Ni/γ-Al₂O₃ 촉매상에서 이산화탄소에 의한 프로판의 개질

김경훈,김종화,장성진,박대원,Kim, K. H.,Kim, J. H.,Chang, S. C.,Park, D. W. 한국공업화학회 1997 공업화학 Vol.8 No.3

Reforming of propane by carbon dioxide using NiO/${\gamma}$-$A1_2O_3$ was carried out in a pulse or continuous kid bed reactor. NiO/${\gamma}$-$Al_2O_3$ showed higher dissociation ability of $CO_2$ than NiO/${\gamma}$-$Al_2O_3$, and the former exhibited higher conversion of propane than the latter. The presence of oxygen in the reaction mixture of propane and $CO_2$ increased the conversion of propane and reduced the amount of carbon deposit on the catalyst surface. Mechanical mixture catalyst of NiO/${\gamma}$-$Al_2O_3$ and $Ga_2O_3$ showed higher stability to deactivation than NiO/${\gamma}$-$Al_2O_3$ itself. The synergistic effect between NiO/${\gamma}$-$Al_2O_3$ and $Al_2O_3$ was also observed in this study. 본 연구는 펄스 반응기 및 고정층 연속반응기를 사용하여 ${\gamma}$-알루미나에 담지된 니켈촉매상에서 이산화탄소에 의한 프로판의 개질반응 특성을 고찰한 것이다 Ni/${\gamma}$-$A1_2O_3$촉매가 NiO/${\gamma}$-$A1_2O_3$촉매보다 $CO_2$의 해리능력과 프로판의 개질 능력이 우수한 것으로 나타났다. 프로판과 $CO_2$의 혼합물에 산소를 추가한 결과 프로판의 전환율이 증가하였고 표면의 탄소침적도 감소함을 알 수 있었다. Ni/${\gamma}$-$A1_2O_3$와 $Ga_2O_3$의 기계적 혼합 촉매는 Ni/${\gamma}$-$A1_2O_3$자체보다 촉매의 활성이 오래 유지되었고 두 상의 협동에 의한 상승효과(synergistic effect)가 관찰되었다.

Ni / γ- Al2O3 촉매상에서 이산화탄소에 의한 프로판의 개질

김경훈,김종화,장성진,박대원 ( K . H . Kim,J . H . Kim,S . C . Chang,D . W . Park ) 한국공업화학회 1997 공업화학 Vol.8 No.3

본 연구는 펄스 반응기 및 고정층 연속반응기를 사용하여 γ-알루미나에 담지된 니켈촉매상에서 이산화탄소에 의한 프로판의 개질반응 특성을 고찰한 것이다. Ni/γ-Al₂O₃촉매가 NiO/γ-Al₂O₃촉매보다 CO₂의 해리능력과 프로판의 개질 능력이 우수한 것으로 나타났다. 프로판과 CO₂의 혼합물에 산소를 추가한 결과 프로판의 전환율이 증가하였고 표면의 탄소침적도 감소함을 알 수 있었다. Ni/γ-Al₂O₃와 Ga₂O₃의 기계적 혼합 촉매는 Ni/γ-Al₂O₃자체보다 촉매의 활성이 오래 유지되었고 두 상의 협동에 의한 상승효과(synergistic effect)가 관찰되었다. Reforming of propane by carbon dioxide using Ni/γ-Al₂O₃ was carried out in a pulse or continuous fixed bed reactor. Ni/γ -Al₂O₃ showed higher dissociation ability of CO₂ than NiO/γ -Al₂O₃, and the former exhibited higher conversion of propane than the latter. The presence of oxygen in the reaction mixture of pmpane and CO₂ increased the conversion of propane and reduced the amount of carbon deposit on the catalyst surface. Mechanical mixture catalyst of Ni/γ-Al₂O₃ and Ga₂O₃ showed higher stability to deactivation than Ni/γ-Al₂O₃ itself. The synergistic effect between Ni/γ-Al₂O₃ and Ga₂O₃ was also observed in this study.

Sol-Gel 법을 이용한 칼슘-알루미네이트계 전자화물 박막의 제조와 특성

김경훈,박주석,채재홍,서원선,소성민,김태관,김형순,이병하,Kim, K.H.,Park, J.S.,Chae, J.H.,Seo, W.S.,So, S.M.,Kim, T.K.,Kim, H.S.,Lee, B.H. 한국결정성장학회 2010 한국결정성장학회지 Vol.20 No.6

Sol-gel법을 적용하여 $12CaO{\cdot}7Al_2O_3$(C12A7) 전자화물 박막을 제조하기 위해 CaO-$Al_2O_3$ sol을 제조하여 dip 코팅법을 적용하여 quartz 기판에 박막을 형성하였으며 열처리를 통해 C12A7의 박막을 제조하였다. C12A7 상의 형성 $800^{\circ}C$에서 시작되었고 $1,200^{\circ}C$ 온도에서 1시간 열처리를 통해 치밀화된 박막을 제조할 수 있었다. 제조된 C12A7 박막은 부도체였지만 수소 환원 분위기 열처리를 통해 전기전도도를 나타내기 시작했으며 $1,200^{\circ}C$ 48시간 열처리 시 120 S/cm의 전기전도도를 나타내었다. The Calcium-aluminate electride thin films on the quartz substrates was coated by sol-gel process. The crystallization of the C12A7 thin film was observed at $800^{\circ}C$ and high density C12A7 thin film was achieved on heat treatment at $1,200^{\circ}C$ for 1 hour. The reduction heat treatment of C12A7 thin film could be converted from insulator to conductor and the electrical conductivity was 120 S/cm in the C12A7 thin film heat treated at $1,200^{\circ}C$ with $H_2$ gas for 48 hours.

공기를 함유한 프레온 증기의 수평관 외부에서의 막응축

김경훈,고형종,Kim, K.H.,Ko, H.J. 대한설비공학회 1995 설비공학 논문집 Vol.7 No.1

A theoretical model for film condensation of a vapor including a relatively lighter noncondensable gas on a horizontal tube has been formulated on the basis of the conservation laws and other fundamental physical principles. The model is applied to the prediction of the condensation heat transfer characteristics for the Freon vapor in the presence of air on a horizontal tube. Calculated results for the mean heat transfer coefficient, which is shown to depend strongly on the bulk concentration of air, are in good agreement with the available experimental results for a range of operating conditions. The distributions of physical quantities along the surface of tube are also calculated, such as the boundary layer thickness and local heat transfer coefficient. The present model is readily reduced to the Nusselt model as the bulk concentration of air decreases to zero. Therefore, the transition from the condensation of pure vapor to that of vapor-air mixture occurs continuously not abruptly.

방전 플라즈마 소결법을 이용한 CoSb₃계 열전재료의 전극 접합 및 특성

김경훈,박주석,안종필,Kim, K.H.,Park, J.S.,Ahn, J.P. 한국결정성장학회 2010 韓國結晶成長學會誌 Vol.20 No.1

중고온용 열전 소재로 우수한 특성을 나타내는 $CoSb_3$계 소재의 열전 소자 제조를 위해 방전플라즈마 소결법을 이용하여 소결 및 Cu-Mo 전극 소재와의 접합을 동시에 실시하였다. $CoSb_3$ 내부로의 Cu 확산을 방지하기 위해 Ti을 중간층으로 삽입하였으며 열팽창계수의 조절을 위해 Cu : Mo = 3 : 7 부피비 조성을 선택하였다. 삽입된 Ti과 $CoSb_3$는 $TiSb_2$ 이 차상을 형성하면서 접합이 진행되었지만 접합 온도 및 접합 시간의 증가에 따라 TiSb 및 TiCoSb 등의 상의 형성에 의해 접합 계면에서 균열이 발생되어 접합 특성을 악화시키는 것으로 밝혀졌다. $CoSb_3$-based skutterudite compounds are promising candidates as thermoelectric (TE) materials used in intermediate temperature region. In this study, sintering of $CoSb_3$ powder and joining of $CoSb_3$ to copper-molybdenum electrode have been simultaneously performed by spark plasma sintering technique. The Ti foil was used for preventing the diffusion of copper into $CoSb_3$ and the Cu : Mo = 3 : 7 Vol. ratio composition was selected by the consideration of thermal expansion coefficients. The insertion of Ti interlayer between Cu-Mo and $CoSb_3$ was effective to join $CoSb_3$ to Cu-Mo by forming an intermediate layer of $TiSb_2$ at the Ti-$CoSb_3$ boundary. However, the formation of TiSb and TiCoSb intermediate layers deteriorated the joining properties by the generation of cracks in the interface of intermediate layer/$CoSb_3$ and intermediate/intermediate layers.

급수가열기 충격판 설계변경에 따른 동체감육 완화에 관한 유동해석 연구

김경훈,황경모,진태은,Kim K. H.,Hwang K. M.,Jin T. E. 한국시뮬레이션학회 2005 한국시뮬레이션학회 논문지 Vol.14 No.2

Feedwater heaters of many nuclear power plants have recently experienced wall thinning damage, which will increase as operating time progresses. As it is judged that the wall thinning damages have generated due to local fluid behavior around the impingement baffle installed in downstream of the high pressure turbine extraction steam line to avoid colliding directly with the tubes, numerical analyses using PHOENICS code were performed for two models with original clogged impingement baffle and modified multi-hole impingement baffle. To identify the relation between wall thinning and fluid behavior, the local velocity components in x-, y-, and z-directions based on the numerical analysis for the model with the clogged impingement baffle were compared with the wall thickness data by ultrasonic test. From the comparison of the numerical analysis results and the wall thickness data, the local velocity component only in the y-direction, and not in the x- and z-direction, was analogous to the wall thinning configuration. From the result of the numerical analysis for the modified impingement baffle to mitigate the shell wall thinning, it was identified that the shell wall thinning may be controlled by the reduction of the local velocity in the y-direction.

터보냉동기의 마이크로 프로세서 콘트롤 판넬

김경훈,Kim K. H. 대한설비공학회 1993 설비저널 Vol.22 No.4

빙축열을 이용한 저온급기/급수 냉방 시스템

김경훈,이종원,Kim, K.H.,Lee, J.W. 대한설비공학회 1991 설비저널 Vol.20 No.2

This paper presents some design guidelines for using cold air/water distribution to cool commercial and industrial buildings. Cold air /water distribution systems provide primary air/water for space conditioning at nominal temperature between $3^{\circ}C$ and $10^{\circ}C$ ($4{\sim}5^{\circ}C$ might be recommendable for better selection). By using lower temperature primary air/water equipment could be downsized, means lower first costs, and often reduce annual energy costs up to 50% less than that of the conventional ($13^{\circ}C$) system. This concept takes full advantages of the $2{\sim}4^{\circ}C$ chilled water (brine) available with ice storate systems.

시뮬레이션 프로그램을 이용한 Water Coil 능력계산

김경훈,박세현,Kim, K.H.,Park, S.H. 대한설비공학회 1994 설비저널 Vol.23 No.3

촉매 및 반응공학 Poster 발표 : 아크롤레인 선택 산화반응에서 Mo - V - O 와 금속산화물의 상간협동

김경훈,나석은,박대원 ( K . H . Kim,S . E . Na,D . W . Park ) 한국화학공학회 1994 춘계학술발표회 Vol.- No.-