• 에너지공학
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• 제6권1호
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• pp.34-40
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• 1997

자동차 촉매인 Pd/cordierite 촉매상에서 메탄의 연소시험을 통하여 천연가스 이용기술 활용가능성에 대해서 고찰하였다. 중고온 연소에서 알맞은 비표면적 18.7$m^2$/g 을 갖으며 안정한 구조를 확인하였다. 메탄 연소 반응시 활성화에너지는 19.2 kcal/mol로써 비교적 우수한 활성을 보여주었으며, 메탄 연소 반응의 승온과 온도를 내리면서 촉매의 비활성 특성을 보여주는 활성 히스테리시스 현상을 관찰하였다. Pd/cordierite 촉매상에서 반응온도 $700^{\circ}C$이하에서 공간속도와 공연비를 변화시키면서 메탄 연소특성을 수행하였다.

• 대한기계학회논문집B
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• 제23권10호
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• pp.1248-1253
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• 1999

This study is concerned about the combustion characteristics of methane-air and methane/hydrogen-air mainly the behavior of burning velocity including the effect of the ignition energy. The experiments were conducted in a spherical combustion bomb designed in this laboratory. The burning velocities were measured by the pressure-time history and the reaction rates were estimated theoretically. The experimental results showed that the burning velocity increased by 25 to 50 percent when hydrogen is added to methane by 20 percent.

• 한국연소학회지
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• 제13권3호
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• pp.9-16
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• 2008

In this study, a cylindrical constant volume combustion chamber is used to investigate the flow and combustion characteristics of methane-air homogeneous mixture under various initial charge pressure, excess air ratios and ignition times. The flame and burning speed, mean gas speed are calculated by numerical analysis to analyze the combustion characteristics. It is found that the mean gas velocity during combustion has the maximum value around 300 ms and then decreased gradually on the condition of 10000 ms, and that the combustion duration is shorten and flame speed and burning velocity have the highest value under the conditions of an excess air ratio 1.1, an initial charge pressure of 0.2 MPa and an ignition time of 300 ms in the present study. And, the initial pressure and burning speed are in inverse proportion, so that it is in agreement with Strehlow who presented that the initial pressure and burning speed are in inverse proportion when the burning speed is under 50cm/s.

• Bulletin of the Korean Chemical Society
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• 제31권1호
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• pp.120-124
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• 2010

Monometallic, bimetallic and trimetallic particles consisting of different weight compositions of Pt-Pd-Rh over pure alumina wash coats have been synthesized and their catalytic performance on methane conversion was studied from 150 to $600^{\circ}C$. Different catalyst formulations with variable Pt, Pd and Rh contents for bimetallic and trimetallic systems were tried and $Pt_{(1.5)}Rh_{(0.3)}/Al_2O_3$ and $Pt_{(1.0)}Pd_{(1.0)}Rh_{(0.3)}/Al_2O_3$ shows low $T_{50}$ and $T_{90}$ temperatures. Bimetallic and trimetallic particle synergism acts as three way catalysts and therefore, all the catalysts show 100% methane conversion. The effect of supports such as $ZrO_2$ and $TiO_2$ on methane combustion was investigated; from $T_{50}$ and $T_{90}$ results both $Al_2O_3$ and $ZrO_2$ are suitable supports for low temperature methane combustion.

• 한국연소학회지
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• 제17권2호
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• pp.1-8
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• 2012

Laminar flame speeds of Methane at elevated temperatures and pressures were investigated using constant volume spherical chamber. Pressure trace during combustion was measured in each test and this was used in calculating laminar flame speed of Methane. To have large amount of data, experimental apparatus was fabricated with fully automatically controlled feature. A calculating code which calculates laminar flame speeds at various temperatures and pressures with one experimental result was used to calculate laminar flame speeds. The experimental and calculating methods were verified using the calculated laminar flame speed result with PREMIX code.

• 청정기술
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• 제28권3호
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• pp.238-248
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• 2022

세계는 탄소 중립 사회로의 전환을 추진하고 있으며, 탄화수소계 연료를 수소로 대체함으로써 탄소 중립에 대한 기여를 기대할 수 있다. 하지만 수소 연소에 따른 질소산화물을 제어하기 위한 기술이 필요하며, 무화염 연소 기술이 하나의 대안이 될 수 있다. 본 연구는 수소 함량 및 배가스 재순환율에 따른 메탄-수소 연료의 연소 및 반응 특성을 분석하기 위해 Chemkin 기반의 1차원 대향류 확산화염 모델을 이용하여 해석을 수행하였다. 메탄 연소시 재순환율이 2에서 3으로 증가할 때 열방출의 흡열 구간이 없고 최대 열방출률 영역이 하나로 병합되는 무화염 연소가 달성되었다. 재순환율 3의 수소 전소 시 열방출 측면에서 무화염 연소가 달성되었으나, 화염 구조의 측면에서는 무화염 연소 달성 여부의 판단이 어렵다. 하지만 NO 생성량은 메탄 무화염 연소와 비교하여 유사한 수준으로 예측되었기에 수소 무화염 연소를 규정하기 위해서는 화염 구조, 열방출, NOx 생성에 대한 복합적인 고려가 필요하다.

• 한국연소학회지
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• 제8권1호
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• pp.17-24
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• 2003

The conventional regenerative system has a high thermal efficiency as well as energy saving using the high preheated combustion air. in spite of these advantages, it can not avoid high nitric oxide emissions. Recently, flameless combustion has received much attention to solve these problems. In this research, numerical analysis is performed for flow-combustion phenomena in the self regenerative burner. In this analysis we used Fluent 6.0 code. the that is developed for commercial use, Methane gas is used as a fuel and two-step reaction model for methane and Zeldovich mechanism for NO generation are used. the velocity of the preheated combustion air is used as a parameter and we analyze the characteristics of flow-field, temperature distributions and NO emissions. Due to the increased recirculation rate, the maximum temperature of flame is significantly increased and NOx emissions is reduced.

• 대한기계학회논문집B
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• 제33권5호
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• pp.343-348
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• 2009

The present study has experimentally investigated the effects of $CO_2$ diluted oxygen on the structure of swirl-stabilized flame in a lab-scale combustor. The methane fuel and oxidant mixture gas ($CO_2$ and $O_2$) were mixed in a pre-mixer and introduced to the combustor through different degrees of swirl vanes. The flame characteristics were examined for various amount of carbon dioxide addition to the methane fuel and various swirl strengths. The effects of carbon dioxide addition and swirl intensity on the combustion characteristics of pre-mixed methane flames were examined using chemiluminescence techniques to provide information about flow field. The results show that the hot combustion zone increases at the upstream reaction zone because of an increase in the recirculation flow for an increase in swirl intensity. The hot combustion zone is also increased at the downstream zone by recirculation flow because of an increase in swirl intensity which results in higher centrifugal force. The OH and CH radical intensities of reaction zone decrease with carbon dioxide addition because the carbon dioxide plays a role of diluted gas in the reaction zone.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2005년도 추계학술대회 논문집
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• pp.1190-1195
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• 2005

Biomass burning is a source of greenhouse gases, carbon dioxide, methane, and nitrous oxide. Under the ideal conditions of complete combustion, the burning of biomass produces carbon dioxide and water vapor. Since complete combustion is not achieved under any conditions of biomass burning, other carbon species, including carbon monoxide, methane, non-methane hydrocarbons and particulate carbon are produced. In this study, we analyze the combustion characteristics of rice-husk, such as heat release rate, smoke production rate, the percentage variation of CO and $CO_2$, oxygen consumption rate, and mass loss under different heat fluxes (20, 50 and 70kW). As a result, at 20kW incomplete combustion is occurred so that the percentage of CO is high in initial burning and total smoke release is higher than the others. At 50kW and 70kW, the combustion behaviors is very similar except the variation of CO percentage.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2015년도 제51회 KOSCO SYMPOSIUM 초록집
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• pp.83-86
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• 2015

The Laminar lifted methane jet flames diluted with helium and nitrogen in co-flow air have been investigated experimentally. The chemiluminescence intensities of $OH^{\ast}$ and $CH_2O^{\ast}$ radicals and the radius of curvature for tri-brachial flame were measured using an intensified charge coupled device (ICCD) camera, monochromator and digital video camera. The product of $OH^{\ast}$ and $CH_2O^{\ast}$ is used as a excellent proxy of heat release rate. These methane jet flames could be lifted in buoyancy and jet dominated regimes despite the Schmidt number less than unity. Lifted flames were stabilized due to buoyancy induced convection in buoyancy-dominated regime. It was confirmed that increased $OH^{\ast}$ and $CH_2O^{\ast}$ concentration caused an increase of edge flame speed via enhanced chemical reaction in buoyancy dominated regime. In jet momentum dominated regime lifted flames were observed even for nozzle exit velocities much higher than stoichiometric laminar flame speed. An increase in radius of curvature in addition to the increased $OH^{\ast}$ and $CH_2O^{\ast}$ concentration stabilizes such lifted flames.