study, in an inert atmosphere, two Chinese coking coal samples were respectively heated gradually to 1200°C to release volatile and form char and coke in succession, then cooled naturally to close room temperature to age the coke. The whole heating and cooling process on carbonization were monitored in situ by simultaneous small and wide-angle X-ray scattering (SAXS-WAXS) technique based on a synchrotron radiation platform. The simultaneous structural changes of pore and skeleton in coal during carbonization are revealed for the first time. The two raw coal samples, with similar carbon content and slightly different coalification degree, undergone a carbonization process similar in whole and different in parts. The carbonization presents approximately three stages during heating process and one stage during cooling process. The coal structure changes wavily with the increase of temperature and monotonously with the decrease of temperature. The pore and skeleton structure directly determine the reactivity and strength of coke. The corresponding structural change mechanism is analyzed.

Keywords: coking coal, high-temperature carbonization, synchrotron radiation, SAXS and WAXS