• 한국화재소방학회논문지
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• 제16권3호
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• pp.77-83
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• 2002

질소, 아르곤, 이산화탄소와 같은 불활성가스 및 이들의 혼합물을 소화약제로 하여 n-Heptane을 연료로한 cup-burner test 장치에서 불꽃소화농도와 연소시 배가스의 조성을 측정하였다. 이성분 불활성가스계 혼합소화약제의 소화농도는 혼합물의 구성비를 이용한 모델에 의해 잘 예측됨을 알 수 있었다. 불활성 가스계 혼합 소화약제에 의한 소화작용에 있어서 혼합가스의 평균비중이 클수록 소화 성능이 우수하였다. 또한 밀폐된 공간의 구조가 소화에 영향을 미칠 수 있음을 확인하였다. 연소시 배가스 중 이산화탄소 조성은 사용하는 소화약제의 양이 증가할수록 감소하였다. 일산화질소 발생은 소화약제의 질소 함량과는 상관이 없으며 공기유량을 크게 하여 불꽃을 크게 했을 때 검출되었다.

• Advances in environmental research
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• 제6권3호
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• pp.189-202
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• 2017

This study examines the concentrations of particulate-phase polycyclic aromatic hydrocarbons (PAHs) and gas-phase PAHs in sidestream cigarette smoke. Sixteen PAHs were determined for four brands of cigarettes. The volume of the experimental room is approximately $66m^3$. The air samples in the room were collected before and after smoking. The median total of particulate-phase and gas-phase PAH concentrations before smoking $3.13ng/m^3$and $48.0ng/m^3$, respectively. The median concentrations of them after smoking were $10.0ng/m^3$ and $79.6ng/m^3$. The median increases in the total of 16 PAH concentrations per cigarette during smoking were 271 ng for the particulate-phase PAHs and 1960 ng for the gas-phase PAHs. According to the relationship between particulate-phase and gas-phase PAHs after smoking, the two- to four-ring gas-phase PAHs and the higher molecular weight particulate-phase PAHs were probably formed from similar precursors. The relationship between the total suspended particulate (TSP) concentration and the increase in the total particulate-phase concentration of the 16 PAHs per cigarette during smoking were significantly positive. The increase in the total gas-phase concentration of the 16 PAHs tended to increase as the TSP concentration increased. This may indicates that decreasing the amount of TSP produced inhibit the production of PAHs during smoking.

• 한국수소및신에너지학회논문집
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• 제20권6호
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• pp.479-484
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• 2009

The effect of anode gas channel height on gas diffusion and cell performance in a 100 $cm^2$ class molten carbonate single cell is investigated. Single cell separators with three different channel height are used. The effect of the gas channel height on the distribution of the reactive gas concentration is evaluated by the two-dimensional concentration diffusion equation. The overpotential caused by concentration drop with different channel height is estimated by the voltage decay related to diffusion of reactants, well known as concentration polarization, using limiting current density. The estimation could have the possibility to identify the reactant mass transfer polarization in the complicate factors of the overall electrodes.

• 상하수도학회지
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• 제26권5호
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• pp.649-658
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• 2012

In this study, the influencing factors for efficient anaerobic digestion of high strength ammonia-nitrogen wastewater removal were investigated by testing biochemical methane potential test. In the influencing factors, the trace metals which could increase activity of anaerobic microorganisms, microbial concentration and types were evaluated. In the results, trace metals supplementation showed gas production amount higher than those without addition of trace metals. Among the tested trace metals, B, Ni, and Se were preferable to gas production. In the result of gas production according to the microbial concentration, the amount of gas production was proportional to the microbial concentration. In addition, the shortest lag time and the fastest gas production rate were achieved when the highest microbial concentration was tested. granule-type microorganism produced more gas than suspended-type microorganism. In conclusion, the efficient anaerobic digestion for high strength ammonia-nitrogen wastewater removal could be achieved by applying necessary trace metals injection and high concentration granule type microorganism.

• 한국수소및신에너지학회논문집
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• 제30권6호
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• pp.601-607
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• 2019

Ammonia would be formed in natural gas containing small amount of nitrogen reforming process in the process natural gas, which might damage the Pt catalyst and Prox catalyst. In the article, the effect of nitrogen contents on the formation of ammonia in the reforming process has been studied. In the experiments, Ru based and Ni based catalysts were used and the concentration of ammonia in the reformate gas at various gas hourly space velocity was measured. Experimental result shows that relatively higher ammonia concentration was measured with Ru based catalyst than with Ni based catalyst. It also shows that the concentration of ammonia increased rapidly after most of the methane converted into hydrogen. Based on the experimental results to reduce ammonia concentration it might be better to finish methane conversion at the exit position of the reforming reactor to minimize the contact time of catalyst and nitrogen with high concentration of hydrogen.

• 한국분무공학회지
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• 제18권2호
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• pp.81-86
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• 2013

To comply with the regulation of the reinforcing Clean Air Conservation Act, it is necessary for the semiconductor manufacturers to develop effective low-concentration acid gas abatement system to treat the flue gas. The low-concentration acid gas was found to be harder to deal with than the high-concentration one. In this study, the effect of various potential treatments such as air-assist nozzle spraying, magnetizing the scrubbing water, and adding surfactants to spraying and scrubbing water were investigate through the application of the statistical ANCOVA method, which was proved to be very useful tool when the inlet concentration of acid gas could not be controlled precisely and it affected the removal efficiency of the abatement system.

• 대한조선학회 특별논문집
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• 대한조선학회 2006년도 특별논문집
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• pp.59-64
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• 2006

Most important factor to consider funnel performance is exhaust gas temperature and exhaust gas concentration Electric equipments on the wheelhouse top affected exhaust gas temperature. So, it is important that electric equipments keep away from high temperature. Though exhaust gas concentration is not a regulation and restraint, the exhaust 9as can cause serious problems for the on-board air quality and result in irreversible damage to the ship and people. So, we pocus on the exhaust gas concentration also. When judge whether a measured concentration is acceptable or not, criteria based on the LTEL (Long Term Exposure Limit). In this paper, we carried out the smoke simulation study. For this analysis, we used FLUENT which is commercial CFD (Computational Fluid Dynamics) code.

• Journal of Advanced Marine Engineering and Technology
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• 제18권2호
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• pp.91-96
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• 1994

Intake gases other than air, which is composed of oxygen, nitrogen, carbon dioxide, and argon, are used to study their effects on the performance of the diesel engine experimentally. The engine is operated at constant speed and fixed fuel injection timing, and cylinder pressure and heat release rate are measured at various intake gas compositions. The results show that increase of oxygen concentration improves the performance of the engine generally. The adverse effect is observed when the oxygen concentration is increased over the critical oxygen concentration of this test, mainly because of the over-shortened ignition delay. Increase of carbon dioxide concentration degardes the performance of the engine, mainly due to the lower specific heat ratio of carbon dioxide. Adding argon gas to the intake gas improves the overall performance. Finally, it is found that two most influencing factors affecting the performance of the diesel engine in this study are ignition delay and speific heat ratio of the intake gas.

• 한국화재소방학회논문지
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• 제17권4호
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• pp.111-116
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• 2003

가로, 세로, 높이가 각각 100cm, 60cm, 45cm로 내용적이 $270\ell$인 폭발 용기를 이용하여 불균일 농도 상태의 LPG-공기 혼합가스의 폭발특성을 측정하였다. 폭발은 vented-explosion과 closed explosion의 조건에서 실시하였다. 실험의 변수로는 점화원의 위치, 노즐직경 및 유속으로, 시료가스를 주입하는 노즐의 직경과 유속을 변화시키면서 용기 내에서의 불균일 혼합정도를 조절하였다. 폭발압력은 strain형 압력센사를 사용하여 측정하였고 폭발화염의 거동은 비디오카메라로 측정하여 분석하였다. 실험결과 유속과 가스 주입 시간이 용기 내 가스 혼합에 중요한 요소임을 알 수 있었으며, 불균일 정도가 심화될 수록 폭발압력과 압력상승속도가 감소하였으나 용기 내 폭발화염의 체류시간은 크게 증가하였으며 이로 인하여 가스 폭발 후 화재로의 전이 위험성이 증가함을 알 수 있었다.

• 유기물자원화
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• 제18권1호
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• pp.66-72
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• 2010

본 연구는 경기도 A지역 자원회수시설에서 연소온도의 변화에 따른 NOx, SOx, CO, HCL, DUST의 발생변화와 보일러 배출가스 온도, 보일러 출구산소 농도, 반건식 반응탑 출구온도, 촉매탑온도, 배출가스 온도의 변화를 분석하였다. SOx, CO, Hcl, DUST는 자원회수시설 내의 연소온도가 상승함에 따라 거의 5 ppm 미만의 일정한 값을 유지한 반면 NOx 는 40 ppm에서 70 ppm으로 증가하는 추세였다. 한편 보일러 배출가스 온도와 촉매탑 온도는 일정치를 유지하였으나 보일러 출구의 산소농도는 조금씩 감소하는 결과를 나타내었다.