• Elastomers and Composites
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• 제51권3호
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• pp.195-205
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• 2016

A series of aromatic poly(hydroxyamide)s (PHAs) containing varying oligo(oxyethylene) substituents and 1,3-phenylene imide ring unit in the main chain were synthesized by the direct polycondensation reaction. The inherent viscosities of the PHAs exhibited in the range of 0.89~1.12 dL/g in DMAc or DMAc/LiCl solution. The PH-2~5 copolymers were easily soluble in strong aprotic solvents: DMAc, NMP, DMSO etc. and the PH-5 copolymer was soluble in less polar solvents such as m-creasol and pyridine with LiCl salt on heating. However, all PBOs were quite insoluble in other solvents, but only partially soluble in sulfuric acid. All copolymers (PH-2~5) could afford the flexible and tough films by solution casting. We identified that the PHAs were converted to the PBOs by the thermal cyclization reaction in the range of $200{\sim}380^{\circ}C$. The 10% weight loss temperatures and char yields of the PBOs were recorded in the range of $382{\sim}647^{\circ}C$ and 38.7~73.1% values at $900^{\circ}C$. The tensile strength and initial modulus of the PH-5 in the copolmers showed the highest values of 2.46 GPa and 49.55 MPa, respectively. The LOI values of the PHAs were in the range 26.6~29.0%, and increased with increasing 1,3-phenylene imide ring unit.

• Journal of the Korean Wood Science and Technology
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• 제40권6호
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• pp.445-453
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• 2012

본 연구에서는 백합나무의 급속 열분해 공정에서 시료의 입자크기 및 함수율 조건이 열분해 산물(가스, 바이오오일, 바이오촤)의 수율과 물리 화학적 특성에 미치는 영향을 구명하였다. 시료의 함수율이 낮을수록 바이오오일의 수율은 증가하였으며 시료의 입자 크기는 수율 변화에 큰 영향을 미치지 않았다. 각 조건별로 생성된 바이오오일은 20~30%의 수분 함량과 pH 2.2~2.4, 발열량 16.6~18.5 MJ/kg의 수준을 나타내었으며 바이오오일 내 수분 함량은 높은 함수율 시료 조건에서 증가하는 것을 확인하였다. 바이오촤의 경우 80% 이상이 탄소로 이루어져있으며 발열량은 26.2~30.1 MJ/kg 수준으로 측정되었다.

• 자원리싸이클링
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• 제15권1호
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• pp.3-11
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• 2006

유동층 열분해로에서 상수리나무의 급속열분해를 수행하고 생성된 바이오오일의 물리화학적 특성을 GC/MS를 이용하여 분석하였다. 유동층 열분해로에서 얻어진 상수리나무와 낙엽송의 바이오오일 수율은 각각 $350^{\circ}C,\;400^{\circ}C$에서 최대치를 보였으며 이는 두 수종간의 셀룰로오스 함량차이에 기인하는 것으로 추정된다. 최적온도 이상에서는 반응온도가 증가할수록 프리보드에서의 2차 열분해에 의하여 촤와 오일의 수율이 감소하였고 가스상 성분과 수분의 함량이 증가하였다. 유등층 열분해로에서 시료의 투입량은 생성물의 수율과 조성에는 큰 영향을 주지 않았으며 이는 충분한 혼합이 이루어지기 때문으로 판단되었다.

• 공업화학
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• 제32권2호
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• pp.205-213
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• 2021

The present study aimed to determine the effect of co-pyrolysis of sawdust biomass and scrap tyre waste employing different blending ratios of sawdust to waste tyre such as 100:0, 75:25, 50:50, 25:75, and 0:100. The thermochemical characterization of feedstocks was carried out by employing the proximate, ultimate analysis, and thermogravimetric (TGA) analyses, calorific values, and scanning electron microscope coupled with energy dispersive x-ray analysis (SEM-EDX) to select the blending ratio having better bioenergy potential amongst the studied ratios. The blending ratio of 25:75 (sawdust to waste tyre) was selected for the co-pyrolysis study in a fixed-bed pyrolysis reactor system based on its solid biofuels properties such as heating value (30.18 MJ/kg), and carbon (71.81 wt%) and volatile matter (63.82 wt%) contents. The pyrolysis temperatures were varied as 500, 600 and 700 ℃ while the other parameters such as heating rate and nitrogen flowrate were maintained at 30 ℃/min and 0.5 L/min respectively. The bio-oil yields as 31.9, 47.1 and 61.2 wt%, bio-char yields as 34.5, 34.2 and 31.4 wt% and gaseous product yields as 33.6, 18.60 and 7.3 wt% at the pyrolysis temperatures of 500, 600 and 700 ℃ respectively were obtained. The blends of sawdust and waste tyres showed the improved energy characteristics which could provide the solution for the beneficial management of sawdust and scrape tyre wastes via co-pyrolysis processing.

• Environmental Engineering Research
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• 제23권2호
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• pp.121-128
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• 2018

This paper describes the non-isothermal pyrolysis of cashew shell cake (CSC) - bituminous coal blends. The blends exhibit two distinct stages in the thermogravimetric curves, which the first stage stems from CSC and the second one from the superposition of CSC and coal pyrolysis. The pyrolysis behavior of the blend was linearly proportional to the blending ratios. The overall behavior of the blends was evaluated in terms of the maximum rate of weight loss, characteristic temperatures, char yields, and the calculated and experimental thermogravimetric curves. The activation energies ranged up to 49 kJ/mol for the blends were obtained and used to evaluate the interaction in the blends. The present thermogravimetric study shows that there is no significant interaction between CSC and coal in the blends, and it was supported by the characteristic values which are linearly proportional to the weight percentages of cashew cake-shell in the blends. The no-interaction might be due to the fact that the main reaction zones are distinctively different for two constituents, so the additive rule is acceptable for describing pyrolysis behavior of the present blends.

• Environmental Engineering Research
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• 제22권3호
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• pp.320-328
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• 2017

This paper describes the non-isothermal pyrolysis of wood pellet and saw dust, and their blends with bituminous coal. The blends showed the distinct, two peaks in thermogravimetric curves, and the first peak came from the biomass pyrolysis and the second one came from the coal pyrolysis. The interaction in the blend was evaluated in terms of the maximum rate of weight loss, characteristic temperatures, char yields, and the calculated and experimental thermogravimetric curves. The activation energies and frequency factors for the blends were obtained with the multi-stage, Coats and Redfern method. The respective activation energies of 73 and 67 kJ/mol and the frequency factors of 725,100 and $65,262min^{-1}$ were obtained for the present wood pellet and saw dust samples. The thermogravimetric study shows that there is no significant interaction between the present biomass and coal in the blends, and the pyrolysis behavior can be described with the additive rule.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 추계학술대회 초록집
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• pp.107-107
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• 2010

Hydrogen is an alternative fuel for the future energy which can reduce pollutants and greenhouse gases. Synthesis gas have played an important role of synthesizing the valuable chemical compound, for example methanol, DME and GTL chemicals. Renewable biomass feedstocks can be potentially used for fuels and chemical production. Current thermal processing techniques such as fast pyrolysis, slow pyrolysis, and gasification tend to generate products with a large slate of compounds. Lignocellulose feedstocks such as forest residues are promising for the production of bio-oil and synthesis gas. Pyrolysis and gasification was investigated using thermogravimetric analyzer (TGA) and bubbling fluidized bed gasification reactor to utilize forest woody biomass. Most of the materials decomposed between $320^{\circ}C$ and $380^{\circ}C$ at heating rates of $5{\sim}20^{\circ}C/min$ in thermogravimetric analysis. Bubbling fluidized bed reactor were use to study gasification characteristics, and the effects of reaction temperature, residence time and feedstocks on gas yields and selectivities were investigated. With increasing temperature from $750^{\circ}C$ to $850^{\circ}C$, the yield of char decreased, whereas the yield of gas increased. The gaseous products consisted of mostly CO, CO2, H2 and a small fraction of C1-C4 hydrocarbons.

• 한국수소및신에너지학회논문집
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• 제21권6호
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• pp.587-594
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• 2010

Hydrogen is an alternative fuel for the future energy which can reduce pollutants and greenhouse gases. Synthesis gas has played an important role of synthesizing the valuable chemical compounds, for example methanol, DME and GTL chemicals. Renewable biomass feedstocks can be potentially used for fuel and chemicals. Current thermal processing techniques such as fast pyrolysis, slow pyrolysis, and gasification tend to generate products with a large slate of compounds. Lignocellulose feedstocks such as forest residues are promising for the production of bio-oil and synthesis gas. Pyrolysis and gasification was investigated using thermogravimetric analyzer (TGA) and bubbling fluidized bed gasification reactor to utilize forest woody biomass. Most of the materials decomposed between $320^{\circ}C$ and $380^{\circ}C$ at heating rates of $5{\sim}20^{\circ}C$/min in thermogravimetric analysis. Bubbling fluidized bed reactor was used to study gasification characteristics, and the effects of reaction temperature, residence time and feedstocks on gas yields and selectivities were investigated. With increasing temperature from $750^{\circ}C$ to $850^{\circ}C$, the yield of char decreased, whereas the yield of gas increased. The gaseous products consisted of mostly CO, $CO_2$, $H_2$ and a small fraction of $C_1-C_4$ hydrocarbons.

• 한국산학기술학회논문지
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• 제14권5호
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• pp.2550-2558
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• 2013

주사슬에 oligo(oxy ethylene) 팬던트를 갖는 poly(o-hydroxyamides)(PHAs) 공중합체를 저온에서 용액 중축합 반응에 의해서 합성하였다. 이들 공중합 전구체들의 특성은 1H-NMR, FT-IR, DSC, TGA, UTM 그리고 LOI 등을 이용하여 조사하였다. $35^{\circ}C$의 DMAc 또는 DMAc/LiCl 용액하에서 측정된 PHAs의 고유점성도는 0.74~1.42 dL/g의 범위를 보였다. 전구체들의 용해도는 oligo(oxy ethylene) 단위의 증가와 함께 증가하였으나, polybenzexazoles(PBOs)는 다양한 용매에도 거의 용해되지 않았다. 공중합 전구체들의 분해온도는 질소분위기하에서 $408{\sim}664^{\circ}C$의 범위를 보였고, $900^{\circ}C$에서 char 수득률은 13~59%의 값을 보였다. 공중합 전구체들의 기계적 성질과 난연특성은 oligo(oxy ethylene) 단위가 증가함에 따라 감소하였다.

• Korean Chemical Engineering Research
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• 제50권6호
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• pp.1034-1042
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• 2012

본 연구에서는 다양한 석탄 연구에 적용되고 있는 층류 반응기(LFR)를 이용하여 열분해와 연소 분위기에서 탄종에 따른 화염형상을 분석하였고, 휘발분 함량이 다른 두 석탄의 타르와 수트의 발생률을 구하였으며 이를 촤 입자의 표면적 및 표면 형상 변화와 함께 비교하였다. 본 연구에서 사용된 층류 반응기는 화염형상을 가시적으로 분석하기에 뛰어나므로 석탄이 반응할 때 생성되는 수트 클라우드를 측정하여 그 형상 변화를 근거로 탈휘발의 종료 지점을 가정하였다. 휘발분 함량이 많은 Berau 탄은 Glencore A.P. 탄보다 수트 클라우드의 폭과 길이가 증가하였고, 연소 분위기에서는 촤와 수트의 산화반응에 의하여 열분해 때보다 화염과 수트 클라우드의 길이가 짧아지면서 더 밝은 빛을 내었다. 포집높이 50 mm까지에서는 휘발분 함량이 많은 Berau 탄의 타르와 수트 발생률이 Glencore A.P. 탄보다 작았다. 이는 석탄 연료의 조성 중 Berau 탄내에 상대적으로 높은 산소 성분의 함량과 OH- 같은 라디칼들로 인해 타르가 산화되기 때문이다. 반면에, 50 mm 이후부터는 Berau 탄이 Glencore A.P. 탄보다 더 많은 타르와 수트의 발생률이 나타나며 탄종간에 수트 발생률의 역전현상이 일어나는데 이는 촤 입자 내부의 휘발물질과 탈휘발 과정에서 생성된 화염 속의 잔여 타르 및 light gas 성분이 반응하여 수트를 발생시켰기 때문이다. 이를 통해서 석탄 내의 휘발분의 함량과 산소농도는 수트 클라우드의 길이와 폭에 명확한 영향을 주며, 수트 발생률에 매우 중요한 인자라는 것을 확인할 수 있었다. SEM과 B.E.T.의 결과로부터 탈휘발이 종료된 후에도 촤 입자 내부의 잔존 휘발물들이 분출되면서 타르와 수트가 발생함을 확인할 수 있었고, 각 탄의 휘발분 함량과 기공의 발달 차이를 통해서 100 mm 이후에 나타난 타르와 수트의 발생률 역전 현상을 설명할 수 있었다.