Catalytic pyrolysis of Pinus densiflora over mesoporous Al2O3 catalysts

Article abstract of DOI:10.1166/jnn.2018.15653

The thermal and catalytic pyrolysis of Pinus densiflora (P. densiflora) were performed to test the catalytic cracking efficiency of two mesoporous Al₂O₃ catalysts with different surface areas. Thermogravimetric analysis (TGA) of P. densiflora showed that the differential TG (DTG) peak heights obtained from catalytic pyrolysis were smaller than those of non-catalytic pyrolysis due to the conversion of the reaction intermediates to coke. Pyrolyzer-gas chromatography/mass spectrometry analysis/flame ionization detection (Py-GC/MS/FID) suggested that using the Al₂O₃ catalysts, the yields of phenols and levoglucosan decreased with a concomitant increase in the yields of aldehydes, alcohol, ketones, and furans. Between the two catalysts, Al₂O₃-B prepared by spray pyrolysis showed higher cracking efficiency than Al₂O₃-A prepared by hydrothermal method because of its larger surface area.

Full text of DOI:10.1166/jnn.2018.15653

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Catalytic Pyrolysis of Pinus densiflora Over
Mesoporous Al2O3 Catalysts
Young-Min Kim1ꢀ†, Gwang Hoon Rhee2ꢀ†, Chang Hyun Ko3ꢀ†, Ki Hoon Kim4ꢀ†, Kyeong Youl Jung5,
Ji Man Kim6, and Young-Kwon Park4ꢀ∗
1Department of Environmental Sciences and Biotechnology, Hallym University, Chuncheon 24252, Korea
2Department of Mechanical and Information Engineering, University of Seoul, Seoul 02504, Korea
3School of Chemical Engineering, Chonnam National University, Gwangju, 61186, Korea
4School of Environmental Engineering, University of Seoul, Seoul 02504, Korea
5Department of Chemical Engineering, Kongju National University, Cheonan 31080, Korea
6Department of Chemistry, Sungkyunkwan University, Suwon 16419, Korea
The thermal and catalytic pyrolysis of Pinus densiflora (P. densiflora) were performed to test the
catalytic cracking efficiency of two mesoporous Al2O3 catalysts with different surface areas. Ther-
mogravimetric analysis (TGA) of P. densiflora showed that the differential TG (DTG) peak heights
obtained from catalytic pyrolysis were smaller than those of non-catalytic pyrolysis due to the con-
version of the reaction intermediates to coke. Pyrolyzer-gas chromatography/mass spectrometry
analysis/flame ionization detection (Py-GC/MS/FID) suggested that using the Al2O3 catalysts, the
IP: 182.53.181.212 On: Sun, 17 Jun 2018 14:23:24
yields of phenols and levoglucosan decreased with a concomitant increase in the yields of aldehy-
Copyright: American Scientific Publishers
des, alcohol, ketones, and furans. Between the two catalysts, Al2O3-B prepared by spray pyrolysis
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showed higher cracking efficiency than Al2O3-A prepared by hydrothermal method because of its
larger surface area.
Keywords: Pinus densiflora, Mesoporous Al2O3, Catalytic Pyrolysis.
1. INTRODUCTION
effective on catalytic pyrolysis because the pyrolysis prod-
ucts of biomass contain considerable amounts of large
molecular compounds.21ꢀ22
In this study, the catalytic pyrolysis of Pinus densiflora
(P. densiflora) over two types of mesoporous catalyst with
different properties was investigated by thermogravimetric
analysis (TGA) and pyrolyzer-gas chromatography/mass
spectrometry/flame ionization detector (Py-GC/MS/FID).
Owing to the decreased energy source and climate change
due to global warming, the development of renewable
energy has become an important worldwide research area.
Biomass is a candidate renewable energy source that can
produce gas, liquid, and solid products via proper ther-
mal conversion technologies.1–17 Pyrolysis is an appropriate
method for producing large quantities of bio-oil from many
kinds of biomass. On the other hand, the use of bio-oil
obtained from the pyrolysis of biomass is limited by its low
quality with high acidity, corrosiveness, water content, and
oxygen content.2ꢀ5ꢀ6 To overcome the limitations of bio-oil,
catalytic pyrolysis has been studied extensively and many
kinds of catalysts, such as zeolites and metal catalysts, have
been applied.18–21 Al2O3 is a low-cost catalyst with poten-
tial use for the catalytic pyrolysis of biomass. Nevertheless,
its low catalytic efficiency is considered a problem.
One of the possible ways to increase the catalytic
activity is to increase the pore size, which can be very
2. EXPERIMENTAL DETAILS
2.1. Samples
P. densiflora, obtained from the National Institute of Forest
Science in Korea, was cryo-milled using a ball milling
device with liquid nitrogen, dried at 80 ꢀC for 4 hours, and
sieved to make a size between 75 and 200 ꢁm.
2.2. Catalysts
Two types of mesoporous alumina were synthesized
using the procedures reported elsewhere.23ꢀ24 Meso-
porous alumina-A (Al2O3-A) was synthesized by stirring
a mixture solution of cetyltrimethylammoniumbromide
∗Author to whom correspondence should be addressed.
†Co-first authors.
6300
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doi:10.1166/jnn.2018.15653

Kim et al.
Catalytic Pyrolysis of Pinus densiflora Over Mesoporous Al2O3 Catalysts
ꢀ
(CTAB), distilled water, and ethanol at 60 C for 20 min.
Subsequently, an ammonia solution (30 wt.% NH3ꢂ and
aluminum tri-sec-butoxide were added and stirred at 60 ꢀC
for 3 hours. The precipitates after stirring were collected
using a vacuum filter and dried at 100 ꢀC for 24 h.
Al2O3-A was finally obtained by calcination of the precip-
itates at 600 ꢀC for 6 h. Mesoporous alumina-B (Al2O3-B)
was synthesized using a spray pyrolysis process. For this,
aluminum nitrate and CTAB (CTAB to aluminum molar
ratio: 0.3) were used. Spray pyrolysis process was carried
(177 m2/g). Both catalysts showed a type IV hysteresis
loop indicating the presence of mesopores. The wide-angle
XRD pattern of mesoporous Al2O3-A synthesized in this
study showed the three typical peaks of cubic ꢄ-Al2O3
(Fig. 1(a)). Al2O3-B (Fig. 1(b)) showed a broad diffrac-
tion peak, indicating that the alumina particles might have
disordered warm- or sponge-like mesostructures.23ꢀ24
3.2. TG Analysis
Figure 2 presents the differential TG (DTG) curves show-
ing the thermal and catalytic pyrolysis of P. densiflora over
Al2O3 catalysts at a heating rate of 20 ꢀC/min. The decom-
ꢀ
out at 700 C under an air flow of 20 L/min and calcined
ꢀ
at 550 C for 3 h.
ꢀ
The Brunauer, Emmett, and Teller (BET) surface areas
of the synthesized catalysts were characterized using a
Belsorp mini II (MicrotracBel, Japan) for nitrogen sorption
and the crystal structures were examined by wide angle
X-ray diffraction (XRD, Rigaku D-MAX 3) using Cu-Kꢃ
radiation at 40 kV and 40 mA.
position of P. densiflora started at approximately 200 C,
ꢀ
and then decomposed rapidly to 400 C. Although the
maximum decomposition temperatures (Tmax)s of the ther-
mal and catalytic pyrolysis of P. densiflora were similar,
their peak heights were quite different. Compared to non-
catalytic pyrolysis, catalytic pyrolysis showed lower peak
heights due to the formation of solid coke on the external
surface or in the pores of the catalysts.
2.3. TG Analysis
TGA (Pyris Diamond, Perkin Elmer) was used to deter-
mine the thermal properties of the thermal and catalytic
pyrolysis of P. densiflora. For this, 6 mg of P. densi-
ꢀ
flora was heated from ambient temperature to 600 C at
a heating rate of 20 ꢀC/min under flowing nitrogen at
140 mL/min. For catalytic pyrolysis, 6 mg of Al2O3 cata-
lyst was mixed together with P. densiflora.
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2.4. In-Situ Catalytic Pyrolysis
A multi-shot Py (EGA/PY-3030D, Frontier Laboratories
Ltd.)-GC/MS/FID (7890A/5975C inert, Agilent Technolo-
gies) was used to identify the products from the thermal
and catalytic pyrolysis of P. densiflora. P. densiflora (1 mg)
or a mixture of P. densiflora and catalyst (2 mg) in a SUS
sample cup was free-fallen into a pre-heated pyrolyzer
heater (400 ꢀC and 600 ꢀC). The chemicals emitted
from the pyrolyzer were transferred to a capillary column
(UA-5, 30 m × 0.25 mm × 0.25 ꢁm; Frontier Laborato-
ries Ltd.) via a GC split/splitless inlet and cyro-focused
(2 min) at the front part of the column using a MicroJet
cryo trap (MJT-1030E, Frontier Laboratories Ltd.). After
cyro-focusing, the chemicals were separated in a column
ꢀ
accordiꢀng to the GC oven program, froꢀm 40 C (5 min)
to 320 C (10 min) at a heating rate 20 C/min. Each MS
peak on the chromatograms was identified by the NIST
8th (National Institute of Standards and Technology, USA)
and/or F-search (F-search all in one, Frontier Laboratories
Ltd.) libraries. Py-GC/FID analysis was also conducted to
compare the amounts of the products by a comparison of
the peak area of each chemical.
3. RESULTS AND DISCUSSION
3.1. Characterization of Mesoporous Al2O3 Catalysts
The results of N2-sorption indicated that the surface area of
Al2O3-B (260 m2/g) was much larger than that of Al2O3-A
Figure 1. XRD patterns of mesoporous alumina (a)Al2 O3-A,
(b) Al2O3-B.
J. Nanosci. Nanotechnol. 18, 6300–6303, 2018
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Catalytic Pyrolysis of Pinus densiflora Over Mesoporous Al2O3 Catalysts
Kim et al.
Figure 2. DTG curves obtained from thermal and catalytic TG analysis
of P. densiflora over different mesoporous Al2O3 catalysts.
(a) 400 ºC
3.3. Pyrolysis of P. densiflora
Figure 3 shows the absolute peak areas for each chemical
group obtained from the non-catalytic pyrolysis of P. densi-
ꢀ
ꢀ
flora at 400 C and 600 C. As expected, the amounts
of oxygen-containing compounds were higher in the prod-
ucts obtained from pyrolysis at 400 and 600 ꢀC.25–27 Com-
pared to 400 ꢀC, large amounts of aldehydes, alcohols, and
phenols were obtained due to the increased cracking effi-
ciency and the additional decomposition of lignin at the
higher temperatures.28 The content of aromatics were also
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increased by non-catalytic pyrolysis at 600 C.
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3.4. In-Situ Catalytic Pyrolysis
Figure 4 shows the product distributions obtained from
the thermal and catalytic pyrolysis of P.ꢀ densiflora over
(b) 600 ºC
ꢀ
the Al2O3 catalysts at 400 C and 600 C, respectively.
Compared to non-catalytic pyrolysis, catalytic pyroly-
sis resulted in increased amounts of aldehydes, alcohol,
ketones, furans together with decreased quantities of phe-
nols and anhydrosugars due to the catalytic effect. Lee
et al.29 reported increased yields of furan and decreased
Figure 4. FID peak area distribution for the chemical groups obtained
from catalytic pyrolysis of P. densiflora over Al2O3 catalysts at (a) 400
and (b) 600 ꢀC.
yields of anhydrosugars, such as levoglucosan. Between
the two Al2O3 catalysts, Al2O3-B showed higher catalytic
activity with a further decrease in the quantities of phe-
nols and anhydrosugars produced. The aromatics were
also increased further using Al2O3-B. The higher catalytic
activity of Al2O3-B can be explained by its larger BET
surface area than Al2O3-A.
Table I lists the detail peak areas of the major prod-
ucts, which can be classified into aromatics, phenols and
anhydrosugars, obtained from the catalytic pyrolysis of
ꢀ
P. densiflora over both Al2O3 catalysts at 600 C. Com-
pared to non-catalytic pyrolysis, catalytic pyrolysis over
Al2O3-A produced smaller amounts of branched phenols
(cresols, guaiacols, eugenols, and vanillin) and levoglu-
cosan. The amounts of these branched phenols and lev-
oglucosan were decreased further using Al2O3-B together
with an increase in the mono-phenol yield, which also
Figure 3. FID peak area distribution for the chemical groups obtained
from the pyrolysis of P. densiflora at 400 and 600 ꢀC.
6302
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Kim et al.
Catalytic Pyrolysis of Pinus densiflora Over Mesoporous Al2O3 Catalysts
Table I. The detailed peak areas for phenolics and levoglusosan
obtained from the thermal and catalytic pyrolsysis of P. densiflora at
600 ꢀC. (Units: FID peak area ×10−6).
7. H. Kim, H. Shafaghat, J. Kim, B. S. Kang, J. K. Jeon, S. C.
Jung, I. G. Lee, and Y. K. Park, Korean J. Chem. Eng. (2018),
https://doi.org/10.1007/s11814-018-0002-3.
8. J. Fang, L. Zhan, Y. S. Oh, and B. Gao J. Ind. Eng. Chem. 57, 15
(2018).
Catalyst
No catalyst
Al2O3-A
Al2O3-B
9. J. Zhu, L. Gan, B. Li, and X. Yang, Korean J. Chem. Eng. 34, 110
(2017).
10. E. Mehrvarz, A. A. Ghoreyshi, and M. Jahanshahi, Korean J. Chem.
Eng. 34, 305 (2017).
11. D. Krishnaiah, C. G. Joseph, S. M. Anisuzzaman, W. M. A. W.
Daud, M. Sundang, and Y. C. Leow, Korean J. Chem. Eng. 34, 1377
(2017).
Phenol
Cresols
Guaiacols
Eugenols
Vanillin
16ꢅ3
18ꢅ8
93ꢅ0
62ꢅ0
34ꢅ0
157ꢅ7
20ꢅ9
16ꢅ6
82ꢅ6
56ꢅ5
33ꢅ8
123ꢅ3
25.2
17.9
73.5
34.6
12.6
19.8
Levoglucosan
12. J. S. Cha, S. H. Park, S. C. Jung, C. Ryu, J. K. Jeon, M. C. Shin,
and Y. K. Park, J. Ind. Eng. Chem. 40, 1 (2016).
13. M. W. Yap, N. M. Mubarak, J. N. Sahu, and E. C. Abdullah, J. Ind.
Eng. Chem. 45, 287 (2017).
14. H. Wang, W. Xia, and P. Lu, Korean J. Chem. Eng. 34, 1867
(2017).
indicates a much higher catalytic cracking efficiency of
Al2O3-B than Al2O3-A.
15. S. Wan, S. Wang, Y. Li, and B. Gao, J. Ind. Eng. Chem. 47, 246
(2017).
16. B. Wang, S. Liu, F. Li, and Z. Fan, Korean J. Chem. Eng. 34, 717
(2017).
17. H. N. Tran, S. J. You, and H. P. Chao, Korean J. Chem. Eng. 34, 1708
(2017).
18. Y. Lee, D. Oh, Y. M. Kim, J. Jae, S. C. Jung, J. K. Jeon, S. C. Kim,
and Y. K. Park, Appl. Surf. Sci. 429, 95 (2018).
19. H. W. Lee, Y. M. Kim, C. S. Jeong, S. H. Park, J. M. Kim, S. C.
Jung, S. C. Kim, J. K. Jeon, and Y. K. Park, Sci. Adv. Mater. 9, 934
(2017).
4. CONCLUSION
The non-catalytic pyrolysis of P. densiflora revealed a
higher cracking efficiency at a higher temperature. Com-
pared to non-catalytic pyrolysis, catalytic pyrolysis pro-
duced smaller amounts of aldehydes, alcohol, ketones, and
furans as well as lower levels of phenols and anhydrosug-
ars. Between two catalysts, Al2O3-B showed higher cat-
alytic cracking efficiency than Al2O3-A due to its larger
BET surface area.
20. H. W. Lee, H. Lee, J. S. Cha, J. K. Jeon, S. H. Park, S. C. Jung,
J. M. Kim, S. C. Kim, and Y. K. Park, Sci. Adv. Mater. 9, 1015
(2017).
Acknowledgment: This research was supported by
Basic Science Research Program through the National
Research Foundation of Korea (NRF) funded by the Min-
istry of Education (NRF-2016R1D1A1B03935954).
21. H. Kim, H. Lee, E. H. Lee, C. Ryoo, J. M. Kim, S. H. Park, S. C.
Jung, K. S. Yoo, and Y. K. Park, Sci. Adv. Mater. 9, 945 (2017).
22. S. O. Limarta, J. M. Ha, Y. K. Park, H. Lee, D. J. Suh, and J. Jae,
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Copyright: American Scientific Publishers
Delivered by Ingenta
J. Ind. Eng. Chem. 57, 45 (2018).
23. S. Bodoga, R. V. Sharma, A. K. Dalai, and J. Adjaye, Appl. Catal.
A-Gen. 489, 86 (2015).
24. J. H. Kim, K. Y. Jung, J. Y. Park, and S. B. Cho, Micropor. Mesopor.
Mat. 128, 85 (2010).
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Received: 23 September 2017. Accepted: 8 January 2018.
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