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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
Prediction of Solubility of Abietic Acid in Cleaning Solvent
Row, Kyung-Ho ; Lee, Youn-Yong ;
Korean Chemical Engineering Research, volume 31, issue 6, 1993, Pages 623~623
According to the Montreal Protocol, CFC 113(1,1,2-trichloro 1,2,2-trifluoroethane), one of the ozone-depleting substances, will be prohibited to use as a cleaning solvent essentially in the electronic industry. Therefore, the development of the alternative cleaning solvents to CFC 113 is being accelerated. As one of the min characteristics of solvents, the solubility is theoretically calculated using the activity coefficient of solute from Scatchard-Hildebrand relation and the solubility parameters. Abietic acid is a major constituent of the rosin-based flux used for PCB sodering, and is designated as a contaminant. The cleaning solvents used in this work include water, acetonitrile, methanol, IPA, acetone, d-limonene, trichloroethylene, 1,1,1-trichloroethane, chloroform, methylene chloride, carbon tetrachloride, perchloroethylene as well as CFC 113. By use of a non-linear regression technique, the mole fraction solubilities are calculated and the heat of fusion of abietic acid is found to be 8831cal/g-mol. The results show that for the polar solvents(water, acetonitrile and methanol), the mole fraction solubility can not be calculated using the Scatchard-Hildebrand relation, but for the other nonpolar solvents, the agreements between the calculated and the experimental solubilities are relatively good.
Flow and Axial Mixing Characteristics of Liquid Phase in a Packed Column with Gas-Liquid Cocurrent Downflow
Cho, Ji-Hoon ; Sung, Ki-Chun ; Kim, Tae-Ok ;
Korean Chemical Engineering Research, volume 31, issue 6, 1993, Pages 628~628
For downward cocurrent gas-liquid flow in a packed column, the flow and axial mixing characteristics of liquid phase were investigated. Based on experimental residence time distributions of liquid phase, parameters of mixing models were evaluated with three proposed mixing models : The axial dispersion model(ADM), the plug flow model with stagnant zone(PFM), and the axial dispersion model with stagnant zone(DSM). Accordingly, the applicability and parameters of each mixing model were analyzed for various operating conditions. we found that the flow and mixing characteristics of liquid phase could be analyzed well by DSM, and also that the flow characteristics in the dynamic zone tended to access the plug flow at higher liquid Reynolds
. Also, the fraction of stagnant zone estimated by the curve fitting method for the case of DSM was less than that of PFM. As liquid velocity increased, the fraction of the stagnant zone was decreased while the mass transfer coefficient between the dynamic and the stagnant zone was increased. In the dynamic zone, the calculated Peclet numbers in both ADM and DSM were increased with increasing the diameter of glass bead as a packing material and increasing liquid velocity at $Re_L>40$. In these conditions, correlations of these parameters were obtained for various operating conditions.
Solubilities of Phenol and its Chlorinates in supercritical Carbon Dioxide
Bae, Hyo-Kwang ; Jeon, Jeong-Ho ;
Korean Chemical Engineering Research, volume 31, issue 6, 1993, Pages 637~637
The solubilities of phenol, p-chlorophenol, 2,4-dichlorophenol, 2,6-dichlorophenol and 2,4,6-trichlorophenol in carbon dioxide were measured under the supercritical conditions of pressure range between 8 and 20MPa, and 309.2K, 318.2K and 333.2K, using the flow-type apparatus that was newly manufactured. The solubilities were good agreement with the equilibrium data predicted by using Peng-Robinson equation of state, although temperature of a and b in the equation of state were obtained by regression method utilizing the experimental solubilities and they and little affected by the temperature for a binary system. The enhancement factor obtained from the solubility data was linearly related in semi-log plot, and the relations were affected by the temperature of a binary system.
Development of an Expert System for Functional Group Analysis in Group Contribution Method
Lee, Kun-Hong ; Yang, Gi-Joo ; Jung, June-Young ; Lee, In-Beum ;
Korean Chemical Engineering Research, volume 31, issue 6, 1993, Pages 647~647
A computer program which gave a functional group set from a given chemical formular was developed. this program has the form of a rule-based expert system, using the common LISP. The inference engine was developed using the forward chaining technique, and the knowledge base was composed of 80meta rules, 34 select rules and 7 combine rules. The functional groups were chosen following the Joback group contribution method, and the functional group sets were successfully obtained for the substances of less than 8 groups.
Preparation of Titanium Modified Mordenite and its Catalytic Properties in the Reaction of Benzene or Saturated Hydrocarbons with
Kim, Geon-Joong ; Cho, Byung-Rin ;
Korean Chemical Engineering Research, volume 31, issue 6, 1993, Pages 658~658
Titanium modified mordenites have been prepared hydrothermally or by subsequent reaction with titaniumtetrachloride vapour at elevated temperature after dealumination of H-mordenite. Incorporation of titanium into the mordenite type framework has been demonstrated by XRD, FT-IR,
MAS NMR analysis, and the catalytic benzene hydroxylation or n-hexane oxidation was used for checking the properties of Ti modified mordenite. Pure titania powder and
or H-mordenite showed no catalytic activity at all for these reactions, but titanium modified mordenite had activities in both reactions. the catalytic activity strongly depended on the kind of solvents, and the higher conversion of benzene or n-hexane was obtained with methanol solvent.
Methane Combustion on Transition Metal Oxide Impregnated La/Al Oxide Catalysts
Suh, Jeong-Kwon ; Ha, Baik-Hyon ; Koh, Jae-Cheon ; Lee, Jung-Min ;
Korean Chemical Engineering Research, volume 31, issue 6, 1993, Pages 667~667
Combustion catalysts were prepared by the impregnation of transition metal oxide on La/Al
, and then calcined in air. Methane combustion was carried out using these catalysts. X-ray diffraction analysis indicates that La/Al oxide was crystallized from amorphous form into
. Crystallization was accelerated by the addition of copper on La/Al oxide, but it was retarded by the addition of chromium on La/Al oxide. The copper content of the surface of CuO-La/Al oxide decreased as the calcination temperature increased. This result indicates the formation of solid solution. In case of
mainly existed on the catalyst surface. The activities of catalysts calcined at
appeared as the following order; CuO, $Cr_2O_3>Fe_2O_3>MnO>CoO>NiO$. The catalytic activity of CuO-La/Al oxide decreased as the calcination temperature increased. However the catlytic activity of
oxide was still maintained after calcination at
Dry Etching of Tungsten Films in
Kwon, Sung-Ku ; Nam, Chul-Woo ; Woo, Seong-Il ;
Korean Chemical Engineering Research, volume 31, issue 6, 1993, Pages 675~675
Dry etching of LPCVD tungsten film was performed using
plasma in both reactive ion etching(RIE) and plasma etching(PE) modes. The etch rate of tungsten and the selectivity of tungsten to
were examined as a function of oxygen content in feed gas, pressure and RF power. The maximum etch rate in PE and RIE modes were observed at 40 and 50%
in feed gas, respectively. The maximum selectivities of tungsten to
in both modes were about 16 and 2.3, respectively. Mass spectroscopy(MS) and optical emission spectroscopy (OES) were used to identify the reactive species in
plasma. The results of MS and OES analyses in measuring the etch rate as a function of
percent suggest that
are main etch products for tungsten etching. The maximum etch rate was obtained at 0.6 torr for PE mode and 200 mtorr for RIE mode. With the increase of RF power, the etch rates of both tungsten and
increased, but the selectivity of tungsten to
A Study of the Catalytic Characteristics and the Activities of
Hydrocarbon Partial Oxidations in Vanadium Based Crystalline Glasses
Lee, In-Wha ; Jung, Ji-Hoon ; Hong, Suk-In ;
Korean Chemical Engineering Research, volume 31, issue 6, 1993, Pages 683~683
Vanadium crystalline glasses were prepared and investigated through surface area measurement, X-ray diffraction, chemical analysis and catalytic oxidation as a probe reaction. The vanadium based glasses were prepared by fusing
mixtures with different compositions and annealling conditions. The prepared glasses were leached in acidic solution, dried and calcined sequentially. From the results of surface area analysis and chemical analysis of
ratio, it was found that the glasses were porous materials of which surface area is about
in binary system and
in ternary system. The
ratio increased with
ginary glass. X-ray diffraction analysis showed that the fresh glass was amorphous but it changed to crystalline as it was annealled. Through the catalytic oxidation of methylcyclopentane, cyclopentane and cyclopentadiene, catalytic activity and selectivity of maleic-anhydride on vanadium based glasses were studied. As to geometric and chemical difference between
systems, the reaction showed also different results. Binary catalysts had less than 10% yield of maleic anhydride, but ternary catalysts had maximum 50% yield of maleic anhydride for cyclopentadiene.
Adsorption Equilibrium of CO and
on Activated Carbon Impregnated with Cuprous Chloride
Min, Byoung-Moo ; Shon, Hyun-Sik ; Kim, Sung-Hyun ; Yoo, Ki-Pung ;
Korean Chemical Engineering Research, volume 31, issue 6, 1993, Pages 693~693
Activated carbons impregnated with cuprous chloride were prepared to separate carbon monoxide from gas mixture. Adsorption equilibrium experiments were performed for carbon monoxide and carbon dioxide. From these experimental results, adsorption equilibrium isotherms were obtained for each adsorption system. Each adsorption systems can be represented by FH-VSM adsorption equations with the parameters obtained from the experimental result. Amount of carbon monoxide adsorbed on adsorbents increased with impregnation concentration of cuprous chloride on activated carbon up to 37wt%, but decreased above impregnation concentration of 37%. These adsorbents which show good reappearance of adsorption in recycling experiments could be used for a TSA process.
Separation of Dimethylethylbenzene from
Naphtha Cracking Raffinate by Adductive Crystallization Using Thiourea
Kim, Kwang-Joo ; Lee, Choul-Ho ;
Korean Chemical Engineering Research, volume 31, issue 6, 1993, Pages 701~701
The separation of dimethylethylbenzene(DMEB) from the
raffinate found in the process of ethylene production by the pyrolysis of naphtha was studied using adductive crystallization with thiourea. The effect of thiourea adduction were investigated on the inductors, solvent of thiourea and adduction temperature. DMEB could be separated by multistage adductive crystallization from
, raffinate as a high purity. The most effective material of the inductor investigated in this study was 1,2,4-trichlorobenzene. The selectivity of solvents in thiourea adduction depended on the polarity of solvents(alcohols), and the most effective solvent of those was methanol.
Preparation and Adsorption Characteristics of Activated Carbon from Korean Rice Hull
Ko, Yong-Sig ; Ahn, Wha-Seung ;
Korean Chemical Engineering Research, volume 31, issue 6, 1993, Pages 707~707
A study was conducted to make activated carbon adsorbents using local rice hull ashes. As the carbonization temperature of the rice hull was increased, the specific surface area of the char increased steadily. The specific surface area of the char was enhanced either by boiling water washing, or by silica leaching using sodium hydroxide. When sodium hydroxide was used to leach out silica from the char, the specific surface area and the amount of silica removed increased most when the sodium hydroxide leaching was conducted in several stages. Activated carbon was also prepared from the rice hull by chemical activation method using phosphoric acid. The adsorption characteristics of phenol onto the activated carbons prepared were measured in a batch reactor. These results showed that as the specific surface areas of the activated carbons increased, better adsorptivities to phenol were obtained. The relationship between the amount of phenol adsorbed and equilibrium concentration was found to be well represented by the Freundlich isotherm. The adsorption capacity of the activated carbon prepared through chemical activation method was slightly better than that of the commercial product of Calgon F300.
Acetonitrile Sensing Characteristics of
Sohn, Jong-Rack ; Cho, Sung-Guk ; Park, Hyo-Derk ; Lee, Duk-Dong ;
Korean Chemical Engineering Research, volume 31, issue 6, 1993, Pages 715~715
thick film sensor was fabricated by means of screen printing method. The sensing characteristics of acetonitrile was influenced by the chemical species produced by the oxidation reaction of acetonitrile on the surface of metal oxide. From the result of observed infrared spectra, the products formed by the oxidation reaction of acetonitrile were found to be mainly
, which influenced the sensing properties. The
sensor added with
exhibited the sensitivity of 94% at the operation temperature of
and showed higher selectivity to acetonitrile than to CO,
. The thick film sensor which maintained for 30 days at the operation temperature
exhibited the resistance of
and sensitivity of 84% in 85ppm of acetonitrile.
Preparation of Polyurea Fine Particles Using Aerosol Reactor
Kim, Sung-Ik ; Kim, Sun-Geon ;
Korean Chemical Engineering Research, volume 31, issue 6, 1993, Pages 723~723
Spherical polymer particles with narrow size distribution have been prepared by aerosol-phase polymerization. The polyurea particles were prepared by the reaction of TDI(toluene-2,4-diisocyanate) or HDI(hexamethylene diisocyanate) droplets with EDA(ethylene diamine) vapor. The use of seed(NaCl) nuclei helped the polymer particles smaller in size and made the size distribution of the particles narrower. The particle size increased substantially with boiler temperature and decreased slightly with increasing the carrier gas flow rate. Increase in reboiler temperature improved the monodispersity of the particle size. Sphericity and surface smoothness of the particles were improved by decreasing particle size and controlling the reaction rates. The coating of
on the surface of the prepared polymer particles was carried out by condensing
on the particle surface and subsequently reacting the liquid film with water vapor. The reaction system was also applied to prepare polyamide particles successfully.
Operational Characteristics of Single Cell in Phosphoric Acid Fuel Cell
Song, Rak-Hyun ; Kim, Chang-Soo ; Choi, Byung-Woo ; Shin, Dong-Ryul ; Choi, Soo-Hyun ;
Korean Chemical Engineering Research, volume 31, issue 6, 1993, Pages 735~735
Operational characteristics of single cell in phosphoric acid fuel cell(PAFC) have been studied using oxygen gain and AC impedance methods. Also effect of reactant gas starvation on PAFC performance was examined. The single cell was operated for 4,500 hr at the average performance decay rate of 19.7 mV/1,000 hr. At the operation time below 1,000 hr the activation process was dominant over the cell electrode reaction and then the decreased cell performance is due mainly to an increased internal resistance of the cell and an increased interfacial resistance of the oxygen electrode. At the operation time above 2,000hr, the oxygen gain was larger than a theoretical value of the activation-diffusion mixed process, which indicates that the cell decay at long run resulted from the slow diffusion process. In addition the hydrogen starvation showed more cell performance loss than the oxygen starvation due probably to carbon corrosion. These results were discussed as related to the oxygen electrode reaction at three phase boundary of the electrode and the degradation of the electrode components.
Modification of the Joback Group Contribution Method Using Artificial Neural Networks
Lee, Kun-Hong ; Jung, June-Young ; Lee, In-Beum ;
Korean Chemical Engineering Research, volume 31, issue 6, 1993, Pages 744~744
Using the technique of artificial intelligence, the general method to improve the accuracy of Group Contribution Methods was proposed. The Joback GCM was chosen and the back propagation neural networks were trained 30000 to 40000 times with the experimental data of more than 400pure substances. The estimations of the critical properties, the normal boiling and the freezing temperatures, heats of formation, Gibbs free energies of formation, and ideal gas state heat capacities using trained weight matrices were much better than those from the conventional GCM developed on the basis of an assumed mathematical model.
Effect of Ferric Oxide on the Adsorbent for Hydrogen Sulfide
Lee, Young-Soo ; Yoo, Kyong-Ok ;
Korean Chemical Engineering Research, volume 31, issue 6, 1993, Pages 753~753
The removal of hydrogen sulfide over
mixed metal oxide sorbents was investigated.
and X-ray diffraction(XRD) were used to identify the reduction behavior and crystallographic structure of sorbent, respectively. When ferric oxide was added to the zinc oxide phase, double phase crystallographic structure change was occurred and hydrogen consumption(HC) for the sorbent reduction was increased. Furthermore the reduction of ZnO was retarded because of this structural change. We found that zinc ferrite phase with spinel structure yielded high
removal capacity and
added promoted the formation of
during the sulfidation. It was found that the amount of hydrogen resulted from the decomposition of
in the presence of metal sulfides was increased as ferric oxide was increased.
Liquid-liquid Equilibria of Water-nonionic Surfactant and Extraction of o-Chlorophenol Using Liquid Coacervate
Lee, Hyun-Song ; Lee, Huen ;
Korean Chemical Engineering Research, volume 31, issue 6, 1993, Pages 759~759
Liquid-liquid equilibria(LLE) was measured at pressures of 1 atm, 5, 10 and 15 MPa for the binary system of water and Triton X-100, which is known as a nonionic biological surfactant. The LCST of this binary system was found to be about
at all pressure investigated in this study. Tertiary LLE were also measured with addition of o-chlorophenol. Considerable amount of o-chlorophenol was selectively concentrated in the coacervate phase having nonionic surfactant in large excess. The partition ratio between two phases for this tertiary system increased up to 110. The Brij30,
aqueous solutions showed similiar trends as an Triton X-100 aqueous solution and the corresponding partition ratios were 200, 200 and 290, respectively. The experimental LLE data of the Triton X-100 and water binary system were compared with the predicted values calculated from the Flory-Huggins equation. The interaction energy parameter,
existing in the Flory-Huggins equation was experessed as a function of temperature using two adjustable parameters.
Thermal Decomposition and Reduction of Ammonium Uranate
Kim, Eung-Ho ; Kwon, Sang-Woon ; Jeong, Ji-Young ; Park, Jin-Ho ; Hwang, Sung-Tai ; Chang, In-Soon ; Choi, Cheong-Song ;
Korean Chemical Engineering Research, volume 31, issue 6, 1993, Pages 767~767
Ammonium uranate(AU), prepared by the reaction of
, was thermally decomposed and reduced in a TG-DTA unit in nitrogen and hydrogen atmospheres. Various inter-mediated phases produced during the thermal decomposition and reduction processes of AU have been investigated by X-ray analysis and infrared spectroscope. It was found that AU was a mixture of AU II and AU III classified by Cordfunke, and thermally decomposed in both nitrogen and hydrogen atmospheres as the following mechanism :
. In the hydrogen atmosphere,
was converted into
phase. The obtained results were compared with the published data, and the effect of nitrate ion on the thermal decomposition AU was determined in the present study.
Formation of Thin Film by Chemical Aerosol Deposition
Kim, Kyum-Dong ; Lee, Soo-Keun ; Kim, Sun-Geon ;
Korean Chemical Engineering Research, volume 31, issue 6, 1993, Pages 776~776
film by chemical aerosol deposition(CAD) has been investigated experimentally and theoretically. The carrier gas Flow rate, the nozzle-to-substrate distance and the substrate temperature were chosen as major process variables and the experimental work has been carried out to find their effects on the deposition efficiency, the film thickness and its distribution. Both the deposition efficiency and the film thickness increased with the carrier gas flow rate and the substrate temperature but decreased with the nozzle-to substrate distance. Especially at higher rate of the film deposition, the central part of the film had a concave surface like a valley. The flow and the temperature fields of the fluid phase in the region between the nozzle and the substrate were calculated numerically. The the particle trajectories and their evaporation were also simulated numerically from the equations of both particle motion and evaporation. As a result, the evaporation of the liquid particles was to occur abruptly so that the liquid-phase region had a clear boundary. The extent of the region was found to be a determining factor in the film deposition, which characterizes the chemical aerosol deposition.
Ethanol Production Using Membrane-Encapsulated Yeast
Cheong, Soo-Hwan ; Park, Joong-Kon ; Chang, Ho-Nam ;
Korean Chemical Engineering Research, volume 31, issue 6, 1993, Pages 788~788
An encapsulation method in which yeast cells were immobilized in calcium alginate capsule was investigated. The calcium alginate capsule could burst because of carbon dioxide gas produced during ethanol fermentation. A new method for preparing calcium alginate microcapsules was developed and it was observed that gas transfer was further facilitated about two times as fast as in conventional capsule membrane. By adding a small amount of calcium chloride in the medium it was possible to control the swelling of the microcapsules and increase the dry cell density to 310g/l. The rate of ethanol production of the system was nearly the same as that of bead system in continuous operation. For the calcium alginate capsule without adding surfactant, it was possible to increase the gas transfer rate about 20 times by lowering the dry cell density of the capsule to about 74g/l. This was possible because of thin wall thickness and expanded surface area of the capsule.
A Study on the Extraction of Heavy Hydrocarbon Oil from Atmospheric Residues Using Solvent of Supercritical n-Pentane
Baek, Il-Hyun ; Kim, Choon-Ho ; Kim, Sung-Hyun ; Kim, Young-Il ; Hong, Sung-Sun ;
Korean Chemical Engineering Research, volume 31, issue 6, 1993, Pages 796~796
Supercritical extraction of residual oil was performed using n-pentane as a supercritical solvent. The amount of asphaltene, metal complex and sulfur contents of extracted oil as well as the oil-extraction yield were investigated during this experiment. Oil-extraction yield was increased as the system pressure was increased and the temperature was approached to the critical temperature of n-pentane. The metal complex content of extracted oil was much decreased when compared with that of residual oil, however, the sulfur content of extracted oil was slightly decreased when compared with that of residual oil.
Matrix Effect on Gas Chromatographic Analysis with Flame Ionization Detector
Park, Byung-Eon ; Kim, Han-Soo ; Park, Doo-Seon ; Son, Moo-Ryong ;
Korean Chemical Engineering Research, volume 31, issue 6, 1993, Pages 804~804
The matrix effect of balance gases on gas chromatographic analysis with FID(Flame Ionization Detector)was investigated. It was well known that the inorganic gases such as He,
, Ar and
gave little or no response in the FID, but it gave a noticeable response according to the chosen carrier gas. When the carrier gas was the same as the balance, no matrix effect was found. But when the balance gas had any above mentioned gas as a different component from the carrier gas, even if the concentration of component was a small amount(about 5%), the matrix effect appeared. The effect decreased as follows : $O_2>H_2>He>Ar>N_2$. In the case of
, the effect was quite large because of using
(or air) and
for the flame of the FID. When the balance gases were He, Ar and
, also the matrix effect appeared due to the change of the environment of detector by the introduction of those balance gases. Form this experiment, it is better to choose the same carrier gas with the balance gas component in the pure gas analysis. If the balance gas is not the same as the carrier gas, it should be expected that the matrix effect will appear. And also, with mixed gas analysis, the matrix effect will be certainly found, even if that mixed gas has just a few percent of the different component from the carrier gas.
Analysis of Mass Transfer Characteristics in Concentration Polarization Layer of Ultrafiltration[I] -Comparison of Osmotic Pressure Model and Boundary Layer Resistance Model-
Youm, Kyung-Ho ; Kim, Woo-Sik ;
Korean Chemical Engineering Research, volume 31, issue 6, 1993, Pages 813~813
On the basis of the macromolecular solution behavior in the concentration polarization layer formed on the membrane surface, the comparison of the osmotic pressure model and the boundary layer resistance model was investigated. The applicable ultrafiltration range was suggested to these two models respectively. The permeate flux and solute rejection during the ultrafiltration of macromolecular solutions such as PEG(
, similar to the cut-off of membrane) and dextran(
, higher than the cut-off of membrane) solutions were measured with polysulfone membranes(MWCO : 3,000). The osmotic pressure model was capable of predicting the complete ultrafiltration range obtained using low molecular weight (similar to the cut-off of membrane) and high molecular weight macromolecular solutions. Whereas the boundary layer resistance model was only capable of analyzing the ultrafiltration of high molecular weight macro-molecular solution, i.e., dextran which represented high concentration polarization modulus and solute rejection, and formated the semi-dilute solution behavior in the concentration polarization layer.
Improvement of Combustion Efficiency of Fine Particles by the Granulation in a Fluidized Bed Combustor
Cha, Wang-Suk ; Kim, Sung-Hyun ; Hong, Sung-Chang ; Oh, Kwang-Joong ; Doh, Dong-Sup ;
Korean Chemical Engineering Research, volume 31, issue 6, 1993, Pages 824~824
Granulation experiment was carried out in a 0.109 m ID, 1.8 m height fluidized bed combustor of the multi-sized particles. Granulation of fine coal particles and fluidizing characteristics were investigated by the pressure fluctuations, combustion efficiency, temperature profile and mean particle diameter. Granulation mechanism was studied by the SEM analysis. Defluidization occurred in the mixed firing of salt and anthracite coal and the information on the information on the defluidization phenomena was interpreted with the pressure fluctuation signals and temperature profile. It was found that the combustion efficiency in the elutriated stream was increased 3-4 times by the granulation of fine coal particles and that the granulation mechanism was agglomeration model.
Hydrogenation of CFC-114a over Palladium Catalysts
Kim, Do-Woan ; Ihm, Son-Ki ; Park, Kun-You ; Lee, Byung-Gwon ;
Korean Chemical Engineering Research, volume 31, issue 6, 1993, Pages 831~831
The effects of supports and 1B group metal addition have been investigated in a hydrogenation of CFC-114a. Among the supports, alumina and titania supported palladium catalysts showed higher activity and selectivity for HFC-134a than those on active carbon and silica supports. The reactivity patterns are in good correlation with the amount of strongly adsorbed CFC reactant, as evidenced by the TPD experiments. Bimetallic catalysts(palladium and 1B metal; Au and Ag) supported on alumina showed some increase in activity and selectivity. It is presumed from hydrogen chemisorption, TPD and EXAFS that the role of 1B metals is to increase the dispersion of palladium crystallites.
Sohn, Jong-Rack ; Pae, Young-Il ; Cho, Sung-Guk ;
Korean Chemical Engineering Research, volume 31, issue 6, 1993, Pages 838~838
catalysts were prepared by dry impregnation of powdered
with an aqueous solution of
followed by calcining in air, and
catalysts were prepared by modifying impregnated
followed by calcining in air. The characterization of prepared catalysts was performed by using FTIR, DSC-TGA, and XRD, and by the measurement of surface area. The addition of
and modification with
shifted the phase transition of
from amorphous to tetragonal and from tetragonal to monoclinic to higher temperatures due to the interaction between
was dispersed on the surface of
up to 10mol% of
, any crystal phase of
even at the calcination temperature of
was not observed on the XRD patterns. However, in the case of sample containning 15mol% of
crystal phase appeared on XRD pattern from the calcination temperature of
Production of Fructo-oligosaccharides by the Mixed-enzyme System of Fructosyltransferase and Glucose Isomerase
Yun, Jong-Won ; Noh, Ji-Seon ; Lee, Min-Gyu ; Song, Seung-Koo ;
Korean Chemical Engineering Research, volume 31, issue 6, 1993, Pages 846~846
The production of fructo-oligosaccharides having new composition was investigated using the mixed-enzyme system of fructosyltransferase and glucose isomerase. Despite of decrease in glucose concentration which acts as an inhibitor of fructosyltransferase during the production of fructo-oligosaccharides, the concentration of fructo-oligosaccharides was not high due to the altered kinetic parameters in the mixed-enzyme system was proposed and compared with the experimental results, which showed good agreement with experimental data. Surprisingly, the
values and inhibition constant of
for fructosyltransferase in the mixed-enzyme system were different from those of fructosyltransferase alone. The fructose isomerized from glucose by glucose isomerase did not act as a sucrose acceptor, which meant the isomerized fructose did not play a part in the production of fructo-oligosaccharides.
A Study on the Optical Characteristics of Anthracite Coals
Park, Cheol-Woo ; Park, Suk-Whan ; Hyun, Ju-Soo ; Shon, Eung-Kwon ;
Korean Chemical Engineering Research, volume 31, issue 6, 1993, Pages 852~852
Maceral of coal and reflectance of vitrinite have been determined for the domestic and the imported coals. Also the relationship between chemical and optical properties of coal has been investigated. The maceral of coal samples is composed of both two varieties of collinite and vitrodetrinite in vitrinite group and three varieties of semifusinite, fusinite and inertodetrinite in inertinite group. Micrinite, gaphinite, mottlite and impregnite have been observed in the domestic coals. The degree of coalification for domestic coal is meta-anthracite and that of the imported coal is anthacite. As the macerals in vitrinite group is increased the amount of volatile matter and carbon increased. Also the amount of volatile matter and carbon decreased with increasing macerals in the inertinite group. As the maximum reflectance of vitrinite is increased both, the anisotropy and the carbon composition increased but, the volatile matter and hydrogen decreased.
Cyclic Voltammograms for the Electrodeposition of
on the Titanium Substrate and it's Performances
Kim, Jae-Kwan ; Lee, Chung-Young ; Nam, Chong-Woo ;
Korean Chemical Engineering Research, volume 31, issue 6, 1993, Pages 858~858
As a basic study on the electrodeposition of
with high oxygen overvoltage and less comsumption on a titanium substrate, the optimal electrodeposition conditions and electrode characteristics were investigated by cyclic voltammograms. It was observed that the electrodeposition condition was optimal at 1.0M
, and anode potential, 1.50-1.65V vs. SCE. The
electrodeposition reaction was the diffusion controlled reaction that the fast the electrodeposition rate, the larger the grains size and the higher the oxygen overvoltage. Among various acids and organic additives used in this experiment,
with a high oxygen overvoltage was electrodeposited when sodium lauryl sulfate was added in
supporting electrolyte. Electrode performance and durability for the electrolytic preparation of sodium perchlorate from sodium chlorate with using lead dioxide electrodes electrodeposited on a titanium madras at above optimal electrodeposition conditions have been investigated. It was ascertained that the
electrode electrodeposited by adding sodium lauryl sulfate in
supporting electrolyte have the highest current efficiency and durability.
Isothermal Vapor-Liquid Equilibria of
Kim, Chul-Ung ; Kim, Beom-Sik ; Koh, Jae-Cheon ; Lee, Jung-Min ;
Korean Chemical Engineering Research, volume 31, issue 6, 1993, Pages 868~868
Isothermal vapor-liquid equilibria have been measured for
using headspace gas chromatography. The obtained results were correlated to the Wilson, Van Larr, Margules, NRTL equations. These experimental vapor-liquid equilibrium data for binary system of methylchlorosilanes are presented as the basic data of separation process.