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O₂/CO₂조건과 O₂/N₂조건에서의 촤 연소특성 및 산화 반응성에 관한 실험적 연구
김성곤(Song Gon Kim),이천성(Cheon Seong Lee),이병화(Byoung Hwa Lee),송주헌(Ju Hun Song),장영준(Young June Chang),전충환(Chung Hwan Jeon) 대한기계학회 2010 大韓機械學會論文集B Vol.34 No.12
본 연구에서는 촤 연소 시에 분위기 가스 변화에 따른 연소 반응 변화를 수직 관형 연소로를 이용하여 실험적으로 측정해 보았다. 실험 조건으로 아역청탄인 Adaro탄과 역청탄인 Coal valley탄을 사용하였고, 두 탄을 O₂/CO₂조건과 O₂/N₂조건에서 온도를 900, 1100, 1300℃, 산소 분압을 12, 21, 30%로 변화를 주어 촤 반응성 실험을 수행하였다. 순산소 조건과 일반 대기 조건을 비교하였을 경우 순산소 조건일 때 입자온도와 총괄 반응량이 낮게 나타나는 경향을 보였지만, 입자 표면에서의 반응률을 계산한 결과, 분위기 가스의 영향과 상관없이 거의 동일한 경향을 가지는 것으로 나타났다. 또한 두 조건에서의 촤 연소 반응을 위한 반응 속도 상수 및 활성화 에너지 역시 분위기 가스의 영향과 상관없이 유사한 값을 가지는 것으로 확인하였다. 전반적으로 Adaro탄이 Coal valley탄보다 입자 온도와 총괄 반응량이 높게 나타났다. We investigated the combustion rate and kinetic rate of char when burning in oxygen-enriched atmospheres with either an N2 or CO₂ bath gas in a drop tube furnace. The experiments were performed with sub-bituminous coal (Adaro) and bituminous coal (Coal valley) under atmospheric pressure conditions. Two different coals were investigated over 12 to 30 vol% oxygen and furnace temperatures of 900, 1100, and 1300℃. For both coals, the particle temperature and overall reaction rate are lower in the CO₂ bath gas. However, analysis of single-particle data shows that the surface-specific burning rate of char oxidation is similar in both gases. In addition, the kinetic rate and activation energy for each coal were similar for both gases. Generally, the particle temperature and overall reaction rate of sub-bituminous coal are higher than those of bituminous coal.
DTF를 이용한 미분탄 연소에서 연료비와 온도가 NOx 배출에 미치는 영향
김성곤(Song-gon Kim),이천성(Cheon-seong Lee),이병화(Byoung-hwa Lee),송주헌(Ju-hun Song),전충환(Chung-hwan Jeon),장영준(Young-june Chang) 대한기계학회 2009 대한기계학회 춘추학술대회 Vol.2009 No.11
An experimental investigation on NOx emission emitted from a combustion of pulverized coals was carried out in a drop tube furnace apparatus. The tested three coals have different fuel ratios ranging from 1.65 to 3.54 to examine effect of volatile matter on NOx emission in the coals. The temperature independently varies from 800℃ to 1300℃ under oxygen concentration 16.9% to investigate the NO emission from Wira (sub-bituminous coal) and Yakutugol (bituminous coal). NO concentration were obtained to be used for kinetic analysis. The results show that the conversion ratio of fuel bound nitrogen to NOx concentration linearly increases with changes in the fuel ratio. A first order kinetic model was applied to the evolution of NO. The model shows the activation energy for the NO emission from Wira is 24.378kcal/mol and Yakutugol is 41.879kcal/mol.
CO,CO2 배출량 측정을 통한 아 역청탄 촤 산화 반응률에 관한 실험적 연구
강기태(Ki Tae Kang),송주헌(Ju Hun Song),이천성,장영준(Young June Chang),전충환(Chung Hwan Jeon) 대한기계학회 2009 대한기계학회 춘추학술대회 Vol.2009 No.11
A fundamental investigation has been conducted on the combustion of single particle of a sub-bituminous coal char burning at different temperatures and oxygen concentrations(6%, 10%). The lab-scale test setup consisted of a drop tube furnace where gas temperatures ranged from 900℃ to 1300℃. A calibrated two color pyrometer, mounted on the top of the furnace, provided temperature profiles of luminous particle during a char oxidation. An amount of char mass reacted during char oxidation is measured with thermogravimetry analyzer by using an ash tracer method and is measured with FT-IR by using gas quantitative analysis method. Two methods are compared with each other. Finally, mass and area reactivity as well as reaction rate coefficients are determined for char burning at atmospheric pressure condition.
남동현(Dong-hyun Nam),송주헌(Ju-Hun Song),장영준(Young-June Jang),전충환(Chung-Hwan Jeon) 대한기계학회 2010 대한기계학회 춘추학술대회 Vol.2010 No.5
This study is to investigate a flame structure and NOx emission on lean partially premixed gas turbine. The experiments were conducted to estimate the effect of fuel temperature (293, 313, 333K) at dump combustor inlet. The equivalence ratio was ranging from 0.55 to 0.85. This paper show that NOx emission was increased when concentration of OH radical is increased in same equivalence ratio. Finally, as fuel temperature increasing, NOx emissions was decreased on lean conditions
500㎿급 아역청탄 전소 보일러의 NOx 배출저감에 미치는 SOFA 영향에 관한 연구
강기태(Ki-Tae Kang),송주헌(Ju-Hun Song),윤민지(Min-Ji Yoon),이병화(Byoung-Hwa Lee),김승모(Seung-Mo Kim),장영준(Young-June Chang),전충환(Chung-Hwan Jeon) 대한기계학회 2009 大韓機械學會論文集B Vol.33 No.11
A numerical investigation has been carried out about the performance of a 500MW class tangentially coal-fired boiler, focusing on the optimization of separated overfire air (SOFA) position to reduce NOx emission. For this purpose, a comprehensive combination of NOx chemistry models has been employed in the numerical simulation of a particle-laden flow along with solid fuel combustion and heat and mass transfer. A reasonable agreement has been shown in baseline cases for predicted operational parameters compared with experimental data measured in the boiler. A further SOFA calculation has been made to obtain optimum elevation and position of SOFA port. Additionally, clarifying on the effect of SOFA on NOx emission has been carried out in the coal-fired boiler. As a result, this paper is valuable to provide an information about the optimum position of SOFA and the mechanism by which the SOFA would affect NOx emission.
제품속성의 정렬 가능성과 확실성이 제품 선호도에 미치는 영향
김수영 ( Soo Young Kim ),송주헌 ( Ju Hun Song ),손영우 ( Young Woo Sohn ) 한국감성과학회 2008 감성과학 Vol.11 No.2
Products can maintain a high level of market share for many years by succeeding early in the development of a market. To overcome the benefit of pioneering a market, late entrants to the market can use differentiation strategies: developing novel attributes or enhancing preexisted attributes. In general, preexisted attributes are more memorable, but novel attributes can be weighted as heavily as preexisted attributes by contextual constraints. Based on the research of appraisal-congruent judgement, certainty appraisal dimension may affect the degree to which people engage in systematic or heuristic processing. This study examines the effects of alignability (the ease with which the attributes of one object can be aligned or mapped onto another object) of product attributes and certainty on consumer preferences for late entrants. Participants were induced to experience certainty and then completed a questionnaire. As predicted, participants induced certainty were likely to engage in heuristic processing, while participants induced uncertainty were likely to engage in systematic processing. This study provides an implication that companies should additionally consider consumers` feeling of certainty when launching a new brand.
황민영,김용균,전충환,송주헌,김용태,장윤한,Hwang, Min-Young,Kim, Yong-Gyun,Jeon, Chung-Hwan,Song, Ju-Hun,Kim, Yong-Tae,Chang, Youn-Han 한국전기화학회 2009 한국전기화학회지 Vol.12 No.2
리튬 2차전지는 휴대용 전자기기의 전원으로 사용되어 왔다. 최근 하이브리드 자동차, 전기자동차의 에너지 저장매체로써 적용으로 인해 시장 확대가 기대되고 있다. 양극 활물질은 리튬2차전지의 성능, 수명, 용량을 결정하는 물질이며, 급증하는 시장의 수요에 따라 양극 활물질을 대량으로 생산할 수 있는 기술을 개발하는 것이 시급하다. 본 연구에서 실제 양극 활물질($LiCoO_2$) 생산라인에서 가동 중인 소성로를 3D 모델링하였고, 수치적 해석을 통해 소성로 내부의 온도와 유동의 방향, 화학적 거동을 밝혀내었다. 결과로써, 생산량 증가로 인해 소성로에서 생성되는 $CO_2$ 농도가 증가하며 정체되는 지점을 확인하였고, TGA-DSC 실험을 통해 $CO_2$가 몰분율 15%이상에선 $LiCoO_2$의 적절한 형성에 영향을 주는 현상을 확인하였다. 또한 소성로의 형상변화와 공정조건의 변화를 통해 문제되는 $CO_2$를 원활히 배출할 수 있는 해결책을 제안하였다. Lithium secondary batteries have been widely used in the portable electric devices as power source. Recently it is expected that the realm of its applications expands to the markets such as energy storage medium of hybrid electric vehicle(HEV), electric vehicle(EV). Cathode active material is crucial in terms of performance, durability, capacity of lithium secondary batteries. It is urgent to develope the technology for mass production of cathode material to cope with the markets' demands in the near future. In this study, a calcination furnace running in real production line is modelled in 3D, and the thermal flow and gas flow after chemical reaction in the furnace is analyzed through numerical computations. Based on the results, it is shown that large volume of $CO_2$ gas is generated from chemical reaction. High concentration of $CO_2$ gas and it's stagnation is clearly found from the reactant containers in which the reaction occur to the bottom area of the furnace. It is also studied that 15% or more $CO_2$ mol fraction could affect to proper formation of $LiCoO_2$ through TGA-DSC analysis. The solutions to evacuate carbon dioxide from the furnace are suggested through the change of furnace design and operating condition as well.
DAEM 분석 방법을 통한 국내 수입탄의 탈휘발화 반응특성에 관한 실험적 연구
김량균(Ryang Gyoon Kim),송주헌(Ju Hun Song),장영준(Young June Chang),전충환(Chung Hwan Jeon) 대한기계학회 2009 대한기계학회 춘추학술대회 Vol.2009 No.11
The experiment was designed to study the pyrolysis kinetics of two different classes of coal. The pyrolysis behaviors of the coals were first observed with thermogravimetric analyzer(TGA). The kinetic analysis was further done based on a new distributed activation energy model(New DAEM). During the analysis, thermogravimetric curves measured at three different heating rates were used to obtain the activation energy distribution function curve ?(E) of a given coal sample where mean activation energy is determined by its peak. The results show a significant difference in the mean activation energy between two coals for the pyrolytic reaction.