• Title/Summary/Keyword: 촉매 연소기

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Steady & Pulse Mode Fire Tests of Hydrazine Thrusters (단일 하이드라진 추력기 연소시험 성능평가)

  • 이성택;이상희;최영종;류정호
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 1998.04a
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    • pp.31-31
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    • 1998
  • 위성체의 보조추진시스템은 임구궤도까지의 궤도진입 및 임무궤도상에서의 속도 또는 자세제어에 필요한 임펄스를 제공한다. 단일하이드라진 추력기는 하이드라진(H$_2$H$_4$)과 자발적 촉매(Shell 405)의 발열 및 흡열 열분해 반응에 의해 발생하는 질소($N_2$), 수소(H$_2$), 암모니아(NH$_3$), 혼합가스를 노즐을 통해 방출하므로써 요구되는 impulse를 얻는다. 단일하이드라진 추력기 설계는 주입기, 촉매대, 노즐과 기타 설계 형태에 따른 다지관, 링, 스크린, 지지판 등의 부수적인 부품으로 구성된다. 추력기 제작 과정은 크게 piece-parts 기계가공, HEA(Head End Assembly)와 TCA(Thrust Chamber Assembly)로 구성되고 각 세부공정마다 전수시험 및 검사를 가진다. 연소시험설비는 최소 모사진 공 수준이 고도 100,000 ft(8.4 torr)를 만족시킬 수 있는 진공설비, 시험제어부, 성능변수 측정 및 처리부, 추진제 가압 공급부, 기타 환경 안전 및 부대 설비로 구성된다. 추력기 연소성능시험 절차는 추진제 충전 및 오염 여부 표본 검사, 가압 및 공급 라인 이상여부 확인, 추력기 장착, 추진제 가압 및 공급, 시험장치 보정, 진공 모사 및 연소성능시험, data 처리 등으로 구성된다.

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A Study on the Modeling of Pt-Catalyzed Reaction and the Characteristics of Mass Transfer in a Micro-Scale Combustor (마이크로 스케일 연소기의 백금 촉매 반응 모델링과 물질 전달 특성에 대한 연구)

  • Lee, Gwang-Goo;Suzuki, Yuji
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.32 no.11
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    • pp.870-877
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    • 2008
  • Numerical analysis is applied to model Pt-catalyzed reaction in a micro-scale combustor fueled by butane. The reaction constants of catalytic oxidation are determined from plug flow model with the experimental data. Orders of magnitude between the chemical reaction rate and the mass transfer rate are carefully compared to reveal which mechanism plays a dominant role in the total fuel conversion rate. For various conditions of fuel flow rate and surface temperature, the profiles of Sherwood number are investigated to study the characteristics of the mass transport phenomena in the micro-tube combustor.

Fabrication and Performance Test of MEMS Catalytic Combustors Using Photosensitive Glass Wafer (감광유리를 이용한 MEMS 촉매 연소기의 제작 및 성능 평가)

  • Jin, Jung-Kun;Kwon, Se-Jin
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.33 no.3
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    • pp.237-242
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    • 2009
  • MEMS catalytic combustors were fabricated to use in micro-power sources as a heat source. The combustor was fabricated by photolithography and anisotropic wet etching of photosensitive glass wafers. Two different catalyst loading methods were used to complete the fabrication of the combustors. For thin film type, the $Al_2O_3$ was washcoated on the surface of the combustion chamber as a catalyst support, and for packed-bed type, ceramic foam was inserted after Pt was coated. The volume of the combustors was 1.8 $cm^3$ and 16W of heat was generated using the fabricated combustors with hydrogen. The energy density of combustor was about 8.9 W/$cm^3$.

The study of combustion gas characteristic by incinerator operation condition. (소각로 운영조건에 따른 연소배가스 특성 연구)

  • Lee, Keon-Joo
    • Journal of the Korea Organic Resources Recycling Association
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    • v.18 no.1
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    • pp.66-72
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    • 2010
  • This study was done to analyze the condition of combustion exhaust gas that is produced according to incinerator operating condition in A area Kyonggido. The boiler exhaust gas temperature, the oxygen concentration of boiler, the outgassing temperature of Semi Drying Sorber(SDS), the temperature of catalytic reactor, the concentration of NOx, SOx, CO, Hcl and Dust were investigated by change the temperature of incinerator. The concentration of SOx, CO, HCL and DUST were below 5 ppm as increase the temperature of incinerator however the concentration of NOx was increased from 40 ppm to 70 ppm as increase the temperature of incinerator. The boiler exhaust gas temperature and the temperature of catalytic reactor were not changed however the oxygen concentration of boiler was decreased gradually as increase the temperature of incinerator.

Characteristics of the Pressure Instability in a Hydrazine Thruster with Various Length-to-Diameter Ratio of Catalyst-bed (하이드라진 추력기의 촉매대 길이직경비에 따른 압력 불안정 특성)

  • Jung, Hun;Kim, Jong Hyun;Kim, Jeong Soo
    • Journal of the Korean Society of Propulsion Engineers
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    • v.18 no.6
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    • pp.19-26
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    • 2014
  • A ground hot-firing test (HFT) was carried out to make a close examination into the pressure instability for the 70 N-class hydrazine thruster under development. Monopropellant grade hydrazine was adopted as a propellant for the HFT, and catalyst-bed was filled with $Ir/Al_2O_3$ catalyst. In order to investigate the effects of thrust-chamber diameter on combustion stability, evaluation tests for the development models were performed on three kinds of lower thrust chambers having the length-to-diameter ratio (L/D) of 1.03, 1.13, and 1.26. As results, it was found that low frequency instability (~ 50 Hz) was inherent in the models, and in addition, increase of the L/D and decrease of the operating pressure led to an amplification of pressure oscillation in the test condition specified.

Control of NOx Emission in a Copper-Alumina Catalytic Filter Reactor (Copper-Alumina 촉매필터 반응기에서의 NOx 제어)

  • 류동길;이상권
    • Proceedings of the Korea Air Pollution Research Association Conference
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    • 2002.11a
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    • pp.263-264
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    • 2002
  • 연소시설에서 배연가스중의 NOx 배출을 저감하기 위하여 선택적 촉매 환원법(SCR)과 선택적 무촉매 환원법(SNCR)이 널리 이용되고 있다. 이러한 촉매처리는 Pt와 같은 귀금속이 포함된 촉매 하에서 암모니아를 환원제로 사용하였으나, R와 같은 귀금속의 경우 배연가스내에 함유된 중금속이나 비소(Arsenic), SOx, 비산재(fly ash)등에 의해 쉽게 비활성화(deactivation)되는 단점이 있다(Sumitra R et al., 1995). (중략)

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Numerical Investigation of the Flow and Mixing Characteristics with the Static Mixer in a Catalytic Combustor for the MCFC Power Plant System (MCFC 발전시스템 적용 촉매연소기의 혼합 특성 향상을 위한 Static Mixer의 유동에 관한 수치적 연구)

  • Kim, Chong-Min;Park, Nam-Seob;Kim, Man-Young
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.33 no.3
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    • pp.149-155
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    • 2009
  • In this work a numerical study to find the characteristics of the internal flow and mixing process has been conducted in a static mixer used in the system of catalytic combustor of the fuel cell power plant. After introducing the model description and final governing equations the present numerical approach is applied to the analysis of static mixer, which may have one or more helical elements inside the circular tube by changing such various parameters as incoming mass flow rates and the number of helical elements. The results show that although the static mixer is efficient in mixing fuel and air, more optimization processes are required to achieve the appropriate mixing characteristics in front of the honeycomb type catalytic combustor used in the MCFC power plant

Emission After-Treatment System of Model Gas Turbine Using Catalyst (촉매를 이용한 모형가스터빈 연소기의 배기후처리 시스템)

  • Lee, Y.H.;Lee, J.S.;Bae, D.S.;Lee, D.H.
    • Journal of Power System Engineering
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    • v.7 no.3
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    • pp.12-17
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    • 2003
  • The purpose of this study is to observe the purification characteristics of NOx, CO and HC in various catalysts and excess air ratio conditions. For this purpose, we installed various catalysts on the back stream of the coaxial diffusion burner with swirler. As the result, in the case of NOx, Pt-Rh catalyst shows very high value that is more than 90%-conversion efficiency without the relation with the excess air ratio. After excess air ratio of ${\alpha}=1.14$, it shows that the conversion efficiencies were more than 80% in the every Pt catalyst in the view of conversion of every exhaust with changing of the excess air ratio.

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An Investigation on Combustion Characteristics of Hydrogen-Air Premixture in a Sub-millimeter Scale Catalytic Combustor using Infrared Thermography (적외선 열화성 온도 측정법을 이용하여 살펴본 서브밀리미터 스케일 촉매 연소기에서의 수소-공기 예혼합 가스의 촉매 연소 특성)

  • Choi, Won-Young;Kwon, Se-Jin
    • Journal of the Korean Society of Combustion
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    • v.10 no.3
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    • pp.17-24
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    • 2005
  • A sub-millimeter scale catalytic combustor with a simple plate-shaped combustion chamber was fabricated. A porous ceramics support coated with platinum catalyst was placed in the chamber. The combustor has a gallium arsenide window on the top that is transparent to infrared ray. The temperature distribution in the combustion chamber was measured using infrared thermal imager while hydrogen-air premixture is steadily supplied to the combustor. The area where the catalytic reaction took place broaden for higher flow rate and lower equivalence ratio made activated area in the combustion chamber broaden. The amount of coated platinum catalyst did not affect the reaction. Stop of reaction, which is similar to flame quenching of conventional combustion, was investigated. Large content of heat generation and broad activated area are essential criteria to prevent stop of reaction that has a bad effect on the combustor performance.

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Effect of Flow Uniformity Device on the Catalytic Combustor for 5 kW High Temperature Fuel Cell System (5 kW급 고온형 연료전지 촉매 연소기 유동 균일화 장치가 연소 특성에 미치는 영향)

  • Lee, Sang-Min;Woo, Hyun-Tak;Ahn, Kook-Young
    • Transactions of the Korean hydrogen and new energy society
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    • v.22 no.6
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    • pp.878-883
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    • 2011
  • Effect of flow uniformity on the reaction characteristics of a catalytic combustor for high temperature fuel cell system has been experimentally investigated in the present study. One of the most important factor in designing catalytic combustion is to avoid hot spot in catalysts. In this regard, it is very important to secure flow uniformity of combustor inlet. A couple of perforated plates were applied at the front of catalyst region as flow uniformity device with minimal pressure drop. Results show that the velocity and temperature profile became more uniform when applying the flow uniformity device. CO and $CH_4$ emissions at the combustor exit were decreased and the average exit temperature was slightly increased with the flow uniformity device.