• Journal of the Korean Wood Science and Technology
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• v.43 no.3
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• pp.381-389
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• 2015

In this study, the effects of moisture content and particles size of ground particles of torrefied larch chips on the pelletizing process were investigated depending on torrefaction conditions ($220^{\circ}C$-50 min, $250^{\circ}C$-50 min, $250^{\circ}C$-120 min). The moisture content in the torrefied chip decreased to 0.69~1.75%, while ash content and calorific value increased compared to untreated chip. In addition, weight loss significantly increased during torrefaction due to hemicellulose degradation. The carbon content in torrefied larch chip increased compare to untreated larch chip, while the hydrogen and oxygen contents decreased. The lignin and glucan contents in torrefied larch chip increased with increasing severity of the torrefaction condition, while hemicellulose decreased. In the particle size distribution of ground particles of torrefied larch chip, larch torrefied at severe conditions was found to produce smaller particles (~1 mm) than that of the larch torrefied at mild conditions. Macropore (over $500{\AA}$) in the torrefied particle was produced during torrefaction. During the pelletizing using ground particles of torrefied larch chip, the pressure needed in pelletizing decreased and pellet length increased with increasing moisture content, regardless of the particle size.

• Journal of the Korean Wood Science and Technology
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• v.43 no.1
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• pp.122-134
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• 2015

This study was conducted to investigate the potential of torrefied larch wood as a raw material of pellets. First of all, larch chip was torrefied at the temperatures of 230, 250 and $270^{\circ}C$ for 30, 50 and 70 min. Secondly, moisture content, moisture absorption, higher heating value and ash content of the torrefied chip were measured to examine the effects of torrefaction conditions on the fuel characteristics of larch. Thirdly, surfaces of the torrefied chip were observed by light microscope (LM), field emission scanning microscope (FE-SEM) and SEM-energy dispersive spectroscopy (EDXS). With the increases of torrefied temperature and time, contents of lignin increased and those of hemicellulose reduced. Moisture content of torrefied larch chip was greatly lower than that of non-torrefied chip. Moisture absorption of the torrefied chip decreased as torrefaction temperature increased. As torrefaction temperature increased, higher heating value and ash content of larch chip increased. However, durability of torrefied-larch pellets was remarkably lower comparing to non-torrefied-larch pellets. When surface of larch chip was observed by LM and FE-SEM, surface color and cell wall of the chip was getting darker and more collapsed with the increases of torrefaction conditions. Through the analysis of SEM-EDXS, distribution and quantity of lignin existing on the surface of larch chip increased with the increases of torrefied conditions. In conclusion, $270^{\circ}C$/50 min might be an optimal condition for the torrefaction of larch with the aspect of fuel characteristics, but torrefaction condition of $230^{\circ}C$/30 min should be considered according to the durability of torrefied-larch pellets.

• Korean Chemical Engineering Research
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• v.53 no.2
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• pp.224-230
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• 2015

This study was conducted to investigate the effects of several variables on the durability of wood pellets fabricated with torrefied larch (LAR) and tulip tree (TUT) chips. Microscopic observation by scanning electron microscope-energy dispersive X-ray spectrometer was also performed to identify the surface of the wood pellets visually. In addition, torrefied-LAR and TUT pellets were fabricated with the addition of moisture, lignin, starch and protein as binders, and durabilities of the pellets were analyzed statistically. Durabilities of torrefied-LAR and TUT pellets were lower than one of non-torrefied-LAR and TUT pellets. Durabilities of both pellets fabricated with the wood chips, which were torrefied with $230^{\circ}C$ and 30 min, were the highest among all torrefaction conditions used in this study. From the microscopic observations, lignin was distributed broadly on the surface of non-torrefied wood pellets, whereas congregated partially on the surface of torrefied wood pellets. Durability of LAR pellets increased with the addition of moisture, but that of TUT pellets was reduced. Addition of binders contributed to increase the durability of LAR and TUT pellets. As a binder, lignin and protein were more effective than starch for improving the durability. In conclusion, mild torrefaction treatment, such as $230^{\circ}C$ and 30 min, might be an optimal condition to minimize the durability reduction of the LAR and TUT pellets. In addition, when torrefied woody materials with high and low specific gravities are used as a raw material for the production of durable wood pellets, it might be required to adjust moisture content and torrefaction conditions of woody materials, respectively.

• Journal of the Korea Furniture Society
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• v.28 no.2
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• pp.111-117
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• 2017

Recently, as people's interest in wood has increased, the use of wood as household and landscape decking materials has increased. As the deck material, imported wood such as synthetic wood, Ipe, and Malas was used in addition to the existing preserved wood, but recently deck use has been activated as part of the activation of domestic materials. As an important quality factor in the selection of such decking materials, various durability along with weatherability for long - term use is required for maintenance. Generally used tropical hardwoods have excellent weatherability and durability without additional preservative treatment. However, the domestic larch is a wood species with a higher specific gravity and durability than ordinary conifers. However, it has not yet been used as a deck material due to lack of comparative studies on its characteristics. Therefore, hardness and durability of wood were measured using six specimens of Ipe, Massaranduba, Malas, Douglas-fir, Larch and Torrefied-Larch. Density Profile was used to measure the density, and Brinell hardness test and resistance test against momentary impact were carried out for the test of resistance to static load. Also, The hardness and durability of wood were measured by castor test with resistance test against dynamic load, as well as, nail down test by experiment on surface hardness and durability. As a result of the experiment, the hardness was increased in proportion to the density, and it was confirmed that the imported lumber was harder and durable than the domestic larch.

• Korean Chemical Engineering Research
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• v.51 no.6
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• pp.739-744
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• 2013

In this study, torrefaction was performed to improve fuel properties of Larch. The optimal condition for torrefaction was investigated by response surface methodology. The torrefaction temperature and time ranged $220{\sim}280^{\circ}C$ and 20~80 min, respectively. As the torrefaction temperature and time increased, the carbon content of torrefied biomass increased from 49.36 to 56.65%, while its hydrogen and oxygen contents decreased from 5.56 to 5.48% and from 37.62 to 31.67%, respectively. The weight loss and calorific value increased with SF, while energy yield decreased. At the severe torrefaction condition (SF 7), the weight loss and calorific value were 26.58% and 22.30 MJ/kg, respectively. The energy contained in torrefied biomass increased to 20.41%, when compared with the untreated biomass. As the torrefaction severity increased, the energy yield decreased due to the relatively high weight loss of biomass. Therefore, the highest energy yield was obtained at high calorific value and low weight loss of biomass (SF 5.72).