• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.25 no.10
• /
• pp.116-124
• /
• 2011

In this work, the effect of the initial concentration of methanol and ethanol, and the addition of oxygen molecules were discussed to improve the hydrogen generation using non-thermal plasma reactor effectively. In addition, the effect of ozone decomposition catalyst of manganese dioxide and its quantity was investigated. First, hydrogen concentration increased until an initial concentration of about 40,000[ppm] of methanol and thereafter it was saturated. Henceforth, hydrogen concentration decreased with increasing the oxygen percent on the carrier gas of nitrogen about both substances. Related with the effect of catalyst, it increased upto 60[g], but it was not changed largely after that. Consequently, it is confirmed that the hybrid process using plasma process and catalytic surface chemical reaction is a very promising way to increase the efficiency of hydrogen generation as investigated in this work.

• Journal of the Korean Applied Science and Technology
• /
• v.31 no.4
• /
• pp.541-548
• /
• 2014

This study was performed to obtain high conversion efficiency of $C_7H_8$ using non-thermal plasma and metal-supported catalyst. Adsorption-desorption characteristics of toluene was performed using 4A type (Zeolite) filled in a concentration reactor. Through this test, it was found that the concentration reactor has 0.020 g/g of adsorption capacity (at ambient temperature and pressure) and 3,600 ppm of desorption property at $150^{\circ}C$ (with in 20 min). In case of developed catalyst, toluene decomposition rate of Pd-AO (Pd coated catalyst) was better than Pd/Cu-AO and Pd/Ag-AO (Pd/Ag composite metal catalyst). Developed non-thermal plasma system was obtained flame amplification effect using injection process of desorbed tolune, and 98% of removal efficiency.

• Nuclear Engineering and Technology
• /
• v.46 no.5
• /
• pp.655-666
• /
• 2014

The CUPID code has been developed at KAERI for a transient, three-dimensional analysis of a two-phase flow in light water nuclear reactor components. It can provide both a component-scale and a CFD-scale simulation by using a porous media or an open media model for a two-phase flow. In this paper, recent advances in the CUPID code are presented in three sections. First, the domain decomposition parallel method implemented in the CUPID code is described with the parallel efficiency test for multiple processors. Then, the coupling of CUPID-MARS via heat structure is introduced, where CUPID has been coupled with a system-scale thermal-hydraulics code, MARS, through the heat structure. The coupled code has been applied to a multi-scale thermal-hydraulic analysis of a pool mixing test. Finally, CUPID-SG is developed for analyzing two-phase flows in PWR steam generators. Physical models and validation results of CUPID-SG are discussed.

• Applied Chemistry for Engineering
• /
• v.28 no.2
• /
• pp.171-176
• /
• 2017

The nitrogen plasma thermal decomposition and recovery processes for $CHClF_2$ (Chlorodifluoromethane) refringent were investigated. The steam generator was employed to provide superheated steam reactor, supporting the decomposition reaction of refringent. Even though over 94% of R-22 was decomposed on the condition of 60 A and 9.0 kW, a higher power and specific energy density were required to achieve the complete combustion of carbon materials. In the operating condition of 60 A and 12.6 kW, $O_2$/R-22 ratio in reactants gases are a key factor to obtain much higher decomposition ratio during process. It should be noticed that injecting the mixture of $O_2$ and air was much more effective than injecting the air consisting equivalent $O_2$ amount.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2010.05a
• /
• pp.373-376
• /
• 2010

The characteristics of thermal-resistance catalyst for $N_2O$ propellant decomposition were studied in the present study. Si was added to the $Al_2O_3$ support to stabilize its surface area at high temperature (> $1000^{\circ}C$). Ru was used as a catalyst for $N_2O$ decomposition. The prepared catalysts were characterized using SEM, EDS and XRD analysis, and $N_2O$ conversion was measured as reaction temperatures. The Ru/$Al_2O_3$-Si catalyst showed better performance than Ru/$Al_2O_3$ catalyst.

• Applied Chemistry for Engineering
• /
• v.18 no.3
• /
• pp.213-217
• /
• 2007

Decomposition of benzene and selectivity of byproducts were investigated by using Dielectric Barrier Discharge (DBD) at atmospheric pressure. In order to increase the decomposition rate and selectivity of byproducts, two types of catalysts, H-ZSM-5 and Na-Y, were optionally employed inside the reactor of the process. The decomposition efficiency of benzene was investigated on the DBD and DBD/catalyst systems at various processing parameters including discharge voltage, residence time, and concentration of benzene. The results showed that, compared with the DBD only, the catalyst-assisted DBD process as a hybrid discharge type had an improved decomposition efficiency at the same process conditions of discharge voltage and residence time

• Transactions of the Korean hydrogen and new energy society
• /
• v.13 no.3
• /
• pp.249-258
• /
• 2002

Thermochemical water-splitting IS(Iodine-Sulfur) process has been investigating for large-scale hydrogen production. For the construction of an efficient process scheme, two kinds of membrane technologies are under investigating to improve the hydrogen producing HI decomposition step. One is a concentration of HI in quasi-azeotropic HIx ($HI-H_2O-I_2$) solution by elecro-electrodialysis. It was confirmed that HI concentrated from the $HI-H_2O-I_2$ solution with a molar ratio of 1:5:1 at $80^{\circ}C$. The other is a membrane reactor to enhance the one-pass conversion of thermal decomposition reaction of gaseous hydrogen iodide (HI). It was found from the simulation study that the conversion of over 0.9 would be attainable using the membrane reactor using the gas permeation properties of the prepared silica hydrogen permselective membrane by chemical vapor deposition (CVD). Design criterion of the membrane reactor was also discussed.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2009.05a
• /
• pp.159-162
• /
• 2009

In temperature controlled batch reactor, the effect of temperature and contact metals on the thermal stability of Exo-tricyclo[$5.2.1.0^{2,6}$]decane (tricyclodecane, exo-THDCP) were investigated by use of GC/MS. And the characteristic of metal in contact with tricyclodecane were analyzed by SEM-EDX. In fuel temperature variation test, thermal decomposition of exo-THDCP was occurred at $350^{\circ}C$. In case of fuel contact metals, Titanium was less effective to decomposition of exo-THDCP than stainless steel 304, 316.

• Journal of Korean Society for Atmospheric Environment
• /
• v.14 no.4
• /
• pp.293-302
• /
• 1998

This study was performed to investigate the behavior of chlorobenzenes (CIBZS) and chlorophenols (CIPhs) in a thermally treated MSWI fly ash. The experiment was carried out in a fixed bed reactor at the temperature range of 300~$600^{\circ}C$. Reaction time range was between 30 and 120 minutes, and NB and 02 gases were used as carrier gas. The decomposition rate of CIBZS was more affected by reaction time than by the reaction temperature. The decomposition rate of CIPhs was affected by both parameters. Decomposition rate of CIBZS and CIPhs reached 80.4% and 96.6% at $600^{\circ}C$, 120 min, respectively. Considering the effect of O2 content, decomposition rate of CIBZS and CIPhs was the highest at 10% of O2 content. Declorination and decomposition reactions Pere investigated by analyzing homologue distribution. Higher chlorinated CIBZS and CIPhs homologue decreased but lower chlorinated compounds increased with the increase of temperature. Effect of O2 on the homologue distribution of these compounds was not clear in the range of our experiment conditions.

• Proceedings of the KSME Conference
• /
• 2003.04a
• /
• pp.131-136
• /
• 2003

CF8M cast austenitic stainless steel is used for several components such as primary coolant piping, elbow, pump casing, and valve bodies in light water reactors. These components are subject to thermal aging at the reactor operating temperature. Thermal aging results in spinodal decomposition of the delta-ferrite leading to increased strength and decreased toughness. In this study, three kinds of the aged CF8M specimen were prepared using an artificially simulated aging method. The objective of this study is to summarize the method of estimating ferrite contents, Charpy impact energy and J-R curve, and to evaluate the thermal embrittlement of the CF8M cast austenitic stainless steel piping used in the domestic nuclear power plants.