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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Korean Chemical Engineering Research
Journal Basic Information
Journal DOI :
The Korean Institute of Chemical Engineers
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Volume & Issues
Volume 46, Issue 6 - Dec 2008
Volume 46, Issue 5 - Oct 2008
Volume 46, Issue 4 - Aug 2008
Volume 46, Issue 3 - Jun 2008
Volume 46, Issue 2 - Apr 2008
Volume 46, Issue 1 - Feb 2008
Selecting the target year
Production of Bio-energy from Marine Algae: Status and Perspectives
Park, Jae-Il ; Woo, Hee-Chul ; Lee, Jae-Hwa ;
Korean Chemical Engineering Research, volume 46, issue 5, 2008, Pages 833~844
Bio-energy offers the opportunity to lessen fossil fuel consumption. Energy derived from solar, wind, hydroelectric, geothermal, and biomass sources are considered renewable. Because most forms of bio-energy are derive deither directly or indirectly from the sun, there is an abundant supply of renewable energy available, unlike fossil fuels. The use of bio-energy also provides environmental, economic and political benefits. Bio-energy can be produced from a marine source such as biomass provides a CO2 neutral, non-polluting form of energy. In this paper, the potential of marine biomass is increasingly discussed, given the size of the resource in that more than three quarters of the surface of planet earth is covered by water.
Characteristics of Oxidative Desulfurization(ODS) of Sulfur Compounds in Diesel Fuel over Ti-grafted SBA-15 Catalyst
Cho, Chin-Soo ; Jeong, Kwang-Eun ; Chae, Ho-Jeong ; Kim, Chul-Ung ; Jeong, Soon-Yong ; Oh, Sung-Geun ;
Korean Chemical Engineering Research, volume 46, issue 5, 2008, Pages 845~851
Oxidative desulfurizaton of model sulfur compounds and Industrial diesel fuel(LCO; Light Cycle Oil) over Ti-grafted SBA-15 catalyst was studied in a batch reactor with tert-Butyl Hydroperoxide(TBHP) as oxidant. Effects of Ti loading, TBHP/Sulfur mole ratio, reaction temperature on ODS activity and kinetic parameters were investigated. Tigrafted SBA-15 catalyst showed higher sulfur removal activity in the oxidative desulfurization reaction of refractory sulfur compounds(DBT and 4, 6-DMDBT) and LCO, suggesting that Ti-grafted SBA-15 catalyst could be a good candidate for ODS catalyst.
Degradation of VOC by Photocatalysts and Dark Discharge Hybrid Systems
Jung, Ji-Hoon ;
Korean Chemical Engineering Research, volume 46, issue 5, 2008, Pages 852~857
The immobilization technique is important to extend the application field of a photocatalyst. Titanium surface was changed into a TiO2 thin film by the anodizing process. The anodized TiO2 had photocatalytic activity, and showed sponge like shape. The photocatalytic degradation of gas phase acetaldehyde and VOCs by anodized titania has been studied in various initial concentrations, humidity and discharge potentials. The reactivity of anodized titania was increased with relative humidity, but excessive humidity led to a decrease of the reaction rate. The electric dark discharge that was combined with photocatalytic reaction enhanced the decomposition rate of the organic compounds. But excessively applied voltage caused corona discharge, which decreased the reaction rate. Optimum relative humidity was 40% and discharge potential was 5 kV under dark discharge region in photocatalytic reaction.
The Optimum Condition of SSF to Ethanol Production from Starch Biomass
Na, Jong-Bon ; Kim, Jun-Seok ;
Korean Chemical Engineering Research, volume 46, issue 5, 2008, Pages 858~862
The Simultaneous Saccharification and Fermentation(SSF) of ethanol production from potato starch studied with respect to growth pH, temperature, substrate concentration. The glucoamylase and Saccharomyceses cerevisiae have a capacity to carry out a single stage SSF process for ethanol production. The characteristics, termed as starch hydrolysis, accumulation of glucose, ethanol production and biomass formation, were affected with variation in pH, temperature and starch concentration. The maximum ethanol concentration of 12.9g/l was obtained using a starch concentration 30g/l, which represent an ethanol yield of 86%. The optimum conditions for the maximum ethanol yield were found to be a temperature of 38, pH of 4.0 and fermentation time of 18hr. Thus by using the control composite design, it is possible to determine the accurate values of the fermentation parameters where maximum production of ethanol occurs.
Preparation of Electroless Copper Plated Activated Carbon Fiber Catalyst and Reactive Evaluation of NO Removal
Yoon, Hee-Seung ; Oh, Jong-Hyun ; Lee, Hyung-Keun ; Jeon, Jong-Ki ; Ryu, Seung-Kon ;
Korean Chemical Engineering Research, volume 46, issue 5, 2008, Pages 863~867
Pitch based activated carbon fiber(ACF) was prepared from reformed naphtha cracking bottom oil(NCB oil) by melt spinning. The fibers obtained were stabilized, carbonized, and then steam activated. The ACF was sensitized with Pd-Sn catalytic nuclei via a single-step activation approach. This sensitized ACF was used as precursors for obtaining copper plated ACFs via electroless plating. ACFs uniformly decorated with metal particles were obtained with reduced copper plating in the reaction solution. Effects of the amount of copper on characteristics of ACF/Cu catalysts were investigated through BET surface area, X-ray diffraction, scanning emission microscopy, and ICP. The amount of copper increased with plating time, but the surface area as well as the pore volume decreased. NO conversion increased with reaction temperature. NO conversion decreased with increasing the amount of copper, which is seemed to be due to the reduction of surface area as well as the dispersion of copper.
Nickel Supported Adsorbent for Removing Carbon Monoxide
Son, Jung-Hwa ; Kim, Young-Ho ; Yoon, Song-Hun ; Park, Yong-Ki ; Lee, Chul-Wee ;
Korean Chemical Engineering Research, volume 46, issue 5, 2008, Pages 868~874
The Ni based adsorbent was prepared by co-precipitation method and its performance for removing carbon monoxide was investigated. Here, silica, aluminium silicate and γ-alumina were used for carriers of catalyst. Ni(NO3)2·6H2O and Ni(CH3COO)2·4H2O were utilized for Ni precursors. Precipitants were urea and citric acid. After precipitation of Ni salt on the carrier and following reduction using H2 gas, adsorbent was prepared and its performance was analyzed based on EDS, TPR and XRD experiments. In accordance with change of precipitation agents, Ni salts on carrier, carriers and reduction condition. Adsorbent performance for removing carbon monoxide was investigated. The adsorbent with 54.8 wt% Ni prepared using urea precipitant under reduction condition at 500 oC for 3 h exhibited the best CO removal performance.
Depolymerization of Polycarbonate Waste by Ethylene Glycol
Kim, Dong-Pil ; Kim, Bo-Kyung ; Cho, Young-Min ; Han, Myung-Wan ; Kim, Beom-Sik ;
Korean Chemical Engineering Research, volume 46, issue 5, 2008, Pages 875~879
A method for the depolymerization of polycarbonate waste by glycolysis using ethylene glycol without catalyst was explored in order to get the monomer bisphenol A (BPA). The effect of operation variables such as reaction time, reaction temperature, EG/PC weight ratio and the kinetic of glycolysis were studied. It was found that the polymerization reaction has two different activation energies depending on the reaction temperature. A drop in activation energy with temperature indicates that the reaction mechanism has shifted from one of a succession of elementary steps to another in the series. The maximum yield of BPA of 95.6% was achieved at reaction temperature 220 oC for 85min with EG/PC weight ratio 4.
Preparation of Mesoporous and Spherical-shaped Silica Particles by Spray Pyrolysis
Baek, Chul-Min ; Jung, Kyeong-Youl ; Park, Kyun-Young ; Park, Seung-Bin ; Cho, Sung-Baek ;
Korean Chemical Engineering Research, volume 46, issue 5, 2008, Pages 880~885
Spray pyrolysis was applied to prepare spherical silica particles with mesopores of a regular structure. The physical properties such as surface area, pore size, pore structure, particle size, and morphology were studied by BET, SEM, SAXS, and DLS analysis. At a fixed gas flow rate, the BET surface area changed from 200 to 1,290 m2/g as changing the CTAB/TEOS molar ratio from 0.05 to 0.3. At a fixed CTAB/TEOS ratio, the surface area of silica particles was varied from 1,062 to 1,305 m2/g with changing the gas flow rate from 10 to 40 l/min. The average pore size measured by BJH desorption was about 21~23 A and not significantly influenced by the CTAB/TEOS ratio and the gas flow rate. Finally, the highest surface area which was 1,305 m2/g were obtained when the CTAB/TEOS ratio and the gas flow rate were 0.2 and 20 l/min, respectively. According to SAXS analysis, the prepared silica particles showed a strong peak at 2θ=2.6o and two minor peaks around 2θ=4.4o and 5.1o, which are due to regular mesopores of hexagonal structure. The morphology of silica particles prepared were spherical shape and the average particle size was 1.0 μm.
Depolymerization of Fucoidan by Contact Glow Discharge Electrolysis(CGDE)
Bae, Jung-Shik ; Lee, Jung-Shik ; Kim, Young-Suk ; Sim, Woo-Jong ; Lee, Ho ; Chun, Ji-Yeon ; Park, Kwon-Pil ;
Korean Chemical Engineering Research, volume 46, issue 5, 2008, Pages 886~891
Contact glow discharge electrolysis(CGDE) is an unconventional electrolysis where plasma is sustained by D.C. glow discharge between an electrode and the surface of electrolyte surrounding it at high voltage. In this study, the behavior of CGDE in NaCl solution and the depolymerization of fucoidan by CGDE were investigated. After onset of CGDE, increase of voltage enhanced Glow discharge which resulted in low current density and low temperature in NaCl electrolyte. From the variation of molecular weight of fucoidan with the reaction time, it was demonstrated that the degradation of fucoidan followed a first-order rate law. Molecular weight of fucoidan treated with CGDE was about 40 times lower compared to initial fucoidan without content decrease of sulfate and fucos.
Application of Energy-Efficient Distillation System in Ethanol Process
Lee, Moon-Yong ; Kim, Young-Han ;
Korean Chemical Engineering Research, volume 46, issue 5, 2008, Pages 892~897
A new ethanol dehydration process utilizing a thermally coupled distillation column is proposed to reduce the energy requirement of the existing dehydration processes. An entrainer of benzene is used in the proposed system having the column profile similar to the equilibrium composition profile for the maximum distillation column efficiency, and the feed composition is arranged to close to the boundary of different distillation regions. It is found that the proposed distillation system gives some 18% of energy saving over the existing process. In addition, design guidelines are suggested for other azeotropic distillation process.
Electrochemical Properties of Polyaniline with Carbon Nanotube and
as Supercapacitor Electrodes
Yoon, Yu-Il ; Ko, Jang-Myoun ;
Korean Chemical Engineering Research, volume 46, issue 5, 2008, Pages 898~902
Prepared are three types of composite supercapacitor electrode, such as electroactive polyaniline(PAN), PAN/multi-walled carbon nanotube(CNT), and PAN/CNT/RuO2. Cyclic voltammetry was performed to investigate the supercapacitive properties of these electrodes in an electrolyte solution of 1.0M H2SO4. The PAN/CNT/RuO2 electrode showed the highest specific capacitance at all scan rates(e.g., 441 and 392 F g-1 at 100 and 1,000 mV s-1, respectively). In cycle performance, however, the PAN/CNT electrode demonstrated the best capacitance retention (66%) at 104th cycle.
Steady-state Simulation and Energy-saving Optimization of Monoethylene Glycol Production Process
Kim, Tae-Ki ; Jeon, In-Cheol ; Chung, Sung-Taik ;
Korean Chemical Engineering Research, volume 46, issue 5, 2008, Pages 903~914
This study was undertaken for the production capacity expansion and energy saving through entire process simulation and optimization for the commercial process of manufacturing monoethylene glycol as a staple from ethylene oxide. Aspen PlusTM(ver. 2006) was employed in the simulation and optimization work. The multicomponent vaporliquid equilibria involved in the process were calculated using the NRTL-RK equation. As for the binary interaction parameters required for a total of 91 binary systems, those for 8 systems were self-supplied by the simulator, those for 28 systems were estimated through regression of the VLE data in the literature, and the remainder were estimated with the estimation system built in the simulator. Subsequent to ascertaining the accuracy of the generated parameters through comparison between actual and simulated process data, sensitive variables highly affecting the process were searched and selected using sensitivity analysis tool in the simulator. The optimum operating conditions minimizing the total heat duty of the process were investigated using the optimization tool based on the successive quadratic programming in the simulator.
Simluation of PEM Fuel Cell with 2D Steady-state Model
Chung, Hyun-Seok ; Ha, Tae-Jung ; Kim, Hyo-Won ; Han, Chong-Hun ;
Korean Chemical Engineering Research, volume 46, issue 5, 2008, Pages 915~921
In most PEM fuel cell research, effects of cell geometry, physical properties of component such as membrane, carbon cloth, catalyst, etc. and water transport phenomena are key issues. The scope of these research was limited to single cell and stack except BOP(Balance of plant) of fuel cell. The research fouced on the fuel cell system usually neglect to consider detailed transport phenomena in the cell. The research of the fuel cell system was interested in a system performance and system dynamics. In this paper, the effect of the anode recirculation is calculated using the 2D steady-state model. For this work, 2D steady-state modeling and experiments are performed. For convenience of modifying of model equation, not commercial pakage but the in-house algorithm was used in simulation. For an vehicle industry, the analysis of the anode recirculation system helps the optimization of operating condition of the fuel cell.
Computational Fluid Dynamics(CFD) Simulation for a Pilot-scale Selective Non-catalytic Reduction(SNCR) Process Using Urea Solution
Nguyen, Thanh D. B. ; Kang, Tae-Ho ; Lim, Young-Il ; Kim, Seong-Joon ; Eom, Won-Hyeon ; Yoo, Kyung-Seun ;
Korean Chemical Engineering Research, volume 46, issue 5, 2008, Pages 922~930
The selective non-catalytic reduction(SNCR) performance is sensitive to the process parameters such as flow velocity, reaction temperature and mixing of reagent(ammonia or urea) with the flue gases. Therefore, the knowledge of the velocity field, temperature field and species concentration distribution is crucial for the design and operation of an effective SNCR injection system. In this work, a full-scale two-dimensional computational fluid dynamics(CFD)-based reacting model involving a droplet model is built and validated with the data obtained from a pilot-scale urea-based SNCR reactor installed with a 150 kW LPG burner. The kinetic mechanism with seven reactions for nitrogen oxides(NOx) reduction by urea-water solution is used to predict NOx reduction and ammonia slip. Using the turbulent reacting flow CFD model involving the discrete droplet phase, the CFD simulation results show maximum 20% difference from the experimental data for NO reduction. For NH3 slip, the simulation results have a similar tendency with the experimental data with regard to the temperature and the normalized stoichiometric ratio(NSR).
Rigorous Modeling and Simulation of Multi-tubular Reactor for Water Gas Shift Reaction
Park, Jun-Yong ; Choi, Young-Jae ; Kim, Ki-Hyun ; Oh, Min ;
Korean Chemical Engineering Research, volume 46, issue 5, 2008, Pages 931~937
Rigorous multiscale modelling and simulation of the MTR for WGSR was carried out to accurately predict the behavior of process variables and the reactor performance. The MTR consists of 4 fixed bed tube reactors packed with heterogeneous catalysts, as well as surrounding shell part for the cooling purpose. Considering that fluid flow field and reaction kinetics give a great influence on the reactor performance, employing multiscale methodology encompassing Computational Fluid Dynamics (CFD) and process modeling was natural and, in a sense, inevitable conclusion. Inlet and outlet temperature of the reactant fluid at the tube side was 345 oC and 390 oC, respectively and the CO conversion at the exit of the tube side with these conditions approached to about 0.89. At the shell side, the inlet and outlet temperature of the cooling fluid, which flows counter-currently to tube flow, was 190 oC and 240 oC. From this heat exchange, the energy saving was achieved for the flow at shell side and temperature of the tube side was properly controlled to obtain high CO conversion. The simulation results from this research were accurately comparable to the experimental data from various papers.
Electro-optic Properties of Polymer Dispersed Liquid Crystal Displays: Effect of BDVE(Butanediol Vinyl Ether) & Temprature Stability
No, Young-Seok ; Jeon, Chan-Wook ;
Korean Chemical Engineering Research, volume 46, issue 5, 2008, Pages 938~944
The electro-optic properties of polymer-dispersed liquid crystal cells containing BDVE(Butanediol vinyl ether) in PN393 base pre-polymer were examined. The higher the contents of BDVE, the smaller becomes the droplet size. However, the droplet size was saturated around 3 μm even at 40 wt% of BDVE. Both of contrast ratio and response time of PDLC cell fabricated with a new formula were found to be superior to the reference cell with PN393 by the factor of 4.9 and 0.15, respectively. However, the new formula made the operating voltage go higher compared to the reference cell of PN393 formula. Except for contrast ratio, response time as well as operating voltage were found to be highly stabilized by adding BDVE in PN393 base pre-polymer over the temperature range of 0~60 oC studied.
Synthesis and Characterization of Epoxy Based Nanocomposite Materials Using an Ultrasonicator
Lee, Do-Young ; Park, Kyung-Moon ; Park, Yoon-Kook ;
Korean Chemical Engineering Research, volume 46, issue 5, 2008, Pages 945~948
Nanocomposite materials provides efficient reinforcement, thermal endurance, and many other advantages depending on the additives used, with applications in the aerospace, automotive, and biomedical industries. Here, epoxy based nanocomposites were synthesized in the presence of Cloisite 15A and characterized with TEM, XRD, TGA, and DMA. To determine the effect of the clay d-spacing, Cloisite 20A was also used to synthesize the nanocompostes. In addition to the traditional hot plate method, an ultrasonicator was used to investigate the effect of different types of mixing on the properties of the nanocomposite; no significant effect was found. An examination of the nanocomposite morphology revealed that all the nanocomposites synthesized yielded an intercalated structure. When 5 wt% of Cloisite 15A was used with 20 min sonication time, the storage modulus increased 10% over the neat(no clay) nanocomposite. In general, the presence of Cloisite 15A produced a better storage modulus than Cloisite 20A.
A Study on the First Order Plus Time Delay Model Identification from Noisy Step Responses
Ju, Seung-Min ; Kim, Sung-Jin ; Byeon, Jeong-Uk ; Chun, Dae-Woong ; Sung, Su-Whan ; Lee, Jie-Tae ;
Korean Chemical Engineering Research, volume 46, issue 5, 2008, Pages 949~957
Estimating the first order plus time delay model on the basis of the step responses has been widely used in industry for the tuning of PID controllers. Even though various model identification methods from simple graphical approaches to complicated approaches based on least squares method have been proposed, simple approaches to incorporate noisy step responses are rarely available. In this research, we will compare and analyze recent approaches using the integrals of the step responses and develop an improved identification method to incorporate real situations more effectively.
Preparation of Dextran Microparticles by Using the SAS Process
Kang, Dong-Yuk ; Min, Byoung-Jun ; Rho, Seon-Gyun ; Kang, Choon-Hyoung ;
Korean Chemical Engineering Research, volume 46, issue 5, 2008, Pages 958~964
In this work, micro-sized dextran particles, which have recently been focused as one of the candidate materials for the Drug Delivery System(DDS), were prepared by means of the Supercritical Antisolvent (SAS) process with CO2. With dimethyl sulfoxide(DMSO) as the solvent, effects of the operating variables such as temperature (308.15~323.15 K), pressure(90~130 bar), solute concentration(10~20 mg/ml), and the molecular weight of the solute(Mw=37,500, 450,000) on the size and morphology of the resulting particles were thoroughly observed. The higher solute concentration led to the larger particles, however, the injection velocity of the solution and pressure did not show significant effects on the resulting particle size. With dextran of the lower molecular weight, the smallest particles were obtained at 313.15 K. On the other hand, the size of the particles from the high molecular weight dextran ranged between 0.1~0.5 μm with an incremental effect of the temperature and pressure. For the solute concentration of 5 mg/ml, the lower molecular weight dextran did not form discrete particles while aggregation of the particles appeared when the solute concentration exceeded 15 mg/ml for the higher molecular weight dextran. It is believed that if the solute concentration is too low, the degree of the supersaturation in the recrystallization chamber would not be sufficient for initiation of the nucleation and growth mechanism. Instead, the spinodal decomposition mechanism leads to formation of the island-like phase separation which appears similar to aggregation of the discrete particles. This effect would be more pronounced for the smaller molecular weight polymer system due to the narrower phase-splitting region.
Effect of Extraction Solvent on the Separation of Sulfur Components in Light Cycle Oil
Park, Su-Jin ; Jeong, Kwang-Eun ; Chae, Ho-Jeong ; Kim, Chul-Ung ; Jeong, Soon-Yong ; Koo, Kee-Kahb ;
Korean Chemical Engineering Research, volume 46, issue 5, 2008, Pages 965~970
The separation of sulfone components using light cycle oil(LCO) after oxidation was carried out by solvent extraction method using various polar solvents such as water, n-methyl-2-pyrrolidone(NMP), dimethyl sulfoxide, ethyl acetate, acetonitrile, dimethyl formamide, and methyl alcohol. It was found that phase separation between LCO layer and solvent occurred under mixed solvent adding a proper amount of water. The mixture solvent of NMP and water was a promising extraction solvent due to the selective removal and high distribution coefficient of sulfone component in LCO. 99.5% over of sulfur contents in LCO can be removed by 4 stages equilibrium extraction.
Simultaneous Removal of Ammonium and Nitrate by Natural Zeolite and Bacteria
Lee, Seon-Hee ; Lee, Ji-Hye ; Kim, Duk-Gyum ; Lee, Chang-Soo ; Kang, Kyung-Suk ; Kim, In-Ho ;
Korean Chemical Engineering Research, volume 46, issue 5, 2008, Pages 971~976
Water pollution by ammonium ion and nitrate is a common and growing problem in the ecosystem. Process of biological removal consists of nitrification and denitrification by bacteria. Ammonium is oxidized generally to nitrate by nitrification and nitrate is reduced to dinitrogen gas in the subsequent denitrification process. Although natural zeolite is well known for its ability to preferentially remove ammonium, it is not sufficiently removing ammonium ion and nitrate by adsorption. In order to overcome this problem, a method of biological removal with zeolite is used for simultaneous removal of ammonium and nitrate. As a result, in case of shaking culture with 1% seed and passing through zeolite column, the process revealed that ammonium ion could be removed completely after 14 hours. The removal of nitrate using columns with naturally adsorbed bacteria onto zeolite reached approximately 100% after 4 hours.
Comparison of Ethanol Fermentation by Saccharomyces cerevisiae CHY1077 and Zymomonas mobilis CHZ2501 from Starch Feedstocks
Choi, Gi-Wook ; Kang, Hyun-Woo ; Kim, Young-Ran ; Chung, Bong-Woo ;
Korean Chemical Engineering Research, volume 46, issue 5, 2008, Pages 977~982
The production of ethanol by microbial fermentation as an alternative energy source has been of interest because of increasing oil price. Saccharomyces cerevisiae and Zymomonas mobilis are two of the most widely used ethanol producers. In this study, characteristics of ethanol fermentation by Saccharomyces cerevisiae CHY1077 and Zymomonas mobilis CHZ2501 was compared. Brown rice, naked barley, and cassava were selected as representatives of the starch-based raw materials commercially available for ethanol production. The volumetric ethanol productivities by Saccharomyces cerevisiae from brown rice, naked barley and cassava were 0.68 g/l·h, 1.03 g/l·h and 1.28 g/l·h respectively. But for the Zymomonas mobilis, 2.19 g/l·h(brown rice), 2.60 g/l·h(naked barley) and 3.12 g/l·h(cassava) were obtained. Zymomonas mobilis was more efficient strain for ethanol production than S. cerevisiae.
Comparison of Particle Loading Characteristics onto Ceramic Candle Filters in Filtration System at Different Gas Inflow Pattern
Park, Seok-Joo ; Lim, Jeong-Hwan ; Lim, Kyeong-Soo ;
Korean Chemical Engineering Research, volume 46, issue 5, 2008, Pages 983~987
Computational simulation has been performed to design optimally the filtration system for IGCC pilot plant. It was analyzed how the different inflow pattern influences the flow field and the particle behavior in a filter vessel. The particle loading onto the filter surface lowers significantly and decreases dramatically with particle size when the dusty gas flows into the filter vessel with a shroud tube through a tangential inlet setup tangentially on the vessel outer wall. However, the particle loading is considerably high when the dusty gas enters the filter vessel through a normal inlet setup vertically on the vessel top wall, and the decrease of the particle loading with particle size is not steeper compared with the tangential inflow pattern.
Characteristics of NO Oxidation Using
Lee, Ki-Man ; Byun, Young-Chul ; Koh, Dong-Jun ; Shin, Dong-Nam ; Kim, Kyoung-Tae ; Ko, Kyoung-Bo ; Cho, Moo-Hyun ; Nam, Kung-Won ; Mok, Young-Sun ;
Korean Chemical Engineering Research, volume 46, issue 5, 2008, Pages 988~993
The characteristics of NO oxidation using sodium chlorite (NaClO2) powder have been investigated by a flow type packed-bed reactor, where the reaction temperature and the space velocity are varied in the range of 20~230 oC and 0.4-2.2×105 hr-1, respectively, and the simulation gas mixtures are composed of NO (0~200 ppm), NO2 (0-200 ppm), O2 (0~15%) and H2O (0~15%) within N2 balance. It has been found that the oxidation efficiency of NO depends greatly on the reaction temperature, exhibiting the existence of critical reaction temperature at about 170 oC where the oxidation efficiency of NO is maximized and then abruptly decreased with further increase of reaction temperature, resulting in being negligible over 190 oC. Such a behavior in the oxidation efficiency has been originated from the phase transition of NaClO2 at about 170 oC to form NaClO3, and NaCl which are chemically inactive toward the oxidation of NO. The chemical reaction of NO with NaClO2 has been observed to produce NO2, ClNO and ClNO2, whereas that of NO2 only OClO species. Additionally, we have also observed that the introduction of O2 and H2O has little influence on the oxidation of NO.
Evaluation of Adsorption Characteristics of the Media for Biofilter Design
Lee, Eun-Ju ; Lim, Kwang-Hee ;
Korean Chemical Engineering Research, volume 46, issue 5, 2008, Pages 994~1001
Freundlich isothermal adsorption parameters, applicable to such biofilter-model as process-lumping model(Lim’s model), for sterilized granular activated carbon(GAC), sterilized compost and sterilized equal volume mixture of GAC and compost were obtained and were compared each other, assuming that adsorbents are enclosed by water layer, in order to construct robust process-lumping biofilter model effective for wide-range of hydrophilic volatile organic compounds(VOC). In this investigation 0.04, 0.08, 0.12, 0.16, 0.2, 0.4, 0.8 and 1.0ml of ethanol were added to three kinds of adsorbent-media and were placed at 30°… under the wet condition of the media, which was the same as biofilter operating condition, until the adsorption reached the condition of equilibrium before each adsorbed amount of ethanol was obtained. Then adsorption capacity parameters(K) and adsorption exponents of Freundlich adsorption isotherm equation, which simulates the adsorbed amount of ethanol equilibrated with the ethanol concentration of the condensed water in the pore of the media, were constructed for sterilized granular activated carbon(GAC), sterilized compost and sterilized equal volume mixture of GAC and compost as (0.7566 and 5.070×10-7 mg-ethanol/mgmedia/(mg-ethanol/m3)0.7566), (0.8827 and 1.000×10-8 mg-ethanol/mgmedia/(mg-ethanol/m3)0.8827) and (0.5688 and 5.243×10-6 mg-ethanol/mgmedia/(mg-ethanol/m3)0.5688), respectively. These Freundlich isothermal adsorption parameters were applicable to the adsorption characteristics of biofilter media enclosed with bio-layer. The order of magnitude of the ratio of ethanol-air/water partition coefficient and toluene-air/water partition coefficient was almost consistent to that of ethanol-adsorbed amounts in this experiment with compost and in the investigation of Delhomenie et al. on toluene-adsorption to wet compost.
Hydrogen Production for PEMFC Application in Plasma Reforming System
Yang, Yoon-Cheol ; Chun, Young-Nam ;
Korean Chemical Engineering Research, volume 46, issue 5, 2008, Pages 1002~1007
The purpose of this paper studied the optimal hydrogen production condition of plasma reforming system to operate the PEMFC. Plasma reforming reactor used with Ni catalyst reactor at the same time, So H2 concentration increased. Also the WGS and PrOx reactor were designed to remove CO concentration under 10 ppm, because CO has effect on catalyst poisoning of PEMFC. The maximum H2 production condition in plasma reforming system was S/C ratio 3.2, CH4 flow rate 2.0 L/min, catalytic reactor temperature 700±5 oC and input power 900 W. At this time, the concentration of produced syngas was H2 70.2%, CO 7.5%, CO2 16.2%, CH4 1.8%. The hydrogen yield, hydrogen selectivity and CH4 conversion rate were 56.8%, 38.1% and 92.2% respectively. The energy efficiency and specific energy requirement were 37.0%, 183.6 kJ/mol. In additional, The experiment of CO2/CH4 ratio proceeded. Also WGS reactor experiment was proceeding on optimum condition of plasma reactor and the exit concentration were H2 68%, CO 337 ppm, CO2 24.0%, CH4 2.2%, C2H4 0.4%, C2H6 4.1%. At this time, experiment result of PrOx reactor were H2 51.9%, CO 0%, CO2 17.3%.
Evaluation of Denitrification Reactivity by the Supported Nanoscale Zero-Valent Iron Prepared in Ethanol-Water Solution
Park, Hee-Su ; Park, Yong-Min ; Oh, Soo-Kyeong ; Lee, Seong-Jae ; Choi, Yong-Su ; Lee, Sang-Hyup ;
Korean Chemical Engineering Research, volume 46, issue 5, 2008, Pages 1008~1012
Nanoscale zero-valent iron(nZVI) is famous for its high reactivity originated from its high surface area and it has received considerable attentions as one of the latest innovative technologies for treating contaminated groundwater. Due to its fine powdery form, nZVI has limited filed applications. The efforts to overcome this shortcoming by immobilizing nZVI on a supporting material have been made. This study investigated the differences of resin-supported nZVI's characteristics by changing the preparation methods and evaluated its reactivity. The borohydride reduction of an iron salt was proceeded in ethanol/water solvent containing a dispersant and the synthesis was conducted in the presence of ion-exchange resin. The resulting material was compared to that prepared in a conventional way of using de-ionized water by measuring the phyrical and chemical characteristics. BET surface area and Fe content of nZVI-attached resin was increased from 31.63 m2/g and 18.19 mg Fe/g to 38.10 m2/g and 22.44 mg Fe/g, respectively, by switching the solution medium from water to ethanol/water with a dispersant. The reactivity of each material was tested using nitrate solution without pH control. The pseudo first-order constant of 0.462 h-1 suggested the reactivity of resin-supported nZVI prepared in ethanol/water was increased 61 % compared to that of the conventional type of supported nZVI. The specific reaction rate constant based on surface area was also increased. The results suggest that this new supported nZVI can be used successfully in on-site remediation for contaminated groundwater.
Transformation of Nitrogen in the Form of Nitrate into Ammonia by Electrochemical Reaction
Lee, Jae-Kwang ; Kim, Do-Yeon ; Tak, Yong-Sug ;
Korean Chemical Engineering Research, volume 46, issue 5, 2008, Pages 1013~1016
Nitrogen in the form of nitrate was electrochemically reduced with different cathode materials including Fe, Ni, Cu, and Zn. Zn cathode shows the greatest electrocatalytic activity on the transformation of nitrate ions into ammonia and the NO3- removal efficiency has highest value at pH 8.5. Nitrogen in the form of nitrate was initially reduced into nitrite and sequentially, converted into nitrogen inside NH3. Nitrogen in the form of ammonia was completely removed by the reaction with HOCl.
Design of Thermally Coupled Distillation Process Utilizing Existing Columns
Lee, Moon-Yong ; Kim, Young-Han ;
Korean Chemical Engineering Research, volume 46, issue 5, 2008, Pages 1017~1022
Though many divided wall columns are implemented in field as energy-efficient distillation columns, its application is limited due to the difficulty of building a new column. A novel energy-efficient distillation system utilizing the existing columns is proposed here. The proposed can reduce the energy consumption by about 39% comparing with the existing system. And it is shown that the proposed improves the column operability over the existing. The tray numbers of the added columns have no significant influence on the composition of a side draw.