• 한국응용과학기술학회지
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• 제25권4호
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• pp.469-476
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• 2008

The synthesis of cyclic carbonate from butyl glycidyl ether (BGE) and carbon dioxide was performed in the presence of three different types of ionic liquid : quarternary ammonium salt, alkyl pyridinium salt, and alkylimidazolium salt. Ionic liquids of different alkyl groups ($C_3$, $C_4$, $C_6$ and $C_8$) and anions ($Cl^-$, $Br^-$ and $I^-$) were used for the reaction which was carried out in a batch autoclave reactor at $60{\sim}120^{\circ}C$. The catalytic activity was increased with increasing alkyl chain length in the order of $C_3$ < $C_4$ < $C_6$. But the ionic liquid with longer alkyl chain length ($C_8$) decreased the conversion of BGE because it is too bulky to form an intermediate with BGE. For the counter anion of the ionic liquid catalysts, the BGE conversion decreased in the order $Cl^-$ > $Br^-$ > $I^-$.

• Korea-Australia Rheology Journal
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• 제20권1호
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• pp.1-6
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• 2008

Absorption rate of carbon dioxide was measured in the aqueous xanthan gum (XG) solution in the range of 0-0.15 wt% containing 2-amino-2-methyl-1-propanol (AMP) of $0-2\;kmol/m^3$ in a flat-stirred vessel with an impeller of 0.05m and agitation speed of 50rpm at $25^{\circ}C$ and 0.101 MPa. The volumetric liquid-side mass transfer coefficient ($k_La$) of $CO_2$, which was correlated with the viscosity and the elastic behavior of XG solution containing Deborah number as an empirical formula, was used to estimate the chemical absorption rate of $CO_2\;(R_A)$. $R_A$, which was estimated by mass transfer mechanism based on the film theory using the physicochemical properties and the kinetics of reaction between $CO_2$ and AMP, was compared with the measured rate. The aqueous XG solution with elastic property of non-Newtonian liquid made $R_A$ increased compared with Newtonian liquid based on the same viscosity of the solution.

• 설비공학논문집
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• 제24권5호
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• pp.401-408
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• 2012

Volumetric mass transfer coefficient was measured with carbon dioxide and deionized water for the gas-liquid cocurrent slug flow in 2, 5 and 8 mm tubes. Measurement was repeated with and without a vertical section in an experimental setup and entrance effect was found greater for smaller tubes. Volumetric mass transfer coefficient in the vertical section was found generally a strong function of gas- and liquid-phase superficial velocities. 5 mm- and 8 mm-tube data are highly consistent each other but not with 2 mm tube.

• Korea-Australia Rheology Journal
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• 제18권3호
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• pp.133-141
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• 2006

Carbon dioxide was absorbed into the aqueous nanometer sized colloidal silica solution of 0-31 wt% and 2-amino-2-methyl-1-propanol of $0-2kmol/m^3$ in a flat-stirred vessel with the impeller of various sizes and speeds at $25^{\circ}C$ and 0.101 MPa to measure the absorption rate of $CO_2$. The volumetric liquid-side mass transfer coefficient$(k_La)\;of\;CO_2$ was used to obtain the empirical correlation formula containing the rheological behavior of the aqueous colloidal silica solution. Reduction of the measured $k_La$ was explained by the viscoelastic properties of the aqueous colloidal silica solution. The theoretical value of the absorption rate of $CO_2$ was estimated from the model based on the film theory accompanied by chemical reaction and compared with the measured value.

• 청정기술
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• 제18권2호
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• pp.221-225
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• 2012

본 연구에서는 용매 흡수법을 이용한 이산화탄소 포집공정에 액상 용매의 상전이 현상을 적용하여 온실가스의 재생에너지를 획기적으로 낮출 수 있는 공정에 대한 전산모사를 수행하였다. MEA 30 wt% 수용액에 온실가스인 이산화탄소를 용해시키면 이산화탄소의 mole loading 정도에 따라 두 상으로 상분리가 일어나는데 이 현상을 적용하면 본래의 흡수탑-탈거탑으로 구성된 공정에서보다 재생에너지를 약 61% 가량을 낮출 수 있다.

• Korea-Australia Rheology Journal
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• 제16권1호
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• pp.35-45
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• 2004

Rates of chemical absorption of $CO_2$ in water-in-oil (w/o) emulsion were measured in a flat-stirred vessel at $25^{\circ}C$. The w/o emulsion was composed of aqueous monoethanolamine (MEA) droplets as a dispersed phase and non-Newtonian viscoelastic benzene solutions of polybutene (PB) and polyisobutylene (PIB) as a continuous phase. The liquid-side-mass transfer coefficient ($k_L$) was obtained from the dimensionless empirical equation containing Deborah number expressed as the properties of pseudoplasticity of the non-Newtonian liquid. $k_L$ was used to estimate the enhancement factor due to chemical reaction between $CO_2$ and MEA in the aqueous phase. PIB with elastic property of non-Newtonian liquid made the rate of chemical absorption of $CO_2$ accelerate compared with Newtonian liquid.

• 한국지반환경공학회 논문집
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• 제24권6호
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• pp.5-11
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• 2023

석탄 및 석유와 같은 전통적인 화석 연료는 연소 시 발생하는 열을 통해 에너지를 공급한다. 이러한 과정에서 대기 중에 이산화탄소를 배출하고 지구 온난화를 유발한다. 이산화탄소 저감을 위해 많은 연구들이 수행되고 있다. 이러한 방안 중 하나로, 이산화탄소 지중 저장 기술이 관심을 받고 있다. 이산화탄소 지중 저장은 플랜트 등에서 발생하는 이산화탄소를 포집하여 덮개암 하부 포화지반층에 이산화탄소를 주입하여 저장하는 방법을 일컫는다. 하지만, 제한된 공간에 더 많은 양의 이산화탄소 저장을 위해서는 저장 효율의 향상이 필요하다. 따라서, 본 연구에서는 계면활성제를 활용하여 이산화탄소 지중 저장의 효율을 향상하고자 한다. 또한, 지중저장소의 위치에 따라 압력 및 온도가 상이하기 때문에 이산화탄소는 기체, 액체 및 초임계 상태로 존재가능하다. 따라서, 이산화탄소 상태에 따른 저장 효율 특성을 평가하였다. 그 결과, 주입속도 및 계면활성제의 활용은 저장 효율의 향상을 기대할 수 있고, 그 효과는 기체, 액체 및 초임계 상태 이산화탄소에 발휘되는 것을 확인하였다.

• 한국수소및신에너지학회논문집
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• 제26권6호
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• pp.581-589
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• 2015

In this study, the viscosity of a liquid carbon dioxide ($LCO_2$) that can potentially be used in a wet feed coal gasifier was evaluated. A pressurized capillary viscometer was employed to obtain the viscosity data of $LCO_2$ using two different methods. During the first method, the measurements were conducted under quasi-steady and high pressure flow conditions where two-phase flow was greatly minimized. The viscosity of $LCO_2$ was determined using turbulent friction relationship. At the second flow condition where unsteady flow is induced, the viscosity of $LCO_2$ was measured using the half-time pressure decay data and was further compared with values calculated by the first method.

• 청정기술
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• 제14권4호
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• pp.281-286
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• 2008

Polyacrylamide (PAA) 수용액의 유변학적 특성이 $CO_2$의 흡수속도에 미치는 영향을 고찰하기 위해 $25^{\circ}C$, 1기압에서 평판조의 흡수기(교반조의 임펠러 크기 0.05 m, 교반속도 50 rpm)를 사용하여 PAA 수용액에 $CO_2$의 흡수실험을 행하였다. 제시한 Deborah수와 $CO_2$의 물질전달계수와의 상관관계식으로부터 물질전달계수를 구하여 triethanolamine을 첨가한 PAA수용액에서 $CO_2$의 화학흡수속도의 산출에 사용하였다. PAA수용액에서 $CO_2$의 흡수속도는 동일점도의 기준에서 뉴튼액체에서의 값보다 감소하였다.

• 한국포장학회지
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• 제25권2호
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• pp.31-35
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• 2019

Kimchi is a refreshing sour food which gives sour and carbonic acid taste of carbon dioxide produced during the fermentation process. So, carbon dioxide injection was tried to raise carbonic acid taste of kimchi stored in the airtight container. First, carbon dioxide injection times of a given gas supply system were determined experimentally to attain initial concentration of 80% for different solid/liquid ratios. Since carbon dioxide is dissolved in kimchi to decrease its concentration during storage, periodical carbon dioxide injection conditions were needed and determined to keep the $CO_2$ concentration above 70%. For the initial flushing to 80% $CO_2$ concentration in model system filled with water, the injection time ranged from 40 to 89 seconds for free volumes of 2-8 L. $CO_2$ injection conditions for the under-ripened storage at $10^{\circ}C$ consisted of longer time at more frequent cycles for watery kimchi than for Chinese cabbage kimchi. At $0^{\circ}C$ of subsequent ripened stage storage of watery kimchi, the periodical injection at 3 hour interval was required because of continuous dissolution of carbon dioxide. However, Chinese cabbage kimchi did not require subsequent $CO_2$ injection during the ripened state storage and needed only flushing to 80% $CO_2$ at time of the container opening and closing. These results can be used as basic information for the programmed control of $CO_2$ injection in the kimchi container system.