Influence of added potassium and sodium carbonates on CO_2 reactivity of the char from a demineralized inertinite rich bituminous coal

摘要

The addition of K_2CO_3, Na_2CO_3 and a mixture of the two catalysts showed an increase in the CO_2 reactivity of the char prepared from the demineralized inertinite rich bitumious coal at 900℃ in nitrogen. The CO_2 reactivity of the char is higher when the catalysts are added to the coal before preparing the char in comparison to addition of the catalyst to the prepared char. The distribution of the catalyst on the char particles thus seems to be better upon addition of the catalyst to the coal (before charring). An added effect could be the evolution of CO_2 during charring that may increase the surface area of the produced char. The surface area values of the chars (＞400m~2/g) were higher than the values for the demineralized coal samples (approximately 150m~2/g) and the values for the char prepared from the coal with added catalysts increased from 413 to 445 m~2/g. XRF, XRD and QEMSCAN analyses were performed to determine the species of K_2CO_3 and Na_2CO_3 formed during thermal treatment of the samples. KG, NaCl, K_2O and Na_2O are some of the species that were detected.