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RISS 인기검색어
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- 저자 : 김용택 ( Yong Tack Kim ) (검색결과 8 건)
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가스분석을 이용한 석탄 입자크기가 촤-CO2 가스화 반응성에 미치는 영향 연구
김용택 ( Yong Tack Kim ),서동균 ( Dong Kyun Seo ),황정호 ( Jung Ho Hwang ) 한국화학공학회 2011 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.49 No.3
Char gasification is affected by operating conditions such as reaction temperature, reactants gas partial pressure, total system pressure and particle size in addition to chemical composition and physical structure of char. The aim of the present work was to characterize the effect of coal particle size on CO2 gasification of chars prepared from two different types of bituminous coals at different reaction temperatures(1,000~1,400℃). Lab scale experiments were carried out at atmospheric pressure in a fixed reactor where heat was supplied into a sample of char particles. When a flow of CO2(40vol%) was delivered into the reactor, the char reacted with CO2 and was transformed into CO. Carbon conversion of the char was measured using a real time gas analyzer having NDIR CO/CO2 sensor. The results showed that the gasification reactivity increased as the particle size decreased for a given temperature. The sensitivity of the reactivity to particle size became higher as the temperature increases. The size effects became remarkably prominent at higher temperatures and became a little prominent for lower reactivity coal. The particle size and coal type also affected reaction models. The shrinking core model described better for lower reactivity coal, whereas the volume reaction model described better for higher reactivity coal.
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김용택(Yong-tack Kim),서동균(Dong-Kyun Seo),황정호(Jung-Ho Hwang) 한국연소학회 2009 KOSCOSYMPOSIUM논문집 Vol.- No.39
The gasification reactivities of various coal chars with CO₂ were investigated in this experiment. Various coals from many countries around the world are used for pulverized coal boiler in power plants in Korea. Carbon conversion was measured using a real time gas analyzer with NDIR CO, CO₂ sensor. In a lab scale furnace, each coal sample was devolatilized in nitrogen atmosphere at 950℃ and became coal char and then more heated up at desired temperature. Each char was then gasified with CO₂ under isothermal conditions. The reactivities of coal chars was investigated at different temperatures and CO₂ concentrations. Non-reacted core model and Homogeneous model were used to interpret the experiment data. It was found that the gasification rate of various coals were very different and if the volatile matter content increased, the reaction rate increased. The experimental data could be well-described by the non-reacted core model and the homogeneous model if carbon conversion is under 0.98
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가스분석을 이용한 석탄 종류별 CO₂ 가스화 반응특성 연구
김용택(Yong-Tack Kim),서동균(Dong-Kyun Seo),황정호(Jung-Ho Hwang) 한국연소학회 2010 한국연소학회지 Vol.15 No.2
Various coals from many countries around the world have been used for pulverized coal boiler in power plants in Korea. In this study, the gasification reactivities of various coal chars with CO₂ were investigated. Carbon conversion was measured using a real time gas analyzer with NDIR CO/CO₂ sensor. In a lab scale furnace, each coal sample was devolatilized at 950℃ in nitrogen atmosphere and became coal char and then further heated up to reach to a desired temperature. Each char was then gasified with CO₂ under isothermal conditions. The reactivities of coal chars were investigated at different temperatures. The shrinking core model (SCM) and volume reaction model(VRM) were used to interpret the experiment data. It was found that the SCM and VRM could describe well the experimental results within the carbon conversion of 0-0.98. The gasification rates for various coals were very different. The gasification rate for any coal increased as the volatile matter content increased.
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김용택,김원극,오훈일 한국산업미생물학회 1995 한국미생물·생명공학회지 Vol.23 No.1
우리나라의 전통식품인 청국장과 일본의 전통 발효발효식품인 natto로부터 혈전용해 균주를 분리하여 혈전용해능을 조사한 결과 청국장에서 분리된 균주중에는 혈전용해능을 나타내지 않는 균주가 다수 포함되어 있으나, natto로부터 분리한 균주들은 대부분 혈전용해능을 나타내었다. 그러나 가장 우수한 혈전용해능을 나타내는 균주는 청국장에서 발견되었으며, 그 활성은 1.84 plasmin unit였다. 이 균주의 동정을 위하여 형태학적, 생화학적 특성을 조사한 결과 분리균주는 간균으로 운동성이 있고, 호기성(catalase 함유)으로 그람양성의 세균이었으며 포자를 형성하는 것으로 관찰되어 Bacillus 속에 속하는 미생물로 동정되었으므로 Bacillus sp. CK 11-4로 명명하였다. Bacterial strains showing the fibrinolytic activity were screened from Chungkook-jang and Natto (Japanese traditional soy food). The strains isolated from Natto revealed a high level of fibrinolytic activity, wherease nearly half of the isolates from Chungkook-jang did not show the relevant activity. However, one strain isolated from Chungkook-jang showed the highest fibrinolytic activity (1.84 plasmin unit), and subsequently identified as Bacillus species. The fiorinolytic strain was designated as Bacillus sp. CK 11-4.
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녹차 추출 방법에 따른 추출물 구취 제거 효과에 관한 연구
유재선,김용택,이윤수,권익부,신철수 대한구강보건학회 1991 大韓口腔保健學會誌 Vol.15 No.2
Green tea extracts, which contain flavonoids, were prepared by using various extraction methods and their effects reducing oral malodor were investigated. Flavonoids of green teas from different planting sites had seven same glycosides and five same aglycones, and their contents made no significant differences. Among the deodorants available commercially, that for toilet was much more effective than those for living room and car-interior. On the other hand, the chlorophylls and the tannins from green teas also had strong deodorant effects, but glycerine and water which were used as extracting solvent showed negligible effects. Four solvents showing no problem on food processing in Korea were used to get the extracts of green teas, and effects of those extracts on reducing a typical malodor, methyl mercaptan, were comparde via in vitro tests. The best extract was attained by using EtOH-water, and hot water(80℃), glycerine-water, warm water(25℃) were better in order. However, the extracts using EtOH-water, hot water or warm water included lots of caffeine and tannin which had bitter and astringent tastes, respectively. On the other hand, glycerin-water extracts was 10 times in yield as high as the previous solvent-extracts and had relatively low contents of caffeine and tannin. From these results, it can be concluded that glycerine-water is the most suitable solvent and its extracts can be most favorably used in the products of confectionary, gum, candy, etc.
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권오상,김용택 한국농업경제학회 2000 農業經濟硏究 Vol.41 No.2
An aggregate cost function has been estimated to decompose the productivity change in Korean agriculture between 1971 and 1998 to scale and technical change effects. The scale effect was the dominating source of productivity change until the late 1980s. Since Korean agricultural technology still exhibits an increasing returns to scale, the large amount of investment subsidy of the 1990s has contributed to productivity growth. However, the scale effect has been diminished sharply during the recent years, and the future productivity growth has to depend mainly on technological development.
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