• Clean Technology
• /
• v.19 no.3
• /
• pp.287-294
• /
• 2013

The $NH_3$-selective catalytic reduction (SCR) reaction of NO with excess of oxygen were systematically investigated over Cu-zeolite and Fe-zeolite catalysts. Cu-zeolite and Fe-zeolite catatysts to adapt the SCR technology for mobile diesel engines were prepared by liquid ion exchange and incipient wetness impregnation of $NH_4$-BEA and $NH_4$-ZSM-5 zeolites. The catalysts were characterized by BET, XRD, FE-TEM (field emission transmission electron microscopy) and SEM/EDS. The SCR examinations performed under stationary conditions showed that the Cu-exchanged BEA catalyst revealed pronounced performance at low temperatures of $200{\sim}250^{\circ}C$. With respect to the Fe-zeolite catalyst, the Cu-zeolite catalyst showed a higher activity in the SCR reaction at low temperatures below $250^{\circ}C$. BEA zeolite based catalyst exhibited good activity in comparison with ZSM-5 zeolite based catalyst at low temperatures below $250^{\circ}C$.

• 한국신재생에너지학회:학술대회논문집
• /
• 2008.05a
• /
• pp.263-265
• /
• 2008

자원 재활용 및 에너지 생산관점에서 폐유지로부터 환경친화적인 연료인 바이오디젤에 대한 연구가 활발히 진행되고 있다. 특히 폐유지내 함유된 유리지방산 및 수분에 의해 효율적인 에스테르화 반응이 어렵기 때문에 이를 전처리 단계에서 제거되어야 한다. 본 연구에서는 폐유지내 유리지방산을 효과적으로 제거하기 위하여 회분식 반응기에서 제올라이트 촉매의 종류에 의한 세공구조와 산성도 변화에 따른 유리지방산 전환반응에 미치는 영향을 조사해 보았다. 제올라이트 촉매의 유리지방산 전환율은 세공구조와 산성도에 따라 큰 차이를 나타내었다. 유리지방산 전환율은 FAU < MOR < MFI < BEA의 순으로 높았다. 제올라이트의 세공구조는 1차원적인 구조를 가질 경우 탄소침적이 일어나지만 3차원적인 세공구조를 가지는 경우 탄소침적에 의한 촉매의 활성저하가 감소된다. 또한 제올라이트의 산성도에 따른 특성으로는 유리지방산의 전환반응에는 중간정도의 산세기를 가진 촉매가 유리함을 확인하였다. 그러므로 폐유지로부터 유리지방산을 제거하기 위한 우수한 제올라이트 촉매로는 BEA 제올라이트 촉매임을 확인하였다.

• Korean Chemical Engineering Research
• /
• v.47 no.3
• /
• pp.303-309
• /
• 2009

The effects of zeolite type catalysts addition on the thermal decomposition of low density polyethylene(LDPE) and ethylene vinyl acetate(EVA) resin have been studied in a thermal analyzer(TGA, DSC) and a small batch reactor. The zeolite type catalysts tested were natural zeolite, FCC catalyst, used FCC catalyst, and catalyst A. As the results of TGA experiments, addition of antifogging-agent decreased the pyrolysis point to $250^{\circ}C$, but addition of longevity-agent and clay reduced the pyrolysis rate in EVA resin. Addition of the zeolite type catalysts in the LDPE resin increased the pyrolysis rate in the order of catalyst A > used FCC catalyst > natural zeolite > LDPE resin. Addition of the zeolite type catalysts in the EVA resin increased the pyrolysis rate in the order of used FCC catalyst > natural zeolite > catalyst A > EVA resin. In the DSC experiments for LDPE resin, addition of zeolite type catalysts decreased the melting point and the heat of pyrolysis reaction in the order of catalyst A > used FCC catalyst > natural zeolite> LDPE resin. In the batch system experiments, the mixing of natural zeolite enhanced the yield of liquid fuel oil.

• Clean Technology
• /
• v.22 no.3
• /
• pp.161-167
• /
• 2016

Catalytic combustion of benzene over various metal cation-exchanged zeolites has been investigated. Y(4.8)-type zeolite showed the highest activity among the used zeolites and Cu/Y(4.8) catalyst also showed the highest activity among metal cation/ Y(4.8) zeolites. The catalytic activity increased according to the amount of adsorbed oxygen acquired from O₂ TPD results. The catalytic activity also increased with an increase of Cu cation concentration on Cu/Y(4.8) catalysts. The conversion of benzene on the combustion reaction depended on not benzene concentration but the oxygen concentration. In addition, the introduction of water into reactants decreased the catalytic activity.

• 한국신재생에너지학회:학술대회논문집
• /
• 2009.11a
• /
• pp.521-523
• /
• 2009

본 연구에서는 식물성유지와 메탄올로부터 전이에스테르화 반응에 의해 바이오디젤 제조에 사용되는 비균질촉매로 사용하기 위하여 NaX 제올라이트 촉매에 염기도를 향상시키기 위하여 KOH를 담지하여 담지량에 따른 바이오디젤 제조특성을 조사해보았다. KOH 담지량을 10wt% - 70wt%로 달리하여 Incipient wetness 방법으로 담지한후 $500^{\circ}C$에서 소성하여 촉매를 제조하고, 제조된 KOH의 담지량이 다른 KOH/NaX 제올라이트 촉매는 SEM, XRD, BET등을 통해 촉매특성을 평가하였고, 생성된 지방산 메틸에스테르는 가스크로마토그래피로 순도를 측정하였다. NaX 제올라이트 촉매에 KOH 담지량이 높은 경우와 촉매량이 많은 경우 바이오디젤제조에 유리하였고, 특히 반응시간과 반응온도는 $120^{\circ}C$, 2시간동안 반응한 경우 가장 좋은 지방산 메틸에스테르의 수율을 얻을 수 있었다.

• Applied Chemistry for Engineering
• /
• v.23 no.6
• /
• pp.614-617
• /
• 2012

Ti-containing zeolite was synthesised and used in the epoxidation of di-cyclopentadiene (DCPD). Among various Ti-zeolite catalysts, Y contained Ti-zeolite showed the highest yield in the epoxidation of DCPD. The study was also investigated in terms of the Ti content in the catalysts, $H_2O_2$/substrate ratio, reaction temperature and applied time. The reaction conditions significantly influenced on both the catalytic activity and selectivity. In addition, Ti structure in the zeolite was analyzed using IR and UV-vis spectroscopy.

• Clean Technology
• /
• v.21 no.3
• /
• pp.153-163
• /
• 2015

The effects of H₂O and residue SO₂ in flue gases on the activity of the Fe/zeolite catalysts for low-temperature NH₃-SCR of NO were investigated. And the addition effect of Mn, Zr and Ce to Fe/zeolite for low-temperature NH₃-SCR of NO in the presence of H₂O and SO₂ was investigated. Fe/zeolite catalysts were prepared by liquid ion exchange and promoted Fe/zeolite catatysts were prepared by liquid ion exchange and doping of Mn, Zr and Ce by incipient wetness impregnation. Zeolite NH₄-BEA and NH₄-ZSM-5 were used to adapt the SCR technology for mobile diesel engines. The catalysts were characterized by BET, X-ray diffraction (XRD), SEM/EDS, TEM/EDS. The NO conversion at 200 ℃ over Fe/BEA decreased from 77% to 47% owing to the presence of 5% H₂O and 100 ppm SO₂ in the flue gas. The Mn promoted MnFe/BEA catalyst exhibited NO conversion higher than 53% at 200 ℃ and superior to that of Fe/BEA in the presence of H₂O and SO₂. The addition of Mn increased the Fe dispersion and prevented Fe aggregation. The promoting effect of Mn was higher than Zr and Ce. Fe/BEA catalyst exhibited good activity in comparison with Fe/ZSM-5 catalyst at low temperature below 250 ℃.

• Journal of Energy Engineering
• /
• v.8 no.2
• /
• pp.248-255
• /
• 1999

Catalytic cracking of pyrolysed waste lubricating oil over solid acid catalysts (HY zeolite, ${\beta}$-zeolite, HZSM-5) has been carried out in a micro-fixed bed system. The feed oil for catalytic activity tests has been prepared by thermal cracking of waste lubricating oil under the reaction conditions of 480$^{\circ}C$, 60 min. Optimum reaction conditions for the maximum light oil yields($\_$21/) were WHSV(weight hourly space velocity)=1 at 375$^{\circ}C$. The amounts of total and strong acid sites appeared to be the largest in ${\beta}$-zeolite as determined by NH$_3$, TPD. It is seen that the catalytic activity order, in terms of the light fuel oil ($\_$21/) production, were HY zeolite)${\beta}$-zeolite>HZSM-5. Also, coke formation followed the same order. The highest activity in HY zeolite may be attributed from the fact that it has supercages facilitating the easy diffusion of larger molecules and also the effectiveness of the acid sites for cracking within the pore. This fact could be confirmed by the coke formation characteristics.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2006.05a
• /
• pp.193-196
• /
• 2006

This paper presents the results of catalytic endo- to exo- isomerization of saturated poly cyclic compound. Several zeolites were tested and influences of, Si/Al ratio and Structures of the zeolites on the reaction were investigated. The results showed that Y zeolites were more active than other zeolites, because of its large pore size and relative strong acidity. In all Y zeolites with different Si/Al, Y-5.4 is best. In all the zeolites tested, Y calcined at $450^{\circ}C$ was favorable. Still now the aluminium chloride catalyst is more active than zeolites. However, considering of environmental problems, corrosion, and treatment can make the zeolite catalyst substitute the aluminium chloride catalyst.

• 한국신재생에너지학회:학술대회논문집
• /
• 2008.10a
• /
• pp.83-84
• /
• 2008

바이오 디젤은 석유기반 연료들을 대신할 수 있는 대체연료일 뿐만 아니라 재생가능자원으로부터 얻을 수 있다는 장점을 가지고 있다. 바이오 디젤은 동 식물성 유지를 이용해서 알코올과 촉매 존재하에서 제조되며, 주로 KOH, NaOH 등 균질촉매를 이용하여 제조하는데 이는 폐수 발생이 많고 공정 비용이 많이 든다는 단점이 있다. 따라서 최근에는 폐기물 발생이 없고 촉매의 제거가 편리한 비균질촉매의 개발이 이루어지고 있다. 본 연구에서는 NaX 제올라이트 촉매에 KOH를 담지시켜 염기도의 증가에 따라 바이오디젤의 제조특성에 미치는 촉매특성을 조사해 보았다. NaX 제올라이트 촉매에 KOH 담지량이 증가와 반응시간이 증가함에 따라 바이오디젤 생성량은 증가하였다.