• Title/Summary/Keyword: membrane performances

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Study on Dynamic Characteristic & Performance of the Air Supply System for PEM Fuel Cell (고분자 전해질 연료 전지용 공기공급계의 동특성 및 성능에 대한 연구)

  • Lee, Hee-Sub;Kim, Olang-Ho;Lee, Yong-Bok
    • The KSFM Journal of Fluid Machinery
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    • v.9 no.6 s.39
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    • pp.45-53
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    • 2006
  • Turbo-blower as an air supply system is one of the most important BOP (Balance of Plant) systems for FCV(Fuel Cell Vehicle). For generating and blowing compressed air, the motor of air blower consumes maximum 25% of net power, and fuel cell demands a clean air. In this study, turbo-blower supported by air foil bearings is introduced as the air supply system used by 80kW proton exchange membrane fuel systems. The turbo-blower is a turbo machine which operates at high speed, so air foil bearings suit their purpose as bearing elements. Analysis for confirming the stability and endurance is conducted. The rotordynamic stability was predicted using the numerical analysis of air foil bearings and it is verified through experimental works. In spite of various transient dynamic situation, the turbo-blower had stable performances. After the performance test, results are presented. The normal power of driving motor has about 1.6 kW with the 30,000 rpm operating range and the flow rate of air has maximum 160 SCFM. The test results show that the aerodymic performance and stability of turbo-blower are satisfied to the primary goals.

Highly Durable Pt catalyst Supported on the Hybrid Carbon Materials for Polymer Electrolyte Membrane Fuel Cell (탄소계 복합담지체에 담지된 고내구성 고분자전해질 연료전지용 백금촉매)

  • Park, Hyang Jin;Hur, Seung Hyun
    • Journal of the Korean Electrochemical Society
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    • v.17 no.3
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    • pp.201-208
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    • 2014
  • A Pt catalyst ($Pt/G_xC_y$) supported on the hybrid supporting materials composed of graphene oxide (GO) and carbon black (C) was fabricated using polyol method to improve the durability of electrocatalysts. The electrochemical performances measured by cyclic voltammograms using three-electrode system revealed that the properly designed $Pt/G_xC_y$ catalyst exhibited higher durability than that of Pt/C catalyst without sacrificing an electrocatalytic acivity. In the oxygen reduction reaction (ORR) performed in acid solution with the rotating disk electrode, the $Pt/G_xC_y$ catalyst showed greater mass and area-specific activity than those of Pt/C catalyst.

Olefin Separation Performances and Coordination Behaviors of Facilitated Transport Membranes Based on Poly(styrene-b-isoprene-b-styrene)/Silver Salt Complexes

  • Lee, Dong-Hoon;Kang, Yong-Soo;Kim, Jong-Hak
    • Macromolecular Research
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    • v.17 no.2
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    • pp.104-109
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    • 2009
  • Solid-state facilitated, olefin transport membranes were prepared by complexation of poly(styrene-b-iso-prene-b-styrene) (SIS) block copolymer and silver salt. Facilitated olefin transport was not observed up to a silver mole fraction of 0.14, representing a threshold concentration, above which transport increased almost linearly with increasing silver salt concentration. This was because firstly the silver ions were selectively coordinated with the C=C bonds of PI blocks up to a silver mole fraction of 0.20, and secondly the coordinative interaction of the silver ions with the aliphatic C=C bond was stronger than that with the aromatic C=C bond, as confirmed by FT-Raman spectroscopy. Small angle X-ray scattering (SAXS) analysis showed that the cylindrical morphology of the neat SIS block copolymer was changed to a disordered structure at low silver concentrations ($0.01{\sim}0.02$). However, at intermediate silver concentrations ($0.15{\sim}0.20$), disordered-ordered structural changes occurred and finally returned to a disordered structure again at higher silver concentrations (>0.33). These results demonstrated that the facilitated olefin transport of SIS/silver salt complex membrancs was significantly affected by their coordinative interactions and nano-structural morphology.

Comparison and application method of seawater desalination pre-treatment process (해수담수화 전처리공정 비교 및 적용 방법)

  • Lim, Hwankyu;Kim, Seunghyun
    • Journal of Korean Society of Water and Wastewater
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    • v.33 no.6
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    • pp.437-446
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    • 2019
  • Reverse osmosis seawater desalination facilities can extend the cleaning cycle and replacement time of the reverse osmosis membrane by pretreatment process. Selection of pretreatment process depends on water quality. It was attempted in this study to select approriate pretreatment process for the Masan bay, which was high in particles and organic content. For this purpose, performances of pretreatment processes such as filter adsorber (FA), pore controllable fiber (PCF), and ultrafiltration (UF) were compared based on the silt density index (SDI). The SDI value of the filtrate should be less than 3. The study results showed that UF can produce the filtrate quality satisfying the requirement. However, the transmembrane pressure (TMP) of UF increased quickly, reaching 0.6 bar within 4 days. In order to secure stable operation, FA and PCF were combined with UF. The study results showed that combination of PCF and UF was able to extend the filtration duration (more than 2 months) until to reach TMP of 0.6 bar.

Comparison of Performances of Forward Osmosis and Membrane Distillation Processes for Shale Gas Plant Water Treatment (셰일가스 플랜트 용수 처리를 위한 정삼투(FO)와 막증발(MD) 공정의 성능 비교)

  • Koo, Jaewuk;Lee, Sangho;Shin, Yonghyun;Yun, Taekgeun
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.39 no.3
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    • pp.279-284
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    • 2015
  • As non-conventional oil resources such as shale gas have been widely developed, proper treatment of flowback and produced water is becoming important. However, application of conventional water treatment techniques is limited due to high concentration of pollutants such as oil and grease, organics, harmful chemicals, and inorganic ions. In this study, we examined the feasibility of using forward osmosis (FO) and air gap membrane distillation (AGMD) as novel treatment options for shale gas wastewater. Laboratory-scale FO and MD devices were fabricated and used for the experiments. Results showed that FO could be used to treat the synthetic wastewater. Using 5 M NaCl as the draw solution, the flux was approximately $6L/m^2-hr$ during the treatment of low range wastewater (TDS: 66,000 mg/L). Nevertheless, AGMD was more effective to treat high range wastewater (Total Dissolved Solid: 260,000 mg/L) than FO.

Thin-Film Composite (TFC) Membranes with Hydrophilic Ethyl Cellulose-g-poly(ethylene glycol) (EP) Substrates for Forward Osmosis (FO) Application (친수성을 가지는 에틸셀룰로스-폴리에틸렌글리콜 가지형 고분자의 정삼투 복합막 지지층으로의 응용)

  • Yu, Yun Ah;Kim, Jin-joo;Kang, Hyo;Lee, Jong-Chan
    • Korean Chemical Engineering Research
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    • v.54 no.4
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    • pp.510-518
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    • 2016
  • Ethyl cellulose-g-poly(ethylene glycol) (EP) was synthesized by esterification of carboxylic acid functionalized methoxy polyethylene glycol (MPEG-COOH) with ethyl cellulose (EC) in order to develop a hydrophilic substrate for thin-film composite (TFC) membrane in a forward osmosis (FO) system. A porous EP substrate, fabricated by a non-solvent induced phase separation method, was found to be more hydrophilic than the EC substrate due to the presence of polyethylene glycol (PEG) side chains in the EP. Since the EP substrate exhibits smaller water contact angles and higher porosity, the structural parameter (S) of TFC-EP is smaller than that of TFC-EC, indicating that internal concentration polarization (ICP) within porous substrates can occur less when TFC-EP is used as a membrane. For example, the water flux value of the TFC-EP is 15.7 LMH, whereas the water flux value of the TFC-EC is only 6.6 LMH. Therefore, we strongly believe that the TFC-EP could be a promising candidate with good FO performances.

Characteristics of Nafion Membranes with Pd Thin Films Deposited by DC Magnetron Sputtering Technique (DC마그네트론 스퍼터링으로 Pd박막 입힌 Nafion막의 특성)

  • Hwang, Gi-Ho;Cho, Won-Il;Cho, Byung-Won;Yoon, Sung-Ryul;Ha, Heung-Yong;Oh, In-Hwan;Kim, Kwang-Bum
    • Journal of the Korean Electrochemical Society
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    • v.5 no.2
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    • pp.68-73
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    • 2002
  • Modified polymer electrolyte membranes were fabricated by the applying dc magnetron sputter-deposited Pd thin layers on the surface of the $Nafion^{TM}$ membranes in argon atmosphere. The Pd thin films were characterized by investigating its morphology, methanol permeability, and protonic conductivity. The performance of a direct methanol fuel cell(DMFC) with the modifed polymer electrolyte membrane was also tested by the measurement of its currents and voltages under flowing methanol. The Pd thin film could be a barrier layer to methanol crossover, but the protonic conductivity of the modified polymer membrane was reduced. By using the modified polymer eletrolyte membranes, both the methanol permeability and the protonic conductivity were decreased with increasing the thickness of Pd thin film. However, the performances of DMFC were almost independent on the thickness of Pd thim films. The efffcts of methanol concentration in a feeding fuels on the protonic conductivity and the cell performance were also investigated.

Water Reuse of Sewage Discharge Water Using Fertilizer Drawn Forward Osmosis - Evaluating the Performance of Draw Solution - (비료 유도용액의 정삼투를 이용한 하수처리수의 재이용 - 유도용액의 성능 평가 -)

  • Kim, Seung-Geon;Lee, Ho-Won
    • Membrane Journal
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    • v.26 no.2
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    • pp.108-115
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    • 2016
  • This study is to evaluate the performance of draw solutions in the water reuse of sewage discharge water using fertilizer drawn forward osmosis. Feed water used in all experiments was the effluent from secondary sedimentation tank in activated sludge process. Considering osmotic pressure, solubility, and pH, $NH_4H_2PO_4$, KCl, $KNO_3$, $NH_4Cl$, $(NH_4)_2HPO_4$, $NH_4NO_3$, $NH_4HCO_3$, and $KHCO_3$ were screened from a comprehensive lists of fertilizer. Their performances were evaluated in terms of water permeate flux and reverse solute flux. KCl showed the highest average water flux followed by $NH_4Cl$, $NH_4NO_3$, $KNO_3$, $KHCO_3$, $NH_4HCO_3$, $NH_4H_2PO_4$, and $(NH_4)_2HPO_4$. Using KCl as draw solution, the average water permeate flux was 13.49 LMH. There was no big difference in osmotic pressure between the effluent from secondary sedimentation tank and deionized water. $NH_4H_2PO_4$ showed the lowest reverse solute flux followed by $NH_4Cl$, $(NH_4)_2HPO_4$, $KNO_3$, $NH_4HCO_3$, and $NH_4NO_3$. Using $NH_4H_2PO_4$ as draw solution, the reverse solute flux was $4.96{\times}10^{-3}mmol/m^2{\cdot}sec$.

Fabrication of Silane-crosslinked Proton Exchange Membranes by Radiation and Evaluation of Fuel Cell Performance (방사선을 이용한 실란 가교구조의 유/무기 복합 수소이온 교환막 제조 및 연료전지 성능 평가)

  • Lee, Ji-Hong;Sohn, Joon-Yong;Shin, Dong-Won;Song, Ju-Myung;Lee, Young-Moo;Nho, Young-Chang;Shin, Jun-Hwa
    • Polymer(Korea)
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    • v.36 no.4
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    • pp.525-530
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    • 2012
  • In this study, silane-crosslinked organic/inorganic composite membranes were prepared by simultaneous irradiation grafting of binary monomer mixtures (styrene and 3-(trimethoxysilyl)propyl methacrylate (TMSPM)) with various compositions onto a poly(ethylene-alt-tetraethylene) (ETFE) film and followed by sol-gel processing and sulfonation to provide a silane-crosslinked structure and a proton conducting ability, respectively. The Fourier transform infrared spectroscopy (FTIR) and thermo gravimetric analysis (TGA) were utilized to confirm the crosslinking of ETFE-g-PS/PTMSPM films. The prepared membranes with similar ion exchange capacity but a different TMSPM content were selected and their membrane properties were compared. The ETFE-g-PSSA/PTMSPM membranes were characterized by water uptake, dimensional stability, and proton conductivity after sulfonation. The membrane electrode assemblies (MEA) of the prepared membranes were fabricated and their single cell performances were measured.

Organic-inorganic Nanocomposite Adhesive with Improved Barrier Property to Water Vapor for Backsheets of Photovoltaic Modules (태양광모듈용 저가형 백시트 제조를 위한 고수분차단성 유무기 나노복합형 접착제)

  • Hwang, Jin Pyo;Lee, Chang Hyun
    • Membrane Journal
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    • v.25 no.6
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    • pp.530-537
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    • 2015
  • Photovoltaic (PV) modules are environmentally energy conversion devices to generate electricity via photovoltaic effect of semiconductors from solar energy. One of key elements in PV modules is "Backsheet," a multilayered barrier film, which determines their lifetime and energy conversion efficiency. The representative Backsheet is composed of chemically resistant poly(vinyl fluoride) (PVF) and cheap poly(ethylene terephthalate) (PET) films used as core and skin materials, respectively. PVF film is too expensive to satisfy the market requirements to Backsheet materials with production cost as low as possible. The promising alternatives to PVF-based Backsheet are hydrocarbon Backsheets employing semi-crystalline PET films instead of PVF film. It is, however, necessary to provide improved barrier property to water vapor to the PET films, since PET films are suffering from hydrolytic decomposition. In this study, a polyurethane adhesive with reduced water vapor permeation behavior is developed via a homogeneous distribution of hydrophobic silica nanoparticles. The modified adhesive is expected to retard the hydrolysis of PET films located in the core and inner skin. To clarify the efficacy of the proposed concept, the mechanical properties and electrochemical PV performances of the Backsheet are compared with those of a Backsheet employing the polyurethane adhesive without the silica nanoparticles, after the exposure under standard temperature and humidity conditions.