• Clean Technology
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• v.14 no.3
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• pp.176-183
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• 2008

The purpose of this study is to upgrade the catalysts for synthesizing mixed octenes using normal butene and the catalysts for synthesizing $C_9$-aldehyde through hydroformylation of mixed octenes with syngas. The in-line activation method with circulating activating solution was effective for activation of the $NiO/A1_{2}O_3$ catalyst. The reason for catalyst deactivation may be ascribed to physi-sorbed materials or oligomers which block pore entrance and then prevent active sites from participating a reaction. Continuous distillation apparatus was used for separating mixed octenes from dimerization products. When reflux ratio was above 3 : 1, mixed octene fraction of which purity was above 99.57% was obtained. In $C_9$-aldehyde synthesis through hydroformylation of mixed octenes, we investigated a performance of ligand which increased catalyst stability as well as activity of Co catalyst. The results indicated that TPPO, NMP, NDMA, and succinonitrile were suitable ligand for increasing initial activity and reducing loss of Co during catalyst recovery.

• Applied Chemistry for Engineering
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• v.7 no.5
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• pp.1006-1014
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• 1996

A series of catalysts, $NiO-ZrO_2/WO_3$, for ethylene dimerization were prepared by coprecipitation from a solution of nickel chloride - zirconium oxychloride mixture followed by dry impregnation with an aqueous solution of ammonium metatungstate and calcination in air. On the basis of the results obtained from x-ray diffraction and DSC, the addition of NiO and $WO_3$ to $ZrO_2$ shifted the transition of $ZrO_2$ from amorphous to a tetragonal phase toward higher temperatures due to the interaction between NiO(or $WO_3$) and $ZrO_2$. $NiO-ZrO_2$ without $WO_3$ was inactive for the ethylene dimerization, but $NiO-ZrO_2/WO_3$ was found to be very active even at room temperature. The high catalytic activity of $NiO-ZrO_2/WO_3$ was closely correlated with the increase of acid strength by the inductive effect of $WO_3$.

• Korean Chemical Engineering Research
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• v.57 no.5
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• pp.714-722
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• 2019

Catalysts were prepared by using incipient wetness impregnation method with 17 wt% Ni on a support ($SiO_2-Y_2O_3$, $Al_2O_3$, $SiO_2-ZrO_2$, $SiO_2$, $TiO_2$, MgO) and the catalytic activity in the reductive amination of ethanol with ammonia in the presence of hydrogen was compared and evaluated. The catalysts used before and after the reaction were characterized using X-ray diffraction, nitrogen adsorption, ethanol-temperature programmed desorption (EtOH-TPD), isopropanol-temperature programmed desorption (IPA-TPD), and hydrogen chemisorption etc. In the case of preparing $ZrO_2$ and $Y_2O_3$ supports, the small amount of Si dissolution from the Pyrex reactor surface provoked the formation of mixed oxides $SiO_2-ZrO_2$ and $SiO_2-Y_2O_3$. Among the catalysts used, $Ni/SiO_2-Y_2O_3$ catalyst showed the best activity, and this good activity was closely related to the highest nickel dispersion, and low desorption temperature in EtOH-TPD and IPA-TPD. The low catalytic activity on Ni/MgO catalysts showed low activity due to the formation of NiO-MgO solid-solutions. In the case of $Ni/TiO_2$, the reactivity was low due to the low nickel metal phase due to strong metal-support interaction. In the case of using a support as $SiO_2-Y_2O_3$, $Al_2O_3$, $SiO_2-ZrO_2$, and $SiO_2$, the selectivities of ethylamines and acetonitrile were not significantly different at similar ethanol conversion.

• 한국신재생에너지학회:학술대회논문집
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• 2005.06a
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• pp.256-259
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• 2005

본 연구에서는 기존 니켈 활성성분만의 알루미나담지 촉매에 비해 고온에서의 수소를 사용한 환원 전처리 과정을 거치지 않고도 높은 반응활성을 나타내며, 반응 중 탄소침적에 대한 촉매 저항성에서도 우수한 결과를 나타낸 루테늄-니켈 촉매에 대해보고 하고자 한다. 메탄 수증기 개질 반응을 통해, 루테늄을 최종적으로 담지한 알루미나 담지니켈계 촉매는 별도의 전처리과정 없이 $650^{\circ}C$에서부터 높은 반응성을 보였으며, 루테늄과 니켈을 동시에 담지한 경우보다 더 우수한 활성을 나타내었다. Ru의 담지량을 달리한 실험에서는$RU(0.5)/Ni(20)/Al_2O_3$ 촉매가 가장 높은 활성을 보였다. $H_2-TPR$ 분석 결과, $Ru(0.5)/Ni(20)/A1_2O_3$촉매의 경우 세 가지 환원 피크가 나타났으며, $Ni(20)/A1_2O_3$촉매와 비교해 볼 때, 저온(<$130^{\circ}C)$에서 환원가능한 $RUO_2$의 존재를 확인할 수 있었다. 담지된 RU은 분산도가 높아, XRD분석 결과에서 Ru이나 $RuO_2$의 특성 피크가 존재하지 않았다. 또한 $650^{\circ}C$에서 10시간 개질반응 후 얻어진 촉매에 대해 $O_2-TGA$를 분석한 결과, $Ni(20)/Al_2O_3$촉매는 $-7.2wt\%$ 정도의 큰 무게 감소를 보였으며, 이는 촉매 표면에 생성된 carbon tube에 의한 것임을 SEM 분석을 통해 알 수 있었다 이에 반해, $Ru(0.5)/Ni(20)/Al_2O_$ 촉매는 $O_2-TGA$시 $0.3wt\%$ 정도 무게 증가에 그쳤으며, SEM 분석상 carbon tube의 생성이 크게 억제되었음을 알 수 있었다.

• Journal of the Korean Society of Propulsion Engineers
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• v.25 no.3
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• pp.56-61
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• 2021

In this study, Al₂O₃ and H-ZSM-5 were coated on the inner wall of the stainless steel tube for the stable use of liquid hydrocarbon fuel and an endothermic catalyst used as coolant for hypersonic flying vehicles. Coke production is inevitable by the endothermic decomposition reaction of the liquid hydrocarbon fuel, and Fe, Ni metals induce the production of the filamentous coke by using a stainless steel tube reactor as a cooling channel. By coating the stainless steel with H-ZSM-5, Fe and Ni metals are prevented from being directly exposed to the liquid hydrocarbon fuel, and the formation of the filamentous coke is inhibited. In addition, Al₂O₃ is coated between the stainless steel and H-ZSM-5 to enhance adhesion bond strength.

• Journal of Korean Society for Atmospheric Environment
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• v.10 no.4
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• pp.281-288
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• 1994

The hydrodesulfurization (DBT) were Peformed over NiPtMo catalysts supported on HZSM-5, LaY and ${\gamma}$- $Al_2$O$_3$under high H$_2$ pressure. And the acidities of these catalysts were characterized by using TGA and DSC. The result showed that the order of the acid strength for prepared supports was HZSM -5＞LaY＞${\gamma}$- A1$_2$O$_3$. For the acid amount we obtained the same result for the acid strength The acid strength and the acid amount mainly depended on the kinds of supports whose acid site were strong or not The activity of the hydrodesulfurization decreased for catalysts which had strong acid sites. The origin of acid site was Bronsted in NH50 and NY catalysts And it was Lewis in NA catalyst The order of desorption activation energy for Pyridine was NH50＞NY>NA. And the result was the same for thiophene. The activity of the hydrodesulfurization decreased for catalysts which had strong acid sites. The conversion of DBT over NA catalyst was higher than NH and NY catalysts.

• Journal of Korean Society for Atmospheric Environment
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• v.22 no.4
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• pp.431-439
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• 2006

Catalytic oxidation of benzene, toluene and xylene (BTX) using regenerated metal oxide catalysts (ZnO-CuO, NiO, $Fe_2O_3$, ZnO, CrO) were investigated in a fixed bed flow reactor to evaluate their feasibility for the purpose of removing volatile organic compounds (VOCs). Four kinds of pre-treatment methods such as gas (air and hydrogen), acid aqueous solution, alkali aqueous solution and cleaning agent were used to find out the optimal regeneration conditions. The physico-chemical properties of the used and regenerated catalysts were characterized by BET and TPR (Temperature Programmed Reduction). The used catalysts showed high conversion ratio and the catalytic ability of toluene oxidation was in the order of ZnO-CuO>$Fe_2O_3$>NiO>ZnO>CrO. We found that the acid aqueous pre-treatment (0.1 N HNO$_3$) was the best way to enhance the catalytic activity of $Fe_2O_3$. In addition, air and hydrogen gas treatment were optimal for NiO and ZnO-CuO catalysts, respectively. Furthermore, the decomposition of BTX depends on the type of a catalyst and a gas molecule.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.230.2-230.2
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• 2010

천연가스 수증기 개질 반응에 사용되는 펠릿 촉매의 단점인 열 및 물질 전달 제한, 낮은 effectiveness factor, 압력강화와 channeling 등의 문제점을 해결 하고자 모노리스 형태의 금속 구조체 촉매를 본 연구에 적용 하였다. Fecralloy 재질의 금속 구조체에 Ni 촉매를 워시코팅 (wash coating) 하여 제조 하였으며, 이를 천연가스 수증기 개질 반응에 적용하여 수소를 생산하였다. 실험 조건으로는 S/C ratio를 3으로 고정하여 온도를 $600^{\circ}C{\sim}800^{\circ}C$로 변화 시켰으며, GHSV $3000{\sim}30000h^{-1}$에서 진행 되었다. 구조체 촉매 코팅에 사용된 Ni 촉매의 BET, TPR, H2-chemisorption, SEM, EDS의 특성분석을 수행 하였다. 온도별 테스트에서 모노리스 형태의 금속 구조체 촉매가 펠릿 형태의 촉매에 비해 우수한 열전달 효과로 인해 낮은 퍼니스 온도와 높은 반응 활성을 나타내었으며, GHSV 변화에 따른 성능평가 결과도 15wt% $Ni/MgAl_2O_4$펠릿 촉매와 비교하여 금속 구조체 촉매가 높은 활성을 보였다.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.21 no.6
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• pp.822-829
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• 1997

A catalytic burner was studied which can be used as a heater operated in medium temperature. Noble metal catalysts (Pd/NiO) were used, which were supported on alumina wash coated honeycomb. The maximum heat-resisting temperature of the catalyst is about 900.deg. C. Combustion efficiency of the catalytic burner reached more than 99.5 % at the excess air ratio above 1.25.NOx emissions were lower than 1.0 ppm at all operation conditions. The operation condition for a stable catalytic combustion was obtained. It was dependent on the catalyst thickness. The 30 mm thick catalyst showed the widest stable catalytic combustion region. Stable catalytic combustion region of 30 mm thick catalyst was the operation condition of excess air ratio 1.25 - 1.75 and heat flux 7 - 14 kcal/h center dot cm$^{2}$.

• Transactions of the Korean hydrogen and new energy society
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• v.30 no.3
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• pp.209-219
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• 2019

Methanol is a liquid fuel which could also be produced from renewable energy sources and has appreciably high energy density. In this work, we investigated the application of $Ce_{0.9}Gd_{0.1}O_{2-x}$ supported Cu and Ni catalysts for hydrogen production via methanol steam reforming. Catalysts were synthesized by solution combustion synthesis. The prepared catalysts with various active materials and Cu loading amounts were tested in a reactor at $200-300^{\circ}C$, 0-5 barg range and steam to methanol molar ratio was 1.5. The catalytic properties of Cu and Ni were compared, and the catalytic performance was shown to depend on the amounts of metal loading and operating conditions such as reaction temperature and pressure.