• 한국태양에너지학회 논문집
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• 제29권5호
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• pp.45-52
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• 2009

Fossil power plants firing lower grade coals or equipped with modified system for $NO_x$ controls are challenged with maintaining good combustion conditions while maximizing generation and minimizing emissions. In many cases significant derate, availability losses and increase in unburned carbon levels can be attributed to poor combustion conditions as a result of poorly controlled local fuel and air distribution within the boiler furnace. In order to develop a on-line combustion tuning system, field test was conducted at operating power boiler. During the field test the exhaust gases' $O_2,\;NO_x$ and CO was monitored by using a spatially distributed monitoring grid located in the boiler's high temperature vestibule and upper convective rear pass region. At these locations, the flue gas flow is still significantly stratified, and air in-leakage is minimal which enables tracing of poor combustion zones to specific burners and over-fire air ports. using these monitored information we can improving combustion at every point within the furnace, therefore the boiler can operate at reduced excess $O_2$ and gas temperature deviation, reduced furnace exit gas temperature levels while also reducing localized hot spots, corrosive gas conditions, slag or clinker formation and UBC. Benefits include improving efficiency, reducing $NO_x$ emissions, increasing output and maximizing availability. Discussion concerning the reduction of greenhouse gases is prevalent in the world. When taking a practical approach to addressing this problem, the best way and short-term solution to reduce greenhouse gases on coal-fired power plants is to improve efficiency. From this point of view the real time optimized combustion tuning approach is the most effective and implemented with minimal cost.

• 공업화학
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• 제21권3호
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• pp.243-251
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• 2010

연소배가스에 존재하는 질소산화물의 제거를 위해서는 촉매 환원, 흡수, 흡착 등 화학적 기술이 적용되고 있는데, 장기적으로는 환경친화적이고 에너지 소모가 적은 생물학적 공정의 개발 및 이용이 필요하다. 본 논문에서는 연소 배가스에 존재하는 질소산화물을 제거하기 위한 생물학적 공정의 기술동향을 살펴보고 각각의 장단점을 고찰하였다. 질산화와 탈질 기작을 이용하는 박테리아 시스템과 광합성 미세조류를 이용하는 시스템으로 구분하여 기술의 원리와 현재의 기술 수준을 논하였다. 두 경우 모두 처리속도를 높이기 위해서는 불용성의 일산화질소를 일단 적절한 흡수제에 고농도로 포집시킨 후 미생물에 의하여 분해 또는 고정하는 방향이 바람직하며, 배가스 중 $CO_2$와 NOx를 동시에 고정이 가능하고 별도의 탄소원이 요구되지 않는 미세조류의 활용이 기대된다.

• Environmental Engineering Research
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• 제19권4호
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• pp.299-308
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• 2014

This study presents a review on Chemical looping combustion (CLC) development, design aspects and modeling. The CLC is in fact an unmixed combustion based on the transfer of oxygen to the fuel by a solid oxygen carrier material avoiding the direct contact between air and fuel. The CLC process is considered as a very promising combustion technology for power plants and chemical industries due to its inherent capability of $CO_2$ capturing, which avoids extra separation costs of the of $CO_2$ from the rest of flue gases. This review covers the issues related to oxygen carrier materials. The modeling works are reviewed and different aspects of modeling are considered, as well. The main drawbacks and future research and prospects are remarked.

• 한국연소학회:학술대회논문집
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• 대한연소학회 2003년도 제27회 KOSCO SYMPOSIUM 논문집
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• pp.89-94
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• 2003

For the development of high efficiency and low emission combustion systems, high temperature air combustion technology has been tested by utilizing preheated air over 1100 K and exhaust gas recirculation. In this system, combustion air is diluted with large amount of exhaust gases ($N_2$, $CO_2$), such that the oxygen concentration is relatively low in the reaction zone, leading to low flame temperature. Since, the temperature fluctuations and sound emissions form the flame are small and flame luminosity is low, the combustion mode is expected to be flameless or mild combustion. Experiment was performed to investigate the turbulent flame structure and $NO_X$ emission characteristics in the high temperature air combustion focused on coflowing jet diffusion flames which has a fundamental structure of many practical combustion systems. The effect of turbulence has also been evaluated by installing perforated plate in the oxidizer inlet nozzle. LPG was used as a fuel. Results showed that even though $NO_X$ emission is sensitive to the combustion air temperature, the present high temperature air combustion system produce low $NO_X$ emission because it is operated in low oxygen concentration condition in excess of dilution.

• 대한기계학회논문집B
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• 제28권3호
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• pp.359-364
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• 2004

For the development of high efficiency and low emission combustion systems, high temperature air combustion technology has been tested by utilizing preheated air over 1100 K and exhaust gas recirculation. In this system, combustion air is diluted with large amount of recirculated exhaust gases, such that the oxygen concentration is relatively low in the reaction zone, leading to low flame temperature. Since, the temperature fluctuations and sound emissions from the flame are small and flame luminosity is low, the combustion mode is expected to be flameless or mild combustion. Experiment was performed to investigate the turbulent flame structure and NO$_x$ emission characteristics in the high temperature air combustion focused on coflowing jet diffusion flames which has a fundamental structure of many practical combustion systems. The effect of turbulence has also been evaluated by installing perforated plate in the oxidizer inlet nozzle. LPG was used as a fuel. Results showed that even though NO$_x$ emission is sensitive to the combustion air temperature, the present high temperature air combustion system produce low NO$_x$ emission because it is operated in low oxygen concentration condition by the high exhaust gas recirculation.

• 한국대기환경학회:학술대회논문집
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• 한국대기환경학회 2001년도 추계학술대회 논문집
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• pp.103-108
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• 2001

각종 연소기반의 오염 배출원에서의 수은을 비롯한 중금속의 배출은 많은 우려를 낳고있다. 이미 미국에서는 1990년 Clean Air Act Amendments를 통해 11개의 중금속의 (As, Be, Cd, Co, Cr, Hg, Mn, Ni, Pb, Sb, and Se) 배출을 가장 효과적인 적용 가능한 기술로서 그 배출을 제어하도록 되어있다. 그 중에서도 특히 수은은 다른 중금속과는 달리 높은 휘발성, 강한 유해성, 그리고 체내에 축적이 되는 특성으로 해서 더욱 관심의 대상이 되고 있다. 또한 수은은 연소장치에서 대기중으로 배출시 다른 중금속이 입자의 형태로 배출되는 것과는 달리 주로 원소상태의 기체로 배출되는 것으로 알려져 있다. (중략)

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 E
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• pp.1794-1796
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• 1998

In this study, the $SO_2$ addition effect on NOx removal has been conducted from a combustion flue gases by the do corona discharge-activated radical shower systems. The simulated flue gases were consisted of NO-O_2-$N_2$, NO-$CO_2-N_2-O_2$ and $NO-SO_2-CO_2-Na-O_2$([NO]o:200ppm and $[SO_2]o$:800ppm). The injection gases used as radical source gases were $NH_3$-Ar-air. $SO_2$ and NOx removal efficiency and the other by-products were measured by Fourier Transform Infrared(FTIR) as well as $SO_2$. NOx and $NO_2$ gas detectors. By-product aerosol particles were also observed by Condensation Nucleation Particle Counter(CNPC) and SEM images after sampling. The results showed that asignificant aerosol Particle formation was observed during a removal operation in corona radical shower systems. The NOx removal efficiency significantly increased with increasing applied voltage and $NH_3$ molecule ratio. The $SO_2$ removal efficiency was not significantly effected by applied voltage and slightly increased with increasing $NH_3$ molecule ratio. The NOx removal efficiency for NO-$SO_2-CO_2-N_2-O_2$ was better than that for NO-$CO_2-N_2-O_2$.

• 대한기계학회논문집B
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• 제28권1호
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• pp.9-15
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• 2004

$CO_2$ is a well-known green house gas as well as the major source of global warming. Many researchers have studied to reduce $CO_2$ emission in combustion processes. Among the method for reducing $CO_2$ emission, oxygen-enriched combustion has been proposed. Because its adiabatic flame temperature is relatively too high, existing facilities must be changed or the flame temperature in the combustion zone should be reduced. The combustion characteristics, composition in the flame zone, temperature profile and emission gases were investigated experimentally for the various oxygen-enriched ratios(OER) by the addition of $CO_2$, under constant $O_2$ flow rate. Results showed that the reaction zone was quenched and broadened as the addition of $CO_2$ was increased. The emission of NOx in flue gas was decreased as decreasing temperature in reaction zone. It was also shown that the reaction was delayed by the cooling effect. As the addition of $CO_2$ was increased, the composition of CO in the flame zone was increased due to the increase of reaction rate by increasing mixing effect of oxidant/fuel at OER=0％, but the composition of CO was decreased by quenching effect at OER=50％ and 100％.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 춘계학술대회
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• pp.1389-1394
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• 2003

$CO_2$ is a well-known green house gas, which is the major source of global warming. Many researchers have studied to reduce $CO_2$ emission in combustion processes. Among the method for reducing $CO_2$ emission, oxygen-enriched combustion has been proposed. But the adiabatic flame temperature is too high. So existing facilities must be changed, or the adiabatic flame temperature in the combustion zone should be reduced. The combustion characteristics, composition in the flame zone, temperature profile and emission gases were studied experimentally for the various oxygen-enriched mtios(OER) by addition of $CO_2$ under coustant $O_2$ flowrate. Results showed that the reaction zone was quenched, broadened, as addition of $CO_2$ was increased. Temperature has a large effect on the NOx emission. The emission of NOx in flue gas decreased due to the decreased temperature of reaction zone. It was also shown that the reaction was delayed by the cooling effect. As the addition of $CO_2$ was increased, the composition of CO in the flame zone increased due to the increase of reaction rate by increasing mixing effect of oxidant/fuel at OER=0, but the composition of CO decreased by quenching effect at OER=50 and 100%.

• Environmental Engineering Research
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• 제12권2호
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• pp.55-63
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• 2007

PCDD/Fs monitoring was carried out to estimate the contamination level in soil samples taken in the vicinity of the various incinerators throughout South Korea from July 2003 to December 2004. The levels ranged from N.D. to 130.39 pg I-TEQ/g (d.w.) with an average concentration of 11.38 pg I-TEQ/g (d.w.). The level of PCDD/Fs in this study is similar to that of other countries. Overall, the highest mean concentration in the soil was found at 250 m from the stack. In addition, the flue gases were analyzed in order to obtain the congener profiles of the PCDD/Fs emitted from the incinerators. The concentration of I-TEQ in the flue gas ranged from 0.33 to 21.5 ng TEQ/$Sm^3$. These levels were much lower than the concentration stipulated in the Korean emission criterion(40 ng TEQ/$Sm^3$ until 2005). The comparison of the congener patterns using cluster analysis showed that the incinerators and PCP are sources of PCDD/Fs in the soil samples according to the sampling point, but the possibility of unidentified combustion sources and vehicles exists in the case of complex industrial regions.