• Title, Summary, Keyword: 연소반응

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The Effect of Pyrolysis Pressure on Combustion Reactivity of Coal Char (열분해 압력이 석탄 촤의 연소반응성에 미치는 영향)

  • Park Ho Young;Kim Young Ju;Kim Tae Hyung;Seo Sang Il
    • Journal of Energy Engineering
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    • v.14 no.1
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    • pp.1-10
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    • 2005
  • The combustion reactivity of char depending on the pyrolysis pressure was investigated with Pressurized Thermogravimetric Analyser. The amounts of volatiles released at pyrolysis pressure of 1, 8 and 15 atm were, first, measured with Alaska, Adaro and Denisovsky coals. Reactivities of chars produced at var-ious pyrolysis pressure were evaluated at atmospheric pressure and 500℃, and analysed in terms of char crystal structure, surface area, pore characteristics and chemical composition of char. Finally, the combustion reactivities of three chars were examined at pressure of 1 atm, 8 atm and 15 atm. From this study, it was recognized that the amount of volatiles released decreases with increase in pyrolysis pressure, and reaction rate of char produced at higher pyrolysis pressure was lower than that at lower pyrolysis pressure. It might be resulted from the difference in char surface area and pore characteristics rather than char crystal structure and chemical characteristics. At 15 atm, kinetic parameters of Alaska char were obtained with the grain model, and these were 56.8 KJ/mole for activation energy and 222.34 (1/min) for frequency factor.

A Study of Combustion Reaction of Methane by Pd Catalyst - Effects of Support Size & Calcination Temperature - (팔라듐 촉매의 메탄의 연소반응에 관한 연구 -담체의 크기와 소성온도에 따른 효과-)

  • Lee Taeck Hong
    • Journal of the Korean Institute of Gas
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    • v.8 no.3
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    • pp.52-56
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    • 2004
  • Pd catalyst have been used in hydrogenation, oxidation, and low temperature combustion reaction. Recently, it is candidated as a possible reagents in the partial oxidation of methanol reformers of the fuel cell. Pd catalysts, even though it is very precious and expensive, catalytic functioning is good, but it still need to be improved in the matter of durability and low catalytic activity after calcination. In this study, we synthesize the improved Pd catalyst and study their chemical functioning.

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Analysis of Fuel Rod Behavior under Rod Ejection Accident (제어봉이탈사고시의 핵연료봉 거동 분석)

  • 이찬복;김오환;임익성;유호식;정진곤
    • Proceedings of the Korean Nuclear Society Conference
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    • pp.311-316
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    • 1996
  • 제어봉이탈사고시의 핵연료봉 거동을 연구로에서의 반응도사고 모사실험 결과와 기존의 핵연료 손상기준을 비교하여 분석하였다. 반응도사고시 고연소도 핵연료의 손상은 주로 PCMI 기구로 발생하는데, 고연소도에서의 피복관의 부식 및 수소화 그리고 방사선조사에 의한 연성감소와 산화층 박리로 인한 수소화합물의 국부적인 집중화로 인한 피복관의 현저한 연성감소가 주요 원인이었다. 기존의 핵연료 손상 기준에서 DNB가 일어날때 핵연료 손상이 발생한다는 가정은 낮은 핵연료엔탈피에서 핵연료 손상이 일어나는 것과 동일함을 확인하였으며, 현재까지 발표된 실험자료와 핵연료손상기구의 분석을 통해 연소도에 따른 반응도사고시의 핵연료손상기준을 예비적으로 유도하였다. 핵연료손상은 낮은 연소도에는 DNB로 발생하고 고연소도에서는 PCMI로 발생할수 있기 때문에, 과도상태에서의 고연소도 핵연료의 건전성 유지를 위해서는 피복관 산화층의 박리로 인한 수소화합물의 집중화로 피복관의 연성이 감소되는 것을 방지할 필요가 있다.

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Properties of Methane Steam Reforming in Micro Channel Reactor (미세유로 반응기를 이용한 메탄 스팀 개질 반응 특성)

  • Lee, Sung-Wook;Lee, Chun-Boo;Kim, Kwang-Ho;Park, Jin-Woo;Hwang, Kyung-Ran;Park, Jong-Soo;Kim, Sung Hyun
    • 한국신재생에너지학회:학술대회논문집
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    • pp.114.2-114.2
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    • 2010
  • 마이크로 반응기술은 작은 반응기 부피, 높은 열전달, 넓은 반응 면적/부피 및 정확한 반응시간 조절이 가능하기 때문에 화학공정의 고집적화, 반응 선택도의 향상 및 안전도 향상을 꾀할 수 있는 장점이 있다. 이러한 마이크로 반응 기술을 중소형 천연가스 및 국내에서 소규모로 국지적으로 발생하는 메탄의 활용 방안으로서 개발함은 청정 합성유를 제조함으로서 석유 자원의 고갈과 고유가에 대비하여 에너지 자원의 다변화 및 자립을 확보 할 수 있다. 본 연구에서는 마이크로 반응기술을 적용한 미세 유로 반응기(Micro Channel Reactor)를 사용하여 메탄 스팀 개질 반응 특성을 연구하였다. 미세유로 반응기는 내부 홀이 존재하는 plate를 적층함으로 반응기내에 반응가스가 이동할 수 있는 미세유로가 존재하게 하였다. 이러한 미세유로는 반응기의 크기가 작음에도 반응기내에서 반응가스가 충분히 반응할 수 있는 시간과 높은 열전달 효율을 가질 수 있게 한다. 메탄 스팀 개질 반응에 사용된 촉매는 Ni 촉매를 사용하였고, 반응에 필요한 열원으로는 수소 연소에서 발생한 열을 사용하여 반응을 유도하였다. 본 반응기는 외부의 열원을 사용하지 않고, 반응기 내부의 수소 연소에서 발생한 열을 사용함으로 적은 발생 열만으로 메탄 스팀 개질 반응에 필요한 에너지를 얻을 수 있고, 열의 손실이 적다. 또한 메탄 스팀 개질 반응으로 발생한 일부의 수소를 열원으로 이용하여 에너지 사용면에서도 효율적인 반응 공정이다.

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Characteristics of UBC and NOx Emission in Air Staging Combustion (공기 다단 연소 기법 적용에 따른 미연탄소분 및 질소산화물 배출특성)

  • Kim, Jeong Woo;Lim, Ho;Go, Young Gun;Jeon, Chung Hwan
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.40 no.10
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    • pp.637-644
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    • 2016
  • The purpose of this study is to understand the characteristics of unburned carbon (UBC) and NOx emissions for pulverized coal when air staging combustion is applied. A two-staged drop tube furnace capable of applying air staging combustion was designed and installed. The combustion of sub-bituminous (Tanito) has been investigated. UBC and the NOx concentration were measured under various temperatures and stoichiometric ratios in unstaged and staged combustion. As a result, UBC decreased and the NOx concentration increased with an increase in stoichiometric ratio and temperature. In particular, the NOx reduction mechanism was activated when the temperature in the fuel rich zone increased. Both UBC and the NOx concentration decreased as the temperature increased in the fuel rich zone. A high NOx reduction effect was obtained, compared to the UBC increase, when the air staging technique was applied.

A Numerical Study on the Propane Combustion Characteristics in a Catalytic Combustor (프로판의 촉매연소 특성에 관한 수치적 연구)

  • Lee, Youn-Hwa;Kim, Chong-Min;Kim, Man-Young;Yu, Myoung-Jong
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • pp.247-250
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    • 2009
  • The catalytic combustor has the advantage of stable combustion under very lean conditions with low emissions of $NO_x$, CO and unburned hydrocarbon(UHC). Notwithstanding these advantages, the commercial application of the catalytic combustion has been delayed due to the complicated reaction process. For the stable operation of catalytic combustor, study on the combustion characteristics of the catalytic combustor is needed. So, in this study, numerical study on the propane combustion characteristics of the catalytic combustor with Pd-based catalyst is performed.

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Combustion and Emission Characteristics of Utility Boiler burning Anthracite-Bituminous Coal Blends (발전용 보일러에서의 유, 무연탄 혼소시 연소 및 환경특성)

  • Park, Ho-Young;Kim, Young-Joo;Park, Hyun-Joo;Kim, Sung-Chul
    • Journal of Energy Engineering
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    • v.17 no.3
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    • pp.153-160
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    • 2008
  • The combustion behaviors of the blends of Korean anthracite, bituminous coal and their blends were studied with a thermogravimetric analyzer. Concerning the burning profiles of the anthracite-bituminous coal blends in TGA, it has been observed the independent burning of two coals without any interaction between two coals. With the blends of 50% anthracite with 50% bituminous coal in weight basis, the combustion tests in a utility boiler have been carried out for the analysis of the combustion and operational characteristics by increasing the power output from 134 MW to 197 MW. The stable combustion has been observed in a boiler. With the increase of power output, the exhaust gas temperature was exceeded the design value of $430^{\circ}C$, so the combustion air was taken from atmosphere instead of the boiler penthouse.

Fundamental researches on combustion and applications (연소공학의 기초연구와 그 응용)

  • 신현동
    • Journal of the korean Society of Automotive Engineers
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    • v.11 no.4
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    • pp.13-18
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    • 1989
  • 연소 효율, 배기 특성을 제어하기 위하여 연소 반응대의 상세한 구조를 이해해야 하며 이를 토대로 열역학적 모델을 만들 필요가 있다. 본 고에서는 이미 여러 연구자들에 의하여 제안된 예혼합 화염의 반응대 구조에 대한 열적 모델과 확산모델을 소개하고 각각에 대한 응용과 가능성에 대하여 저자의 의견을 제시하였다.

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Catalytic Combustion of Soot Particulate over Perovskite-Type Oxides (폐롭스카이트형 촉매에서 입자상물질의 촉매연소반응)

  • Yang, Jin-Sup;Hong, Seong-Soo;Jung, Duck-Young;Oh, Kwang-Jung;Cho, Kyung-Mok;Ryu, Bong-Ki;Park, Dae-Won
    • Applied Chemistry for Engineering
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    • v.9 no.6
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    • pp.803-810
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    • 1998
  • We have studied the catalytic combustion of soot particulate over perovskite-type oxides prepared by malic acid method. The catalysts were modified to enhance the activity by substitution of metal into A or B site of perovskite oxide. In addition, the reaction conditions, such as temperature, $O_2$ concentration, space velocity have been studied. The effect of $SO_2$ pretreatment and water introduced into reactants were also examined. In the $LaCoO_3$ catalyst, the partial substitution of alkali metals into A site enhanced the catalytic activity in the combustion of soot particulate and the activity was shown in the order : Cs>K>Na; In the $La_{0.6}Cs_{0.4}CoO_3 $; catalyst, the substitution of Fe or Mn showed no effect on the ignition temperature. The ignition temperature decreased with increasing $O_2$ concentration and contact time. The introduction of water into reactants feed decreased the ignition temperature and the pretreatment of $SO_2$ showed no effect on the catalytic activity.

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A Kinetic Studies of Pyrolysis and Combustion of Sewage Sludge (하수 슬러지의 열분해 및 연소 Kinetics 연구)

  • Roh, Seon Ah
    • Resources Recycling
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    • v.23 no.6
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    • pp.47-53
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    • 2014
  • Effective treatment and energy conversion technologies are necessary due to the ban of the dumping of organic waste including the sewage sludge. In this study, the kinetics of pyrolysis and combustion were derived in a TGA and thermobalance reactor, which is essential for thermal conversion of sewage sludge to energy. Three steps are shown for the pyrolysis in TGA and the different pre-exponential factors and activation energies are derived depending on the temperature range. Three models of gassolid reaction were applied to the reaction kinetics analysis for the combustion of sewage sludge char and shrinking core model was an appropriated model. Apparent activation energy and pre-exponential factor were evaluated and the effect of oxygen partial pressure was examined.