• 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.

• 한국축산시설환경학회지
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• 제11권2호
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• pp.97-102
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• 2005

Anaerobic decomposition is one of the most common processes in nature and has been extensively used in waste and wastewater treatment for several centuries. New applications and system modifications continue to be adapted making the process either more effective, less expensive, or suited to the particular waste in question and the operation to which it is to be applied. Animal manure is a highly biodegradable organic material and will naturally undergo anaerobic fermentation, resulting in release of noxious odors, such as in manure storage pits. Depending on the presence or absence of oxygen in the manure, biological treatment process may be either aerobic or anaerobic. Under anaerobic conditions, bacteria carry on fermentative metabolisms to break down the complex organic substances into simpler organic acids and then convert them to ultimately formed methane and carbon dioxide. Anaerobic biological systems for animal manure treatment include anaerobic lagoons and anaerobic digesters. Methane and carbon dioxide are the principal end products of controlled anaerobic digestion. These two gases are collectively called biogas. The biogas contains $60\~70\%$ methane and can be used directly as a fuel for heating or electrical power generation. Trace amounts of ammonia and hydrogen sulfide ($100\~300\;ppm$) are always present in the biogas stream. Anaerobic lagoons have found widespread application in the treatment of animal manure because of their low initial costs, ease of operation and convenience of loading by gravity flow from the animal buildings. The main disadvantage is the release of odors from the open surfaces of the lagoons, especially during the spring warm-up or if the lagoons are overloaded. However, if the lagoons are covered and gases are collected, the odor problems can be solved and the methane collected can be used as a fuel. Anaerobic digesters are air-tight, enclosed vessels and are used to digest manure in a well-controlled environment, thus resulting in higher digestion rates and smaller space requirements than anaerobic lagoons. Anaerobic digesters are usually heated and mixed to maximize treatment efficiency and biogas production. The objective of this work was to review a current anaerobic biological treatment of animal manure for effective new technologies in the future.

• 에너지공학
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• 제15권1호
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• pp.45-51
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• 2006

본 연구에서는 LFG와 LNG의 혼합연료의 연소가스측 열전달 특성을 LFG, LNG 단독 연료와 비교함으로써 실험적으로 연구하였다. 실험을 위하여 파일럿 연소시스템을 제작하였으며, 연소시스템의 열교환부에는 수직 수평 배플을 가지는 다관형 열교환기를 설치하였다. 실험은 연료 주입 방식, 저위발열량, 메탄의 조성(44.5%, 54.5%)의 서로 다른 조건에서 수행되었다. 본 연구를 통하여 동일한 레이놀즈 수에서 LNG의 연소가스측누셀트 수는 LFG보다 큼을 알 수 있었으며, LFG의 경우에 LFG와 LNG 혼합 연료가 LFC 단독 연료보다 큼을 확인하였다. 따라서, LFG를 사용하는 경우 LFG 단독 연료를 사용하기보다는 LFG에 LNG를 적절히 첨가시켜 사용하는 것이 열전달이 향상되며, 발생 LFG의 공급 불안정성을 완화하는데 기여할 수 있다고 판단된다.

• 한국대기환경학회지
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• 제3권2호
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• pp.18-26
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• 1987

In order to investigate the character of air pollution by heavy metals and to elucidate the possible sources in Seoul city, this study was performed to measure the concentrations of heavy metals of total suspended particulate and air pollutants such as $SO_2, NO_2, CO, CH_4$, Non-methane hydrocarbon, ozone at the residential-traffic area (shinchon dong) in January and February, 1986. The results are as follows: 1. $SO_2$ and TSP concentration were 135ppb and 167 $\mug/m^3$ in average, respectively. 2. While concentrations of heavy metals such as Fe, Cu, Pb in the ambient air seems gradually decreasing annually, Ni compound has been shown the tendency of increasing. 3. Among heavy metals in TSP analysed, the iron was detected at the highest level, 0.905% and the cadimium was the lowest 0.004% in average, respectively. 4. V, Fe and Zn compounds in air were observed to be highly correlated with their correlation coefficients(r) higher than 0.7. Pb compound was highly correlated to the levels of Zn and Fe, however relatively less correlated to V compound. 5. Among concentrations of heavy metals in the particulates, V and Ni compounds were highly correlated with coefficient(r) of 0.8587; the cause might be imagined by the fact of releasing from combustion of fuel oil. Fe, Pb and Zn compounds were highly correlated $SO_2$ concentration. It might be explained that they were released by combustion of coal. 6. The level of $SO_2$ was highly correlated to most of heavy metals: especially correlation coefficient(r) to Pb compound was 0.9081. Pb compound was also highly correlated to NO, CO and TSP. TSP showed higher correlation to Pb and Cd compounds than to V and Ni compounds. It might be assumed that particulate was mainly produced by combusting coal from space heating and by exhausting gasoline and diesel oil from transportation rather than by burning fuel oil.

• Journal of the Korean Wood Science and Technology
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• 제42권4호
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• pp.439-449
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• 2014

2012년 신재생에너지공급의무화제도 시행으로 국내 목재펠릿 수요가 급증하고 있으나, 현재 우리나라의 목재펠릿 자급률은 10% 수준에 머물러, 급증하는 수요를 충족하기 어려울 것으로 예상된다. 따라서 안정적인 공급과 가격이 보장될 수 있는 새로운 바이오매스의 발굴을 통하여 목재펠릿에 대한 폭발적인 수요를 대체하는 일은 우리뿐만 아니라 세계적으로 시급한 과제라 할 수 있다. 본 연구의 분석결과 고체 팜 바이오매스 중 대표적인 EFB (empty fruit bunch)와 MF (mesocarp fiber)의 2012년도 연간 발생량(함수율 10% 기준)이 말레이시아와 인도네시아에서 각각 약 2,800만톤과 2,000만 톤으로, 두 지역에서만 연간 총 4,800만 톤이 발생되는 것으로 추정된다. 연료적 특성에 있어서도 EFB의 발열량이 목재의 90% 수준을 상회하므로 목재펠릿을 대체할 수 있는 우수한 바이오매스 에너지자원이라 할 수 있다. 다만, 높은 회분함량으로 인하여 주택이나 온실의 난방용으로는 부적합하지만 발전용이나 산업용으로는 충분히 사용가능할 것으로 판단된다.

• The Korean Journal of Ecology
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• 제18권3호
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• pp.333-340
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• 1995

This study aims to examine how the amount of sample and changes in combustible temperature of living branches and leaves treated with high temperature are associated with combustible time of two coniferous trees, Pinus rigida (R) and Larix leptolepis (L), which are the main victims of forest fire. During the first thirty minutes at $80^{\circ}C$, moisture content of R was higher than that of L by 12%, but after four hours, the moisture content was both lowered by 4~5% and turned to highly combustible leaves. With living leaves, the maximal combustible temperature, regardless of heating temperature, turned out to be higher than normal temperature by $67~140^{\circ}C$, and that with living branches, it was higher by $113~207^{\circ}C$. Also, with living leaves (R, L), the duration time of combustion was as follows: 605, 906 seconds at $400^{\circ}C$ and 76, 227 seconds at $600^{\circ}C$, respectively. Concerning the relation between the amount of burnt fuel and maximal temperature, the more the former was, the higher the latter. The total amounts of combustion heat of living branches and living leaves were 1, 121 Cal (20.8%) and 1, 137 Cal (21.4%), respectively. The total amount of combustion heat increased in proportion to the amount of consumed fuel: 100 g of living leaves and branches gave rise to 128 Cal, whereas 300 g did 556 Cal, that was more than three times.

• 한국연소학회지
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• 제22권4호
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• pp.19-26
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• 2017

This study investigates the gasification of coal char by $CO_2$ under high pressures in a drop tube furnace(DTF). The rate constants are derived for the shrinking core model using the conventional method based on the set reactor conditions. The computational fluid dynamic(CFD) simulations adopting the rate constants revealed that the carbon conversion was much slower than the experimental results, especially under high temperature and high partial pressure of reactants. Three reasons were identified for the discrepancy: i) shorter reaction time because of the entry region for heating, ii) lower particle temperature by the endothermic reaction, and iii) lower partial pressure of $CO_2$ by its consumption. Therefore, the rate constants were corrected based on the actual reaction conditions of the char. The CFD results updated using the corrected rate constants well matched with the measured values. Such correction of reaction conditions in a DTF is essential in deriving rate constants for any char conversion models by $H_2O$ and $O_2$ as well as $CO_2$.

• 대한환경공학회지
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• 제32권11호
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• pp.1046-1053
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• 2010

본 연구의 목적은 생활폐기물에 저품위 무연탄의 혼합 후 열분해 반응 특성을 연구하는데 목적이 있다. 반응 변수로 혼합율, 반응온도, 승온속도에 따른 열분해조건을 고찰하였다. 그 결과, 저품위 무연탄 20 wt.%를 첨가한 혼합 시료가 3,500 kcal/kg 이상의 저위발열량 확보를 위한 최적의 혼합비로 나타났다. 가장 높은 반응속도상수 도출을 위해서는 $700^{\circ}C$의 조건에서 이루어 질 것으로 판단되었다. 또한 시간당 온도의 비가 증가할수록 반응속도상수가 선형적으로 높게 나타났으나, 열분해 시 전력비 상승 및 열분해 생성 char의 수율 등을 고려하여 더 낮은 승온속도에서 열분해가 이루어져야 할 것으로 판단된다.

• Bulletin of the Korean Chemical Society
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• 제34권10호
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• pp.3065-3072
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• 2013

Direct synthesis of $H_2O_2$ and in situ oxidative desulfurization of model fuel over Au/Ti-HMS and Au/TS-1 catalysts has been comparatively investigated in water or methanol. Maximum amount (82%) of active $Au^0$ species for $H_2O_2$ synthesis was obtained. Au/Ti-HMS and Au/TS-1 exhibited the contrary performances in $H_2O_2$ synthesis as $CH_3OH/H_2O$ ratio of solvent changed. $H_2O_2$ decomposition and hydrogenation in water was inhibited by the introduction of methanol. Effect of $O_2/H_2$ ratio on $H_2O_2$ concentration, $H_2$ conversion and $H_2O_2$ selectivity revealed a relationship between $H_2O_2$ generation and $H_2$ consumption. The highest dibenzothiophene removal rate (83.2%) was obtained over Au/Ti-HMS in methanol at 1.5 of $O_2/H_2$ ratio and $60^{\circ}C$. But removal of thiophene over Au/TS-1 should be performed in water without heating to obtain a high removal rate (61.3%). Meanwhile, $H_2$ conversion and oxidative desulfurization selectivity of $H_2$ were presented.

• 청정기술
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• 제14권2호
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• pp.117-122
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• 2008

중발열량 석탄 합성가스의 연소 및 NOx 발생 특성에 대한 이론적 해석을 수행하였다. 석탄 합성가스는 CO, $H_2,\;CO_2,\;N_2$가 주성분이고, 미량의 $CH_4$ 및 $NH_3$를 함유하는 것으로 가정하였다. 열화학적 해석을 통해 합성가스 연소 시의 화염 온도, 배기가스의 주요 및 부차적 화학종들의 조성, 열 및 연료 NOx 발생량을 계산하였다. 또한 합성가스 중의 $CH_4$ 및 $NH_3$ 성분이 연소 및 NOx 발생에 미치는 영향을 검토하였다. 본 석탄 합성가스들의 계산결과들을 토대로 가스터빈 연소기의 NOx 저감 설계에 필요한 기본 방향과 기준을 제시하였다.