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Title

Performance of compact fast pyrolysis reactor
with Auger‑type modules for the continuous liquidbiofuel production

Author(s)Nishimura, Shun; Ebitani, Kohki

Citation

AIP Conference Proceedings, 1929(1): 020008‑1‑
020008‑9Issue Date

2018‑01‑22

Type

Conference Paper

Text version

publisher

URL

http://hdl.handle.net/10119/15746

RightsCopyright 2018 Authors. Published by AIP
Publishing. Shun Nishimura, Kohki Ebitani, AIP
Conference Proceedings, 1929(1), 020008 (2018)
and may be found at
http://dx.doi.org/10.1063/1.5021921

Description

Japan Advanced Institute of Science and Technology

Performance of compact fast pyrolysis reactor with Augertype modules for the continuous liquid biofuel production
Shun Nishimura1),* and Kohki Ebitani1)

1
Graduate School of Advanced Science and Technology,
Japan Advanced Institute of Science and Technology (JAIST), 1-1 Asahidai, Nomi, Ishikawa 923-1292, Japan*

Corresponding author: s_nishim@jaist.ac.jp

Abstract. Development of a compact fast pyrolysis reactor constructed using Auger-type technology to afford liquidbiofuel with high yield has been an interesting concept in support of local production for local consumption. To establish
a widely useable module package, details of the performance of the developing compact module reactor were
investigated. This study surveyed the properties of as-produced pyrolysis oil as a function of operation time, and clarified
the recent performance of the developing compact fast pyrolysis reactor. Results show that after condensation in the
scrubber collector, e.g. approx. 10 h for a 25 kg/h feedstock rate, static performance of pyrolysis oil with approximately
20 MJ/kg (4.8 kcal/g) calorific values were constantly obtained after an additional 14 h. The feeding speed of cedar chips
strongly influenced the time for oil condensation process: i.e. 1.6 times higher feeding speed decreased the condensation
period by half (approx. 5 h in the case of 40 kg/h). Increasing the reactor throughput capacity is an important goal for the
next stage in the development of a compact fast pyrolysis reactor with Auger-type modules.
Keywords: Fast pyrolysis reactor, Auger-type module, Pyrolysis oil, Time-course performance

INTRODUCTION
Biomass utilization is expected to exert strong effects on the development of a sustainable society because
related processes are based on reproducible resources and low impact for CO2 emissions with a carbon neutral
concept. Therefore, not only academic but also industrial researchers skilled in biology, catalysis, theoreticalsimulation, agriculture, and mechanical engineering have been pursuing highly efficient technologies for converting
various biomass resources into valuable chemicals and fuels [1–6].
Fast pyrolysis of biomass resources is a unique methodology with high processing power in terms of biomasstransformation. It affords three important biomass-derived materials: syngas (gas phase), pyrolysis oil (liquid phase),and biochar (solid phase) [7–9]. Among the developed reactors of various types, the fast pyrolysis reactor with
Auger-type module(s) can support compact and high liquid yield processes effectively. As-produced pyrolysis oiland biochar are physically and chemically similar to materials obtained from conventional fast pyrolysis methods [9].
Because of this outstanding benefit of the Auger-type module, our project team has attempted to develop a newcompact fast pyrolysis reactor for continuous liquid biofuel production [10]. We considered that such a compact andmovable (in some cases) reactor can function in hilly and mountainous areas and wood treating companies to afford
liquid biofuels that can be used to produce energy in rural areas. Such local production for local consumption in

The Irago Conference 2017
AIP Conf. Proc. 1929, 020008-1–020008-9; https://doi.org/10.1063/1.5021921
Published by AIP Publishing. 978-0-7354-1621-5/$30.00

020008-1

Japan can provide benefits of reducing energy for transportation and can support environmentally friendly lifestyles
for human society.
This report presents discussion of the recent performance of the developed compact fast pyrolysis reactor in our
project based on the properties of as-produced pyrolysis oil as a function of operation time. We consider that thisAuger-type modules reactor would be used at near places from such as a timber mill company and a pellet plant,
serving a large quantity of woody biomass feedstock, constantly, as by-product.

EXPERIMENTAL
Figures 1 presents an overview of the flow system and development of a fast pyrolysis reactor with Auger-type
modules. Japanese cedar chips without bark parts (Iwaki, Fukushima, Japan) were used as the biomass feedstock
after drying (2–3 nm, <10 wt% H2O). The feeding rate was 25 kg/h in the main experimental condition (in somecases, 40 kg/h was also examined). Iron shots (SB-20; 1.4–1.7 mm) heated at 450–450°C were circulated as heat
carriers by the conjugated two screw lines in the reactor system. The horizontal Auger-screw proceeded thepyrolysis reaction, and the sloped Auger-screw carried the Iron shots to the heater head for reheating. The fine char
was first collected by a cyclone separator; then pyrolysis oil was condensed at a scrubber system. The off-gas was
not trapped at this time. In the initial system condition, pure water was set into the scrubber as a good condensing
agent for pyrolysis oil. Figure 2 shows that the water in the scrubber collector was concentrated gradually by
producing pyrolysis oil and obtaining a dark color as a function of time during 24 h operation at a 25 kg/h feeding
rate.

Screw

Gas&OilIron shots
as heat carriers

HeatingenergyCycloneseparator

Wood chips
Products
Char

Screw
Pyrolysis zone

(a)

(b)

FIGURE 1. Developed fast pyrolysis reactor with Auger-type modules (a) overview and (b) schismatic flow system.

(a)

(b)

FIGURE 2. Time-course of photography of the as-produced pyrolysis oil in the scrubber collector at 25 kg/h feeding rate:(a) 2 h, 4 h, 6 h, 8 h, 10 h, and 12 h, and (b) 14 h, 16 h, 18 h, 20 h, 22 h, and 24 h (from left side to right side).

020008-2

Performance of the developed compact fast pyrolysis reactor was elucidated from pyrolysis oil properties
characterized using various analytical techniques [10–12]. Elemental analysis for carbon (c), hydrogen (H), nitrogen(N), and sulfur (S) contents was conducted using an elemental analyzer (Vario EL3; Elementar AnalysensystemeGmbH). Sulfanilic acid (Merck Millipore; C: 41.61, H: 4.07, N: 8.09, S: 18.50 wt%) was used as standard forcalibrating the TCD detector. The sample oil (ca. 5–10 mg) was packed with a Tin (Sn) circular cylinder tube underO2 flow (99.5%, >100 ml/min), and was introduced into the furnace at 1150°C under O2/He flow, which wasconnected directly to a reduction tube at 850°C. The oxygen (O) value was estimated from the differences in C, H,
N, and S values.
Water (H2O) contents were measured using Karl Fischer (KF) titration methodology with a volumetric titration
analyzer (MKA-610; Kyoto Electronics Mfg. Co. Ltd.). After the sample oil (ca. 0.05–0.10 g) was dispersed into
HYDRANAL-KetoSolver (Fluka Chemika GmbH), it was neutralized using HYDRANAL-Composite 5K (Fluka
Chemika GmbH) agent, of which the activity value was calibrated using pure water before analysis. Three indexesof ash, weight density, and pour point values were estimated, respectively, using Japanese Industrial Standard (JIS)methods K 2272, 2269, and 2249.
The higher heating value (HHV) was obtained using a calorimeter (C200; IKA). The sample oil (ca. 0.5 g) was
put into a gelatin capsule (18759 J/g) with an appropriate amount of paraffin chips (46619 J/g) as a combustion
enhancer. Then it was sealed in the special vessel with O2 pressurized to 30 bar. Ignition was done using electronic
power (100 J) through cotton yarn (50 J/twist). The lower heating value (LHV) was calculated using H2O content
with a water condensation heat value (40.8 kJ/mol).
A gas chromatograph (7890B; Agilent Technologies Inc.) with a time-of-flight mass spectrometer (GC-TOFMS,
AccuTOFTM GCx; JEOL) was used to ascertain the mixed components. A DB-1 capillary column (30 m × 0.32 mm
× 0.25 µm; Agilent Technologies Inc.) was used for separation. After the sample of pyrolysis oil (100 mg) was
dispersed in methanol (1 mL), 1.00 µL of the mixture was injected with a split ratio = 10.0 using an auto injector(7683B; Agilent Technologies Inc.). The column oven was kept at 50°C for 3 min; then it was heated from 50°C to
320°C with 5°C/min rate. Mass spectrometry presented results in the range of m/z = 35.00–800.00 during a 3.20–
60.00 min GC program, after tuning at around m/z = 264 with perfluorotributylamine (PFTBA; Wako Pure
Chemical Inds. Ltd.).
Fourier transform ion cyclotron resonance mass spectrometry (FT-ICRMS) was conducted using a device(SolariX; Bruker Daltonics Inc.) attached with a 9.4 T superconducting magnet. The pyrolysis oil was diluted as 1
µL/mL concentration with ethanol; then it was introduced/ionized using electrospray ionization (ESI) at 4.5 kV(negative-ion mode). Oleic acid (C18H33O2; 281.24860 Da (monoisotopic) was used as an internal standard for m/z
adjustment. A 2 M (megabyte) dataset (3.84 M points) was acquired for m/z = 100–1200. Five scans of FT-ICR
datasets were added to enhance the S/N ratio. From the obtained negative-ion FT-ICRMS spectrum, the estimatedcomposition formulas determined by the actual m/z value below ±1.0 ppm error were listed as the expectedcompounds (CαHβOχNδ) in the sample. The C, O, and C-O contribution diagrams in the as-prepared pyrolysis oil
were described by the count of the expected formula with the target element number: C number (α) and/or O
number (χ).

RESULTS AND DISCUSSION
Figures 3 presents the time-course of physical properties of as-produced pyrolysis oil in the scrubber collector
on C and O element contents, water content, and HHV at 25 kg/h feeding rate. The C values gradually increased
concomitantly with decreasing O values as a function of time at the beginning of operation for 10 h. Thereafter,these gave approximately constant values of C: 50 wt% and O: 40 wt%. The water contents also gave a similartendency to afford approx. 15 wt% at 10–24 h operation. The as-produced pyrolysis oil showed higher C content andlower H2O content conditions. Therefore, the HHV also served the same alterations.
Accordingly, it was expected that condensation of pyrolysis oil into the initial condensing agent (water) was
progressing linearly as a function of the operation time within 10 h operation at a feeding rate of 25 kg/h; then thestatic state for pyrolysis oil generation with constant quality was achieved for additional operation time. It isnoteworthy that when we increased the feeding rate to 40 kg/h, such condensation was concluded within 5 h as well(data not shown).

020008-3

100
C
O

80

25

80

Water content (wt%)

Element content (wt%)

90

Higher heating value (MJ/kg)

100

70
60
50
40
30
20

60

40

20

20

15

10

5

10
0

0
0

5

10
15
20
Operation time (h)

25

(a)

0
0

5

10
15
20
Operation time (h)

25

0

5

10
15
20
Operation time (h)

(b)

25

(c)

FIGURE 3. Time-course of the physical properties of as-produced pyrolysis oil in the scrubber collector at a 25 kg/h feeding
rate: (a) C and O element contents, (b) water content, and (c) HHV.

Figure 4(a) shows GC charts obtained from GC-TOFMS analysis. Peak intensities showed a gradual increaseduring initial 10 h operation, and would be similar after 10 h. It is noteworthy that no significant differences were
found in the peak patterns in GC-charts during 24 h operation.

Furans, Small alkanes

Methoxy, Hydroxy Aromatics

O

OH

Terpene
OH

(a)

(b)

FIGURE 4. (a) Time-course of GCTOF-MS chart of the as-produced pyrolysis oil in the scrubber collectorand (b) expected structure of major compounds confirmed using MS at a 25 kg/h feeding rate.

Expected structures of major compounds confirmed by MS analysis are shown in Figure 4(b). Furans and theirderivatives such as 2-furaldehyde, 2(5H)-furanone, pentanal, and hydroxyacetone were observed at a shorter
retention time (<17 min). A variety of methoxy and hydroxyl aromatic compounds often appeared at widely diverse
retention times (15–35 min). Polycyclic compounds, especially terpene-like compounds, were detected at longer

020008-4

retention times (>45 min). In general, the wood composition was regarded as including the following contents:
cellulose (50–50%), hemicellulose (20–40%), lignin (18–35%), and others (1–4%) [13]. Therefore, pyrolysis ofsaccharides would generate such furans and its derivatives, whereas pyrolysis of lignin produced methoxy andhydroxyl aromatic compounds included in pyrolysis oil. An important concern is that terpene-like polycyclic
compounds are attributable to fine biochar that is not removed by cyclone systems.
Acetic acid was also included in pyrolysis oil in large quantities as described in our earlier reports [10–12].
However, it was not detected in the GCTOF-MS study because the short retention time (<5 min) was cut off toprotect the MS filament.
Table 1 presents details of the physical properties of as-produced pyrolysis oil at 12 h and 24 h operations at a
25 kg/h feeding rate. Physical properties were comparable with the typical properties of wood pyrolysis oil [7]except for ash index which served a little higher value in our module reactor (vide infra). As expected from thediscussion presented above, almost all values and properties showed similar trends for these two pyrolysis oils. Asprepared pyrolysis oil possessed a calorimetric value of approx. 20 MJ/kg, which was apparently almost half thevalue of conventional fuel oils such as gasoline, light diesel oil, and heavy fuel oil (42–45 MJ/kg). Many efforts
have been undertaken to overcome the issue of a low HHV value of pyrolysis oil through dehydrogenation ofpyrolysis oil to remove oxygen using a metal-supported catalyst under a pressurized hydrogen condition [12, 14–16].
However, including such an upgraded construction would be difficult in our Auger-type module system because of
the concerns about hydrogen usage in rural mountain areas.

TABLE 1. Physical properties of as-generated pyrolysis oil condensed in the scrubber collector at a 25 kg/h feeding rate
Index

12 h

C
H
N
S
O
H2O
Ash
Pour point
Weight density
Higher heating value(HHV)
Lower heating values
(LHV)

24 h

52.4 wt%
6.9 wt%
0.3 wt%<0.1 wt%[a]40.4 wt%
15.3 wt%
0.364 wt%
-10.0°C>1.180[a]21.0 MJ/kg(5.0 kcal/g)
19.6 MJ/kg(4.7 kcal/g)

48.6 wt%
6.1 wt%
1.2 wt%0 wt%
44.1 wt%
17.8 wt%
0.339 wt%
-10.0°C>1.180[a]20.3 MJ/kg(4.8 kcal/g)
19.0 MJ/kg(4.5 kcal/g)[a] Limit of detection

For details of properties of petroleum-based and biomass-based fuels, FTICR-MS analysis has been a versatile
discussion tool [10–12, 17–20]. Therefore, we used FT-ICRMS analysis to compare differences between 12 h and
24 h operation pyrolysis oils further. Figure 5 depicts the negative-ion FT-ICRMS broadband spectra of as-preparedpyrolysis oils. Both broadband spectra served a variety of peaks below m/z < 730. According to exact massestimation analyses, 1836 and 1974 compounds with CαHβ OχNδ formula were ascertained, respectively, for 12 h and
24 h. The quantity of each compound could not be ascertained using this analytical technique: discussion of thequantity of each compound was difficult given the intensity of the broad spectrum.

020008-5

(a)

(b)

FIGURE 5. Negative-ion FT-ICRMS broadband spectrum of as-prepared pyrolysis oil obtained at(a) 12 h and (b) 24 h operation in the range of m/z = 100–1200.

Figures 6 and 7 respectively show the C number (α) or O number (χ) distribution and the C–O number (α-χ)
correlation distributions in pyrolysis oils obtained at 12 h and 24 h operation. These were drawn based on theassigned CαHβOχNδ formulas by FT-ICRMS analysis. Results show that pyrolysis oil was constructed mainly from
5-45 carbons and 2–20 oxygen compounds. A slight difference was found between 12 h and 24 h operation pyrolysis
oils determined from the 1D distributions shown in Figure 6. Detailed investigations particularly addressing 2D
correlation distributions between C and O shown in Figures 7 revealed only a slight difference especially in higher
C and O number correlation areas (C: 30–40 and O: 15–20). The meaning of such a change remains unclear. It is the
subject of ongoing work.

10

6
12 h
24 h

12 h
24 h
8
Frequency (count%)Frequency (count%)

5
4
3
2

6

4

2

1

0

0
0

10

20
30
40
Carbon number in the expected compound (α)

0

50

5

10

15

20

25

Oxygen number in the expected compound (χ)

(a)

(b)

FIGURE 6. Results of FT-ICRMS analysis for (a) carbon number (α) or (b) oxygen number (χ) distribution of
12 h and 24 h operation pyrolysis oils.

020008-6

(a)

(b)

FIGURE 7. Results of FT-ICRMS analysis for carbon-oxygen (α -χ) number correlation distributions of(a) 12 h and (b) 24 h operation pyrolysis oils.

The impurities included in the pyrolysis oil are tentatively discussed to provide information about the pyrolysis
oil generated by our Auger-type module reactor. Two important expectations were obtained from ash color
observation and extraction experiment.
After the ash value test results presented in Table 1, we obtained orange powder as shown in Figure 8(a). In
general, non-combustible minerals such as Na2O, K2O, CaO, MgO, SiO2, Al2O3, Fe2O3 (reddish-orange color),MnO (black color), P2O5, TiO2, SO3, and K2CO3 are anticipated as candidates for biomass-derived ash compounds.
Iron shots were used as heat carriers in our Auger-type module reactor. These would be ground in the reactor
eventually by mutual collision. Furthermore, the coarse-grained Fe2O3 (reddish-orange color) would affect the ash
in the pyrolysis oil.
In an additional experiment, to identify the presence of solid impurities in pyrolysis oil, approx. 5 g of pyrolysis
oil was “washed” using methanol (40 mL) five times: decantation and centrifugation with MeOH solvent wereapplied to the pyrolysis oil. After drying the residues under vacuum at room temperature (approx. 25°C), more than
1.19 wt% of black powder was collected (Figure 8(b)). Apparently, some biochar remained in the pyrolysis oil.

(a)

(b)

FIGURE 8. Photographs of (a) ash and (b) remaining powder after MeOH decantation in pyrolysis oil generated during 24 hoperation.

020008-7

CONCLUSIONSThe performance of our developed compact fast pyrolysis reactor with Auger-type modules for continuous liquidbiofuel production is discussed based on the properties of as-produced pyrolysis oil as a function of the operation
time. A 25 kg/h feeding rate of Japanese cedar chips required 10 h at the beginning of operation for condensation
processes to afford high-quality pyrolysis oil in our Auger-type module system. This process term can be diminishedto <5 h by increasing the feeding rate to 40 kg/h. These observations suggest that improvement of throughput ability
is a crucially important factor for future development. After condensation, pyrolysis oil possessing approx. 20 MJ/kg
HHV would be generated constantly. These operation performance results were supported by data from GC-TOFMS
and FT-ICRMS analyses. Some impurities such as Fe2O3 and fine biochar powder were detected in pyrolysis oil.
However, these were non-toxic and would not inhibit pyrolysis oil combustion.

ACKNOWLEDGMENTS
This research was conducted (in part) as a collaborative work with Toonokousan Co. (Iwaki, Fukushima, Japan)
under financial support by National Agriculture and Food Research Organization (NARO), Japan. The authors
appreciate Dr. A. Miyazato (Nanocenter, JAIST, Japan) and Dr. S. Hosokai (Advanced Industrial Science andTechnology: AIST, Japan), respectively, for their valuable support on FT-ICRMS measurement and technical advice
for machine modifications. Measurements of ash, weight density, and pour point values were taken by Yamato
Kankyo Co. (Kawakita, Ishikawa, Japan).

REFERENCES
1.
2.
3.
4.
5.
6.

7.
8.
9.
10.

11.
12.
13.
14.
15.

Chemicals and Fuels from Bio-Based Building Blocks, edited by F. Cavani, S. Albonetti, F. Basile and A.
Gandini (Wiley-VCH, Weinheim, Germany 2016).
F. H. Isikgor and C. R. Becer, Polym. Chem. 6, 4497–4559 (2015).
X. Cao, S. Sun, and R. Sun, RSC Adv. 7, 48793–48805 (2017).
H. Kobayashi and A. Fukuoka, Bull. Chem. Soc. Jpn., in press (DOI: 10.1246/bcsj.20170263).
S. Nishimura and K. Ebitani, J. Jpn. Petrol. Inst. 60, 72–84 (2017).
S. Nishimura and K. Ebitani, “Catalytic Conversions of Biomass-derived Furaldehydes towards Biofuels,” inGreen Chemical Processing and Synthesis, edited by I. Karame and H. Srour (InTechOpen, Rijeka, Croatia,
2017), pp.51–68.
D. Mohan, C. U. Pittman, Jr., and P. H. Steele, Energy Fuel 20, 848–889 (2006).
A. V. Bridgewater and G. V. C. Peacock, Renew. Sust. Energy Rev. 4, 1–73 (2000).
J. N. Brown, “Development of a lab-scale auger reactor for biomass fast pyrolysis and process optimization
using response surface methodology,” Master thesis, Iowa State University, 2009.
S. Nishimura, A. Miyazato, and K. Ebitani, “Properties of bio-oil generated by pyrolysis of forest cedar
residuals with the movable Auger-type reactor” in The Irago Conference 2015, AIP Conf. Proc. 1709, editedby A. Sandhu and H. Okada (American Institute of Physics, Melville, NY, 2016) pp. 020026.
S. Nishimura, Enerugii Gakkai Kikanshi /Enermix 96, 474–481 (2017).
N. Koike, S. Hosokai, A. Takagaki, S. Nishimura, R. Kikuchi, K. Ebitani, Y. Suzuki, and S. T. Oyama, J.
Catal. 333, 115–126 (2016).
N. Sun, H. Rodriguez, M. Rahman, and R. D. Rogers, Chem. Commun. 47, 1405–1421 (2011).
J. Wildschut, F. H. Mahfud, R. H. Venderbosch, and H. J. Heeres, Ind. Eng. Chem. Res. 48, 10324–13334(2009).
A. Takagaki, Enerugii Gakkai Kikanshi /Enermix 96, 468–473 (2017).

020008-8

16. A. N. K. Lup, F. Abnisa, W. M. A. W. Daud, and M. K. Aroua, J. Ind. Eng. Chem. 56, 1–34 (2017).
17. K. Miyabayashi, Y. Naito, M. Yamada, M. Miyake, M. Ushio, J. Fuchigami, R. Kuroda, T. Ida, K. Hayashida
and H. Ishihara, Fuel Process. Technol. 89, 397–405 (2008).
18. K. Miyabayashi, Y. Naito and M. Miyake, J. Jpn. Petrol. Inst. 52, 159–171 (2009).
19. Y. Liu, Q. Shi, Y. Zhang, Y. He, K. H. Chung, S. Zhao and C. Xu, Energy Fuel 26, 4532–4539 (2012).
20. I. Leonardis, S. Chiaberge, T. Fiorani, S. Spera, E. Battistel, A. Bosetti, P. Cesti, S. Reale and F. D. Angelis,
ChemSusChem 6, 160–167 (2013).

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