Upgraded Pellet Making by Torrefaction—Torrefaction of Japanese Wood Pellets

DOI: 10.4236/jsbs.2015.53008

Author(s)   

Takahiro Yoshida^1*, Takashi Nomura², Hideki Gensai², Hiroki Watada², Tetsuya Sano^1,3, Seiji Ohara¹

Affiliation(s)

¹Forestry and Forest Products Research Institute, Tsukuba, Japan.

²Fukui Prefectural Green Center, Sakai, Japan.

³Present Address: Tohoku Institute of Technology, Sendai, Japan.

ABSTRACT

Upgraded wood pellets were produced and evaluated by torrefaction of wood pellets. In this study, conventional wood pellets were initially prepared and subsequently torrefied on a laboratory and then larger scale. During the laboratory scale production, pellets from wooden parts of Japanese cedar (sugi, Cryptomeria japonica) and Japanese oak (konara, Quercus serrata) trees were heat- treated in an inert gas oven under nitrogen atmosphere around 170°C - 320°C. For the Japanese cedar, the calorific values were improved by heat treatment up to 260°C. By heat treatment at 240°C, the upgrade ratio of higher heating value (HHV) was nearly 30% and the energy yield was 97%. For the Japanese oak, the calorific values were improved by heat treatment up to 320°C. By heat treatment at 280°C, the upgrade ratio of HHV exceeded 30% and the energy yield was 84%. On a larger scale, a conventional charcoal oven was modified for torrefied wood pellet production, meaning that torrefied wood pellet with 25 MJ/kg of calorific value was produced during heat treatment at 350°C. A mixture of conventional and torrefied pellets was applied to a commercial pellet stove, and torrefied wood pellets produced in this study might be usable as fuel for conventional pellet stoves.

KEYWORDS

Component, Wood Pellet, Torrefaction, Calorific Value

Cite this paper

Yoshida, T. , Nomura, T. , Gensai, H. , Watada, H. , Sano, T. and Ohara, S. (2015) Upgraded Pellet Making by Torrefaction—Torrefaction of Japanese Wood Pellets. Journal of Sustainable Bioenergy Systems, 5, 82-88. doi: 10.4236/jsbs.2015.53008.

References

[1]	Ministry of Agriculture, Forestry and Fisheries, Japan (2015) Annual Report on Trends in Forest and Forestry in Japan. Ministry of Agriculture, Forestry and Fisheries, Tokyo.
[2]	Deutmeyer, M. (2012) 2 Torrefaction Technologies and Initiatives for Improving Biomass Feedstock Specifications: Possible Effect of Torrefaction on Biomass Trade. IEA Bioenergy Task 40.
[3]	van der Stelt, M.J.C., Gerhauser, H., Kiel, J.H.A. and Ptasinski, K.J. (2011) Biomass Upgrading by Torrefaction for the Production of Biofuels: A Review. Biomass and Bioenergy, 35, 3748-3762. http://dx.doi.org/10.1016/j.biombioe.2011.06.023
[4]	Bergman, P.C.A., Boersma, A.R. and Kiel, J.H.A. (2007) Torrefaction for Biomass Conversion into Solid Fuel. Proceedings of the 15th European Biomass Conference and Exhibition, Berlin, 7-11 May 2007, 78-81.
[5]	Uslu, A., Faaij, P.C.A. and Bergmann, P.C.A. (2008) Pre-Treatment Technologies, and Their Effect on International Bioenergy Supply Chain Logistics. Techno-Economic Evaluation of Torrefaction, Fast Pyrolysis and Pelletisation. Energy, 33, 1206-1223. http://dx.doi.org/10.1016/j.energy.2008.03.007
[6]	Stelte, W., Clemons, C., Holm, J.K., Sanadi, A.R., Ahrenfeldt, J., Shang, L. and Henriksen, U.B. (2011) Pelletizing Properties of Torrefied Spruce. Biomass and Bioenergy, 36, 4690-4698. http://dx.doi.org/10.1016/j.biombioe.2011.09.025
[7]	Misljenović, N., Bach, Q.V., Tran, K.Q., Salas-Bringas, C. and Skreiberg, O. (2014) Torrefaction Influence on Pelletability and Pellet Quality of Norwegian Forest Residues. Energy Fuels, 28, 2554-2561. http://dx.doi.org/10.1021/ef4023674
[8]	Romeo, J.C. and Barno, J. (2008) Evaluation of Torrefaction + Pelletization Process to Transform Biomass in a Biofuel Suitable for Co-Combustion. Proceedings of the 16th European Biomass Conference and Exhibition, Valencia, 2-6 June 2008, 1937-1941.
[9]	Repellin, V., Govin, A., Rolland, M. and Guyonnet, R. (2010) Energy Requirement for Fine Grinding of Torrefied Wood. Biomass and Bioenergy, 34, 923-930. http://dx.doi.org/10.1016/j.biombioe.2010.01.039
[10]	Peng, J.H., Bi, H.T., Sokhansanj, S. and Lim, J.C. (2012) A Study of Particle Size Effect on Biomass Torrefaction and Densification. Energy Fuels, 26, 3826-3839. http://dx.doi.org/10.1021/ef3004027
[11]	Saleh, S.B., Hansen, B.B., Jensen, P.A. and Dam-Johansen, K. (2013) Efficient Fuel Pretreatment: Simultaneous Torrefaction and Grinding of Biomass. Energy Fuels, 27, 7531-7540. http://dx.doi.org/10.1021/ef401787q
[12]	Yoshida, T., Sano, T., Nomura, T., Gensai, H., Watada, H. and Ohara, S. (2013) Fundamental Study on the Production of “Hyper Wood Pellet”—Effect of Torrefaction Condition on Grinding and Pelletizing Properties. Journal of Energy and Power Engineering, 7, 705-710.
[13]	Ren, S., Lei, H., Wang, L., Bu, Q., Wei, Y., Liang, J., Liu, Y., Julson, J., Chen, S., Wu, J. and Ruan, R. (2012) Microwave Torrefaction of Douglas Fir Sawdust Pellets. Energy Fuels, 26, 5936-5943. http://dx.doi.org/10.1021/ef300633c
[14]	European Committee for Standardization (2009) Solid Biofuels—Determination of Bulk Density, EN 15103:2009.

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