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Transformation behaviors of excluded pyrite during O2CO2 combustion of pulverized coal.

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ASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING
Asia-Pac. J. Chem. Eng. 2010; 5: 304–309
Published online 14 May 2009 in Wiley InterScience
(www.interscience.wiley.com) DOI:10.1002/apj.277
Special Theme Research Article
Transformation behaviors of excluded pyrite during O2/CO2
combustion of pulverized coal
Changdong Sheng,1 * Jun Lin,2 Yi Li,1 and Chao Wang1
1
2
School of Energy and Environment, Southeast University, Nanjing 210096, P. R. China
Shanghai Institute of Applied Physics, Chinese Academy of Science, Shanghai 201800, P. R. China
Received 21 August 2008; Revised 18 January 2009; Accepted 19 January 2009
ABSTRACT: The article was addressed to the transformation of excluded pyrite during O2 /CO2 combustion of
pulverized coal. Raw pyrite mineral was added to a pulverized coal sample, which was density fractionated to remove the
excluded minerals, to simulate the excluded pyrite present in coal. The mixed sample was burned in a drop tube furnace
in O2 /CO2 and O2 /N2 conditions to generate the residue ash, which was characterized by Mössbauer spectroscopic and
size analyses. It was found that, in comparison with O2 /N2 combustion at the same oxygen concentration, slightly less
iron glass silicate was formed from excluded pyrite and silicates although the transformation of pyrite to oxides was
slowed in O2 /CO2 combustion, different from the behaviors of included pyrite in pulverized coal those were observed in
previous study. Additionally, less fragmentation of excluded pyrite particles was also observed in O2 /CO2 combustion.
 2009 Curtin University of Technology and John Wiley & Sons, Ltd.
KEYWORDS: pulverized coal; O2 /CO2 combustion; excluded pyrite; transformation
INTRODUCTION
Oxy–fuel combustion of pulverized coal produces a
CO2 -concentrated flue gas stream, enabling an easy
CO2 recovery. It is also potential to achieve near-zero
emission.[1] Therefore, oxy–fuel combustion has been
recognized to be a promising technology for conventional pulverized coal–fired power plants to mitigate
CO2 emission.[1,2] Because oxygen/recycled flue gas is
commonly used to replace air for combustion, there are
significant changes in the combustion medium and in
the composition of in-furnace gases in comparison with
traditional air combustion. Such changes have impacts
on the combustion processes of coal particles including
devolatilization and ignition,[3] flame propagation,[4,5]
char combustion[6] and combustion characteristics.[7,8]
While transformations of coal minerals are intimately
associated with coal particle combustion processes, the
changes from air combustion to oxy–fuel combustion
also have impacts on mineral transformations and ash
formation behaviors.[9,10]
Iron has been identified to be a dominant factor contributing to slagging on water wall of pulverized coal–fired furnace.[11,12] Iron-bearing minerals
*Correspondence to: Changdong Sheng, School of Energy and
Environment, Southeast University, Nanjing 210096, P. R. China.
E-mail: c.d.sheng@seu.edu.cn
 2009 Curtin University of Technology and John Wiley & Sons, Ltd.
identified in coal are mainly pyrite, siderite and ironcontaining silicates such as illite. Previous studies
regarding air combustion have revealed that transformation behaviors of iron-bearing minerals depend on
mineral types and their associations with coal particles (i.e. included or excluded), reaction temperature and gas atmosphere.[13 – 17] Our recent experimental
study indicated that, in comparison with air combustion,
O2 /CO2 combustion has changed iron distribution in
iron-containing phases formed in coal residue ash.[9,10]
However, because pulverized coal samples were used in
the study, various types and occurrences of the iron minerals were contained in the coal sample.[10] In particular,
pyrite might occur as included or excluded association with coal matrix of the pulverized coal particles.
As a result, the influence of gas atmosphere varying
from air combustion to O2 /CO2 combustion on their
transformations has not clarified yet. In the present
work, a raw pyrite mineral sample, which was rich in
pyrite, was added to a pulverized coal to simulate the
excluded pyrite in combustion experiment. The mixture
was burned in a drop tube furnace (DTF) to generate
ash samples which were subjected to composition analysis. The study was addressed to the transformation of
excluded pyrite under O2 /CO2 combustion condition
so as to probe the impacts of changing gas atmosphere
on ash formation behaviors of excluded pyrite and its
subsequent impact on slagging propensity.
Asia-Pacific Journal of Chemical Engineering
TRANSFORMATION BEHAVIORS OF EXCLUDED PYRITE DURING O2 /CO2
EXPERIMENTAL
The powder of a raw pyrite mineral was mixed into
a pulverized coal to form the sample for combustion
experiment. The pulverized coal was bituminous with
a size of 100–300 µm and a specific gravity less than
1.4. It was obtained by density fractionation with heavy
liquid to remove the excluded minerals from the parent coal. The proximate and ultimate analyses and the
ash composition of the pulverized coal are summarized
in Table 1. It can be seen that the ash content is very
low, indicating that most of the minerals, particularly
the excluded minerals, were removed and the remained
were mainly those included within the coal particles.
The raw pyrite powder had a size of less than 150 µm.
Its mineral and elemental compositions, determined by
the combination of X-ray diffraction (XRD) analysis
and X-ray fluorescence (XRF) spectrometry analysis,
are presented in Table 2. The mass fraction of the mineral powder mixed into the pulverized coal was 15%.
As a result, the fraction of iron originally occurring in
the pulverized coal was estimated to be less than 10%
of the total iron in the mixture and the iron species
in the sample could be considered mostly the excluded
pyrite. As shown in Table 2, the raw pyrite mineral was
rich in pyrite content, but it also contained other minerals. Nevertheless, the unique composition, especially the
association of pyrite with silicate minerals (i.e., quartz
and kaolinite), allowed the investigation on the excluded
pyrite interacting with silicates during the transformation to distinguish its behavior from that of the included
pyrite.
The mixed sample was burned in a DTF. The core
of the DTF was a 2-m-long alumina tube heated by
three independently controlled furnace sections. The
Table 1. Properties of the pulverized coal (specific
gravity <1.4).
Proximate analysis (wt%)
Ad
4.34
Ultimate analysis (wt%)
Vd
FCd
Cd
Hd
Nd
Od + Sd
27.33
68.33
81.33
5.41
1.14
7.50
Ash composition, wt%
SiO2
Al2 O3
Fe2 O3
CaO
MgO
K2 O
Na2 O
TiO2
53.00
35.47
5.73
2.54
0.83
0.54
0.50
1.39
description of the DTF was detailed elsewhere.[18] The
sample was fed into the tube at the top of the reactor
by a microfeeder at a feeding rate of ca. 0.4 g/min and
passed through the tube to finish the combustion and
reaction. The coal and the resulting ash particles passed
through the reactor tube with an average residence time
of about 1.0 s. Because the density of the pyrite mineral
particles was much higher than that of the coal particles,
their residence time was estimated as 0.5 s. At the
bottom of the reactor, the reaction products were drawn
out through a water-cooled high-purity N2 –quenched
sampling probe. After the probe, a glass fiber filter with
a pore size of 0.3 µm was used to collect the residue
ash which was then subjected to iron composition and
particles size analyses.
The O2 /CO2 mixture was used as the oxidant in
the DTF experiments to simulate O2 /recycled flue gas
combustion. Two types of O2 /CO2 mixtures with volumetric mixture ratios of O2 : CO2 = 1 : 9 and 1 : 4
were employed. For comparison purpose, combustion in
O2 /N2 mixture with the gas composition of O2 : N2 =
1 : 9 and 1 : 4 was also carried out. Combustion experiment in the O2 /N2 mixture of O2 : N2 = 1 : 4 simulated
the combustion in air (hereafter called air combustion).
During the experiments, the furnace tube temperature
was set at 1300 ◦ C.
All ash samples generated from the four experimental cases were characterized by a 57 Fe Mössbauer
spectroscopy to study the transformation of pyrite.
Room temperature Mössbauer transmission spectra
were recorded with a constant acceleration spectrometer of standard design using a 57 Co/Pd source. The
spectrometer was calibrated with a standard α-Fe foil
and the reported isomer shift was relative to the center of the α-Fe spectrum at room temperature. The
spectral Mössbauer parameters – i.e. isomer shift (I.S.),
quadrupole splitting (Q.S.) and magnetic hyperfine field
(M.H.F.) – were determined by computer-fitting sets of
Lorentzian lines to the experimental data using standard least-square method. The iron-containing phases
present in ash samples were identified by comparing
their Mössbauer parameters with those reported in the
literature for iron-bearing species in coal and coal ash
(e.g., Refs [19–22]) in combination with using XRD
analysis to confirm the phases. The percentages of
the total iron contained in each phases identified were
determined from the areas under appropriate Mössbauer
absorption peaks.[19] The size distribution of the residue
Table 2. Composition of the pyrite powder.
Mass fraction of minerals
Molar fraction of elements
Constituent
Pyrite
Quartz
Kaolinite
Calcite
Si
Al
Fe
Ca
S
Value
0.464
0.138
0.121
0.277
0.319
0.72
0.147
0.211
0.197
 2009 Curtin University of Technology and John Wiley & Sons, Ltd.
Asia-Pac. J. Chem. Eng. 2010; 5: 304–309
DOI: 10.1002/apj
305
306
C. SHENG ET AL.
Asia-Pacific Journal of Chemical Engineering
ash particles was analyzed by using a Malvern Mastersizer 2000 in order to study the impact of combustion
gas atmosphere on ash formation behaviors, particularly
the fragmentation of excluded pyrite.
RESULTS AND DISCUSSION
Transformation of excluded pyrite
The Mössbauer analysis results of the residue ashes
from four experimental cases together with those of
the mixed sample of pulverized coal and pyrite mineral
powder are summarized in Table 3. As seen in Table 3,
most of the iron (i.e. 94%) were present as pyrite in
the combustion sample. Whereas the rest of the iron
was present as unassigned species, likely including iron
silicates and oxides.
It has been well documented that in oxidizing condition, pyrite decomposes to pyrrhotite, then oxidizes
to a molten FeO–FeS phase and further oxidizes to
magnetite and hematite.[13 – 15] If associated with silicate minerals, pyrite can also transform into glass silicate through their intermediate products melting and
combining with silicates to form Fe2+ - and Fe3+ -glass
silicates.[16] As was expected, the iron phases identified
in all the ashes were complex, including iron oxides and
Fe3+ -glass silicate (see Table 3). It implies that pyrite
transformation took two paths in both atmospheres.
When comparing the pairs of the ashes produced in
O2 /CO2 and O2 /N2 combustion, the iron phases identified were same but with different relative percentages.
In the ashes formed in both atmospheres, about 45–48%
of iron occurred as Fe3+ -glass silicate that was expected
to be formed through the combination of the intermediate products of pyrite and silicates in the raw pyrite
mineral. It means that the reaction temperature of pyrite
particles was quite high for the intermediate products to
melt and coalescence during their transformation processes. The rest of the pyrite transformed into oxides
following the oxidization path.
When comparing the ashes formed in O2 /N2 combustion and O2 /CO2 combustion with a mixture ratio
of 1 : 9, there are almost no differences in both the
fraction of iron in Fe3+ -glass silicate and the total
fraction of iron in oxides. Only slightly less iron was
present in Fe3+ -glass silicate of the ash formed in
O2 /CO2 combustion. Nevertheless, there is a considerable difference in the iron distribution among three
oxide species: more iron present in hematite and octahedral magnetite while less iron present in tetrahedral
magnetite in the ash formed in O2 /CO2 combustion
with the same oxygen concentration. The difference can
be attributed to the difference in the reaction temperature of pyrite. During the transformation of pyrite in
oxidizing condition of O2 /N2 combustion, the temperatures of pyrite particles can overshoot gas temperature
due to the exothermic oxidation of pyrrhotite, the product of pyrite decomposition.[14] In O2 /CO2 condition,
the pyrite particles were expected to achieve lower temperatures than those in O2 /N2 combustion because of
Table 3. Mössbauer parameters of iron-bearing phases in original sample and DTF ashes.
Sample
Coal + Pyrite
Ash
1300 ◦ C, O2 : N2 = 1 : 9
1300 ◦ C, O2 : CO2 = 1 : 9
1300 ◦ C, O2 : N2 = 1 : 4
1300 ◦ C, O2 : CO2 = 1 : 4
I.S. (mm/s)
Q.S. (mm/s)
0.33
0.40
0.61
1.96
0.39
0.29
0.71
0.30
0.36
0.33
0.59
0.29
0.37
0.32
0.73
0.30
0.37
0.29
0.79
0.29
−0.18
−0.10
0.23
1.17
−0.18
−0.07
0.04
1.15
−0.19
−0.10
0.39
1.14
−0.20
−0.11
0.31
1.19
M.H.F. (kOe)
514
486
466
513
488
460
516
491
465
515
489
464
Assignment
Fe (%)
Pyrite
Unassigned
94.0
6.0
Hematite
Magnetitea
Magnetiteb
Fe3+ -glass silicate
Hematite
Magnetitea
Magnetiteb
Fe3+ -glass silicate
Hematite
Magnetitea
Magnetiteb
Fe3+ -glass silicate
Hematite
Magnetitea
Magnetiteb
Fe3+ -glass silicate
13.6
22.7
15.8
47.8
19.6
12.5
22.2
45.7
20.8
26.5
7.4
45.3
19.4
26.3
9.6
44.7
a
Tetrahedral.
b
Octahedral.
 2009 Curtin University of Technology and John Wiley & Sons, Ltd.
Asia-Pac. J. Chem. Eng. 2010; 5: 304–309
DOI: 10.1002/apj
TRANSFORMATION BEHAVIORS OF EXCLUDED PYRITE DURING O2 /CO2
 2009 Curtin University of Technology and John Wiley & Sons, Ltd.
(a) 50
40
Fe, %
the higher thermal capacity of CO2 than that of N2
and the lower mass diffusivity of O2 in CO2 than in
N2 . The lower particle temperatures certainly slowed
the oxidation of pyrrhotite and the transformation from
octahedral magnetite to tetrahedral magnetite. Additionally, considerably more hematite formed in the O2 /CO2
ash (see Table 3) was also due to the lower reaction
temperature, which thermodynamically favored the oxidation of magnetite to hematite.[14] Additionally, it was
also expected that the lower particle temperatures also
decreased the extent of the melting of the minerals
decreased, which might lead to less iron melting into
silicates during O2 /CO2 combustion.
It can be seen in Table 3 that in O2 /N2 combustion, increasing the oxygen concentration increased the
transformation from octahedral magnetite to tetrahedral
magnetite and enhanced the oxidation from magnetite
to hematite. The reasons are that high oxygen concentration enhanced the oxidation of pyrite and also
thermodynamically favored the oxidation of magnetite
to hematite at higher reaction temperature. In contrast,
increasing oxygen concentration in O2 /N2 combustion
only slightly decreased the iron containing in glass silicate. The reason is that, although increasing oxygen
concentration increased the reaction temperatures of
pyrite particles implying the enhancement of melting
and coalescence of minerals, higher oxygen concentration also enhanced the transformation of pyrite through
the oxidation path and the fragmentation of the mineral
particles. In O2 /CO2 combustion, increasing oxygen
concentration had similar impacts on the transformations of pyrite, i.e. increasing the transformation from
octahedral magnetite to tetrahedral magnetite. Therefore, increasing the oxygen concentration resulted in
the iron distributions of the ashes formed in two atmospheres turning to be similar (see Table 3).
It is worthy to be noted that when studying the
transformations of iron minerals in pulverized coals,[10]
O2 /CO2 combustion was found to result in more
iron glass silicates formed in the ash in comparison
with O2 /N2 combustion in same conditions, as shown
in Fig. 1(b). The difference in the iron distribution
between the ashes formed in two atmospheres was
attributed between the ashes formed in two atmospheres
to the impacts of the changing combustion atmosphere
on the included iron minerals, in particular the included
pyrite. However, the deduction was not strongly supported by the experiments because the association of
pyrite with coal matrix was not distinguished in that
study. The observations of the impact of changing gas
atmosphere on the iron content in glass silicate in the
present work (see Table 3 and Fig. 1(a)) were contrary
to those observed in the previous work: the iron contents
of glass silicate in the ashes formed in O2 /CO2 combustion were almost the same as those in the ashes formed
in O2 /N2 combustion at the same conditions. Even the
slight differences described earlier are considered, the
30
20
10
0
Hematite
Tetrahedral
magnetite
Hematite
Tetrahedral
magnetite
Octahedral
magnetite
Fe3+ glass
silicate
(b) 50
40
Fe, %
Asia-Pacific Journal of Chemical Engineering
30
20
10
0
Octahedral
magnetite
Fe3+ glass
silicate
Figure 1. Comparison of iron distributions in the ashes
of excluded pyrite (a) with that in the ashes of pulverized
coal (b). Open and filled bars denote the ashes formed in
O2 : N2 = 1 : 4 and O2 : CO2 = 1 : 4, respectively.
ash formed in O2 /CO2 combustion had less iron present
in glass silicate than the ash formed in O2 /N2 combustion, which was also contrary to those observed in the
combustion of pulverized coal. The discrepancy can be
attributed to the dependence of pyrite transformation
behaviors on its occurrence in coal particles. In the
present work, pyrite, although it was actually associated with other minerals (e.g. silicates), was physically
mixed in the pulverized coal. During the combustion
process, the pyrite particles behaved independently of
the combustion of coal particles because of the low
particle concentration involved in the DTF. The results
in Table 3 and Figure 1(a) indicated that the impact of
varying the combustion atmosphere from O2 /N2 combustion to O2 /CO2 combustion did not change the iron
content in glass silicate despite the slight differences.
The reason is that the difference of pyrite particle temperatures, consequently the melting behaviors, in the
two atmospheres was not significant because of the
low reaction rate and low reaction heat of pyrite oxidation. For coal included pyrite, the variation of gas
atmosphere not only changes the combustion temperatures of char particles, but also significantly changes
the in-particle gas atmosphere (e.g. modeling work of
Krishnamoorthy and Veranth[23] indicates that O2 /CO2
combustion results in high CO concentration in the
particles) which has a significant impact on the transformation of iron-containing species. Therefore, it can be
concluded that the variation from O2 /N2 combustion to
O2 /CO2 combustion does not significantly influence on
Asia-Pac. J. Chem. Eng. 2010; 5: 304–309
DOI: 10.1002/apj
307
C. SHENG ET AL.
Asia-Pacific Journal of Chemical Engineering
the transformation of excluded pyrite during pulverized
coal combustion. It can also be confirmed that the variation of combustion atmosphere mainly influences the
transformation of included iron minerals through influencing the combustion of coal particles.
FRAGMENTATION OF PYRITE MINERAL
PARTICLES
The size distributions of the residue ash particles formed
in four experimental cases are presented in Fig. 2 and
the size distribution of the mixture sample is also shown
for comparison. It can be seen that the mixture of coal
and pyrite has a narrow size distribution and most of
the particles are in the size range of 100–300 µm. In
contrast, the sizes of the ash particles formed in all combustion cases are much smaller and most particles are
less than 100 µm, but the size distributions are widened.
Because of the low ash content of the low density pulverized coal used, after complete combustion, the ash
formed from the pulverized coal was estimated to take
a part of less than 20% of the total ash formed from the
mixture. It means that the majority of the residue ash
particles collected from the experiments was originated
from the pyrite mineral. The significant decrease in the
sizes of the ash particles formed in four experimental
cases in comparison with that of the coal–pyrite mixture
implies that significant fragmentation of the pyrite mineral particles occurred during the pyrite transformation.
Calcite might make its contribution to the fragmentation, but the extent was expected to be less than that of
pyrite. The reasons are that the content of calcite in the
sample was much less than that of pyrite and the fragmentation extent of calcite was less than that of pyrite
at the same condition (Ref. [24]).
In comparison with those formed in O2 /N2 combustion, the ash particles formed in O2 /CO2 combustion of
both oxygen concentrations were coarser (see Figure 2).
15
Coal+FeS2
O2:N2 =1:9
O2:CO2 =1:9
O2:N2 =1:4
O2:CO2 =1:4
12
Volume (%)
308
9
In particular, considerably less particles of smaller than
30 µm were formed in O2 /CO2 combustion. It implies
that less pyrite fragmentation occurred during the transformation than that in O2 /N2 combustion. Increasing
the oxygen concentration did not change the difference although the ash particles become slightly finer
in both atmospheres. The reason is that, whether in
O2 /N2 combustion or in O2 /CO2 combustion, increasing oxygen concentration increased the reaction rate
of pyrite, which led to more particle fragmentation.
When compared with O2 /N2 combustion at the same
oxygen concentration, less particle fragmentation in
O2 /CO2 combustion implies larger iron-containing particle formed, which might increase the slagging propensity of excluded pyrite.
CONCLUSIONS
The following conclusions were drawn from the present
study:
1. In comparison with O2 /N2 combustion, O2 /CO2
combustion did not significantly affect the transformation of excluded pyrite. It did not change the
iron species formed from excluded pyrite and the
iron present in glass silicate formed in the ashes but
slowed the oxidation of pyrite products to iron oxides
because of the lower reaction temperature of pyrite
in O2 /CO2 combustion.
2. It was confirmed that the impact of combustion
gas atmosphere variation from O2 /N2 combustion
to O2 /N2 combustion on excluded pyrite was significantly different from that on included pyrite. The
O2 /CO2 combustion had a significant impact on
included pyrite transformation because of its impact
on the combustion of coal particles.
3. The fragmentation of mineral pyrite was observed in
the combustion of both atmospheres. The O2 /CO2
combustion decreased the extent of fragmentation
as compared with O2 /N2 combustion at the same
oxygen concentration. Increasing oxygen concentration enhanced the fragmentation of pyrite particles
in both atmospheres.
6
Acknowledgements
3
The financial support from National Science Foundation of China under the projects of No. 50576012 and
No. 50721140649 was acknowledged. Partial support
from the Opening Foundation of Key Laboratory of
nuclear analysis techniques (Shanghai Division), Chinese Academy of Sciences, for using the ash analysis
facilities was also acknowledged.
0
100
101
102
Diameter (micron)
Figure 2. Size distributions of the DTF ashes and
the experimental sample.
 2009 Curtin University of Technology and John Wiley & Sons, Ltd.
Asia-Pac. J. Chem. Eng. 2010; 5: 304–309
DOI: 10.1002/apj
Asia-Pacific Journal of Chemical Engineering
TRANSFORMATION BEHAVIORS OF EXCLUDED PYRITE DURING O2 /CO2
REFERENCES
[1] T.F. Wall. Proc. Combust. Inst., 2007; 31, 31–37.
[2] B.J.P. Buhre, L.K. Elliott, C.D. Sheng, R.P. Gupta, T.F. Wall.
Prog. Energy Combust. Sci., 2005; 31, 283–307.
[3] A. Molina, C.R. Shaddix. Proc. Combust. Inst., 2007; 31,
1905–1912.
[4] T. Kiga, S. Takano, N. Kimura, K. Omata, M. Okawa,
T. Mori. Energy Convers. Manage., 1997; 38, S129–S134.
[5] T. Suda, K. Masuko, J. Sato, A. Yamamoto, K. Akazaki. Fuel,
2007; 86, 2008–2015.
[6] J.J. Murphy, C.R. Shaddix. Combust. Flame, 2006; 144,
710–729.
[7] Y.W. Tan, E. Croiset, M.A. Douglas, K.V. Thambimuthu.
Fuel, 2005; 85, 507–512.
[8] H. Liu, R. Zailani, B.M. Gibbs. Fuel, 2005; 84, 833–840.
[9] C.D. Sheng, Y.H. Lu, X.P. Gao, H. Yao. Energy Fuels, 2007;
21, 435–440.
[10] C.D. Sheng, Y. Li. Fuel, 2008; 87, 1297–1305.
[11] E. Raask. Mineral Impurities in Coal Combustion, Hemisphere
Publishing Corporation: New York, 1985.
[12] R.W. Bryers. Prog. Energy Combust. Sci., 1996; 22, 29–120.
 2009 Curtin University of Technology and John Wiley & Sons, Ltd.
[13] G.P. Huffman, F.E. Huggins, A.A. Levasseur, O. Chow,
S. Srinivasachar, A.K. Mehta. Fuel, 1989; 68, 485–490.
[14] S. Srinivasachar, A.A. Boni. Fuel, 1989; 68, 829–836.
[15] S. Srinivasachar, J.J. Helble, A.A. Boni. Prog. Energy Combust. Sci., 1990; 16, 281–292.
[16] L.E. Bool III, T.W. Peterson, J.O.L. Wendt. Combust. Flame,
1995; 100, 262–270.
[17] A.R. McLennan, G.W. Bryant, C.W. Bailey, B.R. Stanmore,
T.F. Wall. Energy Fuels, 2000; 14, 308–315.
[18] D. Yu, M.H. Xu, Y. Yu, X. Liu. Energy Fuels, 2005; 19,
2488–2494.
[19] G.P. Huffman, F.E. Huggins. Fuel, 1978; 57, 592–604.
[20] C.C.
Hinckley,
G.V.
Smith,
H.
Twardowska,
M. Saporoschenko, R.H. Shiley, R.A. Griffen. Fuel,
1980; 59, 161–165.
[21] S.P. Taneja, C.H.W. Jones. Fuel, 1984; 63, 695–701.
[22] L.C. Ram, P.S.M. Tripathi, S.P. Mishra. Fuel Process. Technol., 1995; 42, 47–60.
[23] G. Krishnamoorthy, J.M. Veranth. Energy Fuels, 2003; 17,
1367–1371.
[24] L. Yan, R.P. Gupta, T.F. Wall. Energy Fuels, 2001; 15,
389–394.
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DOI: 10.1002/apj
309
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