• Clean Technology
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• v.14 no.4
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• pp.275-280
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• 2008

In this study, we carry out economic and technical feasibility study for treatment process of waste solvent such as SD waste solution and stripper solution from LCD manufacturing process. Extensive screening work has been done for selecting the best extraction solvent. As a result, it is shown that $CHCl_3$ is the most adequate extraction solvent for separation and recovery of both SD waste solvent and stripper waste. Rigorous simulation study has been carried out for extraction process and distillation process as a candidate of waste solvent treatment. The result shows that the solvent extraction process is more beneficial than the simple distillation process.

• Korean Chemical Engineering Research
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• v.52 no.3
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• pp.307-313
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• 2014

In this study, an optimization process design has been performed to separate 99.9 mol% of Isobutyl Acetate from binary azeotropic mixture of Isobutyl Acetate and Isobutyl Alcohol system using a Pressure Swing Distillation (PSD). PSD is used to separate binary azeotropic mixtures using the difference between the relative volatilities and azeotropic compositions by changing the system pressure. Non-Random Two Liquid (NRTL) model for liquid phase and the Peng-Robinson equation for vapor phase are used. An optimization study for the reflux ratio and feed stage locations which minimize the total reboiler heat duties are studied. Since PSD process consists of two columns, i.e. high pressure and low pressure, the effect of column sequence on the optimum conditions is reported.

• Korean Chemical Engineering Research
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• v.45 no.1
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• pp.57-66
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• 2007

Natural gases generally consist of mainly $^{12}C$ and about 1.1% of $^{13}C$. It is well known that a stable carbon isotope, $^{13}C$, has been widely used for the applications of medical, pharmaceutical, and agricultural tracers. As a result, the development of the separation and concentrating technology of $^{13}C$ can cause of high value-added products and the possibility of the generation of new carbon materials, In general, there are two kinds of approaches to obtain a stable $^{13}C$ isotope by the separation of cryogenic distillation. One is to obtain a concentrated $^{13}CH_4$ isotope from natural gas. Another approach is to get concentrated $^{13}CO$ by distillation followed by a chemical reaction of $CH_4$ and $H_2O$. In this study, rigorous process simulations of the cryogenic distillation have been performed and analyzed for the concentrated separation of $^{13}C$ isotopes from LNG and NG by using commercial process simulator. Due to the very small differences of relative volatilities and separabilities of $^{12}C$ and $^{13}C$, the process design and operation of effective separation and concentration of $^{13}C$ need special strategies and feasibility studies. Utilization of vapor pressure data to acentric factor in SRK equation of state and optimized process conditions have been able to predict for the effective of the separation yield and concentration of $^{13}C$ for the cryogenic distillation. The various operation strategies for both batch and continuous cryogenic distillation are also studied and suggested for the basic design of the process. Development of this study can provide a tool for the effective design and operation of the cryogenic separation of $^{13}C$.

• Nuclear Engineering and Technology
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• v.28 no.4
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• pp.415-422
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• 1996

Tritium removal from tritiated heavy water in a PHWR is the most effective way in reducing workers' internal dose and radioactivity emissions from Wolsong NPP. The optimum design of the Wolsong TRF (Tritium Removal Facility) was carried out using an approximate short-cut method with an assumption that the TRF, designed to extract 8 MCi per year of elemental tritium from a heavy oater feedstream, uses Liquid Phase Catalytic Exchange (LPCE) front-end process and Cryogenic Distillation (CD) process.

• Korean Chemical Engineering Research
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• v.45 no.1
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• pp.39-45
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• 2007

This paper proposed a shortcut method for the structure design of dividing wall column based on the Fen-ske-Underwood equation by applying it on three conventional simple column configuration. It is shown that the proposed shortcut method can design the column structure including the feed tray, dividing wall section, and side-stream tray in a simple and efficient way in the initial design stage. Simulation study using HYSYS to compare the energy saving performance between the conventional sequential two column system and the dividing wall column designed by the proposed method shows that the proposed dividing wall column system saves from 16% to 65% more over the condepends on the composition of intermediate component while the optimal energy consumption pattern to internal flow distribution on the dividing wall section is characterized by the ESI factor of the feed mixture.

• Transactions of the Korean hydrogen and new energy society
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• v.30 no.1
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• pp.83-94
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• 2019

LPG is increasingly being used as a clean energy source due to the continuous strengthening of environmental regulations. In addition, the demand of propane which is the basic compound for petrochemicals is increasing for propylene production. In the study, a divided wall column was used as de-propanizer and de-butanizer, which is expected to save large amount of energy among the four conventional distillation columns used for processing LPG. The simulation results showed a decrease of energy duty with ESI by 30.30% using two divided wall columns. Furthermore, simulation case studies were carried out with respect to design and operation condition. The main column tray and withdrawal tray were determined from the design case studies while the internal liquid flow and vapor flow were decided from the operating case studies. Also, ESI of 1.06% could be achieved from the case studies. According to the results, the simulation method used showed that it is greatly helpful to the design and evaluate a highly efficient divided wall column.

• Nuclear Engineering and Technology
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• v.18 no.2
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• pp.107-116
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• 1986

The steady and unsteady state models were established for the performance analysis and design of heavy water distillation columns packed with corrugated wire mesh. After the steady state model was derived with pressure drops, separated D$_2$O concentration and temperature profiles and pressure gradients in the column were obtained by solving MESH equations with equation tearing method. For the analysis of unsteady state behavior, the equilibrium stage transient model deduced from modifying the Cohen's ideal cascade equation was used to predict the concentration change of heavy water with time. These models were in good agreement with the experimental results of heavy water distillation at total reflux. And the newly developed packing material turned out to be very efficient separation device for very small HETP, pressure drop and holdup.

• Korean Journal of Chemical Engineering
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• v.35 no.11
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• pp.2241-2255
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• 2018

RSM methodology was applied to present mathematical models for the fabrication of polyvinylidene fluoride (PVDF) dual-layer hollow fibers in membrane distillation process. The design of experiments was used to investigate three main parameters in terms of polymer concentration in both outer and inner layers and the flow rate of dope solutions by the Box-Behnken method. According to obtained results, the optimization was done to present the proper membrane with desirable properties. The characteristics of the optimized membrane (named HF-O) suggested by the Box-Behnken (at the predicted point) showed that the proposed models are strongly valid. Then, a morphology study was done to modify the fiber by a combination of three types of a structure such as macro-void, sponge-like and sharp finger-like. It also improved the hydrophobicity of outer surface from 87 to $113^{\circ}$ and the mean pore size of the inner surface from 108.12 to 560.14 nm. The DCMD flux of modified fiber (named HF-M) enhanced 62% more than HF-O when it was fabricated by considering both of RSM and morphology study results. Finally, HF-M was conducted for long-term desalination process up to 100 hr and showed stable flux and wetting resistance during the test. These stepwise approaches are proposed to easily predict the main properties of PVDF dual-layer hollow fibers by valid models and to effectively modify its structure.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10a
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• pp.376-379
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• 1996

Synthesis for qualitative analysis in connection with quantitative analysis from the pinch design method, EVOP and Operations Research is proposed for the optimal synthesis of heat exchanger networks, that is through of the transportation model of the linear programming for synthesizing chemical processing systems, to determine the location of pinch points, the stream matches and the corresponding heat flowrate exchanged at each match. In the second place, according to the optimization, the optimal design of heat transfer enhancement is carried on a fixed optimum heat exchanger network structure, in which this design determines optimal operational parameters and the chosen type of heat exchangers as well. Finally, the method of this paper is applied to the study of the optimal synthetic design of heat exchanger network of constant-decompress distillation plants.

• Korean Chemical Engineering Research
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• v.59 no.3
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• pp.467-479
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• 2021

Abstract: A kinetic model was developed for the dehydration of ethanol to ethylene based on two parallel reaction pathways. Kinetic parameters were estimated by fitting experimental data of powder catalysts in a lab-scale test, and the effectiveness factor was determined using data from pellet-type catalysts in bench-scale experiments. The developed model was used to design a multitubular fixed-bed reactor (MTR) and an adiabatic reactor (AR) at a 10 ton per day scale. The two different reactor types resulted in different process configurations: the MTR consumed the ethanol completely and did not produce the reaction intermediate, diethyl ether (DEE), resulting in simple separation trains at the expense of high equipment cost for the reactor, whereas the AR required azeotropic distillation and cryogenic distillation to recycle the unreacted ethanol and to separate the undesired DEE, respectively. Quantitative analysis based on the equipment and annual energy costs showed that, despite high equipment cost of the reactor, the MTR process had the advantages of high productivity and simple separation trains, whereas the use of additional separation trains in the AR process increased both the total equipment cost and the annual energy cost per unit production rate.