In order to obtain fundamental informations on hydrogasification of coal, thermogravimetric curves were measured for chars prepared by heat-treatment of coals at temperature range from 400°C to 900°C.
Kinetic analysis of hydrogasification was done with the following equation in which the rate was expressed in terms of unit surface area;
Rate constant= (-dw/dt) /S= (-dw/dt) /Cmiddot;w2/3=1/Ck
where w and S are weight and sruface area of samples, respectively.C is a constant depending on both shape factors and density.
It was found from the results that k value was generally larger for chars than those for original coals and a maximum value of k was obtained for the char heat-treated at 600°C.
As the rate was closely related to the internal surface area of each sample, the reaction would be thought to proceed in such a way that gaseous H2 molecule could enter even into a considerably small pore of the solid to react with carbon.