유동층에서 밀도가 다른 이성분 입자계의 flotsam 의 유출

장현태,차왕석,도동섭 ( Hyun Tae Jang,Wang Seog Cha,Dong Sup Doh ) 한국화학공학회 1996 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.34 No.1

The elutriation characteristics of flotsam for the size distribution of jetsam were investigated in continuous binary system with different density in a fluidized bed. In a fluidized bed of sand and PMMA(poly methyl metacrylate), sand was used as jetsam and PMMA as flotsam. Elutriation rate of flotsam, size distribution of elutriated particles and pressure fluctuations were measured for the size distribution of jetsam and elutriation rate of flotsam depended largely on the size distribution of jetsam. Using these results, it was found that elutriation of fine particles was partially reduced by controlling site distribution of jetsam. Fluidization characteristics were greatly influenced by the size distribution of jetsam and flotsam and these characteristics could be interpreted with standard deviation of pressure fluctuations.

압력요동을 이용한 밀도가 다른 이성분 혼합입자계의 최소유동화속도 측정

장현태,홍성창,도동섭 ( Hyun Tae Jang,Sung Chang Hong,Dong Sup Doh ) 한국화학공학회 1995 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.33 No.3

The determination method of minimum fluidization velocity from the linear regression of standard deviation of pressure fluctuation according to air velocity was investigated with binary mixture of sand and PMMA in a 0.109 m I.D. fluidized bed. The experiments were performed with change of operating variables such as the fraction of flotsam and particle size, and the measured values of the minimum fluidization velocity were compared with those obtained by the other researchers. The air velocity for this method has limited from well mixed region to freely bubbling region in a fluidized bed. The optimal measuring height of pressure fluctuations seems to be at middle levels on the axis of a bed, where the solid is well mixed.

분체공학 유동충 재료 ( 무기 , 유기 , 고분자 ) : 압력요동특성치를 이용한 유동층연소로에서 다입자계 유 , 무연탄 혼합연소특성 해석

장현태(Hyun Tae Jang),박태성(Tae Sung Park),도동섭(Dong Sup Doh) 한국화학공학회 1999 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.37 No.6

The combustion characteristics of mixture of anthracite and bituminous coal were studied in a fluidized bed (0.155 m-I.D., 2.2 m-height). The pressure fluctuations were measured by a pressure transducer under the various operating conditions. The properties of the pressure fluctuations, such as the standard deviation of pressure fluctuations, static pressure, cross-correlation function, dominant frequency and the power spectral density function, were obtained from the statistical analysis. The pressure fluctuation properties, particle size distribution of ash and composition of flue gas were measured to interpret the combustion characteristics in a fluidized bed combustor of uniform or multi-sized particles of mixed anthracite and bituminous coal have been compared with the particle size distribution, anthracite mixing fraction. From this study, the combustion characteristics of mixed fuels in a fluidized bed combustor could be interpreted by using standard deviation of pressure fluctuation and power spectrum distribution.

분체공학 유동층 재료 ( 무기 , 유기 , 고분자 ) / 유동층연소로에서 압력요동특성치를 이용한 균일입자계 유 무연탄 혼합연소특성 해석

장현태(Hyun Tae Jang),홍성창(Sung Chang Hong),차왕석(Wang Seog Cha),도동섭(Dong Sup Doh) 한국화학공학회 1999 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.37 No.4

The characteristics of mixed-firing of an anthracite and a bituminous coal were studied in a fluidized bed combustor(0.155 m-I.D., 2.2 m-height). The used domestic anthracite coal has heating value of 2,010 ㎉/㎏ and the imported high-calorific bituminous coal has heating value of 6,520 ㎉/㎏. The physicochemical analysis and the pressure fluctuation properties were measured to interpret the combustion characteristics in a fluidized bed combustor of uniform particles of mixed anthracite and bituminous coal is a function of the particle size ratio and the anthracite mixing fraction. The combustion characteristics of mixed fuels in a fluidized bed combustor could be interpreted by using standard deviation of pressure fluctuations, mean pressure and power spectrum density function. The different burning region of fluidized bed combustor was measured by the pressure fluctuation properties.

회분식 반응기에서 TiO₂ 광촉매의 MEK 분해특성-금속담지영향

장현태(Jang, Hyun-Tae),차왕석(Cha, Wang-Seog) 한국산학기술학회 2015 한국산학기술학회논문지 Vol.16 No.2

광촉매반응에서 티타니아에 금속물질을 담지하면 광촉매표면이 변화되며 담지된 금속물질은 반응속도를 증가시킨 다. 회분식 광반응기를 이용하여 TiO₂ 광촉매에 대한 금속물질 담지와 담지된 촉매의 소성조건 영향을 조사하였다. 광분해 효율을 증진시키기 위해 TiO₂ 촉매에 여러 종류의 금속물질을 담지하였다. 모든 실험에서의 수분함량은 3wt%, 반응기 온도 는 40℃이었다. TiO₂에 팔라듐을 담지한 경우가 가장 우수하였으며, Pt와 W을 첨가한 경우도 양호하였다. Pd/TiO₂ 촉매에 백금 또는 텅스텐을 부가적으로 담지하여도 제거효율에서의 증가는 없었다. 적절한 소성조건을 얻기위해 소성온도와 소성시 간에 대하여 다양하게 실험을 수행하였으며, 실험결과 최적의 소성조건은 소성온도 400℃, 소성시간 1시간이었다 In photocatalytic reaction, the doping of metal matter can alter the titania surface properties. As such the metal matter can increase the rate of the reaction. The influence of metal doping and calcination condition of TiO₂ photocatalyst was investigated at the batch-type photoreactor. Several metal matters were doped to the TiO₂ catalyst to improve photodegradation efficiency. During the experiments, water content was 3wt%, and reactor temperature was 40℃. Palladium-doped TiO₂ was found to be the best, where as platinum or tungsten-added also showed good results. Additional doping of platinum or tungsten on Pd/TiO₂ had no increase on the removal efficiency. To obtain proper calcination condition, various experiments about calcination temperature and time were carried out. As a result, the optimum calcination condition was temperature of 400℃, time of 1 hour.

소성 및 산소농도 조건에 대한 Mn-Cu-TiO₂ 촉매의 탈질 특성

장현태(Jang, Hyun-Tae),차왕석(Cha, Wang-Seog) 한국산학기술학회 2015 한국산학기술학회논문지 Vol.16 No.1

본 Mn-Cu-TiO2Civil촉매를 이용하여 질소산화물을 제거하는 NH3-SCR 공정에서 소성조건 및 산소농도에 대한 영향을 연구하였다. 소성된 촉매시료를 사용하여 H2-TPR 시스템에서 반응온도에 따른 수소전환특성을 조사하였으며, 소성조건에 대한 비표면적변화도 측정하였다. 실험결과 적합한 소성온도는 약 300℃이며, 소성온도가 500℃이상일 경우 Mn, Cu 성분의 저온활성이 크게 감소함을 알 수 있었다. SCR반응에서 기상산소는 중요한 반응변수이며 반응에 적합한 농도는 약8vol%이었다. DeNOx catalysts composed of Mn, Cu and TiO₂ were prepared and tested for NH3-SCR. The performance of each catalyst was studied for the NOx removal efficiency while changing the calcination temperature, reaction time, and oxygen concentration. The hydrogen conversion efficiency of a calcined catalyst was measured at the H₂-TPR system. The change in the specific surface area of catalyst according to the calcination temperature was analyzed. As a result, the proper calcination temperature was approximately 300℃. If the calcination temperature is increased to 500℃, the NOx removal efficiency of Mn and Cu constituents is largely decreased at the low temperature range. Oxygen in flue gas is an important parameter in the SCR reaction and optimal oxygen concentration is approximately 8 vol.%.

공기정화기용 광촉매 필터의 성능-귀금속 담지 영향

장현태(Jang, Hyun-Tae),김정근(Kim, Jeong-Keun),차왕석(Cha, Wang-Seog) 한국산학기술학회 2006 한국산학기술학회논문지 Vol.7 No.6

기상 휘발성 유기화합물인 아세톤과 포름알데히드에 대한 분해반응을 TiO₂ 광촉매에 귀금속을 혼합 탐지하여 분해능을 연구하였다. 아세톤의 경우 TiO₂에 팔라디움 혼합담지에 의하여 분해 반응성이 개선되었으며, 일반적인 광촉매 반응에 있어서 수분의 첨가시 OH기의 형성에 따른 분해반응성의 증가를 실험한 결과 아세톤의 경우 수분의 흡착에 의하여 분해반응성이 감소하는 것으로 나타났다. 아세톤의 경우 45℃가 최적으로 나타났으며, 포름알데히드의 경우는 75℃가 최적으로 나타났다. 귀금속 담지에 의한 영향에서는 아세톤의 경우 Pd를 TiO₂의 중량비 1wt%를 첨가 한 경우 반응성의 향상을 보았으며, 포름알데히드의 경우 Pt가 반응성의 향상을 나타내었다. This work examined improving the activity of photocatalyts by novel metal doping for the degradation of volatile organic compounds, such as formaldehyde and acetone. The activity was determined with type of dopant novel metal and volatile organic compounds. The palladium-doped TiO₂ was found to be improved the decomposition of acetone. The photocatalytic degradation rate for acetone was increased with decreasing temperature to 45t ℃ The optmum temperature of photocatalytic degradation rate for formaldehyde was 75℃. The enhancement of reaction rate with novel metal were 1.0 wt.% of palladium for acetone, 1.0 wt.% of plaitnum for formaldehyde.

V₂O₅/TiO₂ 촉매시스템의 황산화물에 대한 비활성화 특성

장현태(Jang, Hyun-Tae),차왕석(Cha, Wang-Seog) 한국산학기술학회 2015 한국산학기술학회논문지 Vol.16 No.11

암모니아를 환원제로 사용하는 선택적 촉매 환원법에서 V₂O₅/TiO₂ 촉매를 사용하여 황산화물에 대한 비활성화 특성 을 연구하였다. 반응온도와 황산화물 농도를 변경시키면서 촉매의 활성변화를 측정하였다. 촉매의 활성은 황산화물의 농도와 반응시간이 증가할수록 감소하였다. 또한 황산화물에 대한 촉매의 활성감소 정도는 반응온도 250~300℃의 범위에서 반응온 도가 증가할수록 크게 감소하였다. BET, XRD, SEM, TPD분석을 통해 비활성화된 촉매의 물리화학적인 특성을 조사하였다. 분석결과, 비활성화현상은 황산화물이 존재하는 상태에서 미반응 암모니아, 수분 등이 반응하여 황산암모늄이 생성되기 때문 이다. 황산암모늄은 촉매의 기공을 막으며 활성물질에 침적된다. Deactivation characteristics of V₂O₅/TiO₂ catalysts were studied for selective catalytic reduction(SCR) of NOx with ammonia in the presence of SO₂. Performance of catalyst was investigated for deNOx activity while changing temperature, SO₂ concentration. The activity of catalyst was decreased with the increase of SO₂ concentration and reaction time. Also, degree of activity drop was largely decreased with the increase of reaction temperature in the range of 250∼300℃. Physicochemical properties of deactivated catalysts were characterized by BET, XRD, SEM, TPD analysis. According to the analysis results, deactivation phenomena occur due to the relatively high formation of ammonium sulfate salts, which created by unreacted ammonia and water in the presence of SO₂. It was revealed that ammonium sulfate cause the pore plogging of support and deposition of active matter.

Gaussian 분포의 입자군의 표준편차에 따른 최소유동화속도

장현태 ( Hyun Tae Jang ),박태성 ( Tae Sung Park ),차왕석 ( Wang Seog Cha ) 한국화학공학회 2008 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.46 No.3

금속물질로 개질된 광촉매를 이용한 톨루엔 광분해특성 연구

장현태(Jang, Hyun-Tae),차왕석(Cha, Wang-Seog) 한국산학기술학회 2014 한국산학기술학회논문지 Vol.15 No.11

광촉매 반응에서 TiO₂에 금속물질을 첨가하면 촉매표면이 변화되며, 이러한 금속물질은 광분해반응의 속도를 증가시 킨다. 본 연구에서는 TiO₂ 광촉매의 광분해능력을 향상시키기 위해 다양한 방법을 이용하여 개질하였으며, 개질된 광촉매의 광분해특성은 회분식 광반응기를 이용하여 조사하였다. 우수한 TiO₂ 광촉매용액을 얻기 위해 여러 종류의 분산제와 안정제 를 조사하였으며, 분산제로는 isoproply alcohol, 안정제로는 sodium silicate가 적합하였다. 톨루엔 분해반응을 향상시키기 위해 다양한 금속물질을 TiO₂ 광촉매에 첨가하여 광분해효율을 조사한 결과 Pd가 가장 우수하였으며, Cu와 W도 우수하였 다. Pd를 첨가한 경우 25%의 제거효율 향상이 있었다. 그러나 Fe의 경우 광촉매분해반응을 상당히 저해하는 것으로 나타났 다. Pd/TiO₂ 광촉매에 Cu 또는 W를 부가적으로 첨가하여도 촉매의 광분해효율에는 증가가 없었다. In photocatalysis, the addition of metal matter to TiO₂ can alter the surface properties. As such, the metal can increase the rate of the photodegradation reaction. In this study, a range of modified TiO₂ photocatalysts were prepared and tested to improve the activity of photodegradation at a batch-typed photoreactor. To obtain a good sol solution of the TiO₂ photocatalyst, several types of dispersion agents and stabilizers were investigated. The photocatalyst solutions were modified with isoproply alcohol as the dispersion agent and sodium silicate as the stabilizer. The effects of various metallic elements on enhancing the photocatalytic activity of TiO₂ on the degradation of toluene were examined. Palladium-added TiO₂ was found to be the best, whereas copper or tungsten-added also showed good results. In the case of palladium addition, the increase in removal efficiency was 25%. On the other hand, Fe-added TiO₂ showed a notable decrease in photocatalytic degradation. Additional doping of copper or tungsten on the Pd/TiO₂ had no positive effect on the photodegradation activity.