• Transactions of the Korean hydrogen and new energy society
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• v.30 no.3
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• pp.227-236
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• 2019

In this work, preparation and characterizations of hybrid membranes containing sulfonated poly(arylene ether sulfone) (SPES) and sulfonated poly(vinylidene fluoride-co-hexafluoropropylene) (SPVdF-co-HFP) (20, 30 or 40 wt%) were carried out. The structure of hybrid membranes was confirmed using X-ray diffraction (XRD) analysis and the Fourier transform infrared (FT-IR) spectroscopy. The prepared SPAES/SPVdF-30 membrane exhibits higher ionic conductivity of 68.9 mS/cm at $90^{\circ}C$ and 100% RH. Besides, the other studies showed that the hybrid membrane has good oxidation stability, thermal stability, and mechanical stability. Thus, we believe that the prepared hybrid membrane is suitable for the development of membranes for fuel cell applications.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.4
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• pp.425-430
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• 2012

In this study, a preconverter of an MCFC for an emergency electric power supplier is numerically simulated to increase the hydrogen production from natural gas (methane). A commercial code is used to simulate a porous catalyst with a user subroutine to model three dominant chemical reactions-steam reforming, water-gas shift, and direct steam reforming. To achieve a fuel conversion rate of 10% in the preconverter, the required external heat flux is supplied from the outer wall of the preconverter. The calculated results show that the temperature distribution and chemical reaction are extremely nonuniform near the wall of the preconverter. These phenomena can be explained by the low heat conductivity of the porous catalyst and the endothermic reforming reaction. The calculated results indicate that the use of a compact-size preconverter makes the chemical reaction more uniform and provides many advantages for catalyst maintenance.

• KSBB Journal
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• v.11 no.2
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• pp.159-164
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• 1996

Transesterification of used frying oil was investigated to produce the bio-diesel oil. Experimental conditions included molar ratio of used frying oil to alcohol (1:3, 1:5 and 1:7), concentration of catalyst (0.5, 1.0 and 1.5 wt.%), ippe of catalyst(sodium melhoxide, NaOH and KOH), reaction temperature (30, 45 and $60^{\circ}C$), and types of alcohol(methanol, ethanol and butanol). The conversion of used frying oil increased with the alcohol mixing ratio and with the reaction temperature. The effect of the type of catalysts on conversion was not significant. The highest conversion was obtained when methanol was used as alcohol. Viscosity was a little higher with the ester product over grade #2 diesel oil. But the physical properties improved significantly with transesterification, resulting in similar fuel properties with those obtained for grade #2 diesel fuel.

• Transactions of the Korean hydrogen and new energy society
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• v.18 no.1
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• pp.32-39
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• 2007

CO oxidation and selective CO oxidation of $La_xCe_{1-x}Co_yCu_{1-y}O_{3-{\alpha}}$ perovskite(x=1, 0.9, 0.7. 0.5; y=1, 0.9, 0.7, 0.5) were investigated. For CO oxidation, catalytic activities were studied according to different preparation conditions such as pH and calcination temperature. The influence of the change of the $O_2$ concentration for selective CO oxidation was studied, too. The substitution of Ce for La improved the catalytic activity for CO oxidation and selective CO oxidation and best activity was observed for $La_{0.7}Ce_{0.3}CoO_3$ prepared at pH 11 and calcined at $600^{\circ}C$. The temperature of 90% CO conversion for CO oxidation using $La_{0.7}Ce_{0.3}CoO_3$ was $230^{\circ}C$. In contrast to the enhancement effect by Ce substitution, the partial substitution of Cu for Co in $LaCo_yCu_{1-y}O_{3-{\alpha}}$ decreased catalytic activities for CO oxidation reaction compared to that using $LaCoO_3$. For selective CO oxidation, the best CO conversion was 66% at $230^{\circ}C$ for $La_{0.7}Ce_{0.3}CoO_3$. The CO conversion of $La_{0.7}Ce_{0.3}CoO_3$ was greatly increased from 66% to 91% as increasing $O_2$ concentration from 1% to 2%.

• Transactions of the Korean hydrogen and new energy society
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• v.29 no.5
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• pp.473-482
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• 2018

To check applicability of recently developed new oxygen carrier for 0.5 MWth chemical looping combustion system, reactivity tests were carried out at high temperature and high pressure conditions. Pressure, temperature, gas velocity, $CH_4$ flow rate, and solid height were considered as operating variables. The new oxygen carrier (N016-R4) showed not only high fuel conversion but also high $CO_2$ selectivity within all the operating conditions in this study. The reactivity of N016-R4 particle was compared with previous oxygen carriers. The N016-R4 particle represented outstanding reactivity among 10 oxygen carriers in terms of fuel conversion and $CO_2$ selectivity.

• Resources Recycling
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• v.17 no.3
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• pp.35-41
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• 2008

The study of coking technology to upgrade oil sand bitumen which is considered as alternative fuel was performed by using thermogravity analyzer and delayed coking reactor(600ml). To analyzed and compared coking characteristics of oil sand bitumen, the reactivities of oil sand bitumen were measured in the TGA. At the temperature conditions of $400{\sim}550^{\circ}C$ and the temperature rising velocity of $50^{\circ}C/min$. the termination time of coking reaction and conversion efficiencies increased with an increase of bed temperature. However the increase rate decreased over $450^{\circ}C$. So the coking reaction with oil sand bitumen might be over $450^{\circ}C$. Also the termination time decreased with increasing the temperature rising velocity. But the content of coke increased with increasing temperature rising velocity. At the experiments in the delayed coker, the temperature condition at maximum oil yield was $475^{\circ}C$ and the fuel properties of oil from coking reaction was almost equal with conventional diesel. It was verified that the coking process might be useful process to upgrade the oil sand bitumem by using API and SIMDAS.

• Clean Technology
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• v.24 no.1
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• pp.63-69
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• 2018

The reduction reaction characteristics and physicochemical properties were studied for the selection of oxygen carrier, which is the core of the chemical looping combustion (CLC) technology. Fuel conversion and $CO_2$ selectivity of oxygen carrier according to the concentration of reducing gas and the reduction temperature using three kinds of oxygen carrier (SDN70, N018-R2, N016-R4) were measured and compared. In addition, Attrition Index (AI) and BET surface area were measured to analyze the attrition resistance and the surface characteristics of the oxygen carrier. As a result, it was confirmed that all three kinds of oxygen carrier were suitable for use in chemical roofing combustion system, and the best particle was determined to be N016-R4.

• 한국신재생에너지학회:학술대회논문집
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• 2007.06a
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• pp.169-171
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• 2007

A breaking layer was introduced to conventional decal transfer method in membrane electrolyte assembly fabrication for high catalyst transfer ratio. In this study, the modified decal transfer method with high catalyst transfer ratio was introduced and its performance is studied. The structural features of electrodes made by decal method were investigated using scanning electron microscopy and current-voltage polarization measurement.

• Transactions of the Korean Society of Automotive Engineers
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• v.8 no.1
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• pp.92-100
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• 2000

The model gas reaction tests were carried out to investigate the purification characteristics of methane on the exclusive catalyst for NGV. The experiment was conducted with the factors which affect the conversion efficiency of methane, such as Redox ratio, coexistence components of CO, MO, $H_2$O, precious metals and additives. The catalyst loaded with larger amount of pd and with additive La showed lower light-off temperature. In the presence of CO and NO, the conversion efficiency of methane was varied according to the kind of additive loaded. The conversion efficiency of methane was dropped for the catalyst loaded with La under lean air-fuel ratio, while it increased for the one loaded with Ti+Zr for the same condition. It was shown that the water vapor inhibited methane from oxidation by its poisoning on the surface of catalyst.

• Proceedings of the SAREK Conference
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• 2008.11a
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• pp.3-8
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• 2008

Effect of external heating rate on the conversion efficiency for the steam reforming of methanol is investigated numerically considering both heat and mass transfer of the species in a packed bed microreactor. In a results from the numerical simulation, the conversion efficiency of methanol has been obtained for the external heating rate. The axial variation of mole fraction of methanol has been additionally presented for several cases of external heating rates. The results show that for the constant inlet temperature condition the conversion efficiency of methanol increases with external heating rate over the range of operating conditions.