Suncheon, South Korea
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Lee S.-H.,Sunchon National University | Kim Y.-S.,ETIS Co. | Chu C.-H.,ETIS Co. | Na I.-C.,CNL Energy Co. | And 2 more authors.
Korean Chemical Engineering Research | Year: 2017

Recovery of sulfuric acid is very important after biomass converted to sugar by acid hydrolysis. In this work, the separation of sulfuric acid from sulfuric acid/glucose solution was studied by electrodiaysis. Three chamber method, which requires both anion membrane and cation membrane, is the most commonly used in the electrodialysis process, but two chamber method using only an anion membrane was the focus of this study. Sulfuric acid was perfectly separated from a mixture of 10-30 wt% glucose and 1-3 M sulfuric acid by electrodialysis using two chamber method. The separation rate of sulfuric acid lineary increased with higher current density when the affect of diffusion and convection of the membrane was small. Without electric energy, 45% of sulfuric acid was separated by diffusion and convection only. © 2017, Korean Institute of Chemical Engineers. All rights reserved.


Lee H.-R.,Sunchon National University | Park D.-H.,Sunchon National University | Ju W.,Sunchon National University | Na I.-C.,CNL Energy Co. | Park K.-P.,Sunchon National University
Korean Chemical Engineering Research | Year: 2017

Sodium borohydride, NaBH4, shows a number of advantages as hydrogen source for UAV PEMFC (Unmaned Aerial Vehicle Proton Exchange Membrane Fuel Cells). In order to use for UAV, the weight and volume of byproduct should be small after NaBH4 hydrolysis reaction. Therefore, the weight and volume of byproduct were studied after NaBH4 hydrolysis reaction using unsupported catalyst. The effect of catalyst type, concentration of NaBH4, concentration of NaOH and thickness of catalyst pack on the weight and volume of byproduct were studied. Most of byproduct was NaB(OH)4 and superficial volume of byproduct increased due to foam evolved from byproduct. The weight and volume of byproduct were not affected by concentration of NaOH used stabilizer. The weight of byproduct decreased as concentration of NaBH4 solution increased, but maximum volume of byproduct obtained at 23 wt% of NaBH4. Suitable defoaming agent reduced the volume of byproduct. © 2017, Korean Institute of Chemical Engineers. All rights reserved.


Jeong J.-H.,Sunchon National University | Song M.-H.,Sunchon National University | Chung H.-B.,Sunchon National University | Lee M.-S.,Sunchon National University | And 8 more authors.
Korean Chemical Engineering Research | Year: 2015

Recently, direct formic acid fuel cells (DFAFC) among direct liquid fuel cells is studied actively. Economical hydrocarbon membranes alternative to fluorinated membranes for DFAFC's membrane are receiving attention. In this study, characteristics of sulfonated poly(ether ether ketone, sPEEK) and sulfonated poly(arylene ether sulfone, PAES) membranes were compared with Nafion membrane at DFAFC operation condition. Formic acid crossover current density of hydrocarbon membranes were lower than that of Nafion 211 fluorinated membrane. I-V performance of sPEEK MEA(Membrane and Electrode Assembly) was similar to that of Nafion 211 MEA due to similar membrane resistance each other. sPEEK MEA with low formic acid crossover showed higher stability compared with Nafion 211 MEA.


Lee S.-H.,Sunchon National University | Hwang B.-C.,Sunchon National University | Lee H.-R.,Sunchon National University | Kim Y.-S.,Sunchon National University | And 5 more authors.
Korean Chemical Engineering Research | Year: 2015

Enzyme fuel cells were operated with cells composed of enzyme anode and PEMFC cathode. Enzyme anodes was fabricated by compression of a mixture of graphite particle, glucose oxidase(Gox) as a enzyme and ferrocene as a redox mediator, and then coated with Nafion ionomer solution. Performances of enzyme unit cell were measured with variation of anode manufacture factors, to find optimum condition of enzyme anode. Optimum pressure was 8.89MPa for enzyme anode pressing process. Highest power density was obtained at 60% graphite composition in enzyme anode. Optimum glucose concentration was 1.7 mol/l in anode substrate solution. The enzyme anode was stabilized by two times of deeping in Nafion solution for 1 sec.


Jung H.-S.,Sunchon National University | Oh S.-J.,Sunchon National University | Jeong J.-J.,Sunchon National University | Na I.-C.,Sunchon National University | And 4 more authors.
Korean Chemical Engineering Research | Year: 2015

Aluminum alloy was examined as a material of low weight reactor for hydrolysis of NaBH4. Aluminum is dissolved with alkali, but there is NaOH as a stabilizer in NaBH4 solution. To decrease corrosion rate of aluminum, decrease NaOH concentration and this result in loss of NaBH4 during storage of NaBH4 solution. Therefore stability of NaBH4 and corrosion of aluminum should be considered in determining the optimum NaOH concentration. NaBH4 stability and corrosion rate of aluminum were measured by hydrogen evolution rate. NaBH4 stability was tested at 20~50 °C and aluminum corrosion was measured at 60~90 °C. The optimum concentration of NaOH was 0.3 wt%, considering both NaBH4 stability and aluminun corrosion. NaBH4 hydrolysis reaction continued 200min in aluminum No 6061 alloy reactor with 0.3 wt% NaOH at 80~90 °C.


Lee H.-R.,Sunchon National University | Lee S.-H.,Sunchon National University | Hwang B.-C.,Sunchon National University | Na I.-C.,CNL Energy Co. | And 3 more authors.
Korean Chemical Engineering Research | Year: 2016

Recently, there are many efforts focused on development of more economical non-fluorinated membranes for PEMFCs (Proton Exchange Membrane Fuel Cells). In this study, to test the durability of sPEEK MEA (Membrane and Electrode Assembly), ADT (Accelerated Degradation Test) of MEA degradation was done at the condition that membrane and electrode were degraded simultaneously. Before and after degradation, I-V polarization curve, hydrogen crossover, electrochemical surface area, membrane resistance and charge transfer resistance were measured. Although the permeability of hydrogen through sPEEK membrane was low, sPEEK membrane was weaker to radical evolved at low humidity and OCV condition than fluorinated membrane such as Nafion. Performance after MEA degradation for 144 hours and 271 hours were reduced by 15% and 65%, respectively. It was showed that the main cause of rapid decrease of performance after 144 hours was shorting due to Pt/C particles in the pinholes.


Lee H.-R.,Sunchon National University | Na I.-C.,CNL Energy Co. | Park K.-P.,Sunchon National University
Korean Chemical Engineering Research | Year: 2016

Sodium borohydride, NaBH4, shows a number of advantages as hydrogen source for portable proton exchange membrane fuel cells (PEMFCs). Properties of NaBH4 hydrolysis reaction using unsupported Co-P-B Co-B, catalyst at high concentration NaBH4 solution were studied. In order to enhance the hydrogen generation yield at high concentration of NaBH4, the effect of catalyst type, NaBH4 concentration and recovery of condensing water on the hydrogen yield were measured. The yield of hydrogen evolution increased as the boron ratio increased in preparation process of Co-P-B catalyst. The hydrogen yield decreased as the concentration increased from 20 wt% to 25 wt% in NaBH4 solution during hydrolysis reaction using 1:5 Co-P-B catalyst. Maximum hydrogen yield of 96.4% obtained by recovery of condensing water and thinning of catalyst pack thickness in reactor using Co-P-B with Co-B catalyst and 25 wt% NaBH4 solution.


Jung H.-S.,Sunchon National University | Jo B.-J.,Sunchon National University | Lee J.-H.,CNL Energy Co | Lee H.-J.,CNL Energy Co | And 3 more authors.
Korean Chemical Engineering Research | Year: 2016

Proton Exchange Membrane Fuel Cells (PEMFC) instead of batteries is appropriate for long time flight of unmanned aero vehicles (UAV). In this work, NaBH4 hydrolysis system supplying hydrogen to PEMFC was studied. In order to decrease weight of NaBH4 hydrolysis system, enhancement of hydrogen yield, recovery of condensing water and maintenance of stable hydrogen yield were studied. The hydrogen yield of 3.4% was increased by controlling of hydrogen pressure in hydrolysis reactor. Condensing water formed during air cooling of hydrogen was recovered into storage tank of NaBH4 solution. In this process the condensing water dissolved NaBH4 powder and then addition of NaBH4 solution decreased system weight of 14%. NaBH4 hydrolysis system was stably operated with hydrogen yield of 96% by 2.0g Co-P-B catalyst for 10 hours at 2.0L/min hydrogen evolution rate.

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