• Title/Summary/Keyword: anode water

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An Experimental Study of Verification for PEMFC's 1-Dimensional Simulation (PEMFC 1차원 시뮬레이션 검증을 위한 실험적 연구)

  • Moon, Cheor-Eon;Ahn, Seong-Yool;Yang, Jang-Sik;Choi, Gyung-Min;Kim, Duck-Jool
    • 한국신재생에너지학회:학술대회논문집
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    • 2007.06a
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    • pp.191-195
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    • 2007
  • In this study, we estimated the performance of PEMFC's unit cell as changing operating temperature in different inlet humidity condition at cathode side but anode dry, and tried to match experimental results with 1-dimensional simulation. We used $Nafion^{\circledR}112$ membrane and a self-manufactured PEMFC with active area of $25cm^{2}$ was used in this study. The range of operating temperature was $40{\sim}70^{\circ}C$ and oxygen through bubbled humidity chamber was supplied $0{\sim}80$% humidity condition as changing water temperature in humidity chamber. For figuring out governing equations, represent water contents in electrolyte membrane, the linear forward difference method was applied about time progress and quadratic central difference method was used about space progress. It was assumed that pressure terms were linearly changed due to thin electrolyte membrane. In low operating temperature condition, $40{\sim}60^{\circ}C$, increasing temperature rarely effected cell performance but we can see performance drop at $70^{\circ}C$. By modifying Henrry's constant and/or diffusion coefficient, the modified one-dimensional model was accomplished for calculation.

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Treatment of reactive dyes wastewater by electrochemical method (전기화학적인 방법에 의한 반응성 염료폐수의 처리)

  • Yu, Jae-Jeong;Jeon, Seong-Hwan;Park, Jeong-Min;Jeong, Jae-Ho;Park, Sang-Jeong;Min, Kyung-Sok
    • Journal of Korean Society on Water Environment
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    • v.18 no.3
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    • pp.245-251
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    • 2002
  • Reactive dyes waste water, a toxic and refractory pollutant, was treated by an electrochemical method using $Ti/IrO_2$ as anode and Stainless Steel 316 as cathode. In this technique, sodium chloride as an electrolyte was added. A number of experiments were run in a batch system. Artificial samples (reactive blue 19, red 195, yellow 145) were used. Operation parameters, such as supporting electrolyte concentration, current density, pH and sample concentration have been investigated for their influences on COD and color removal efficiencies during electrolysis. After 5 and 90 minites of eletrolysis, color was reduced by 51.5% and 98.9% respectively. Under the condition of current density $10A/dm^2$, NaCl concentration 12mg/l and pH 3, 62.9% of $COD_{Cr}$ was removed after electrolysis for 90 minites. The optimum condition of color removal and COD reduction in this work was found to be the following : pH 3, sodium chloride concentration 20g/l, current density $10A/dm^2$. As a result, we confirmed to be effective to color removal and reduction of refractory organic material.

Thermal managing effects by cooling channels on performance of a PEMFC (냉각채널 열관리에 따른 고분자연료전지의 성능영향 연구)

  • Sohn, Young-Jun;Kim, Min-Jin;Park, Gu-Gon;Kim, Kyoung-Youn;Lee, Won-Yong
    • 한국신재생에너지학회:학술대회논문집
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    • 2009.06a
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    • pp.373-373
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    • 2009
  • Relative humidity, membrane conductivity and water activity are critical parameters of polymer electrolyte membrane fuel cells (PEMFC) for high performance and reliability. These parameters are closely related with temperature. Moreover, the ideal values of these parameters are not always identical along the channels. Therefore, the cooling channel design and its operating condition should be well optimized along the all location of the channels. In the present study, we have performed a numerical investigation on the effects of cooling channels on performance of a PEMFC. Three-dimensional Navier-Stokes equations are solved with the energy equation including heat generated by the electrochemical reactions in the fuel cell. The present numerical model includes the gas diffusion layers (GDL) and serpentine channels for both anode and cathode gas flows, as well as cooling channels. To accurately predict the water transport across the membrane, the distribution of water content in the membrane is calculated by solving a nonlinear differential equation with a nonlinear coefficient, i.e., the water diffusivity which is a function of water content as well as temperature. Main emphasis is placed on the heat transfer between the solid bipolar plate and coolant flow. The present results show that local current density is affected by cooling channels due to the change of the oxygen concentration and the membrane conductivity as well as the water content. It is also found that the relative humidity is influenced by the generated water and the gas temperature and thus it affects the distribution of fuel concentration and the conductivity of the membrane, ultimately fuel cell performance. Unit-cell experiments are also carried out to validate the numerical models. The performance curves between the models and experiments show reasonable results.

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An Electrochemical Evaluation of the Corrosion Property on the Welded Zone of Sea Water Pipe according to Welding Materials (용접 재료 별 해수 배관 용접부위의 부식 특성에 관한 전기화학적 평가)

  • Kim, Jin-Gyeong;Won, Chang-Uk;Jo, Hwang-Rae;Lee, Myung-Hoon;Kim, Yun-Hae;Moon, Kyung-Man
    • Journal of Ocean Engineering and Technology
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    • v.21 no.5
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    • pp.39-46
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    • 2007
  • The sea water pipe of a ship's engine room is a severely corrosive environment caused by fast flawing sea water containing chloride ions and high conductivity. Therefore, leaking of sea water may occur as a result of local corrosion of the welded zone. Leaking is usually controlled by various welding methods. In this study, when the sea water pipe is welded with certain welding methods and welding electrodes, the corrosion resistance of WM (Welding metal) and HAZ (Heat affected zone) was investigated using electrochemical methods. Although the corrosion potential of the HAZ is higher than that of WM, the corrosion resistance of WM is superior to HAZ. However, when WM and HAZ are both opened to the sea water, the WM part with the anode was more seriously corroded than was the HAZ of the cathode by performance of a galvanic cell due to difference of the corrosion potential between HAZ and WM. In particular TIG welding showed relatively good results in corrosion resistance of both HAZ and WM compared to other welding methods.

Degradation of MEA and Characteristics of Outlet Water According to Operation Condition in PEMFC (고분자 전해질 연료전지 구동 조건에 따른 MEA 열화 및 배출수 특성)

  • Hwang, Byungchan;Lee, Sehoon;Na, Il-Chai;Park, Kwonpil
    • Korean Chemical Engineering Research
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    • v.55 no.4
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    • pp.478-482
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    • 2017
  • Humidity control of proton exchange membrane fuel cell(PEMFC) is very important control condition during driving. In terms of water management, low humidification conditions are advantageous, and high humidification is advantageous in terms of drainage utilization and energy efficiency. In this study, the characteristics of outlet water in low humidification and high humidification process were studied in terms of utilization of discharged water. Since the impurities in the effluent are generated during the degradation of the membrane and the electrode assembly(MEA), degradation of the MEA under low humidification and high humidification conditions was also studied. The rate of radical generation was high at low humidification condition of the anode RH 0%, which showed that it was the main cause of the degradation of the polymer membrane. Analysis of effluent showed low concentration of fluoride ion concentration of about 20 ppb at high humidification (both electrodes RH 100%) and 0.6 V, which was enough to be used as the feed water for electrolysis. Very low concentration of platinum below 0.2 ppb was detected in the condensate discharged from the high humidification condition.

Optimization of Operating Parameters and Components for Water Electrolysis Using Anion Exchange Membrane (음이온 교환막 알칼리 수전해를 위한 운전 조건 및 구성요소의 최적화)

  • Jang, Myeong Je;Won, Mi So;Lee, Kyu Hwan;Choi, Sung Mook
    • Journal of the Korean institute of surface engineering
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    • v.49 no.2
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    • pp.159-165
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    • 2016
  • The hydrogen has been recognized as a clean, nonpolluting and unlimited energy source that can solve fossil fuel depletion and environmental pollution problems at the same time. Water electrolysis has been the most attractive technology in a way to produce hydrogen because it does not emit any pollutants compared to other method such as natural gas steam reforming and coal gasification etc. In order to improve efficiency and durability of the water electrolysis, comprehensive studies for highly active and stable electrocatalysts have been performed. The platinum group metal (PGM; Pt, Ru, Pd, Rh, etc.) electrocatalysts indicated a higher activity and stability compared with other transition metals in harsh condition such as acid solution. It is necessary to develop inexpensive non-noble metal catalysts such as transition metal oxides because the PGM catalysts is expensive materials with insufficient it's reserves. The optimization of operating parameter and the components is also important factor to develop an efficient water electrolysis cell. In this study, we optimized the operating parameter and components such as the type of AEM and density of gas diffusion layer (GDL) and the temperature/concentration of the electrolyte solution for the anion exchange membrane water electrolysis cell (AEMWEC) with the transition metal oxide alloy anode and cathode electrocatalysts. The maximum current density was $345.8mA/cm^2$ with parameter and component optimization.

Effect of Temperature on Electrochemical Degradation of Membrane in PEMFC (PEMFC 고분자 막의 전기화학적 열화에 미치는 온도의 영향)

  • Lee, Ho;Kim, Taehee;Son, Ik Jae;Lee, Jong Hyun;Lim, Tae Won;Park, Kwonpil
    • Korean Chemical Engineering Research
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    • v.47 no.4
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    • pp.441-445
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    • 2009
  • Effect of temperature on membrane degradation in PEMFCs was studied. After cell operation at different temperatures($60{\sim}90^{\circ}C$) under accelerating degradation conditions(OCV, anode dry, cathode RH 65%) for 144 h, cell performance decreased from 12 to 35%. The results of FER in effluent water showed that this decrease in cell performance was caused by membrane degradation by the attack of $H_2O_2$ or oxygen radicals(${\cdot}OH$, $HO_2{\cdot}$) and that resulted in increase in gas crossover for radical formation. Radical formation on the electrode was confirmed by ESR. Activation energy of 66.2 kJ/mol was obtained by Arrhenius plot used to analyze the effect of temperature on membrane degradation. Increase of cell temperature enhanced gas crossover rate, radical formation rate and membrane degradation rate.

A Study of Multi-channel AFS for Marine Traffic Facilities (해양교통시설물용 다채널 AFS에 관한 연구)

  • Kim, Ji-Yoon;Lee, Ji-Young;Oh, Jin-Seok
    • Journal of Advanced Marine Engineering and Technology
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    • v.39 no.1
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    • pp.75-80
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    • 2015
  • After some period of time, the marine traffic facilities find problems caused by shellfish adhered to inside and inlet of the water column. Therefore, single-channel AFS(Anti-Fouling System) has been applied in order to minimize the deposition of shellfish. However, imbalance phenomenon of ionization of copper electrodes that are used for single-channel AFS appeared. This problem resulted in frequent replacement of anode. In this paper, multi-channel current control system has been developed, as well as the related hardware has been designed and fabricated. Further, experimental study has been undertaken to compare the application of single and multi- channel AFS. Through the sea experiments, it was possible to confirm that the copper electrode used for multi-channel AFS is uniformly ionized.

A study on temperature characteristic of the gases supplied to SOFC system by utilizing the ship exhaust gas (선박 배기가스 활용에 따른 SOFC 시스템 공급가스의 온도특성에 관한 연구)

  • Park, Sang-Kyun
    • Journal of Advanced Marine Engineering and Technology
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    • v.37 no.8
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    • pp.822-828
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    • 2013
  • Since the operating temperature of Solid Oxide Fuel Cell (SOFC) is high, the heat management of the gases supplied to fuel cell system is important. In this paper, the temperature characteristic of the gases supplied to the anode and the cathode of the fuel cell is studied in case of utilizing the waste heat contained in the ship exhaust gas as a heat source to heat up the fuel, gas and water supplied to a 500kW SOFC system for a ship power. For the fuel cell system proposed in this paper, the temperature of gases supplied to the anode and the cathode was the highest temperature at 963K when the exhaust gas of the fuel cell was utilized as the heat source for gases supplied to fuel cell system instead of utilizing the ship exhaust gas. In addition, the engine power did not effect on the temperature of gases supplied to the fuel cell stack.

Electrochemical Control of Metabolic Flux of Weissella kimchii sk10: Neutral Red Immobilized in Cytoplasmic Membrane as Electron Channel

  • PARK, SUN-MI;KANG, HYE-SUN;PARK, DAE-WON;PARK, DOO-HYUN
    • Journal of Microbiology and Biotechnology
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    • v.15 no.1
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    • pp.80-85
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    • 2005
  • Electrochemical control of the metabolic flux of W. kimchii sk10 on glucose and pyruvate was studied. The growing cell of W. kimchii sk10 produced 87.4 mM lactate, 69.3 mM ethanol, and 4.9mM lactate from 83.1mM glucose under oxidation condition of the anode compartment, but 98.9 mM lactate, 84.3mM ethanol, and 0.2 mM acetate were produced from 90.8 mM glucose under reduction condition of the cathode compartment for 24 h, respectively. The resting cell of W. kimchii sk10 produced 15.9 mM lactate and 15.2 mM acetate from 32.1 mM pyruvate under oxidation condition of the anode compartment, and 71.3 mM lactate and 3.8 mM acetate from 79.8mM pyruvate under reduction condition of the cathode compartment. The redox balance (NADH/$NAD^+$) of metabolites electrochemically produced from pyruvate was 1.05 and 18.76 under oxidation and reduction conditions, respectively. On the basis of these results, we suggest that the neutral red (NR) immobilized in bacterial membrane can function as an electron channel for the electron transfer between electrode and cytoplasm without dissipation of membrane potential, and that the bacterial fermentation of W. kimchii sk10 can be shifted to oxidized or reduced pathways by the electrochemical oxidation or reduction, respectively.