• 제목/요약/키워드: Nitrogen Oxides

검색결과 457건 처리시간 0.026초

수원시 대기 중 오존과 질소산화물의 장기변동 특성 (1991 ~ 2012) (The Long-term Variations of Ozone and Nitrogen Oxides in Suwon City during 1991 ~2012)

  • 안현진;한지현;이미혜;강은하
    • 한국대기환경학회지
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    • 제31권4호
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    • pp.378-384
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    • 2015
  • The long-term variations of ozone and nitrogen oxides in Suwon city, the capital of Gyeong-gi province, were examined from 1991 to 2012. In this period, the annual average $O_3$ concentration increased from 13.8 ppbv to 22.7 ppbv and that of $99^{th}$ percentile increased from 58.0 ppbv to 80.0 ppbv. The monthly average and $99^{th}$ percentile of $O_3$ concentrations were the highest in June. The increase in $O_3$ concentration was the greatest in early summer (May and June) before monsoon season began. While the concentrations of NO and NOx have gradually decreased since 2000, $NO_2$ remained unchanged. As a result, $NO_2/NO_x$ ratio increased from 0.5 to 0.73 in 2012. The monthly $NO_2/NO_x$ ratio was the highest in early summer, when monthly average $O_3$ concentration was the highest. It suggests that the enhanced $NO_2/NO_x$ ratio is intimately coupled with increase in $O_3$ for the last two decades in Suwon.

부분부하에서 비에스테르화 바이오디젤 5% 혼합유의 성능최적화를 위한 실험계획법 적용에 관한 연구 (A study on the application of DOE for optimization of blending oil with non-esterified biodiesel fuel at partial engine load)

  • 김희중;고대권;양주호;고성위;김영식;정태영;정석호
    • 동력기계공학회지
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    • 제20권2호
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    • pp.51-57
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    • 2016
  • Non-esterified biodiesel fuel is cheaper than esterified that because of a simple manufacturing process that only consists of filtering. Applicability of this on diesel engine with electronic control system was accomplished, then optimization adopting a fractional factorial design and response surface methodology was carried out at 25% and 50% of engine load in this study. Pressure of common rail and injection timing mainly effected on responses as specific fuel oil consumption and nitrogen oxides regardless of engine load. Estimations were 310.3 g/kWh of specific fuel oil consumption and 237 ppm of nitrogen oxides at 25% load, and 233.2 g/kWh of specific fuel oil consumption and 730 ppm of nitrogen oxides at 50% load. Tests to verify these estimations were accomplished and as the results, specific fuel oil consumption was 300.4 g/kWh and NOx was 277 ppm at 25% load and 236.8 g/kWh and 573 ppm at 50% load.

1,2-Dichlorobenzene 및 질소산화물 동시제거를 위한 촉매연구 (A Study on Catalysts for Simultaneous Removal of 1,2-Dichlorobenzene and NOx)

  • 박광희;홍성창
    • 공업화학
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    • 제20권5호
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    • pp.522-526
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    • 2009
  • 다양한 금속(Ru, Mn, Co, Fe)을 $Al_2O_3$$CeO_2$에 담지한 촉매를 이용하여 1,2-Dichlorobenzen (1,2-DCB) 제거를 위한 촉매산화 실험을 실시하였다. 이와 더불어 동시에 NOx 제거가 이루어져 단일 촉매층에서 산화/환원 이원 기능이 가능한 촉매를 연구하고자 하였다. 실험결과 1,2-DCB 산화제거효율은 Ru/Co/$Al_2O_3$, Mn-Fe/$CeO_{2}$, 상용촉매인 Cr/$Al_2O_3$ 순으로 나타났다. 또한 1,2-DCB 산화제거효율이 가장 우수하였던 Ru/Co/$Al_2O_3$는 Chlorobenzene (CB)의 분해실험에서도 VOC 제거에 있어서 잘 알려진 Pt-Pd/$Al_2O_3$ 보다 우수한 활성을 나타내었다. 또한 $Cl_2$와 같은 생성물에 의하여 활성의 저하 및 황에 대한 내피독성과 내구성에서 우수한 결과를 얻을 수 있었다. NOx 제거에 있어서도 $260^{\circ}C$에서 NOx 전환율이 70% 정도로 나타났다.

간헐적 플라즈마 방전이 질소산화물의 탄화수소 선택적 촉매환원에 미치는 영향 (Effect of Intermittent Plasma Discharge on the Hydrocarbon Selective Catalytic Reduction of Nitrogen Oxides)

  • 윤경환;목영선
    • 공업화학
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    • 제34권5호
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    • pp.507-514
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    • 2023
  • 촉매(Ag/γ-Al2O3) 충진형 유전체 장벽 방전 플라즈마 반응기를 이용한 질소산화물(NOx)의 선택적 촉매 환원을 조사하였다. 촉매 상에서 간헐적으로 플라즈마를 발생시킬 때 NOx의 환원제인 탄화수소가 부분 산화되어 알데하이드류를 생성하였으며, 알데하이드류의 높은 환원력으로 인해 촉매를 단독으로 사용한 경우에 비해 높은 NOx 전환율을 보여주었다. 동일한 운전 조건(온도: 250 ℃; C/N: 8)에서 비교한 NOx 저감 효율은 탄화수소(n-헵테인), 프로피온알데하이드, 뷰티르알데하이드에 대해 각각 47.5%, 92%, 96%로 나타났으며, 알데하이드류의 높은 질소산화물 환원 성능이 확인되었다. 간헐적 플라즈마 발생시 적정 조건을 파악하기 위하여, 고전압 on/off 주기를 0.5~3 min으로 조절하였고, 연속적인 플라즈마 발생의 경우와 동일한 에너지밀도에서 NOx 저감 성능을 비교하였다. 고전압을 2 min 간격으로 on/off 하여 간헐적으로 플라즈마를 생성시켰을 때 연속적인 플라즈마 발생 대비 가장 높은 질소산화물 저감 효율이 얻어졌다. 동일한 에너지밀도에서도 간헐적 플라즈마 방전의 경우가 연속 플라즈마에 비해 높은 NOx 저감 효율을 보이는 것은, 탄화수소가 분해되어 생성되는 알데하이드류 등의 중간생성물들이 NOx 저감 반응에 보다 효율적으로 이용되었기 때문이다.

표면처리된 탄소나노튜브의 질소 및 산소관능기 도입에 따른 전기화학적 특성 (Combined effect of nitrogen- and oxygen functional groups on electrochemical performance of surface treated multi-walled carbon nanotubes)

  • 김지일;박수진
    • 한국신재생에너지학회:학술대회논문집
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    • 한국신재생에너지학회 2011년도 춘계학술대회 초록집
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    • pp.214.1-214.1
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    • 2011
  • In this work, the electrochemical properties of the surface treated multi-walled carbon nanotubes (MWNTs) are investigated for supercapacitors. Nitrogen- and oxygen functional groups containing MWNTs are prepared by nitrogen precursors and acidic treatment, respectively. The surface properties of the MWNTs are confirmed by X-ray photoelectron spectroscopy (XPS) and Zeta-potential measurements. The electrochemical properties of the MWNTs are investigated by cyclic voltammetry, impedance spectra, and charge-discharge cycling performance in 1 M $H_2SO_4$ at room temperature. As a result, these functionalized MWNTs lead to an increase in the specific capacitance as compared with the pristine MWNTs. It proposes that the pyridinic and pyridinic-N-oxides nitrogen species influence on the specific capacitance due to their positive charges, and thus an improved electron transfer at high current loads, since they are the most important functional groups affecting capacitive behaviors.

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디젤엔진 배기가스중 질소산화물 저감을 위한 금속 산화물 촉매를 이용한 실험적 연구 (An Experimental Study on the Reduction of Nitric Oxides from the Diesel Engine Exhaust Gas with Metal Supported Oxides Catalysts)

  • 채재우;황재원;정지용;한정희;황화자;김석
    • 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.

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Reduction of Nitrogen Oxides from Fuel Nitrogen in New Fuelling System

  • 전영남;채재우
    • Bulletin of the Korean Chemical Society
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    • 제17권10호
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    • pp.885-892
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    • 1996
  • The effects of NOx reduction by advanced fuel staging in a small scale combustor (6.6 kWT) have been investigated using propane gas flames laden with ammonia as fuel-nitrogen. The variables which had the greatest influence on NOx reduction were temperature, reducing stoichiometry (relate to main combustion zone stoichiometry, air fraction and reburning fuel fraction) and residence time of reducing zone. NOx reduction was best at the reburning zone temperature of above 1,000 ℃ and reburning zone stoichiometry was 0.85. In terms of residence time of the reburning zone, NOx reduction was effective when burnout air was injected at the point where the reburning zone had been already established. In the advanced fuel staging NOx reduction was relatively large at the burning of higher Fuel-N concentration in the fuel. Under optimum reburning conditions, fuel nitrogen content had a relatively minor impact on reburning efficiency.

피트(peat) 혼합담체를 이용한 저농도 질소산화물(NOx) 제거특성 (Removal Characteristics of Nitrogen Oxides (NOx) in Low Concentration using Peat-Mixed Media)

  • 강영현;김덕우;강선홍;권필주;김달우;황필기;심상보
    • 한국대기환경학회지
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    • 제26권3호
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    • pp.330-338
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    • 2010
  • In this study, removal characteristics of nitrogen oxides $(NO_x)$ from road transport by using peat as the packing media for biodegradation have been investigated in the long term. Physicochemical and biological treatment of peatmixed media eliminates any requirement to use chemical substances and also facilitates the biodegradable actions of microorganism. Safe biodegradation of pollutants, no need to apply additional microbes owing to their active growth, and no generation of secondary pollutants were found in this experiment. It was concluded that average removal efficiencies of nitric oxide (NO) and nitrogen dioxide $(NO_2)$ were 80% and 97% respectively with respect to the linear velocity 35~40 mm/s and 0.3 ppm ozone concentration in the long period operation. Inflow concentration of nitric oxide over 0.05 ppm was suitable when pretreated with ozone. Non-ozone stage was performed with linear velocity 20~100 mm/s and then the average removal efficiency of nitric oxide and nitrogen dioxide were 38% and 94% respectively. Other results showed that the apparent static pressure was raised with increases in applied water content and aerial velocity in mixed media during fan operation.

INPUFF MODEL을 이용한 복잡지형의 질소산화물 확산 모델링 (Application of Diffusion Modeling to Nitrogen Oxides using INPUFF Model in Complex Terrain)

  • 박영한;이종범
    • 한국대기환경학회:학술대회논문집
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    • 한국대기환경학회 1999년도 추계학술대회 논문집
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    • pp.154-155
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    • 1999
  • 동해 지역은 험준한 태백산맥을 경계로 동해안 연안에 위치하고 있으며 공업항만의 발달로 지방 산업의 발전이 가속화되고 있다. 특히 다량의 연료를 사용하는 대기배출시설인 시멘트공장 3개소와 화력발전소 1개소가 밀집되어 대기질 악화가 우려되고 있으며, 주요 배출물질로는 먼지, 질소산화물, 일산화탄소 등이 있다.(중략)

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