• Title, Summary, Keyword: Exhaust gas temperature

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Comparative Part Load Performance Analysis of Gas Turbine Power Generation Systems Considering Exhaust Heat Utilization (배열 이용도를 고려한 가스터빈 발전시스템의 부분부하 성능 비교분석)

  • Kim, T. S.
    • 유체기계공업학회:학술대회논문집
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    • pp.290-297
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    • 2002
  • This paper presents analysis results for the effect of power control strategies on the part load performance of gas turbine based power generation systems utilizing exhaust heat of the gas turbine such as cumbined cycle power plants and regenerative gas turbines. For the combined cycle, part load efficiency variations were compared among different single shaft gas turbines representing various technology levels. Power control strategies considered were fuel only control and IGV control. It has been observed that gas turbines with higher design performances exhibit superior part load performances. Improvement of part load efficiency by adopting air flow modulation was analyzed and it is concluded that since the average combined cycle performance is affected by the range of IGV control as well as its temperature control principle, a control strategy appropriate for the load characteristics of the individual plant should be adopted. For the regenerative gas turbine, it is likewise concluded that maintaining exhaust temperature as high as possible by air flow rate modulation is required to increase part load efficiency.

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Exhaust Gas Temperature and Combustion Stability Variation due to Changes in Spark and Exhaust Valve Timings (스파크 점화기관의 냉시동시 배기밸브 타이밍 및 점화시기 변화에 따른 배기가스 온도 및 연소안정성의 변화)

  • Kim Duksang;Park Youngjoon;Yang Changsuck;Cho Yong-Seok
    • Transactions of the Korean Society of Automotive Engineers
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    • v.13 no.4
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    • pp.90-96
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    • 2005
  • The improvement of combustion stability is very important because it is closely related to the exhaust emission concentrations as well as the fuel consumption during the cold start of SI engine. In our previous studies, the spark and exhaust valve timings were retarded individually from the baseline case to increase the exhaust gas temperature far fast warmup of a close-coupled catalyst. In the study, it was found that combustion stability during cold start becomes worse when the valve timing is retarded from the baseline conditions. The spark and valve timings were simultaneously changed from the baseline conditions to find out the variation of combustion stability during cold start of an Sl engine. Through the study. retarded spark timing by $5^{\circ}$ CA helps improvement of $COV_{imep}$ by $2\%$ and $15^{\circ}C$ increase of exhaust temperature. Retarded exhaust valve timing makes the exhaust gas temperature increase by $30^{\circ}C$, but it also deteriorates the $COV_{imep}$ by $1\%$.

Structural Safety Evaluation of a 3-way Damper Valve for Scrubber-linked Exhaust Gas Control (스크러버 연계 배기가스 배출제어용 3방향 댐퍼밸브의 구조 안전성 평가)

  • Kim, Young-Hun
    • Journal of the Korean Society of Industry Convergence
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    • v.23 no.6_2
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    • pp.1007-1014
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    • 2020
  • IMO(International Maritime Organization) continues to strengthen environmental regulations on exhaust gases such as CO2, NOx, SOx. As for sulfur oxides, from 1 January 2020, all ships on international voyages must use fuel with a sulfur content of 0.5% or less. Or, it is obligatory to use an exhaust gas treatment device that has the same effect. Shipping companies are using low-sulfur oil, replacing them with LNG fuel, or installing scrubbers that suppress sulfur oxide emissions. In the case of ships using bunker C oil, the load on the engine is lower when entering and departing, so the exhaust gas pressure is lowered and the scrubber cannot be properly utilized. Therefore, diesel oil with low sulfur content is used when entering and leaving the coast. When diesel oil is used, exhaust gas is directly discharged through the control system and piping system, and when bunker C oil is used, sulfur oxides are reduced by scrubbers through other control systems and piping systems to discharge exhaust gas. Accordingly, a company has developed a system called a three-way damper valve that can control exhaust gas emissions while integrating these two control systems and piping systems into one. In this study, the control characteristics of the integrated exhaust gas control system and structural safety against external loads in a high-temperature exhaust gas environment were reviewed.

HEAT PIPE TYPE EXHAUST HEAT RECOVERY SYSTEM FOR HOT AIR HEATER

  • Kang, G.C.;Kim, Y.J.;Ryou, Y.S.;Rhee, K.J.
    • Proceedings of the Korean Society for Agricultural Machinery Conference
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    • pp.654-661
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    • 2000
  • Area of greenhouse increases rapidly up to 45,265ha by the year of 1998 in Korea. Hot air heater with light oil combustion is the most common heater for greenhouse heating in the winter season. However, exhaust gas heat discharged to atmosphere through chimney reaches up to 10~20% of total heat of the oil combusted in the furnace. In order to recapture the heat of this exhaust gas and to recycle for greenhouse heating, the heat pipe type exhaust heat recovery system was manufactured and tested in this experiment. The exhaust heat recovery system was made for space heating in the greenhouse. The system consisted of a heat exchanger made of heat pipes, ${\emptyset}15.88{\times}600mm$ located in the rectangular box of $600{\times}550{\times}330mm$, a blower and air ducts. The rectangular box was divided by two compartments where hot chamber exposed to exhaust gas in which heat pipes could pick up the heat of exhaust gas, and by evaporation of the heat transfer medium in the pipes it carries the heat to the cold compartment, then the blower moves the heat to greenhouse. The number of heat pipe was 60, calculated considering the heat exchange amount between flue gas and heat transfer capacity of heat pipe. The working fluid of heat pipe was acetone because acetone is known for its excellent heat transfer capacity. The system was attached to the exhaust gas path. According to the performance test it could recover 53,809 to 74,613kJ/hr depending on the inlet air temperature of 12 to $-12^{circ}C$ respectively when air flow rate $1,100\textrm{m}^3/hr$. The exhaust gas temperature left the heat exchanger dropped to $100^{circ}C$ from $270^{circ}C$ by the heat exchange between the air and the flue gas, the temperature difference was collected by the air and the warm air temperature was about $60^{circ}C$ at the air flow rate of $1,100\textrm{m}^3/hr$. This heat pipe type exhaust heat recovery system can reduce fuel cost by 10% annually according to the economic analysis.

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A Study on Effect of Environmental Characteristics by Intake Mixture Temperature in Scrubber EGR System Diesel Engines

  • Bae, Myung-Whan;Ryu, Chang-Sung
    • Proceedings of the Korean Society Of Semiconductor Equipment Technology
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    • pp.100-111
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    • 2002
  • The effects of intake mixture temperature on performance and exhaust emissions under four kinds of engine loads were experimentally investigated by using a four-cycle, four-cylinder, swirl chamber type, water-cooled diesel engine with scrubber EGR system operating at three kinds of engine speeds. The purpose of this study is to develop the scrubber exhaust gas recirculation(EGR) control system for reducing $NO_x$ and soot emissions simultaneously in diesel engines. The EGR system is used to reduce $NO_x$ emissions. And a novel diesel soot-removal device of cylinder-type scrubber with five water injection nozzles is specially designed and manufactured to reduce soot contents in the recirculated exhaust gas to the intake system of the engine. The influences of cooled EGR and water injection, however, would be included within those of scrubber EGR system. In order to survey the effect of intake mixture temperature on performance and exhaust emissions, the intake mixtures of fresh air and recirculated exhaust gas are heated by a heating device with five heating coils made of a steel drum. It is found that the specific fuel consumption rate is considerably elevated by the increase of intake mixture temperature, and that $NO_x$ emissions are markedly decreased as EGR rates are increased and intake mixture temperature is dropped, while soot emissions are increased with increasing EGR rates and intake mixture temperature. Thus one can conclude that the performance and exhaust emissions are considerably influenced by the cooled EGR.

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Study on Emission Characteristics in a Hydrogen-fueled Engine (수소기관에서의 배기가스에 관한 연구)

  • Cho, U.L.;Ghoi, G.H.;Bae, S.C.
    • Transactions of the Korean hydrogen and new energy society
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    • v.13 no.1
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    • pp.83-89
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    • 2002
  • The goal of this research is to understand the NOx emission in direct injected diesel engine with premixed hydrogen fuel. Hydrogen fuel was supplied into the test engine through the intake pipe. Amount of hydrogen-supplemented fuel was 70 % basis on heating value of the total input fuel. The effects of intake air temperature and exhaust gas recirculation(EGR) on NOx emission were studied. The intake air temperatures were varied from $23^{\circ}C$ to $0^{\circ}C$ by using liquid nitrogen. Also, the exhaust gas was recirculated to the intake manifold and the amount of exhaust gas was controlled by the valve. The major conclusions of this work include: ( i ) nitrogen concentrations in the intake pipe were increased by 30% and cylinder gas temperature was decreased by 24% as the intake air temperature were changed from $23^{\circ}C$ to $0^{\circ}C$; ( ii ) NOx emission per unit heating value of supplied fuel was decreased by 45% with same decrease of intake air temperature; and (iii) NOx emission was decreased by 77% with 30% of EGR ratio. Therefore, it may be concluded that EGR is effective method to lower NOx emission in hydrogen fueled engine.

Numerical Study for the Effect of Engine Exhaust Gas on the Airframe of Smart UAV (스마트무인기 엔진 배기가스가 기체에 미치는 영향에 관한 수치적 연구)

  • Lee, Chang-Ho;Kim, Cheol-Wan;Kim, Jai-Moo
    • 한국전산유체공학회:학술대회논문집
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    • pp.464-467
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    • 2008
  • An ejector is designed for the purpose of engine bay cooling. The primary flow of the ejector is the exhaust gas of the PW206C turboshaft engine. The mass flow of secondary flow is calculated by using the approximate analytic equation. And the effect of exhaust gas flow on the fuselage surface is investigated by using the Fluent Code. Three types of exhaust duct shape were compared in the viewpoint of surface temperature and aerodynamic drag. As a result, exhaust duct shape P3 shows minimum interference of exhaust gas and fuselage and minimum increment of drag among the three candidate shapes.

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An Experimental Study on Spark Timing Effect for Fast warmup of Catalyst to Cold Start Operation of an SI Engine (가솔린기관의 냉시동시 촉매 가열 촉진을 위한 점화시기 영향에 대한 실험적 연구)

  • Kwon, Y.W.;Ham, S.H.
    • Journal of the Korean Society of Mechanical Technology
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    • v.13 no.4
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    • pp.101-108
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    • 2011
  • On cold start operation of an SI engine, a catalyst shows poor performance before it reaches activation temperature. Therefore, fast warmup of the catalyst is very crucial to reduce harmful emissions. In this study, an appropriate control strategy is investigated to increase exhaust gas temperature through changes of spark timing. Combustion stability is also considered at the same time. Exhaust gas temperature and pressure of combustion chamber are measured to investigate the effects of spark timings on cold start and idle performance. Experiments showed that retarded spark timing promotes the combustion at the end of expansion stroke and increases exhaust gas temperature during cold start.

A Study on the Reduction of HC and Heat Characteristics of the Dual Pipe Exhaust Manifold (이중관 배기메니폴드의 HC저감효과 및 열특성에 관한 연구)

  • 박경석;허형석
    • Transactions of the Korean Society of Automotive Engineers
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    • v.9 no.6
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    • pp.103-111
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    • 2001
  • During cold-start period, the reduction of exhaust emissions is a challenging task. To decrease harmful gaseous substances such as HC, it is necessary to realize a fast catalyst warm-up. In this study, the performance of dual pipe exhaust system have been carried out through different test mode. From measurement of gas temperature and HC concentration, the following conclusions were derived ; 1) Compared with single pipe, dual pipe exhaust system remarkably increase temperature of exhaust gas going through M.C.C(Main Catalytic Converter). 2) W.C.C.(Warm-up Catalytic Converter) also decreases HC emission. To reduce HC emission, it is helpful to use W.C.C. as well as dual pipe exhaust system. 3) Using finite element method, it is shown that inner parts have much higher distribution of temperature than outer parts.

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A Study on Effect of Intake Mixture Temperature upon Fuel Economy and Exhaust Emissions in Diesel Engines with a Scrubber EGR System

  • Bae, Myung--Whan;Ryu, Chang-Seong;Yoshihiro Mochimaru;Jeon, Hyo-Joong
    • Journal of Advanced Marine Engineering and Technology
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    • v.28 no.2
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    • pp.315-331
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    • 2004
  • The effects of intake mixture temperature on performance and exhaust emissions under four kinds of engine loads were experimentally investigated by using a four-cycle. four-cylinder. swirl chamber type. water-cooled diesel engine with scrubber EGR system operating at three kinds of engine speeds. The purpose of this study is to develop the scrubber exhaust gas Recirculation (EGR) control system for reducing $\textrm{NO}_{x}$ and soot emissions simultaneously in diesel engines. The EGR system is used to reduce $\textrm{NO}_{x}$ emissions. And a novel diesel soot-removal device of cylinder-type scrubber with five water injection nozzles is specially designed and manufactured to reduce soot contents in the recirculated exhaust gas to the intake system of the engine. The influences of cooled EGR and water injection. however. would be included within those of scrubber EGR system. In order to survey the effects of cooled EGR and moisture on $\textrm{NO}_{x}$ and soot emissions. the intake mixtures of fresh air and recirculated exhaust gas are heated up using a heater with five heating coils equipped in a steel drum. It is found that intake and exhaust oxygen concentrations are decreased, especially at higher loads. as EGR rate and intake mixture temperature are increased at the same conditions of engine speed and load. and that $\textrm{NO}_{x}$ emissions are decreased. while soot emissions are increased owing to the decrease in intake and exhaust oxygen concentrations and the increase in equivalence ratio. Thus ond can conclude that $\textrm{NO}_{x}$ and soot emissions are considerably influenced by the cooled EGR.