• Korean Chemical Engineering Research
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• v.50 no.4
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• pp.690-695
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• 2012

Gas hydrate is an inclusion compound consisting of water and low molecular weight gases, which are incorporated into the lattice structure of water. Owing to its promising aspect to application technologies, gas hydrate has been widely studied recently, especially $CO_2$ hydrate for the CCS (Carbon Capture and Storage) issue. The key point of $CO_2$ hydrate technology for the CCS is how to produce gas hydrate in an efficient and economic way. In this study, we have tried to study the characteristic of gas hydrate formation using micro-sized ice through an ultrasonic nozzle which generate 2.4 MHz frequency wave. $CO_2$ as a carrier gas brings micro-sized mist into low-temperature reactor, where the mist and carrier gas forms $CO_2$ hydrate under $-55^{\circ}C$ and atmospheric pressure condition and some part of the mist also remains unreacted micro-sized ice. Formed gas hydrate was average 10.7 of diameter at average. The starting ice particle was set to constant pressure to form $CO_2$ hydrate and the consumed amount of $CO_2$ gas was simultaneously measured to calculate the conversion of ice into gas hydrate. Results showed that the gas hydrate formation was highly suitable because of its extremely high gas-solid contact area, and the formation rate was also very high. Self-preservation effect of $CO_2$ hydrate was confirmed by the measurement of $CO_2$ hydrate powder at normal and at pressed state, which resulted that this kind of gas storage and transport could be feasible using $CO_2$ hydrate formation.

• Journal of computational fluids engineering
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• v.19 no.3
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• pp.77-84
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• 2014

The lattice Boltzmann (LB) method has been used to simulate rarefied gas flows in a micro-system as an alternative tool. However, previous results were mainly focused on a simple geometry with flat walls because the LB method is modeled on uniform Cartesian lattices. When previous boundary conditions for the microflows are applied to curved walls, the use of them requires approximation of the curved boundary by a series of stair steps, and introduces additional errors. For macroflows, no-slip curved wall boundary treatments have been developed remarkably in order to overcome these limits. However, the investigations for the slip curved wall boundary have rarely been performed for microflows. In this work, a curved boundary treatment of the LB method for a slip flow has been introduced. The results of the LB method for 2D microchannel and 3D microtube flows are in excellent agreement with the analytical solutions.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.10
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• pp.1598-1602
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• 2004

In this paper, we report a microthermostat using PDMS (poly-dimethylsiloxane) and glass. This PDMS/glass chip is able to maintain constant temperature that is necessary for restriction enzyme reaction. Since PDMS is the low-cost and the mass-producible material and has very good biochemical compatibility, PDMS chip has more benefit than general Si chip. Heater was made of Au wiring patterned on Pyrex glass. A reaction chamber has a capacity of about 3 ${mu}ell$. We performed a restriction enzyme reaction by using the fabricated microthermostat and conventional method. Then, with the electrophoresis, we made a comparison between the result from the micro reactor and the one from conventional method.

• Proceedings of the Korean Fiber Society Conference
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• 2003.10a
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• pp.37-38
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• 2003

Melamine resin microcapsules with mean sizes from 500 to 600 m were prepared by using a micro-tubular reactor (microreactor) with toluene and sodium dodecylsulfate (SDS) as emulsifiers. Conventional stirring method with telomeric surfactant in place of SDS produced microcapsules with mean sizes from 100 to 200 nm. Preparation by means of microreactor method with telomeric surfactant gave microcapsules with sizes below 200 nm in narrow particle size distribution. TG analysis revealed that the microcapsules contained 50 wt% of toluene.

• Proceedings of the Korean Nuclear Society Conference
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• 1997.05a
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• pp.15-20
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• 1997

We present the results HELIOS verification against VENUS PWR critical experiments loaded with high plutonium content mixed oxides fuels. The effective multiplication factors are calculated to be slightly supercritical within an acceptable error bound. In the prediction of power shape, HELIOS results are in close agreement with the measured values. The RMS errors of re-normalized calculated fission rate distribution are less than 1.4 % with either explicit or implicit models or micro tubes/rods in each fuel assembly for both ALL-MOX and GD-MOX mock-up cores.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.32 no.8
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• pp.624-632
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• 2008

In this research, we developed new PDMS-glass based microbiochip consisted of the micromixer and microreactor for DNA ligation. The micromixer was composed of a straight channel integrated with nozzles and pillars, and the microreactor was composed of a serpentine channel. We coated the PDMS chip surface with the 0.25wt.% PVP solution to prevent the bubble generation which was caused by the hydrophobicity of the PDMS. The new micomixer was passive type and the mixing was enhanced by a convective diffusion using the nozzle and pillar. The 10.33mm long micromixer showed the good mixing efficiency of 87.7% at 500 l/min flow rate. We could perform the DNA ligation successfully in the microbiochip, and the ligation time was shortened from 4 hours in conventional laboratory method to 5 min in the microbiochip.

• 한국연소학회:학술대회논문집
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• 2001.06a
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• pp.46-52
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• 2001

In this study, the generation of oxygen-free gas using catalytic combustion for industrial applications is explained ; heat treatment and copper annealing. For the experiment, Pd catalysts were determined by testing their catalytic activities over LPG in a micro-reactor. Combustion characteristics for the generation of oxygen-free atmospheric gas and the effect of flue gas upon surface oxidation were estimated form this experiment. As a result of the experimental investigation, we can state that the catalytic combustion could generate oxygen-free atmospheric gas suitable for industrial applications, but vapor produced by combustion process must be carefully considered as a new factor of surface oxidation.

• 한국연소학회:학술대회논문집
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• 1999.10a
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• pp.63-69
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• 1999

The heat exchanger using the catalytic combustion can be applied to petrochemical processes and to VOC incineration facilities. In this work, the experiment for a new fin typed catalytic heat exchanger was conducted. Catalysts for the heat exchanger were determined by testing their catalytic activities over LPG in a micro-reactor. Based on experimental results of the fin typed catalytic heat exchanger, a small scaled heat exchange system was made to test its feasibility as a reboiler used in petrochemical processes. The results showed that the catalytic heat exchanger could combust off-gases effectively and at the same time could recover completely heat produced by catalytic combustion.

• Proceedings of the KAIS Fall Conference
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• 2011.12b
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• pp.496-498
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• 2011

본 논문에서는 알루미늄 드로스를 재활용하여 생성 된 수산화알루미늄을 이용하여 질소산화물 제거 SCR 촉매를 제조하였다. 현재 상용중인 촉매와 화학적 특성과 질소산화물 제거 효율을 비교하기 위해 동일 타입의 하니컴 형태의 $V_2O_5-WO_3-TiO_2-Al_2O_3$ SCR 촉매를 제조하였으며, XRF와 BET를 사용하여 화학적 특성을 평가 비교하였다. 또한 MR(Micro Reactor)을 이용하여 $350^{\circ}C$와 $450^{\circ}C$에서 질소산화물 제거 평가를 실시하였으며, 평가 결과 80~90%의 제거 효율을 확인하였다.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.368-371
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• 2008

An extensometer system to measure strain and displacement of cylindrical fatigue specimen in a autoclave of high temperature and high pressure environment has been developed by KEPRI. The extensometer reads the displacement caused by fatigue loads at the target length of the specimen installed inside the autoclave. The performance of the extensometer were tested at 15MPa, $315^{\circ}C$ of a operating pressurized water reactor. Two LVDT's of magnet type were connected to the extensometer and used for converting the fatigue displacement to electronic signal. The device is being used for developing environmental fatigue curve of CF8M cast austenitic stainless steel (CASS) in the test condition of low cycle and low strain. This paper introduces the background and results of the development.