• Journal of the Korean Wood Science and Technology
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• 제50권2호
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• pp.126-133
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• 2022

In this study, I used wood pellets as an eco-friendly sound-absorbing material. The aim of the research was to analyze the effect of the filling height of wood pellets on sound absorption. This was done using two types of wood pellets of different lengths (A group: 1.5-3 cm, B group: less than 1.5 cm). With increasing filling height of the wood pellets, the optimum sound absorption shifted towards a lower frequency. The group B wood pellets had better sound absorption capacity than the group A ones. The optimum sound absorption coefficient of group A filled to a height of 7 cm was 0.722 at 864 Hz. On the other hand, that of group B filled to a height of 7 cm was 0.764 at 862 Hz, 5.82% higher than that of group A. While wood pellets are used as an eco-friendly fuel, the results of this study suggest the possibility of using wood pellets as an eco-friendly sound-absorbing material.

• Journal of the Korean Wood Science and Technology
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• 제46권5호
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• pp.541-552
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• 2018

목재펠릿 사용량이 증가함에 따라 사용하는 사람과 환경에 물리적 화학적 피해가 발생하지 않도록 목재펠릿 자체의 안전성에 대한 관심이 증가하고 있다. 본 연구는 목재펠릿의 안전성평가 기준 제정을 위한 예비조사로서, 국내에서 유통 중인 목재펠릿의 질소, 황, 염소, 비소, 카드뮴, 크롬, 구리, 납, 수은, 니켈, 아연, 세슘방사능의 함유량을 조사하였다. 국내산 목재펠릿의 질소, 황, 염소 및 중금속 함유량은 국립산림과학원의 목재펠릿 품질 1급 기준과 ISO의 비산업용 목재펠릿 A1급 기준 및 목재펠릿 안전성 평가기준을 만족하였다. 그러나 수입 목재펠릿의 경우 일부 목재펠릿의 질소, 황, 염소 및 중금속 함유량이 안전성 평가기준의 허용량을 초과하였다. 국내산 목재펠릿에서는 세슘방사능이 검출되지 않았다. 일본으로부터 수입된 목재펠릿으로부터는 세슘방사능이 검출되었으나, 목재펠릿 안전성평가 기준에 규정된 허용량을 하회하였다. 결론적으로 목재펠릿 안전성 평가기준 설정은 안전한 목재펠릿 이용에 기여할 것으로 판단된다.

• Journal of the Korean Wood Science and Technology
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• 제47권1호
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• pp.110-123
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• 2019

This work was conducted to examine the relationship between lignin content and the durability of larch (LAR) pellets. LAR sawdust was immersed in tap water (TW), sulfuric acid (AC) and sodium hydroxide (AK) solutions, and then the immersed sawdust was used for pellet fabrication. Klason lignin (KL) content of the immersed LAR, contents of soluble lignin (SL) and monomeric sugars liberated from the immersion of LAR, and durability of LAR pellets were measured. KL content decreased as the concentration of AC and AK solutions increased, but glucose content increased with increase in AC and AK concentration. Durability of wood pellets fabricated using non-immersed LAR sawdust was the highest, followed by those made using TW-, AK- and AC-immersed sawdust. LAR pellets became more durable as the concentration of KL and SL increased, but a significant positive correlation was found only between pellet durability and KL content. Through the fluorescent microscopic observation and SEM-EDX analysis, it was verified that lignin content of non-immersed LAR pellets was higher than that of AC- and AK-immersed LAR pellets. These results suggest that lignin might contribute to an increase in inter-particle bonding in wood pellets.

• Journal of the Korean Wood Science and Technology
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• 제51권5호
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• pp.381-391
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• 2023

Densification is a technique used to improve biomass quality in wood pellet manufacturing and torrefaction treatment. In this study, the effects of torrefaction on the quality of Calliandra wood pellets were investigated, and pellets of Calliandra wood (Calliandra calothyrsus) and bark were evaluated. The study was conducted using a completely randomized design with two treatment factors, namely torrefaction temperature (250℃ and 300℃) and torrefaction duration (30, 45, and 60 min). The results showed that the interaction between temperature and torrefaction duration significantly affected the compressive strength, proximate value, and calorific value of the torrefied Calliandra wood pellets. An increase in the temperature and torrefaction duration decreased the compressive strength, moisture content, volatile matter content, and ash content of the torrefied Calliandra wood pellets. Conversely, the calorific value of Calliandra wood pellets increased with increasing temperature and torrefaction duration. The best-quality Calliandra wood pellets were produced at a torrefaction temperature and duration of 300℃ and 60 min, respectively. In terms of important quality parameters, ash content of 0.90% and calorific value of 6,303.80 cal/g were observed, which complied with the quality standards of Indonesian National Standard 8675:2018 and Deutsche Industrie Norm 51731.

• Journal of the Korean Wood Science and Technology
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• 제38권1호
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• pp.36-42
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• 2010

본 연구에서는 소나무재와 굴참나무재의 톱밥을 이용하여 제조한 목재펠릿과 두 수종의 톱밥에 목타르를 혼합하여 제조한 펠릿의 특성에 대해서 조사하였다. 펠릿은 상온에서 만능강도측정기를 이용하여 2000 kgf/$cm^2$의 압력을 가하여 제작하였다. 목재펠릿의 밀도는 굴참나무 톱밥으로 제조한 것이 소나무 톱밥으로 제조한 것보다 다소 높았고, 미세분 발생량은 굴참나무 톱밥으로 제조한 펠릿이 소나무 톱밥으로 제조한 펠릿보다 낮았다. 발열량은 소나무 톱밥으로 제조한 펠릿이 굴참나무 톱밥으로 제조한 펠릿보다 다소 높았다. 톱밥과 목타르를 혼합하여 제조한 펠릿은 목타르 함량이 증가함에 따라 함수율, 밀도 및 발열량이 높게 나타났고, 미세분 발생량은 적었다. 이상의 결과로부터 목타르는 고품질 펠릿제조를 위한 원료로서의 이용이 기대된다.

• 한국대기환경학회지
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• 제33권4호
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• pp.403-410
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• 2017

With the growing importance of GHG reduction, wood pellets are considered as a cheaper renewable energy and carbon neutral. On the other hand, there is a concern that the burning wood pellets may release even more air pollutants such as CO and VOCs. In this study, we analyzed the social costs of burning fuels including wood pellets and coals based on the unit calorific value. The social costs were calculated by sum of the import costs of the fuels and the emission costs of the air pollutants. The results showed that wood pellets are inferior to coals in the aspect of the social costs. It is necessary to improve the quality of the wood pellets and pellet boiler facilities for being used eco-friendly energy sources in the future. We suggest that the control facilities of CO and VOCs should be installed, if the control costs are lower than the pollution costs.

• Journal of Forest and Environmental Science
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• 제30권4호
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• pp.362-369
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• 2014

This study investigated physical properties and combustion gas characteristics for 8 types of wood pellets (4 domestic and 4 imported products) distributed in the domestic market. Results showed that most pellet types were first-grade pellets in the wood pellet quality standards in Korea with the exception of 3 pellet types from K company (second-grade in mechanical durability), G company (off-grade in nitrogen content) and P company (second-grade in ash percentage). Mixed pellets which contained more lignin and sap content were higher in mechanical durability (%) than that of white pellets. From the combustion gas analysis results, NOx emitted from all pellets combustion was at acceptable levels for national emission standard of the Clean Air Conservation Act except for pellets from G company. In addition, CO levels from all types of wood pellets were acceptable except for pellets from D company and domestic pellets were higher CO levels than imported pellets. These results indicate the higher CO levels in domestic pellets due to the usage of forest thinning materials including logging debris which usually had the high content of bark.

• Journal of the Korean Wood Science and Technology
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• 제41권6호
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• pp.475-489
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• 2013

본 연구는 낙엽송과 백합나무 톱밥을 이용한 펠릿의 제조 과정에서 바인더로 일정량의 유채박, 커피부산물, 수피, 솔방울, 리그닌 분말을 첨가하여 바인더의 종류 및 첨가량이 내구성을 포함한 펠릿의 품질에 미치는 영향을 알아보기 위하여 수행하였다. 바인더와 함께 제조한 펠릿의 품질은 국립산림과학원에서 고시한 목재 펠릿 품질 규격 1등급 기준을 대부분 상회하였으며, 일부 과다한 양의 바인더를 첨가하여 제조한 펠릿에서만 높은 회분 함량으로 2~3등급 기준을 만족하는 것으로 조사되었다. 바인더 종류 및 첨가량에 따른 펠릿의 내구성은 리그닌, 유채박 그리고 커피부산물을 첨가하여 제조한 펠릿에서 우수하였으며, 백합나무 펠릿은 첨가량의 증가와 함께 내구성도 향상되었다. 한편 낙엽송 펠릿의 경우 첨가량의 증가에 따른 내구성 향상 효과는 크지 않았으며, 수피와 솔방울을 바인더로 사용하였을 때 첨가량의 증가와 함께 내구성이 감소하였다. 제조된 펠릿의 광학/전자현미경 관찰을 통하여 바인더의 종류에 따른 차이를 명확하게 확인할 수 없었으나, 첨가량에 따른 차이는 명확하게 관찰할 수 있었다. 결과를 종합하면, 바인더의 첨가는 목재 펠릿의 품질 향상에 대부분의 항목에서 기여하였으며, 특히 커피부산물을 바인더로 사용하여 제조한 펠릿의 경우 모든 품질에서 뚜렷한 향상을 확인할 수 있었다. 향후 저렴한 바인더의 안정적인 확보가 이루어진다면 바인더의 첨가로 인하여 연료적 품질이 향상된 목재 펠릿의 상용화가 가능할 것으로 확신한다.

• Journal of the Korean Wood Science and Technology
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• 제51권1호
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• pp.23-37
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• 2023

One type of biomass that has promising potential for bio pellet production is spent coffee grounds (SCGs). However, previous studies have shown that SCGs in bio pellets cause a lot of smoke. Therefore, they need to be mixed with a material that has a higher calorific value to produce better quality pellets. One material that can be used is pine wood because it has a natural resin content that can increase the calorific value. The aim of this study was to examine the quality of bio pellets produced with SCGs and pine wood charcoal at different particle sizes. The charcoal was ground using either a hammer mill (HM) or a ball mill (BM). Pine wood charcoal was mixed with SCGs at ratios of SCGs to pine wood charcoal of 4:6 and 6:4 by weight, respectively, and the adhesive used a tapioca with a composition ratio 5% of the raw material. The bio pellets were produced using a manual pellet press. The quality of the bio pellets was assessed based on Indonesian National Standard (SNI) 8021-2014, and the physical observations include flame length, burning rate, and compressive strength. The average water content, ash content, and calorific value of the bio pellets were in accordance with SNI 8021-2014, but the density and ash content values were below the standard values. The BM variation of bio pellets had a higher compressive strength than the HM variation, and the 4:6 BM variation had the longest burning time compared with 4:6 HM.

• Journal of Forest and Environmental Science
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• 제25권2호
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• pp.127-130
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• 2009

This study has been carried out to investigate the characteristics of the commercial wood pellets such as moisture content, heating value, ash content, and chemical component. The wood pellets from national forestry cooperatives federation and China were evaluated to see if they can be 1st or 2nd class of Korea standard. Indonesian pellet was estimated to be a 3rd class because of the heating value and high ash content. It is considered that there is a quality difference in wood pellets in accordance with the production nations. It could be originated from the difference of raw materials produced in different region.