The pore structure of carbonaceous materials was studied using image analysis. The effect of
annealing on the porosity and pore geometry of cokes, chars, and pyrolyzed coals (laboratory
chars) was examined in the temperature range of 973 K to 1773 K (700 C to 1500 C). The
porosity of chars and pyrolyzed coals significantly increased during annealing at temperatures
below 1373 K (1100 C) due to volatile matter release. Further increasing of the annealing
temperature from 1373 K to 1773 K (1100 C to 1500 C) caused marginal porosity evolution.
The porosity of cokes was not affected by annealing at temperatures below 1573 K (1300 C)
and slightly increased in the temperature range 1573 to 1773 K (1300 C to 1500 C). The
increase in the porosity of chars and pyrolyzed coals during annealing at temperatures 1373 K
to 1773 K (1100 C to 1500 C), and cokes at 1573 K to 1773 K (1300 C to 1500 C), was a
result of reactions with oxides of their mineral phases. Annealing had a marginal effect on the
pore shape (Feret ratio) of carbonaceous materials, but enlarged the pore size of chars and
pyrolyzed coals and decreased their pore density.