An
accurate and quantitative description of the pore structure
of gasification-coke using fractal geometry could be of great significance
to its industrial utilization. In this study, gasification-coke was
prepared with low-quality coal blending at different high-temperature
residence times to investigate the variation in the pore structure,
fractal dimensions, reactivities, and their relationship. The pore
structure parameters (e.g., specific surface area, pore volume, and
average pore diameter) of gasification-coke were investigated by low-temperature
N
2
adsorption/desorption and mercury intrusion porosimetry.
Fractal dimensions
D
1
and
D
2
(at relative pressures of 0–0.5 and 0.5–1,
respectively) were calculated using the fractal Frenkel–Halsey–Hill
model, and the fractal dimension
D
3
was
obtained using the Menger sponge model. The results show that the
pore structure systems of gasification-coke prepared at different
high-temperature residence times are continuous and complete, which
contributes to the gasification reaction. The variation trend of the
macropore structure parameters is more complex than that of micropore
and mesopore with the extension of the high-temperature residence
time. It is found that
D
1
is linearly
correlated with the micropore specific surface area, indicating that
D
1
is more suitable for reflecting the roughness
of the micropore surface;
D
2
is linearly
correlated with the mesopore volume and can describe the volumetric
roughness of the mesopore; and
D
3
reflects
the irregularities and surface roughness of the macropores. Gasification
reactivity is closely related to the
D
2
value, and the reactivity of the gasification-coke may be improved
if the number of mesopores is increased by controlling the high-temperature
residence time or other pyrolysis conditions. The research results
will provide theoretical reference for controlling the gasification
reaction of gasification-coke and gasifier design.