• 한국수소및신에너지학회논문집
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• 제32권1호
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• pp.68-76
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• 2021

Climate change problems occur during the use of fossil fuel and the process of biogas production. Research continues to convert carbon dioxide and methane, the major causes of climate change, into high-quality energy sources. in order to present the performance potential for the novel plasma-recuperative burner reformer, the reforming characteristics for each variable were indentified. The optimal operating condition of was an O2/C ratio of 1.0 and a total gas supply of 20 L/min. At this time, CH4 conversion was 64%, H2 selectivity was 39%, and H2/CO ratio was 1.13, which were the results applicable to the solid oxide fuel cell fuel stack for RPG, or Residential Power Generator. Recirculation of reformed gas increases the amount of H2 and CO, which are combustible gases, especially the amount of H2. As a result, the H2 selectivity is improved, and high-quality gas can be produced.

• 한국환경보건학회지
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• 제37권4호
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• pp.315-322
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• 2011

Objectives: Organic matter and nitrogen were removed using the EGSB process, a high-rate anaerobic process, in combination with a nitritation-denitritation process, in order to ensure the stable treatment of seafood processing wastewater. Methods: The upflow velocity of an EGGS reactor was operated at 10 m/hr for maximal organics removal efficiency. For removal of nitrogen from seafood processing wastewater a nitritation-denitriation process was applied Results: The efficiency of the EGSB process showed that it has an 80% or more organic matter (CODcr) removal efficiency with an HRT of six hours or more at influent loadings of 17.34 kgCOD/$m^3$/day or less. The methane product for TCODcr removal was 0.23-0.38 $m^3CH_4$/kgCODrem., which was similar to the theoretical generation of STP-state methane, 0.35 $m^3CH_4$/kgTCODrem. In the nitritation-denitritation process, the nitritation conversion rate to $NH_4^+$-N concentration was 82% to 87%, 72% to 81% and 64% to 69% when HRT was 24 hr, 21 hr and 18 hr, respectively. In the denitritation process, the ratio of SCOD consumption to NOx-N removal ranged from 2.347 to 2.587. It was 2.472 on average. Conclusions: The optimal HRT for stable processing of seafood processing wastewater is six hours or more. The ratio of nitrite to total NOx-N was 82% to 96%, which indicates that nitrite accounts for the largest portion of the product.

• E2M - 전기 전자와 첨단 소재
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• 제10권8호
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• pp.830-835
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• 1997

In this study an experimental investigation has been conducted to remove NOx and SO$_2$simultaneously from a combustion flue gases were consisted of NO-SO$_2$-$CO_2$-$N_2$-O$_2$([NO]o:200ppm and [SO$_2$]o:800ppm) and the injection gases used as radical source gases were NH$_3$-Ar-air and CH$_4$-Ar-air. NOx and SO$_2$removal efficiency and the other by-products were measured by Fourier Transform Infrared(FTIR) as well as SO$_2$, NOx and NO$_2$gas detectors. and SEM images after sampling. The results showed that a significant Nucleating Particle Counter(CNPC) and SEM images after sampling. The results showed that a significant aerosol particle formation was observed during a simultaneous NOx and SO$_2$removal operation in corona radical shower systems. The diameter of aerosol particles was in the range of 0.18 to 3.6${\mu}{\textrm}{m}$ with a maximum fraction of particles at particles diameter of 1${\mu}{\textrm}{m}$. The NOx removal efficiency significantly increased with increasing applied voltage and NH$_3$molecule ratio. The SO$_2$removal efficiency was not significantly effected by applied voltage and slightly increased with increasing NH$_3$molecule ratio. It could be found that it is possible to use CH$_4$for NOx and SO$_2$removal by corona radical shower systems.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2000년도 제20회 KOSCO SYMPOSIUM 논문집
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• pp.152-161
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• 2000

The catalytically stabilized combustion of $CH_4$-air mixture on platinum catalyst was investigated numerically using a 2-D boundary layer model with detailed heterogeneous and homogeneous chemistries. The actual surface site density of monolith coated with platinum was decided by the comparison with experimental data. The comparisons were made between results for cases where only heterogeneous chemistry was allowed and both heterogeneous and homogeneous chemistries were allowed. It was found that the homogeneous reaction in the monolith had little effect on the change of temperature profile, methane conversion rate and light off location. The contributions of each reactions related with CO formation were discussed on the surface. The effects of operation conditions such as equivalence ratio, temperature, velocity and pressure at the entrance were studied. In thermal combustor, CO and NOx was produced less than 1 ppm at the exit and the production of $N_{2}O$ was more dominant than that of NO.

• 융합정보논문지
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• 제11권7호
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• pp.111-117
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• 2021

본 연구는 LFG(Land Fill Gas)의 주성분인 메탄(CH₄) 60%와 이산화탄소(CO₂) 40%로 구성된 매립지가스를 활용하여 정적연소 환경에서 연소의 초기 불안정성을 해결할 수 있는 실험적인 연구결과를 제안하는 것이다. 실험조건은 공기과잉율 0.9~1.6, 초기연소를 위한 압축압력 3bar, 실험주변온도 25℃, 실험용 연료가스 메탄, 예연소실 화염 분출구 직경 2.5, 3.0, 3.5, 4.0, 4.5mm로 설정하였다. 실험결과 M3.0 모델에서 초기화염의 확산성이 매우 증가된 특성을 확인할 수 있으며, 이와 같은 증가의 특성은 공기 과잉률이 0.9, 1.0, 1.2에서 오리피스의 효과가 극도로 향상하게 되었다는 점을 알 수 있었다. 결과적으로, 본 실험을 통하여 M3.0으로 설계된 예연소실 화염 분출구 치수를 LFG에 적용할 경우 기존의 점화 플러그 특성 보다 부분적인 연소의 성능을 높일 수 있다는 점을 확인할 수 있었다.

• 유기물자원화
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• 제24권1호
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• pp.21-29
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• 2016

혐기성 소화의 주요 조건 중 하나인 C/N비의 경우 하수슬러지는 5.40으로 낮게 나타난 반면 음폐수(Food waste leachate)는 21.84로 높게 나타났다. C/N비가 낮을 경우 혐기성소화의 저해 요인으로 작용될 수 있기 때문에 음폐수의 높은 유기물 농도 및 C/N 비를 활용하여 메탄가스 발생량 증가시킬 수 있었다. Tchobanoglous이 제안한 이론적 메탄가스 발생량 예측수식을 적용하여 메탄 및 바이오가스 발생량을 산정한 결과 하수슬러지 단일 혐기소화의 경우 $305.6mL{\cdot}CH_4/g{\cdot}VS$, $689.4mL{\cdot}CH_4/g{\cdot}VS$의 메탄, 바이오가스가 발생하였고 음폐수 : 하수슬러지를 1:9로 혼합한 시료는 약 $322mL{\cdot}CH_4/g{\cdot}VS$, 3:7시료에서는 약 $354mL{\cdot}CH_4/g{\cdot}VS$, 5:5시료에서는 약 $386mL{\cdot}CH_4/g{\cdot}VS$의 메탄가스가 발생하는 것으로 분석되었다. BMP 실험 결과 1:9, 3:7, 5:5 비율로 병합 처리한 경우 각각 약 233, 298, $344mL{\cdot}CH_4/g{\cdot}VS$의 메탄가스가 발생하였다. 따라서 음폐수의 혼합비율이 높아질수록 메탄가스 발생량은 증가하였고 하수슬러지와 음폐수의 혼합비율에 따른 병합처리 시 하수슬러지 단독처리에 비해 다량의 메탄가스가 발생되었다. BMP 실험을 통해 생산된 메탄가스의 누적생산 곡선을 Modified Gompertz model과 first order kinetic model에 적용하여 추정한 결과, 메탄생성량은 Modified Gompertz model에서는 238.5, 302.3, $353.6mL/g{\cdot}VS$ 발생하였고 first order kinetic model에서는 242.8, 312.5, $365.5mL/g{\cdot}VS$로 음폐수와의 혼합비율이 증가할수록 높게 나타났으며, 최대 메탄생성속도의 경우 3:7비율에서 $48.2mL/gVS{\cdot}day$로 최대 메탄생성 속도를 보였다. first order kinetic model의 1차 반응속도상수 k값은 1:9, 3:7, 5:5 비율에 따라 0.32, 0.22, $0.08day^{-1}$ 나타났다. 1차 반응속도 상수의 경우 음폐수의 혼합비율이 낮을수록 높게 나타났다. Modified Gompertz와 first order kinetic model 모두 실험결과를 잘 모사하였으며, 실험결과와 모의결과의 적합도를 나타내는 상관계수($R^2$)의 경우 0.92~0.98으로 높은 상관성을 나타내었다.

• 열처리공학회지
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• 제33권1호
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• pp.20-24
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• 2020

Single crystal diamonds are in great demand in such fields as mechanical, electronic applications and optoelectronics. Large area single crystal diamonds are attracting attention in future industries for mass production and low cost. In this study, hot filament CVD (HFCVD) is used to grow large area single crystal diamond. However, the growth rate of large area single crystal diamond using HFCVD is known to be very low. The goal of this study is to use single crystal diamond substrates in HFCVD with methane-hydrogen gas mixtures to increase the growth rate of single crystal diamond and to optimize the conditions by analysing the effects of deposition conditions for high quality crystallinity. The deposition pressure, the ratio of CH₄/H₂ gas, the substrate temperature and the distance between the filament and the substrate were optimized. The sample used a 4×4 (mm²) size single crystal diamond substrate (100), the CH₄/H₂ gas ratio was fixed at 5%, the substrate temperature was synthesized to about 1000℃. At this time, the deposition pressure was changed to three types of 50, 75, 85 Torr and deposited. Finally, optimization was investigated under pressure conditions to analyse the growth rate and quality of single crystal diamond.

• 공업화학
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• 제35권2호
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• pp.134-139
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• 2024

메탄의 수증기 개질 반응에서 Ni 기반 촉매에 귀금속 Ru 및 Pd을 조촉매로 첨가하여 촉매의 활성 및 수소 생산에 미치는 영향을 분석하였다. 합성된 촉매는 허니컴 구조의 금속 모노리스 구조체 표면에 코팅하여 수증기 메탄 개질 반응을 수행하였다. 촉매의 특성은 XRD, TPR 및 SEM으로 분석하였으며 개질 반응 후 가스를 포집하여 GC로 조성을 분석한 후 메탄의 전환율, 수소 수율 및 CO 선택도를 측정하였다. 0.5 wt%의 Ru 첨가는 Ni의 환원 특성을 개선하였고, 99.91%의 메탄 전환율로 향상된 촉매 활성을 나타내었다. 또한, 다양한 공정 조건에 따른 반응 특성을 분석하였으며, 800 ℃의 반응 온도, 10000 h^-1 이하의 공간속도(GHSV), 3 이상의 H₂O와 CH₄의 비(S/C)에서 90% 이상의 메탄 전환율과 3.3 이상의 수소 수율을 얻을 수 있었다.

• 한국수소및신에너지학회논문집
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• 제22권6호
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• pp.772-779
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• 2011

New type of syngas generator based on the partial oxidation of biogas in volumetric permeable matrix reformers was suggested as an effective, adaptable and relatively simple way of syngas and hydrogen production for various low-scale applications. The use of biogas as an energy source reduces the chance of possible emission of two greenhouse gases, $CH_4$ and $CO_2$, into the atmosphere at the same time. Its nature of being a reproducible energy source makes its use even more attractive. Parametric screening studies were achieved as air ratio, biogas component ratio, input gas temperature, Steam/Carbon ratio. As the air ratio was low, the production of the hydrogen and carbon monoxide increased in the condition that 3D matrix reformer maintains the stable driving. As it was the simulation biogas in which the carbon dioxide content is high, the flammable range became narrow. And the flammable range was extended if the injected gas was preheated. The stable driving was possible in the low air ratio. The amount of hydrogen production was increased as S/C ratio increased.

• 환경위생공학
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• 제16권2호
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• pp.17-23
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• 2001

The objective of this study was to investigate the component ratio of gas generated at closed GD landfill site in MY city and the decomposition status of landfill gas, and was to examine and analyze the properties of the landfill gas. In addition, to provide basic data required to stabilize landfill earlier in the future, the study was to measure gas by landfill gas gauge and to analyze the properties of landfill gas based on documents. As a result of analyzing the properties, acquired follow results. 1. The main elements of landfill gas, $CH_4$ and $CO_2$ were respectively 25.02% and 22.325 on the average. 2. $NH_3$ and $H_2S$ were respectively 1.07 4.97 and 0.75 1.15 on the average. 3. Generated gas was different depending on water, pH properties of MSW(Munticipal Solid Wastes) and their decomposition rate. Furthermore, when measured the temperature of room to inspect landfill gas, the temperature was $22{\;}-{\;}30^{\circ}C$ in the average.