According to the International Union of Pure and Applied
Chemistry (IUPAC) classification, the size ranges of micro-, meso-,
and macropores are defined as less than 2, 2e50, and over 50 nm,
respectively. Table 5 and Fig. 2 show that the original activated
carbon consisted mainly of micro- and mesopores, and considerable
numbers of both micro- and mesopores of the activated carbon
disappeared after gasification. The tar adsorbed on the activated
carbon or the coke formed by reactions among tar molecules
seemed to block mainly mesopores of the original activated carbon,
which provide passages for adsorbates to reach micropores. However,
in a previous work, it was demonstrated that a severe deactivation
of activated carbon did not occur because regeneration
reactions for activated carbon, such as the reactions between gas
flowing from the fluidized bed reactor and tar (or coke) on the
activated carbon, took place continuously [25]. Fig. 3 presents
variations of gas compositions according to the gasification time for
Run 6