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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Korean Chemical Engineering Research
Journal Basic Information
Journal DOI :
The Korean Institute of Chemical Engineers
Editor in Chief :
KIM JAE JEONG
Volume & Issues
Volume 31, Issue 6 - Dec 1993
Volume 31, Issue 5 - Oct 1993
Volume 31, Issue 4 - Aug 1993
Volume 31, Issue 3 - Jun 1993
Volume 31, Issue 2 - Apr 1993
Volume 31, Issue 1 - Feb 1993
Selecting the target year
A Study on the Property changes According to Surface States of Substrate in the Preparation of Y-Ba-Cu-O
Superconducting Thin Films by Chemical Vapor Deposition
Shin, Hyung-Shik ; Cho, Ik-Joon ; Park, Joung-Shik ; Yang, Seog-Woo ; Lee, Hee-Gyeun ; Won, Dong-Yeon ;
Korean Chemical Engineering Research, volume 31, issue 2, 1993, Pages 131~131
Since the discovery of superconducting oxides, enormous amount of research has been conducted on the preparation of
superconducting films. It is obvious that future microelectronic devices will require well-crystallized films of smooth surface and uniform structure prepared at substrate temperatures as low as possible. The
superconducting Y-Ba-Cu-O thin films in this work were prepared by thermal chemical vapor deposition method on MgO(100) substrate without postannealing using
metal chelates of
as source materials and
as a reactant gas. Superconductivity above liquid nitrogen temperature
was obtained for the film prepared at
and 0.0126torr. The thin films consisted of Y-Ba-Cu-O with mostly c-axis perpendicular to the substrate plane and with small amounts of a-axis normal to film surface.
The Effect of Substrate Feeding Variation on the SBR Process
Park, Dong-Keun ; Lee, Min-Gyu ; An, Kab-Hwan ; Song, Seung-Koo ;
Korean Chemical Engineering Research, volume 31, issue 2, 1993, Pages 137~137
A laboratory scale sequencing batch reactor with a total cycle period of 24 hours was operated to investigate its performance to artificial sewage whose composition was similiar to that of actual municipal sewage. More than 97% of inlet COD was removed at a SRT of 13 days and organic loading rate of 0.38kg
. The observed yield was shown in the range of 0.75 to 0.44 with the change of the substrate feeding interval of 1 minute through 12 hours. With these experimental conditions, the removal efficiency of nitrogen was ranged from 74 to 83%, which was much higher than that of the ordinary activated sludge process. It was found that the nitrogen removal was well increased with intermittent substrate feeding under no aeration and the observed yield and the removal efficiency of phosphorous were also increased according to the decrease of the substrate feeding interval.
Permeate Flux Improvement Using Turbulence Promoter in Ultrafiltration
Park, Ham-Yong ; Oh, Joon-Taek ; Lim, Gio-Bin ; Kim, Woo-Sik ;
Korean Chemical Engineering Research, volume 31, issue 2, 1993, Pages 144~144
A channel spacer of spiral-wound membrane module was applied to a flat plate ultrafiltration cell as a turbulence promoter in order to reduce concentration polarization in ultrafiltration of dextran(M.W. 500,000) solution. As a result of using turbulence promoter the permeate flux was improved by 13.8-114.4% depending on membranes and operational conditions. Mass transfer correlation was modified by considering variation of physical properties(viscosity, density and diffusivity) in concentration polarization layer. The modified mass transfer correlation showed better agreement with experimental results than the conventional one. The modified mass transfer correlation is as follow:
Isothermal Vapor-Liquid Equilibria of
Kim, Chul-Ung ; Koh, Jae-Cheon ; Lee, Jung-Min ;
Korean Chemical Engineering Research, volume 31, issue 2, 1993, Pages 154~154
Isothermal vapor-liquid equilibria have been determined for
using headspace gas chromatography as static method. The system
forms an azeotropic mixture, while the other two systems did not have the azeotrope. The obtained results were correlated to the Wilson, Van Larr, Margules, NRTL equations. These experimental vapor-liquid equilibrium data for binary systems of methychlorosilanes are presented as the basic data of separation process.
Separation of Benzene-Cyclohexane Mixtures by Nonadiabatic Column Crystallizer
Kim, Kwang-Joo ; Lee, Choul-Ho ; Koh, Jae-Cheon ;
Korean Chemical Engineering Research, volume 31, issue 2, 1993, Pages 160~160
The eutectic mixture of benzene-cyclohexane was separated by the nonadiabatic column crystallization process of bench scale. Experimental determinations were made of temperature and concentration profiles established during the purification of benzene with cyclohexane as impurity under steady state, batch conditions of operation. The comparison of the performance of purification in the nonadiabatic column crystallizer with that in the adiabatic column crystallizer, phenomena of the freezing zone and the effect of initial concentration were discussed. The back mixing of the purification zone in the nonadiabatic column crystallizer was a twentieth times of that in adiabatic column crystallizer. Benzene containing below 100ppm cyclohexane was obtained by processing feed material with 30000 to 70000ppm cyclohexane.
A Study of Cavities Formed behind the Impeller Blades in a Gas-Liquid Agitated Reactor
Huh, Yun-Jun ; Choi, Cheong-Song ; Lee, Won-Hong ;
Korean Chemical Engineering Research, volume 31, issue 2, 1993, Pages 169~169
The transition conditions between flooding and loading were easily found using a miniature hydro-phone which detects the pressure differences in radial outflow between flooding and loading. The reliability of a proposed method was confirmed by comparing the data with an early published correlation equation. The mass transfer coefficients and the power consumptions of impeller depended on the cavity structures formed behind the impeller blades. From the spectrum analysis of pressure fluctuation, it was realised that the degree of progress of 3-3 structured cavity varied with the change of operating conditions in the 3-3structured cavity region. In view of gas-liquid mass transfer and power consumptions, the optimal operating condition in an agitated reactor could be found by the spectrum analysis of the pressure fluctuations.
Mass Transfer with Intraparticle Forced-Convection in the Packed Column of Porous Particles
Ahn, Dae-Young ; Kwak, Chul ; Park, In-Soo ;
Korean Chemical Engineering Research, volume 31, issue 2, 1993, Pages 178~178
The stimulus-response experiments of non-adsorbing gas were carried out in a packed column of large-pore particles in the region of 1
Separation of Acetylene from Paraffins Using CuCl Complex Reaction
Kim, Dong-Min ; Chang, Ho-Nam ; Song, Kyu-Min ; Hong, Won-Hi ;
Korean Chemical Engineering Research, volume 31, issue 2, 1993, Pages 184~184
The separation of acetylene from paraffins using CuCl complex reaction was investigated. The amount of complexed acetylene increased at lower temperature, in better mixing conditions, with the higher amounts of CuCl present in the slurry and at higher dissociation temperatures, but decreased at higher complexing temperature and repeated use of slurry. If CuCl is not present or the temperature is not suitable for the complexing reaction, only absorption or physical adsorption of gases can occur.
The Production of Rutile Substitute from Titaniferrous Magnetite by the Carbothermal Reduction
Lee, Chul-Tae ; Kim, Eui-Sung ; Lee, Sang-Soon ;
Korean Chemical Engineering Research, volume 31, issue 2, 1993, Pages 193~193
Carbothermal reduction of titaniferrous magnetite with carbon was experimentally investigated in order to get fundamental data for the production of rutile substitute from domestic titaniferrous magnetite ore. The proper condition for the reduction of titaniferrous magnetite was as follows : reaction temperature was
, equivalent ratio of carbon to titaniferrous magnetite was 9.0 and reaction time was 60min. Activated carbon, pitch and charcoal acted as good reducing agent in this reduction. The addition of ferric chloride to titaniferrous magnetite and carbon increased the rate of reduction of titaniferrous magnetite significantly. Reduction rate data under isothermal condition from
were fitted to different rate equations and have been found to be well represented by the equation
, which is developed assuming diffusion of reactants through the product layer is the controlling step. Under above mentioned conditions, all Fe-oxide in the titaniferrous magnetite was reduced to metal Fe. Rutile substitute was prepared from this reduced titaniferrous magnetite by magnetite separation.
The Effect of Prandtl Number on Heat and Mass Transfer in Centrifugal Molecular Still by Numerical Simulation
Park, Dong-Myung ; Song, Kyu-Min ; Hong, Won-Hi ; Yang, Seung-Man ; Yamada, Ikuho ;
Korean Chemical Engineering Research, volume 31, issue 2, 1993, Pages 204~204
The rigorous mathematical model of heat and mass transfer on the rotating surface in the centrifugal molecular distillation is developed. Tangential velocity component to the conical surface is independent of z-direction but not negligible. The solutions of fluid temperature profile and mass transfer rates of distillate are obtained using Finite difference Method. The heat conduction from heating plate to film decreased as Prandtl number increased. These solutions show good agreement with the approximate solution for liquids near
. However these solutions differ from the approximate solutions at Pr>100 as heating rate increases. The solutions in the limited case that the heating rate is equal to the latent heat of vaporization agree with those of Greenberg.
Continuous Process Development of Amion Acid Concentration by Liquid Emulsion Membrane Technique with a Cationic Extractant
Hong, Seong-Ahn ; Choi, Hyung-Joon ; Nam, Suk-Woo ;
Korean Chemical Engineering Research, volume 31, issue 2, 1993, Pages 212~212
A continuous process of amino acid concentration by liquid emulsion membrane with a cationic extractant, D2EHPA, was developed and optimized with respect to the yield of amino acid, the degree of concentration, and membrane stability. Liquid emulsion membrane obtained from the demulsification of the emulsion could be reused without any problem. It was possible to concentrate the fermentation broth of initial concentration of 3.6% up to 17%. A simple and continuous process was proposed to reduce the amino acid concentration of fermentation broth down to 0.15%.
Phase Holdup and Axial Mixing Characteristics of Liquid Phase in a Slurry Bubble Column with a Single Nozzle
Kim, Tae-Ok ; Cho, Ji-Hoon ;
Korean Chemical Engineering Research, volume 31, issue 2, 1993, Pages 222~222
Phase holdup and axial mixing characteristics of liquid phase were investigated in a slurry bubble column with a single nozzle as a gas distributor. In air-water-sand system, gas and liquid velocities ranged from 0.962 to 15.312cm/sec and 0 to
. Experimental results showed that gas holdup in slurry system was larger than that in air-water system, and it was not influenced by slurry velocity and solid concentration. Also, estimated terminal velocity of a bubble based on gas holdup data by using bubble rising velocity was lower than that in the two phase system with perforated plate. by contrast, liquid holdup decreased with increasing gas velocity and solid concentration, and it was not influenced by slurry velocity. At higher gas velocity(about 4cm/sec), axial dispersion coefficient of liquid phase in the slurry system was lower than that in the air-water system and it was larger than that for using perforated plate. In this conditions, estimated axial dispersion coefficient of liquid phase could be expressed as follows.
The Effect of Cosolvent on Desorption of Wool Grease with Supercritical Fluid
Koo, Bon-Sik ; Seo, Jeong-Tae ; Bae, Hyo-Kwang ;
Korean Chemical Engineering Research, volume 31, issue 2, 1993, Pages 229~229
We have studied experimentally and theoretically the desorption characteristics of wool grease on the wool with supercritical carbon dioxide, containing 0.6-4.4mole% of cosolvent, at the pressures up to 35MPa, the temperature of 313.2K, 323.2K and 333.2K and constant flow rate of solvent. Desorption rates of wool grease are found to increase with the concentration increase of cosolvent, to decrease generally with the temperature increase and to increase markedly with increasing pressure. The final desorption amounts are nearly constant at a specified condition. Benzene is proved to be a better cosolvent than n-hexane or methylacetate of the same concentrations in above desorption experiments. The desorption rate constants in the model,
is nearly constant at constant pressure and concentration of cosolvent,
increases with the increase of desorption amount. HPLC chromatograms of the wool grease desorbed show that compositions of the desorpted wool grease are varied with various desorption conditions.
Variation in the Surface and the Gasification Properties of Coal Chars with Pyrolysis Rates
Park, Nam-Soo ; Moon, Sang-Heup ; Lee, Ho-In ; Lee, Wha-Young ; Lee, Hyun-Ku ;
Korean Chemical Engineering Research, volume 31, issue 2, 1993, Pages 235~235
Indonesian lignite and Chinese bituminous coal were pyrolyzed under different heating rates be-tween
, and the chars obtained thereby were steam-gasified in a fixed-bed micro-reactor at temperatures between 800 and
and under the steam partial pressures between 0.26 and 0.57 atmospheres. The chars obtained by fast pyrolysis at the heating rate of
exhibited higher gasification rates than the chars pyrolyzed at the heating rates lower than
, but the apparent activation energies of gasification of the two samples were almost same : 114 KJ/mol and 113 KJ/mol. The char surface areas estimated by gas adsorption exhibited opposite results depending on the adsorption gas,
. The surface areas estimated from
adsorption were higher for the fast-pyfrolyzed chars than for the slowly-pyrolyzed ones. Formation of many micropores in the fast-pyrolyzed chars, evident from transient pressure change in the adsorption experiment, was responsible for 77the relatively high gasification rates.
A Study on the Catalytic Activity of Raney Ni Doped with Transition Metals
Cho, Jeong-Yoon ; Kim, Yeon-Ho ; Kim, Hyung-Jin ;
Korean Chemical Engineering Research, volume 31, issue 2, 1993, Pages 244~244
Doping effect of transition metals in Raney Ni catalyst was investigated by measuring of benzene hydrogenation activity and hydrogen content stored inside the catalyst. The catalyst doped with Ti showed the best catalytic activity of all among the used dopants, and the optimum Ti content in a starting alloy was 1.5wt%, and for the electrochemical reaction it was 2.0wt%. Surface analysis by means of EDS revealed that most of doped Ti was concentrated on the surface of catalyst. The Al leaching mechanism from Raney alloy was selective dissolution. The catalytic activity of Raney Ni was affected considerably by hydrogen pretreatment temperature, and the adequate PTFE content for dispersing catalyst particles was 5wt%.