Abstract

This study was conducted to investigate the effects of a number of factors (moisture content and particle size of sawdust and operating time of flat-die pelletizer) on the fuel characteristics of wood pellets fabricated from Mongolian oak (MOK) and pitch pine (PCP) sawdust. MOK and PCP pellets were produced from sawdust of varying moisture content (8, 10, 12%) and was screened to mesh sizes of 2 and 4 (0.64 and 1.27 mm). Moisture content (MC), bulk density (BD) and durability (DU) of the produced pellets were also determined based on the operating time of the flat-die pelletizer (10, 20, 30, 40, 50 And 60 min). The MC of both MOK and PCP pelletswere not altered based on their duration in the flat-die pelletizer. However, the BD and DU of MOK pellets were higher than those of PCP pellets. Increasing the MC of the sawdust resulted in an increase in pellet MC and BD, reducing their fuel value. The BD of PCP pellets was greatly decreased when sawdust with a MC of 12% was applied. The DU of both MOK and PCP pellets increased when the MC was increased from 8% to 10%. However, no further increase in DU occurred through the use of MOK sawdust with a MC of 12%, and the DU of PCP pellets was reduced through the use of a MC of 12%. Pellet MC, BD and DU were not influenced by the particle size of sawdust, or by the operating time of flat-die pelletizer. On the other hand, BD and DU of MOK and PCP pellets were lower than those of Larch pellets which, having very suitable characteristics, were used as a reference pellet in this study. In conclusion, MOK pellets with suitable fuel characteristics, satisfying the minimum requirement of the 1st-grade pellet standard designated by the Korea Forest Research Institute, were produced. However, the BD and DU of PCP pellets were lower than the standard, and especially, the DU of PCP pellets produced with the sawdust MC of 12% was inferior to the standard for 4th-grade pellets (?95.0%). Based on the results, 10% MC for MOK sawdust might beoptimal for the production of MOK pellets, but PCP alone is not suitable as a raw material for the production of wood pellets under the experimental conditions examined in this study.

Keywords

• Wood pellets;
• Mongolian oak;
• Rigida pine;
• Fuel characteristics;
• Flat-die pelletizer;
• Moisture content;
• Particle size

• 목재 펠릿;
• 신갈나무;
• 리기다소나무;
• 연료적 특성;
• 평다이 펠릿성형기;
• 함수율 목분 크기;