• 에너지공학
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• 제8권4호
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• pp.560-566
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• 1999

가압 조건하에서의 석탄가스화 특성을 규명하기위해 , 온도 압력 , 산소/석탄비, 수증기/석탄비 등을 변화시켜가며 로토탄(sub A)에 대하여 PDTF(Pressuized drop tube furnace)실험을 수행하였다. 실험결과, 상압 조건에서보다 가압조건에서의 가스화가 탄소전환율과 냉가스효율의 측면에서 더 유리한 것으로 측정되었다. 최대의 냉가스효율을 보이는 산소/석탄비의 증가가 냉가스효율의 증가를 가져왔다. 압력이 증가할수록 열분해에 의한 탄소전환의 비중은 감소하고 대신 기고반응에 의한 탄소전환의 비중이 증가하였다.

• 한국에너지공학회:학술대회논문집
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• 한국에너지공학회 1999년도 춘계 학술발표회 논문집
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• pp.23-31
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• 1999

가압 조건하에서의 석탄가스화 특성을 규명하기 위해, 온도, 압력, 산소/석탄비, 수증기/석탄비 등을 변화시켜가며 로토탄(Sub A)에 대하여 PDTF(Pressurized drop tube furnace) 실험을 수행하였다. 실험결과, 상압 조건에서보다 가압조건에서의 가스화가 탄소 전환율과 냉가스효율의 측면에서 더 유리한 것으로 측정되었다. 최대의 냉가스효율을 보이는 산소/석탄비(무게기준)는 0.5∼0.7(g/g)로 측정되었고, 온도가 충분히 높은 경우에만 수증기/석탄비의 증가가 냉가스효율의 증가를 가져왔다. 압력이 증가할수록 열분해에 의한 탄소전환의 비중은 감소하고 대신 기고반응(heterogeneous reaction)에 의한 탄소전환의 비중이 증가하였다.

• 한국농공학회논문집
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• 제52권3호
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• pp.39-45
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• 2010

Quantification of carbon absorption and understanding the human induced land use changes (LUC) forms one of the major study with respect to global climatic changes. An attempt study has been made to quantify the carbon absorption by LUC through remote sensing technology. The Landsat imagery four time periods was classified with the hybrid classification method in order to quantify carbon absorption by LUC. Thereafter, for estimating the amount of carbon absorption, the stand biomass of forest was estimated with the total weight, which was the sum of individual tree weight. Individual tree volumes could be estimated with the crown width extracted from digital forest cover type map. In particular, the carbon conversion index and the ratio of the $CO_2$ molecular weight to the C atomic weight, reported in the IPCC guideline, was used to convert the stand biomass into the amount of carbon absorption. Total carbon absorption has been modeled by taking areal estimates of LUC of four time periods and carbon factors for land use type and standing biomass. Results of this study, through LUC suggests that over a period of construction, 7.10 % of forest and 9.43 % of barren were converted into urban. In the conversion process, there has been a loss of 6.66 t/ha/y (7.94 %) of carbon absorption from the study area.

• 한국응용과학기술학회지
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• 제21권1호
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• pp.45-50
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• 2004

The effects of reaction temperature and flow rate of reactants on the methane conversion, product selectivity, product ratio, and carbon deposition were investigated with 13wt% Ni/MgO catalyst. Reaction temperatures were changed from 600 to $850^{\circ}C$, and reactants flow rates were changed from 100 to 200 mL/mim. There were no significant changes in the methane conversion observed in the range of temperatures used. It is possibly stemmed from the nearly total exhaustion of oxygen introduced. The selectiveties of hydrogen and carbon monoxide did not largely depend on the reaction temperature. The selectivities of hydrogen and carbon monoxide were 96 and 90%, respectively. Carbon deposition observed was the smallest at $750^{\circ}C$ and the largest at $850^{\circ}C$. It is found that the proper reaction temperature is $750^{\circ}C$. The best reactant flow rate was 150 ml/min.

• 대한화학회지
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• 제15권2호
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• pp.55-63
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• 1971

In this study, several nickel catalysts for the steam-hydrocarbon reforming process were prepared from various nickel salt, magnesium oxide, alumina and kaolinite. The activity and strength of the catalysts were investigated. 1. The proper composition of the calcined catalysts are: NiO (5-15%)-MgO(10-20%)-$Al_2O_3$(10-40%)-Kaolinite(50-80%). 2. The admixed or cosedimented ingredients of the catalysts was pelletized and calcinated at 1000 or $1150^{\circ}C$. Calcination at $1150^{\circ}C$ for an hour was optimum. 3. The water to oil ratio (W/O) for reforming of hexane should be above 7 mole/mole. As the W/O increases, more carbon dioxide and hydrogen, but less carbon monoxide was produced. Also carbon deposition become lessen at higher W/O. 4. Maximum conversion had attained at about $850^{\circ}C$. As the reaction temperature increases, more carbon monoxide and hydrogen, but less carbon dioxide and lower hydrocarbon was produced. 5. The percent conversion at $850^{\circ}C$ was about 80%, using a catalyst which the nickel oxide content are 5%.

• Journal of Microbiology and Biotechnology
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• 제22권10호
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• pp.1406-1411
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• 2012

5,5'-Dithiobis(2-nitrobenzoic acid) (DTNB) was selected as an electron transfer mediator and was covalently immobilized onto high porosity carbon cloth to employ as a working electrode in an electrochemical $NAD^+$-regeneration process, which was coupled to an enzymatic reaction. The voltammetric behavior of DTNB attached to carbon cloth resembled that of DTNB in buffered aqueous solution, and the electrocatalytic anodic current grew continuously upon addition of NADH at different concentrations, indicating that DTNB is immobilized to carbon cloth effectively and the immobilized DTNB is active as a soluble one. The bioelectrocatalytic $NAD^+$ regeneration was coupled to the conversion of L-glutamate into ${\alpha}$-ketoglutarate by L-glutamate dehydrogenase within the same microreactor. The conversion at 3 mM monosodium glutamate was very rapid, up to 12 h, to result in 90%, and then slow up to 24 h, showing 94%, followed by slight decrease. Low conversion was shown when substrate concentration exceeding 4 mM was tested, suggesting that L-glutamate dehydrogenase is inhibited by ${\alpha}$-ketoglutarate. However, our electrochemical $NAD^+$ regeneration procedure looks advantageous over the enzymatic procedure using NADH oxidase, from the viewpoint of reaction time to completion.

• 한국수소및신에너지학회논문집
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• 제21권4호
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• pp.328-339
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• 2010

A new gasification model for coal char was developed considering the effects of pore structure and solid reaction product (ash) and compared with conventional models. Among various parameters reflecting microscopic pore structure, initial pore surface per unit volume of char was found to have the largest effect on carbon conversions. Reaction studies showed that the proposed model can predict carbon conversion more accurately over a broader range of reaction degree compared to the conventional models. Therefore the model proposed in this study would be useful for the design of pilot or commercial scale gasifiers.

• Korean Chemical Engineering Research
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• 제56권5호
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• pp.738-751
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• 2018

The effect of the reaction temperature and reaction time on the thermal oxidative purification quality of detonation nanodiamond (NDsoot) was investigated in a gas-solid fluidized bed reactor of a $0.10m-ID{\times}1.0m$-high stainless steel column with zirconia beads ($d_{SV}=99.2{\mu}m$). The carbon conversion increased with increasing the reaction temperature; however, when the reaction temperature was greater than 773 K, the carbon conversion did not increase. The content of $sp^3$-hybridized carbon at the reaction temperature of 703 K barely changed when the reaction time was more than 30 minutes, but at 773 K, the content decreased as preferred. At 703 K, the purification quality increased with the increasing reaction time; however, at 773 K, the purification quality increased up to 30 minutes and then decreased rapidly.

• 한국토양비료학회지
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• 제31권4호
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• pp.380-383
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• 1998

본 연구는 퇴비중의 유기물 함량으로부터 탄소함량을 구하기 위한 환산계수를 결정하기 위하여 수행하였다. 퇴비중의 유기물 함량은 회화법으로, 탄소함량은 원소 분석기를 사용하여 분석한 결과 유기물 함량과 탄소함량의 관계는 "탄소함량(%)=$1.995+0.484{\times}$유기물 함량(%)"의 직선 회귀식을 따랐고, 분산분석에 의한 회귀직선의 유의성 검정은 고도로 유의하게 나타났다(P < 0.001). 기존의 토양 유기물 환산계수 1.724나 1.8을 적용할 경우, 퇴비중의 유기물 함량으로부터 환산한 탄소함량은 실제보다 10% 이상 높게 평가되어 우리 나라에서 생산, 판매되는 퇴비의 탄소함량을 구할 때는 상기 회귀식을 적용하는 것이 타당하리라 생각된다.

• 대한토목학회논문집
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• 제43권1호
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• pp.63-69
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• 2023

'탄소중립 기술적용 시나리오 모형 (CATAS; Carbon-neutrality Assessment based on Technology Application Scenario)'은 공간 단위에서 에너지전환, 수송, 건물 등 분야에 탄소중립 기술을 적용했을 경우 온실가스 감축 효과성 분석을 제공한다. 모형의 개발범위는 온실가스 배출원은 온실가스 직접배출량 대상으로 분석하며, 공간적 범위는 직접·간접배출의 경계를 공간적 범위로 설정하였다. 그리고 기술적 범위는 2050 탄소중립 시나리오에서 온실가스 배출량이 가장 큰 전환부문의 9개 기술과 산림 흡수원을 포함하였다. 탄소중립률 평가 방법론은 ①온실가스 배출현황 분석, ②기술도입에 따른 에너지생산량 예측, ③온실가스 감축량 산정, ④탄소중립률 산정까지 4단계로 이루어져있다. 웹기반 CATAS-BASIC을 개발 한 후 서울시의 ｢2050 온실가스 감축추진계획｣상 제시된 신재생에너지 보급목표를 적용하여 분석을 실시하였다. 태양광·수소연료전지·수열을 적용한 결과, 서울시의 전환부문 배출량인 1.49백만 tCO₂eq 중 기술도입으로 0.43백만 tCO₂eq 감축하여 전환부문 탄소중립률은 28.94 %로 분석되었다.