• Proceedings of the Korea Air Pollution Research Association Conference
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• 1997.10a
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• pp.192-193
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• 1997

• Applied Chemistry for Engineering
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• v.34 no.5
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• pp.507-514
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• 2023

The selective catalytic reduction (SCR) of nitrogen oxides (NO_x) was investigated in a catalyst (Ag/γ-Al₂O₃) packed dielectric barrier discharge plasma reactor. The intermittent generation of plasma in the catalyst bed partially oxidized the hydrocarbon reductant for NO_x removal to several aldehydes. Compared to using the catalyst alone, higher NO_x conversion was observed with the intermittent generation of plasma due to the formation of highly reductive aldehydes. Under the same operating conditions (temperature: 250 ℃; C/N: 8), the NO_x reduction efficiencies were 47.5%, 92%, and 96% for n-heptane, propionaldehyde, and butyraldehyde, respectively, demonstrating the high NO_x reduction capability of aldehydes. To determine the optimal condition for intermittent plasma generation, the high voltage on/off cycle was adjusted from 0.5 to 3 min. The NO_x reduction performance was compared between continuous and intermittent plasma generation on the same energy density basis. The highest NO_x reduction efficiency was achieved at 2-min high voltage on/off intervals. The reason that the intermittent plasma discharge exhibited higher NO_x reduction efficiency even at the same energy density, compared to the continuous plasma generation case, is that the intermediate products, such as aldehydes generated from hydrocarbon, were more efficiently utilized for the reduction of nitrogen oxides.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 1999.11a
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• pp.53-56
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• 1999

석탄 연소로 내에서는 어떠한 방식으로든 NH- 라디칼이 존재하게 된다. 즉, 배가스 처리 공정에서는 SNCR 방식에 의해 질소산화물 (NO) 저감할 경우 환원제로써 사용되는 암모니아 또는 요소와 같은 물질은 고온의 연소로에서 NH- 라디칼을 생성하게 되기도 하며, 순환유동층 연소로처럼 석탄을 원료로 사용하는 연소로에서는 석탄내에 포함되어 있는 N, H와 같은 원소들이 휘발하여 NH- 라디칼이 생성되기도 한다.(중략)

• Korean Chemical Engineering Research
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• v.49 no.1
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• pp.89-94
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• 2011

DeNOx characteristics of hybrid SNCR-SCR process have been investigated in a pilot scale flow reactor. DeNOx efficiency of SNCR reaction was about 80% at $970^{\circ}C$ and hybrid SNCR-SCR process showed 92% at $940^{\circ}C$ with NSR = 2.0. Compared to SNCR process alone, hybrid SNCR-SCR process was more effective at cool side, which is lower than $940{^{\circ}C}$. It should be also noted that ammonia slip from hybrid SNCR-SCR process was below 1ppm at the condition of higher space velocity and the required catalyst volume can be decreased to 2/3 of SCR process. Key factors for DeNOx efficiency of hybrid SNCR-SCR process were found to be $NH_3$ concentration and NOx selectivity of urea injected in SNCR process.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.2
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• pp.75-83
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• 2014

The present study estimated nitrogen budget of South Korea including nitrogen oxides (NOx) in 2011. Emission sources of NOx were calculated with the higher contributors, such as vehicles, businesses, power plants, based on the IPCC and EPA reports. Moreover, nitrogen budget was separated for city, agriculture livestock and forest. Input and output were chemical fertilizer, crop uptake, fixation, irrigation, compost, leaching, volatilization, imported food, denitrification, runoff, and so on. Annual nitrogen input were 1,692,650 ton/yr and output were 837,739 ton/yr which were increased from 2010 budget. In 2011, NOx emissions by vehicles, power plants, and businesses were 308,207 ton/yr, 601,437 ton/yr, and 469,946 ton/yr, respectively. Including nitrogen oxide, total nitrogen input and output in 2011 was calculated as 5,652,366 ton/yr and 1,425,371 ton/yr, respectively.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.37 no.5
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• pp.481-488
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• 2013

Nitric oxide ($NO_x$) formation characteristics in non-premixed diffusion flames of methane fuels have been investigated experimentally and numerically by adding 10% ammonia to the fuel stream, according to the variation of the oxygen ratio in the oxidizer with oxygen/carbon dioxide and oxygen/nitrogen mixtures. In an experiment of coflow jet flames, in the case of an oxidizer with oxygen/carbon dioxide, the $NO_x$ emission increased slightly as the oxygen ratio increased. On the other hand, in case of an oxygen/nitrogen oxidizer, the $NO_x$ emission was the maximum at an oxygen ratio of 0.7, and it exhibited non-monotonic behavior according to the oxygen ratio. Consequently, the $NO_x$ emission in the condition of oxyfuel combustion was overestimated as compared to that in the condition of conventional air combustion. To elucidate the characteristics of $NO_x$ formation for various oxidizer compositions, 1D and 2D numerical simulations have been conducted by adopting one kinetic mechanism. The result of 2D simulation for an oxidizer with oxygen/nitrogen well predicted the trend of experimentally measured $NO_x$ emissions.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2003.05b
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• pp.333-334
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• 2003

자동차로 인한 대기오염은 규제물질 뿐만 아니라 많은 미량유해물질들에 크게 기여하고 있다. 이러한 자동차 배출가스들은 1차 대기오염물질로 배출되기도 하지만 그중 탄화수소나 질소산화물 등은 대기중 광산화반응을 거쳐 2차 오염물질 생성에 관여하여 더 심화된 대기질 저하에 기인하고 있다. 이처럼 자동차에서 배출되는 탄화수소류에 포함되어 있는 VOCs는 이러한 2차 오염물질로 생성되는 성분중 오존에 긴밀히 관여하여 인체 등에 미치는 영향이 크기 때문에 VOCs 저감을 위한 여러 가지 방안들이 고려되고 있다. (중략)

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2000.11a
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• pp.197-199
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• 2000

오존은 배출원에서 직접 배출되는 1차 오염물질이 전구물질들이 강한 태양광선에 의해 광화학 반응을 일으켜 생성되는 2차 광화학 오염물질이다. 대표적인 전구물질로는 질소산화물(NOx)과 휘발성유기화합물(VOC)이다. 이러한 전구물질들은 화석연료의 연소와 자동차에서 직접 배출되어 대기 중에서 복잡한 물리ㆍ화학과정을 통하여 오존을 생성한다. 최근에 도심 지역 및 주변지역 그리고 몇몇 시골지역에서 발생하고 있는 오존의 고농도 현상은 중요한 대기오염 문제중의 하나로 부각되고 있다. (중략)

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2002.04a
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• pp.267-268
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• 2002

최근의 서울과 인근 수도권지역을 비롯하여 공장이 밀집되어 있는 산업도시나 교통량이 많은 대도시 지역에서 고농도의 오존이 종종 측정되고 있다. 일반적으로 대기중에 VOCs가 존재하지 않을 때 자연적으로 오존은 생성ㆍ소멸을 반복하여 순환하면서 일정한 농도를 유지하지만 오존생성 전구물질인 질소산화물(NOx), 휘발성유기화합물(VOCs)이 자외선을 흡수하여 산화되면서 오존의 농도를 증가시키는 것으로 알려져 있다. (중략)

• Proceedings of the KSME Conference
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• 2001.06d
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• pp.115-120
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• 2001

The present study examined the possibility of $NO_{x}$ reduction in the high temperature industrial furnaces. duct burner of gas turbine cogeneration and two-stage gas turbine combustor. The experimental study was carried out for the diffusion flame of second stage combustor with the variations of oxygen concentration and supplying rate of hot exhaust gas from first stage combustor. It also examined the flammability range and $NO_{x}$ formation of the second stage combustor in which the fuel is supplying into the mixture of oxygen hot exhaust gas from first stage combustor. The results show that the enrichment of oxygen and increase of exhaust gas lead to increase the $NO_{x}$ up to 50 ppm with 23% $O_{2}$ condition.