• Journal of the Korean Society of Combustion
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• v.15 no.3
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• pp.25-31
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• 2010

Combined technique of burner and DOC has been used for regeneration of Diesel Particulate Filter. Experiments has been performed to increase the temperature of engine exhaust gas to burn the collected soot in DPF at all conditions of operation of 3 liter diesel engine. Ignition temperature of soot can be successfully obtained by heats of burner flame and residual fuel oxidation at diesel oxidation catalyst even in the condition of oxygen deficiency. It is found that the load of air compressor and heat loss can be reduced to the level of practical application. It is also found that CO and THC emissions are not increase by additional combustion of regeneration burner.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.1013-1018
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• 2008

Vortex Inertial Staged Air (VIStA) burner for an once-through type boiler has been restored to the original premixed type to reduce nitrogen oxide (NOx) emission. The premixed version yields additional de-NOx effect by 20 ppm. The flame is formed closer to the wall at the 1st stage combustion chamber compared with the non-premixed one. The combustion characteristics are more sensitive to the air distribution for the premixed type, which necessitates proper optimization.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.18 no.6
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• pp.690-696
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• 2009

This paper introduces the automatic fine Bituminous Coal injection lance position control method using flame image process. The fine Coal injection lance is used to supply additional heat into the furnace in Mill plant. It injects fine coal into high pressured air flow and produces very heated and high pressured flame. For the such high temperature and pressure, the fine coal injection lance effects not only efficiency of burner but also furnace abrasion. To keep efficient combustion status and to avoid the abrasion, in this paper, the flame is monitored by computer image process. This paper proposes the flame image process method and lance position control according to calculated result for flame image process.

• Journal of the Korean Society of Combustion
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• v.1 no.2
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• pp.51-58
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• 1996

The coherent flamelet model(CFM) is applied to symmetric counterflow turbulent premixed flames. The flame source term is set proportional to the turbulence intensity to reproduce the experimental correlation of Abdel-Gayed et al. for the turbulent burning velocity. Flame quenching by the turbulent rate of strain is modeled by an additional multiplication factor to the flame source term. A modified form of CFM is employed to consider coexistence of burned and unburned premixture with ambient air. The predicted flame position and turbulent flow field coincide well with the experimental data of Kostiuk et al., although there is some discrepancy in the radial rms velocity component and integral length scale near the symmetric plane.

• Journal of the Korea Safety Management & Science
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• v.21 no.2
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• pp.1-8
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• 2019

Most of gas turbine combined cycle power plants are located in urban areas to provide peak load and district heating. However, NOx(nitrogen oxides) of exhaust gas emission from the power plants cause additional fine dust and thus it has negative impact on the urban environment. Although DLN(dry low NOx) and multi-stage combustors have been widely applied to solve this problem, they have another critical problem of damages to combustors and turbine components due to combustion dynamic pressure. In this study, the effect of different fuel ratio on NOx emission and pressure fluctuation was investigated regarding two variable conditions; combustor stages and power output on M501J gas turbine.

• 한국연소학회:학술대회논문집
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• 2002.06a
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• pp.123-132
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• 2002

A numerical study was conducted to investigate the combustion phenomena of normal start and unstart processes based on ISL's RAMAC 30 experiments with different diluent amounts and fill pressures in a ram accelerator. The initial projectile launching speed was 1.8 km/s which corresponded to the superdetonative speed of the stoichiometric $H_2/O_2$ mixture diluted with 5 $CO_2$ or 4 $CO_2$. Experiments with same condition except for projectile surface material demonstrated that ignition was successful with an aluminum projectile, but no combustion was observed in case of a steel projectile. In this study, it was found that neither shock nor viscous heating was sufficient to ignite the mixture at a low speed of 1.8 km/s, as was found in the experiments using a steel projectile. However, we could succeed in igniting the mixtures by imposing a minimal amount of additional heat to the combustor section and simulate the normal start and unstart processes found in the experiments with an aluminum projectile. For the numerical simulation of supersonic combustion, multi-species Navier-Stokes equations coupled with a Baldwin-Lomax turbulence model and detailed chemistry reaction equations of $H_2/O_2/CO_2$ suitable for high-pressure gaseous combustion were considered. The governing equations were discretized by a high order accurate upwind scheme and solved in a fully coupled manner with a fully implicit, time accurate integration method. The numerical results matched almost exactly to the experimental results. As a result, it was found that the normal start and unstart processes depended on the strength of gas mixture, development of shock-induced combustion wave stabilized by the first separation bubble, and its size and location.

• Journal of Biosystems Engineering
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• v.38 no.4
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• pp.306-311
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• 2013

Purpose: With the ever-rising energy prices, thermal energy heavily consuming facilities of the agricultural sector such as commercialized greenhouses and large-scale Rice Processing Complexes (RPCs) need to cut down their energy cost if they must run profitable businesses continually. One possible way to reduce their energy cost is to utilize combustible agricultural by-products or low-price oil instead of light oil as the fuel for their boiler systems. This study aims to analyze the heavy oil combustion characteristics of a newly developed hot water boiler system that can use both rice husk and heavy oil as its fuel convertibly. Methods: Heavy oil combustion experiments were conducted in this study employing four fuel feed rates (7.6, 8.5, 9.5, 11.4 $l/h$) at a combustion furnace vacuum pressure of 500 Pa and with four combustion furnace vacuum pressures (375, 500, 625, 750 Pa) at fuel feed rates of 9.5 and 11.4 $l/h$. Temperatures at five locations inside the combustion furnace and 20 additional locations throughout the whole hot water boiler system were measured to ascertain the combustion characteristics of the heavy oil. From the temperature measurement data, the thermal efficiency of the system was calculated. Flue gas smoke density and concentrations of air-polluting components in the flue gas were also measured by a gas analyzer. Results: As the fuel feed rate or combustion furnace vacuum pressure increased, the average temperature in the combustion furnace decreased but the thermal efficiency of the system showed no distinctive change. On the other hand, the thermal efficiency of the system was inversely proportionally to the vacuum level in the furnace. For all experimental conditions, the thermal efficiency remained in the range of 80.1-89.6%. The CO concentration in the flue gas was negligibly low. The NO and $SO_2$ concentration as well as the smoke density met the legal requirements. Conclusions: Considering the combustion temperature characteristics, thermal efficiency, and flue gas composition, the optimal combustion condition of the system seemed to be either the fuel feed rate of 9.5 $l/h$ with a combustion furnace vacuum pressure of 375 Pa or a fuel feed rate of 11.4 $l/h$ with a furnace vacuum pressure between 500 Pa and 625 Pa.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.863-866
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• 2011

Recently environmental issue is more and more emphasized and 'Green Growth' became on of the key words of this Government. Based on this trend, the exhaust gases out of the gas generator cycle and the staged combustion cycle LRE whose propellants are kerosene and LOx were compared. For this purse, 8 tonf class of each cycle engine was designed and the amount and the components of the gases were investigated by using CEA. As expected, the staged combustion cycle engine generates less pollutants than the other cycle. In addition, the graphite that is generated by the gas generator can be reacted with the oxygen in the atmosphere creating additional pollutants.

• Journal of the Korean Society of Combustion
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• v.15 no.2
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• pp.1-11
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• 2010

Power generation systems based on the oxy-coal combustion with carbon dioxide capture and storage (CCS) capability are being proposed and discussed lately. Although a large number of lab scale studies for oxy-coal power plant have been made, studies of pilot scale or commercial scale power plant are not enough. Only a few demonstration projects for oxy-coal power plant are publicized recently. The proposed systems are evolving and various alternatives are to be comparatively evaluated. This paper presents a proposed approach for performance evaluation of a commercial 100 MWe class power plant, which is currently being considered for 'retrofitting' for the demonstration of the concept. The system is configurated based on design and operating conditions with proper assumptions. System components to be included in the discussion are listed. Evaluation criteria in terms of performance are summarized based on the system heat and mass balance and simple performance parameters, such as the fuel to power efficiency and brief introduction of the second law analysis. Also, gas composition is identified for additional analysis to impurities in the system including the purity of oxygen and unwanted gaseous components of nitrogen, argon and oxygen in air separation unit and $CO_2$ processing unit.

• Journal of the Korean Society of Combustion
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• v.11 no.2
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• pp.1-6
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• 2006

This report presents a study of the development of an advanced coal nozzle used in burners to reduce unburned carbon (UBC) in a tangential coal-fired boiler. To understand the mechanism of UBC reduction, experiments using conventional burners were carried out to evaluate the effects of air injection velocity, coal fineness and over fired air (OFA) on combustion efficiency. It was confirmed that ignition of pulverized coal particles close to the burner is helpful toward the complete burn of residual carbon in fly ash. These efforts indicated the additional results that UBC was strongly dependent on the primary air velocity and coal fineness; especially that UBC dramatically decreased when the weight fraction of pulverized coal under $75{\mu}m$ was over 85 %. New coal nozzles, modified from conventional nozzles, were prepared and tested to improve the combustion efficiency. Some of these nozzles offered relatively lower unburned carbon than those of conventional burners and are referred to as HPFS (High Performance Flame Stability) coal nozzles.