• Journal of the Korean Institute of Gas
• /
• v.23 no.6
• /
• pp.8-16
• /
• 2019

One of the methods for low-pollution combustion, flue gas recirculation(FGR) is effective to reduce nitrogen oxides and it was applied in CH₄/air premixed counterflow flames to identify the change of flame characteristics and NOx mechanisms. Considering that the mole fraction of the products varied depending on the strain rates, the major products: CO₂, H₂O, O₂ and N₂ were recirculated as a diluent to reflect the actual combustion system. With the application of the FGR technique, a turning point of maximum flame temperature under certain strain rate condition was found. Furthermore as the recirculation ratio increased, the tendency of NO was changed before and after the turning point and the analysis on thermal NO and Fenimore NO production was conducted.

• Proceedings of the Korea Air Pollution Research Association Conference
• /
• 2003.05b
• /
• pp.217-218
• /
• 2003

오늘날 대기환경에 존재하는 여러 오염물질 중에서 오존의 생성과 밀접한 관련이 있는 질소산화물과 휘발성유기화합물 (volatile organic compound, VOC)의 대기 환경학적 역할의 중요성이 점차 부각되고 있다 (Liu et al., 2000. VOC는 비록 대기 중에 극미량 농도로 존재하지만, 이들 성분이 대기환경의 변화에 미치는 잠재적 영향력은 가늠하기 어려울 정도로 막대하다. 지금까지 도심환경에 대한 VOC 성분의 분포특성을 설명하기 위해, 주요 인위적 기원의 VOC 성분들의 주구성인자로 간주할 수 있는 benzene, toluene, ethyl benzene, xylene (일반적으로 이들을 총칭하여 BTEX라 한다)을 위시한 방향족 화합물의 핵심성분들에 대한 환경거동 및 단주기적 분포특성에 대한 관측이 많은 연구자들에 의해 수행되었다(eg., Keymeulen et al., 2001). (중략)

• Journal of the Korean Society of Combustion
• /
• v.4 no.1
• /
• pp.59-65
• /
• 1999

Ignition of $NH_3-O_2-Ar$ mixtures have been studied behind reflected shock waves over the temperature range of 1600-2300 K and the pressures in the range of 1.1-1.6 atm. The pressure profile and the radiation emitted behind the shock waves have been monitored to give empirical correlations between ignition delay times and the mixture concentrations with the experimental conditions. On the basis of this data, several kinetic mechanisms proposed for ammonia oxidation at high temperatures have been tested. The ignition delay times obtained from the mechanism proposed by Miller and Smook were in good agreement with our experimental results.

• Journal of the Korean Society of Combustion
• /
• v.4 no.1
• /
• pp.131-139
• /
• 1999

A Numerical Analysis of NOx production in Hydrogen-Air flame is performed using the quasi-laminar reaction modelling. As results, in low global strain rate region, $U_F/D_F\;{\leq}\;50,000$, the quasi-laminar reaction modelling reproduces the experimentally observed EINOx half power scaling that the ratio of EINOx and flame residence time, $L_f^3(D_F^2U_F)$, is proportional to the square root of global strain rate. Thus, it suggests that turbulence-chemistry interaction has a minor impact on the trend of NOx production in low global strain rate region. However, the quasi-laminar reaction modelling predicts the higher temperature and NOx than experimentally observed. This overprediction may be due to the lack of radiation and quasi-laminar reaction modelling.

• 한국연소학회:학술대회논문집
• /
• 1999.10a
• /
• pp.1-9
• /
• 1999

The NOx production and combustion characteristics are experimentally compared with an offset with counter-orifice configuration. The offset-opposed impinging flame creates stronger vortex around the stagnation point than the opposed flame. The thermal and mass mixtures be improved and the delay of turbulence dissipation be occurred by the strong vortex. In result, the turbulent flame structure transferred from the wrinkled flame and the corrugated flame to the distributed reaction flame. It was found that the offset-opposed impinging flame decreased more NOx and improved the combustion efficiency than the opposed flame. The principal objective of this study is to develop the low NOx combustor by distributed reaction flame.

• Journal of the Korean Society of Combustion
• /
• v.13 no.1
• /
• pp.10-16
• /
• 2008

Numerical simulations of freely propagating premixed flames burning mixtures of methane and chlorinated hydrocarbons in fuel are performed at atmospheric pressure in order to understand the effect of chlorinated hydrocarbons on the formation of nitrogen oxide. A detailed chemical reaction mechanism is used, the adopted scheme involving 89 gas-phase species and 1017 elementary forward reaction steps. Chlorine atoms available from chlorinated hydrocarbons inhibit the formation of nitrogen oxides by lowering the concentration of radical species. The reduction of NO emission index calculated with thermal or prompt NO mechanism is not linear and is probably related to the saturation effect as $CH_3Cl$ addition is increased, In the formation or consumption of nitrogen oxide, the $NO_2$ and NOCl reactions play an important role in lean flames while the HNO reactions do in rich flames. The molar ratio of Cl to H in fuel has an effect on the magnitude of NO emission index.

• Journal of Ocean Engineering and Technology
• /
• v.13 no.3B
• /
• pp.22-28
• /
• 1999

The purpose of this study is to investigate the NOx emission of turbulent diffusion flame formed in the after burner, which is located on the waste gas coming out from the test furnace. Three types of flame was tested and each of which was changed by adequate equivalence ratio. It is necessary to study more about NOx reduction effect in the after burner system.

• Proceedings of the KSME Conference
• /
• 2001.11b
• /
• pp.102-105
• /
• 2001

Numerical simulations of coal combustion were carried out to identify what kind of burner design parameters are affecting the NOx emission. Where used burner design parameters are primary air velocity, secondary air velocity, $2^{nd}/3^{rd}$ air ratio, tertiary air velocity, and tertiary air injection location. Taguchi method was used to find the effective burner design parameters related to NOx formation. The results of numerical simulations showed that secondary air velocity and $2^{nd}/3^{rd}$ air ratio was the key parameters reducing the NOx emission. The total number of simulation cases was reduced by Taguchi method.

• Proceedings of the Korea Air Pollution Research Association Conference
• /
• 2000.04a
• /
• pp.151-152
• /
• 2000

광양만권역은 석유화학산업과 제철공업등 대규모 공단에서 배출되는 질소산화물, 탄화수소류에 의한 오존 농도가 증가되고 있으며, 산성비 등의 2차 오염생성물질에 의한 광역지역의 대기오염 현상도 이들의 물질들이 깊이 관여하고 있다. 따라서, 광양만권의 대기질 개선을 위해서는 대기오염물질의 배출원 및 배출량 분포를 정확하고 세밀한 파악이 무엇보다도 중요하다. 따라서, 본 연구에서는 광양만권의 광화학 옥시단트(Ox) 예측모델의 개발에 사용될 오염물질 배출량을 고정발생량 및 이동발생량으로 구분하 산출하였다. (중략)

• Proceedings of the Korea Air Pollution Research Association Conference
• /
• 2000.04a
• /
• pp.174-175
• /
• 2000

대기오염은 화석연료를 사용한 산업혁명 이후에 본격적으로 나타난 현상이다. 특히, 중공업을 중심으로 하는 고도 성장기에는 대기오염물질의 배출이 급격히 증가하였으며, 인구집중이 심한 도시와 도시근교서의 대기오염은 사회문제로 대두되었다. 최근에는 산성비 및 온난화와 같은 지구규모의 환경문제로 발전되고 있다. 그 중에서 질소산화물(NOx)과 탄화수소(HC)에 의한 도시 대기오염은 점점 증가하는 추세이며, 특히, 광화학 옥시던트(Ox)는 발생 메카니즘이 복잡하며, 발생원과 오염지역과의 상호 연관성 파악이 어렵기 때문에 지금까지 대부분 환경평가 대상에서 제외되었으나, 향후의 환경 정책문제로 수용되고 있는 추세이다. (중략)