• Nuclear Engineering and Technology
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• 제44권1호
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• pp.21-32
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• 2012

Fluorinated compounds mainly used in the semiconductor industry are potent greenhouse gases. Recently, thermal plasma gas scrubbers have been gradually replacing conventional burn-wet type gas scrubbers which are based on the combustion of fossil fuels because high conversion efficiency and control of byproduct generation are achievable in chemically reactive high temperature thermal plasma. Chemical equilibrium composition at high temperature and numerical analysis on a complex thermal flow in the thermal plasma decomposition system are used to predict the process of thermal decomposition of fluorinated gas. In order to increase economic feasibility of the thermal plasma decomposition process, increase of thermal efficiency of the plasma torch and enhancement of gas mixing between the thermal plasma jet and waste gas are discussed. In addition, noble thermal plasma systems to be applied in the thermal plasma gas treatment are introduced in the present paper.

• Journal of Mechanical Science and Technology
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• 제18권12호
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• pp.2303-2309
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• 2004

Flue gas recirculation (FGR) is a method widely adopted to control NOx in combustion system. The recirculated flue gas decreases flame temperature and reaction rate, resulting in the decrease in thermal NO production. Recently, it has been demonstrated that the recirculated flue gas in fuel stream, that is, the fuel induced recirculation (FIR), could enhance a much improved reduction in NOx per unit mass of recirculated gas, as compared to the conventional FGR in air. In the present study, the effect of FGR/FIR methods on NOx reduction in turbulent swirl flames by using N$_2$ and CO$_2$ as diluent gases to simulate flue gases. Results show that CO$_2$ dilution is more effective in NO reduction because of large temperature drop due to the larger specific heat of CO$_2$ compared to N$_2$ and FIR is more effective to reduce NO emission than FGR when the same recirculation ratio of dilution gas is used.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2002년도 제25회 KOSCI SYMPOSIUM 논문집
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• pp.65-69
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• 2002

Catalytic combustion known as one of the traditional oxidation methods of VOC gas is restricted to its applicable fields because of its reaction characteristics. But recently innovative improvement of catalytic endurance makes its applicable range broader from MEMs to industrial power generation. Therefore, control technologies based on the catalytic combustion characteristics are researched and developed dynamically. Especially, the stable control of catalytic combustion is an essential factor in a view of maximizing its efficiency. In this research, the fuel equivalence ratio and the preheating temperature of mixture gas is controlled by catalytic combustion system enhanced in heat transfer with high temperature heat exchanger. As a result, the combustion characteristics of system was investigated, and both passive and active control type were compared and analyzed.

• 한국가스학회지
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• 제9권1호
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• pp.21-25
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• 2005

가스보일러용 오스테나이트계 스테인리스강재(STS 304)의 부식거동에 관해 연구하기 위하여, 응축수중에서 전기화학적 부식시험을 수행하여. STS 304의 전기화학적 부식거동을 고찰하였다. 다음과 같은 결론을 얻었다. 1)중성환경인 pH=6.5에서 pH가 낮아질수록 STS 304의 분극저항은 감소하고, 부식전위는 비전위화된다. 2)중성 및 산성환경 중에서 STS 304의 부식반응기구는 음극지배로 판단된다. 3) pH가 중성 환경인 pH=6.5에서 강산성 환경인 pH=0.5로 낮아질수록 STS 304의 부동태 전위영역이 감소하고 부동태유지 전류밀도는 증가하고 있다.

• 접착 및 계면
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• 제21권2호
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• pp.51-57
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• 2020

최근 산업활동을 통해 배출되는 유해 오염물질 제거에 대한 관심이 증가하고 있다. 본 연구에서는 수증기 활성화 법을 이용하여 활성탄소섬유를 제조하고, 이의 유해가스 흡착 및 전기화학적 감응 특성을 분석하였다. 활성탄소섬유의 균일한 기공 구조, 활성 반응 면적 및 반응 위치를 조절하기 위하여, 활성화 온도(750-850 ℃) 및 활성화 시간(30-240 min)을 조절하였고, 다양한 활성화 조건을 통해 제조된 활성탄소섬유의 SO₂와 NO 가스 흡착 및 가스 센서를 통한 감응 특성을 분석하였다. 특히, 850 ℃에서 45 min동안 수증기 활성화 반응을 통해 제조된 활성탄소섬유가 가장 높은 비표면적(1,041.9 ㎡/g)과 기공 특성(0.42 ㎤/g)을 보였으며, 우수한 SO₂ (1.061 mg/g) 및 NO (1.210 mg/g) 가스 흡착 특성을 보였다.

• 공업화학
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• 제7권3호
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• pp.573-579
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• 1996

공업적 기포탑 반응기의 설계, scale-up, 조절, 개발 및 운전에 매우 긴요한 기초자료들을 얻기 위하여 실험 실적 규모의 기포탑 반응기에서 각 실험변수들이 ortho 붕산으로부터 meta 붕산의 생성 반응전환율에 미치는 영향을 연구하였다. 반응시간 및 압력, 반응물의 입자크기 및 기체 유속 등을 실험변수로 선택하였으며, 이들 실험변수들이 기포탑 반응기내의 기체 체류량에 미치는 영향들을 반응의 전환율과 연계하여 또한 검토하였다. 연구의 결과, 다음과 같은 최적 반응조건을 얻을 수 있었다 : 반응시간 ; 35~40(분), 반응압력 ; 92~95(kPa), 반응입자의 크기 ; $0.6{\times}10^{-3}(m)$ 이하, 기체 유속 ; 0.07~0.08(m/s).

• 한국분무공학회지
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• 제20권3호
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• pp.149-155
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• 2015

With increasing of GDP, the registration number of passenger cars has exceeded 20 million last year in Korea. Especially, the registration number of the diesel engine vehicles has been increasing. However, the WHO(World Health Organization) IARC (International Agency for Research on Cancer) has reported that diesel engine exhaust gas is an one of HAPs, which has carcinogenic for human, and they have designated it to Group 1. To solve this problem, exhaust gas from diesel engines has to be controlled. Thus, it has been controlling by European regulatory standard in Korea. On the other hand, in order to meet the enhanced emission regulations, all manufacturing company applied $NO_x$ control device to vehicles such as EGR (Exhaust Gas Recirculation), SCR (Selective Catalytic Reduction) and so on. However, these devices (EGR, SCR) were operated by difference reaction mechanism respectively, and the composition of exhaust gas would be differenced from that of them. In this study, it was conducted to evaluate variety characteristics on changing of exhaust gas composition by each $NO_x$ control device, and the heavy duty diesel trucks were chosen as experimental vehicles. From the result, it revealed that vehicles (with EGR) were discharged higher THC as 52.5% than that of others (with SCR). However, it did not followed that trend, in the case of CO; it was discharged as 57.2% lower than that of others (with SCR). In the future, these data would be used to apply to efficient $NO_x$ control device for meeting to EURO 6.

• 한국전기전자재료학회논문지
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• 제23권12호
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• pp.915-918
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• 2010

In this work, the etching characteristics of ZnO thin films were investigated using an inductively coupled plasma(ICP) of HBr/Ar/$CHF_3$ gas mixtures. The plasma characteristics were analyzed by a quadrupole mass spectrometer (QMS) and double langmuir probe (DLP). The surface reaction of the ZnO thin films was investigated using X-ray photoelectron spectroscopy (XPS). The etch rate of ZnO was measured as a function of the $CHF_3$ mixing ratio in the range of 0-15% in an HBr:Ar=5:2 plasma at a fixed gas pressure (6mTorr), input power (700 W), bias power (200 W) and total gas flow rate(50sccm). The etch rate of the ZnO films decreased with increasing $CHF_3$ fraction due to the etch-blocking polymer layer formation.

• 폴리머
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• 제37권5호
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• pp.553-556
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• 2013

본 연구에서는 고분자 수화젤 비드 내부에 아세트산을 탑재시킨 후, 분무와 함께 수화젤로부터 방출된 아세트산이 아염소산나트륨과 반응하여, 저농도의 이산화염소 기체를 장시간 지속적으로 발생시킬 수 있는 장치를 개발하였다. 폴리아크릴아미드 수화젤 비드에 탑재시킨 아세트산의 함량과 부직포에 코팅한 아염소산나트륨의 함량을 변화시키면서 발생하는 이산화염소 기체의 생성량을 측정한 결과, 수화젤로부터 아세트산이 방출된 후 반응을 하기 때문에 직접반응에 의한 것보다 반응시간이 지연되어 저농도의 이산화염소 기체가 지속적으로 생성되도록 제어하는 것이 가능하였다. 이러한 결과는 본 연구가 목적으로 하는 저농도의 이산화염소를 장시간에 걸쳐서 지속적으로 생성할 수 있는 장치를 고분자 수화젤을 이용하여 구현할 수 있음을 보여준다.

• 한국세라믹학회지
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• 제29권9호
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• pp.681-688
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• 1992

Ultrafine Si3N4 and Si3N4+SiC mixed powders were synthesized through thermal plasma chemical vapor deposition(CVD) using a hybrid plasma, which was characterized by the supersposition of a radio-frequency plasma and arc jet. The reactant SiCl4 was injected into an arc jet and completely decomposed in a hybrid plasma, and the second reactant CH4 and/or NH3 mixed with H2 were injected into the tail flame through double stage ring slits. In the case of ultrafine Si3N4 powder synthesis, reaction efficiency increased significantly by double stage injection compared to single stage one, although crystallizing behaviors depended upon injection speed of reactive quenching gas (NH3+N2) and injection method. For the preparation of Si2N4+SiC mixed powders, N/C composition ratio could be controlled by regulating the injection speed of NH3 and/or CH4 reactant and H2 quenching gas mixtures as well as by adjusting the reaction space.