• Plant Journal
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• v.9 no.2
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• pp.12-18
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• 2013

• Clean Technology
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• v.26 no.3
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• pp.211-220
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• 2020

This experimental study investigates the design parameters to achieve ultra low NOx combustion of coal using a 80 kW capacity single-burner furnace. The influence of key design parameters such as SN, overall and burner-zone equivalence ratios, primary/secondary air ratio, overfire air (OFA) ratio were tested for a total of 81 cases. The results showed that weak swirl intensity of the burner leads to higher NOx emission whereas strong swirl intensity accompanies increased CO concentration desipte lower NOx emission. Therefore, finding an appropirate swirl intensity is essential for the burner design. Larger flow rate of secondary air increased NOx emission, whereas smaller flow rate stretches the flame and increased CO emission. The lowest NOx emission of 82 ppm (6% O₂) was achieved at the optimal condition of the present burner deisgn. It is expected to furrther lower the NOx emission by introducing splitting the burner secondary air into three or four streams.

• Journal of Energy Engineering
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• v.22 no.2
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• pp.96-104
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• 2013

Coal gasification is considered as one of the best alternatives among clean coal technology and new concept next generation technologies are under being developed to achieve low cost as well as high efficiency. In this study we have developed double swirl multi-burner as part of the development of low cost compact gasifier. We installed new concept multi-burner with pulverized coal distributor to the body of existing gasifier for burner test. Gasification test was performed under the condition of $6.4{\sim}7.2kg/cm^2$ and $1170{\sim}1300^{\circ}C$ by using Indonesian ABK (sub-bituminous) coal to get operation condition of new concept multi-burner. Our interest was focused to ensure a stable operating condition rather than the gasifier performance evaluation. As a result, we were able to achieve the carbon conversion of 84% and the cold gas efficiency of 52.1% at the stable operating conditions.

• Proceedings of the KSME Conference
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• 2001.11b
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• pp.102-105
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• 2001

Numerical simulations of coal combustion were carried out to identify what kind of burner design parameters are affecting the NOx emission. Where used burner design parameters are primary air velocity, secondary air velocity, $2^{nd}/3^{rd}$ air ratio, tertiary air velocity, and tertiary air injection location. Taguchi method was used to find the effective burner design parameters related to NOx formation. The results of numerical simulations showed that secondary air velocity and $2^{nd}/3^{rd}$ air ratio was the key parameters reducing the NOx emission. The total number of simulation cases was reduced by Taguchi method.

• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.78.1-78.1
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• 2011

분포지역과 매장량이 한정되어 있는 석유에 비하여 석탄은 가채년수가 길고 세계 전역에 널리 분포되어 있으므로 향후 안정적인 에너지 공급으로 각광받고 있다. 석탄을 이용하여 CWM을 제조하는 기술은 석유에 비하여 저장, 수송, 분진 비산등의 문제점을 개선하여 위하여 1980년대부터 석탄 물 혼 합연료(Coal-Water Mixture)의 기술개발을 위한 연구가 진행되었다. 이는 미분탄(유연탄)에 30%정도의 물과 약간의 첨가제를 혼합하여 유체화하여 수송성은 액체연료와 같고 연소성은 석탄의 성상을 갖는 특징을 가지게 된다. 본 연구에서는 당센터에서 보유하고 있는 습식 분류층 가스화장치에 적용하기 위한 CWM(Coal Water Mixture)제조 특성을 연구하였다. 습식 석탄 가스화기에 사용되는 CWM은 미분되어진 석탄과 물, 첨가제를 일정비율로 혼합하여 사용하게 된다. 이때 공급되어지는 미분의 입도와 분쇄 형태에 따른 입자 형태, 입자의 분포에 따라서 CWM의 특성이 각각 다르게 나타나게 된다. 이때 만들어진 CWM의 농도와 점도 특성에 따라서 버너의 성능 및 가스화기 운전 조건등에 많은 영향을 미치게 된다. 습식 석탄 가스화에 적용된 예정인 대상탄을 대상으로 하여 석탄분쇄 형태에 따른 CWM의 제조 특성을 실험하였다.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.5
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• pp.491-501
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• 2011

We performed numerical simulation using a DPM (discrete phase model) to identify the optimal operation ranges in two representative PM burners widely used in domestic 500-MW pulverized coal-fired power plants. Recently there has been an increased utilization of low-cost coals such as sub-bituminous coal. We investigate the effects of coal blends on the distribution ratio of coal to air by varying the mass flow rates of pulverized coal and primary air and the particle size. We present and discuss optimal conditions for the distribution ratio of coal to air in PM burners.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.9
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• pp.939-946
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• 2011

In thermal power generation companies, the recycling of refined ash (LOI < 6%) obtained from a PC-firing furnace is beneficial for the companies, e.g., it can be used for making lightweight aggregates. However, ash having a high LOI, which cannot be reused, is still buried in the ground. To obtain refined ash, the re-burning of high-LOI ash (LOI > 6%) in a PC-firing furnace can be an alternative. In this study, a numerical analysis was performed to demonstrate the effects of ash re-burning. An experimental constant value was decided by TGA (thermo-gravimetric analysis), and a DTF (drop-tube furnace) was used in the experiment for calculating the combustion of ash. On the basis of the trajectory of the moving particles of coal and ash, it was concluded that supplying ash near the burner, which is located high above the ground, is appropriate. On the basis of numerical results, it was concluded that an ash supply rate of 6 ton/h is suitable for combustion, without affecting the PC-firing boiler.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.04a
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• pp.453-456
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• 2011

An experimental investigation of the heat transfer characteristics of stretched premixed flames using Synthetic gas has been performed. Hydrogen and carbon mon-oxide which could be extracted from coal gasification process are the main fuel of synthetic-gas. Heat flux at the stagnation point was increased as global strainrate was increased, then the heat flux was decreased when a global strainrate reached a sudden point. Heat flux at the stagnation point is also affected by nozzle to impingement distance. Heat flux was increased as nozzle to impingement place distance was increased. This study is a foundation study of practical use of secondary gases from coals.

• 한국신재생에너지학회:학술대회논문집
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• 2011.11a
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• pp.71.1-71.1
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• 2011

석석탄가스화 기술은 고온, 고압 조건에서 미분탄과 산소의 가스화 반응에 의해 CO와 $H_2$가 주성분인 합성가스를 제조하는 기술로서 차세대 화력발전 뿐만아니라 다양한 화학원료 제조를 위한 분야에서 각광을 받고 있다. 또한, 가스화 기술은 향후 CCS기술, CTL(Coal To Liquid, 석탄액화)기술, SNG(Synthetic Natural Gas, 합성천연가스)생산, 수소생산, 각종 화학원료 생산 등과 연계가 가능한 미래 석탄이용 분야의 핵심 기술이라 할 수 있다. 따라서, 고등기술연구원에서는 이러한 석탄가스화를 통해 양질의 합성가스를 제조하기 위한 기술 개발의 일환으로 pilot급 고온, 고압 건식 분류층 가스화기, 기류수송 방식의 미분탄공급장치, 수냉자켓 구조의 합성가스 냉각장치, 합성가스 중 분진제거를 위한 금속필터 장착 집진장치 등을 연계하여 20기압의 고압 조건에서 장시간 연속운전을 진행하였다. 본 연구에서는 미분탄 공급을 위하여 상부공급 버너를 적용하였고 석탄가스화기는 $1,300{\sim}1,350^{\circ}C$ 정도의 온도에서 운전을 진행하였으며 미분탄을 75 kg/h의 조건에서 연속적으로 공급하였다. 그리고, 이러한 조건에서 5.5일 정도의 연속운전을 진행하는 동안 CO 44~48%, $H_2$ 20~21%, $CO_2$ 4~5% 조성의 석탄 합성가스를 $200Nm^3/h$ 안정적으로 제조할 수 있었다.

• Journal of Energy Engineering
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• v.26 no.4
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• pp.118-126
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• 2017

This study was performed to investigate the characteristics of combustion and emissions in pulverized coal fired boiler for using high moisture coal and dry coal through computational fluid dynamics(CFD). We validated this boiler model with performance data of the boiler. The results of flow characteristics showed that climbing speed of gases was increased as blending ratio of high moisture coal was increased. It can decrease a residence time of fuel in the furnace. And it influence coal combustion. The coal burnout and NOx generation in burner level were decreased as increasing blending ratio of high moisture coal. The gas temperature and NOx formation were increased after OFA level due to coal burnout delay.