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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 :
Volume & Issues
Volume 28, Issue 6 - Dec 1990
Volume 28, Issue 5 - Oct 1990
Volume 28, Issue 4 - Aug 1990
Volume 28, Issue 3 - Jun 1990
Volume 28, Issue 2 - Apr 1990
Volume 28, Issue 1 - Feb 1990
Selecting the target year
On the Axial Mixing Characteristics of Circulating Slurry-Suspension in the Three Phase Slurry Bubble Column with a Draft Tube
Park, Chan-Jin ; Oh, Kwang-Jung ; Doh, Dong-Seop ;
Korean Chemical Engineering Research, volume 28, issue 5, 1990, Pages 493~493
Axial mixing characteristics in the circulating slurry suspension by bubble-agitation in a bubble column with a draft tube were studied in a 8.90cm
high acryl column. Axial dispersion coefficient increased with the rise of superficial gas velocity and the concentration of particles and was larger than that without the addition of particles. But tendency with the change of paricle size was not clear. To explain these phenomena, the energy dissipation rate estimated from the energy balance was combined with Kolmogoroff’s isotropic turbulence theory to predict the theoretical axial dispersion coefficient. This theoretical equation could explain the tendency of the experimental data of axial dispersion coefficient very well.
Leaching of Nickel Ion from Heazlewoodite by Ferric Ion
Lee, Hak-Sung ; Kim, Young-Tae ; Kim, Hong-Kyung ;
Korean Chemical Engineering Research, volume 28, issue 5, 1990, Pages 499~499
In leaching of heazlewoodite obtained by pretreatment of nickel matte, the effects of temperature and oxidant concentration on leaching rate of nickel were investigated and kinetic parameters for selected optimum model of leaching mechanism were calculated. Fixed amount of heazlewoodite, contained
of particle diameter, was compressed to pellet shape and leached in a mixture of
and HCl as oxidant. The leaching rate was faster at higher temperature but activation energy for initial reaction was as low as 8kcal/mol, which indicates its low dependence on temperature. Stirring speed and ionic concentration of
had no significant effects on the rate and that of
had effect on initial rate only. The rate controlling step for nickel dissolution was judged to be the diffusion of nickel through the layer of NiS, reaction intermediate.
from the Alunite
Lee, Chel-Tae ; Kim, Young-An ; Um, Myeong-Heon ; Ryoo, Young-Hong ;
Korean Chemical Engineering Research, volume 28, issue 5, 1990, Pages 507~507
This study was carried out to find a new process for the production of
from the Al containing solution which was obtained from domestic alunite and gypsum by the co-precipitation method. Synthetic
could be produced by calcining the co-precipitate
and he pH for co-precipitation of
was 7.5. Synthetic
from this study had good homogeneity and refractoriness of this material was SK 35.
A Mathematical Model for Very Low Radioactive Liquid Waste Treatment by Natural Evaporation
Hwang, Doo-Seong ; Ju, Dong-Pyo ; Kim, Young-Wook ;
Korean Chemical Engineering Research, volume 28, issue 5, 1990, Pages 518~518
An evaporating apparatus containing several vertical canvas for liquid flow was designed to treat very low-level liquid radwastes within restricted area and 0.1wt%
aqueous solutions were evaporated into countercurrently flowing air. The evaporation rate was influenced by various parameters such as the height and clearance of canvas, temperature, humidity and velocity of entering air, temperature and velocity of solution and mass transfer coefficient of the system. Using these parameters, a mathematical model equation was proposed to predict the rate of evaporation. Flux of water vapor calculated from the model equation under various operating conditions was coincided well with experimental one and conditions to increase the rate of evaporation were examined using the model equation.
Prediction of Slab Temperature by the Total Heat Exchange Factor(
)in the Reheating Furnace
Kim, Ki-Hong ; Kim, Kyoung-Tae ; Lee, Yong-Kuk ; Choi, Jae-Ou ;
Korean Chemical Engineering Research, volume 28, issue 5, 1990, Pages 527~527
A new method to determine total heat exchange factor was proposed for the prediction of slab temperature in reheating furnace. This method employed the square of the difference between measured and predicted temperature as an objective function. The slab temperature and surface heat flux were calculated under the condition minimizing the objective function. The real slab temperature in a walking beam type reheating furnace with 36m of its effective length was directly measured by using a heat resistive data logger system. The present method was validated by showing that the predicted slab temperature was in a good agreement with the measured one.
The Oxidative Coupling of Methane over Supported Zinc Oxide Catalyst with Alkali Promoters
Kim, Sang-Chai ; Yu, Eui-Yeon ;
Korean Chemical Engineering Research, volume 28, issue 5, 1990, Pages 536~536
The oxidative coupling of methane to ethylene and ethane was studied over Zn-Oxide catalysts with different compositions of catalysts, different supports and promoters. The selectivity for
) decreased with an increase in the acid sites of supported catalysts. The Zn-Oxide/
catalyst without acid sites showed that a good
) selectivity. The optimal loading of Zn-Oxide was 60wt%. When alkali halide promoters were added to Zn-Oxide/
, the activity order was NaBr>NaCl>Nal>NaF. Br and Cl radicals might play an important role in formation of ethylene, but NaF and alkali metal salts(
) played a role of inhibitor. From kinetic studies on oxidative coupling of methane over NaCl(30wt%)/Zn-Oxide(60wt%)/
, the oxygen species responsible for formation of
, radical was suggested to be diatomic oxygen(
)on the surface. The activation energy was ca. 39 kcal/mole.
Effect of Alkyl Ammonium Perchlorate on Combustion of Composite Propellant
Yim, Yoo-Jin ; Hwang, Kap-Sung ;
Korean Chemical Engineering Research, volume 28, issue 5, 1990, Pages 547~547
The effect of n-alkyl trimethyl ammonium perchlorate(ATAP) on the burning rate of HTPB/IPDI/AP solid propellants was investigated by thermal analysis and burning rate measurement. The reason that the addition of ATAP resulted in decreasing the burning rate of composite solid propellant appeared to be the reduction of the exothermic energy during thermal decomposition rather than the suppression of the decomposition of AP. Since the exothermic energy of ATAP with the large alkyl group was less than that of on with the small alkyl group, the former was more effective on the decrease in the burning rate of composite solid propellent than the latter.
Mixed-Alcohol Synthesis from CO and
Woo, Hee-Chul ; Kim, Young-Gul ; Moon, Sang-Heup ; Nam, In-Sik ; Lee, Jae-Sung ; Chung, Jong-Shik ;
Korean Chemical Engineering Research, volume 28, issue 5, 1990, Pages 552~552
The effects of
content, reaction temperature and pressure on the activity and selectivity of
catalyst for the catalytic hydrogentation of CO producing mixed alcohols were investigated in a high pressure fixed bed reactor. A
catalyst promoted with
showed stable activity and high selectivity for
linear alcohols. The optimal conditions of this reaction system in terms of alcohol productivity were 17wt%
content on the catalyst and
of reaction temperature. The amount of alcohol production depends on the reactor pressure : the higher the reactor pressure, the higher the alcohol yield. The product distribution of
alcohols was well correlated by the Schulz-Flory distribution.
Effect of Floating Bubble Breakers on Gas Phase Holdup, Axial Dispersion and Mass Transfer in Continuous Bubble Columns
Kang, Yong ; Min, Bung-Tae ; Nah, Jong-Bok ; Kim, Sang-Done ;
Korean Chemical Engineering Research, volume 28, issue 5, 1990, Pages 560~560
The effects of gas and liquid velocities and the added volume fraction of floating bubble breakers on gas phase holdup, axial dispersion coefficient of liquid phase and gas-liquid volumetric mass transfer coefficient have been determined in continuous bubble columns with and without floating bubble breakers. The gas phase holdup and volumetric mass transfer coefficient increase up to 13.0 and 25.0% respectively, and the axial dispersion coefficient of liquid phase decreases with the addition of floating bubble breakers to continuous bubble columns. The gas phase holdup, volumetric mass transfer coefficient and axial dispersion coefficient of liquid phase have been correlated with the experimental variables.
Characteristics of the Freeboard Combustion in a Fluidized-Bed Coal Combustor I. Experimental Investigation
Park, Yeong-Seong ; Ghim, Young-Sung ; Son, Jae-Ek ; Maeng, Ki-Suck ;
Korean Chemical Engineering Research, volume 28, issue 5, 1990, Pages 568~568
Characteristics of the freeboard combustion were experimentally investigaed with the low-grade Korean anthracite in a bench-scale fluidized bed combustor. Korean anthracite used in this study had a heating value of about 2500kcal/kg and contained about 60% ash. The axial distribution of temperature,
and CO concentration distribution with respect to freeboard were measured. The fraction of carbon combustion in the freeboard were also estimated. The experimental results showed that carbon combustion reaction in the freeboard mainly depended on coal particle size, bed temperature, and fly ash recycle ratio. The fraction of carbon combustion in the freeboard was found to be in the range of 2-10% without fly ash recycle, however it increased up to 20% with recycling of fly ash. The following correlation was obtained for the fraction of carbon combustion in the freeboard:
Study on the Reaction Mechanism of GaAs Etching in Aqueous Solutions
Nam, Kee-Suk ; Chang, Dong-Bae ; Jung, Suk-Jin ;
Korean Chemical Engineering Research, volume 28, issue 5, 1990, Pages 576~576
The etching reaction of GaAs(100)in HF-oxidizing agent-
mixed soultions was explained using the redox potential of etching solution and the band theory of semiconductor. The etch rates were similar for n-type and p-type GaAs. The higher the energy difference between the valence band of GaAs and the redox potential of etching solution was, the lower the activation energy of the etching reaction was and the etch rate of GaAs was rapider. Laser-induced etching of GaAs(100) with 632.8mm He/Ne laser illumination showed that the etch rate for n-GaAs was dramatically increased while that for p-GaAs was not responsive to laser illumination. The holes formed at the surface of CaAs played an important role in the etching reaction of GaAs. The etch rate increased with the increase of the hole concentration at the surface. The anisotropic etching was obtained by proper use of the etching solutions in the experiment.
Influence of Feedstocks and Carbonization Condition on Pitch Coke Preparation from Various Coal Tars
Choi, Jae-Hoon ; Lee, Gyu-Dong ; Kim, Je-Young ; Park, Yang-Duk ;
Korean Chemical Engineering Research, volume 28, issue 5, 1990, Pages 586~586
Coal tars have been used as feedstocks in order to find guiding principles for the preparation of the high quality pitch cokes. It was compared that the carbonization behavior and the properties of raw coal tars; CTE(Coefficient of Thermal Expansion) values and microtexture of cokes prepared from refined coal tars were also compared. The values of C/H atomic ratio of raw coal tars showed 1.08-1.45. By the refining raw coal tars with solvent extraction method, the anisotropic texture development of pitch cokes has been considerably improved. This coke showed "Flow-domain" texture against mosaic texture from raw coal tar. Coal tar was converted into coke for 45min at
but it took more than 5 hours at
, coking yields and CTE value of cokes were higher than any other temperature. Coking yields were decreased and the textures of coke were mosaic at
. Pitch cokes prepared at
have high coking yield; well-developed anisotropic texture, and low CTE.
Mass Transfer Across Liquid-Liquid Interface -Mass Transfer in an Agitated Vessel with Liquid-Liquid Flat Interface-
Park, Sang-Wook ; Chun, Byung-Soo ; Lim, Gyun-Taek ;
Korean Chemical Engineering Research, volume 28, issue 5, 1990, Pages 594~594
The mass transfer coefficients of a solute through a flat interface of partially miscible binary systems were obtained in an agitated vessel of a modified Lewis cell type. The observed Sherwood number for an aqueous phase,
were correlated in terms of the aqueous Reynolds number,
, Schmidt number,
, Capillary number,
, a function of viscosity ratio,
and the organic phase Reynolds number,
. The correlation among these variables represented with an average deviation of 15.3% as the following equation.
A study on the Preparation of CA-CTA Blended Membrane and Separation Characteristics for Reverse Osmosis Process
Kim, Myeong-Sun ; Lee, Gwang-Hyeon ; Min, Byeong-Ryeol ;
Korean Chemical Engineering Research, volume 28, issue 5, 1990, Pages 602~602
CA-CTA blended membranes for reverse osmosis were prepared by wet-process and tested for the purpose of determining the separation characteristics. The characteristics of these membranes were compared with those of CA-membrane made at the same condition and commercial it. Considering the effect for the solution composition of blended membranes, the membrane which had 16wt% polymer content in the casting solution exhibited highest rejection coefficient. Experimental results showed that rejection coefficient was decreased but permeate was increased with the decreasing of polymer content. With the result of comparison of blended membranes and CA-membranes, the blended membrane which had 16wt% polymer content and 60 seconds evaporation period had higher rejection coefficient than commercial and prepared CA-membranes. When plotting of 1/R vs.
for membranes, data followed the Pusch’s linear model and solution-diffusion model except the lowest polymer composition membrane within experimental boundary.
Reaction Kinetics of Nitrile Hydratase from Brevibacterium sp. CHI
Chang, Ho-Nam ; Lee, Cheo-Young ; Hwang, Jun-Sik ;
Korean Chemical Engineering Research, volume 28, issue 5, 1990, Pages 612~612
The effect of several compounds on the enzyme action of the nitrile hydratase was studied. An excess of acrylonitrile as substrate was shown to inhibit the activity of the enzyme. This inhibition occured at a substrate concentration of 0.2mol/L. The nitrile bioconversion products (acrylamide, propionamide)and their structural analogues(acrylic acid, cyanide) were shown to inhibit the enzyme competitively. The most important inhibition found was that of cyanide(
), a breakdown product of some nitriles.