• Proceedings of the Membrane Society of Korea Conference
• /
• 2005.05a
• /
• pp.131-135
• /
• 2005

• Korean Chemical Engineering Research
• /
• v.46 no.4
• /
• pp.665-668
• /
• 2008

Propylene epoxidation by $H_2O_2$ (30% aqueous) as oxidant was studied in a semi-batch reactor using Ti-MCM-22 catalyst: Effects of reaction temperature, pressure, catalyst loading, solvent, and $H_2O_2$ concentration on $H_2O_2$ conversion (limiting reagent) were investigated. Product inhibition by propylene oxide was confirmed. Ti-MCM-22 maintained virtually the same catalytic performance over the 5 repeated cycles.

• Journal of the Korean Society of Combustion
• /
• v.16 no.2
• /
• pp.16-22
• /
• 2011

It is a challenging task to apply large detailed chemical mechanisms of fuel oxidation in simulation of complex combustion phenomena. There exist a few systematic methodologies to reduce detailed chemical mechanisms to smaller sizes involving less computational load. This research work concerns generation of a skeletal chemical mechanism by a directed relation graph with specified accuracy requirement. Two sequential stages for mechanism reduction are followed in a perfectly stirred reactor(PSR) for high temperature chemistry and to consider the autoignition delay time for low and high temperature chemistry. Reduction was performed for the detailed chemical mechanism of n-heptane consisting of 561 species and 2539 elementary reaction steps. Validation results show acceptable agreement for the autoignition delay time and the PSR calculation in wide parametric ranges of pressure, temperature and equivalence ratio.

• Korean Chemical Engineering Research
• /
• v.50 no.5
• /
• pp.908-912
• /
• 2012

Lauan sawdust was gasified by steam reforming for hydrogen production from biomass waste. The fixed bed gasification reactor with 1m height and 10.2 cm diameter was utilized for the analysis of temperature and catalysts effect. Steam was injected to the gasification reactor for the steam reforming effect. Lauan sawdust was mixed with potassium carbonate, sodium carbonate, calcium carbonate, sodium carbonate + potassium carbonate and magnesium carbonate + calcium carbonate catalysts of constant mass fraction of 8:2 which was injected to the fixed gasification equipment. The compositions of production gas of gasification reaction were analyzed at the temperature range from $400^{\circ}C$ to $700^{\circ}C$. Fractions of hydrogen, methane and carbon monoxide gas in the production gas increased when catalysts were used. Fractions of hydrogen, methane and carbon monoxide gas were increased with increasing temperature. The highest hydrogen yield was obtained with sodium carbonate catalyst.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.34 no.7
• /
• pp.89-96
• /
• 2006

The combustion temperature in gas generator should be kept below around 1,000K to avoid any possible thermal damages to turbine blade by adopting either fuel rich or oxidizer rich combustion. Thus, non-equilibrium chemical reaction dominates in the gas generator. Meanwhile, Kerosene is a compounded fuel mixed with various types of hydrocarbon elements and difficult to model the chemical kinetics. This study focus to model the non-equilibrium chemical reaction of kerosene/LOX with detailed kinetics developed by Dagaut using PSR(Perfectly stirred reactor) assumption. Also, droplet evaporation time is taken into account by calculating for the residence time of droplet and by decoupling reaction temperature from the reactor temperature. In Dagaut’s surrogate model for kerosene, chemical kinetics of kerosene consists of 1592 reaction steps with 207 chemical species. The comparison of calculation results with experimental data could provide very reliable and accurate numbers in the prediction of combustion gas temperature, species fraction and other gas properties.

• Korean Journal of Materials Research
• /
• v.16 no.1
• /
• pp.11-18
• /
• 2006

[ $Co_3O_4$ ] particles with non-aggregation characteristics were prepared by various conditions such as preparation temperature, flow rate of carrier gas, and concentration of spray solution using spray pyrolysis. The morphology and crystallinity of the preformed particles obtained by spray pyrolysis at various conditions affected the mean size and morphology of the post-treated $Co_3O_4$ particles. The preformed particles with hollow and porous morphology obtained from spray solution with citric acid and ethylene glycol turned to $Co_3O_4$ particles with nano size, regular morphology and non-aggregation characteristics after post-treatment at $800^{\circ}C$. On the other hand, the preformed particles obtained by the preparation conditions of short residence time of particles inside hot wall reactor and high reactor temperature turned to $Co_3O_4$ particles with aggregated morphology after post-treatment. The mean crystallite size and particle size of the $Co_3O_4$ particles prepared from optimum preparation conditions were 47 nm and 210 nm at post-treatment temperature of $800^{\circ}C$.

• Korean Chemical Engineering Research
• /
• v.45 no.4
• /
• pp.351-355
• /
• 2007

It is necessary to convert butene-2 into butene-1 with higher added-values through positional isomerization. In this study, hydro-isomerization of butene-2 with hydrogen over Pd/alumina catalysts was investigated in a fixed bed reactor. The yield of butene-1 over Ld-265 catalyst was higher than that over other catalysts. The yield of butene-1 was highest (5.3%) under the conditions of reaction temperature of $75^{\circ}C$, reaction pressure of 150 psig, 2-butene flow rate of 48 cc/h and hydrogen flow rate of 3 cc/min. We conducted simulation for the process composed of a hydro-isomerization reactor and a distillation tower. In the case of 78% of tray efficiency, we obtained over 99% pure butene-1 through a distillation tower with 171 steps (R=120).

• Korean Chemical Engineering Research
• /
• v.62 no.2
• /
• pp.181-190
• /
• 2024

Here, we develop a centrifugal microfluidic reactor with simple, fast, and high-throughput manner for the generation of magnetic Janus micro-adsorbents (MAs). By using the multi-micronozzle consisting of two separate aligned needles and centrifugal tubes, we have synthesized highly monodispersed Prussian blue- and magnetic nanoparticle-laden micro-adsorbents (PB-MNP-MAs). The enhanced cesium (Cs⁺) adsorption was demonstrated by conducting the adsorption isotherm and kinetics experiment which can be contributed to the porous nature of the Ca-alginate networks with a high surface area of embedded PB nanoparticles, resulting to perform rapid adsorption activity within 10 min. After Cs⁺ adsorption process, the as-synthesized PB-MNP-MAs were successfully harvested by introducing the external magnetic fields. Therefore, we believe that our findings can be provided new direction towards the development of advanced functional adsorbents in biological and environmental fields.

• Korean Chemical Engineering Research
• /
• v.55 no.6
• /
• pp.837-845
• /
• 2017

A recirculating integrated system composed of a fluidized biofilter filled with waste-tire crumb media fixed with return sludge from wastewater treatment facility of D dyeing industrial center, and a UV/photocatalytic reactor packed with calcined $TiO_2$ coated-glass beads as photocatalyst-support, was constructed and was run to treat authentic textile-dyeing wastewater from D-dyeing industrial center, which was mixed with an alkaline polyester-weight-reducing wastewater and a wastewater from sizing process. As a result, its total removal efficiency(RE(tot)) of $COD_{cr}$ and colors were ca. 81% and 55%, respectively. The synergy effect of the recirculating integrated system to enhance total removal efficiency(RE(tot)) of $COD_{cr}$ and colors were evaluated at most ca. 7% and 3%, respectively. The fluidized biofilter and the UV/photocatalytic reactor were responsible for ca. 94% and 6% of the total $COD_{cr}$ removal efficiency, respectively, and were also responsible for ca. 86% and 14% of the total color-removal efficiency, respectively. Thus, the degree of the UV/photocatalytic reactor-unit process's contribution to RE(tot) of color, was about 2.4 times of that to RE(tot) of $COD_{cr}$. Therefore, the UV/photocatalytic reactor facilitated the more effective elimination of colors by breaking down the chemical bonds oriented from colors of dyes such as azo-bond, than $COD_{cr}$. In addition, the effect of the removal efficiency of each unit process(i.e., the fluidized biofilter or the UV/photocatalytic reactor) of the recirculating integrated system on RE(tot) of $COD_{cr}$ and colors, was analysed by establishing its model equation with an analytic correlation.

• Journal of Microbiology and Biotechnology
• /
• v.4 no.3
• /
• pp.230-232
• /
• 1994

The enzymes $\alpha$-amylase and glucoamylase used in starch hydrolysis were found active in the supercritical carbon dioxide solvent Higher hydrolysis of starch sluny in supercritical $CO_2$ was achieved by operating the reactor for the first two hours with $\alpha$ -amylase and to subsequent addition of glucoamylase for continued hydrolysis.