• 한국구조물진단유지관리공학회 논문집
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• 제26권6호
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• pp.120-127
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• 2022

질소산화물(NOx)은 대기오염의 주요 인자로 일산화질소와 이산화질소의 형태로 존재하며 인체에 유해하다. 최근 대기 중 NOx를 제거하기 위한 많은 연구가 진행되고 있으며, 이러한 노력은 건설재료 분야에서도 동일하다. NOx는 광촉매 반응을 이용하여 효율적으로 제거할 수 있는 것으로 알려져 있다. 본 연구에서는 활성탄(AC)과 이산화타이타늄(TiO₂)을 이용한 폼 복합재의 NOx 제거성능을 조사하였다. AC는 폼 복합체의 비표면적을 증가시켜 TiO₂의 광촉매 반응 효율을 향상시켰다. 본 연구에서는 AC의 혼합율을 주요 변수로 하여 폼 복합체를 제조하였다. 제조된 시험체를 이용하여 ISO-22197-1에 제시된 시험방법에 따라 NOx 제거성능을 평가하였다. 폼 복합체의 비표면적은 AC 함량에 따라 증가하는 경향을 나타내었으나 15% 이상에서는 감소하였다. 또한 AC 혼입률이 15%일 때 NOx 제거 효율이 가장 높았다.

• 한국산학기술학회논문지
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• 제19권8호
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• pp.8-13
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• 2018

질소산화물은 최근에 초미세먼지 발생에 많은 영향을 주고 있어서 대기환경 개선 측면에서 사회적으로도 크게 관심이 되고 있다. 질소산화물은 주로 화력발전 등의 연소기기에서 고온의 연소가스 분위기에서 공기 중의 질소와 산소가 반응하여 발생한다. 이에 대한 저감 방법으로 원통형 버너에 코안다 노즐을 이용한 배관으로 배기가스를 재순환하는 연소에 대한 연구가 최근에 이루어지고 있다. 본 연구에서는 코안다 노즐을 사용하여 배기가스를 재순환하는 원통형 버너의 연소가스 출구의 위치를 오른쪽으로 하는 버너(Case 1 버너), 양쪽을 출구로 하는 버너(Case 2 버너), 왼쪽을 출구로 하는 버너(Case 3 버너) 형상에 대하여 전산유체해석을 통해 연구를 수행하였으며 연소 유동의 압력, 유선, 온도, 연소 반응 속도와 질소산화물의 분포 특성을 비교 분석하였다. 연소반응은 Case 1과 Case 2버너는 연소가스 재순환 유입구가 있는 오른쪽 방향으로 일어나고 Case 3 버너는 혼합가스 유입구 부근에서 일어나고 있었다. 출구에서의 온도는 Case 2버너가 양쪽으로 배출되면서 다른 버너 보다 약 $100^{\circ}C$ 정도 온도가 낮게 나타났으며 출구에서의 NOx 농도는 Case 1버너가 다른 형상 버너 보다 약 20배 크게 나타났다. 이로부터 NOx 저감을 위해서는 배기가스 재순환 버너의 출구는 양쪽으로 배출되게 하거나 연소가스 재순환 유입구 반대 방향으로 배출 되도록 하는 것이 효과적임을 알 수 있었다.

• Journal of Advanced Marine Engineering and Technology
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• 제35권3호
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• pp.317-322
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• 2011

This work has investigated the exhaust emissions such as Total Hydrocarbon (THC), Nitrogen Oxides(NOx), and Particulate Matter (PM) characteristics emitted from the tail-pipe of a continuously variable valve timing (CVVT) gasoline-fueled engine with different intake valve opening timings and injection pressures at the part load condition. Valve overlap period was varied from $40^{\circ}CA$ to $10^{\circ}CA$ and fuel injection pressure was increased from 3.5 bar to 5.0 bar. THC and NOx emissions decreased as intake valve opening timing was advanced regardless of fuel injection pressure. When the fuel was injected with the condition of 5.0 bar at all of valve overlap ranges, THC levels were reduced by 55%. NOx concentrations were diminished about 75% as valve overlap increased. PM size distributions were analyzed as bi-modal type of the nucleation and accumulation mode. Comparing with fuel injection pressures, PM emission levels were decreased at high pressure injection of 5.0 bar condition.

• 한국연초학회지
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• 제26권1호
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• pp.64-72
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• 2004

On-going research has recently documented the certain tobacco specific nitrosamines (TSNAs) are formed during the curing process by an interaction of nitrogen oxides (NOx) contained in combustion gases and naturally occurring compounds in the tobacco leaves. Although the role of TSNAs in human health have been extensively investigated, little research has been conducted on the physical and chemical phenomena relating to their formation during curing. In this paper, we developed a mathematical model for describing NOx absorption into green (uncured) tobacco. We found considerable uptake of NOx by green tobacco with variations related to several factors. Specifically, tobacco from the lower stalk positions (bottom one third) absorbs more NOx gas per unit weight than tobacco from upper stalk positions. Additionally, the green tobacco packed with a density of 0.103 g/㎤ absorbs more NOx gas per unit weight than either 0.0443 g/㎤ or 0.0739 g/㎤. Further, the NOx absorption increases proportionally with temperature with the maximum absorption point around 4$0^{\circ}C$.

• 한국전기전자재료학회논문지
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• 제20권9호
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• pp.821-827
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• 2007

The nitrogen oxides, NO and $NO_2$, abbreviated usually as NOx, emitted from combustion facilities such as power plants and automobiles are the typical air-pollutants causing acid rain and photochemical smog. In order to solve the NOx-related pollution problems effectively, we need efficient techniques to monitor NOx in the combustion exhausts and in environments. Development of solid-state electrochemical devices for detecting NOx is demonstrated based on various combination of solid electrolytes and auxiliary sensing materials. The object of this research is to develop various sensor performance for solid state amperometric sensor, and to test gas sensor performance manufactured. So we try to present a guidance for developing amperometric gas sensor. We concentrated on development of manufacturing process and performance test. Amperometric Nitrogen dioxide sensor was fabricated using NASICON and an $NaNO_2$ layer deposited on the counter electrode. The current response was almost linear with Nitrogen dioxide concentration in the range 1-350 ppb at $150^{\circ}C$.

• 한국안전학회지
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• 제16권3호
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• pp.41-44
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• 2001

The removal characteristics of nitrogen oxides (NOx) by the dielectric ($Al_2O_3$) packed-bed plasma reactor are experimentally investigated Reactor is packed with 5[mm] diameter $Al_2O_3$ beads, and was desisted to remove NOx at atmospheric pressures from the moving pollution source such as diesel automobile. The experiments were conducted for applied voltages from 5 to 10[kV], flue gas rate from 2 to 5[l/min] and frequency from 0.5 to 2[kHz]. The NOx removal efficiency significantly increasing with increasing applied voltage. Especially removal rate significantly increased with increasing frequency. However, in this experiment discharged poler n relatively high.

• Journal of Advanced Marine Engineering and Technology
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• 제32권7호
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• pp.1080-1088
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• 2008

This paper addresses some concerns faced by the shipping industry nowadays. Initially, the environmental issues were resolved and stricter regulations are now being implemented with regards to the exhaust gas, specifically nitrogen oxides (NOx) and sulfur oxides (SOx), emitted from ships. Secondly, with the increasing and unstable cost of fuel oils in the world market, it has become almost a necessity to explore on a new alternative fuel. Hence, this study was conducted. An experiment was carried-out on a fishing survey vessel with the main engine (M/E) and generator engine (G/E) operated on expensive marine gas oil (MGO). During the experiment, two pre-refinery systems were installed and different fuel oil samples were employed for the M/E and the G/E. Furthermore, the NOx emission and soot concentration were monitored and verified. The results confirmed the compatibility of some fuel oil types to the engines and meeting the emission standards. MDO, MF15 and Bunker A can be used in place of MGO for the engines(M/E, G/E).

• 한국자동차공학회논문집
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• 제9권3호
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• pp.68-75
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• 2001

In this paper, a number of supported metal oxides and perovskite type catalysts were investigated for the NOx reduction from the diesel engine exhaust gas. All catalysts were made into pellets type with diameter of 3-4 mm alumina(Al$_2$O$_3$) as a supporter. These samples were tested by real diesel exhaust gas which contains CO, hydrocarbons and soot in the temperature range of 150~55$0^{\circ}C$ with the $3300h^{-1}$ space velocity (SV). Among the results, several promising catalysts showed NOx conversion above 50% in the temperature range of 150-35$0^{\circ}C$. From these results supported metal oxides catalysts and perovskite type could be recommended for the practical application to the automobile exhaust treatments.

• 환경위생공학
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• 제15권4호
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• pp.78-83
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• 2000

The emission factor of nitrogen oxides(NOx) was evaluate to clarify the characteristics of NOx emitted from seven large combustion facilities in seoul area. The emission factors of NOx at A-1 and A-2 facilities of internal combustion engine were 66.957kgNOx/ton and 20.913kgNOx/ton, respectively. The emission factor of A-1 facility was higher than that of A-2 facility even same internal combustion engine, because A-1 facility adopted SCR(selective catalystic reactor) for reduction of NOx emission factor of A-2, A-4, and A-7 power generation boiler facilities were 4.300kgNOx/ton, 2.460kgNOx/ton and 1.796kgNOx/ton, respectively. The capacity of A-2 facility was about two times than that of A-4 and A-7. These emission factors were lower than those at facilities in other areas of korea, because of using low NOx burner of power generation boiler. The emission factors of NOx at A-3 and A-6 incinerator facilities were 0.147kgNOx/ton and 0.221kgNOx/ton which were lower than other facilities, respectively, because these facilities incinerate municipal solid waste of low heating value and uwe SCR for reducing NOx concentration.

• 한국분무공학회지
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• 제21권2호
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• pp.71-77
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• 2016

Air pollutants nitrogen oxides are inevitably generated in the combustion reaction. Its amount trend is steadily increasing because the rapid modern industrialization and population growth. For this reason, NOx is controlled to reducing the harmful components in the exhaust gas. So Marine Environment Protection Committee (MEPC) take effect 'Tier I', 'Tier II' of air pollution regulation in 2005 and 2011 respectively. According to NOx emissions are strictly regulated management of the vessel through them. In addition, since 2016 the regulation enter into force in the next step 'Tier III' was confirmed by MEPC 66th committee. It's 80% enhanced emissions limits than the 'Tier I' Alternatively these emission regulation, research is actively being carried out about exhaust gas after-treatment methods through the vessel application of Selective Catalytic Reduction(SCR). Therefore depending on the basic specification of cell density according to the Area velocity, Space velocity, Linear velocity is studied the effects of NOx removal efficiency