• 한국재료학회지
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• 제16권9호
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• pp.533-537
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• 2006

The effects of binary solvent mixtures with various ratios of toluene and ethanol on the properties of slurries and green sheets were investigated. Viscosity of slurry was changed by varying the ratio of solvent mixture which affected the solubility of binder. The relative solvency behavior of a solvent mixture could be predicted with the Hildebrand solubility parameter(${\delta}$) and hydrogen bonding index( ${\gamma}$). The minimum viscosity, the best dispersion of binder, was reached at the composition of toluene:ethanol=4:6, which corresponded to our forecast. The mechanical properties of green sheets related to evaporation of solvents were influenced by the composition of the solvent mixture. At the azeotrope the skin was formed on a drying cast during the drying process because of fast evaporation. At a range of concentrations over 50wt% toluene, green sheets could not be fully dried at low temperature due to excessive toluene. The mechanical properties of green sheets were excellent at the azeotrope-like composition of toluene:ethanol=4:6 which has a little excess of toluene over the azeotrope.

• 한국수소및신에너지학회논문집
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• 제17권2호
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• pp.212-217
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• 2006

An experimental study on Electro-electrodialysis (EED) for IS (Iodine-Sulfur) process which is well known as hydrogen production system was carried out for the HI concentration from HIx (HI: $H_2O$ : $I_2$ = 1 : 5 : 1) solution. The polymer electrolyte membrane and the activated carbon cloth were adopted as a cation exchange membrane and electrode, respectively. In order to evaluate the temperature effect about HI concentration in fixed molar ratio, three case of temperature were selected to $60^{\circ}C$, $90^{\circ}C$ and $120^{\circ}C$. The electro-osmosis coefficient and transport number of proton have been changed from 1.95 to 1.21 (mol/Faraday) and 0.91 to 0.76, respectively as temperature increase from $60^{\circ}C$ to $120^{\circ}C$. It can be realized that the HI mole fraction in final stage of EED experiments already over the quasi-azeotrope composition.

• 한국수소및신에너지학회논문집
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• 제18권4호
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• pp.458-463
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• 2007

An experimental study on scale-up of Electro-electrodialysis(EED) to increase the efficiency of HI decomposition section in the IS(Iodine-Sulfur) process was carried out. The EED stack extends the effective area of the membrane to 20 times of that formerly used in a single EED unit cell. The experiment was carried out using HIx solution($HI:H_2O:I_2=1:8.4{\sim}9:1.85{\sim}1.9$) at $100^{\circ}C$ and various solution flow rates of 20, 30, 40 and 50 cc/min. The increased HI molality in catholyte after one-pass throughout from the EED stack was 3 mol/kg-$H_2O$, 2.2 mol/kg-$H_2O$, 2 mol/kg-$H_2O$ and 1.37 mol/kg-$H_2O$ at 20, 30, 40 and 50 cc/min, respectively. These values satisfied the target of HI molality(the increase of HI molality: 2 mol/kg-$H_2O$) in the IS process for hydrogen production of 20 L/hr.

• 공업화학
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• 제19권5호
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• pp.539-546
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• 2008

Acetone/methanol 공비혼합계에 대하여 제3성분 entrainer로서 water, aniline, 1,3-diethylbenzene, furfural 및 MEK를 첨가하였을 때의 entrainer효과에 의한 기-액평형 곡선 및 비휘발도와의 관계를 이용하여 최적 entrainer를 선정하였다. water를 entrainer로서 사용했을 경우에는 기-액평형 실험치와 modified-UNIFAC을 이용한 계산치를 비교 검토하여 보았을 때, water의 액조성이 0.3에서부터 0.7까지 공비점이 없는 분리가 가능한 기-액평형 곡선을 얻을 수 있었다. aniline과 1,3-diethylbenzene의 경우에는 액조성을 0.7 이상으로 주입하였을 경우 공비점 없이 분리는 되지만 추출증류의 entrainer로 사용하기는 어렵다는 것을 알 수 있었다. 또한 furfural과 MEK의 경우에는 공비점이 있으므로 추출증류에 이용할 수 없다는 사실을 알 수 있었다. water의 비휘발도는 1.0보다 크고 또한 액조성에 따라 비휘발도가 비선형적으로 증가하는 것으로 나타났으나, water 이외의 다른 제3성분에 대해서는 액조성이 증가함에 따라 모두 비휘발도가 비선형적으로 감소하는 것으로 나타났다. 연구의 결과로서 acetone/methanol 공비혼합계에 대해서는 water가 가장 효율적이며 경제적인 최적 entrainer로 적용될 수 있음을 알 수 있었다.

• 한국산학기술학회논문지
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• 제13권8호
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• pp.3764-3773
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• 2012

본 연구에서는 methyl ethyl ketone (MEK)와 물의 이성분계 공비 혼합물의 공비조성이 압력에 따라서 민감하게 변하는 현상을 이용하여 압력변환 증류(pressure-swing distillation; PSD)공정을 통해서 순도가 99.9mole% 이상의 MEK를 분리해 내기 위한 전산모사 및 공정 최적화를 수행하였다. 전산모사를 위하여 상용성 화학공정 모사기인 Invensys사의 PRO/II with PROVISION 9.1을 활용하였고, 열역학 모델식으로는 Wilson 액체 활동도계수 모델식을 활용하였다. PSD 공정은 저압 및 고압의 증류탑 2기의 증류탑 배열을 사용하는데 저압 증류탑을 전단에 두는 저압-고압 증류탑 배열과 저압 증류탑을 후단에 두는 고압-저압 증류탑 배열로 분류할 수 있다. 본 연구에서는 각각의 배열에 대한 증류탑 환류비와 원료 주입단의 위치를 조절변수로 하여 총 재비기의 heat duty의 합을 최소화시킨 후 두 공정배열을 서로 비교하였다.

• Korean Journal of Chemical Engineering
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• 제35권12호
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• pp.2336-2347
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• 2018

The azeotrope of methyl acetate methanol and water was isolated using extractive distillation with water as entrainer. The pressure-swing extractive distillation (PSED) process and vapor side-stream distillation column (VSDC) with the rectifier process were designed to separate the methyl acetate, methanol and water mixture. It was revealed that the VSDC with the rectifier process had a reduction in energy consumption than the PSED process. Four control schemes of the two process were investigated: Double temperature control scheme (CS1), $Q_R/F$ feedforward control of reboiler duty scheme for PESD (CS2), $Q_R/F$ feedback control scheme for VSDC (CS3), the feedback control scheme of sensitive plate temperature of side-drawing distillation column to dominate the compressor shaft speed (CS4). Feed flow and composition disturbance were used to evaluate the dynamic performance. As a result, CS4 is a preferable choice for separation of methyl acetate-methanol-water mixture. A control scheme combining the operating parameters of dynamic equipment with the control indicators of static equipment was proposed in this paper. It means using the sensitive plate temperature of side-drawing column to control the compressor shaft speed. This is a new control scheme for extractive distillation.