Abstract
Pyrolysis of five coals at high temperatures of ≧1000℃ has been studied with a fixed bed quartz or free fall graphite reactor to examine carbon structures in chars after devolatilization. The proportion of crystallized carbon with turbostratic structures increases irrespective of kind of coal, when pyrolysis temperature or solid residence time is raised from 1000 to1 350℃ or from 0 to 120sec, respectively. Highly dispersed CaO with the size of 20-50nm promotes transformation reactions of amorphous carbon to crystallized carbon. The reaction mechanism is discussed in term of interactions between CaO particles and char substrate.
