• Title, Summary, Keyword: Reformer

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A CFD Study on Unsteady and Steady State of the Hydrogen Leakage for Residential Fuel Cell System (가정용 연료전지 시스템 내부 수소 누출의 비정상 및 정상 상태에 관한 전산 해석)

  • Chung, Tae-Yong;Ahn, Jae-Uk;Nam, Jin-Hyun;Shin, Dong-Hoon;Kim, Young-Gyu
    • Journal of the Korean Institute of Gas
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    • v.11 no.4
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    • pp.41-46
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    • 2007
  • The residential fuel cell system was modeled as a box-shaped chamber with vent openings, filled with various components such as reformer, desulfurizer, fuel cell stack and humidifier. When the vent openings are 1% of the total surface and hydrogen leakage 1%, hydrogen concentration is around 0.1% higher than the other regions from leak points in the chamber at 30 seconds and hydrogen concentration is increased from 0.3% to 0.7% in the upper region of the system after 200 seconds. When the vent openings are 1% of the total surface and hydrogen leakage 1%, 3%, 5%, the steady state result of CFD, 5% of hydrogen leakage is reached the lowest ignition limit in the system. When the vent openings are 2% of the total surface and hydrogen leakage 1%, hydrogen concentration is increased in the bottom of the system for 60 seconds. After 250 seconds, hydrogen concentration is reached the steady state in the system. As the vent opening of the total surface increased from 1% to 2%, averaged hydrogen mole fraction is under 1% in the system, however, upper regions of the system from the hydrogen leakage points are shown over 1% of hydrogen mole fraction.

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Effect of the Molar H2O/ and the Molar O2/C Ratio on Long-Term Performance of Diesel Autothermal Reformer for Solid Oxide Fuel Cell (고체산화물 연료전지용 디젤 자열개질기의 장기성능에 미치는 H2O/C와 O2/C 몰 비의 영향)

  • Yoon, Sang-Ho;Kang, In-Yong;Bae, Gyu-Jong;Bae, Joong-Myeon
    • Journal of the Korean Electrochemical Society
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    • v.10 no.2
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    • pp.110-115
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    • 2007
  • Solid oxide fuel cell(SOFC) has high fuel flexibility due to its high operating temperatures. Hydrocarbonaceous fuels such as diesel has several advantages such as high energy density and established infrastructure for fuel cell applications. However diesel reforming has technical problems like coke formation in a reactor, which results in catastrophic failure of whole system. Performance degradation of diesel autothermal reforming (ATR) leads to increase of undesirable hydrocarbons at reformed gases and subsequently degrades SOFC performance. In this study, we investigate the degradation of SOFC performance(OCV, open circuit voltage) under hydrocarbon(n-Butane) feeds and characteristics of diesel performing under various ratios of reactants($H_2O/C,\;O_2/C$ molar ratios) for improvement of SOFC performance. Especially we achieved relatively high performance of diesel ATR under $H_2O/C=0.8,\;O_2/C=3$ condition.

A Comparative Study of Various Fuel for Newly Optimized Onboard Fuel Processor System under the Simple Heat Exchanger Network (연료전지차량용 연료개질기에 대한 최적연료비교연구)

  • Jung, Ikhwan;Park, Chansaem;Park, Seongho;Na, Jonggeol;Han, Chonghun
    • Korean Chemical Engineering Research
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    • v.52 no.6
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    • pp.720-726
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    • 2014
  • PEM fuel cell vehicles have been getting much attraction due to a sort of highly clean and effective transportation. The onboard fuel processor, however, is inevitably required to supply the hydrogen by conversion from some fuels since there are not enough available hydrogen stations nearby. A lot of studies have been focused on analyses of ATR reactor under the assumption of thermo-neutral condition and those of the optimized process for the minimization of energy consumption using thermal efficiency as an objective function, which doesn't guarantee the maximum hydrogen production. In this study, the analysis of optimization for 100 kW PEMFC onboard fuel processor was conducted targeting various fuels such as gasoline, LPG, diesel using newly defined hydrogen efficiency and keeping simply synthesized heat exchanger network regardless of external utilities leading to compactness and integration. Optimal result of gasoline case shows 9.43% reduction compared to previous study, which shows the newly defined objective function leads to better performance than thermal efficiency in terms of hydrogen production. The sensitivity analysis was also done for hydrogen efficiency, heat recovery of each heat exchanger, and the cost of each fuel. Finally, LPG was estimated as the most economical fuel in Korean market.

An Experimental Study on the Combustion Characteristics of a Catalytic Combustor for an MCFC Power Generation System (MCFC 발전시스템용 촉매연소기의 연소 특성에 관한 실험적 연구)

  • Hong, Dong-Jin;Ahn, Kook-Young;Kim, Man-Young
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.36 no.4
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    • pp.405-412
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    • 2012
  • In the MCFC power generation system, the combustor supplies a high temperature mixture of gases to the cathode and heat to the reformer by using the off-gas from the anode; the off-gas includes high concentrations of $H_2O$ and $CO_2$. Since a combustor needs to be operated in a very lean condition and avoid local heating, a catalytic combustor is usually adopted. Catalytic combustion is also generally accepted as one of the environmentally preferred alternatives for generation of heat and power from fossil fuels because of its complete combustion and low emissions of pollutants such as CO, UHC, and $NO_x$. In this study, experiments were conducted on catalytic combustion behavior in the presence of Pd-based catalysts for the BOP (Balance Of Plant) of 5 kW MCFC (Molten Carbonate Fuel Cell) power generation systems. Extensive investigations were carried out on the catalyst performance with the gaseous $CH_4$ fuel by changing such various parameters as $H_2$ addition, inlet temperature, excess air ratio, space velocity, catalyst type, and start-up schedule of the pilot system adopted in the BOP.

Character of MongYong in Original ChunHyang Jun Films of Shin Sang-Ok directed in North and South Korea - Political Sociological Aspect of Characterization (신상옥 연출 남북한 『춘향전』 원작 영화 속 몽룡 '들' - 정치사회학적 관점에서 본 '캐릭터성격화')

  • Ahn, Soong-Beum
    • Cross-Cultural Studies
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    • v.42
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    • pp.343-369
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    • 2016
  • This is an attempt to analyze original films of ChunHyang Jun that Shin Sang-Ok filmed in North and South Korea, focusing on the character of MongYong. These films were made during political transition periods of North and South Korea. Sung ChunHyang was made during the second republic of South Korea, which was established after the collapse of Rhee SyngMan government; and Love, Love, My Love was made in North Korea during the period of power transfer from Kim Il-Sung to Kim Jong-Un. Considering these political changes, the character of MongYong seems to represent the figure of authority North and South Korean society of the time had in mind. First, MongYong in Sung ChunHyang has a strong image of a lover who repays ChunHyang's devotion and sacrifice with romantic affection. As an authoritative figure, he has the aspect of a democratic leader or mediator. On the other hand, MongYong's image in Love, Love, My Love is a heroic authority figure of the revolutionary class. He is a subversive reformer who shows love for the people and treats them favorably, gaining public desire. This research is expected to inspire more studies on the meanings of hit movies based on classic literature under synchronic terms.

A Criticism about Neo-Confucianism and progressive Thought of Fu-Shan(傅山) (부산(傅山)의 리학(理學)비판과 개혁사상)

  • Hwang, Byong Kee
    • (The)Study of the Eastern Classic
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    • no.37
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    • pp.411-439
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    • 2009
  • Fu-Shan(傅山, 1607~1684) was a progressive actualist between the late Ming(明) dynasty and the early Qing(淸) dynasty. He regards the intellectuals at that time as scarecrows leaned on the empty and exaggerative moral philosophy which the neo-confucian of Song(宋) dynasty established. He thinks that the neo-confucian discussion cause harmful side effects, disregarding the utility side and the variety of the actual world. His thought becomes known all in political thought and literature. He asserts that the neo-confucian ideas provides the logical frame which regulates the actual world and creates a kind of absolute moral ideology. Therefore he insists that the Saint in the true sense of the word consequently is the social reformer and revolutionist who exposes the irrational elements of society. He insists that literature also must be able to express vividness of the actual world. He thinks that genuine literature must have creative contents and find one's own free wild way. He asserts that old literary style from the mimicry is the act which goes against human natural. He thinks that the writing must be able to express the actual world.

Expansion and Transition of Tasan's Allegoric Poetry (다산(茶山) 우화시(寓話詩)의 확장(擴張)과 전이(轉移) -<오즉어행>과 <리노행>을 중심(中心)으로-)

  • Lee, Kyung-ah
    • Journal of Korean Classical Literature and Education
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    • no.15
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    • pp.329-353
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    • 2008
  • Tasan Jeong Yak-yong is great scholar, who makes a synthesis of Sil-hak[實學, Practical Science of Korea], reformer of society, and a poet in the Joseon Dynasty. He expressed contradiction and conflict of those days by intellectual language, and reperceived basic ideology of the Joseon society. Also he theorized dissatisfaction of the people about those days and its system as form of religion. We can divide Tasan's life into two times. The first part is his ages 16~39 in the period of Jeong-jo(1777~1800). The second part is in the period of Sun-jo(1801~1834). In this period, he was exiled into Gang-jin for 17 years. After banishment, he lived a quiet life for the rest of his life in his hometown. His allegoric poetry were written in this second period. The special feature of allegoric poetry is strong satire. An allegory would be that is 'king's ear', which the barber has sight, or the barber's voice, which has divulged king's secret among the bamboos. Otherwise it would be that is the sound 'king's ear is donkey's ear' in the bamboos. This sound is divulging of the true donkey's ear. It doesn't travel to audiences, but travels trough wind in the bamboos. The narration exists just as story that barber can't stand to keep silence about king's secret. There are exposure of true and critical motive as allegoric expression. Tasan's allegoric poetry stand on the basis of his love for the people. Also there reveals his thought deeply with an enormous amount of reading and self-communion. Moreover there are his warm mind with his sharp insight in which captures alive lives as allegoric materials. Most of allegoric poetry satirize actuality of those days to make an excuse for external distinguishing marks of animals and plants. However Tasan's poetry are different from them. After he grasped serious problems from his contemporary actuality, and then choosed allegoric media to express correctly. Because he grasped the special features of lives after minute observation, he could exposure controversial point of the actual. His sharp insight was not limited to allegoric media. He noticed his period and the current of his society sensitively. It made his allegoric poetry as important materials to make us to know the condition of the people in the Joseon Dynasty. Tasan's allegoric poetry is inherited by Baek Seok[白石, 1912~1995] as regular juvenile literature. Baek Seok's juvenile stories are the results of expansion and transition for Tasan's allegoric poetry. Allegoric poetry was the shout of barber to prosecute about social irregularities and contradiction, and the sound of the bamboos to travel moaning of the people in the past. Now allegoric poetry create new emotion to make us to speculate ourselves with our surrounding. This changes are caused by special feature of allegoric poetry as a form to reflect our general lives.

Recent Progress in Air-Conditioning and Refrigeration Research: A Review of Papers Published in the Korean Journal of Air-Conditioning and Refrigeration Engineering in 2011 (설비공학 분야의 최근 연구 동향: 2011년 학회지 논문에 대한 종합적 고찰)

  • Han, Hwa-Taik;Lee, Dae-Young;Kim, Seo-Young;Choi, Jong-Min;Paik, Yong-Kyoo;Kim, Su-Min
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.24 no.6
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    • pp.521-537
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    • 2012
  • This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2011. It is intended to understand the status of current research in the areas of heating, cooling, ventilation, sanitation, and indoor environments of buildings and plant facilities. Conclusions are as follows. (1) Research trends of thermal and fluid engineering have been surveyed as groups of fluid machinery and fluid flow, thermodynamic cycle, and new and renewable energy. Various topics were presented in the field of fluid machinery and fluid flow. Research issues mainly focused on the rankine cycle in the field of thermodynamic cycle. In the new and renewable energy area, researches were presented on geothermal energy, fuel cell, biogas, reformer, solar water heating system, and metane hydration. (2) Research works on heat transfer area have been reviewed in the categories of heat transfer characteristics, pool boiling and condensing heat transfer, nanofluids and industrial heat exchangers. Researches on heat transfer characteristics included heat transfer above liquid helium surface in a cryostat, methane hydrate formation, heat and mass transfer in a liquid desiccant dehumidifier, thermoelectric air-cooling system, heat transfer in multiple slot impinging jet, and heat transfer enhancement by protrusion-in-dimples. In the area of pool boiling and condensing heat transfer, researches on pool boiling of water in low-fin and turbo-B surfaces, pool boiling of R245a, convective boiling two-phase flow in trapezoidal microchannels, condensing of FC-72 on pin-finned surfaces, and natural circulation vertical evaporator were actively performed. In the area of nanofluids, thermal characteristics of heat pipes using water-based MWCNT nanofluids and the thermal conductivity and viscosity were measured. In the area of industrial heat exchangers, researches on fin-tube heat exchangers for waste gas heat recovery and Chevron type plate heat exchanger were implemented. (3) Refrigeration systems with alternative refrigerants such as $CO_2$, hydrocarbons, and mixed refrigerants were studied. Heating performance improvement of heat pump systems were tried applying supplementary components such as a refrigerant heater or a solar collector. The effects of frost growth were studied on the operation characteristic of refrigeration systems and the energy performance of various defrost methods were evaluated. The current situation of the domestic cold storage facilities was analyzed and the future demand was predicted. (4) In building mechanical system fields, a variety of studies were conducted to achieve effective consumption of heat and maximize efficiency of heat in buildings. Various researches were performed to maximize performance of mechanical devices and optimize the operation of HVAC systems. (5) In the fields of architectural environment and energy, diverse purposes of studies were conducted such as indoor environment, building energy, and renewable energy. In particular, renewable energy and building energy-related researches have mainly been studied as reflecting the global interests. In addition, various researches have been performed for reducing cooling load in a building using spot exhaust air, natural ventilation and energy efficiency systems.

Experimental Study on Autothermal Reformation of Methanol with Various Oxygen to Methanol Ratios for Fuel Cell Applications (연료전지용 메탄올 자열 개질기의 산소-메탄올 비율에 따른 성능 실험)

  • Hwang, Ha-Na;Shin, Gi-Soo;Jang, Sang-Hoon;Choi, Kap-Seung;Kim, Hyung-Man
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.35 no.4
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    • pp.391-397
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    • 2011
  • The use of Hydrogen as a fuel is receiving considerable attention and as a result, research on novel methods of hydrogen production is necessary so that the hydrogen demands in the future can be satisfied. This study presents experimental data on methanol Autothermal Reformation that quantifies the relationship between the oxygen-to-methanol ratio ($O_2/CH_3OH$) and reformer efficiency. For each catalyst configuration, the $O_2/CH_3OH$ was varied from 0.1 to 0.4, with an increment of 0.05, to investigate the effects of $O_2/CH_3OH$ on the reactor performance, including temperature profile, conversion, and efficiency. $O_2/CH_3OH$ was increased from 0.15 to 0.20, and the catalyst bed temperature increased by $235^{\circ}C$ to approximately $550^{\circ}C$. The catalyst bed temperature increased with increasing $O_2/CH_3OH$ as the reaction shifted from endothermic to exothermic reaction and as a result, excess heat, which raised the reactor temperature, was generated. The reactor performance was shown to be highly dependent on $O_2/CH_3OH$. The optimum $O_2/CH_3OH$ = 0.30 found in the experimental tests is 30% higher than the theoretical optimum of 0.23. This is attributed to a combination of factors such as the concentrations of the $O_2$ and $CH_3OH$ gas, reaction rate, catalyst effects, heat loss from the reactor, and the difference between the actual amounts of reaction products formed and the theoretical amounts of the reaction products.

Freud's Moses-study and the Principle of Mythological Hermeneutic: Its Political Theological Interpretation Through Jan Assmann's Theory of Cultural Memory (프로이트의 모세-가설과신화해석학의 원리: 얀 아스만의 문화적 기억이론을 통한 정치신학적 해석)

  • KIM, JIN
    • Journal of Korean Philosophical Society
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    • no.119
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    • pp.129-159
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    • 2017
  • The study of Freud's Moses and the background of the establishment of monotheism has become a subject of attention in the new atmosphere of the spreading of political theology and the recent rediscovery of Egyptology. This paper examines the publishing background and intentions of Freud's last book, Moses and Monotheism. And it will emphasize the fact that the Moses-Egyptian theory and his criticism of monotheism hid political theological intentions to prevent the spread of anti-Semitism in Nazi Germany. According to the Egyptologist Jan Assmann, there is a difference in that Moses' Judaism is monotheism, but Akhenaten's Aton-religion is a cosmotheism, and while Freud emphasizes Moses the 'historical figure' of that name, Assmann refers to Moses as a 'mnemohistorical figure.' Just as Freud said that the source of Jewish hatred is in Moses himself who established monotheism, Assmann argues also, monotheism is based on the so-called "Mosaic distinction" that distinguishes between true religion and false religion, thus it is possible to dismantle oppression and violence through the abolition of the Mosaic distinction. Assmann estimates that Freud had a clear stance to stop the spread of anti-Semitism as "the most explicit opponent of the Mosaic distinction." While anti-Semitic hatred spread to Christians in the Nazi era, Freud regards the real founder of Christianity, a jew Paul, as both a "Judaism destroyer" and a "successor to Judaism." At this point, Taubes began to see Paul's theology from a political theological point of view, and Assmann succeeded it. The "historical Moses" described by Freud are not "Prophet Moses" but "Moses as lawmaker and political reformer", and Jewish hatred has arisen in his distinction. Thus, Freud's monotheistic criticism as "disintegration by historical reduction"(Nietzsche) has political theological power. Just as Taubes interpreted Paul as a political theologian, Assmann found political theological elements in Freud's criticism of monotheism.