• 한국수소및신에너지학회논문집
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• 제23권1호
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• pp.73-82
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• 2012

A 2-dimensional heterogeneous reactor model was developed and simulated for a tube reactor of packed bed where the steam-$CO_2$ combined reforming reaction of natural gas proceeded to produce synthesis gas. Under the reactor feeding rate, 45 $Nm^3$/h, of the reactant gas stream, the 2-dimensional heterogeneous reactor model showed the similar results to those from the ASPEN simulator although there were some discrepancies between the two in the temperature and the $H_2$/CO ratio of the reformed gas at the reactor exit. The calculated enthalpy difference between the reformed gas at the reactor exit and the reactant gas fed to the reactor was closely correspondent to the total amount of heat transferred to the reactor interior from the furnace. This supports that the 2-dimensional heterogeneous reactor model was reasonably established and the numerical solution was properly obtained.

• 한국전기전자재료학회논문지
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• 제22권5호
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• pp.448-454
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• 2009

Hydrogen was produced from water plasma excited in high frequency (HF) inductively coupled tubular reactor. Mass spectrometry was used to monitor gas phase species at various process conditions, Water dissociation rate depend on the process parameters such as ICP power, $H_{2}O$ flow-rate and process pressure, Water dissociation percent in ICP reactor decrease with increase of chamber pressure, while increase with increase of ICP power and $H_{2}O$ flow rate. The effect of $CH_4$ gas addition to a water plasma on the hydrogen production has been studied in a HF ICP tubular reactor. The main roles of $CH_4$ additive gas in $H_{2}O$ plasma are to react with 0 radical for forming $CO_x$ and CHO and resulting additional $H_2$ production. Furthermore, $CH_4$ additives in $H_{2}O$ plasma is to suppress reverse-reaction by scavenging 0 radical. But, process optimization is needed because $CH_4$ addition has some negative effects such as cost increase and $CO_x$ emission.

• Korean Membrane Journal
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• 제5권1호
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• pp.68-74
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• 2003

Methane steam reforming (MSR) reaction for hydrogen production was studied in a membrane reactor (MR) using two tubular membranes, one Pd-based and one of porous alumina. A higher methane conversion than the thermodynamic equilibrium for a traditional reactor (TR) was achieved using MRs. The experimental temperature range was 350-500$^{\circ}C$; no sweep-gas was employed during reaction tests to avoid its back-permeation through the membrane and the steam/methane molar feed ratio (m) varied in the range 3.5-5.9. The best results (the difference between the MR conversion and the thermodynamic equilibrium was of about 7%) were achieved with the alumina membrane, working with the highest steam/methane ratio and at 450$^{\circ}C$. Silica membranes prepared at KRICT laboratories were characterized with permeation tests on single gases (N$_2$, H$_2$ and CH$_4$). These membranes are suited for H$_2$ separation at high temperature.

• Korean Chemical Engineering Research
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• 제51권1호
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• pp.116-120
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• 2013

관상의 광촉매 반응기에서 Pt가 담지된 $TiO_2$ 광촉매를 사용한 CO 전환 반응에 의해 CO를 제거하는 광촉매 공정에 대해 고찰하였다. $TiO_2$ 촉매에 Pt를 담지하는 방법, CO를 포함한 기체흐름속도, 기체흐름에 포함된 CO의 농도 그리고 기체의 수분함량이 CO를 $CO_2$로 전환하는 반응의 전환율에 미치는 영향을 검토하였다. Pt/$TiO_2$ 광촉매가 관의 내부에 코팅된 관상광촉매 반응기에서 진행된 실험결과 기체의 흐름속도 범위가 0.01~0.25 m/s, CO의 농도가 20~100 ppm 그리고 기체의 상대습도가 20~40%의 범위에서 CO는 UV의 조사 조건에서 거의 100% 정도 제거될 수 있었다. 기체흐름에 포함된 CO의 전환율은 기체의 흐름속도가 증가할수록 그리고 포함된 CO의 농도가 증가할수록 점점 감소하였다. 기체 흐름에 포함된 수분은 OH 라디칼을 형성함으로써 CO의 제거를 촉진할 수 있었다.

• 한국수소및신에너지학회논문집
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• 제26권5호
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• pp.445-452
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• 2015

A tubular packed bed reactor for the steam-$CO_2$ combined reforming of natural gas to produce the synthesis gas of a target $H_2/CO$ ratio 2.0 was simulated. The effects of the reactor dimension, the feed gas composition, and the gas feeding temperature upon the possibility of coke formation across the catalyst bed were investigated. For this purpose, 2-dimensional heterogeneous reactor model was used to determine the local gas concentrations and temperatures over the catalyst bed. The thermodynamic potential distribution of coke formation was determined by comparing the extent of reaction with the equilibrium constant given by the reaction, $CH_4+2CO{\Leftrightarrow}3C+2H_2O$. The simulation showed that catalysts packed in the central region nearer the entrance of the reactor were more prone to coking because of the regional characteristics of lower temperature, lower concentration of $H_2O$, and higher concentration of CO. With the higher feeding temperature, the feed gas composition of the increased $H_2O$ and correspondingly decreased $CO_2$, or the decrease in the reactor diameter, the volume fraction of the catalyst bed subsequent to coking could be diminished. Throughout the simulation, reactor dimension and reaction condition for coking-free operation were suggested.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2009년도 제33회 추계학술대회논문집
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• pp.58-61
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• 2009

추진제로써 아산화질소를 활용하기 위해 아산화질소의 촉매 분해 특성에 대한 연구를 수행하였다. 아산화질소를 분해하기 위해 Ru와 Pt 촉매를 $Al_2O_3$ 지지체에 함침법을 이용하여 담지하였고, 관형 반응기를 사용하여 GHSV와 반응온도에 따른 아산화질소의 전환율을 측정하였다. GHSV는 낮을수록, 반응온도는 높을수록 전환율이 높았고, Ru/$Al_2O_3$ 촉매가 Pt/$Al_2O_3$ 촉매보다 우수한 성능을 보였다.

• Korean Chemical Engineering Research
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• 제45권6호
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• pp.677-679
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• 2007

$SiCl_4$ 증기를 수증기에 의해 처음으로 2단계 가수분해시키는 방식에 의해 200~300 nm 크기의 단분산에 가까운 구형 실리카 분말을 건식으로 제조하였다. 1단계로 회분식 반응기를 사용하여 $150^{\circ}C$ 정도의 저온에서 부분 가수분해에 의해 단분산에 가까운 silicon oxychloride 구형 입자를 형성시킨 후 2단계로 관형반응기를 사용하여 $1,000^{\circ}C$에서 가수분해 반응을 완료시킴으로써 1단계 이후의 입자 형상이 거의 그대로 보존된 실리카 분말을 제조하였다.

• 한국표면공학회지
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• 제16권3호
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• pp.87-97
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• 1983

석출전위가 낮은 금속들을 저농도용액에서 전기분해하여 회수하는 방법에 대해 아연과 카드뮴을 모델로 삼아 채취방법을 연구하였다. Hull cell과 hyperbolic twin cell에서 시험해서 전류밀도와 효율이 낮기 때문에 기존방법으로는 회수속도가 매우 느린 것을 알 수 있었다. 전해 채취조건을 좋게 하기 위해서는 음극의 표면적을 크게 하고 흔들어 주며, 또 전해액을 강제 순환시켜 물질이동이 잘 되도록 해야만 한다. Rotating tubular bed reactor 나 impact rod reactor 같은 전해조를 사용하여 여러 종류의 용액 중의 아연과 카드뮴 전해 채취 실험을 하였다. 특히 카드뮴의 잔류농도를 낮추기 위해서는 전해법과 이온교환법을 같이 사용하는 것이 유용하다. 새로운 방법의 처리비용과 기존방법의 처리비용을 비교하여 보았다.

• 한국수소및신에너지학회논문집
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• 제14권2호
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• pp.105-113
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• 2003

The pyrolysis for production of hydrogen and high quality carbon black from natural gas were studied. The reactivities in tubular reactor and FVR(free volume reactor) for the methane pyrolysis were compared, in order to prevent the formation of undesirable carbon product such as pyrocarbon, the FVR was designed. The hydrogen yield and the formation of carbon black from methane pyrolysis in this reactor were investigated at temperature range between 1443 and 1576K. From the result of TEM (transmission electron microscopy) analysis, it was confirmed that the CFC(catalytic filamentous carbon) was formed without pyrocarbon.

• 상하수도학회지
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• 제23권5호
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• pp.539-545
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• 2009

A feasibility of a pilot scale two-phase anaerobic digestion with ultra filtration system treating garbage leachate were evaluated. The treatment system consisted of a thermophilic acidogenic reactor, a mesophilic methanogenic reactor, and an UF membrane. The average COD removal efficiency of the treatment system was 95% up to the OLR of 3.1 g COD/L/d. The higher COD removal efficiency with membrane unit resulted from the removal of some portion of soluble organics by membrane as well as particulate materials. When the membrane unit was in operation, bulk liquid in acidogenic and methanogenic reactors was partially interchanged, which maintained the acidogenic reactor pH over 5.0 without external chemical addition. Also, with the production of methane in the acidogenic reactor, the organic loading rate of the methanogenic reactor reduced. The initial flux of the membrane unit was $50{\sim}60L/m^2/hr$, but decreased to $5 L/m^2/hr$ after 95 days of operation due to clogging caused by particulate materials such as fibrous materials in garbage leachate. To prevent clogging caused by particulate materials, a pretreatment system such as screening is required. With the improvement with membrane unit operation, the two-phase anaerobic digestion with ultra filtration system is expected to have the possibility of treating garbage leachate.