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조길원,박흥수,이용국 ( Kil Won Cho,Heung Su Park,Yong Kuk Lee ) 한국화학공학회 1991 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.29 No.2
Pilot scale combustion experiments for two types of gas burner, namely 1- and 2-staged firing burners, were carried out to examine the combustion characteristics of the burners for reheating furnace. The mixture of commercial propane and nitrogen was used as the experimental fuel. For the 1-staged burner prevailing in reheating furnaces, flame stability, flame shape, temperature and flue gas composition were measured and analyzed over various experimental conditions. Performance comparison of the two types of burner was done, also. Compared with the 1-staged burner, the 2-staged burner was found to be effective in reducing NO_χ emission and in enhancing thermal efficiency.
맥동연소기술이 접목된 복사관 버너에서의 NO<sub>X</sub> 배출 특성
조한창,조길원,김후중,Cho, Han-Chang,Cho, Kil-Won,Kim, Hoo-Joong 대한기계학회 2008 大韓機械學會論文集B Vol.32 No.2
An experimental study was carried out in a small-scale test furnace to investigate the performance, such as $NO_X$ emission, enhancement of heat transfer, uniformity of temperature, and etc, of oscillating combustion applied in radiant tube burner system. A premixed type burner and a cyclic oscillating control valve were designed and used. The fuel, used commercial LPG in this study, was only oscillated using the cyclic oscillating control valve. As oscillating combustion was applied in radiant tube burner system, it is found that $NO_X$ emission, compared to no oscillation, could be reduced by 38% at $90{\sim}120rpm\;(1.5{\sim}2.0Hz)$. However, as oscillating frequency was increased, effect of abatement of $NO_X$ emission is gradually reduced. From the measurement of furnace heating time from $100^{\circ}C$ to $720^{\circ}C$, heat transfer is increased by 11.5% at the oscillation of 120rpm. Temperature distribution of radiant tube surface is more uniform at oscillation of 120rpm with decrease of the peak temperature and increase of low temperature. From these results, it is confirmed that oscillating combustion is useful in radiant tube burner system.
조한창,조길원,이용국,Cho, Han-Chang,Cho, Kil-Won,Lee, Yong-Kuk 대한기계학회 2003 大韓機械學會論文集B Vol.27 No.10
Heat regenerator occupied by regenerative materials improves thermal efficiency of combustion system through the recovery of sensible heat of exhaust gases. By using one-dimensional two-phase fluid dynamics model, the unsteady thermal flow of regenerator with spherical particles, was numerically analyzed to evaluate the heat transfer and pressure losses and to derive the design parameter for heat regenerator. It is confirmed that the computational results, such as air preheat temperature, exhausted gases outlet temperature, and pressure losses, agreed well with the experimental data. The thermal flow in heat regenerator varies with porosity, configuration of regenerator and diameter of regenerative particle. As the gas velocity increases with decreasing the cross-sectional area of the regenerator, the heat transfer between gas and particle enhances and pressure losses decrease. As particle diameter decreases, the air is preheated higher and the exhaust gases are cooled lower with the increase of pressure losses. Assuming a given exhaust gases temperature at the regenerator outlet, the regenerator need to be linearly lengthened with inlet Reynolds number of exhaust gases, which is defined as a regenerator design parameter.
한종훈,조길원,이건홍 ( Jong Hun Han,Kil Won Cho,Kun Hong Lee ) 한국화학공학회 1996 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.34 No.6
Expanded graphite powders were prepared by heating natural flake graphites intercalated with sulfuric acid. Graphite matrices were fabricated by pressing expanded graphite powders. Impregnation of salts into the graphite matrices were done using vacuum filtration with 20 wt% CaCl₂ solution followed by vacuum drying at 200℃ and 20 ㎪. Techniques used to examine the properties of blocks include EDAX and EPMA for amount and distribution of salts in the block, Hepycnometer for porosity, permporometer for gas permeability and transient 1-dimensional heat flow technique for thermal conductivity measurement. Basic chemical heat pump system is used to examine the dimensional stability and temperature distribution for blocks in the reactor. Results showed that Darcy`s permeability constants of graphite matrices were in 0.01-l.0 Darcy at △P=0.8 bar. For graphite matrices with p_b=100-400 ㎏/㎥, thermal conductivities were in the range of 4-22 W/mK. CaCl₂ was uniformly dispersed on the surface of expanded graphites in the block. The porosities of blocks were in the range of 0.4-0.83. The dimension of blocks was found to be more stabilized as bulk density increases. Temperature profile was governed by the reaction kinetics at the initial stage and by the external heat transfer in the long run.