• Korean Chemical Engineering Research
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• v.47 no.2
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• pp.195-202
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• 2009

As a basic research of developing two-interconnected fluidized beds system for selective solid circulation, a solid separator was developed to separate fine and coarse particles by means of particle size difference with particle size separation system equipped with metal screen. The effects of gas velocity, height of solid separator, and separation area on the solid separation rate were investigated as well. The solid separation rate increased as the gas velocity, height of solid separator, and separation area increased. As the gas velocity and height of the solid separator increased, the variation of the solid separation rate was consistent with that of bubble size. Consequently, coarse($212{\sim}300{\mu}m$) and fine($63{\sim}106{\mu}m$) particles were separated using the solid separator and the solid separation rate was ranged from 4.4 to 127 g/min. We also proposed two interconnenced fluidized beds system for sorption enhanced water-gas shift process equipped with the developed solid separator.

• Korean Chemical Engineering Research
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• v.47 no.3
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• pp.355-361
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• 2009

Effects of operating variables on solid separation rate in two-interconnected fluidized beds system for selective solid circulation have been investigated. Coarse(212~300 or $425{\sim}600{\mu}m$) and fine($63{\sim}106{\mu}m$) particles were separated using the solid separator and the solid separation rate was ranged from 66 to 987 g/min. The solid separation rate increased as the gas velocity through the solid injection nozzle, solid height, diameter of solid injection nozzle, particle size of coarse particles, aperture of the solid separator, and weight fraction of fines in the solid mixture increased. However, the effect of the fluidization velocity was negligible.

• Journal of the Korean Ceramic Society
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• v.38 no.1
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• pp.1-8
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• 2001

선택적 가스분리를 위한 분자체탄소(Molecular Sieve Carbon: MSC)로서의 활용을 위해 제조된 활성탄소섬유의 흡착능과 분자체 특성이 다양한 분자크기를 갖는 가스 흡착실험을 통해 조사되었다. 각 활성화 조건별 세공크기분포와 세공발달 전개과정을 유추함으로서, 세공크기분포의 조절이 가능하게 되었으며 활성탄소섬유의 분자체 탄소로서 활용을 용이하게 할 수 있었다. 800, 85$0^{\circ}C$의 온도로 수증기에 의해 활성화한 활성탄소섬유의 경우 burn-off가 각각 50, 40% 정도를 가진 활성탄소섬유가 비교적 작은 분자크기(0.3~0.4nm)의 흡착질에 대한 분자체 특성을 나타냈다. 또한, 다양한 분자크기의 흡착질을 포함하는 혼합가스의 유속과 흡착온도의 조절로서 원하는 흡착질의 선택적 분리를 위해 활성탄소섬유가 갖는 분자체 특성 향상을 보였다.

• Transactions of the Korean hydrogen and new energy society
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• v.1 no.1
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• pp.15-23
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• 1989

The selective separation of hydrogen from gas mixture containing hydrogen was experimentally studied using $LaNi_5$. The capacity and the rate of hydrogen separation, the purity of recovered hydrogen and the optimum condition of the regeneration of deactivated $LaNi_5$ were investigated. The separation rate and the recovery ratio of hydrogen were slowly decreased with the increase of the number of hydrogen absorption cycle. It was found that this result comes from the deactivation of $LaNi_5$ partly because of the blocking of hydrocarbon compounds in the $LaNi_5$ lattice and partly because of the poisoning of $LaNi_5$ surface by carbon monoxide contained in the gas mixture. The optimum condition for the regeneration of deactivated $LaNi_5$ was obtained by heating in a vacuum to about 637 K. The recovery ratio of hydrogen at the optimum condition was observed to be about 80%. The rates of hydrogen separation were measured in the ${\alpha}$-phase and two phase regions. The rate equations could be expressed as follows ; ${\alpha}$ - phase : $$-\frac{dP{_{H_2}}}{dt}=9.836{\times}10^{-3}(P{_{H_2}}_{-P_{eq}})$$ two phase region : $$-\frac{dP_{H{_2}}}{dt}=1.6909{\times}10^2\exp(-17560/RT)(P{_{H_2}}_{-P_{eq}})$$.

• Korean Chemical Engineering Research
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• v.49 no.6
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• pp.865-868
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• 2011

An organic substance, hydroquinone is used to form clathrate compounds in order to identify separation characteristics of carbon dioxide in flue gas. Formed samples were analyzed by means of the solid-state $^{13}C$ nuclear magnetic resonance (NMR) and Raman spectroscopic methods to examine enclthration behaviors of guest species. In addition, elemnetal analysis was also performed in order to evaluate separation efficiency of $CO_2$ in a quantitative way. Based on the experimental results obtained, $CO_2$ molecules are found to be captured into the clathrate compound more readily than $N_2$ molecules. Moreover, because such preferential enclathration is even more significant at low pressure conditions, $CO_2$ separation/recovery from flue gas can be achieved with minimizing additional energy cost for the technique. Experimental results obtained in this study can provide useful information on separation techniques of flue gas or selective separation of gas mixtures in the future.

• Archives of Pharmacal Research
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• v.24 no.5
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• pp.402-406
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• 2001

Gas chromatographic method was investigated for the chiral separation of several $\beta$-blockeros(atenolol, betaxolol, bisoprolol, metoprolol and pindolol) using (-)-$\alpa$-methoxy-$\alpa$-(trifluoromethyl)phenylacetyl chloride as a chiral derivatizing agent for amino group. Prior to N-acylation, hydroxyl group was converted into O-silyl ethers by react with N-methyl-H-(taimethylsilyl)trifluoroacetamide. The reaction was selective and rapid and the diasteromeric derivatives were well separated by capillary gas chromatography. (R)-isomers were eluted faster than (S)-isomers when (-)-$\alpa$-methoxy-$\alpa$-(trifluoromethyl)phenylacetyl chloride was used as the chiral derivatizing agent. But in the opposite sequence when (+)-$\alpa$-methoxy-$\alpa$-(trifluoromethyl)phenylacetyl chloride was used. No racemization was found during the reaction.

• Korean Chemical Engineering Research
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• v.47 no.3
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• pp.337-343
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• 2009

To apply to novel two-interconnected fluidized beds system for selective solid circulation, a solid separator and a solid circulation system were developed. The solid separation rate increased as the gas velocity through the solid injection nozzle, solid height, and diameter of solid injection nozzle increased. However, the effect of the fluidization velocity was negligible. Coarse($212{\sim}300{\mu}m$) and fine($63{\sim}106{\mu}m$) particles were separated using the solid separator and the solid separation rate was ranged from 66 to 453 g/min. The solid circulation rate increased as the gas velocity through the solid injection nozzle, solid height, and the number of solid intake holes increased. However, the effect of the fluidization velocity was negligible. Fine particle was circulated using the solid circulation system and the solid circulation rate was ranged from 65 to 390 g/min. We also proposed two interconnenced fluidized beds system for selective solid circulation equipped with the developed solid separator and the solid circulation system. Long-term operation of continuous solid circulation up to 20 hours has been performed to check feasibility of stable operation. The pressure drop profiles in two beds and the solid separation rate were maintained steadily, and therefore, we could conclude that solid circulation was smooth and stable.

• New & Renewable Energy
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• v.5 no.4
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• pp.46-51
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• 2009

The purpose of this study is to investigate selective adsorption of $CO_2$ from LFG (Landfill gas) by using commercialized NaX-type zeolite adsorbent under the ambient temperature and pressure. The experiment of $CO_2$ adsorption was carried out by using simulated LFG. The $CO_2$ adsorption capacity and separation efficiency of NaX-type adsorbent were investigated by analyzing gas flow rate and gas composition at inlet and outlet of the adsorption reactor. The adsorbed $CO_2$ were desorbed under decompression condition which 0.5 Torr or by air purge. Through the result to use simulated LFG, when the method of VSA was used, 73.2~75.3 mg of $CO_2$ was adsorbed per 1 g commercial adsorbent, when the method of air purge was used, 78.4~83.2 mg of $CO_2$ was adsorbed per 1 g of commercial adsorbent.

• Membrane Journal
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• v.33 no.3
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• pp.94-109
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• 2023

1,3-Dioxolane is an exciting material that has attracted widespread interest in the chemical, paint, and pharmaceutical industries as a solvent, electrolyte, and reagent because 1,3-dioxolane is not toxic, carcinogenic, explosive, auto-flammable, and multifunctional, and due to their excellent miscibility in most organic and aqueous solvent conditions. Recently, this material has received increasing attention as a CO₂-selective polymer precursor to separating CO₂ from flue gas and natural gas mixtures. Poly(1,3-dioxolane) (PDXL) possesses higher ether oxygen content than polyethylene oxide (PEO), which demonstrates superior membrane CO₂/N₂ separation properties owing to their polar ether oxygen groups exhibiting strong affinity toward CO₂. Thus, PDXL-based membranes displayed an outstanding CO₂ solubility selectivity over non-polar (N₂, H₂, and CH₄) gases. However, the polar groups of PDXL, like PEO, promote chain packing efficiency and cause polymer crystallization, thereby reducing its gas permeability, which should be improved. In this short review, we discuss the recent advancement and limitations of PDXL membranes in gas separation applications. To conclude, we provide future perspectives for inhibiting the limits of 1,3-dioxolane-based polymers in the CO₂ separation process.

• Membrane Journal
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• v.27 no.2
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• pp.167-181
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• 2017

Graphene-based materials have been considered as a promising membrane material, due to its easy processability and atomic thickness. In this study, we studied on gas permeation behavior in few-layered GO membranes prepared by spin-coating method. The GO membrane structures were varied by using different GO flake sizes and GO solutions at various pH levels. The GO membranes prepared small flake size show more permeable and selective gas separation properties than large one due to shortening tortuosity. Also gas transport behaviors of the GO membranes are sensitive to slit width for gas diffusion because the pore size of GO membranes ranged from molecular sieving to Knudsen diffusion area. In particular, due to the narrow pore size of GO membranes and highly $CO_2$-philic properties of GO nanosheets, few-layered GO membranes exhibit ultrafast and $CO_2$ selective character in comparison with other gas molecules, which lead to outstanding $CO_2$ capture properties such as $CO_2/H_2$, $CO_2/CH_4$, and $CO_2/N_2$. This unusual gas transport through multi-layered GO nanosheets can explain a unique transport mechanism followed by an adsorption-facilitated diffusion behavior (i.e., surface diffusion mechanism). These findings provide the great insights for designing $CO_2$-selective membrane materials and the practical guidelines for gas transports through slit-like pores and lamellar structures.