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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 42, Issue 6 - Dec 2004
Volume 42, Issue 5 - Oct 2004
Volume 42, Issue 4 - Aug 2004
Volume 42, Issue 3 - Jun 2004
Volume 42, Issue 2 - Apr 2004
Volume 42, Issue 1 - Feb 2004
Selecting the target year
Current Status and Future Trend of Thin Film Photovoltaic Technology
Park, Chin-Ho ; Seol, Ji-Youn ;
Korean Chemical Engineering Research, volume 42, issue 3, 2004, Pages 269~279
Photovoltaic devices directly convert solar energy into electrical energy. These devices are currently fabricated by using a variety of materials, among which the single-crystalline Si is most widely used. The single-crystalline Si solar cells, however, have inherent drawbacks and limitations, in which substantial cost reductions are required for large scale applications, and difficulties remain in new product development such as flexible solar cells. An alternative approach to overcome these limits of crystalline Si solar cells is to develop thin film solar cells. This paper addresses the current status of thin film photovoltaic technology and provides the outlook of future solar cells.
Estimation of Pyrolysis Kinetic Parameters of HDPE by using Peak Properties of DTG Curve
Jang, Eun-Suk ; Kim, Seung-Do ; Shin, Dae-Hyun ; Lee, Kyong-Hwan ;
Korean Chemical Engineering Research, volume 42, issue 3, 2004, Pages 280~287
This research was designed to determine the pyrolysis kinetic parameters of HDPE using Peak Property Method (PPM) which was recently developed. The properness of PPM was verified by comparing theoretical Derivative Thermogravimetry (DTG) curve with experimental one. The kinetic parameters derived from PPM was compared with those estimated from typical analysis methods and those reported by previous studies. The PPM was developed based on the assumption that a specific pyrolysis reaction would be characterized by three peak properties of DTG curve: peak temperature, peak height, and conversion at peak temperature. The activation energy, pre-exponential factor, and reaction order of HDPE pyrolysis reaction, respectively, were 251.92 kJ/mol,
, and 0.581, demonstrating good agreement with those estimated by DTG curve fitting method. The PPM simulates experimental DTG curve excellently and it was proved that the three peak properties of DTG curve would be enough to represent a unique thermal reaction. The pyrolysis kinetic parameters would be estimated easily but accurately by the PPM. However, the PPM is only applicable for a reaction which is represented by a conversion function of power law equation.
Pore Characteristics of
Activated Carbon Fibers
Ryu, Seung-Kon ; Eom, Sang-Yong ; Yim, Kwang-Soon ; D, Edie Dan ;
Korean Chemical Engineering Research, volume 42, issue 3, 2004, Pages 288~295
activated carbon fibers (ACFs) were prepared by carbonization and steam activation of the 0.17, 0.34, 0.5 wt%
oxidized pitch fibers and characterized the microporosity depending on the activation conditions. The burn-off of the
carbon fiber was accelerated by the catalytic oxidation of
to carbon. When the carbon fiber contained 0.5 wt%
, the activation energy of carbon fiber decreased from 194 kJ/mole to 140 kJ/mole, the specific surface area was reduced from
, while the average pore size increased from
due to this catalytic oxidation. The average pore size can be far enlarged by increasing the
particle was confirmed to anatase and homogeneously distributed throughout the activated carbon fibers.
The Effect of Organic Solvent in Supercritical
+ Water Microemulsion with Sodium Salt of Bis(2,2,3,3,4,4,5,5-octafluoro-1-Pentanol) Sulfosuccinate
Park, Ji-Young ; Kim, Mi-Yeong ; Lee, Chang-Ha ; Lim, Jong-Sung ;
Korean Chemical Engineering Research, volume 42, issue 3, 2004, Pages 296~303
Phase behavior of the water in
microemulsion that nano size water droplets were dispersed into
were investigated, and considered the effect of the organic solvents on the phase behavior of this. In order to form the microemulsion, sodium salt of bis(2,2,3,3,4,4,5,5-octafluoro-1-pentanol) sulfosuccinate(F-AOT) surfactant which has
philic chains and hydrophilic head group simultaneously was synthesized. The added ten organic solvents were iso-propanol, n-propanol, ethanol, methanol (group 1), tetrahydrofuran, pyridine, 2-methoxyethanol (group 2), acetonitrile, acetone, 1,4-dioxane (group 3). These organic solvents were added into
and the cloud points of this microemulsion were measured. In case that the organic solvents of group 1 were added into
microemulsion, the cloud points were 22.15-28.70 MPa (T = 317.1-363.20 K) for methanol, 18.5-28.40 MPa (T = 307.5-357.20 K) for ethanol, 17.40-28.32 MPa (T=307.20-365.30 K) for n-propanol, 15.15-26.49 MPa (T=309.15-365.60 K) for iso-propanol. In case of the organic solvent of group 2, the cloud points were 19.3-28.2 MPa (T=308.15-367 K) for acetone, 18.8-26.3 MPa (T = 307-356.1 K) for 2-methoxyethanol, 18.6-27.9 MPa (T = 309.1-368.2 K) for tetrahydrofuran, 16.2- 25.9 MPa (T = 307.1-367.5 K) for pyridine. In case of the organic solvent of group 3, the cloud points were 16.52-26.74 MPa (T=307-359.3 K) for acetonitrile, 19.3-28.2 MPa (T=308.15-367.0 K) for acetone, and 20.1-28.8 MPa (T=309.15-364.15 K) for 1,4-dioxane. According to the results, the cloud point of water+surfactant+organic solvent+
becomes lower in adding the ten orgarnic solvents, and the phase behavior of this microemulsion was related to the solubility parameter of organic solvent and
Filtering Characteristics of Polymer Solution
Yim, Sung-Sam ; Song, Yun-Min ; Kim, Do-Hyung ;
Korean Chemical Engineering Research, volume 42, issue 3, 2004, Pages 304~310
To know the filtration characteristics of the polymer suspensions, the cake filtration of polyethylene glycol, dextran and cationic polymer coagulant were performed by 'filtration-permeation' method. The pore diameter of the filter media utilized were
. By analyzing the experimental 'filtration-permeation' results, the permeation of polyethylene glycol - which has relatively small molecular weight - through the filter medium, the phenomenon of filter medium blocking by dextran which has larger molecular weight, and the cake filtration characteristics of polymer coagulant solution has been confirmed.
Phase Behavior of Poly(L-lactide) and Polycaprolactone in Various Solvents at High Pressure
Park, Ji-Young ; Lim, Jong-Sung ; Park, Ki-Hyun ; Yoo, Ki-Pung ;
Korean Chemical Engineering Research, volume 42, issue 3, 2004, Pages 311~317
Cloud points of poly(L-lactide) and polycaprolactone in chlorodifluoromethane(HCFC-22), trifluoromethane(HFC-23), difluoroethane(HFC-32), pentafluoroethane(HFC-125), 1,1,1-trifluoroethane(HFC-143a), 1,1-difluoroethane(HFC-152a), 1,1,1,2,3,3,3-heptafluoropropane(HFC-227ea) and dimethylether(DME) at high pressure were measured using the variable volume cell apparatus for. L-PLA was dissolved well in DME and HCFC-22 below 25.0 MPa, and dissolved in HFC-23, HFC-32, and HFC-152a in the range of 53.2-116.02 MPa but, it was not dissolved in HFC-125, HFC-143a, and HFC-227ea even at 413.15 K and 160 MPa. The cloud point of L-PLA was measured with L-PLA molecular weight(M.W.=80,000, 110,000, 230,000). The cloud point of L-PLA exhibited LCST(lower critical solution temperature) behavior in DME, HCFC-22, and HFC-23 and exhibited UCST(upper critical solution temperature) behavior in HFC-32 and HFC-152a. On the other hand, polycaprolactone(PCL), it was dissolved well in HCFC-22, HFC-143a, and DME below 36.9 MPa, and dissolved in HFC-152a in the range of 126.31-151.45 MPa but, was not dissolved in HFC-23, HFC-32, HFC-125, HFC-134a, and HFC-227ea even at 413.15 K and 160 MPa. Cloud point of L-PCL exhibited LCST behavior in HFC-143a, and exhibited UCST behavior in HFC-152a.
Characteristics on the Flow Field and Particle Behavior in a Bag Filter with Combining Centrifugal Force
Kim, Sang-Do ; Son, Jae-Ek ; Park, Young-Ok ; Chung, Dong-Kyu ; Kang, Yong ;
Korean Chemical Engineering Research, volume 42, issue 3, 2004, Pages 318~325
A new type bag filter that combines centrifugal force in existing bag filter system was developed, and its computational simulation was performed to examine characteristics on a flow field and particle behavior. The fluid coming in from the tangential direction forms strong vortex in the space between the inner and outer tube and the flow goes down along the hopper wall. Partially, this flow merges with the up-flow from the inner tube to the upper tube wall. The up-flow changes its direction at the shell plate where the bag filters are mounted and it starts to go down with a vortex along the central axis. Most of bag filters are located in down-flow region which this plays an important part to fall down to the hopper more easily when dust cake removed by cleaning.
Kinetics of the Formation of Poly(ethylene-co-1,4-cyclohexylenedimethylene) Terephthalate Oligomer by Various Catalysts
Park, Sang-Soon ; Choi, Joong-So ;
Korean Chemical Engineering Research, volume 42, issue 3, 2004, Pages 326~331
A kinetic analysis of the esterification of dimethyl terephthalate (DMT) with ethylene glycol (EG) and 1,4-cyclohexane dimethanol (CHDM) was investigated in the presence of various catalysts at
. The conversion was followed by the measurement of output of methanol which was distilled from the reactor. The catalytic activity was increased with the increase of molar ratio, agitator speed, and catalyst concentration. Also, the decreasing order in catalytic activity on the esterification was Ti > Pb > Zn > Mn > MBTO > Co > Cd > Mg > Li.
Analysis of Dispersion Behavior of Fluidized Particles in Gas-Liquid Countercurrent Fluidized Beds
Son, Sung-Mo ; Kim, Hyun-Tae ; Kang, Suk-Hwan ; Kang, Yong ; Kim, Sang-Done ;
Korean Chemical Engineering Research, volume 42, issue 3, 2004, Pages 332~337
Dispersion behaviors of fluidized particles have been investigated in a gas-liquid countercurrent fluidized bed of 0.152 m ID and 2.5 m in height. Since the dispersion flow of particles is highly irregular, stochastic analysis has been employed to analyze the behavior of dispersion characteristics. Pressure drop fluctuations have been measured and analyzed with the variation of time after change of the gas flow rate as a step function. Effects of gas and liquid velocities and particle kind (density) on the dispersion coefficient, fluctuating frequency and exiting rate of particles from the test section have been determined. It has been found that the dispersion behavior of particles can be classified into two states, heterogeneous and homogeneous expansion states, before it finally reached a new steady state. The dispersion coefficient and fluctuating frequency of particles increase with increasing gas or liquid velocity. The values of
and F in the beds of relatively higher density particles(PE) are higher than those of relatively lower density particles(PP). The values of
and F have been well correlated in terms of dimensionless groups.
Particles by Sol-Gel Method
Hwangn, Un-Yeon ; Kim, Yong-Ryul ;
Korean Chemical Engineering Research, volume 42, issue 3, 2004, Pages 338~344
In this study, spherical
particles are prepared by sol-gel method. From fourier transform infrared analysis, it was found that a molar ratio of [AcOH]/[TIP] = 4 participated in TIP modification reaction and the coordination number of Ti increased to 6 by the modification reaction. Water added in the titanyl acylate removed the isopropyl groups bonded to titanium atoms by monodentate mode. From the FT-IR and XRD analysis for various solutions and barium acetate solid, it was found that Ba-OAc bonds are not readily removed even in a strong alkaline solution.
and pseudo-barium acetate phases were found to coexist in as prepared powders. Barium oxalate and potassium carbonate intermediate phases formed during the thermal treatment of as-prepared powders due to decomposition of the pseudo-barium acetate phases. Crystallinity of
particles decreased along with increasing [AcOH]/[TIP] ratio and the final powders were produced by aggregation of the fine particle.
Process Analysis and Economic Evaluation for the Production of Enantiomerically Pure (R)-3-Hydroxybutyrate by Degradation of Bacterial Poly(3-Hydroxybutyrate)
Choi, Jong-Il ; Lee, Young ; Lee, Sang-Yup ;
Korean Chemical Engineering Research, volume 42, issue 3, 2004, Pages 345~354
Processes for the production of enantiomerically pure (R)-3-hydroxybutyrate (R3HB) by degradation of bacterial poly[(R)-3-hydroxybutyrate] (PHB) were analyzed by computer-aided process design. In this study, we have evaluated and economically compared process designs and processes for two different degradation methods which are chemical acidic-methanolysis and biological in vivo depolymerization. In the acidic methanolysis process by chemical reaction, the amount of organic solvent and productivity significantly affected the final price of R3HB. The condition for chemical process was dependent on the purification method of PHB from cells. For the annual production of 1,000 tonnes of R3HB, the process employing chemical methanolysis resulted in the production cost of $ 16.9/Kg R3HB. But, at the same scale, the process involving in vivo depolymerization can provide the most economical production of R3HB, $ 8.7/Kg. This study should show R3HB could be economically produced from bacterial PHB by in vivo depolymerization.
Desulfurization Characteristics of Low Sulfur Coals Prior to Combustion using Air Oxidation Process
Nam, Young-Woo ; Park, Kye-Sung ;
Korean Chemical Engineering Research, volume 42, issue 3, 2004, Pages 355~361
Desulfurization characteristics of low sulfur coals prior to combustion were studied using air oxidation process. The optimum desulfurization condition for the air oxidation process was obtained when experiments were carried out for 15-20 minutes at
. Sulfur removal efficiencies for bituminous and anthracite coals were in the range 28.7-54.1% and 23.4-50.0%, respectively. The effect of particle size of the coals on desulfurization efficiencies was proved to be insignificant. In the air oxidation process, changes of heating values after treatment were negligible within the experimental error. When steam was added to reduce the loss of carbon to the oxidation process, the sulfur removal efficiency of coals increased 2-3% and the heating value of anthracite coals was higher than that for bituminous ones.
A Study on Oil Adsorption of Expanded Gaphites
Park, Soo-Jin ; Kim, Ki-Seok ;
Korean Chemical Engineering Research, volume 42, issue 3, 2004, Pages 362~367
The expanded graphites (EG) prepared from graphite intercalation compounds (GICs) were investigated in expansion volume, loaded intercalant content, and oil adsorption behaviors. The expansion volume and loaded intercalant content of EG were measured by graduated cylinder and gravimetry of GICs, respectively. As a result, the expansion volume and loaded intercalant content of EG were increased with increasing the treatment temperature or the oxygen amount during the preparation of EG. From XRD analysis, the pattern of GICs showed that the
reflection of natural graphites was disappeared in a successful intercalation by the sulfuric acid as an intercalant. And, the original
reflection was again shown in the EG made by intercalant ejection during heating. The oil adsorption capacity of EG was found to be a maximum 30 g of ndodecane per 1 g of EG. It was noted that the oil adsorption behaviors were attributed to the capillary effect of large interparticle space in EG, resulting from increasing the cleavage-like pores on the EG surfaces.
Characteristics of Co-Deposition in Bi2212 Thin Films Fabricated by using the Ion Beam Sputtering Method
Cheon, Min-Woo ; Lim, Jung-Kwan ; Park, Yong-Pil ;
Korean Chemical Engineering Research, volume 42, issue 3, 2004, Pages 368~370
The Bi2212 superconducting thin films were fabricated by using the ion beam sputtering method. As a result, although the composition of Bi2212 was set point, the phase of Bi2201, Bi2212 and Bi2223 was formed. The product region of these stable phases is indicated as inclined line in the direction of the right lower end from the Arrhenius plot of the substrate temperature-oxidation gas pressure, and are distributed in very small area. According to the result observing the surface of the thin film with SEM, even in case that the formed phase and the composition of the thin film agree, also it can be known that there are a number of the precipitates on the surface.
Low Temperature CO Oxidation over
Kim, Deog-Ki ; Shin, Chang-Sub ; Shin, Chae-Ho ;
Korean Chemical Engineering Research, volume 42, issue 3, 2004, Pages 371~374
The effects of the pretreatment temperature of
catalyst and the presence of a trace amount of water in the reactant stream on the reactivity in the low temperature CO oxidation have been investigated. The presence of ca. 5 ppm of water in the reactant stream was found to result in a notable deactivation of reactivity of the
catalyst, when the catalyst was pretreated at temperatures below
. In contrast, the presence of this small amount of water had no influence on the catalyst activity when the pretreatment temperature is elevated to
. In the reaction temperature range of
, a decrease of catalytic activity with increasing reaction temperature is observed. This means the existence of negative activation energy.