R. Leboda et al., EFFECT OF CALCIUM CATALYST LOADING PROCEDURE ON THE POROUS STRUCTURE OF ACTIVE-CARBON FROM PLUM STONES MODIFIED IN THE STEAM GASIFICATION PROCESS, Carbon (New York), 36(4), 1998, pp. 417-425
The effect of mode of calcium catalyst deposition on the active carbon
(produced from plum stones) surface on the formation of micro- and me
soporous structures during gasification of the carbon with steam as we
ll as on the kinetics of this process was investigated. The catalyst (
1.44%) was deposited by conventional impregnation or ion exchange. Par
tial gasification of the modified carbon in the absence of catalyst ca
uses significant increase of micropore volume and small increase of me
sopore surface area with the increase of burn-off degree. On the contr
ary, gasification of the samples in the presence of calcium catalyst c
auses the decrease of sorption capacity of micropores and the signific
ant increase of mesopore surface. The above changes are more effective
for the samples containing the catalyst deposited by ion-exchange. Mi
cropore capacity and surface area of mesopores were determined by mean
s of the alpha(S)-method. The adsorption process on the heterogeneous
solids was described by means of integral equation including various l
ocal isotherms. This equation has been solved by the regularization me
thod. On the basis of this method changes in the structural parameters
were estimated. The activation energies of individual reactions were
determined. The mechanism of gasification process as well as the selec
tion of proper concentration of steam optimum from the kinetic viewpoi
nt have been discussed. (C) 1998 Elsevier Science Ltd. All rights rese
rved.