Investigation of deep catalytic cracking of various model compounds of different classes of light hydrocarbons on a mesoporous catalyst based on ZSM-5 zeolite

Article abstract of DOI:10.1134/S0965544117020190

The catalytic cracking performance of light hydrocarbon model compounds (1-hexene, n-octane, i-octane, ethylcyclohexane and ethylbenzene) over a mesoporous catalyst based on ZSM-5 zeolite was analyzed and compared using a microscale apparatus with a fixed-bed reactor. The effects of reaction temperature and weight hourly space velocity (WHSV) on feed conversion and the yields of ethene and propene were investigated. The results showed that with increased reaction temperature, the conversion of model compounds increased monotonically, and that of 1-hexene was close to 100% above 660°C; the yield of ethene plus propene of n-octane, i-octane and ethylcyclohexane increased continuously, while that of 1-hexene and ethylbenzene passed through maximum. With increased WHSV, the yield of ethene plus propene of ethylbenzene increased continuously, and that of the other model compounds decreased continuously. Through comprehensive analysis of the data, it is indicated that 1-hexene exhibited the highest cracking performance, followed by n-octane and ethylcyclohexane, whereas i-octane and ethylbenzene exhibited the lowest.

Full text of DOI:10.1134/S0965544117020190

ISSN 0965-5441, Petroleum Chemistry, 2017, Vol. 57, No. 3, pp. 209–214. © Pleiades Publishing, Ltd., 2017.
Published in Russian in Neftekhimiya, 2017, Vol. 57, No. 2, pp. 149–155.
Investigation of Deep Catalytic Cracking of Various Model
Compounds of Different Classes of Light Hydrocarbons
1
on a Mesoporous Catalyst Based on ZSM-5 Zeolite
G. L. Liu, Y. D. Wang, R. Zhang, H. Y. Liu, Z. C. Liu, and X. H. Meng*
State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Beijing 102249, PR China
*
e-mail: mengxh@cup.edu.cn
Received March 25, 2016
Abstract⎯ The catalytic cracking performance of light hydrocarbon model compounds (1-hexene, n-octane,
i-octane, ethylcyclohexane and ethylbenzene) over a mesoporous catalyst based on ZSM-5 zeolite was ana-
lyzed and compared using a microscale apparatus with a fixed-bed reactor. The effects of reaction tempera-
ture and weight hourly space velocity (WHSV) on feed conversion and the yields of ethene and propene were
investigated. The results showed that with increased reaction temperature, the conversion of model com-
pounds increased monotonically, and that of 1-hexene was close to 100% above 660°C; the yield of ethene
plus propene of n-octane, i-octane and ethylcyclohexane increased continuously, while that of 1-hexene and
ethylbenzene passed through maximum. With increased WHSV, the yield of ethene plus propene of ethylben-
zene increased continuously, and that of the other model compounds decreased continuously. Through com-
prehensive analysis of the data, it is indicated that 1-hexene exhibited the highest cracking performance, fol-
lowed by n-octane and ethylcyclohexane, whereas i-octane and ethylbenzene exhibited the lowest.
Keywords: catalytic cracking, light hydrocarbon, ethene, propene, model compounds
DOI: 10.1134/S0965544117020190
[
23–28]. Among them, light hydrocarbons have high
Ethene and propene are important basic organic
chemical raw materials [1–3]. Steam cracking is the
main process in ethene and propene production but
has a high energy consumption. The control range of
the yield ratio of propene to ethene (P/E) is limited,
and the P/E ratio depends greatly on the feed type [4–
light olefin yields and low coking rate. Naphtha is an
important catalytic cracking feedstock of light hydro-
carbons. The group compositions in naphtha include
alkanes, alkenes, naphthenes and aromatics.
Muraza et al. studied the reaction process of pro-
pene production by n-hexane catalytic cracking over a
hierarchical porous MTT molecular sieve catalyst with
high activity, and achieved a P/E ratio of 2.5 [29]. The
kinetics of n-hexane catalytic cracking over an MFI
zeolite at 475 to 650°C was studied by Nakasaka et al.,
and the activation energy at high temperatures (550–
6]. The production capacity of steam cracking is
unable to meet the growing demand for light olefins
worldwide, especially propene [7–9].
Catalytic cracking of hydrocarbons has several
advantages such as low energy consumption, high
yields of olefins and high P/E ratio compared with
steam cracking, thus making it a beneficial supple-
ment to steam cracking [10, 11]. Zeolite catalysts are
widely used in catalytic cracking. Among them, the
ZSM-5 catalyst has remarkably improved light olefin
yields [12–17]. Several mature preparation methods
for ZSM-5 zeolite exist. Preparation methods mainly
include hydrothermal synthesis [18] solvothermal syn-
thesis [19], dry gel conversion method [20], ionother-
mal synthesis [21] and solvent-free synthesis [22]. The
diversity of mature preparation methods of ZSM-5
catalysts allows the study and application of the crack-
ing catalyst. Catalytic cracking feedstocks mainly
include light hydrocarbons and heavy hydrocarbons
6
(
50°C) was greater than that at low temperatures
475–550°C) [30]. Corma et. al. examined the effect
of steam on n–heptane catalytic cracking. Although
the presence of steam negatively affected the perfor-
mance of the catalyst, it could greatly reduce the for-
mation of hydrogen, methane and coke precursors
[
31]. Many studies reported on the catalytic cracking
performance of light alkanes, but only a few compared
the cracking performance of different kinds of light
hydrocarbons [32]. Systematic research on the crack-
ing performance of different hydrocarbons will con-
tribute to the deeper understanding of light hydrocar-
bon cracking and the development of new types of
cracking catalysts and processes.
1
The article is published in the original.
209

2
10
LIU et al.
pumped by different pumps. When the catalyst bed
Table 1. Physicochemical properties of the catalyst
temperature reached the setting temperature, a vari-
able amount of distilled water was pumped into the
furnace to form steam, which then entered the reactor.
The light hydrocarbon feed was pumped into the reac-
tor once the reactor temperature stabilized. Cracking
reactions took place as the feed came into contact with
the catalyst. Gas and liquid collection was started, and
time was recorded once reaction temperature stabi-
lized again. The reaction product was cooled and sep-
arated into liquid and gas samples via the product sep-
aration and collection systems. The liquid sample was
collected in a condensate bottle, and the gas sample in
a gas collecting bottle. The equipment exhibited good
repeatability and stability, with a mass balance of over
Parameter
Diameter, mm
Length, mm
Value
2.0
2.5
Particle density, g/cm3
Packing density, g/cm3
SiO /Al O molar ratio
1
.274
.754
3.6
0
a
3
2
2
3
2
371
Specific surface area, m /g
3
0.38
Total pore volume, cm /g
3
0.24
Mesopore volume, cm /g
a
Measured by XRF.
97 wt %.
The activity stability of the catalyst was verified at a
In the present paper, the catalytic cracking perfor-
mance of various model compounds of different
classes of naphtha compositions was studied systemat-
ically. The effects of reaction temperature and weight
hourly space velocity (WHSV) on feed conversion, the
yields of ethene and propene, and the composition of
the liquid products were investigated. The catalytic
cracking performance of different model compounds
was analyzed and compared.
–1
WHSV of 4.2 h and a steam to oil weight (S/O) ratio
of 0.36 using 1-hexene as the feedstock. The catalyst
maintained good activity and selectivity of ethene and
propene, and the coke yield was lower than 0.1 wt %
after the input mass of 1-hexene reached 12.5 times of
the catalyst mass. In other studies, the handling
mass of light hydrocarbons was much lower than that
of 1-hexene in the verification experiment, thus the
deactivation of the catalyst and the coke yield were
neglected.
1. EXPERIMENTAL
1.1. Feedstock and Catalyst
1.3. Analytical Methods
n-Octane (AR, Tianjin Fuchen Chemical Reagents
Factory), i-octane (2,2,4-trimethylpentane, 99%,
Aladdin Industrial Corporation), 1-hexene (97%,
Aladdin Industrial Corporation), ethylcyclohexane
The gas sample was analyzed using an Agilent 6890
gas chromatograph equipped with a HP–PLOT Al O
2
3
capillary column (50 m × 530 μm × 15 μm), a 1.8 m ×
1
/8 molecular sieve packed column, a 3 m × 1/8
(
99%, Aladdin Industrial Corporation) and ethylben-
molecular sieve packed column, a 1.8 m × 1/8 porous
polymeric packed column, a 0.9 m × 1/8 porous poly-
meric packed column, a thermal conductivity detector
zene (99.8%, Anhydrous Grade, Aladdin Industrial
Corporation) were selected as the model compound of
straight-chain alkanes, branched alkanes, alkenes,
naphthenes and aromatics of naphtha group composi-
tions, respectively. The catalyst was a mesoporous cat-
alyst based on ZSM-5 zeolite developed specifically by
China University of Petroleum for cracking light
hydrocarbon feedstocks in a fixed-bed reactor. The
preparation method of the catalyst was reported in the
literature [33, 34]. The main physicochemical proper-
ties are summarized in Table 1.
(
TCD), a flame ionization detector (FID) and a
ChemStation software. Volume percentages of gas
components could be obtained. The state equation of
ideal gas was then used to convert the volume percent-
ages to weight yields with the gas sample volume.
The liquid sample was analyzed using an SP 3420
gas chromatograph fitted with a PONA capillary col-
umn (50 m × 250 μm × 0.25 μm) and a FID. PONA
analytical software was used to obtain the weight per-
centages of the liquid sample components. Compo-
nent yields were calculated using the mass of the liquid
sample.
1.2. Experimental Apparatus and Procedure
The experiments for the catalytic cracking of light
hydrocarbons were performed in a microscale fixed-
bed reactor. The apparatus includes five main sec-
tions: oil and steam input mechanisms, a reaction
zone, a temperature control system, a product separa-
tion system and a collection system. The reactor is
2. RESULTS AND DISCUSSION
2
.1. Effect of Reaction Temperature
on Cracking Performance
4
0 cm long with a diameter of 1.3 cm.
Experiments were conducted in batches. Ten grams version and the yields of ethene and propene for five
of the catalyst was placed in the reactor. Distilled water model compounds was investigated at a WHSV of
The effect of reaction temperature on the feed con-
–1
and feedstock were kept in separate vessels and 4.2 h and an S/O ratio of 0.36.
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INVESTIGATION OF DEEP CATALYTIC CRACKING
211
35
30
25
2
5
20
20
15
1
5
n-Octane
i-Octane
n-Octane
i-Octane
10
1-Hexene
10
5
1-Hexene
Ethulcyclohexane
Ethylbenzene
Ethulcyclohexane
Ethylbenzene
5
0
600
620
640
660
680
600
620
640
660
680
Reaction temperature, °C
Reaction temperature, °C
Fig. 1. Effect of reaction temperature on ethene yield
WHSV, 4.2 h–1; S/O ratio, 0.36).
Fig. 2. Effect of reaction temperature on propene yield
–1
(
(WHSV, 4.2 h ; S/O ratio, 0.36).
With increased reaction temperature, the conver- pene yield, which indicated that the main reaction was
sion of n-octane, i-octane, ethylcyclohexane and eth- the side chain scission generating benzene and ethene.
ylbenzene increased continuously and reached 97.6, In addition, propene was formed by the secondary
6
2.2, 89.2 and 97.8% at 680°C, respectively. Ethylben- reactions of ethene polymerization and then cracking.
zene conversion was high since the cracking reaction The rank order of the propene yield of the different
of ethylbenzene can take place easily, generating ben- model compounds was: 1-hexene > n-octane > ethyl-
zene and ethene [35]. The conversion of 1-hexene was cyclohexane > i-octane > ethylbenzene.
high and increased slightly with increased reaction
The effect of reaction temperature on the yield of
temperature; it approached 100% above 660°C. The
ethene plus propene is shown in Fig. 3. With increased
rank order of the conversion of the different model
reaction temperature, the yield of ethene plus propene
compounds was: 1-hexene > n–octane > ethylben-
of n-octane, i-octane and ethylcyclohexane increased
zene > ethylcyclohexane > i-octane.
continuously, reaching 51.0, 31.3 and 40.1 wt % at
The effect of reaction temperature on ethene yield 680°C, respectively. The yield of ethene plus propene
is shown in Fig. 1. With increased reaction tempera- of 1-hexene and ethylbenzene passed through a maxi-
ture, the ethene yield of 1-hexene, n-octane, i-octane mum of 61.9 wt % at 660°C and 22.6 wt % at 620°C,
and ethylcyclohexane increased continuously, reach- respectively. The rank order of the yield of ethene
ing 26.0, 24.7, 11.4 and 18.9 wt % at 680°C, respec- plus propene of the different model compounds was:
tively. The ethene yield of ethylbenzene passed 1-hexene > n-octane > ethylcyclohexane > i-octane.
through a maximum of 20.2 wt % at 620°C because the 1-Hexene had the best cracking performance among
side chain scission generating benzene and ethene was all model compounds. Ethylbenzene conversion was
the main reaction at a low reaction temperature. Addi- high, but the yield of ethene plus propene was low.
tionally, the secondary reaction degree of This finding indicated that more by-products were
ethene increased at a high reaction temperature, formed when aromatic hydrocarbons were used as
resulting in decreased ethene yield. The ethene yield feedstocks and that secondary reactions intensified
rank order of different model compounds was: 1-hex- with increased temperature.
ene > n-octane > ethylcyclohexane > i-octane.
The liquid products of n-octane were mainly
Figure 2 shows the influence of reaction tempera- n-alkanes, alkenes and aromatics. N-Alkanes were
ture on propene yield. The propene yield of n-octane mainly non-cracked feedstock. Alkenes were mainly
and i-octane increased continuously with increased pentene and hexene. Aromatics were mainly benzene,
reaction temperature, reaching 26.3 and 19.9 wt % at toluene and xylene. The monomolecular reaction gen-
6
80°C, respectively. The propene yield of 1-hexene erating octyl carbenium ion was the main reaction in
and ethylcyclohexane passed through a maximum of n-octane cracking process. The β-cleavage reaction of
6.5 and 22.3 wt % at 660°C, respectively, because octyl carbenium ion occured generating alkenes. Sec-
3
secondary reactions of propene intensified at a high ondary reactions such as hydrogen transfer and aro-
reaction temperature. The propene yield of ethylben- matization occured for small molecular alkenes. The
zene decreased continuously, and the maximum value aromatization reactions of different octyl carbenium
was only 4.6 wt % at 600°C. In the catalytic cracking of ions could also occur generating the corresponding
ethylbenzene, ethene yield was much higher than pro- aromatics. Therefore, the yields of alkenes and aro-
PETROLEUM CHEMISTRY Vol. 57 No. 3 2017

2
12
LIU et al.
n-Octane
i-Octane
matics were mainly benzene and unreacted ethylben-
6
0
0
1-Hexene
zene. The molar ratio of benzene to ethene in cracking
products of ethylbenzene was close to 1 at low reaction
temperature. With increased reaction temperature, the
molar ratio of benzene to ethene increased, reaching
Ethulcyclohexane
Ethylbenzene
5
1
.7 at 680°C. The liquid product group compositions
40
30
20
of different model compounds at 600°C are shown in
Table 2.
2.2. Effect of WHSV on Cracking Performance
The influence of WHSV on ethene and propene
yields in the catalytic cracking of model compounds
was investigated at a reaction temperature of 660°C
and an S/O ratio of 0.36.
10
600
620
640
660
680
Reaction temperature, °C
Figure 4 shows the effect of WHSV on ethene yield.
With increased WHSV, the ethene yield of 1-hexene,
n-octane, i-octane and ethylcyclohexane decreased
continuously, reaching 25.4, 21.6, 9.7 and 17.5 wt % at
Fig. 3. Effect of reaction temperature on the yield of
ethene plus propene (WHSV, 4.2 h–1; S/O ratio, 0.36).
–1
4
h , respectively. WHSV can reflect the contact time
matics in the liquid products of n-octane were rela-
tively high. The liquid products of i-octane were
mainly non-cracked feedstock. With increased reac-
tion temperature, the yield of i-octane in the liquid
products decreased continuously, which indicated
that the cracking ability of i-octane enhanced gradu-
ally with increased reaction temperature. The liquid
products of 1-hexene were mainly aromatics and
between the feedstock and catalyst. For high WHSV,
the reaction extent of the feedstock is small. The above
results indicated that low WHSV was conducive
to the conversion of the mentioned model
compounds into ethene; however, the ethene yield of
ethylbenzene increased continuously, reaching
–1
1
9.4 wt % at 6.79 h . This showed that large WHSV
was beneficial to the cracking of ethylbenzene to
ethene. The ethene yield rank order of different model
compounds was: 1-hexene > n-octane > ethylcyclo-
hexane > i-octane. It was consistent with the rank
order of ethene yield of different model compounds at
different reaction temperatures.
alkenes. The aromatics were mainly toluene and C
8
aromatics. The alkenes were mainly pentene and hex-
ene. According to the analysis of cracking products of
1
-hexene, both the monomolecular reaction and
bimolecular reaction occured in 1-hexene cracking
process. With increased reaction temperature, the
yield of aromatics in liquid products decreased,
The effect of WHSV on propene yield is shown in
which indicated that the bimolecular reaction degree Fig. 5. With increased WHSV, the propene yield of n-
of 1-hexene decreased with increased reaction tem- octane, ethylcyclohexane, and so-octane decreased
perature. The liquid products of ethylcyclohexane continuously, reaching 25.1, 22.3, and 17.4 wt % at
–1
were mainly naphthenes, alkenes and aromatics. 4 h , respectively. And the propene yield of n-octane
Naphthenes were mainly non-cracked feedstock. and ethylbenzene varied slightly at approximately 25
Alkenes were mainly pentene. Aromatics were mainly and 2 wt %, respectively. The above results indicated
benzene, toluene and xylene. The ring opening reac- that low WHSV was conducive to the conversion of the
tion generating octyl carbenium ion was the main mentioned model compounds into propene. In addi-
reaction in ethylcyclohexane cracking process. The tion, the ethene yield of ethylbenzene was higher than
cracking and aromatization reactions of octyl carbe- the propene yield under different WHSV, which indi-
nium ion occured generating pentene, aromatics, et al. cated again that the side chain scission generating ben-
The liquid products of ethylbenzene were mainly aro- zene and ethene was the main reaction in the catalytic
matics, whose relative content was over 97%. The aro- cracking of ethylbenzene. With decreased WHSV, the
Table 2. Liquid product group compositions of different model compounds at 600°C
Relative content, wt %
Model compounds
n-paraffins
i-paraffins
olefins
naphthenes
aromatics
n-Octane
-Hexene
Ethylcyclohexane
Ethylbenzene
53.0
1.4
1.5
2.5
2.5
2.1
0.2
13.9
18.1
8.9
0.7
1.1
46.1
0.1
29.9
77.0
41.4
97.5
1
0.7
1.6
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INVESTIGATION OF DEEP CATALYTIC CRACKING
213
n-Octane
4
0
i-Octane
-Hexene
2
5
0
1
Ethulcyclohexane
Ethylbenzene
35
n-Octane
i-Octane
1-Hexene
30
25
20
2
Ethulcyclohexane
Ethylbenzene
15
15
10
10
5
5
0
4
.0 4.5 5.0 5.5 6.0 6.5 7.0 7.5
4
.0 4.5 5.0 5.5 6.0 6.5 7.0 7.5
–1
WHSV, h
–1
WHSV, h
Fig. 4. Effect of WHSV on ethene yield (reaction tempera-
ture, 660°C; S/O ratio, 0.36).
Fig. 5. Effect of WHSV on propene yield (reaction tem-
perature, 660°C; S/O ratio, 0.36).
propene yield of 1-hexene passed through a maximum
3
. CONCLUSIONS
–1
of 36.8 wt % at 4.82 h , which indicated that the yield
of propene as the primary product increased firstly
and then decreased with increased reaction time
because the secondary reaction of propene intensified.
Appropriate increase of WHSV could shorten the con-
tact time between the primary product and catalyst,
thereby reducing the occurrence of the secondary
reaction. Therefore, for 1-hexene, it was necessary to
(
1) The conversion of each model compound
increased continuously with increased reaction tem-
perature. The conversion of 1-hexene was the highest,
and that of i-octane was the lowest among the five
model componds.
(2) With increased reaction temperature, the
control WHSV at the appropriate level in order to yield of ethene plus propene of n-octane, i-octane and
obtain high propene yield. The rank order of the pro- ethylcyclohexane increased continuously, while that
pene yield of the different model compounds was: of 1-hexene and ethylbenzene passed through maxi-
1
-hexene > n-octane > ethylcyclohexane > i-octane > mum.
ethylbenzene. It was consistent with the rank order of
propene yield of different model compounds at differ-
ent reaction temperatures.
Figure 6 shows the influence of WHSV on the yield
of ethene plus propene. With increased WHSV,
the yield of ethene plus propene of 1-hexene, n-oc-
tane, i-octane and ethylcyclohexane decreased con-
tinuously, reaching 61.9, 46.7, 27.1 and 39.8 wt % at
7
6
5
4
3
0
0
0
0
0
n-Octane
i-Octane
–1
4
h , respectively. This indicated that the mentioned
1-Hexene
Ethulcyclohexane
Ethylbenzene
model compounds cracking ability to light olefins was
reduced under high WHSV because the contact time
between the feedstock and catalyst decreased. The
yield of ethene plus propene of ethylbenzene increased
–1
slightly, reaching 20.8 wt % at 6.79 h . This showed
that with increased WHSV, the ethylbenzene cracking
ability to light olefins was improved, although the
improvement was not obvious. Compared with the
other model compounds, the ethylbenzene cracking
ability to light olefins was bad. The rank order of the
yield of ethene plus propene of the different model
compounds was: 1-hexene > n-octane > ethylcyclo-
hexane > i-octane. It was consistent with the rank
order of the yield of ethene plus propene of different
model compounds at different reaction temperatures.
20
10
4.0 4.5 5.0 5.5 6.0 6.5 7.0 7.5
–1
WHSV, h
Fig. 6. Effect of WHSV on the yield of ethene plus propene
(reaction temperature, 660°C; S/O ratio, 0.36).
PETROLEUM CHEMISTRY Vol. 57 No. 3 2017

2
14
LIU et al.
(
3) With increased WHSV, the yield of ethene plus 15. N. Rahimi and R. Karimzadeh, Appl. Catal. A: Gen
3
98, 1 (2011).
propene of 1-hexene, n-octane, i-octane and ethylcy-
clohexane decreased continuously, and that of ethyl- 16. J. K. Reddy, K. Motokura, T. Koyama, A. Miyaji, and
T. Baba, J. Catal. 289, 53 (2012).
benzene increased slightly.
1
7. H. E. van der Bij, F. Meirer, S. Kalirai, J. Wang, and
(4) 1-Hexene exhibited good cracking perfor-
B. M. Weckhuysen, Chem. Eur. J. 20, 16922 (2014).
mance, followed by n-octane and ethylcyclohexane;
i-octane and ethylbenzene exhibited poor cracking
performance.
1
8. Y. T. Meng, H. C. Genuino, C. H. Kuo, H. Huang,
S. Y. Chen, L. C. Zhang, A. Rossi, and S. L. Suib,
J. Am. Chem. Soc. 135, 8594 (2013).
1
9. X. X. Chen, W. F. Yan, X. J. Cao, J. H. Yu, and
R. R. Xu, Microporous Mesoporous Mater. 119, 217
ACKNOWLEDGMENTS
(
2009).
Financial support was provided by the National
Basic Research Program of China (973 Program,
no. 2012CB215001), and the Program for New Cen-
tury Excellent Talents in the University of China
20. R. Cai, Y. Liu, S. Gu, and Y. S. Yan, J. Am. Chem. Soc.
1
32, 12776 (2010).
21. P. S. Wheatley, P. K. Allan, S. J. Teat, S. E. Ashbrook,
and R. E. Morris, Chem. Sci. 1, 483 (2010).
(
no. NCET–12–0970).
2
2. L. M. Ren, Q. M. Wu, C. G. Yang, L. F. Zhu, C. J. Li,
P. L. Zhang, H. Y. Zhang, X. J. Meng, and F. S. Xiao,
J. Am. Chem. Soc. 134, 15173 (2012).
References
. S. M. Sadrameli, Fuel 140, 102 (2015).
23. X. F. Li, B. J. Shen, and C. M. Xu, Appl. Catal. A: Gen
1
3
75, 222 (2010).
2
3
4
5
6
7
8
. M. A. B. Siddiqui, A. M. Aitani, M. R. Saeed, N. Al- 24. W. K. Liu, X. H. Meng, X. Zhao, G. Wang, J. S. Gao,
Yassir, S. and Al-Khattaf, Fuel 90, 459 (2011).
and C. M. Xu, Energy Fuels 23, 5760 (2009).
. L. X. Wang, K. Ozawa, T. Komatsu, and T. Ikeda, Appl. 25. X. H. Meng, C. M. Xu, and J. S. Gao, Energy Fuels 25,
Catal. A: Gen 407, 127 (2011).
1357 (2011).
. K. Keyvanloo, M. Sedighi, and J. Towfighi, Chem. 26. X. H. Meng, C. M. Xu, J. S. Gao, and L. Li, Appl.
Eng. J. 209, 255 (2012).
Catal. A: Gen 294, 168 (2005).
. N. Rahimi, R. Karimzadeh, S. M. Jazayeri, and 27. X. H. Meng, C. M. Xu, J. S. Gao, and L. Li, Appl.
K. D. Nia, Chem. Eng. J. 238, 210 (2014).
. L. D. Tian, J. M. Wang, B. X. Shen, and J. C. Liu,
Energy Fuels 24, 4380 (2010).
. C. Boyadjian, L. Lefferts, and K. Seshan, Appl. Catal.
A: Gen 372, 167 (2010).
Catal. A: Gen 301, 32 (2006).
2
8. X. H. Meng, C. M. Xu, J. S. Gao, and Z. C. Liu, Fuel
87, 2463 (2008).
2
9. O. Muraza, I. A. Bakare, T. Tago, H. Konno, T. Tani-
guchi, A. M. Al-Amer, Z. H. Yamani, Y. Nakasaka, and
T. Masuda, Fuel 135, 105 (2014).
. H. Konno, R. Ohnaka, J. Nishimura, T. Tago, Y. Naka-
3
0. Y. Nakasaka, T. Okamura, H. Konno, T. Tago, and
saka, and T. Masuda, Catal. Sci. Technol. 4, 4265
T. Masuda, Microporous Mesoporous Mater. 182, 244
(2014).
(2013).
9. D. C. Longstaff, Energy Fuels 26, 801 (2012).
3
1. A. Corma, J. Mengual, and P. J. Miguel, Appl. Catal.
1
0. K. Keyvanloo, A. Mohamadalizadeh, and J. Towfighi,
Appl. Catal. A: Gen 417, 53 (2012).
1. M. Sedighi, K. Keyvanloo, and J. Towfighi, Fuel 109,
32 (2013).
A: Gen 417, 220 (2012).
3
2. H. Konno, T. Tago, Y. Nakasaka, R. Ohnaka,
J. Nishimura, and T. Masuda, Microporous Meso-
porous Mater. 175, 25 (2013).
1
4
12. S. Inagaki, S. Shinoda, Y. Kaneko, K. Takechi,
3
3. Q. Zhang, S. Hu, L. L. Zhang, Z. J, Wu. Y. J. Gong,
R. Komatsu, Y. Tsuboi, H. Yamazaki, J. N. Kondo, and
Y. Kubota, ACS Catal. 3, 74 (2013).
and T. Dou, Green Chem. 16, 77 (2014).
3
4. S. L. Zhang, Y. J. Gong, L. L. Zhang, Y. S. Liu, T. Dou,
J. Xu, and F. Deng, Fuel Process. Technol. 129, 130
(2015).
1
3. J. Liu, G. Y. Jiang, Y. Liu, J. C. Di, Y. J. Wang, Z. Zhao,
Q. Y. Sun, C. M. Xu, J. S. Gao, A. J. Duan, J. Liu, Y. C.
Wei, Y. Zhao, and L. Jiang, Sci. Rep. 4, 1 (2014).
3
5. A. A. Al-Shammari, S. A. Ali, N. Al-Yassir, A. M. Aita-
ni, K. E. Ogunronbi, K. A. Al-Majnouni, and S. S. Al-
Khattaf, Fuel Process. Technol. 122, 12 (2014).
14. X. H. Meng, C. M. Xu, L. Li, and J. S. Gao, Energy
Fuels 24, 6233 (2010).
PETROLEUM CHEMISTRY
Vol. 57
No. 3
2017