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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 25, Issue 6 - Dec 1987
Volume 25, Issue 5 - Oct 1987
Volume 25, Issue 4 - Aug 1987
Volume 25, Issue 3 - Jun 1987
Volume 25, Issue 2 - Apr 1987
Volume 25, Issue 1 - Feb 1987
Selecting the target year
Kinetics of Ferrous Ion Oxidation by Dissolved Oxygen in Alkaline Region
Koh, Jea-Cheon ; Lee, Jung-Min ; Rhee, Bo-Sung ;
Korean Chemical Engineering Research, volume 25, issue 5, 1987, Pages 435~435
The kinetics for the oxidation reaction of ferrous ion in alkaline solution in with the dissolved oxygen was determined using initial rate method. The oxidation was conducted by injecting the ferrous ion into NaOH solution and the reaction orders in terms of oxygen consumption were the first order with respect to the ferrous ion concentration but varied with the alkali and the dissolved oxygen concentration. The deflection of reaction order with respect to alkali concentration was found to occur near 0.025 mole/l NaOH concentration. The rate equations for the oxidation were two types according to the temperature level ; one of these was
. The activation energy for the oxidation of ferrous ion was 6.8 Kcal/mole. Amorphous iron oxy-hydroxide(
-FeOOH) which had produced as reacting the iron sulfate to the NaOH in the aforementioned solution was confirmed by the X-ray diffractometer and the IR spectrophotometer.
Burning Rate Catalytic Effects of
in Composite Propellants
Yim, Yoo-Jin ;
Korean Chemical Engineering Research, volume 25, issue 5, 1987, Pages 442~442
In AP/HTPB composite propellants, metallic oxides is generally used for increasing burning rate. Ferric oxide and chromic oxide were known as good burning rate catalysts. Considering the experimental and theoretical approach about these catalysts, the following results were obtained.
was more effective than
for decreasing the activation energy of primary flame reaction, then burning rate of propellant with
was higher than with
for the finer AP propellant. Because the effect of pressure on primary flame distance is less than AP flame distance, the pressure exponent on burning rate of propellant with
was higher than with
. In aluminized propellants, the burning rate discrepancy of two catalysts and pressure exponent were decreased with increasing aluminium content. The reasons were that the effect of heat sink of aluminium was increased and the amount of other flame energies was relatively decreased.
into CMC-NaOH Aqueous Solution in a Wetted-Wall Column
Park, Sang-Wook ; Park, Pan-Wook ; Kim, Seung-Soo ; Yun, Jong-Won ;
Korean Chemical Engineering Research, volume 25, issue 5, 1987, Pages 447~447
The rate of absorption of carbon dioxide into water, aqueous sodium hydroxide, CMC(carboxymethy1 cellulose), and sodium hydroxide-CMC has been measured by various changes of contact time between gas and liquid using a wetted-wall column at
. The experimental data were analysed by the penetration theory based on the gas absorption with second order irreversible chemical reaction
. The measured reaction enhancement factors were consistent with those predicted by the approximated equation derived by Hikita et al. within the range of
of experimental error. The mechanism of gas absorption with reaction into Newtonian liquid could be also used in the case of Power-law liquids.
Deactivation of Supported Copper Chromite Catalyst by Sulfur Dioxide or Water Vapor
Kim, Yong-Woo ; Rhee, Hyun-Ku ; Kim, Young-Yhil ; Choi, Ik-Soo ;
Korean Chemical Engineering Research, volume 25, issue 5, 1987, Pages 454~454
Copper chromite catalyst has a potential for use in automobile exhaust emission control. Here an experimental study has been carried out to examine the effects of sulfur dioxide and water vapor on carbon monoxide oxidation over supported copper chromite catalyst. The degree of deactivation of the catalyst under exposure to sulfur dioxide was rather severe, especially at the carbonyl site on the catalytic surface. The decrease in catalytic activity by poisoning tended to accelerate at low temperature and at high concentration of sulfur dioxide. It was only at very low concentration of sulfur dioxide that the catalyst maintained its activity to some extent. For the catalyst that maintained more than 20% of its intrinsic activity, its activity was fully recovered by heating at
. Once completely poisoned, however, the catalyst could not be regenerated by heating or washing. The catalytic activity also tended to decrease in the presence of the water vapor if the reaction temperature was below
. At higher temperatures above
the effect of water vapor was found negligible. The catalyst deactivated by water vapor at low temperature recovered its original activity simply by heating. This implies that deactivation by water vapor is most likely due to the adsorption of water vapor.
Axial and Radial Mixing Characteristics in Bubble Columns
Kang, Yong ; Lim, Wan-Mook ; Kim, Sang-Done ;
Korean Chemical Engineering Research, volume 25, issue 5, 1987, Pages 460~460
Gas holdup and axial and radial dispersion coefficients of continuous liquid phase have been studied in a 10.2 cm-ID acryl column. The effects of gas flow rate (1.0-10.0cm/s) and liquid flow rate (2.0-12.0 cm/s) on the hydrodynamic characteristics of a bubble column have been determined. Gas holdup, axial and radial dispersion coefficients of liquid phase, and liquid circulation velocity in the column were increased with an increase in gas flow rate. However, increasing liquid flow rate the gas holdup was decreased and the radial dispersion coefficient of liquid phase was increased. The axial dispersion coefficient and the circulation velocity of liquid phase were little affected by the liquid flow rate. Bubble rising velocity in the column was analyzed by employing the drift flux model, and the two dispersion coefficients of liquid phase were correlated by means of isotropic turbulence model.
Carbon-Deactivation and Regeneration of Supported Cobalt and Nickel Catalysts
Mun, Sang-Heup ; Lee, Sang-Won ; Seong, Byeok-PaJeong ;
Korean Chemical Engineering Research, volume 25, issue 5, 1987, Pages 468~468
Adsorption properties and activity of cobalt and nickel catalysts have been studied by temperature programmed desorption (TPD) of carbon monoxide and by methanation test, as the catalysts are contaminated by surface carbon and are regenerated by hydrogen treatment thereafter. Carbon on the catalyst surface has been accumulated by disproportionation of carbon monoxide at elevated temperatures. It has been observed that catalysts with surface carbon deposited at
are deactivated more rapidly than those with carbon deposited at
, and also that the former are more easily regenerated by hydrogen treatment than the latter. Cobalt undergoes more severe deactivation than nickel by surface carbon accumulation, but it is readily regenerated by hydrogen treatment. In this study, catalyst deactivation by surface carbon could be monitored by changes in the TPD chromatogram, which showed reduction of peaks below
accompanied by a new peak appearing above
. However, the catalyst regeneration process could not be monitored in this manner, which may suggest that the structure of the catalyst has been modified during the deactivation and regeneration processes.
Synthesis of A, Y and Mordenite Type Zeolite from a White Carbon
Kim, Geon-Joong ; Jung, Sang-Jin ; Kim, Tae-Joon ; Kwon, Lee-Mook ;
Korean Chemical Engineering Research, volume 25, issue 5, 1987, Pages 477~477
The A, Y and Mordenite type zeolites were synthesized in high purity and good yield by hydrothermal method with Zeosil 45(a White carbon) as a silica source. And the effect of the factors such as reactants composition, aging time, reaction temperature and reaction time which can influence on the crystallization of the zeolites were investigated. In this experiment, the composition of substrates able to produce these zeolites were as follows; for
. For the synthesis of NaA and NaY, aging at room temperature was an essential step, but it exhibited negative effect of the synthesis of Na-Mordenite. However, even in the borderland of suitable substrate compositions for the synthesis of NaA and NaY, the aging time at room temperature and the time of hydrothermal reaction were prolonged, NaA transformed to Hydroxy-sodalite and NaY to P-type zeolite. For the crystallization of A and Faujasite type zeolite, it was believed that the precursors of the zeolite were formed in the aging step at room temperature. But for the nucleation of Na-Mordenite, it was seemed that the nuclei were formed during a hydrothermal reaction at high temperature rather than at room temperature through the formation of precursors with reactive silica particles as core. The activation energies for the nucleation and the crystal growth step of NaA, NaY and Na-Mordenite were 17, 42, 67 KJ/mole and 34, 42, 57 KJ/mole, respectively. Zeosil, which was used in this experiment, was very reactive and seemed to be a useful silica raw material particularly for the synthesis of high silica zeolites, such as Mordenite and the Pentasil-family.
Properties of Potassium-Added Nickel Catalysts Supported on
Suh, Dong-Jin ; Moon, Sang-Heup ; Ihm, Son-Ki ;
Korean Chemical Engineering Research, volume 25, issue 5, 1987, Pages 486~486
Nickel catalysts supported on alumina have been studied about their adsorption properties and kinetic behavior of CO hydrogenation as potassium is added up to 2 wt%. Potassium changes not only the structural properties of the nickel catalyst such as the extent of reduction, dispersion and particle size, but also its adsorption strength to hydrogen and carbon monoxide. With potassium addition, nickel adsorbs hydrogen more weakly and carbon monoxide more strongly. Adsorbed carbon monoxide dissociates easily on the potassium-promoted catalyst to accumulate surface carbon. Supported nickel catalysts lose their initial CO hydrogenation activity and show enhanced selectivity for higher hydrocarbons and olefins as potassium is added to them. When the reaction rate is expressed by a power law for the reactant partial pressures, its pressure dependency on carbon monoxide decreases, that on hydrogen increases, and the activation energy of methanation increases with potassium addition to nickel. The above results may be explained from the adsorption properties of potassium-added nickel catalysts for hydrogen and carbon monoxide.
Gas-phase Isomerization of Xylene over HY-Zeolite and Pt-Loaded HY-Zeolite
Lee, Gun-Dae ; Lee, Ho-In ;
Korean Chemical Engineering Research, volume 25, issue 5, 1987, Pages 497~497
The mechanism of xylene isomerization over HY-zeolite and Pt-loaded HY-zeolite (Pt/HY) was studied. And the isomerization of mixed xylene containing ethylbenzene over the above catalysts was also investigated. As the results of experiments, vapor-phase isomerization of xylene over HY-zeolite proceeded via intermolecular transalkylation mechanism and intramolecular 1,2-methyl shift mechanism simultaneously, and the contribution of each mechanism to the overall reaction depended on reaction condition. Over Pt/HY, the isomerization of xylene occurred through hydrogenated intermediates and had tendency to proceed via the route involving more stable carbocation preferentially. In the isomerization of mixed xylene over HY-zeolite, the extent of transalkylation of ethylbenzene was higher than that of xylene.
Mechanical Properties of Carbon Fiber-Mesophase Pitch Composites
Rhee, Bo-Sung ; Ryu, Seung-Kon ; Joo, Hyeok-Jong ; Jeong, Bal ;
Korean Chemical Engineering Research, volume 25, issue 5, 1987, Pages 504~504
The mechanical properties of carbon fiber-mesophase pitch composites were affected by surface treatment of carbon fiber, preparation of mesophase pitch precursor, prepreg fabrication, moulding, carbonization, and so on. Impregnation and recarbonization is one of the methods of improving the mechanical properties. High-modulus carbon fiber was anodic oxidized in 30% sulfuric acid for 5 minutes to improve bonding between the fiber and the matrix. Uni-directional prepregs which were made by surface treated fiber and mesophase pitch precursor were laminated again with mesophase pitch precursor powder in a moulder and hot-pressed up to
, which was carbonized up to
at the heating rate of
/h. This green composite was impregnated, pressure carbonized, and recarbonized four cycles. As a result, the specimen which contained about 58 % fiber volume shows the density of
, the ILSS of
, the flexural strength of
, and the flexural modulus of
. However, in spite of four cycles of impregnation/recarbonization, the empirical values of mechanical properties were less than theoretical values as much as 5-20%, because of some micropores which were not impregnated by matrix so far.
Vapor-Liquid Equilibria of Oxazole-Acetonitrile, Oxazole-Water, and Acetonitrile-Water Systems by Head Space Analysis
Park, So-Jin ; Choi, Byong-Hyock ; Rhee, Bo-Sung ;
Korean Chemical Engineering Research, volume 25, issue 5, 1987, Pages 512~512
Isothermal vapor-liquid equilibria have been determined for oxazole-acetonitrile, oxazole-water, acetonitrile-water at
using head space gas chromatography (H.S.G.C.) as static method. The algorithm of computation is newly made and used in this study. This makes experiment more simply and rapidly. The system acetonitrile-water forms a minimum b.p azeotrope, while the other two systems did not have the azeotrope. To testify the new algorithm, which used in this study we compared the VLE data of system acetonitrile-water with the literature data, and the thermodynamic consistency test was also carried out. The result of both attempt were very good. Therefore new data of the vapor-liquid equilibria for the system oxazole-acetonitrile, oxazole-water are reliable, and also with sufficient reliability the new computation algorithm in this study is suggestible.
A Study on Curing Kinetics of Unsaturated Polyester Resin
Shin, Sang-Hee ; Suh, Moon-Ho ; Lee, Suck-Hyun ; Yie, Jae-Eui ; Lee, Jae-Wook ;
Korean Chemical Engineering Research, volume 25, issue 5, 1987, Pages 522~522
The curing kinetics of unsaturated polyester resin with benzoyl peroxide was studied within the temperature range of
. A modified kinetic expression was devised by introducing cure induction time and maximum degree of cure, and the kinetic parameters were determined using differential scanning calorimetry. We also carried out both numerical and experimental studies on compression molding processes of the resin system in order to test the proposed kinetic equation. From the results, it was found that the present kinetic expression enabled us to predict the molding process successfully.
Characteristics of a Screen-Packed Fixed Bed -velocity and temperature distributions-
Kim, Bong-Hyun ; Chun, Hai-Soo ;
Korean Chemical Engineering Research, volume 25, issue 5, 1987, Pages 528~528
To investigate the effects of void fraction and the screen-packing in the fixed bed on radial velocity- and temperature distributions of the bed, local velocities and temperatures of fluid on the glass bead fixed bed and on that inserting the screen-packing are measured by using the two-channel hot-wire anemometer at the isothermal or transient conditions. It is found that the radial velocity-and temperature-profiles are non-uniform due to the variation of void fraction near the wall. The screen-packing in the bed enables fluid-flow to be uniformly distributed over the bed and to bring about the uniform radial temperature profile over the bed. The differential equations which govern the velocity- and temperature-distributions of the fixed bed are numerically solved to demonstrate the effects of the void fraction and the screen-packing inserted in the bed.