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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
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Volume & Issues
Volume 23, Issue 6 - Dec 1985
Volume 23, Issue 5 - Oct 1985
Volume 23, Issue 4 - Aug 1985
Volume 23, Issue 3 - Jun 1985
Volume 23, Issue 2 - Apr 1985
Volume 23, Issue 1 - Feb 1985
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Effects of Metal Stearates and Oxygen on Kinetics of Thermal Decomposition of Polyvinyl Chloride
Chung, In-Jae ; Hong, Myung-Sun ;
Korean Chemical Engineering Research, volume 23, issue 5, 1985, Pages 281~281
Effects of metal stearates on kinetics of first stage carbonization of PVC were studied on the reaction mechanism of S + gG - g'G' + rR, that is, one gram of PVC(S) is decomposed to the g' grams of gas(G') and r gram of residue(R). The reaction rate was obtained by analyzing the thermogravimetric curve measured under a constant heating rate. Pure PVC has the reaction order of 3/2 with respect to residual solid weight, while PVC with a metal stearate has first order reaction. From these results, a new reaction mechanism is suggested to explain the thermal decomposition of PVC with metal stearates. As the oxygen concentration increases, all samples except for PVC with zinc stearate has lower activation energy and easily decomposes while PVC with zinc stearate shows higher activation energy in the low oxygen concentration range because the probable formation of zinc oxide suppresses the formation of zinc chloride which accelerates dehydrochlorination.
Effect of Hydrogen Treatment on Zinc Oxide Catalyst Supported over Kieselguhr
Hong, Myung-Sun ; Park, Sang-Eon ;
Korean Chemical Engineering Research, volume 23, issue 5, 1985, Pages 289~289
In manufacturing methyl ethyl ketone by dehydrogenation of secondary-butyl alcohol, the hydrogen treatment of zinc oxide enhances the catalytic activity and the selectivity with decreasing dehydration reaction. Also, the catalyst lifetime of hydrogen treated zinc oxide is much longer than that of nonhydrogen-treated zinc oxide. But, excessive hydrogen treatment of zinc oxide catalyst leads to the cluster phenomenon to form zinc crystallite which results in deactivation of dehydrogenation reaction.
Investigation on the Crystal Growth of Zeolite A with Aging Step
Seo, Gon ;
Korean Chemical Engineering Research, volume 23, issue 5, 1985, Pages 295~295
The crystal growth of zeolite A from the reactant having aging step was studied. The nuclei formation in aging step was confirmed with the linear increase of crystal size for the crystallization time. The concentration of nuclei formed during aging step in this experiment was
and rate constant for crystal growth of zeolite A
. When the sufficient amount of nuclei was formed through the aging step, the crystal growth rate was related with diffusion restriction, concentration of nuclei and the reactant, and the total surface area of zeolite A in the reactant. The cube root of the formation ratio of zeolite A satisfied the linear relationship with crystallization time, when armorphous solid was present.
Removal of Orthophosphates from Aqueous Solutions by Activated Carbon
Koh, Kyung-Jin ; Chung, Jay-Gwan ;
Korean Chemical Engineering Research, volume 23, issue 5, 1985, Pages 303~303
The liquid-solid type reaction encountered in this study is usually complicated by the presence of resistances as a result of film diffusion across the external solid surface and particle diffusion through the pores of solid. Therefore, it became necessary to establish the operating conditions that minimized the influence of film and particle diffusion. This investigation was an attempt to eliminate these diffusional effects and determine the kinetics of the removal of orthophosphates from the aqueous solutions by activated carbon using a differential bed reactor approach. The reaction kinetics studied in this experiment may be summarized as follows:
A comparison of these equations indicates that the reaction kinetics at pH 4.0 is much faster as compared to those at pH 8.0 and 12.0. The equilibrium adsorption studies support the existence of this adsorption isotherm which fits the empirical Freundlich isotherm, comparatively. For activated carbon, maximum orthophosphates adsorption occured at pH 4.5 - 7.0 with decreasing amounts of adsorption at lower and higher pH.
Adsorption Characteristics of Cd-Chelate Compounds on Activated Carbon
Lee, Jong-Jib ; Chang, Yoon-Ho ; Cho, Byung-Rin ;
Korean Chemical Engineering Research, volume 23, issue 5, 1985, Pages 313~313
The effects of PH, molar ratio [Rm = chelating agent/Cd(II), mol/mol], adsorptivity of chelating agent and ligand for adsorption of Cd(II) by activated carbon were investigated by using Amino carbonic acid group (NTA, EDTA, DTPA) and Amin group (Phen., TEA) as a chelating agents. It was found that the optimal PH was shifted with the increasing molar ratio (Rm) of EDTA, DTPA and Phen. and that TEA and NTA were not useful to remove Cadmium ion. Under the optimal condition PH=5, Rm=1 (DTPA) and PH=5, Rm=10 (Phen.), the removal percent of Cd(II) [initial concentration=10 mg/1] was about 95%.
Experimental and Theoretical Studies of Convective Heat Transfer in a Porous Medium
Shin, An-Shik ; Lee, Jae-Wook ; Suh, Moon-Ho ;
Korean Chemical Engineering Research, volume 23, issue 5, 1985, Pages 321~321
The phenomena of natural convection in a fluid-saturated porous medium were studied experimentally for a wide range of Rayleigh number. The experiments were carried out in a rectangular glass tank of very small width to facilitate flow visualization. Mixtures of glass beads and distilled water were used as a porous bed. The bed was heated from below and cooled from above, and the flow was visualized by photographing dye streaks. A theoretical analysis was also included to simulated the experimental results. In the analysis the thin rectangular box was thought of a fin losing heat to the surroundings in order to examine the effect of lateral heat losses. The experimental results contain both quantitative information on the temperature fields and flow visualizations on the various convective flow patterns. The convective flow behavior of the numerical simulation was qualitatively identical to that of the experiment.
Spherical Agglomeration Mechanism by Wet Processing Technique -Effect of Experimental Factors on the Size of Agglomerates and Its Distribution-
Choi, Woo-Sik ;
Korean Chemical Engineering Research, volume 23, issue 5, 1985, Pages 329~329
The mechanism of spherical agglomeration in the wet system is examined with agitating the suspension of fine particles in organic liquid, with small added amount of a second bringing liquid, which preferently wets the particles. The spherical agglomerates can be produced in a cylindrical vessel equipped with the turbine type of rotating agitator, using mainly the calcium carbonate-chloroform-water system. The spherical microagglomerates were formed when the bridging liquid was occupied between 51% and 90% of the void volume among the agglomerated products. The particle size distribution of agglomerates was found to take the Rosin-Rammler's distrinution function. It was also found that the size of agglomerates was increased with the increase of total specific net input energy during agglomeration process and it could be controlled by experimental factors such as added amount of bridging liquid, agitation speed, and agitation time. Furthermore, the size of agglomerates was expressed with the function of cohesive factors involved in the wet system based on the equilibrium state of cohesive force and destructive force.
Monte Carlo Simulation on Temporal and Spatial Oscillations of the Belousov- Zhabotinskii Reaction
Yoo, Je-Kang ; Park, Dae-Gyu ; Yoo, Kyong-Ok ;
Korean Chemical Engineering Research, volume 23, issue 5, 1985, Pages 337~337
A Monte Carlo Algorithm, capable of simulating numerically the time behavior of a spatially homogeneous reaction system, is expanded to include diffusion process. This expanded algorithm is applied to the Oregonator model of the Belousov-Zhabotinskii reaction to study the phenomenon of spatial oscillations. The results show that trigger waves travel at constant velocity which is uniquely determined by the given properties of the system and the velocity of trigger wave propagation increases linearly with the square root of both [
] and [
]. The Monte Carlo algorithm for a homogeneous reaction system is also applied to the Oregonator model of the Belousov-Zhabotinskii reaction to study the phenomenon of temporal oscillations. The results show that the period of oscillation is 54 sec and the concentrations of intermediates exhibit the limit cycle behavior in phase plane. These results from the Monte Carlo algorithm are compared with the previous experimental results and with the simulation results obtained by a finite difference method.
Analysis of a Fixed- Bed Adsorption-Reaction System with Freundlich Isotherm(I)
Nam, Young-Woo ; Rhee, Hyun-Ku ;
Korean Chemical Engineering Research, volume 23, issue 5, 1985, Pages 349~349
Material balance for the reactant in a fixed-bed adsorption-reaction system is formulated to give a quasilinear partial differential equation of first-order. The equation is then solved analytically by applying the method of characteristics and the theory of mathematical shock. Freundlich isotherm is adopted for the equilibrium relationship whereas the reaction considered takes place in the fluid phase, being of first-order and irreversible. From the adsorption system without reaction the system behavoir is investigated when the adsorbate feed concentration undergoes a change of a step, a square wave, or an impulse. Concerning the adsorption-reaction system, it is assumed that only the reactant is adsorbable and the system behavoir is analyzed when the reactant feed concentration undergoes a change of a step or a square wave. The result shows that the reactant conversion is improved while partial separation between the reactant and the product is accomplished.