Go to the main menu
Skip to content
Go to bottom
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 32, Issue 6 - Dec 1994
Volume 32, Issue 5 - Oct 1994
Volume 32, Issue 4 - Aug 1994
Volume 32, Issue 3 - Jun 1994
Volume 32, Issue 2 - Apr 1994
Volume 32, Issue 1 - Feb 1994
Selecting the target year
Near Optimal Production Sequencing for Multiproduct Batch Processes with Heuristics
Kim, Kyeong-Sook ; Cho, Young-Sang ; Rhee, Hyun-Ku ;
Korean Chemical Engineering Research, volume 32, issue 3, 1994, Pages 265~265
The determination of a production sequence is an important problem in a batch process operation. In this paper, newly modified algorithms for a near optimal production sequence of N products in a M unit serial batch process are proposed. The basic principles are taken from the extended Johnson’s algorithm and the RA algorithm. Test results on a number of selected examples exhibit the superiority of the newly modified algorithm.
Performance Test of Additives for Simultaneous Removal of
from Flue Gas
Lee, Hyung-Keun ; Cho, Hang-Dae ; Kim, Sung-Hyun ;
Korean Chemical Engineering Research, volume 32, issue 3, 1994, Pages 273~273
A bubbling type reactor for simultaneous removal of
was built to test the performance of yellow phosphorous and limestone. Factors affecting NO removal efficiency and phosphorous utilization in this system such as mixing degree, flow rate of flue gas,
concentration, concentration of NO and
in the flue gas were investigated. This method showed good results for NO removal efficiency of phosphorous emulsions over wide range of NO concentrations. It means that this method can be applied for treatment of NO emission from other sources. White fume produced by reaction of
in the reactor can be recovered above 98% as phosphoric acid and phosphorous acid using a washing column. Using
and limestone, both
and NO in the flue gas can be removed above 98%, and pH of solutions were maintained in the level of 2.5-3.0.
Hydrogen Encapsulation in Cs Ion-Exchanged Zeolite A: Model Development and Comparison with Experiment
Kim, Dong-Hyun ; Heo, Nam-Ho ; Kim, Jong-Taik ;
Korean Chemical Engineering Research, volume 32, issue 3, 1994, Pages 281~281
A mathematical model is developed for hydrogen encapsulation in Cs ion-exchanged zeolite A. In comparison with the previous mode on encapsulation, the present model correctly considers the route to
-cage encapsulation in that hydrogen molecules are allowed to enter into a
-cage only from the neighboring
-cage through toe
-window connecting the two cages. When the model is applied to temperature programmed decapsulation, excellent agreements were observed between the model predictions and the experimental data. In the investigated range, no influence of the encapsulation pressure was found on the diffusivity through
-cages and on the mass transfer coefficient between the two types of cages. Also the encapsulation temperature had no effect on the isotherms of
-cage concentration versus
-cage concentration, indicating that the energy level of the hydrogen molecule is the same in both cages.
A Study on Optimal Heat Exchanger Network Synthesis Using System Separation Method
Lee, Hae-Pyeong ; Yoo, Kyong-Ok ;
Korean Chemical Engineering Research, volume 32, issue 3, 1994, Pages 288~288
The optimal minimum temperature difference and the optimal total cost targets based on the energy and capital cost were determined before the synthesis of the heat exchanger network. The present method using the system separation, was applied to the system which have the discontinuity on the temperature-enthalpy diagram, the multiple pinches and the match constraints for the intangibles of design such as safety, layout and etc. The program based on the above method was developed and it was possible simply to find the optimal target for the actual heat exchanger network by the pinch design rule.
A Study on Separation and Recovery of Valuable Metals from Fly Ash
Lee, Sung-Sik ; Kang, Bong-Geun ; Kim, Jong-Hwa ;
Korean Chemical Engineering Research, volume 32, issue 3, 1994, Pages 300~300
Fly ash as industrial waste can be divided into coal fly ash and heavy oil fly ash. Since the fly ash contains lost of metallic oxides, it can be treated as a second resource from which various valuable metals may be separated, recovered and refined. The leachants of fly ash are hydrochloric acid, sulfuric acid and water. The heavy oil fly ash contains a high concentration of Ni, V, Ga and so on, while the leaching solution from coal fly ash has poorer contents of soluble metal ions than the heavy oil fly ash. Before the recovery, the adsorption or ion exchange method was used as pre-treatment. For an efficient leaching, two steps were taken to prevent any disturbance from other metal ions. Such extractants as LIX51, TBP(100%), TOPO, TOMAC and D2EHPA were used in order to separate, recover and refine Ga and V from the leaching solution. Gallium was extracted as much as nearly 100% at the concentration of 2M-HCl when used to the concentration of 0.1M TOMAC as extractant, and the extraction of Fe(III) showed a similar tendency. The selective extraction of Ga could be proceeded after
two times as much as Fe equivalent was added to aqueous solution. The refinement by way of vanadium extraction appeared in the order of TOMAC>DP-8R >LIX51 at the range of pH 0-3. The precipitation of co-existent iron ions from raffinate could be removed by controlling pH at 3 or higher.
A study on Prediction of Ternary Ion Exchange Equilibria in Zeolite NaA
Kim, Sang-Won ; Han, Sang-Sup ; Cho, Chan-Hwi ; Lee, Han-Ju ;
Korean Chemical Engineering Research, volume 32, issue 3, 1994, Pages 308~308
A study has been made to predict multicomponent ion exchange equilibria data from the corresponding binary isotherms in zeolite NaA, Na/Sr/Cs and Na/Ca/Mg ternary isotherms are presented, together with isotherms for the six binary system (Na/Sr, Na/Cs, Sr/Cs, Na/Ca, Na/Mg and Ca/Mg systems). Predictive equations for these ternary systems could be solved iteratively using activity coefficients and thermodynamic equilibrium constants for the binary systems obtained from experimental data. The zeolite phase activity coefficients were obtained from the Wilson model. Na/Sr/Cs ternary system displayed high selectivity for
ion and the presence of
ion significantly influenced the relative selectivity of Na/Cs in this ternary system. Na/Ca/Mg ternary system showed high selectivity for
ion and equilibrium of this system was not significantly affected by the introduction of a third ion. The prediction method was found to be in agreement with experimental data within 15-20% relative error.
Kinetics and Catalyst Deactivation for Methyl Formate Synthesis by Methanol Carbonylation
Choi, Seok-Ju ; Lee, Jae-Sung ; Kim, Young-Gul ;
Korean Chemical Engineering Research, volume 32, issue 3, 1994, Pages 317~317
Kinetics and catalyst deactivation have been studied for methyl formate synthesis by methanol carbonylation. In a liquid phase reaction, alkali catalysts drove the methanol carbonylation rapidly to equilibrium and showed almost 100% selectivity to methyl formate. A kinetic study showed that the reaction was of first order both in methanol and CO concentrations. The rate depended on alkali metal of the catalyst in the order, K>Na>Li. A rate equation was derived from a mechanism which assumed that alcoholate ion was the active catalytic intermediate. The equation fitted the experimental data satisfactorily. The catalyst was indeed sensitive to the small amount of
added to the reaction mixture. It was almost completely deactivated when more than a stoichiometric amount of
relative to the amount of the catalyst was added.
Construction of Computer Controlled Langmuir Trough and Its Performance Test
Jung, Sang-Don ; Kim, Jang-Joo ; Park, Sin-Chong ;
Korean Chemical Engineering Research, volume 32, issue 3, 1994, Pages 325~325
A fully computer controlled normal type Langmuir trough was successfully constructed. The constructed Langmuir trough is consisted of a PTFE trough, servomechanisms for the barrier and the dipper and a commercial electronic balance modified for the surface pressure measurement. Surface pressure was measured and controlled with an accuracy of 0.025mN/m. It was successfully used for various supplementary experiments measuring surface potential of a monolayer at the air/water interface and contact angle during monolayer transfer onto a substrate. The trough was used for obtaining the surface pressure-area isotherm or barium stearate and transferring the floating monolayer of barium stearate. The bi-layer thickness of transferred Langmuir-Blodgett film was obtained from XRD. Extrapolated area of
at zero surface pressure for solid phase occupied by a molecule, linear decrease of monolayer area during the transfer and the bilayer thickness of
demonstrate that the constructed Langmuir trough is suitable for the measuring the isotherm and the transferring the floating monolayers.
A Study on Thin Films Deposited by ECR Plasma CVD Method : Hydrogenated Amorphous Silicon Films
Lim, Tae-Hoon ; Huh, Yun-Jun ; Park, Tae-Jin ;
Korean Chemical Engineering Research, volume 32, issue 3, 1994, Pages 332~332
Characteristics of the hydrogenated amorphous silicon(a-Si:H) films prepared by the electron cyclotron resonance plasma chemical vapor deposition(ECRP CVD) method at low pressure(
) were studied. Deposition rate, hydrogen content and surface roughness were investigated under various deposition conditions such as substrate temperature, partial pressure of
and microwave power. The hydrogen content in the deposited films decreased with the increase of the microwave power and
partial pressure, but increased with the substrate temperature. The deposition rate depended greatly upon the microwave power and partial pressure of
, but slightly upon substrate temperature. The roughness of the deposited film surface was improved as substrate temperature and microwave power increased.
Adsorption Equilibria of Freon-113 on Activated Carbons
Lim, Jin-Gyu ; Chang, Won-Chul ; Lee, Tae-Jin ; Shim, Jae-Jin ; Choi, Dae-Ki ; Lee, Youn-Yong ;
Korean Chemical Engineering Research, volume 32, issue 3, 1994, Pages 341~341
Adsorption equilibria of Freon-113(trichlorotrifluoroethane,
) on two activated carbons were measured at 298-473 K by using a static adsorption apparatus. Granular activated carbon(Norit B4, crushed 20-40 mesh) and activated carbon fiber(KF-1500) were used as adsorbents. They were regenerated overnight at 473 K under vacuum condition before experiments. The portion of the reversible to the total uptake increased with temperature and the adsorption at 473 K was found to be completely reversible. All the isotherms obtained in this study were type I. They showed no apparent hysteresis. The heat of adsorption calculated from Clausius-Clapeyron equation remained nearly constant irrespective of the surface coverage. Experimental data were correlated by BET, Langmuir, and Dubinin-Astakhov equations.
Optical Recording Characteristics for Write Once Disc of Bi Thin Film
Lee, Jong-Dae ; Kim, Chang-Su ; Lee, Dong-Chul ;
Korean Chemical Engineering Research, volume 32, issue 3, 1994, Pages 348~348
The deposition and optical recording characteristics of Bi thin film were investigated using the DC/RF magnetron sputtering unit and the semiconductor laser. It was found that the deposited film thickness increased with increasing power density, sputtering time, argon gas flow rate and decreasing distance between the polycarbonate substrate and Bi target. Before the laser marking, the reflectance of 47% was obtained for the film thickness ranging from
. Also, in comparison with the standard pit length defined by the Red Book, it was shown that the measured pit length was somewhat small.
Electroless Nickel Plating on Alumina Powders
Park, Hee-Jae ; Oh, Eui-Kyeong ; Kim, Sun-Geon ; Yeu, Tae-Whan ;
Korean Chemical Engineering Research, volume 32, issue 3, 1994, Pages 358~358
The activated surface of
alumina powders was chemically plated to form nickel-phosphorous films by slow addition of the reactants-nickel salt and sodium hypophosphite solutions-. This semibatch type of reaction mode could control the plating rate easily and guarantee the adhesion of the film to the powder surface and the suppression of the undesirable particle production in broader range of the plating conditions. The semibatch type also made it possible to prepare the plated powders with better chemical, electrical and magnetic properties. The pH of the reacting system, the molar ratio and the input rate of the reactants had great effects on the rate of plating, the electrical resistivity, the chemical composition, the adhesion and the magnetic property of the film.
A Study on the Rate of Copper Extraction by Alkyl
Shin, Jeong-Ho ; Jeong, Kap-Seop ; Lee, Sang-Hoon ; Lee, Ju-Young ;
Korean Chemical Engineering Research, volume 32, issue 3, 1994, Pages 367~367
The kinetics of copper extraction by several alkyl
-diketones diluted with chloroform was investigated using a flat-stirred cell of constant interfacial area at
. The extraction rate was experimentally determined by analyzing the effects of the concentration of extractants in the organic phase, the concentrations of copper and hydrogen ion in aqueous phase on the initial rate of extraction. The rate constants of chelate formation and initial extraction were determined from the comparison of the experimental results with the theoretical rate obtained by assuming the interface reaction with diffusion in aqueous film. The rate determining step of copper extraction by
-diketones was found to be the reaction of 1:1 chelate formation of irreversible pseudo-first order reaction and the extracted species was
Changes in Combustion Characteristics of Coals after Treatment with Molten Caustic Leaching
Lee, Si-Hyun ; Shon, Eung-Kwon ;
Korean Chemical Engineering Research, volume 32, issue 3, 1994, Pages 376~376
Korean anthracite, JangSung coal, has been treated with molten caustic leaching using several reaction temperatures, NaOH/coal ratios and particle sizes of raw coals. Ash removal rates, Variations in combustion temperatures and combustion rates after treatment were investigated by using TGA(Thermogravimetric Analyser). Results for a typical bituminous coal and a foreign anthracite at a fixed condition of
, NaOH/coal ratio of 4 were also compared with that for a JangSung coal. It had been found for JangSung Coal that the ash removal rates were 64-88% and the combustion peak temperature lowered about
after treatment so that the combustion range of treated coal became similar to that of bituminous coal. Variations in particle size, surface area after treatment were measured and the ratio of volatile matter to fixed carbon(VM/FC) representing coal rank were calculated. The relationship between VM/FC ratio and the variations in combustion temperatures after treatment was discussed briefly.
Supercritical Water Oxidation of Nitrogen Containing Aromatic Compounds
Koo, Chan ; Lee, Dong-Soo ;
Korean Chemical Engineering Research, volume 32, issue 3, 1994, Pages 385~385
The performance of supercritical water oxidation(SCWO) was investigated for the destruction of pyridine, aniline, nitrobenzene. Three aromatic compounds including benzene, toluene, and phenol were also tested under similar conditions for the comparison of destruction performance of SCWO. Pyridine was the most difficult to destroy, nitrobenzene being the easiest among the three compounds with nitrogen. The destruction rates of the three aromatic compounds with nitrogen were slower than the other three without nitrogen. All the major organic by-products from the three nitrogen containing compounds were identified as having the aromatic ring structures. Virtually all(80-100%) of nitrogen from the destruction of pyridine was converted to ammonia. Less portion(50-70%)of nitrogen was converted to ammonia in SCWO of aniline. The ammonia yield was less than 10% of nitrogen from the destruction of nitrobenzene. Neither nitrite ion nor nitrate ion were formed in appreciable quantities. Significant portion of nitrogen from the SCWO of aniline and nitrobenzene is expected to be converted to nitrogen gas(
). It appears that reaction temperatures substantially higher than
and/or catalysts are required for the faster and complete destruction of these nitrogen containing aromatic compounds by SCWO.
Transfer Characteristics of Monolayers of Stereoregular Poly(Methyl Methacrylates)
Jung, Sang-Don ; Kim, Jang-Joo ; Choi, Chang-Kyun ;
Korean Chemical Engineering Research, volume 32, issue 3, 1994, Pages 393~393
The effects of the transfer pressure, types of the substrates and stereoregularity on the transfer characteristics of monolayers of stereoregular PMMAs were systematically investigated in terms of the average transfer ratio. Along with the transfer characteristics, surface pressure-area and surface potential-area isotherms of the monolayers were measured. Z-type multilayers were formed at a transfer pressure below
for the atactic and syndiotactic PMMAs and below
for the isotactic PMMA, respectively. The average transfer ratio of the downward stroke increased as the transfer pressure increased from the above values, forming Y-type multilayers at the transfer pressure of
for the atactic PMMA and syndiotactic PMMAs and at
for the isotactic PMMA, respectively. The effect of the types of the substrate on the transfer characteristics was not significant except for the glass substrate when the transferred first layers were baked. The molecular arrangement of the floating monolayers deduced from the apparent dipole moment was found to be informative in interpreting the transfer characteristics of the monolayers of stereo regular PMMAs.
Selective Catalytic Reduction of Nitrogen Oxide by Hydrocarbons over Mordenite-Type Zeolite Catalysts
Kim, Moon-Hyeon ; Nam, In-Sik ; Kim, Young-Gul ; Lee, Joong-Kee ; Park, Dal-Keun ;
Korean Chemical Engineering Research, volume 32, issue 3, 1994, Pages 402~402
The reduction of NO by hydrocarbons such as
, has been investigated over mordenite type zeolite catalysts. HM, CuHM, NZA, and CuNZA were prepared by ion-exchange method and their
efficiency was examined in a continuous flow fixed-bed reactor. As a result of the activity test,
appeared to be the best reductant over HM and
over CuNZA. The reaction variables for
-CuNZA system have been examined for its optimal operating condition. NO conversion reaches about 94% by the feed of 2,000ppm of
. The highest conversion of NO was observed at 2.0% of
. NO conversion of CuNZA depends on the exchange level of copper ions on the catalyst structure. No deterioration of the catalytic activity for CuNZA was observed at above
even after 30 hours of on-stream time. Based upon the transient test of CuNZA catalyst with the shut-off of reactants,
might be a reaction intermediate.
formed in the reaction may play an important role for HM catalyst at the reaction temperature above
. It can be concluded that CuNZA is a highly active and promising catalyst for the reduction of NO with
. The reaction path of this catalytic system is the most important key for the high accomplishment of NO conversion.
Effects of Pressure Ratio, Feed Rate, and Purge Rate on PSA Performance
Suh, Sung-Sup ; Shin, Chee-Burm ;
Korean Chemical Engineering Research, volume 32, issue 3, 1994, Pages 414~414
Pressure swing adsorption process for oxygen production from air was studied by numerical simulation to estimate product purity, recovery, and productivity. At a fixed feed rate, maximum purity exists. In case of large feed velocity and pressure ratio, purity increases, then decreases as purge-to-feed ratio increases. Feasible region could be found in a figure showing recovery versus purity with fixed pressure ratio. From this figure, maximum recovery could be obtained for a given purity. Maximum productivity for a given purity was obtained at different operating conditions. As pressure ratio increases above 5, recovery hardly changes and productivity increases considerably.
Characteristics of Solid Solubilities of Methoxyphenylacetic Acid Isomer Mixture in Supercritical Carbon Dioxide
Lee, Hyung-Keun ; Kim, Choon-Ho ; Choi, Cheong-Song ;
Korean Chemical Engineering Research, volume 32, issue 3, 1994, Pages 425~425
A supercritical fluid extraction system which employed microsampling technique and flow type was built and solubility data for mixture of o-methoxyphenylacetic acid(MPA) with m-, p-MPA in supercritical carbon dioxide were obtained at 308.2K, over a pressure range 11 to 34 MPa. The ternary solubility was higher than that of binary system, and solubility enhancement factor was increased with density, and a solubility of a given solid in the ternary system was increased relative to that in the binary system in proportion to the solubility of the other solid in carbon dioxide. But selectivity in ternary system became lower than that in binary system. The solubility enhancement factor was expressed as a function of the density of pure carbon dioxide, and a good linear relationship was observed for this system.
Simulation of Plasma Etch Profile based on a Model of Elastic Collision between Ions and Neutrals
Han, Jae-Hyun ; Cho, Byeong-Ok ; Chung, Chan-Hwa ; Moon, Sang-Heup ;
Korean Chemical Engineering Research, volume 32, issue 3, 1994, Pages 431~431
Profiles of narrow and deep trenches produced by plasma ion etching have been simulated by a Monte Carlo method based on simple collision model. In the plasma etching process, ions from the bulk plasma are introduced into the sheath layer to be accelerated by the electric field toward the electrode plate. A substrate on the electrode plate is etched by the incident ions, whose kinetic energy and travelling direction are modified by random collisions with the neutrals in the sheath. We have simulated the ion etching process assuming an elastic collision between the ions and the neutrals in the sheath layer. Distribution functions for the ion energy and its arrival angel at the substrate surface have been obtained, and they have been used for computation of the time-dependent etch profile of the substrate by string algorithm. Profile of the etched trench has higher aspect ratio when the ratio between the mean free path of the ion and the thickness of the sheath layer(MFP/Sh) is larger. The etch rate decreases as the MFP/Sh ratio becomes smaller and the mask width narrower, which agrees with the experimental observations. The socalled "dove tail"(or "trenching") shape observed at the bottom corner of the etched trench may be simulated successfully by considering the ions glancing from the side wall after collision at low angles.
The Effects of Alcohols in Substrate on the Biosynthesis of PHB and P(HB-co-HV)
Kim, Bum-Sang ; Cho, Geun-Do ; Oh, Joon-Taek ; Kim, Woo-Sik ;
Korean Chemical Engineering Research, volume 32, issue 3, 1994, Pages 441~441
This study is concerned with the synthesis and the properties of PHB and P (HB-co-HV) copolymer in Alcaligenes eutrophus NCIB 11599 using glucose and alcohol as carbon sources. Alcohols such as methanol, ethanol, propanol, butanol and pentanol were used as carbon sources. When less than 0.4g/L alcohol with 10g/L glucose was added as a carbon source with glucose, the specific growth rate and the polymer accumulation rate were improved compared with using only glucose as a carbon source. The specific growth rate was increased to a maximum of 12% and 20% in ethanol and pentanol added substrate respectively. The polymer accumulation rate was increased to a maximum of 40% and 36% in ethanol and pentanol added substrate. P(HB-co-HV) copolymer was obtained when propanol or pentanol was used as a substrate with glucose. The HV fraction in copolymer was increased according to the increase of alcohol concentration in substrate. The melting temperature of copolymer synthesized by propanol or pentanol was decreased according to the increase of alcohol concentration. When propanol was used as a substrate, the melting temperature of copolymer was decreased to
. On the other hand, the melting temperature of polymer synthesized by methanol, ethanol or butanol added substrate was constant at
, the melting temperature of PHB.
Surface Renewal Model of Gas Absorption with Instantaneous Irreversible Reaction in Aqueous Slurry
Park, Sang-Wook ; Suh, Dong-Soo ; Park, Moon-Ki ; Kim, Sung-Soo ; Kumazawa, Hidehiro ;
Korean Chemical Engineering Research, volume 32, issue 3, 1994, Pages 448~448
The absorption of carbon dioxide into aqueous slurry was carried out using a stirred absorber in the presence of solid particles such as
and 1 atm. The reaction between dissolved carbon dioxide and
in a slurry was an instantaneous irreversible reaction. The absorption rate in solid suspension containing fine particles smaller than the liquid film thickness was considerably higher than the rate in a saturated solution containing large particles. It was explained by the fact that the dissolution of solid was enhanced by the reaction between the absorbed gas and the dissolved solid species in the liquid film. The enhancement factor could be explained by the surface renewal theory and was compared with those by the film theory and the penetration theory.
Side-Chain Alkylation of Toluene with Methanol over Basic Zeolites
Lee, Tae-Jin ; Kim, Heon-Deog ; Chang, Won-Chul ;
Korean Chemical Engineering Research, volume 32, issue 3, 1994, Pages 456~456
Catalytic alkylation of toluene with methanol was studied at atmospheric pressure,
, and toluene/methanol feed molar ratios of 2-6 in a fixed bed reactor. Catalysts were prepared from the commercial X-type zeolite by ion exchange with alkali cations and/or impregnation of
. The yield of xylenes decreased in the catalyst sequence NaX>Na-cluster X>KX; the reverse tendency was found for the yield of styrene and ethylbenzene. These results suggest that benzene ring alkylation and side-chain alkylation depend on the catalyst acidity and basicity, respectively. The distributions of the acidity and basicity were also investigated by differential scanning calorimetry(DSC) and correlated with the performance of the catalysts. It was thought that a surface acid property as well as a surface base property played an important role in the course of the reaction.
Drying characteristics of PVC Resin in an Inert Medium Fluidized Bed
Lee, Dong-Hyun ; Kim, Sang-Done ;
Korean Chemical Engineering Research, volume 32, issue 3, 1994, Pages 463~463
The effects of the inlet gas temperature(
), the gas velocity(0.32-0.67m/s) and the feed rate of PVC resin(0.048-0.192kg/hr) on the drying efficiency have been determined in a 0.083m-ID 1.2m-high stainless steel column. The drying efficiency in an inert medium fluidized bed increases with increasing the feed rate of PVC resin, but it decreases with increasing the inlet gas temperature and gas velocity. The drying efficiency increases with increasing the mass loading which is the mass ratio of inlet gas to the dried PVC resin from the bed. The drying efficiency of PVC resin in an inert medium fluidized be has been correlated with the mass loading and Kossovich Number.
Effects of Synthesis Conditions on Physical Properties of
-Alumina Made from Al-alkoxide Precursors
Baek, Eun-Joo ; Nam, Young-Woo ;
Korean Chemical Engineering Research, volume 32, issue 3, 1994, Pages 469~469
Al-alkoxides were prepared and hydrolyzed by sol-gel method to get Al-hydroxides. Al-hydroxides were calcined to form
-alumina. The effects of alkyl groups of Al-alkoxide prepared from different alcohols on the properties of
-alumina were observed. The effect of hydrolysis conditions on the specific surface area and pore volume of
-alumina were examined with varing the contents of benzene, water and HCl.
Gaseous Adsorption Properties of n-Hexane, Methylethylketone and Toluene on Granular Activated Carbon
Park, Jun-Taik ; Kim, Jong-Sik ; Chung, Kyeong-Hwan ; Moon, Hee ; Seo, Gon ;
Korean Chemical Engineering Research, volume 32, issue 3, 1994, Pages 476~476
Adsorption of n-hexane, methylethylketone and toluene on a granular activated carbon was studied. At
adsorption isotherms of each component were measured by a gravimetric apparatus, and they were fitted by Freundlich equation. Adsorption breakthrough curves of individual components and binary mixtures were measured in a flow adsorption apparatus. Binary breakthrough curves could be nicely simulated by an ideal adsorption solution theory based on adsorption isotherms of single-component systems.
Comparison of the Precipitate Flotation and the Adsorbing Colloid Flotation on the Removal of Cr(VI) from Aqueous Solution
Kang, Sung-Gil ; Choi, Sang-June ;
Korean Chemical Engineering Research, volume 32, issue 3, 1994, Pages 483~483
Experimental investigations on the removal of Cr(VI) from aqueous solution were carried out by the foam separation techniques (precipitate and adsorbing colloid flotation) using sodium lauryl sulfate as a collector. The optimum pH for the removal of Cr(VI) was found to be about 8 for precipitate flotation and about 4 for adsorbing colloid flotation with
. The effect of surfactant and foreign ions(
) addition on the removal efficiency were observed. The adsorption and separation mechanism on the removal of Cu(II) ion by the foam separation techniques of precipitate and adsorbing colloid flotation were also observed.
Particle Entrainment in a Fluidized Bed with Secondary Air Injection
Choi, Jeong-Hoo ; Kim, Kyu-Jong ; Kim, Peter ;
Korean Chemical Engineering Research, volume 32, issue 3, 1994, Pages 489~489
The particle entrainment rate was measured and discussed in a cold model fluidized bed(0.1m-ID, 2.4m-height) which employed a secondary air injection at a height of 0.2m above the distributor plate. Sand particles of mixed sizes under 0.5mm in screen size were used as bed materials. The particle size(0.128-0.363mm), the overall superficial gas velocity(0.76-2.77m/s), the secondary air fraction(0-0.5), and the static bed height(0.1-0.3m) were considered as experimental variables. The entrainment rate increased with the gas velocity, but with a decrease of particle size. The effect of static bed height was negligible. The entrainment rate decreased with an increase of the proportion of secondary air. The effect of secondary air fraction was appreciable for over-bed injection and was reduced as the location of second gas inlet moved toward in-bed.
The Effect of Operating Variables of MCFC on the Single Cell Performance
Lim, Tae-Hoon ; Lee, Kab-Soo ; Nam, Suk-Woo ; Oh, In-Hwan ; Hong, Seong-Ahn ; Lim, Hee-Chun ;
Korean Chemical Engineering Research, volume 32, issue 3, 1994, Pages 498~498
To establish the operating conditions of molten carbonate fuel cells, the relationship between operating variables and the performance of the single cell with the active electrode area of
was investigated. The single cell showed the open circuit voltage of 1.13V and the cell voltage over 0.9V at the current density of
. The performance decreased with the increase of the hydrogen utilization, while the effect of the oxygen utilization turned out to be negligible. The performance increased proportionally to the hydrogen partial pressure of the anode gas, but the highest performance was obtained at the cathode gas composition of 33% oxygen and 67% carbon dioxide which is the stoichiometric condition, Humidification of the anode stream to prevent carbon deposition dropped the cell voltage as much as the voltage loss estimated from the Nernst equation, and the oxygen gain was 50mV and 90mV at the condition of the open circuit voltage and at the current density of
, respectively. The cell voltage at the given conditions tended to increase with the increase of the operating temperature, but the increasing rate became smaller above
Effect of Ferric Oxide on the Oxidative Regeneration of Sulfided
Lee, Young-Soo ; Yoo, Kyong-Ok ;
Korean Chemical Engineering Research, volume 32, issue 3, 1994, Pages 506~506
The oxidative regeneration over
mixed metal oxide sorbent sulfided by
was investigated. Complete regeneration was occurred on all the sulfided sorbents containing
except pure ZnS. XRD diagram of regenerated sorbents was similar to that of fresh sorbents. Zinc sulfate reported to be generated during the oxidative regeneration was not detected. On the basis of
uptake curve and the time required for complete regeneration, we concluded that the amount of
added did not affect the oxidative regeneration.