• Journal of the Korean Wood Science and Technology
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• 제38권2호
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• pp.149-158
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• 2010

Organosolv pretreatments which utilized sulfuric acid, sodium hydroxide and ammonia as catalysts were conducted to screen the effective catalyst for organosolv pretreatment of Liriodendron tulipifera. The enzymatic hydrolysis was achieved effectively with sulfuric acid (74.2%) and sodium hydroxide (63.7%). They were thus considered as effective catalysts for organosolv pretreatment of L. tulipifera. The organosolv pretreatments with sulfuric acid and sodium hydroxide showed a different behavior on the reaction mechanism. The pretreatment with sulfuric acid increased the biomass roughness and pore numbers. On the other hand, the pretreatment with sodium hydroxide enhanced the surface area due to the size reduction and minor defiberization which were caused by hemicellulose degradation at an initial stage and more defiberization by lignin degradation at a later stage. The organosolv pretreatment with sodium hydroxide was performed at several different conditions to evaluate effectiveness of sodium hydroxide as a catalyst for organosolv pretreatment. According to the results of enzymatic digestibility, the changes of chemical composition and the morphological analysis of pretreated biomass, it was suggested that the pretreatment time impacted primarily on enzymatic hydrolysis. Increase in surface area during the pretreatment was a major cause for improvement in enzymatic digestibility when sodium hydroxide was used as a catalyst.

• Korean Chemical Engineering Research
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• 제54권4호
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• pp.448-452
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• 2016

새로운 수송용 에너지자원으로 각광받는 바이오매스의 효율적인 당화를 위한 전처리방법이 연구되고 있다. 최근 바이오매스의 에너지 전환 공정 중 전처리 비용이 높은 비중을 차지하고 있으며 이중 폐수처리가 커다란 문제점으로 지적되고 있다. 따라서 폐수발생을 줄이고 재사용이 용이한 유기용매(Organosolv)를 이용한 전처리를 수행하였으며, 전처리 바이오매스의 잔류 고형물의 양과 제거된 성분의 양을 이용하여 바이오매스의 전처리 효과를 효소당화를 통해 알아보았다. 전처리에 사용한 유기용매로는 99.5 wt% 에탄올을 사용하였고, 초본계 바이오매스인 옥수수대(corn stover)를 이용하여 전처리 하였다. 전처리 효과는 $130{\sim}190^{\circ}C$ 조건에서 시간대별로 진행하여 전처리된 바이오매스의 효소당화를 통하여 확인하였다. 효소당화결과로 가장 높은 글루코오스 당화율을 보였던 전처리 온도는 $190^{\circ}C$에서 반응시간 70분 이상의 조건 이였으며, 이 때 68% 이상의 당화율을 얻을 수 있었다. 또한 전처리 바이오매스의 잔류 고형물(Solid remaining)은 70% 이상이었고, 대부분의 셀룰로오스(Cellulose)와 헤미셀룰로오스(Hemicellulose)의 손실이 미비하여 대부분의 당 성분을 회수할 수 있다는 장점을 보였다.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2009년도 추계학술대회 논문집
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• pp.520-520
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• 2009

Organic by-products derived from cellulose and lignin during organosolv pretreatments of yellow poplar wood (Liriodendron tulipifera) in the presence of $H_2SO_4$ and NaOH as catalysts, respectively, were subjected to various analyses to elucidate their effects on further performance of biological ethanol fermentation and provide preliminary data for the structure and utilization of organosolv lignin. Monomeric sugars amounted to ca. 2.2-7.7% in the organosoluble fraction of the organosolv pretreatment with $H_2SO_4$, while significantly low amount of sugars (0.2-0.3%) were determined in that of the organosolv pretreatment with NaOH. In case of addition of $H_2SO_4$ during organosolv pretreatment of biomass, a fermentation of the organosoluble fraction could be considered as an essential process to increase an efficiency of biomass utilization as well as yield of bioethanol. Precipitates, insoluble by-products in the solvent mixture, were also cficiency oed by diverse analytical methods and revealed that these were typically composed of a lignin moiety regardless of catalyst. According to the results of nuclear magnetic resonance (NMR), Fourier Tcinsform Infrared Spectroscopy (FT-IR) and Gel permeation chromatograp r (GPC), the main components of precipitates seem to be lignin polymers. However, their structures could be slightly modified during pretreatment and mixed with some carbohydrates by chemical bonds and/or physical associations.

• 펄프종이기술
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• 제47권4호
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• pp.21-29
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• 2015

In this study, the feasibility of utilizing wood chips from pitch pine (Pinus rigida) was evaluated for bioethanol production by an organosolv pretreatment and enzymatic saccharification. When wood chips from pitch wood were pretreated with 75% (v/v) ethanol and 1.7% sulfuric acid as a catalyst at H-factor 2000, average pulp yield was 43.3%, which pretreated wood fibers showed higher glucan (55.8%) and lower lignin (12.2%) contents than untreated control (43.9% glucan and 27.8% lignin). After enzymatic saccharification, the organosolv pulps with 56.2% delignification rate reached above 97% conversion rate of cellulose to glucose. These results indicated that increasing the delignification rate causes micro pores on the surface of organosolv pulps resulting in improved the accessibility of enzyme onto the substrate. Moreover, it was in agreement with the SEM examination of wood fibers.

• Journal of the Korean Wood Science and Technology
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• 제43권5호
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• pp.578-590
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• 2015

The present study examines the influence of slurry composting and biofiltration liquid fertilizer (SCBLF) treatment on the biomass characteristics of yellow poplar, and the optimization of organosolv pretreatment for sugar production. After SCBLF treatment, total exchangeable cation contents of yellow poplar was increased from $3.1g\;kg^{-1}$ to $4.4g\;kg^{-1}$, and as a result, biomass production of yellow poplar was also enhanced by 82.3%. Organosolv pretreatment was conducted with three independent variables: 1) reaction temperature: $133.2^{\circ}C$ to $166.8^{\circ}C$; 2) acid concentration: 0.2% to 1.8%; and 3) reaction time: 1.6 min to 18.4 min. Reaction temperature was the most significant variable in water insoluble solid (WIS) recovery rate. High overall sugar yield was attained from pretreatment conditions approximately 50% of WIS recovery rate, and the highest overall glucose yield (44.0%) was achieved from pretreatment at $140^{\circ}C$ with 1.5% acid concentration for 5 min. Consequently, 21.1% of glucose and 5.8% of xylose were produced from the organosolv pretreatment of SCBLF-treated 8-year-old yellow poplar.

• Journal of the Korean Wood Science and Technology
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• 제46권6호
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• pp.637-644
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• 2018

The air permeability of yellow poplar log cross section before and after organosolv pretreatment was investigated, and the moisture absorption of control and organosolv pretreated rectangular parallelepiped specimens was investigated in this study. It was revealed that the diameters of through pores were enlarged and the number of bigger pore was increased by the organosolv pretreatment. The air permeabilities of the cross sections of yellow poplar log were changed from 1.61 darcy to 23.30 darcy, but their weights were reduced by 5 percent. The equilibrium moisture content of control wood specimen at the exposed relative humidity were 5.9 % at 32 %, 9.7 % at 58 %, 14.8 % at 80.5 %, 19.7 % at 90 %, 25.7 % at 95 % and 29.9 % at 100%. The equilibrium moisture content of the specimens pretreated with the parameter of sulfuric acid catalyst of 0.5 % (w/w) were 19.5 % at 32 %, 29.3 % at 58 %, 39.6 % at 80.5 %, 59 % at 90 %, 111.3 % at 95 % and 111.3 % at 100 %, while those pretreated with the parameter of sulfuric acid catalyst of 1.0 % (w/w) were 17.4 % at 32 %, 23.9 % at 58 %, 27.7 % at 80.5 %, 40.6 % at 90 %, 68.8 % at 95 % and 110.0 % at 100 %. The moisture absorption of organosolv pretreated rectangular parallelepiped specimens was higher than that of control specimen.

• Journal of the Korean Wood Science and Technology
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• 제52권2호
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• pp.101-117
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• 2024

The conversion characteristics of the major components of Liriodendron tulipifera were investigated during acid-catalyzed organosolv pretreatment. Glucan in L. tulipifera was slowly hydrolyzed, whereas xylan was rapidly hydrolyzed. Simultaneous hydrolysis and degradation of xylan and lignin occurred; however, after complete hydrolysis of xylan at higher temperatures, lignin remained and was not completely degraded or solubilized. These conversion characteristics influence the structural properties of glucan in L. tulipifera. Critical hydrolysis of the crystalline regions in glucan occurred along with rapid hydrolysis of the amorphous regions in xylan and lignin. Breakdown of internal lignin and xylan bonds, along with solubilization of lignin, causes destruction of the lignin-carbohydrate complex. Over a temperature of 160℃, the lignin that remained was coalesced, migrated, and re-deposited on the surface of pretreated solid residue, resulting in a drastic increase in the number and content of lignin droplets. From the results, the characteristic conversions of each constituent and the changes in the structural properties in L. tulipifera effectively improved enzymatic hydrolysis in the range of 140℃-150℃. Therefore, it can be concluded that significant changes in the biomass recalcitrance of L. tulipifera occurred during organosolv pretreatment.

• Korean Chemical Engineering Research
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• 제59권1호
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• pp.54-59
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• 2021

섬유소계 바이오매스는 전분질계 바이오매스에 비해 리그닌이 많아 전처리가 필수적으로 요구된다. 섬유소계 바이오매스를 전처리하기 위한 용매인 에탄올은 효소당화(enzymatic hydrolysis)에 저해가 되는 물질을 분별하기 쉬우며, 증류를 과정을 통해 쉽게 재사용이 가능하다. 침출식 전처리 공정은 반응기 내에서 연속적으로 성분을 분별하여 고-액 분리가 용이하며 향후 스케일업에서도 유리하다. 본 연구에서는 이러한 장점들을 활용하여 대표 섬유소계 바이오매스인 옥수수대(corn stover)로 전처리를 진행하였으며 해당 공정을 밀대(wheat straw)와 거대억새(miscanthus)에 적용하여 추가적인 바이오매스의 적용 가능성을 확인하였다.

• Korean Chemical Engineering Research
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• 제54권6호
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• pp.806-811
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• 2016

오르가노솔브를 이용한 전처리는 목질계 바이오매스의 주요성분을 분별하고 전처리 바이오매스의 효소당화를 효과적으로 유도할 수 있는 공정이다. 이에 사용되는 오르가노솔브는 증류와 재순환공정으로 쉽게 재사용이 가능하고 고형성분에서 리그닌을 화학적으로 분별시킬 수 있다는 장점이 있다. 경제적인 이유로서 낮은 분자량의 알코올(에탄올, 메탄올 등)이 사용되어 왔으며, 무기산(염산, 황산, 인산 등)이 촉매로 첨가되었을 경우 탈리그닌 효과 및 자일로스 성분의 수율을 증대시킬 수 있다. 본 연구에서는 오르가노솔브로는 에탄올을 사용하였고 소량의 황산 촉매를 첨가해 전처리를 수행하였다. 바이오매스는 침출식반응기에서 40~50 wt%의 에탄올을 이용해 20~60분 동안 $170{\sim}180^{\circ}C$에서 전처리가 되었다. 전처리를 마친 바이오매스에 대해서는 전처리 효과를 알아보기 위하여 72시간 동안 효소당화를 수행하였다. 그 결과 $180^{\circ}C$에서 50 wt% 에탄올을 이용한 리기다의 2단 전처리에서 당화율은 40.6%로 나타났지만 같은 조건에서의 1단 전처리에서는 55.4%로 가장 높게 나타나는 것을 보았을 때, 용매와 촉매를 균일하게 섞는 것이 전처리에 효과적이라는 것을 알 수 있었다.

• 대한환경공학회지
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• 제39권10호
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• pp.568-574
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• 2017

본 연구는 폐목재로부터 organosolv 공정을 이용해서 리그닌을 분리할 때 영향을 미치는 주요 3개의 반응조건(반응시간($X_1$), 산 촉매의 농도($X_2$) 및 반응온도($X_3$))을 리그닌 회수율(y) 기준으로 최적화하였다. 중심합성계획법(central composite design, CCD)에 따라 반응온도 $136.4-203.6^{\circ}C$, 산촉매 농도 0-2.5%, 반응시간 26.36-93.64 분의 범위를 가진 실험계획을 수행해서 2차 모델식 및 최적조건을 수립하였다. 2차 모델식은 $y=-79.89+0.91X_1+9.8X_2-2.54{\times}10^{-3}X_1{^2}-2.11X_2{^2}$와 같이 얻었으며, 결정계수(coefficient of determination, $R^2$) 값은 0.8531으로 10% 이내의 유의수준에서 유의성을 나타냈다. 2차 모델식에 따라 예측되는 최고 리그닌 회수율은 12.46 g/100 g of dry wood이며 이때 최적 반응 조건은 반응온도 $178.2^{\circ}C$, 산 촉매 농도 2.32%으로 나타났다. 폐목재 대상 organosolv 공정에서의 리그닌 수율은 반응온도보다는 산 촉매 농도의 영향이 더 크게 나타났으며 반응시간에 의한 영향은 없는 것으로 나타났다. 모델의 변동성 분석(analysis of variance, ANOVA)에 따르면 리그닌 수율(y)에 대한 모델식의 유의확률은 p<0.001로 높은 유의성을 보였다. 최적조건에서 모델의 재현성을 검증한 결과 모델식이 실제공정을 적절하게 모사한 것으로 나타났다.