• Title, Summary, Keyword: reforming

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Preparation of perovskite-based catalysts and fuel injection system for high durability of diesel reforming (디젤 개질을 위한 페로브스카이트 구조 촉매와 연료주입 시스템의 개발)

  • Rhee, Junki;Park, Sangsun;Shul, Yong-Gun
    • 한국신재생에너지학회:학술대회논문집
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    • pp.115.2-115.2
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    • 2010
  • Autothermal reforming(ATR) processes of hydrocarbon liquids such as diesel fuels are spotlighted as methods to produce hydrogen for Fuel cell. However, the use of heavy hydrocarbons as feedstocks for hydrogen production causes some problems which increase the catalyst deactivation by the carbon deposition. Coking can be inhibited by increasing the water dissociation on the catalyst surface. This results in catastrophic failure of whole system. Performance degradation of diesel autothermal reforming leads to increase of undesirable hydrocarbons at reformed gases and subsequently decrease the performance. In this study, perovskite-based catalysts were investigated as alternatives to substitute the noble metal catalyst for the ATR of diesel. The investigated perovskite structure was based on LaCrO3. and metals were added at the A-site to enhance oxygen ion mobility, transition metals were doped on the B-site to enhance the reformation. Substituted Lanthanum chromium perovskite were made by aqueous combustion synthesis, which can produce high surface area. And for the homogeneous fuel supply, we made ultrasonic injection system for reforming. We compared durability of evaporation system and ultrasonic system for fuel injection.

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Methane-Steam Reforming Simulation for a High Temperature Solar Chemical Reactor (고온 태양열 화학 반응기에서의 메탄-수증기 개질반응 시뮬레이션)

  • Ko, Jo-Han;Seo, Tae-Beom
    • Journal of the Korean Solar Energy Society
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    • v.29 no.1
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    • pp.44-49
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    • 2009
  • Steam reforming of methane in the high temperature solar chemical reactor bas advantage in its heating method. Using concentrated solar energy as a heating source of the reforming reaction can reduce the $CO_2$ emission by 20% compared to hydrocarbon fuel. In this paper, the simulation result of methane-steam reforming on a high temperature solar chemical reactor(SCR) using Fluent 6.3.26 is presented. The high temperature SCR is designed for the Inha Dish-1, a Dish type solar concentrator installed in Songdo city. Basic SCR performance factors are referred to the former researches of the same laboratory. Inside the SCR porous metal is used for a receiver/reactor. The porous metal is carved like a dome shape on the incident side to increase the heat transfer. Also, ring-disc set of baffle is inserted in the porous metal region to increase the path length. Numerical and physical models are also used from the former researches. Methane and steam is mixed with the same mole fraction and injected into the SCR. The simulation is performed for a various inlet mass flow rate of the methane-steam mixture gas. The result shows that the average reactor temperature and the conversion rate change appreciably by the inlet mass flow rate of 0.0005 kg/s.

Simulation of the Hydrogen Conversion Rate Prediction for a Solar Chemical Reactor (태양열 화학반응기의 수소전환효율 예측 시뮬레이션)

  • Ko, Jo-Han;Seo, Tae-Beom
    • 한국태양에너지학회:학술대회논문집
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    • pp.294-299
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    • 2008
  • Steam reforming of methane is the most wide spread method for hydrogen production. It has heed studied more than 60 years. methane reforming has advantages in technological maturity and economical production cost. Using a high-temperature solar thermal energy is an advanced technology in Steam reforming process. The synthesis gas, the product of the reforming process, can be applied directly for a combined cycle or separated for a hydrogen. In this paper, hydrogen conversion rate of a solar chemical reactor is calculated using commercial CFD program. 2 models are considered. Model-1 is original model which is designed from the former researches. And model-2 is ring-disk set of baffle is inserted to enhance the performance. The solar chemical reactor has 3 inlet nozzle at the bottom of the side wall near quartz glass and an exit is located at the top. Methane and steam is premixed with 50:50 mole fraction and goes into the inside. Passing through the porous media, the reactants are conversed into hydrogen and carbon monoxide.

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Synthesis of Thin Film Type Cu/ZnO Nanostructure Catalysts for Development of Methanol Micro Reforming System (마이크로 개질기 개발을 위한 박막형 Cu/ZnO 나노구조 촉매 합성)

  • Yeo, Chan Hyuk;Kim, Yeon Su;Im, Yeon Ho
    • Transactions of the Korean hydrogen and new energy society
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    • v.24 no.3
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    • pp.193-199
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    • 2013
  • In this work, thin film type Cu/ZnO nanostructure catalysts were fabricated by several synthetic routes in order to maximize the performance of the micro reforming system. For this work, various Cu/ZnO nanostructure catalysts could be synthesized by means of four approaches which are chemical vapor method, wet solution method and their hybrid method. The reforming performance of these as-synthetic catalysts was evaluated as compared to the conventional catalysts. Among the as-synthetic nanostructures, sphere type catalysts with specific surface of $18.6m^2/g$ showed the best performance of hydrogen production rate of 30ml/min at the feed rate of 0.2ml/min. This work will give the first insight on thin film type Cu/ZnO nanostructure catalyst for micro reforming system for hydrogen production of portable electronic systems.

A Simulation Study of the Effect of Microstructural Design on the Performance of Solid Oxide Fuel Cells With Direct Internal Reforming (내부개질형 고체산화물 연료전지의 마이크로 전극구조가 성능에 미치는 영향에 관한 해석적 연구)

  • Sohn, Sangho;Nam, In Hyun
    • Transactions of the Korean hydrogen and new energy society
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    • v.24 no.5
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    • pp.401-412
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    • 2013
  • The paper is to study on the simulation of the micro/macroscale thermo-electrochemical model of a single cell of anode-supported SOFC with direct internal reforming. The coupled heat and mass transport, electrochemical and reforming reactions, and fluid flow were simultaneously simulated based on mass, energy, charge conservation. The micro/macroscale model first calculates the detailed electrochemical and direct internal reforming processes in porous electrodes based on the comprehensive microscale model and then solve the macroscale processes such as heat and mass transport, and fluid flow in SOFCs with assumption of fully-developed flow in gas channel. The simulation results evaluate the overall performance by analyzing distributions of mole fraction, current density, temperature and microstructural design in co/counter flow configurations.

A Study on the Reaction Characteristics of Steam Reforming Reaction over Catalyzed Porous Membrane (다공성 촉매 분리막을 이용한 수증기 개질 반응 특성 연구)

  • Hong, Sung Chang;Lee, Sang Moon
    • Applied Chemistry for Engineering
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    • v.25 no.2
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    • pp.198-203
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    • 2014
  • In this study, steam reforming reaction and surface characteristics of Ni metal foam plate were investigated. Valence state of Ni could be changed by pretreatment, and metallic Ni species exposed on surface as a active site play important role in steam reforming reaction. Porous catalytic membrane also was prepared by mixing of Ni metal foam plate and Ni-YSZ catalyst to control the pore size and assign the catalytic function in Ni metal foam plate. In SEM analysis results, Pore size of Ni metal foam plate could be controlled and Ni-YSZ catalyst well dispersed on surface. Ni based porous catalytic membrane had a similar steam reforming activity regardless of space velocity.

Ethanol Steam Reforming Reaction for a Clean Hydrogen Production and its Application in a Membrane Reactor (청정수소생산을 위한 에탄올 수증기개질반응 및 막반응기에서의 응용)

  • Lim, Hankwon
    • Clean Technology
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    • v.19 no.4
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    • pp.379-387
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    • 2013
  • Ethanol steam reforming reaction considered as a clean hydrogen production method is introduced in this paper. Reactivity and reaction rate equation of ethanol steam reforming reaction using various catalysts, reaction temperature, and molar ratio of ethanol and water will be discussed. In addition to introducing a membrane reactor combining a reactor and a separator, the effect of the use of a membrane reactor on an ethanol conversion and hydrogen yield will be compared to those from a conventional packed-bed reactor.

Degradation Comparison of Hydrogen and Internally Reformed Methane-Fueled Solid Oxide Fuel Cells

  • Kim, Young Jin;Lee, Hyun Mi;Lim, Hyung-Tae
    • Journal of the Korean Ceramic Society
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    • v.53 no.5
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    • pp.483-488
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    • 2016
  • Anode supported solid oxide fuel cells (SOFCs), consisting of Ni+YSZ anode, YSZ electrolyte, and LSM+YSZ cathode, were fabricated and constant current tested with direct internal reforming of methane (steam to carbon ratio ~ 2) as well as hydrogen fuel at $800^{\circ}C$. The cell, operated under direct internal reforming conditions, showed relatively rapid degradation (~ 1.6 % voltage drop) for 95 h; the cells with hydrogen fuel operated stably for 170 h. Power density and impedance spectra were also measured before and after the tests, and post-test analyses were conducted on the anode parts using SEM / EDS. The results indicate that the performance degradation of the cell operated with internal reforming can be attributed to carbon depositions on the anode, which increase the resistance against anode gas transport and deactivate the Ni catalyst. Thus, the present study shows that direct internal reforming SOFCs cannot be stably operated even under the condition of S/C ratio of ~ 2, probably due to non-uniform mixture (methane and steam) gas flow.

Performance of Solid Oxide Fuel Cells with Direct Internal Reforming of Methane

  • Kim, Young Jin;Lim, Hyung-Tae
    • Journal of the Korean Ceramic Society
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    • v.52 no.5
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    • pp.325-330
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    • 2015
  • Performance of solid oxide fuel cells (SOFCs), in comparison with that under hydrogen fuel, were investigated under direct internal reforming conditions. Anode supported cells were fabricated with an Ni+YSZ anode, YSZ electrolyte, and LSM+YSZ cathode for the present work. Measurements of I-V curves and impedance were conducted with S/C (steam to carbon) ratio of ~ 2 at $800^{\circ}C$. The outlet gas was analyzed using gas chromatography under open circuit condition; the methane conversion rate was calculated and found to be ~ 90% in the case of low flow rate of methane and steam. Power density values were comparable for both cases (hydrogen fuel and internal steam reforming of methane), and in the latter case the cell performance was improved, with a decrease in the flow rate of methane with steam, because of the higher conversion rate. The present work indicates that the short-term performance of SOFCs with conventional Ni+YSZ anodes, in comparison with that under hydrogen fuel, is acceptable under internal reforming condition with the optimized fuel flow rate and S/C ratio.

Neurodevelopmental Problems in Non-Syndromic Craniosynostosis

  • Shim, Kyu-Won;Park, Eun-Kyung;Kim, Ju-Seong;Kim, Yong-Oock;Kim, Dong-Seok
    • Journal of Korean Neurosurgical Society
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    • v.59 no.3
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    • pp.242-246
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    • 2016
  • Craniosynostosis is the premature fusion of calvarial sutures, resulting in deformed craniofacial appearance. Hence, for a long time, it has been considered an aesthetic disorder. Fused sutures restrict growth adjacent to the suture, but compensatory skull growth occurs to accommodate the growing brain. The primary goal for the management of this craniofacial deformity has been to release the constricted skull and reform the distorted shape of the skull vault. However, the intellectual and behavioral prognosis of affected children has also been taken into consideration since the beginning of the modern era of surgical management of craniosynostosis. A growing body of literature indicates that extensive surgery, such as the whole-vault cranioplasty approach, would result in better outcomes. In addition, the age at treatment is becoming a major concern for optimal outcome in terms of cosmetic results as well as neurodevelopment. This review will discuss major concerns regarding neurodevelopmental issues and related factors.