ESTIMATION OF LINEAR CONTRACTION OF ISOTROPIC FORMED GREEN CARBON DURING THE CARBONIZATION PROCESS

A method is developed to estimate the temperature dependency of a linear contraction of isotropic formed green carbon during the carbonization process. The linear contraction is given as functions of residue and true density, both of which are estimated from yields of gases released from filler and binder by devolatilization. The relation between true density and hydrogen content for the filler and binder is found to be same as that for coal and pre-heated coal. The relation is utilized to estimate the true density. Yields of released gases are measured at a constant heating rate of 1K/min to determine kinetic parameters, which are presented by the Arrhenius expression. Releases of H-2, CO2, CO2, CH4 and tar are considered. Linear contraction is estimated by using the kinetic parameters. The linear contractions which are estimated in the temperature range in which the porosity is kept constant agree well with the measured values for heating rates of 1 and 3K/min. The estimated values for another formed green carbon which has a different mixing ratio of filler and binder also agree with the measured ones in the same temperature range.