• Title/Summary/Keyword: Combustion Emission

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A Study on Dependence of Smoke Emission in Diesel Engines Upon Diffusion Combustion (디젤기관의 스모크배출의 확산연소 의존성에 관한 연구)

  • 한성빈;문성수;이성열
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.18 no.2
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    • pp.397-404
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    • 1994
  • Smoke is emitted in diesel engines because fuel injected into the high-temperatured and high-pressured combustion chamber burns with its mixture with insufficient oxygeny. In consideration of air pollution, above all, it is necessary to illuminate the cause of smoke emission in diesel engines. The smoke emission, which is characteristic of diffusion combustion in diesel engines, results from pyrolysis of fuel not mixed with air. Therefore the smoke emission is dependent on diffusion combustion quantity, which is in turn controlled by engine parameter. The study aims at making clear and interpreting the interdependence of smoke emission in diesel engines with heat released within combustion chamber, camparing diffusion combustion quantity according to each engine parameter (air fuel ratio, injection timing, and engine speed), and showing the relation between smoke emission and fraction of diffusion combustion through experiment.

A Study on Low Emission Pulverized Coal Combustion in the 2 Staged Coaxial Cyclone Combustor (2단 동축형 Cyclone 연소기를 이용한 저공해 미분탄 연소특성 연구)

  • Choi, Sang-Il;Park, Chu-Sik;Kim, Sung-One;Kim, Ho-Young
    • Journal of the Korean Society of Combustion
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    • v.4 no.1
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    • pp.67-83
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    • 1999
  • The objective of this study is development of low emission pulverized coal combustor for reducing pollutant emission generated from coal combustion. Low emission combustion technology for reducing NOx and fly ash was investigated by using 2 stage coaxial cyclone combustor. Staged combustion was employed for NOx reduction and high temperature slagging combustion was also studied for fly ash removal in the combustor. The result of this study shows that the low emission combustion system can reduce the amount of atmospheric pollutions with improved boiler efficiency and performance.

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The Relationship Between Firing Modes and Nitric Oxide Emission In Highly Preheated Air Combustion

  • Choi, Gyung-Min;Katsuki, Masahi;Kim, Duck-Jool
    • Journal of Mechanical Science and Technology
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    • v.14 no.4
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    • pp.433-440
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    • 2000
  • The influence of combustion air at temperatures on nitric oxide emission was studied. The nitric oxide emission generally increases with a rise in the temperature of the combustion air. However, if combustion products for dilution of fuel or combustion air are used before the combustion reaction, then the nitric oxide emission can be reduced even when highly preheated air for combustion air is used. Combustion in low oxygen concentrations flattens the firing mode, resulting in a uniform reaction, and, thus, low nitric oxide emission can be achieved.

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Numerical Simulations for Combustion and NOx Emission Characteristics in Oscillating Combustion Burner (수치해석을 이용한 맥동연소과정 및 NOx 배출특성 해석)

  • Kim, Hoo-Joong;Cho, Han-Chang
    • Journal of the Korean Society of Combustion
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    • v.14 no.3
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    • pp.37-44
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    • 2009
  • An experimental study was conducted to reduce NOx emission in RT(radiant tube)burner by using oscillating combustion processes in RIST. A solenoid valve gives the various oscillating conditions, such as oscillation frequency, duty ratio of fuel flow. In this study, we used commercial software, CFD-ACE+ to predict combustion and NOx emission characteristics for various experimental oscillation conditions. The effect of oscillation frequency and duty ratio on NOx emission will be discussed in terms of flow field, temperature and equivalence ratio distributions in detail.

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A Study on the Reduction of NO Emission from a Diesel Engine with 2-Stage Type Combustion Chamber (2단 연소형 연소실을 갖는 디젤기관의 NO 저감에 관한 연구)

  • 진선호;배종욱
    • Journal of Advanced Marine Engineering and Technology
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    • v.26 no.5
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    • pp.554-564
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    • 2002
  • A newly designed combustion chamber of diesel engine with a modified piston crown was prepared for the purpose of investigation for reduction of NO emission. It was intended to realize 2-stage combustion that is to keep fuel rich condition during early stage of combustion and fuel lean condition during next stage. The engine was tested on various conditions concerning exhaust gas emissions especially about NO emission and simultaneously fuel consumption rate. It was found that the engine with 2-stage combustion type piston emits significantly low NO at various speed and torque compared with conventional engines, but it raised points at issue in CO and smoke emissions with fuel consumption rate. The increasing of injection pressure on 2 stage combustion type diesel engine affects on CO and smoke emission considerably to reduce but slightly on NO to increase. The effect of 2-stage combustion was better at low speed than at high speed.

Study on Characteristics of Catalytically Supported Thermal Combustion for Gas Turbine (가스터어빈용 촉매연소기를 위한 촉매-화염 복합 연소 특성연구)

  • Lee, Kyung-Wong;Chung, Nam-Jo;Ryu, In-Soo;Cho, Sung-June;Kang, Sung-Kyu;Chun, Kwang-Min;Song, Kwang-Sup
    • 한국연소학회:학술대회논문집
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    • 2001.11a
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    • pp.73-82
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    • 2001
  • The characteristics of the catalytically supported thermal combustion with Pd-based catalyst using the bench scale high pressure combustor has been investigated up to 7 atm. The emission of $NO_{\chi}$ depends on the preheating temperature and the excess air ratio. Most $NO_{\chi}$ emission seems to come from the pre-burner for the preheating of the inlet gas. Decreasing excess air ratio in the inlet gas below 1.5 results in the stable catalytically supported thermal combustion in the post combustion region while the $NO_{\chi}$ emission increased up to 15 ppm. Further, the increase of the pressure shows the dramatic increase of the emission CO and THC. However, the $NO_{\chi}$ emission decreased slightly due to the lower combustion temperature at the high pressure.

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Effect of Premixing Condition on the Combustion and Emission Characteristics of HCCI Diesel Engine (균일 예혼합 압축 착화 디젤 엔진의 예혼합 조건 변화에 따른 연소 및 배기 특성)

  • Kim, Myung-Yoon;Hwang, Seok-Jun;Kim, Dae-Sik;Lee, Ki-Hyung;Lee, Chang-Sik
    • 한국연소학회:학술대회논문집
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    • 2003.05a
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    • pp.7-12
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    • 2003
  • The purpose of this work is to investigate the effect of premixing condition on the combustion and exhaust emission characteristics in a HCCI diesel engine. To form homogeneous charge before intake manifold, the premixed fuel is injected into premixed tank by GDI injection system and the premixed fuel is ignited by direct injected diesel fuel. But in the case of high intake air temperature, premixed fuel is auto-ignited before diesel combustion and soot emission is increased. In the case of light load condition, the BSFC is improved by intake air heating because increased air temperature promoted the combustion of premixed mixture. NOx and smoke concentration of exhaust emissions are reduced compared to conventional diesel engine. The combustion characteristics of the HCCI diesel engine such as combustion pressure, rate of heat release, and exhaust emission characteristics are discussed.

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Low NOx MILD Combustion for Sawdust Fuel (폐목 톱밥 연료의 저NOx MILD연소)

  • Shim, Sung-Hoon
    • 한국신재생에너지학회:학술대회논문집
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    • 2008.10a
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    • pp.153-156
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    • 2008
  • MILD combustion has been successfully applied to gaseous fuels and few commercial systems are now in operation. Extending MILD combustion applicability to solid fuel of sawdust is the focus of the present work. The MILD combustion furnace at the University of Adelaide in Australia was used in this study. A measurement of $O_2$ and CO emissions have been carried out in parallel with consideration of NOx emission and compared in each modes of conventional natural gas combustion, natural gas MILD combustion, NOx emission in natural gas MILD combustion mode can be reduced to 20% in comparison with conventional combustion. Emission in cases of air carrying sawdust combustion and $CO_2$ carrying sawdust combustion were also compared. Air and $CO_2$ were sued as a carry gas for the sawdust. It was found that MILD conditions are possible for sawdust particles of less than $355{\mu}m$ without additional air pre-heating. It was also found that when using $CO_2$ as the carry gas the flame inside the furnace was not visible anymore and that NOx emission dropped to less than two folds.

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An Experimental Study of the Characteristics with High Temperature Air Combustion in Jet Diffusion Flames (제트확산염의 고온공기연소특성에 관한 실험적 연구)

  • Cho, Eun-Seong;Ohno, Ken;Kobayashi, Hideaki;Chung, Suk-Ho
    • 한국연소학회:학술대회논문집
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    • 2003.12a
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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.

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Computational Study of the Mild Combustion and Pollutant Emission Characteristics in Wall-confined Jet (벽면으로 둘러싸인 제트 유동장에서의 마일드연소 및 오염물질 배출특성에 관한 전산해석 연구)

  • Song, Keum Mi;Oh, Chang Bo
    • 한국연소학회:학술대회논문집
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    • 2012.04a
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    • pp.263-266
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    • 2012
  • The characteristics of mild combustion and pollutant emission were investigated computationally with supplied air stream temperature and dilution rate in jet flame. The air was diluted with main combustion products. As dilution rate increased at fixed air temperature, the temperature distribution of burner inside was uniformed and the maximum mole fraction of CO and NO was decreased. In addition, emission indices for NO, CO, and $CO_2$ were compared with air temperature and dilution rate.

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