404
validated using experimental data obtained for a slagging gasifier. The effect of feed
oxygen/coke and steam/coke ratios feed coke rates on gasification performance was
carried out. High petcoke conversion was achieved and peak gas temperature
exceeded 1500 °C. Besides, moving bed gasifier operation in slagging zone with
high petcoke flux of over 4000 kg/m
2
/h was obtained. The moving bed gasifier
(MBG) exhibited better performance than an entrained flow gasifier (EFG) while
considering energy efficiency and oxygen consumption. Two different empirical
molecular formulae were deduced for fixed carbon and volatile carbon, e.g.,
CH x S zs N zn and CH y O zo , respectively; and it worked satisfactorily for the simulation
of petcoke gasification. Trommer et al. [7] used concentrated solar power for the
production of hydrogen by steam-gasification of petcoke. The benefits with this
process are as follows: (1) enhancement of calorific value of feedstock, (2) gaseous
products are not contaminated, and (3) discharge of pollutant to the environment is
avoided. Two feedstocks were used, e.g., flexicoke and delayed coke. The net process was endothermic by approximately 50% of the lower calorific value of feedstock. An equimolar mixture of H 2 and CO was produced at equilibrium, at above
1300 K. According to a second law analysis, this syngas may be converted to H 2
using water-gas shift reaction followed by H 2 /CO 2 separation and then the produced
H 2 may be utilized in a fuel cell for power generation, thus doubling the specific
electrical output and halving CO 2 emission. Li et al. [8] studied non-isothermal
thermogravimetric analysis (TGA) of petcoke gasification. The catalytic effects of
FeCl 3 , CaCl 2 , KCl, K 2 CO 3 , K 2 SO 4 , KAC, and KNO 3 were studied. It was observed
that noncatalytic gasification was inefficient below 1000 °C. The rate of gasification, however, increased rapidly upon the addition of catalyst. K 2 CO 3 appeared to be
a very efficient catalyst as with this catalyst, the gasification reaction was complete
within 10 min and at a temperature of 900 °C. The catalytic mechanism was studied
in detail by performing Raman spectroscopy and X-ray diffraction (XRD) studies of
char samples collected at different conversion levels. XRD analysis suggested that
the degree of graphitization decreased with K 2 CO 3 addition which was favorable for
char gasification. Zou et al. [9] studied gasification of petcoke in the presence of
CO 2 using a pressurized TGA, at a temperature range of 1248–1323 K. It was
observed that the rate of gasification increased with increasing conversion up to
x = 0.3, then it decreased. A normal distribution function model was proposed to fit
the kinetic data. The rate of reaction followed Arrhenius law. The activation energy
obtained during petcoke gasification in the presence of CO 2 was 198 kJ mol
−1
, and
the reaction order was 0.54–0.88. These results were comparable with previously
published data. Zou et al. [10] studied the effect of mechanochemical treatment during CO 2 gasification of petroleum coke. A mechanochemical treatment during
grinding of petcoke was applied. An additive was derived by drying black liquor
obtained from paper industry and it was used in the grinding process. Results
showed that grinding improved gasification and wet grinding had more pronounced
effect than dry grinding. When wet grinding of petcoke and additive took place
together, the active metals in additive were retained in the solid phase, thereby causing a high catalytic reactivity to the coke-CO 2 reaction. It has been observed that
long time mechanical grinding is usually responsible for crystalline-amorphous
J. P. Chakraborty and R. K. Singh
validated using experimental data obtained for a slagging gasifier. The effect of feed
oxygen/coke and steam/coke ratios feed coke rates on gasification performance was
carried out. High petcoke conversion was achieved and peak gas temperature
exceeded 1500 °C. Besides, moving bed gasifier operation in slagging zone with
high petcoke flux of over 4000 kg/m
2
/h was obtained. The moving bed gasifier
(MBG) exhibited better performance than an entrained flow gasifier (EFG) while
considering energy efficiency and oxygen consumption. Two different empirical
molecular formulae were deduced for fixed carbon and volatile carbon, e.g.,
CH x S zs N zn and CH y O zo , respectively; and it worked satisfactorily for the simulation
of petcoke gasification. Trommer et al. [7] used concentrated solar power for the
production of hydrogen by steam-gasification of petcoke. The benefits with this
process are as follows: (1) enhancement of calorific value of feedstock, (2) gaseous
products are not contaminated, and (3) discharge of pollutant to the environment is
avoided. Two feedstocks were used, e.g., flexicoke and delayed coke. The net process was endothermic by approximately 50% of the lower calorific value of feedstock. An equimolar mixture of H 2 and CO was produced at equilibrium, at above
1300 K. According to a second law analysis, this syngas may be converted to H 2
using water-gas shift reaction followed by H 2 /CO 2 separation and then the produced
H 2 may be utilized in a fuel cell for power generation, thus doubling the specific
electrical output and halving CO 2 emission. Li et al. [8] studied non-isothermal
thermogravimetric analysis (TGA) of petcoke gasification. The catalytic effects of
FeCl 3 , CaCl 2 , KCl, K 2 CO 3 , K 2 SO 4 , KAC, and KNO 3 were studied. It was observed
that noncatalytic gasification was inefficient below 1000 °C. The rate of gasification, however, increased rapidly upon the addition of catalyst. K 2 CO 3 appeared to be
a very efficient catalyst as with this catalyst, the gasification reaction was complete
within 10 min and at a temperature of 900 °C. The catalytic mechanism was studied
in detail by performing Raman spectroscopy and X-ray diffraction (XRD) studies of
char samples collected at different conversion levels. XRD analysis suggested that
the degree of graphitization decreased with K 2 CO 3 addition which was favorable for
char gasification. Zou et al. [9] studied gasification of petcoke in the presence of
CO 2 using a pressurized TGA, at a temperature range of 1248–1323 K. It was
observed that the rate of gasification increased with increasing conversion up to
x = 0.3, then it decreased. A normal distribution function model was proposed to fit
the kinetic data. The rate of reaction followed Arrhenius law. The activation energy
obtained during petcoke gasification in the presence of CO 2 was 198 kJ mol
−1
, and
the reaction order was 0.54–0.88. These results were comparable with previously
published data. Zou et al. [10] studied the effect of mechanochemical treatment during CO 2 gasification of petroleum coke. A mechanochemical treatment during
grinding of petcoke was applied. An additive was derived by drying black liquor
obtained from paper industry and it was used in the grinding process. Results
showed that grinding improved gasification and wet grinding had more pronounced
effect than dry grinding. When wet grinding of petcoke and additive took place
together, the active metals in additive were retained in the solid phase, thereby causing a high catalytic reactivity to the coke-CO 2 reaction. It has been observed that
long time mechanical grinding is usually responsible for crystalline-amorphous
J. P. Chakraborty and R. K. Singh