근적외선 분광법을 이용한 열수 탄화 리그닌의 탄화 거동 예측 모델 개발

여환명 ( Hwanmyeong Yeo ),황성욱 ( Sung-wook Hwang ),이태경 ( Tae-kyeong Lee ),황운택 ( Un Taek Hwang ),김종찬 ( Jong-chan Kim ),최인규 ( In-gyu Choi ),박진석 ( Jinseok Park ),곽효원 ( Hyo Won Kwak ) 한국목재공학회 2021 한국목재공학회 학술발표논문집 Vol.2021 No.1

펄핑 공정의 부산물인 크라프트 리그닌을 이용하여 고성능 흡착재료를 개발하기 위한 전처리 단계로서 열수 탄화(hydrothermal carbonization, HTC)를 수행하였다. 열수 탄화는 유기성 폐기물 바이오매스를 일정 온도까지 승온시켜 탈수 반응을 유도하여 고형연료화를 도모하는 공정이다. 고액비 2/50의 리그닌 분말과 증류수의 현탁액을 온도 200℃에서 각각 1, 2, 3, 5, 10시간 동안 열수 탄화 후 자연 냉각하였다. 원소 분석기를 이용하여 HTC 리그닌 시료의 원소 조성을 조사하였으며, 근적외선(near-infrared, NIR) 스펙트럼을 측정하였다. NIR 스펙트럼은 2차 미분으로 전처리하였다. 탄소 함량은 열수 탄화 시간의 증가와 함께 증가하였으나 3시간 이후에는 유사한 수준이 유지되었다. 최소 제곱 회귀(partial least squares regression, PLSR)를 이용하여 NIR 스펙트럼을 입력 변수로 그리고 C(wt%), H/C, O/C를 각각 출력 변수로 하는 예측 모델을 수립하였다. 수립된 예측 모델은 모든 출력 변수를 결정 계수(R²) 0.9 이상의 높은 정확도로 예측하였다. NIR 스펙트럼의 전처리 여부에 상관없이 모델의 성능은 비슷하였다. PLSR 모델의 C 예측 성능은 R² 0.942였으며, 이 수치는 일반 최소 제곱 회귀 모델의 0.834를 크게 앞선다. 회귀 계수 분석으로부터 1450 nm 스펙트럼 영역에 할당된 리그닌의 페놀기가 탄화 거동을 설명하는 중요한 영역이라는 것이 확인되었다. NIR과 PLSR을 이용하여 HTC 리그닌의 탄화 특성을 빠르고 정확하게, 그리고 비파괴적으로 예측할 수 있었다.

리기다소나무 원목형질 조사 및 구조용집성재 제조 수율 평가

심상로,여환명 한국목재공학회 2004 목재공학 Vol.32 No.2

우리나라 전역에 사방 및 연료림으로 대량 식재되어 소기의 목적을 달성함과 동시에 치산녹화 성공을 이루는데 크게 기여한 수종인 리기다소나무 제재목의 구조용집성재 라미나로서의 이용가능성을 고찰하였다. 건전한 임분 내에서 평균 흉고직경 32 ㎝인 리기다소나무를 벌채하여 말구직경 15 ㎝ 이상으로 조재하였을 경우 80% 이상이 2등급 또는 3등급의 원목형질로 구분되어 리기다소나무의 제재목으로서의 이용가능성이 높다고 판단되었다. 구조용집성재 라미나용 주제품의 제재수율은 39.9%. 벽판재 수율은 7.2%, 부제품 수율은 8.1%로 총 원목의 55.2%가 판재로 제재되었다. 옹이를 제거하여 핑거가공한 후 제조한 구조용집성재의 제조수율은 15.3%로 평가되어 옹이를 제거하지 않은 판재의 라미나로의 이용을 위한 옹이채의 휨강도와 압축강도 등의 강도적 성능 평가와 더불어 최적의 라미나 배열을 통한 구조용집성재의 강도 감소 최소화를 위한 연구가 앞으로 필요하다고 판단된다. 본 연구에서 조사된 제재수율과 기타 가공수율 평가는 현재까지 목재산업현장에서 제재목으로의 이용이 거의 이루어지지 않고 있는 리기다소나무의 효율적인 생산계획을 수립하는데 사용되어질 수 있으리라 기대된다. Pitch pine(Pinus rigida) has been planted in Korean forests for several decades, primarily for erosion control and use as a fuel supply. To enhance its value, and especially potential use as lamina for structural glued laminated timber (glulam), log quality and lumber yield of pitch pine were evaluated in this study. Threes from pure pitch pine stands with an average diameter at trreast hight of 32㎝ were felled and bucked into 3.6m long 15㎝ minimum butt-end diameter logs. Over 80% of the logs were classified to No. 2 or No. 3 visual grade group. Upon sawing total lumber yield was 55.2% 39.9% for structural glulam lamina, 7.2% for louver, and 8.1% for miscellaneous use. The final lumber yield for manutacturing structural glulam, after cross-cutting to eliminate knots and finger jointing, was only 15.3%. To enhance this manutacturing yield requires that the rate of knot-included lumber used as lamina be raised. However arrangement of the knot-inclucled lamina, whose mechanical properties need to he accurately evaluated, must be optimized to minimize any reduction to the structural glulam strength. The log quality and lumber yield of pitch pine evaluated in this study are expected to facilitate proper planning for wood product manufacture in the Korean lumbering and glulam industrial field, which has not previously dealt with this species.

Predicting Lamina Yield from Logs of Different Diameters for Cross Laminated Timber Production

Gi Young Jeong,Jun Jae Lee,Hwanmyeong Yeo,So Sun Lee 한국목재공학회 2016 목재공학 Vol.44 No.6

The goal of this study was to predict lamina yield from logs of different diameter for production of cross laminated timber. Log characteristics of red pine (Pinus densiflora) and Japanese cedar (Pryptomeria japonica), including diameter, length, volume, and defects were used for statistical and geometrical analyses, along with the lamina characteristics, including width, thickness, and defects. Based on the data obtained, the strong factors influencing the yield and grade of lamina from the two species were statistically evaluated. A geometrical approach was used for analysis of the yield from logs of given diameters. Statistical analysis showed that lamina yield was dependent on target lamina size but the grade of lamina was not related to any of the log characteristics. The suggested yield equations from the geometrical approach indicated an accuracy of less than 20% difference.

Hygroscopic Property of Heat Treated Yellow Poplar (Liriodendron tulipifera) Wood

( Yoon-Seong CHANG ),( Yeonjung HAN ),( Chang-Deuk EOM ),( Sangjin CHUN ),( Hwanmyeong YEO ) 한국목재공학회 2019 목재공학 Vol.47 No.6

In modern societies, people spend most of their time indoors and the temperature and humidity controlled by electrical appliances have a considerable effect on their emotions and health. However, improper operation of the artificial facilities frequently creates substances that are harmful to our body. The importance of controlling the natural humidity of interior materials has therefore attracted significant attention. This study was aimed at quantifying the hygroscopic property of some interior finishing wooden materials. Dried and heat-treated yellow poplar (Liriodendron tulipifera) lumbers, oriented strand board, and plywood were selected for this experiment. The moisture adsorption and desorption rates of wooden materials were measured (ISO 24353). Furthermore, the effects of morphological, physical and chemical factors, such as surface microstructure, roughness, and functional groups, on the hygroscopicity were evaluated. The results of this study should contribute to improved accuracy of hygroscopic-property assessments performed on wooden interior materials.

전도가열 급해압처리 목재의 셀룰로오스 분자량 변화 연구

강주원(Juwon Kang),정명준(Myung-Joon Jeong),여환명(Hwanmyeong Yeo),강규영(Kyu-Young Kang) 한국펄프·종이공학회 2016 한국펄프·종이공학회 학술발표논문집 Vol.2016 No.4

Optimization of The Organosolv Pretreatment of Yellow Poplar for Bioethanol Production by Response Surface Methodology

Ho Yong Kim,Chang Young Hong,Seon Hong Kim,Hwanmyeong Yeo,In Gyu Choi 한국목재공학회 2015 목재공학 Vol.43 No.5

We investigated the optimization of the organosolv pretreatment of yellow poplar for bioethanol production. Response surface methodology was used to determine the optimal conditions of three independent variables (reaction temperature, reaction time, and sulfuric acid (SA) concentration). Reaction temperature is the most significant variable in the degradation of xylan and lignin in the presence of an acid catalyst, and ethanol production increased with a decrease in the lignin content. The highest ethanol concentration (42.80 g/ℓ) and theoretical ethanol yield (98.76%) were obtained at 152℃ (2.5 bar) with 1.6% SA for 16 min. However, because of excessive degradation of the raw material, the overall ethanol yield was less than under other pretreatment conditions which has approximately 50% of WIS recovery rate after pretreatment. The optimal conditions for the maximum overall ethanol yield (146℃ with 1.22% SA for 15.9 min) were determined with a predicted yield of 17.11%, and the experimental values were very close (17.15%). Therefore, the quadratic model is reliable.

Quantification of Carbon Reduction Effects of Domestic Wood Products for Valuation of Public Benefit

( Yoon-seong Chang ),( Sejong Kim ),( Kwang-mo Kim ),( Hwanmyeong Yeo ),( Kug-bo Shim ) 한국목재공학회 2018 목재공학 Vol.46 No.2

This study was carried out to quantify degree of contribution of harvested wood product (HWP) on mitigation of climate change by valuation of public benefits, environmentally and economically. The potential carbon dioxide emission reduction of HWP was estimated by accounting carbon storage effect and substitution effect. Based on 2014 statistics of Korea Forest Service, domestic HWPs were sorted by two categories, such as wood products produced domestically from domestic and imported roundwood. The wood products were divided into seven items; sawnwood, plywood, particle board, fiberboard (MDF), paper (including pulp), biomass (wood pellet) and other products. The carbon stock of wood products and substitution effects during manufacturing process was evaluated by items. Based on the relevant carbon emission factor and life cycle analysis, the amount of carbon dioxide emission per unit volume on HWP was quantified. The amounts of carbon stock of HWP produced from domestic and from imported roundwood were 3.8 million tCO_2eq., and 2.6 million tCO_2eq., respectively. Also, each reduction of carbon emission by substitution effect of HWP produced from domestic and imported roundwood was 3.1 million tCO_2eq. and 2.1 million tCO_2eq., respectively. The results of this study, the amount of carbon emission reduction of HWP, can be effectively used as a basic data for promotion of wood utilization to revise and establish new wood utilization promotion policy such as ‘forest carbon offset scheme’, and ‘carbon storage labeling system of HWP’.

Organosolv pretreatment of <i>Liriodendron tulipifera</i> and simultaneous saccharification and fermentation for bioethanol production

Koo, Bon-Wook,Kim, Ho-Yong,Park, Nahyun,Lee, Soo-Min,Yeo, Hwanmyeong,Choi, In-Gyu Elsevier 2011 Biomass & bioenergy Vol.35 No.5

<P><B>Abstract</B></P><P>An acid-free organosolv process was proposed to overcome the problems caused by acid catalyst in organosolv process, thereby producing ethanol from <I>Liriodendron tulipifera</I> effectively. Although relative lignin contents were above 20%, enzymatic conversion increased significantly to 65% at all conditions, and thus correlation between lignin and enzymatic conversion could not be explained using relative lignin content. Enzymatic conversion increased significantly above 65% regardless of temperature, which suggests the organosolv pretreatment with sodium hydroxide can be performed at lower temperature. FE-SEM showed that the process made the structure loose and broke down biomass through lignin dissolution. Wrinkle formation by alkaline swelling was also observed and it might increase surface area. Although pore-volume increased slightly, it was not the sole key factor for the organosolv pretreatment with sodium hydroxide. Increase in surface area and enzyme adsorption enhanced the enzymatic hydrolysis. Ethanol of 96% could be produced theoretically and it suggested that the acid-free organosolv process was an effective pretreatment method for bioethanol production from <I>L. tulipifera</I>.</P> <P><B>Highlights</B></P><P>► An acid-free organosolv pretreatment using an alkaline catalyst. ► Enhancement in enzymatic hydrolysis through increase in surface area and enzyme adsorption. ► Theoretical ethanol production yield of 96% from <I>Liriodendron tulipifera</I> using the organosolv pretreatment with sodium hydroxide.</P>

열처리가 목재의 내후성에 미치는 영향 평가

박용건 ( Yonggun Park ),윤새민 ( Sae-min Yoon ),여환명 ( Hwanmyeong Yeo ),황원중 ( Won-joung Hwang ) 한국목재공학회 2021 한국목재공학회 학술발표논문집 Vol.2021 No.2

목재 열처리는 160~260℃ 범위 온도로 처리하여 목재의 성질을 변화시키는 방법을 말한다. 열처리에 의해 목재는 세포벽을 구성하는 주요 성분이 열가수분해(thermal hydrolysis)되면서 목재의 물리ㆍ역학적 성질이 영구적으로 변하는 것으로 알려져 있으며, 수종이나 열처리 온도와 시간, 열처리에 사용된 열전달 매개체의 종류 등에 따라서 그 정도는 다르게 나타나는 것으로 알려져 있다. 본 연구에서는 열처리 온도와 열처리 시간이 목재의 부후균에 대한 저항성에 미치는 영향을 조사하였다. 이를 위해 190℃와 220℃의 온도 조건에서 열처리 시간을 달리한 일본잎갈나무(Larix kaempferi )재에 대한 갈색부후균(부후개떡버섯균, Fomitopsis palustris)과 백색부후균(구름버섯균, Trametes versicolor )에 의한 질량 감소율을 평가하였다. 균의 종류에 따라 정도의 차이는 있었지만, 두 균류 모두 열처리 온도가 높을수록 열처리 시간이 길수록 질량 감소율이 작아지는 것을 확인하였다. 이는 고온의 열처리에 의해 목재 세포 벽의 주요 성분의 열분해되면서 소수성이 증가하게 되고, 세포벽 구성성분의 화학적 변화에 의해 부후 균의 생장 환경에 부정적인 영향을 미치기 때문으로 생각된다. 다만, 이를 입증하기 위한 추가 연구가 필요할 것이다.

지름 또는 대각 길이 45cm 크기 국산 소나무 특대재의 천연건조 특성 연구

이창진 ( Changjin Lee ),이남호 ( Namho Lee ),오승원 ( Seung-won Oh ),여환명 ( Hwanmyeong Yeo ),이태경 ( Taekyeong Lee ),바트-오츠랄 ( Batjargal Bat-uchral ),조명식 ( Myungsik Cho ) 한국목재공학회 2023 한국목재공학회 학술발표논문집 Vol.2023 No.1