• Title/Summary/Keyword: Fixed Bed

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Gas Phase Oxidation of Toluene and Ethyl Acetate over Proton and Cobalt Exchanged ZSM-5 Nano Catalysts- Experimental Study and ANN Modeling

  • Hosseini, Seyed Ali;Niaei, Aligholi;Salari, Dariush;Jodaei, Azadeh
    • Bulletin of the Korean Chemical Society
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    • v.31 no.4
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    • pp.808-814
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    • 2010
  • Activities of nanostructure HZSM-5 and Co-ZSM-5 catalysts (with different Co-loading) for catalytic conversion of ethyl acetate and toluene were studied. The catalysts were prepared by wet impregnation method and were characterized by XRD, BET, SEM, TEM and ICP-AES techniques. Catalytic studies were carried out inside a U-shaped fixed bed reactor under atmospheric pressure and different temperatures. Toluene showed lower reactivity than ethyl acetate for conversion on Co-ZSM-5 catalysts. The effect of Co loading on conversion was prominent at temperatures below $400^{\circ}C$ and $450^{\circ}C$ for ethyl acetate and toluene respectively. In a binary mixture of organic compounds, toluene and ethyl acetate showed an inhibition and promotional behaviors respectively, in which the conversion of toluene was decreased at temperatures above $350^{\circ}C$. Inhibition effect of water vapor was negligible at temperatures above $400^{\circ}C$. An artificial neural networks model was developed to predict the conversion efficiency of ethyl acetate on Co-ZSM-5 catalysts based on experimental data. Predicted results showed a good agreement with experimental results. ANN modeling predicted the order of studied variable effects on ethyl acetate conversion, which was as follows: reaction temperature (50%) > ethyl acetate inlet concentration (25.085%) > content of Co loading (24.915%).

Effect of Acetate Promotor on the Pd-Au/SiO2-catalyzed Synthesis of Vinyl Acetate from the Reaction of Ethylene with Acetic Acid (Pd-Au/SiO2 촉매에 의한 에틸렌과 아세트산으로부터 비닐 아세트산염의 생성반응에 대한 아세트산염의 촉진 효과)

  • Atashi, Hossein;Motahari, Kazem;Tabrizi, Farshad Farshchi;Sarkari, Majid;Fazlollahi, Farhad
    • Journal of the Korean Chemical Society
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    • v.55 no.1
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    • pp.92-97
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    • 2011
  • The effect of Group I alkali acetate promoters on vinyl acetate (VA) synthesis was evaluated. Catalyst product selectivity and ethylene conversion are compared to the unpromoted catalyst in the fixed-bed reactor with oxidation reaction of ethylene and acetic acid in gaseous phase over Pd-Au/$SiO_2$ catalyst. It was found that: a) the promoters were stabilized on the catalyst surface, b) common effect for the alkali promoted Pd-Au catalysts increaseed in product selectivity and ethylene conversion compared to unpromoted catalyst (these effects increase from top to the bottom of Group I). These promoting effect is due to the common-ion effect of acetate, present in the reaction, resulting in an increase in the activity of the catalyst. In addition a complementary theory for the effect of Au in the structure of the catalyst is proposed the imposition of distribution of palladium particles through decreasing the particle's diameter.

Virtual Flight Test for Conceptual Lunar Lander Demonstrator (달 착륙선 개념설계형상 검증모델 가상비행시험)

  • Lee, Won-Beom;Rew, Dong-Young
    • Aerospace Engineering and Technology
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    • v.12 no.1
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    • pp.87-93
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    • 2013
  • The conceptual design lunar lander demonstrator has been developed to use as a test bed for advanced spacecraft technologies and to test a prototype planetary lander capable of vertical takeoff and landing. Size of the lunar lander demonstrator is the same as that of lunar lander conceptually designed, however, the weight of lunar lander demonstrator is designed in 1/6 scale in consideration of gravity difference between moon and earth. The thruster clustering and virtual flight test were performed in the demonstrator fixed on the ground. The demonstrator ground test has been conducted for two months in the test site for the solid motor combustion of the Goheung Flight Center. The purposes of ground test of demonstrator are to demonstrate and verify essential electronics, propulsion system, control algorithm, embedded software, structure and system operation technologies before developing the flight model lander. This paper is described about the virtual flight test including test configuration, test aims and test facilities

Optimization of KOGAS DME Process From Demonstration Long-Term Test (KOGAS DME 공정의 실증 시험을 통한 최적화 기술개발)

  • Chung, Jongtae;Cho, Wonjun;Baek, Youngsoon;Lee, Changha
    • Journal of Hydrogen and New Energy
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    • v.23 no.5
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    • pp.559-571
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    • 2012
  • Dimethyl ether (DME) is a new clean fuel as an environmentally-benign energy resource. DME can be manufactured from various energy sources including natural gas, coal, and biomass. In addition to its environmentally friendly properties, DME has similar characteristics to those of LPG. The aim of this article is to represent the development of new DME process with KOGAS's own technologies. KOGAS has investigated and developed new innovative DME synthesis process from synthesis gas in gaseous phase fixed bed reactor. DME has been traditionally produced by the dehydration of methanol which is produced from syngas, a product of natural gas reforming. This traditional process is thus called the two-step method of preparing DME. However, DME can also be manufactured directly from syngas (single-step). The single-step method needs only one reactor for the synthesis of DME, instead of two for the two-step process. It can also alleviate the thermodynamic limitations associated with the synthesis of methanol, by converting the produced methanol into DME, thereby potentially enhancing the overall conversion of syngas into DME. KOGAS had launched the 10 ton/day DME demonstration plant project in 2004 at Incheon KOGAS LNG terminal. In the mid of 2008, KOGAS had finished the construction of this plant and has successively finished the demonstration plant operation. And since 2008, we have established the basic design of commercial plant which can produce 3,000 ton/day DME.

Adsorption Characteristics of Multi-component VOCs Including Poorly Adsorbable Chemicals on Activated Carbonaceous Adsorbents (비흡착성 화합물을 포함하는 다성분 VOCs의 탄소흡착제 흡착특성)

  • Woo, Kwang Jae;Kim, Sang Do;Lee, Si Hyun
    • Korean Chemical Engineering Research
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    • v.45 no.3
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    • pp.277-285
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    • 2007
  • The adsorption characteristics of multi-component solvent vapors including poorly-adsorbable chemicals such as toluene-xylene-MEK and toluene-MEK-IPA on the activated carbonaceous adsorbents were investigated in a stainless steel fixed bed of 10.2 cm ID and 50 cm in height in order to identify those carbons for eliminating and recovering solvent vapors from industrial emission sources. The used activated carbonaceous adsorbents were pelletized commercial activated carbons and activated carbon fiber. Breakthrough curves and adsorption capacity at atmospheric pressures were obtained. It has been found that non-polar and larger molecules have been adsorbed better than polar and smaller molecules. In special, alcohols and ketones were poorly adsorbed caused by competitive adsorbability in multi-component mixture system. However, it could be overcome by profitable employment of organization of cooperative system which was composed of different porosity activated carbonaceous adsorbents appropriately.

Avulsion of the Tibial Attachment of the Posterior Cruciate Ligament in a 13-year-old child - A Case Report - (13세 소아에서 후방십자인대의 경골 부착 부위의 견열 골절 - 증례보고-)

  • Lee Kwang-Won;Lee Seung-Hun;Kim Ha-Yong;Kim Byung-Sung;Choy Won-Sik
    • Journal of Korean Orthopaedic Sports Medicine
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    • v.1 no.1
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    • pp.61-64
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    • 2002
  • The authors report one case of isolated avulsion fracture of the tibial attachment of the posterior cruciate ligament. A 13 years old boy was admitted for right knee pain and swelling after the soccer injury on his knee. Hemarthrosis and posterior instability were present. Simple roentgenographic examination showed an isolated avulsion fracture of the tibial attachment of the posterior cruciate ligament. Open approach through the popliteal fossa was used and bony fragment was fixed into its bed using pull-out sutures. Postoperatively, a long leg cast was applied for 4 weeks. The patient was followed for 6 months. He returned to his previous activity levels. There was no residual laxity. Isolated avulsion of the posterior cruciate ligament from the tibia before the epiphyseal fusion is very rare in children. We reported one case of our experience and its result.

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Development of Bioreactors for Hydrogen-Producing Immobilized Photosynthetic Bacteria(II) : Evaluation of Immobilized Bioreactor for Hydrogen Productivity and Mass Transfer Resistance (광합성 박테리아를 이용한 고성능 수소 생산 고정화 생물반응기의 개발(II) :고정층 반응기와 연속 교반탱크 반응기에서의 수소 생산성 및 물질전달 저항 비교)

  • 선용호;한정우
    • KSBB Journal
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    • v.8 no.3
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    • pp.256-265
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    • 1993
  • In this study, it was observed that hydrogen productivity varied with changes of input g1ucose concentration and dilution rate in FBR( Fixed Bed Reactor), and CSTR(Continuous Stirred Tank Reactor). We evaluated and compared reaction rate Parameters and internal external and overall mass transfer resistances of immobilized carrier in both reactors. Apparent $K_m$ decreased with increasing dilution rate in FBR but showed a constant value above $0.4h^{-1}$ of dilution rate in CSTR. The experimental results in FBR showed nearly analogous to those in CSTR, however, the performance of FBR resulted in lower hydrogen productivity and an external effectiveness factor but a higher internal effectiveness factor than in CSTR. The overall effectiveness factor obtained with various input 91ucose concentrations showed similar values in both reactors.

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Decomposition of Aromatic Organic Solvents with Catalytic Oxidation in SC-CO2 (초임계 이산화탄소내 촉매산화분해에 의한 방향족 유기용매의 분해특성)

  • Lee, Seung Bum;Hong, In Kwon
    • Applied Chemistry for Engineering
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    • v.9 no.5
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    • pp.624-628
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    • 1998
  • The aromatic organic solvents(BTX) were decomposed in the fixed bed reactor packed with a 0.5% $Pt/{\gamma}-Al_2O_3$ catalyst, then, supercritical carbon dioxide(SC-$CO_2$) was used as the reaction media. And the conversion was dependent on the inlet concentration of BTX and the molar density of SC-$CO_2$. The conversion of BTX was decreased with increasing of inlet concentration, and was increased with temperature and pressure. The maximum conversion of benzene was 98.5% at $300^{\circ}C$ and 204.1 atm, and that of toluene and xylene were 82.0 and 76.5%, respectively, at $350^{\circ}C$ and 204.1 atm. The intermediate products of partial oxidation were identified as benzaldehyde, phenol, benzenemethanol, and so on. The BTX can be effectively converted into harmless $CO_2$ and $H_2O$ at appropriate operating condition. Thus, the nontoxic recovery process was suggested as the removal method of BTX.

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Study on basic characteristics for utilization of bituminous pyrolysis by-products (인도네시아 역청 열분해 무기 부산물의 활용을 위한 기초 특성 연구)

  • Jang, Jung Hee;Han, Gi Bo;Park, Cheon-Kyu;Jeon, Cheol-Hwan;Kim, Jae-Kon
    • Journal of the Korean Applied Science and Technology
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    • v.34 no.4
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    • pp.892-898
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    • 2017
  • In this study, the basic properties of recoverable gaseous and solid materials were investigated from heavy oil contained in the resources. The basic characteristics of pyrolysis reaction for the conversion of bituminous oil to pyrolysis various temperature were investigated. The characteristics of gas and solid phase byproducts were also investigated with a laboratory scale fixed bed reactor according to various reaction temperature. As a result, it was confirmed that the oil yield was about 17% at $550^{\circ}C$ and $CH_4$, $CaCO_3$ and CaO could be recovered as by-products.

Aquatic Plant Restoration by Mattress/Filter System in Stagnant Stream Channel (정체수역에서의 Mattress/Filter에 의한 수생식물 복원)

  • Yeo Woon-Ki;Heo Chang-Hwan;Lee Seung-Yun;Jee Hong-Kee
    • Journal of Environmental Science International
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    • v.15 no.1
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    • pp.21-31
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    • 2006
  • Aquatic plants grow in water with photosynthesis and purify water quality as taking organic and inorganic matter in water. Polluted water in stagnant stream channel where nutritive salts load is great can be purified by activities of aquatic plants. Aquatic plants should be fixed to bed easily to plant and sustainable environment is needed. So in this study, Mattress/Filter system is suggested to plant aquatic plant in stagnant stream channel. In the result of study, coverage of Phragmites australis, Zizania latifolia and Typha angustifolia which planted in mattress was $78\%,\;62\%\;and\;82\%$ and numbers of species in each mattress system were 7, 11, 3. The evenness index of each mattress system was 0.86, 0.91 and 0.79 and diversity index of each mattress system was 1.67. 2.18 and 0.87. Removal rates of phosphorus at Phragmites australis, Zizania latifolia and Typha angustifolia which planted in mattress were $68.7\%,\;62.7\%,\;55.3\%$ and removal rates of nitrogen of them were $79.8\%,\;74.7\%,\;64.9\%$. The removal rate of nitrogen was greater than phosphorus at all system and both removal rates were greater at Phragmites australis than at Zirania latifolia and at Typha angustifolia the rate was the least. Removal rates of $PO_4^{-3},\;NH_4-N,\;NO_{3-}N$ at Phragmites australis were $57.4\%,\;52.8\%,\;47.8\%$ and at Zizania latifolia were $82.6\%,\;77.2\%,\;67.5\%$ and at Typha angustifolia were $80.6\%,\;73.7\%,\;64.3\%$. It seems that removal effect is great by the planted mattress system.