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

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Characteristics of NOx Reduction on NSR(NOx Storage and Reduction) Catalyst Supported by Ni, Ru-ZSM-5 Additives (Ni, Ru-ZSM-5를 첨가한 NSR 촉매의 NOx 정화 특성)

  • Choi, Byung-Chul;Lee, Choon-Hee;Jeong, Jong-Woo
    • Transactions of the Korean Society of Automotive Engineers
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    • v.15 no.5
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    • pp.105-111
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    • 2007
  • In this study, we investigated the conversion performance of de-NOx catalyst for lean-burn natural gas engine. As a de-NOx catalyst, NOx storage reduction catalyst was composed of Pt, Pd and Rh with washcoat including Ba and Ni, Ru-ZSM-5. Ni, Ru-ZSM-5, which was regarded as a NOx direct decomposition catalyst, was made up of ion exchanged ZSM-5 by 5wt.% Ni or Ru. The performance of de-NOx catalyst was evaluated by NOx storage capacity and catalytic reduction in air/fuel, $\lambda=1.6$. The catalytic reaction was also observed when the added fuel was supplied to fuel rich atmosphere by fuel spike period of 5 seconds. The NOx conversion of the catalysts with Ni-ZSM-5 or Ru-ZSM-5 was mainly caused by the effect of NOx adsorption of Ba rather than the catalytic reduction of Ni, Ru-ZSM-5. Ni, Ru-ZSM-5 catalysts can not use for the NSR catalyst because they have quick process in thermal deactivation.

Effect of Temperature on Propylene Aromatization over MFI Type Zeolites (Propylene Aromatization에 미치는 온도 및 촉매의 영향)

  • Park, Jin-U;Kim, Sang-Bum;Kwak, Yun-Cheol;Shin, Ki-Seok;Park, Hong-Soo;Hahm, Hyun-Sik
    • Journal of the Korean Applied Science and Technology
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    • v.19 no.2
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    • pp.123-130
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    • 2002
  • [Ga]-MFI and H-ZSM-5 catalysts were synthesized under atmospheric pressure and used in the propylene aromatization. The effect of temperature on the product distribution was also investigated. The catalytic activities of the prepared catalysts were compared with the commercialized H-ZSM-5 which was converted from $NH_{4}$-ZSM-5. In the propylene aromatization, product distribution does not depend on the ratio of Si/$Ga_{2}$ with [Ga]-MFI catalyst, but depend on the ratio of Si/$Al_{2}$ with H-ZSM-5 catalyst [Ga]-MFI catalyst shows better dehydrogenation and alkylation activities than H-ZSM-5 catalyst The addition of Ga to H-ZSM-5 catalyst increases the conversion of propylene, selectivity to aromatics, and alkylation. In the propylene aromatization, the selectivity to aromatics slightly increased with increasing temperature with [Ga]-MFI catalyst, while slightly decreased with increasing temperature with H-ZSM-5 catalyst.

Pyrolysis Characteristics of Waste Ship Lubricating Oil using Waste Catalyst in Isothermal Tubular Type Pyrolysis Reactor (등온 열분해 반응기에서 폐촉매를 이용한 선박용 폐윤활유의 열분해반응 특성 연구)

  • Kim, Seung-Soo
    • Applied Chemistry for Engineering
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    • v.18 no.5
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    • pp.511-515
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    • 2007
  • The yield of oil was rapidly increased at $440^{\circ}C$ compared to $400^{\circ}C$ and $420^{\circ}C$ when the isothermal pyrolysis of waste ship lubricating oil was carried out in tubular type reactor, and pyrolysis was almost finished within 30 min. The yield of gas was decreased depending on the reaction temperature in which that of solid was not much changed. Pyrolysis experiments of waste ship lubricating oil were carried out with used ZSM-5 produced from a petrochemical process. The yield of gas was highly increased in the case of used ZSM-5 and fresh ZSM-5 compared to the case without catalyst. The produced oil and gas were almost constant for fresh ZSM-5 and used ZSM-5 at the same reaction temperature. In the reaction temperature $400{\sim}440^{\circ}C$, the selectivity of $C_5-C_{11}$ was two times higher with fresh ZSM-5 and used ZSM-5 than the case without catalyst.

Synthesis of the Hydrocarbons from Methanol over ZSM-5 Zeolite Catalyst (ZSM-5 제올라이트 촉매상에서의 메탄올로부터 탄화수소 합성반응)

  • Sang Eon Park;Hak Ze Chon
    • Journal of the Korean Chemical Society
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    • v.25 no.2
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    • pp.97-102
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    • 1981
  • The conversion of methanol to hydrocarbons has been studied over synthetic ZSM-5 zeolite catalyst having high silica to alumina ratio. The conversion products were olefins, paraffins, cycloparaffins, and aromatics, and the catalyst showed especially high selectivity toward the formation of aromatics. The catalyst showed the shape-selectivity and the size of molecules in the product was limited approximately to the size of 1,3,5-trimethylbenzene. Hydrogen form(HZSM-5) was more active, indicating reactions following the dehydration of methanol seemed to be mainly catalyzed by acid sites. Comparison of the reaction characteristics and acid site distribution of the ZSM-5 catalyst with those of mordenite and faujasite type catalysts suggests that cross-linked pore channel structure and the strong acidity of the ZSM-5 catalyst are primarily responsible for the selective formation of aromatics over this catalyst.

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Microstructures and Repeated Usage-Properties of de-$NO_{x}$ Transition Metals/ZSM-5 Catalyst Made by Mechanical Alloying Method (기계적합금화법을 이용하여 제조된 $NO_{x}$ 제거용 천이금속/ZSM-5촉매의 미세구조 및 반복사용특성)

  • 조규봉;안인섭;남태현
    • Journal of Powder Materials
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    • v.5 no.4
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    • pp.273-278
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    • 1998
  • $De-NO_x$ transition metals(Cu, Co)/ZSM-5 catalyst was made by mechanical alloying method, and their microstructures and repeated usage-properties were investigated by scanning electron microscopy, transmission electron microscopy and X-ray diffraction. The conversions ability of NO in the catalyst was measured. A part of ZSM-5 in CO/ZSM-5 composite powders was amorphous and the amorphous phase became less stable with increasing Co content. Conversion ability of NO in 10Cu/ZSM-5 powders decreased from 89% to 12% and that in 10Co/ZSM-5 decreased from 22% to 17% by 7 times conversion tests.

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Effect of Copper on the Properties of ZSM-5 Catalyst Fabricated by Mechanical Alloying Method (기계적합금화법에 의해 제조된 ZSM-5촉매특성에 미치는 Cu의 영향)

  • 안인섭
    • Journal of Powder Materials
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    • v.3 no.3
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    • pp.153-158
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    • 1996
  • The exhaust gas from vehicle engines and industrial boilers contains considerable amount of harmful nitrogen monoxide(NO) which causes air pollusion and acid rain. To remove NO catalytic reduction processes using Cu ion exchanged ZSM-5 zeolite have been widely studied. In this study, an attempt was made to fabricate Cu/zeolite catalyst by using high energy ball mill. The catalytic performance of ball milled Cu/ZSM-5 zeolites is analyzed and optimum copper contents was determined. The processing variables were reaction temperature and copper contents. Complete removal of NO gas was obtained at the temperature of 553 K on 10wt.% CU/ZSM-5 mechanically alloyed composite powders. Mechanically alloyed CU/ZSM-5 catalyst showed homogeneous distribution of Cu in ZSM-5.

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Reaction Characteristics and Catalytic Stability for the Methanol Conversion over ZSM-5 Catalyst (ZSM-5 촉매상에서 메탄올의 전환반응, 반응특성과 안정성)

  • Sang Eon Park;Hak Ze Chon
    • Journal of the Korean Chemical Society
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    • v.25 no.3
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    • pp.172-176
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    • 1981
  • The formation of $C_2-C_{10}$ hydrocarbons from methanol over shape-selective ZSM-5 zeolite catalysts is studied. It seems that $C_2-C_5$ olefins formed from methanol via dimethylether are transformed further to higher hydrocarbons containing higher concentration of aromatics by the acid sites of ZSM-5. Unique cross linked channel structure and its hydrophobicity seems to be mainly responsible for its high activity of ZSM-5 catalyst for the conversion of methanol.

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CATALYTIC DEGRADATION OF WASTE HIGH-DENSITY POLYETHYLENE INTO LIQUID PRODUCT

  • Lee, Kyong-Hwan;Shin, Dae-Hyun;Suh, Jeong-Kwon
    • Environmental Engineering Research
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    • v.10 no.2
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    • pp.54-61
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    • 2005
  • Liquid-phase catalytic degradation of waste high-density polyethylene (HDPE) over ZSM-5 (powder type (PW)) and ZSM-5+binder (granule type (GR)) has been investigated with a stirred semi-batch operation at 400°C. Two ZSM-5 catalysts with a different crystal size were synthesized and also each ZSM-5 (25%) Catalyst was mixed with a same binder (kaolin: silica sol: alumina = 55%:10%:10%). The performance of prepared catalysts that has different physicochemical properties was discussed with the cumulative amount distribution, molecular weight distribution and also paraffin, olefin, naphthene and aromatic (PONA) distribution in liquid product. These liquid product quality and distributions were changed depending on the physicochemical properties of the catalyst. Moreover, the characteristic of ZSM-5 in the catalyst was strongly influenced on the activity and PONA distribution in liquid product.

Fabrication and Characterization of Titanate Nanotube Supported ZSM-5 Zeolite Composite Catalyst for Ethanol Dehydration to Ethylene

  • Wu, Liangpeng;Li, Xinjun;Yuan, Zhenhong;Chen, Yong
    • Bulletin of the Korean Chemical Society
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    • v.35 no.2
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    • pp.525-530
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    • 2014
  • Titanium dioxide nanotube supported ZSM-5 zeolite composite catalyst was fabricated by decorating ZSM-5 zeolite on the hydrothermally synthesized titanium dioxide via hydrothermal process and subsequent annealing. The catalyst was characterized by X-ray powder diffraction (XRD), Transmission electron microscopy (TEM) and Nitrogen adsorption-desorption (BET). The surface acidity of the catalyst was measured by means of Fourier transform infrared (FT-IR) spectrum of pyridine adsorption. And the catalytic activity for ethanol dehydration to ethylene was evaluated in a continuous flow fixed-bed reactor. Attributed to the increase of the effective surface acid sites caused by titanium dioxide nanotube as electron acceptor, titanium dioxide nanotube supported ZSM-5 zeolite composite catalyst exhibits strongly enhanced activity for ethanol dehydration to ethylene.

Selective Disproportionation of Toluene over Various Cation-exchanged ZSM-5 Catalysts (양이온 교환된 ZSM-5 촉매상에서 톨루엔의 선택적인 반응)

  • Jong Shin Yoo;Byoung Joon Ahn;Hakze Chon
    • Journal of the Korean Chemical Society
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    • v.27 no.2
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    • pp.127-132
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    • 1983
  • The catalytic activity of ZSM-5 catalyst for the disproportionation of toluene is dependent on the type of cation exchanged, the degree of ion-exchange and the reaction temperature. The activity increases in the order of alkaline-, alkali earth-, hydrogen, and rare-earth-exchanged ZSM-5 and decreases with increasing degree of cation exchange. Among the ion-exchanged ZSM-5 catalyst, only Cs-ZSM-5 shows predominant selectivity for p-xylene. The selectivity increases with increasing degree of $Cs^+$-exchange and decreasing reaction temperature. This phenomenon is interpreted in terms of shape selectivity arising from the partial blocking of channel intersections by large cesium ions.

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