Journal of the Korean Wood Science and Technology

The Korean Society of Wood Science & Technology (한국목재공학회)
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Effect of Torrefaction Condition on The Chemical Composition and Fuel Characteristics of Larch wood

낙엽송재의 화학적 조성 및 연료적 특성에 대한 반탄화 조건의 영향

  • Kim, Sang Tae (Department of Wood and Paper Science, College of Agriculture, Life & Environments Sciences, Chungbuk National University) ;
  • Lee, Jae-Jung (Division of Wood Chemistry & Microbiology, Department of Forest Products, Korea Forest Research Institute) ;
  • Park, Dae-Hak (Department of Wood and Paper Science, College of Agriculture, Life & Environments Sciences, Chungbuk National University) ;
  • Yang, In (Department of Wood and Paper Science, College of Agriculture, Life & Environments Sciences, Chungbuk National University) ;
  • Han, Gyu-Seong (Department of Wood and Paper Science, College of Agriculture, Life & Environments Sciences, Chungbuk National University) ;
  • Ahn, Byoung Jun (Division of Wood Chemistry & Microbiology, Department of Forest Products, Korea Forest Research Institute)
  • 김상태 (충북대학교 농업생명환경대학 목재종이과학과) ;
  • 이재정 (국립산림과학원 임산공학부 화학미생물과) ;
  • 박대학 (충북대학교 농업생명환경대학 목재종이과학과) ;
  • 양인 (충북대학교 농업생명환경대학 목재종이과학과) ;
  • 한규성 (충북대학교 농업생명환경대학 목재종이과학과) ;
  • 안병준 (국립산림과학원 임산공학부 화학미생물과)
  • Received : 2014.05.05
  • Accepted : 2014.05.27
  • Published : 2015.01.25
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Abstract

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.

본 연구는 낙엽송을 이용한 반탄화 펠릿의 제조 가능성을 확인하기 위하여 수행하였다. 낙엽송 칩을 230, 250, $270^{\circ}C$ 및 30, 50, 70분의 조건에서 반탄화 처리를 각각 실시하였으며, 반탄화 낙엽송 칩의 함수율, 수분흡착률, 발열량, 회분을 측정하여 각 조건에 대한 반탄화 조건의 영향을 분석하였다. 또한 반탄화 낙엽송 칩의 표면을 광학현미경, FE-SEM, SEM-EDXS를 이용하여 관찰하였다. 낙엽송 시편의 리그닌 함량은 반탄화 온도 및 시간 증가와 함께 증가한 반면, 전섬유소 함량은 감소하였다. 함수율은 반탄화 처리하지 않은 칩과 비교하여 급격히 감소하였으며, 수분흡착률은 반탄화 온도가 높을수록 감소하였다. 낙엽송의 발열량 및 회분함량은 반탄화 온도가 높아짐에 따라 증가하였으나, 반탄화 낙엽송 펠릿의 내구성은 무반탄화 낙엽송 펠릿과 비교하여 현저히 낮았다. 낙엽송 칩의 단면을 광학현미경 및 FE-SEM으로 관찰한 결과 반탄화 조건이 강해질수록 재색의 농색화 및 세포벽의 부분적 붕괴를 확인할 수 있었으며, SEM-EDXS 분석을 통하여 반탄화에 따른 리그닌의 분포 확산 및 양의 증가가 확인되었다. 결과를 종합하면, 연료적 특성의 측면에서 $270^{\circ}C$/50분이 낙엽송의 최적 반탄화 조건인 것으로 판단되나, 낙엽송 반탄화 펠릿의 내구성 결과에 따르면 $230^{\circ}C$/30분과 같이 반탄화 처리조건이 강하지 않은 경우에 대하여 고려할 필요성이 있을 것으로 생각한다.

Keywords

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