410
5 Kinetic Analysis
The kinetics of various carbonaceous solid fuels such as biomass, coal, and their
char have been extensively studied [20–23]. However, the study of kinetics related
to the gasification of petcoke has been limited due to the fact that many reaction
models related to the gasification of biomass or coal are not universally acceptable
in the case of petcoke gasification [14]. However, in the present section we have
tried to cover few studies related to the gasification of the petcoke under various
operating conditions.
Zhang et al. [14] studied the kinetics and reactivity of the petcoke steam gasification in a micro-fluidized bed. They used the homogenous model and the shrinking
core model for predicting the kinetic parameters related to the petcoke gasification.
The shrinking core model showed better results in establishing correlations with the
experimental data as compared to the homogeneous model. The activation energy of
a 10 wt% blending of black liquor with petcoke had a much lesser value of 77 kJ/
mol as compared to that of only petcoke gasification (120 kJ/mol). The activation
energy got further decreased to 63 kJ/mol on introducing 5% oxygen with steam
suggesting that synergistic effect was present between the black liquor and oxygen.
Zou et al. [9] carried out the kinetic modeling of petcoke gasification where CO 2
was used at 0.1 MPa and 1248–1323 K. The activation energy of petcoke CO 2 gasification was 198 kJ/mol with the order of reaction falling between 0.54 and 0.88
within the operated temperature range.
The study of kinetics of co-gasification of petcoke containing high sulfur and
biomass (rice husk) were carried by Gajera et al. [24]. They carried out thermogravimetric analysis at three different heating rates (10, 20, and 30 °C/min) and
used the TGA data in isoconversional methods such as Flynn-Wall-Ozawa (FWO)
and Kissinger-Akahira-Sunose (KAS) for estimating the kinetic parameters. The
activation energy for petcoke gasification were 128.3, and 126.75 kJ/mol, for FWO
and KAS method, respectively, while it decreased to 87.84, and 86.85 kJ/mol,
respectively, for the 1:3 ratio blending of petcoke to biomass. They also stated that
during the co-gasification process the reactivity of petcoke increased significantly
with presence of rice husk. Wang et al. [25] did the kinetic study of co-gasification
for the petcoke and biomass char. They used the TGA data in the three different nth
order gas-solid models (unreaction core model (URCM), volume reaction model
(VRM), and random pore model (RPM)) to intercept the data of carbon conversion.
The activation energy of bio-char (corncob) and petcoke were 243.3 and
203.2 kJ/mol, respectively, while for the co-gasification of petcoke/bio-char ratio of
4:1 was 197.8 kJ/mol.
Edreis et al. [26] studied the kinetic and the synergistic behavior the water cogasification of petcoke with biomass. There was a significant interaction prevailing
between blending ration and H 2 O concentration when the value was less than 50%.
They also observed only single char gasification stage above 700 °C and at 75%
H 2 O. The boundary reaction model used for kinetic parameter estimation of
J. P. Chakraborty and R. K. Singh
5 Kinetic Analysis
The kinetics of various carbonaceous solid fuels such as biomass, coal, and their
char have been extensively studied [20–23]. However, the study of kinetics related
to the gasification of petcoke has been limited due to the fact that many reaction
models related to the gasification of biomass or coal are not universally acceptable
in the case of petcoke gasification [14]. However, in the present section we have
tried to cover few studies related to the gasification of the petcoke under various
operating conditions.
Zhang et al. [14] studied the kinetics and reactivity of the petcoke steam gasification in a micro-fluidized bed. They used the homogenous model and the shrinking
core model for predicting the kinetic parameters related to the petcoke gasification.
The shrinking core model showed better results in establishing correlations with the
experimental data as compared to the homogeneous model. The activation energy of
a 10 wt% blending of black liquor with petcoke had a much lesser value of 77 kJ/
mol as compared to that of only petcoke gasification (120 kJ/mol). The activation
energy got further decreased to 63 kJ/mol on introducing 5% oxygen with steam
suggesting that synergistic effect was present between the black liquor and oxygen.
Zou et al. [9] carried out the kinetic modeling of petcoke gasification where CO 2
was used at 0.1 MPa and 1248–1323 K. The activation energy of petcoke CO 2 gasification was 198 kJ/mol with the order of reaction falling between 0.54 and 0.88
within the operated temperature range.
The study of kinetics of co-gasification of petcoke containing high sulfur and
biomass (rice husk) were carried by Gajera et al. [24]. They carried out thermogravimetric analysis at three different heating rates (10, 20, and 30 °C/min) and
used the TGA data in isoconversional methods such as Flynn-Wall-Ozawa (FWO)
and Kissinger-Akahira-Sunose (KAS) for estimating the kinetic parameters. The
activation energy for petcoke gasification were 128.3, and 126.75 kJ/mol, for FWO
and KAS method, respectively, while it decreased to 87.84, and 86.85 kJ/mol,
respectively, for the 1:3 ratio blending of petcoke to biomass. They also stated that
during the co-gasification process the reactivity of petcoke increased significantly
with presence of rice husk. Wang et al. [25] did the kinetic study of co-gasification
for the petcoke and biomass char. They used the TGA data in the three different nth
order gas-solid models (unreaction core model (URCM), volume reaction model
(VRM), and random pore model (RPM)) to intercept the data of carbon conversion.
The activation energy of bio-char (corncob) and petcoke were 243.3 and
203.2 kJ/mol, respectively, while for the co-gasification of petcoke/bio-char ratio of
4:1 was 197.8 kJ/mol.
Edreis et al. [26] studied the kinetic and the synergistic behavior the water cogasification of petcoke with biomass. There was a significant interaction prevailing
between blending ration and H 2 O concentration when the value was less than 50%.
They also observed only single char gasification stage above 700 °C and at 75%
H 2 O. The boundary reaction model used for kinetic parameter estimation of
J. P. Chakraborty and R. K. Singh