• Journal of Energy Engineering
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• v.6 no.1
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• pp.96-103
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• 1997

Coal gasification experiments were performed to characterize the bench scaled unit of 0.5∼1.0 T/D entrained coal gasifier developed by KIER. Datong coal from China was selected for this study. The system was operated at the temperature range of 1300∼1550$^{\circ}C$, with 62.5% of coal water mixture on the basis of dry coal. Oxygen and slurry mixture were preheated prior to feeding into burner and the ratio of oxygen/coal was in the range of 0.8∼1.2. In the preparation of coal water mixture, 0.3 wt% of CWM1002 and 0.05 wt% of NaOH wire added to reduce viscosity as well as to enhance theological properties of slurry. The resultant gaseous products consist primarily of hydrogen, carbon monoxide, carbon dioxide, and minor amounts of methane. Formation of H$_2$and CO was increased, while CO$_2$was decreased as the reacting temperature being increased due to the char-CO$_2$reaction. Maximum production of H$_2$and CO occurred in the O$_2$/coal ratio of 0.9 at 1530$^{\circ}C$. Heating values of product gases were in the range of 1700∼2400 kcal/N㎥.

• Journal of Energy Engineering
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• v.23 no.4
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• pp.207-214
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• 2014

With the depletion of high grade coal, it is indispensable to be used co-combustion of low rank coal with bituminous coal in pulverized coal-fired power plants. This study describes the detailed measurements of combustion characteristics of bituminous and subbituminous coal in a 0.7MWth pilot-scale test facility. This experimental works include the measurement of gas temperature, gas concentrations along with the reactor axial and radial distance at the condition of excess air ratio of 1.2. The solid sampling was carried out and analyzed with the combustion of bituminous coal. The main reaction zone of coal flame in a reactor was formed about 1 m from the swirl burner, and at downstream, the fully developed temperature and species distribution was observed. The sampled particles of bituminous coal in a reactor revealed the complete carbon burn-out was achieved just after an main combustion zone.

• 한국신재생에너지학회:학술대회논문집
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• 2011.11a
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• pp.74.2-74.2
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• 2011

석탄가스화 기술은 고온, 고압 조건에서 석탄과 산소의 불완전연소 및 가스화 반응을 통해 일산화탄소(CO)와 수소($H_2$)가 주성분인 합성가스를 제조하여 이용하는 현실적인 에너지원의 확보를 위한 방법인 동시에 이산화탄소를 저감할 수 있는 기술이다. 석탄가스화기 공급되는 석탄은 산소와의 부분 산화, 수증기 및 $CO_2$와의 반응에 의하여 합성가스로 전환되는데, 일반적으로 슬래깅 방식 석탄가스화기의 정상운전 중에 가스화기 내부 온도는 $1,400{\sim}1,600^{\circ}C$ 정도의 고온이며, 운전압력은 20~60 기압으로 매우 고압 상태에서 운전이 이루어지는데, 공급되는 석탄 시료의 성분들 중 가연성 물질의 99% 이상이 합성가스로 전환되는 반면, 회분에 해당되는 무기물의 대부분은 용융 슬랙 형태로 가스화기의 벽을 타고 흘러내리다가 슬랙탭을 통해 하부의 냉각조로 떨어지면서 급냉이 이루어지게 된다. 그러므로, 석탄가스화기 정상운전중 슬랙탭 주변의 온도를 고온으로 유지함으로써 용융슬랙의 고형화를 방지하는 것은 석탄가스화기의 안정적인 연속운전을 위하여 중요한 기술 중의 하나라고 할 수 있다. 따라서, 본 연구에서는 저급탄 가스화를 위한 1 톤/일급 고온, 고압 습식 석탄가스화기의 정상운전중 슬랙탭 부근에서 용융슬랙의 고형화를 방지하기 위한 슬랙탭 버너시스템의 설계를 진행하였으며, 안정적인 운전조건 도출을 위하여 보조연료(CNG)와 산소의 공급비율에 따른 화염특성 시험을 진행하였다.

• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.353-355
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• 2008

최근 석탄 가스화 기술은 화석연료인 석탄을 기존의 공해물질 발생을 90%이상 줄이면서 고효율로 활용할 수 있는 방법으로 각광받고 있다. 본 연구는 습식 석탄 가스화기에서 가스화의 핵심적인 요소인 버너의 분무 관계 분야에 대한 분무 특성 및 무화성능을 높일 수 있는 분무기의 구조 및 운전 조건 등을 제시 할 목적으로 분무 시 내부를 관찰 할 수 있는 아크릴을 이용하여 내부 혼합식 버너를 제작하였다. 미립화 특성을 파악하기 위하여 $O_2$/Fuel Ratio 및 버너의 내부 혼합 방식, 분사각도, 각 분사 높이에 따른 미립화 특성을 관찰하였으며, 입도 분석은 심파텍사의 입도 분석기를 이용하여 측정하였다. 내부 혼합식 버너의 입도는 분사 각도와 $O_2$/Fuel Ratio에 따라서 변화하는 경향을 나타냈으며, 공급되어지는 Fuel은 석탄 슬러리와 물을 이용하여 각각의 입도를 측정하였다. slurry의 공급량이 고정된 상태에서 산소 공급량이 증가함에 따라 미립화도는 증가하는 경향을 나타내었으며, 슬러리 공급량과 산소 공급량이 동일한 경우 버너의 분사 각도에 따라 미립화도가 다르게 나타나는 특성을 관찰하였다.

• 한국연소학회:학술대회논문집
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• 2012.04a
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• pp.177-179
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• 2012

This work presents an experimental investigation to study $NO_x$ emissions under stoichiometric air ratio and elevated pressure (2~10bar) in a High Press Combustor(HPC) equiped with double cone burner which was designed by Pusan Clean Coal Center(PC3). Exaust gas temperature and $NO_x$ emissions were measured at the end of the combustion chamber. The $OH^*$ radical concentration and $NO_x$ emission were decreased as a function of increasing ${\lambda}$ generally. On the other hand, $OH^*$ radical concentration and $NO_x$ emission increased with ${\lambda}$ pressure of the combustion chamber. $NO_x$ emissions which were governed by thermal $NO_x$, were highly increased under the elevated pressure, but slightly increased at sufficiently low fuel concentrations (${\lambda}>2.0$).

• Journal of the Korean institute of surface engineering
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• v.42 no.3
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• pp.139-144
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• 2009

A microwave plasma torch at the atmospheric pressure by making use of magnetrons operated at the 2.45 GHz and used in a home microwave oven has been developed. This electrodeless torch can be used to various areas, including industrial, environmental and military applications. Although the microwave plasma torch has many applications, we in the present work focused on the microwave plasma torch operated in pure steam and several applications, which may be used in future and right now. For example, a high-temperature steam microwave plasma torch may have a potential application of the hydrocarbon fuel reforming at one atmospheric pressure. Moreover, the radicals including hydrogen, oxygen and hydroxide molecules are abundantly available in the steam torch, dramatically enhancing the reaction speed. Also, the microwave plasma torch can be used as a high-temperature, large-volume plasma burner by injecting hydrocarbon fuels in gas, liquid, and solid into the plasma flame. Finally, we briefly report treatment of soils contaminated with oils, volatile organic compounds, heavy metals, etc., which is an underway research in our group.

• Transactions of the Korean hydrogen and new energy society
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• v.23 no.5
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• pp.493-502
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• 2012

Syngas laminar burning velocity measurements were carried out at atmospheric pressure and ambient temperature using the Bunsen flame configuration with nozzle burner as a fundamental study on flame stability of syngas fuel. Representative syngas mixture compositions ($H_2$:CO) such as 25:75%, 50:50% and 75:25% and equivalence ratios from 0.5 to 1.4 have been conducted. Average laminar burning velocities have been determined by the stabilized nozzle burner flames using the angle method, radical surface area method and compared with the data obtained from the other literatures. And the results of each experimental methodologies in the various composition ratios and equivalence ratios were coincided with the result of numerical simulation. Especially, it was confirmed that there was necessary to choice a more accurate measurement methodology even the same static flame method for the various composition ratios of syngas fuel including hydrogen. Also, it was reconfirmed that the laminar burning velocities gradually increased with the increasing of hydrogen content in a fuel mixture.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 1999.11a
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• pp.23-29
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• 1999

Experimental studies are conducted to investigate the flame stability and the thermal/fuel NOx formation characteristics of the low calorific value (LCV) coal derived gas fuel. Synthetic LCV fuel gas is produced by mixing carbon monoxide, hydrogen, nitrogen and ammonia on the basis that the thermal input of the syngas fuel into a burner is identical to that of natural gas. The syngas mixture is fed to and burnt with air on flat flame burner. With the variation of the equivalence ratio for specific syngas fuel, flame behaviors are observed to identify the flame instability due to blow-off or flashback and to define stable combustion range. Measurements of NOx content in combustion gas are made for comparing thermal and fuel NOx from the LCV syngas combustion with those of the natural gas one. In addition, the nitrogen dilution of the LCV syngas is preliminarily attempted as a NOx reduction technique, and its effects on thermal and fuel NOx production are discussed.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.3
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• pp.251-257
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• 2012

This work presents an experimental investigation of NOx emissions according to inlet air temperature (550-660 K), stoichiometric air ratio (${\lambda}$, 1.4-2.1), and elevated pressure (2-5 bar) in a High Press Combustor (HPC) equipped with a double cone burner, which was designed by Pusan Clean Coal Center (PC3). The exhaust-gas temperature and NOx emissions were measured at the end of the combustion chamber. The NOx emissions generally decreased as a function of increasing ${\lambda}$. On the other hand, NOx emissions were influenced by ${\lambda}$, inlet air temperature and pressure of the combustion chamber. In particular, when the inlet air temperature increased, the flammability limit was extended to leaner conditions. As a result, a higher adiabatic temperature and lower NOx emissions could be achieved under these operation conditions. The NOx emissions that were governed by thermal NOx were greatly increased under elevated pressures, and slightly increased at sufficiently low fuel concentrations (${\lambda}$ >1.8).

• Journal of Korean Society of Environmental Engineers
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• v.28 no.10
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• pp.1065-1073
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• 2006

The unturned carbon in fly ash, recently occurred in the coal-fired Yong Hung power station, caused some problems in ash utilization and boiler efficiency. This paper describes the analysis of unburned carbon and six coals, some tests performed at Yong Hung Boiler, and the results of combustion modification for the reduction of unburned carbon in fly ash. From the physical and chemical analysis of unburned carbon in fly ash, most particles were turned out to be hollow cenosphere and agglomerated soot particles. The sooting potential from six coals used in the plant were investigated with CPD(Chemical Percolation Devolatilization) model. The results showed that the higher potential was presented to Peabody, Arthur, Shenhua coals rather than other coals. It was necessary to measure the coal flow rates at each coal feeding pipe for four burner levels since they affect the extent of mixing of soot with oxidant, in turn, the oxidation rate of soot particles. The unbalance in coal flow rate was found in several coal pipes. We successfully reduced unturned carbon in ash by increasing the excess air and changing the SOFA's yaw angle.