Effective use of energy from disease cedar of Sanbu region in Japan
S. Sakai1, C.Igarashi1,ZZ.Hlaing 1,2 ,M. Adachi1, Y.Yanagisawa1, S.Uchiyama 2and H. Nakagome1*
1 Graduate School of Engineering, Chiba University, 1-33, Yayoi, Inage, Chiba, 236-8522, Japan
2 National Institute of Public Health, 2-3-6 Minami, Wako city, Saitama, 351-0197, Japane-mail: nakagome@tu.chiba-u.ac.jp ; Tel +81-43-290-3466 & Fax ; +81-43-290-3466

Abstract
Originated cedar region called "Sanbu cedar" has been widely distributed in Sanbu City,Chiba Prefecture, Japan. In recentyears, the lack of forestry actors due to the aging and the downturn of timber value are became a problem that the diseasecedar more than 80% of the cedar forest. In this study, we investigated to improve the efficiency of gas production andanalysis of the products of health cedar and disease cedar by using steam gasification with or without sodium hydroxide at
700 ºC. Based on the experimental data, we are carried out estimation of the synthesis gas produced by the stream
gasification of diseases cedar. From these result, the recoverable amount is expected 57548.2GJ / year by disease cedar, it
is equivalent to 5.3% (heat utilization rate) total energy demand of the city. It is equivalent of 950 units of annual energy
consumption in the home of Sanbu city.

Keywords: Sanbu Cedar, Biomass, Stream gasification, Sodium hydroxide, Synthetic gas

1. Introduction
The woody biomass has a great abundance in Japan but
the energy applications are not used a large quantities.
The effective utilization of biomass energy will not go,
due to the high cost of forest biomass collection andtransportation, aging and delay of technologicaldevelopment. In recent years, there is a strong demand
for the promotion of the utilization of forest biomass
further, from the viewpoint of forestry revitalization andjob creation. In this study, we assumed that the gas
converted to energy by using thinned wood and diseases
wood of Sanbu region, Chiba prefecture, and used as a
new industry in the region, such as regional transport fuel.
Our purpose was "to reveal the experimental conditions
while reducing tar gasification is a challenge to efficiently
generate synthesis gas useful as fuel" and "to consider
the possibility of Sanbu cedar that utilization gas as a fuelin the future region." Therefore, we examined to improvethe efficiency of produced gas and, measurement andanalysis of the products of pyrolysis gasification
experiments of health and disease cedar. Based on theexperimental data, we are carried out estimation of thesynthesis gas produced by the stream gasification ofdiseases cedar.

2. Materials and Methods
The sample was used cedar of Sanbu region, Chiba
prefecture (size: 1mm) and the catalyst was used sodiumhydroxide. The experimental apparatus is shown in Fig. 1.
The experimental conditions are shown in Table .1.At
first, the biomass and NaOH were loaded into the reactor
and heated by an electric furnace while the flowing
nitrogen and steam warmed by the heater. After theexperiment, the product gas was analyzed by a gas

chromatograph (GC-2014ATF) made by SHIMADZU.
The liquid product was analyzed by GC/MS.

Fig.1 Experiment apparatus of stream gasification
Table1. The experimental condition
Sample(g)Time(h)

Temp:
(ºC)

Temp:
rate

N2 flowrate

Catalyst

102700 ºC5～15ºC /min

30ml/m
in

NaOH：
0～3g

Gasifiedagent
Distillatedwater
1～10ml/min

3. Results and Discussion
Figure 2 shows the impact of the products (liquid, gasand char) according to the amount of stream by using
health cedar (10g) at 700 ºC for 2 hours. From fig.2, weunderstand that tar decreased with increase in theamount of steam added, but the gas was increased.This
is suggested to promote gasification of volatiles bysupplying steam, combustible gas has increased due tothe decomposition of tar reforming reaction. Increase ofthe hydrogen concentration is considered that thefollowing reactions by introducing water vapor
contribution.
C ＋ H2O → CO ＋ H2 (Water gas reaction)
CO ＋ H2O → CO2 ＋ H2 (Shift reaction)

7th International Symposium on Feedstock Recycling of Polymeric Materials (7th ISFR 2013)
New Delhi, India, 23-26 October 2013

80gas60
liquid (tar+water)

40
20char004

8121650
40
3020
10

H200

H2O/C ratio(C=const)

CO4CO281216

H2O/C ratio

Fig.2. Product yield and the effect of the steam suppliedto the gas composition

product of yield [％]5015 ℃/min tar

40

5 ℃/min tar
5 ℃/min char30

case of changing the amount of heating rate and theaddition of NaOH. The disease cedar char yield higher
than healthy cedar but the tar yield is lower. Addition ofless amount of NaOH is difficult to effect the produced
gas in disease cedar. It considered that the difference ofmoisture content and decrease of cellulose components
in disease cedar. When the disease cedar and NaOH
(1 g) were carried out at 700 ºC (H2O / C = 8, 5ºC / min,2h) , the produced gas can get high efficiency of coldgas, carbon conversion and high calorific value gas fuel( 12 ~ 14Mj/Nm3). Table 2 shows the results of theestimated assumption that the gasification gas of diseasecedar is applied to Sanbu region.
80

produced gas [ mol/100-C]

100

Product of gas [mmol]

Product of yield [wt ％]From this experiment, we suggested that the addition ofsteam to the gasification, it is possible to suppress the tar
and promote the hydrogen production for synthesis gas.

40

CO220COH2015 ℃/min char

1230

health cedar

10123diseases cedar
NaOH (g)123Fig.6. Compare of gas health cedar and disease cedar

NaOH [g]Fig.3. Effect of NaOH and heating rate applied to theproduct yield

45yield [%]6040

CH4CO220CO01230

15℃/min

2NaOH (g)Fig.4.. Effect of NaOH and heating rate applied to theproduct gas

4028382624(disease)
Char病
チャー

22(health) Char
健康…

20012NaOH [g ]3yield [wt%]42Carbonconversion
病害炭素転25Cold冷ガスgas efficiency
病害3230(health) Tar
健康タール(disease) Tar病タール1( disease)
効率012
NaOH (g)3Table.2 Estimation results
Expect256980(disease)
換率20(t/y)3634(health)
効率30

Crop30Cold冷ガス
gas efficiency
健康Fig.7.Efficiency comparison of health cedar and disease
cedar

315℃/min32(health)
換率

35H20

Carbonconversion
健康
炭素転4080yield [wt%]

CH4

0200

produced gas [ mol/100-C]

60

gas ofCalorific ofPotential

wood

gas

abundance(m3/t)(Kcal/Nm3)(GJ/y)

2.5×1023057

82211.8

amount(GJ/y)

Thermal57548.2

Generation16442.4

4. Conclusions
23NaOH [g]Fig.5. (a) Comparison of disease and health char(b) Comparison of disease tar and health tar
Effect of NaOH and heating rate applied to the productyield and the influence of heating rate and NaOH applied
to the product gas are shown in in fig. 3 and fig.4. Figure5(a) (b),6,7 are show the comparison result of healthcedar and disease cedar gasification at 700 ºC ,in theThe steam gasification of cedar is possible to promote
the production of hydrogen-rich fuel gas while
suppressing the tar. The efficient gasification is possibleby the synergistic effect of addition of NaOH and heatingrate. The efficiency of disease cedar gasification and gas
production rate is low compared with the healthy cedar,but tar is reduced. By adjusting the experimental
conditions, disease cedar can also produce a highcalorific gas, because it can be expected to avoid tar
problems and possible applied to Sanbu region as a fuelgas.

7th International Symposium on Feedstock Recycling of Polymeric Materials (7th ISFR 2013)
New Delhi, India, 23-26 October 2013