금속소재의 급속가열을 위한 순산소 직화가열설비의 적용특성 평가

조한창(Han Chang Cho),오혁진(Hyuk Jin Oh),조길원(Kil Won Cho) 한국연소학회 2010 KOSCOSYMPOSIUM논문집 Vol.- No.41

A study has been carried out to evaluate the performance of a commercial DFI (direct flame impingement) booster and to reduce the temperature difference along the strip width. The evaluation is accomplished by the analyses of NOx emissions, temperature rising of the strip and temperature difference along the strip width. The strip conditions (width and thickness), line speed and the flow rates of LNG and oxygen play a very important role. These operating conditions are controlled, and the strip temperature is measured using thin thermocouples located at the DFI inlet and outlet. It is found that the thermal efficiency of the DFI booster is lower than 57%. The strip temperature in the walk side is lower than that in the drive side due to the direction of the flue gas exhaust. High NOx emissions are measured because of the nitrogen used for the burner cooling Finally, the solutions for these problems discovered during the test operation are suggested.

다수대를 이용한 복사관 버너시스템에서 맥동연소기술

조한창(Han Chang Cho),오혁진(Hyuk Jin Oh) 한국연소학회 2011 KOSCOSYMPOSIUM논문집 Vol.- No.42

An experimental study was carried out in a heat treatment furnace to investigate the performance, such as NOx emission, enhancement of heat transfer, system stabilization and etc, of oscillating combustion applied in multi radiant tube burner system. A oscillating controller with solenoid valve were designed and used to control 20 valves. In a test furnace with one burner, NOx emission decreases by 40~50 % in 2.0㎐ and duty ratio 30%. As oscillating combustion was applied in radiant tube burner system, it is found that NOx emission, compared to no oscillation, could be reduced by 20~30% at 2.5㎐ without CO emission. However, as oscillating frequency was increased, effect of abatement of NOx emission is gradually reduced. From the measurement of furnace heating time from 100℃ to 900℃, heat transfer is increased by 4.0% at the oscillation of 2㎐. Temperature distribution of radiant tube surface is more uniform at oscillation of 2㎐ 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.

저열량 가스연료의 산소연소기술 실적용

조한창(Han Chang CHO),조길원(Kil Won CHO),김기홍(Ki Hong KIM) 한국연소학회 2008 KOSCOSYMPOSIUM논문집 Vol.- No.-

Low calorific combined gases, such as BFG, CFG, COG, and LDG, are generated at ironmaking and steelmaking processes. The BFG(Blast Furnace Gas), having lowest heating value among these combined gases, is not basically burned with mixing of only air as oxidant. Meanwhile, using oxygen as oxidant, the BFG could be burned. The purpose of this work is to develop an oxyfuel burner of low calorific BFG and to apply the burner to a large scale furnace at Pohang steel works. The basic burner model for stable BFG-O2 flame is proposed and optimized: oxygen is discharged through a nozzle in the center of the burner and BFG is supplied with its concentric tube. The nozzle rim of oxygen plays a important role to stabilize and hold the flame. A real scale burner for real scale furnace at chemical process plant is developed through scale up from the small scale model. The developed burner is attached in real scale furnace and field tests are carried out. From the tests, it is confirmed that the developed burner system is successfully operated in the furnace and the effect is positive in the side of low NOx emission under l0ppm and energy saving by 37% in heating value basis

유동변수들이 석탄가스화에 미치는 민감도에 대한 수치적연구

조한창(Han Chang CHO),신현동(Hyun Dong SHIN) 한국연소학회 1999 한국연소학회지 Vol.4 No.1

저열량 제철 부생가스의 순산소 연소 버너 개발

조한창(Han Chang Cho),홍정구(Jeong Ku Hong),오혁진(Hyuk Jin Oh),조길원(Kil Won Cho) 한국연소학회 2010 KOSCOSYMPOSIUM논문집 Vol.- No.40

A study was carried out in a bench-scale test furnace to develop the oxyfuel burner with low calorific by-product gas below 700㎉/N㎥. To do this, a bench scale test furnace is improved and the test burners of 300M㎈/h are designed. Oxygen in the burner is discharged through a nozzle in the center of the burner and gas is supplied with its concentric tube. The nozzle rim of oxygen plays a important role to stabilize and hold the flame. From the tests, it is confirmed that using oxygen burner, low calorific by-product gases below 700㎉/N㎥ can be used with stable flame and NOx is emitted below 30ppm at 11% oxygen concentration in exhaust gases.

맥동연소기술이 접목된 복사관 버너에서의 NOx 배출 특성

조한창(Han Chang CHO),조길원(Kil Won CHO),김후중(Hoo Joong KIM) 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 NOx 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 NOx emission, compared to no oscillation, could be reduced by 38% at 90~120rpm (1.5~2.0㎐). However, as oscillating frequency was increased, effect of abatement of NOx emission is gradually reduced. From the measurement of furnace heating time from 100℃ to 720℃, 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.

저열량 합성가스의 산소부화 연소기술

조한창(Han Chang CHO),홍정구(Jung Goo HONG),조길원(Kil Won CHO),김기홍(Ki Hong KIM) 한국연소학회 2009 KOSCOSYMPOSIUM논문집 Vol.- No.38

A study was carried out in a bench-scale test furnace to investigate the flame stabilization and NOx emission in the burner used at hot rolling mill with oxygen-enriched air and combined gases generated in steel works. To do this, a bench scale test furnace is made and the test burners of 1000M㎈/h are designed. From the tests of NOx emission, it is confirmed that low calorific combined gases of 1500㎉/N㎥ can could be used with over 45% oxygen-composed air, but mix gas of 2800㎉/N㎥ must not be over 40% oxygen-composed air. In low calorific combined gases of 1500㎉/N㎥, the control of flame liftoff should be considered for the design of the burner.

열처리로에서 가진연소기술의 적용성 평가

조한창(Han Chang Cho),조길원(Kil Won Cho) 한국연소학회 2009 KOSCOSYMPOSIUM논문집 Vol.- No.39

An experimental study was carried out in a real scale test furnace to investigate the performance, such as NOx emission, enhancement of heat transfer, uniformity of temperature, and etc, of oscillating combustion applied in radiant tube burner system. A oscillating controller with solenoid valve were designed and used. Two burners used in steel industry were tested in this study. The fuel, used commercial LPG in this study, was only oscillated using the oscillating controller with a solenoid valve. As oscillating combustion was applied in radiant tube burner system, it is found that NOx emission, compared to no oscillation, could be reduced by 20~30% at 2.5㎐ without CO emission. However, as oscillating frequency was increased, effect of abatement of NOx emission is gradually reduced. From the measurement of furnace heating time from 100℃ to 900℃, heat transfer is increased by 4.0% at the oscillation of 2㎐. Temperature distribution of radiant tube surface is more uniform at oscillation of 2Hz 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.

구형 축열체를 사용한 축열기의 성능예측: 압력손실과 열전달의 관계

조한창(Han Chang CHO),조길원(Kil Won CHO),이용국(Yong Kuk LEE) 대한기계학회 2002 대한기계학회 춘추학술대회 Vol.2002 No.5

Heat regenerator occupied by regenerative materials improves thermal efficiency of regenerative<br/> combustion system through the recovery of sensible heat of exhaust gases. By using one-dimensional twophase<br/> fluid dynamics model, the unsteady thermal flow of heat regenerator with spherical particles, were<br/> numerically simulated to evaluate the heat transfer and pressure drop and to suggest the parameter for<br/> designing heat regenerator. It takes about 7 hours for the steady state of the flow field in regenerator, which<br/> heat absorption of regenerative particle is concurrent with the magnitude of heat desorption. The regenerative<br/> particle experiences small temperature fluctuation below 10K during the reversing process. The thermal flow<br/> in heat regenerator varies with inlet velocity of exhaust gas and air, configuration of regenerator(crosssectional<br/> area and length) and diameter of regenerative particle. As the gas velocity increases, the heat transfer<br/> between gas and particle enhances and pressure losses also increase. As particle diameter decreases, the air is<br/> preheated higher and the exhaust gases are cooled lower with the increase of pressure losses.

미분탄화염에서 가열률이 화염선단의 거동에 미치는 영향

조한창,박정규,신현동,Cho, Han Chang,Park, Jung Kyu,Shin, Hyun Dong 대한기계학회 1999 大韓機械學會論文集B Vol.23 No.5

An experimental study was carried out in two laboratory-scale reactors to investigate the effect of heating rate on the behavior of flame front in a pulverized coal flame. Each. reactors had different heating mechanisms. For reactor A losing large heat through transparent quartz wall. pulverized coal particles were ignited by secondary air of 1050K. Flame front could be visualized through the transparent wall. Reactor B was insulated with castable refractory to minimize the heat loss through the reactor wall and accompanied with secondary air of 573K. Flame front was estimated from the gas temperature and species concentration measured using R-type thermocouple(Pt-Pt/Rh 13%) and gas chromatograph at various coal-air ratios and swirl intensities. The flame front position was closely related with the magnitude of heating rate. The heating rate for lifted flame was of the order of $10^4$ to $10^5K/s$ and for coal Ignition at least over $10^4K/s$. The heating mechanism had little impact on the extinction limits. The weak swirl number of 0.68 forced the flame front to move toward the upstream by the rapid mixing of coal and air. The primary/secondary momentum ratio was an inappropriate variable to distinct the liftoff of flame.