• Title/Summary/Keyword: Reforming chamber

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Computational Fluid Dynamics Analysis of 25kW Plate Type Methane-steam Reformer (25kW급 평판형 메탄-수증기 개질기 열유동 전산해석)

  • Shin, Dong-Hoon;Seo, Hye-Gyung;Lim, Hee-Chun;Lee, Sang-Duk
    • 한국신재생에너지학회:학술대회논문집
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    • 2006.06a
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    • pp.103-106
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    • 2006
  • The Plate reformer consisting of combustion chamber and reforming chamber for 25 kW MCFC stack has been operated and computational fluid dynamics was applied to estimate reactions and thermal fluid behavior in the reformer. The methane air 2-stage reaction was assumed in the combustion chamber, and three step steam reforming reactions were included in the calculation. Flow uniformity, reaction rate and species distribution, and temperature distribution were analyzed. In particular, temperature distribution was compared with the measurements to show good agreement in the combustion chamber, however, inappropriate agreement in the reformer chamber

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Computational Fluid Dynamics Analysis of Plate Type Reformer for MCFC (용융탄산염 연료전지용 평판형 개질기 열유동 전산유체역학 해석)

  • Shin, Dong-Hoon;Seo, Hye-Gyung;Lim, Hee-Chun;Lee, Sang-Duk
    • Transactions of the Korean hydrogen and new energy society
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    • v.17 no.4
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    • pp.403-408
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    • 2006
  • The plate reformer consisting of combustion chamber and reforming chamber for 25 kW MCFC stack has been operated and computational fluid dynamics was applied to estimate reactions and thermal fluid behavior in the reformer. The methane air 2-stage reaction was assumed in the combustion chamber, and three step steam reforming reactions were included in the calculation. Flow uniformity, reaction rate and species distribution, and temperature distribution were analyzed. In particular, temperature distribution was compared with the measurements to show good agreement in the combustion chamber, however, inappropriate agreement in the reformer chamber.

Kinetic Study on the Mixing Region of a Hydrocarbon Reformer (개질기 혼합영역에서 탄화수소 연료의 반응 특성에 대한 연구)

  • Kim, Sun-Young;Bae, Joong-Myeon
    • Transactions of the Korean hydrogen and new energy society
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    • v.22 no.3
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    • pp.357-362
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    • 2011
  • Complete mixture preparation of reactants prior to catalytic reforming is an enormously important step for successful operation of a fuel reformer. Incomplete mixing between fuel and reforming agents such as air and steam can cause temperature overshoot and deposit formation which can lead the failure of operation. For that purpose it is required to apply computational models describing coupled kinetics and transport phenomena in the mixing region, which are computationally expensive. Therefore, it is advantageous to analyze the gas-phase reaction kinetics prior to application of the coupled model. This study suggests one of the important design constraints, the required residence time in the mixing chamber to avoid substantial gas-phase reactions which can lead serious deposit formation on the downstream catalyst. The reactivity of various gaseous and liquid fuels were compared, then liquid fuels are far more reactive than gaseous fuels. n-Octane was used as a surrogate among the various hydrocarbons, which is one of the traditional liquid fuel surrogates. The conversion was slighted effected by reactants composition described by O/C and S/C. Finally, threshold residence times in the mixing region of a hydrocarbon reformer were studied and the mixing chamber is required to be designed to make complete mixture of reactants by tens of milliseconds at the temperature lower than $400^{\circ}C$.

Convergent Study on the Hydro-Gas Reforming Cyclo-Incinerator (물 가스 개질 고속선회 소각로에 관한 융합연구)

  • Han, Doo-Hee
    • Journal of the Korea Convergence Society
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    • v.11 no.10
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    • pp.231-236
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    • 2020
  • A water reforming reaction high-speed turning incinerator test facility was prepared. The reforming reaction chamber and the combustion chamber were directly connected. The incinerator and dust collecting device were integrated and made into a double bulkhead type air cooling structure. The blower is built into the dust collector to improve spatial efficiency. An axial flow type multi-stage dust collector was applied by collecting dust by using a plurality of dust collecting bins attached to the side of the dust collecting part. As a result of measuring dioxin among the exhausted gases, results below the standard value were obtained. As a result of measuring exhaust gas and heavy metals, results were obtained below the environmental standard.

The Performance & Operation Analysis of a Plate Type Reformet for 2 kW Class MCFC Stack (2 kW급 MCFC용 평편형 개질기 운전결과)

  • Seo, Hal-Kung;Ahn, Kyo-Sang;Lim, Hee-Chun;Lee, Sang-Deuk
    • Transactions of the Korean hydrogen and new energy society
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    • v.13 no.2
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    • pp.159-167
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    • 2002
  • The operation results of the 2kW class plate type reformer, which has several advantages compared with the tubular burner type reformer, are analyzed. This plate type reformer is composed of six combustion chambers and five reforming chambers by turns. The methane conversion rate at 1.6 absolute pressure is about 84%, which is reasonably similar to theoretical value, 85.3%. Though the abrupt interruption was made just by the carbon deposition during heating the fuel line to combustion chambers around 200 hours operation, the overall steady state operation is more than 450 hours. These operation results show the verification of long run performance and the possibility of direct connection between plate reformer and fuel cell stack.

Effect of Tip Size and Aspect Ratio on Reforming Performance in a Methane Reformer for Polymer Electrolyte Membrane Fuel Cell (PEMFC) (고분자 전해질 막 연료전지를 위한 메탄 개질기에서 형상 변화가 개질 성능에 미치는 영향에 대한 연구)

  • Seo, Dong-Kyun;Noh, In-Kyu;Hwang, Jung-Ho;Choi, Jong-Kyun;Shin, Dong-Hoon;Kim, Hyung-Sik
    • Transactions of the Korean hydrogen and new energy society
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    • v.21 no.5
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    • pp.364-374
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    • 2010
  • Design of a reformer consisting of combustion chamber and reforming chamber was investigated for a 1 kW and a 5 kW polymer electrolyte membrane fuel cell (PEMFC), respectively, using the computational fluid dynamics (CFD). First, the 1kW reformer was considered to obtain the reliability of the numerical study. It was modeled, calculated and compared with experimental data. Second, the 5kW reformer was considered for a geometric study. Three tip sizes (35, 40, and 45 mm) and five aspect ratios was selected. It was found that the optimum was at tip sizes of 40 and 45 mm, at aspect ratios of -10% and -20% of the standard length.

Performance of a Molten Carbonate Fuel Cell With Direct Internal Reforming of Methanol (메탄올 내부개질형 용융탄산염 연료전지의 성능)

  • Ha, Myeong Ju;Yoon, Sung Pil;Han, Jonghee;Lim, Tae-Hoon;Kim, Woo Sik;Nam, Suk Woo
    • Clean Technology
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    • v.26 no.4
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    • pp.329-335
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    • 2020
  • Methanol synthesized from renewable hydrogen and captured CO2 has recently attracted great interest as a sustainable energy carrier for large-scale renewable energy storage. In this study, molten carbonate fuel cell's performance was investigated with the direct conversion of methanol into syngas inside the anode chamber of the cell. The internal reforming of methanol may significantly improve system efficiency since the heat generated from the electrochemical reaction can be used directly for the endothermic reforming reaction. The porous Ni-10 wt%Cr anode was sufficient for the methanol steam reforming reaction under the fuel cell operating condition. The direct supply of methanol into the anode chamber resulted in somewhat lower cell performance, especially at high current density. Recycling of the product gas into the anode gas inlet significantly improved the cell performance. The analysis based on material balance revealed that, with increasing current density and gas recycling ratio, the methanol steam reforming reaction rate likewise increased. A methanol conversion more significant than 90% was achieved with gas recycling. The results showed the feasibility of electricity and syngas co-production using the molten carbonate fuel cell. Further research is needed to optimize the fuel cell operating conditions for simultaneous production of electricity and syngas, considering both material and energy balances in the fuel cell.

An Experimental Study on Flammability Limits and Combustion Characteristics of Synthetic Gas in a Constant Combustion Chamber (정적연소기를 이용한 합성가스의 가연한계 및 연소특성에 관한 실험적 연구)

  • Cho, Yong-Seok;Lee, Seang-Wock;Won, Sang-Yeon;Park, Young-Joon;Kim, Duk-Sang
    • Transactions of the Korean Society of Automotive Engineers
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    • v.16 no.1
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    • pp.14-21
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    • 2008
  • Synthetic gas is defined as reformed gas from hydrocarbon-based fuel and the major chemical species of the synthetic gas are $H_2$, CO and $N_2$. Among them, hydrogen from synthetic gas is very useful species in chemical process such as combustion. It is a main reason that many studies have been performed to develop an effective reforming device. Furthermore, other technologies have been studied for synthetic gas application, such as the ESGI(Exhaust Synthetic Gas Injection) technology. ESGI injects and burns synthetic gas in the exhaust pipe so that heat from hydrogen combustion helps fast warmup of the close-coupled catalyst and reduction of harmful emissions. However, it is very hard to understand combustion characteristic of hydrogen under low oxygen environment and complicated variation in chemical species in exhaust gas. This study focuses on the characteristics of hydrogen combustion under ESGI operating conditions using a CVC(Constant Volume Chamber). Measurements of pressure variation and flame speed have been performed for various oxygen and hydrogen concentrations. Results have been analyzed to understand ignition and combustion characteristics of hydrogen under lower oxygen conditions. The CVC experiments showed that under lower oxygen concentration, amount of active chemicals in the combustion chamber was a crucial factor to influence hydrogen combustion as well as hydrogen/oxygen ratio. It is also found that increase in volume fraction of oxygen is effective for the fast and stable burning of hydrogen by virtue of increase in flame speed.

The Efficiency Prediction for Plate Type Steam Reformer with Shape Change of Combustion Chamber (평판형 STR의 연소공간 형상변화에 따른 성능 예측)

  • Kim, Hun-Ju;Lee, Ji-Hong;Lee, Myeong-Yong;Lee, Sang-Seok;Lee, Do-Hyung
    • Transactions of the Korean hydrogen and new energy society
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    • v.21 no.4
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    • pp.286-294
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    • 2010
  • According to the propagation of fuel cell system, the importance of that system efficiency is being magnified. Thus, the efficiency improvement of reformer which is the important part of fuel cell system will be required. In structural aspect, the reformer is classified into cylindrical and plate type. Plate type reformer features better maintenance and space efficiency compared with cylindrical type. In this study, we changed the shape of combustion chamber to improve the reforming efficiency. And then we performed the CFD simulation to predict the spacial distribution of temperature. Analysis cased contains with baffles, fins, baffles and fins, and without those. In case of only with-baffle, temperature distributions were uneven because the high temperature stream was concentrated near the baffle end. In case of with-fin, the temperature distributions were relatively even than other cases.

CaO Manufacture for $CO_2$ Adsorption at a High Temperature (고온에서의 이산화탄소 흡착을 위한 흡착제 CaO 제조)

  • Lee Tae-Jong;Kim Gil-Soo;Baek Il-Hyun;Kim Bu-Ung
    • Journal of the Korean Institute of Gas
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    • v.5 no.4 s.16
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    • pp.27-32
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    • 2001
  • It is desired that carbon dioxide causing a greenhouse effect be removed at a high temperature and high pressure in a steam reforming reaction. In this research, a pellet form of adsorbent CaO is employed to capture $CO_2$. The adsorbent was manufactured using a high pressure molding on powdered $CaCO_3$ followed by calcination. Then its properties were analyzed and the adsorption experiments were carried out in a batch adsorption chamber. The pore area was found to be dependent on a molding pressure and the pore distribution showed two peaks. It is examined that $CO_2$ binds to CaO by means of chemisorption and its maximum conversion is nearly $80\%$ at $700^{\circ}C$.

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