• Title/Summary/Keyword: Catalyst, ZSM-5

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Effect of Change of Hydrogen Rich Reductant on HC-SCR over Co-Pt/ZSM5 Catalyst (수소 풍부 환원제 변화가 Co-Pt/ZSM5 촉매를 사용하는 탈질 HC-SCR 반응에 미치는 영향)

  • Kim, Seong-Soo;Kim, Dae-Young;Oh, Se-Young;Yoo, Seong-Jeon;Sur, Young-Sek;Kim, Jin-Gul
    • Journal of Hydrogen and New Energy
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    • v.23 no.3
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    • pp.199-206
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    • 2012
  • HC-SCR was conducted over Co-Pt/ZSM5 catalyst coated over 200 cpsi cordierite in the condition of atomspheric pressure and $200^{\circ}C-500^{\circ}C$. Weight ratio of Co/Pt determined from EDX analysis was 8/2, which was almost equal to the weight ratio at preparation step. XPS showed that nitrates within cobalt precursor and chlorine withn Pt precursor were removed. TEM result demonstrated that crystallite size of cobalt and Pt was under 5nm. Among these tested hydrocarbon reductants, isobutane ($i-C_4H_{10}$) showed the highest de-$NO_x$ yield of 80% under the condition of the mole ratio of reductant/NOx=1.0 at $180^{\circ}C$. De-$NO_x$ yield from HC-SCR was increased as the carbon number of hydrocarbon reductant was increased. The decrease of bonding energy between C and H of HC reductant played a role to increase of de-$NO_x$ yield, which indicated that the dissociation step of C-H bond of hydrocarbon molecule might be the rate determining step of HC-SCR. The increase of oxygen concentration in the feed resulted in the decrease of de-$NO_x$ yield but the increase of CO and $N_2O$ yield.

Effect of Change of Hydrocarbon Reductant on HC-SCR over Fe/ZSM5 Catalyst (탄화수소 환원제 변화가 Fe/ZSM5 촉매를 사용하는 탈질 HC-SCR 반응에 미치는 영향)

  • Kim, Seong-Soo;Kim, Dae-Young;Oh, Se-Yong;Yoo, Seong-Jeon;Park, Jeong-Hwan;Kim, Jin-Gul
    • Journal of Hydrogen and New Energy
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    • v.22 no.2
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    • pp.265-273
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    • 2011
  • HC-SCR was conducted using Fe/ZSM5 catalyst coated over 200 cpi cordierite in the conditions of atomspheric pressure and $200^{\circ}C-500^{\circ}C$. Among the tested hydrocarbon reductants, isobutane (i-$C_4H_{10}$) showed the highest de-$NO_x$ yield of 69% at $320^{\circ}C$ with the mole ratio of reductant/$NO_x$ =1.0. De-$NO_x$ yield resulted by the change of alkane reductant was increased as the carbon number of alkane reductant was increased. The order of increase of de-$NO_x$ yield was proportional to the order of decrease of bonding energy between C and H of reductant, where the H abstraction step from alkane molecule could be the rate controlling step of HC-SCR.

The Crystallization of ZSM-5 at Low Temperature and Atmospheric Pressure (저온 상압하에서 ZSM-5의 결정화 반응)

  • Kim, Wha Jung;Lee, Myung Churl;Kim, Jo Woong;Ha, Jae Mok
    • Applied Chemistry for Engineering
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    • v.8 no.2
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    • pp.320-331
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    • 1997
  • ZSM-5 was crystallized at low temperature and atmospheric pressure using reflux unit. The overall molar composition used in this study was $7.83Na_2O-0.25Al_2O_3-100SiO_2-xTPABr-yH_2O$ where x is 1 and 3 mol, and y is 3000 mol, 3500 mol, and 4000 mol. $2^3$ factorial experiments were performed with the results of kinetics studies, showing $Na_2O$, TPABr, and $H_2O$ as main factors. The result suggested that the concentration of $H_2O$ is the most important. The morphology of final product was very uniform showing well-defined crystals with BET surface area of ca. $410m^2/g$.

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Catalytic decomposition of HDPE over Al-MCM-48 using TGA and Py-GC/FID (TGA와 Py-GC/FID를 이용한 Al-MCM-48상에서 HDPE의 촉매(觸媒) 열분해(熱分解))

  • Kim, Young-Min;Kim, Seung-Do;Park, Young-Kwon;Kim, Ji-Man;Jeon, Jong-Ki
    • Resources Recycling
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    • v.15 no.5 s.73
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    • pp.17-25
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    • 2006
  • Al-MCM-48 was used as a catalyst to decompose high density polyethylene(HDPE). Catalytic activity of Al-MCM-48 was compared with those of Al-MCM-41, Beta, and ZSM-5. Catalytic decomposition rate over Al-MCM-48 was much higher than at of non-catalytic pyrolysis only. Compared to other catalysts, Al-MCM-48 revealed the little higher activation energy value. The progressive deactivation behavior of the catalysts has also studied. ZSM-5 and Al-MCM-48 showed slower deactivation rates than Al-MCM-41 and Beta. Pyrolysis coupled with gas chromatographic separation and flame ionization detection (Py-GC/ FID) was also performed to assess the characteristics of pyrolysis products. ZSM-5 gave a higher fraction of gaseous products ($C_1-C_4$). Al-MCM-41 and Beta produced mainly $C_5-C_{12}$ products. The selectivity to oil product ($C_5-C_{22}$) obtained with Al- MCM-48 is higher an that with the other catalysts employed in this study.

Dimethyl Ether Formation Using a Zeolite Catalyst Impregnated with Ceria (세리아 첨가 제오라이트 촉매를 이용한 디메틸 에테르 합성)

  • Kim, Bo-Kyung;Koh, Jae-Cheon;Kim, Beom-Sik;Han, Myung-Wan
    • Korean Chemical Engineering Research
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    • v.49 no.2
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    • pp.155-160
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    • 2011
  • Dimethyl ether draws an attention as a green fuel in recent years. In this study, we investigated dehydration of methanol to produce DME using solid-acid catalysts, a series of zeolite. We found that ceria took a role of promoting the reaction conversion as well as selectivity of DME formation as a cocatalyst to the zeolite catalyst. We varied Si/Al ratio and ceria percentage on the surface of the catalyst to get high performance catalyst. ZSM5-30 with 5 wt% ceria on the surface was found to have excellent DME selectivity and to be little influenced by water content in methanol feed. We proposed a reaction model and obtained kinetic parameters for the DME formation using the catalyst based on experimental results using a microreactor.

A Study on the Optimization of Ni-ZSM-5 Endothermic Catalyst Preparation for Decomposition of n-Dodecane (n-dodecane 분해를 위한 Ni-ZSM-5 흡열촉매 제조 최적화 연구)

  • Hyeonsu Jeong;Younghee Jang;Ye Hwan Lee;Sung Chul Kim;Byung Hun Jeong;Sung Su Kim
    • Applied Chemistry for Engineering
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    • v.34 no.6
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    • pp.619-625
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    • 2023
  • In order to solve problems caused by the heat load of hypersonic aircraft, this study examined the optimization of the Si/Al ratio of the catalyst and nickel ion exchange to improve the performance of the hydrocarbon decomposition reaction (endothermic reaction). It was confirmed that the catalysts prepared through Si/Al ratio optimization and nickel ion exchange showed about 10% improvement in heat absorption performance compared to thermal cracking at 4 MPa and 550 ℃. FT-IR and NH3-TPD analyses were found to identify factors affecting activity changes, and it was observed that the Si/Al ratio of the HZSM-5 catalyst was closely correlated with acid site development and catalytic activity. In addition, TGA and O2-TPO analyses were conducted to observe the carbon deposition inhibition properties of the nickel-added catalyst.

A Study of Upgrading Wax Oil Obtained from Pyrolysis of Mixed Plastic Waste with Film Type - The Influence of Catalyst Amount and Reaction Temperature (필름형 혼합폐플라스틱의 열분해로부터 얻은 왁스오일의 고급화연구 - 촉매 양과 반응온도의 영향 -)

  • Lee, Kyong-Hwan;Song, Kwang-Sup;Nam, Ki-Yun
    • New & Renewable Energy
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    • v.5 no.4
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    • pp.52-58
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    • 2009
  • Upgrading of pyrolysis wax oil using HZSM-5 catalyst has been conducted in a continuous fixed bed reactor at $450^{\circ}C$, 1hour, LHSV 3.5/h. The catalytic degradation was studied with a function of catalyst amount and reaction temperature. The raw pyrolysis wax oil shows relatively high boiling point distribution ranging from around $300^{\circ}C$ to $550^{\circ}C$, which has considerably higher boiling point distribution than that of commercial diesel. The catalytic degradation using HZSM-5 catalyst shows the high conversion of pyrolysis wax oil to light hydrocarbons. The liquid product obtained shows high gasoline range fraction as around 90% fraction and considerably high aromatic fraction in liquid product. Here, the experimental variable such as catalyst amount and reaction temperature was influenced on the product distribution.

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Shape-Selective Catalytic Reactions of Toluene with n-Propylalcohol Over ZSM-5 Zeolites (ZSM-5 제올라이트에서 n-프로필알코올의 톨루엔에 대한 형상 선택적 촉매반응)

  • Han-Yun Lee;Byoung Joon Ahn
    • Journal of the Korean Chemical Society
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    • v.37 no.3
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    • pp.317-326
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    • 1993
  • The acid catalytic reactions of toluene with n-propylalcohol were investigated and the adsorption experiments of dialkylbenzene isomers were carried out at 100$^{\circ}C$ over modified HZSM-5 zeolites. ZSM-5 zeolite was synthesized by the hydrothermal reaction using 4-propylammonium ion, sodium aluminate and colloidal silica etc., and several zeolite catalysts, including H-, K-, Sr-, P-Mg-HZSM-5, H-Y and H-mordenite, were prepared by conventional methods. The main reaction products of toluene with n-propylalcohol over HZSM-5 catalyst include not only xylenes, propyltoluenes, but also ethyltoluenes and high para-selectivity among dialkylbenzene isomers was observed on P-Mg-HZSM-5 zeolite. The diffusion coefficients of various p-dialkylbenzenes are nearly the same, about 1 ${times}$ 10$^{-10}$ cm$^2$/sec and that of m-xylene was about one tenth of o-xylene. These reaction and adsorption characteristics were interpreted in the light of the shape-selectivity related to related to the zeolite pore structure and the zeolitic acidity.

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The Effect of Promoter on the SO2-resistance of Fe/zeolite Catalysts for Selective Catalytic Reduction of NO with Ammonia (NO의 암모니아 선택적 촉매환원반응을 위한 철 제올라이트 촉매의 내황성에 미치는 조촉매 효과)

  • Ha, Ho-Jung;Choi, Joon-Hwan;Han, Jong-Dae
    • Clean Technology
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    • v.21 no.3
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    • pp.153-163
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    • 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 ℃.

Effect of Metal Addition and Silica/Alumina Ratio of Zeolite on the Ethanol-to-Aromatics by Using Metal Supported ZSM-5 Catalyst (금속담지 ZSM-5 촉매를 사용한 에탄올로부터 방향족 화합물 제조에 관한 제올라이트의 금속성분 및 실리카/알루미나 비의 영향)

  • Kim, Han-Gyu;Yang, Yoon-Cheol;Jeong, Kwang-Eun;Kim, Tae-Wan;Jeong, Soon-Yong;Kim, Chul-Ung;Jhung, Sung Hwa;Lee, Kwan-Young
    • Korean Chemical Engineering Research
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    • v.51 no.4
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    • pp.418-425
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    • 2013
  • The catalytic conversion of ethanol to aromatic compounds ETA was studied over ZSM-5 heterogeneous catalysts. The effect of reaction temperature, weight hourly space velocity (WHSV), and addition of water and methanol, which are the potential impurities of bio-ethanol, on the catalytic performance was investigated in a fixed bed reactor. Commercial ZSM-5 catalysts having different Si/$Al_2$ ratios of 23 to 280 and modified ZSM-5 catalysts by addition of metal (Zn, La, Cu, and Ga) were used for the activity and stability tests in ETA reaction. The catalysts were characterized with ammonia temperature programmed desorption ($NH_3$-TPD) and nitrogen adsorption-desorption techniques. The results of catalytic performance revealed that the optimal Si/$Al_2$ ratio of ZSM-5 is about 50~80 and the selectivity to aromatic compounds decreases in the order of Zn/La > Zn > La > Cu > Ga for the modified ZSM-5 catalysts. Among these catalysts from the ETA reaction, Zn-La/ZSM-5 showed the best catalytic performance for the ETA reaction. The selectivity to aromatic compounds was 72% initially and 56% after 30 h over the catalysts at reaction temperature of $437^{\circ}C$ and WHSV of $0.8h^{-1}$.