WorldWideScience

Sample records for monolithic catalyst reactor

  1. Monolitni katalizatori i reaktori: osnovne značajke, priprava i primjena (Monolith catalysts and reactors: preparation and applications

    Directory of Open Access Journals (Sweden)

    Tomašić, V.

    2004-12-01

    Full Text Available Monolithic (honeycomb catalysts are continuous unitary structures containing many narrow, parallel and usually straight channels (or passages. Catalytically active components are dispersed uniformly over the whole porous ceramic monolith structure (so-called incorporated monolithic catalysts or are in a layer of porous material that is deposited on the walls of channels in the monolith's structure (washcoated monolithic catalysts. The material of the main monolithic construction is not limited to ceramics but includes metals, as well. Monolithic catalysts are commonly used in gas phase catalytic processes, such as treatment of automotive exhaust gases, selective catalytic reduction of nitrogen oxides, catalytic removal of volatile organic compounds from industrial processes, etc. Monoliths continue to be the preferred support for environmental applications due to their high geometric surface area, different design options, low pressure drop, high temperature durability, mechanical strength, ease of orientation in a reactor and effectiveness as a support for a catalytic washcoat. As known, monolithic catalysts belong to the class of the structured catalysts and/or reactors (in some cases the distinction between "catalyst" and "reactor" has vanished. Structured catalysts can greatly intensify chemical processes, resulting in smaller, safer, cleaner and more energy efficient technologies. Monolith reactors can be considered as multifunctional reactors, in which chemical conversion is advantageously integrated with another unit operation, such as separation, heat exchange, a secondary reaction, etc. Finally, structured catalysts and/or reactors appear to be one of the most significant and promising developments in the field of heterogeneous catalysis and chemical engineering of the recent years. This paper gives a description of the background and perspectives for application and development of monolithic materials. Different methods and techniques

  2. High-throughput reactor system with individual temperature control for the investigation of monolith catalysts.

    Science.gov (United States)

    Dellamorte, Joseph C; Vijay, Rohit; Snively, Christopher M; Barteau, Mark A; Lauterbach, Jochen

    2007-07-01

    A high-throughput parallel reactor system has been designed and constructed to improve the reliability of results from large diameter catalysts such as monoliths. The system, which is expandable, consists of eight quartz reactors, 23.5 mm in diameter. The eight reactors were designed with separate K type thermocouples and radiant heaters, allowing for the independent measurement and control of each reactor temperature. This design gives steady state temperature distributions over the eight reactors within 0.5 degrees C of a common setpoint from 50 to 700 degrees C. Analysis of the effluent from these reactors is performed using rapid-scan Fourier transform infrared (FTIR) spectroscopic imaging. The integration of this technique to the reactor system allows a chemically specific, truly parallel analysis of the reactor effluents with a time resolution of approximately 8 s. The capabilities of this system were demonstrated via investigation of catalyst preparation conditions on the direct epoxidation of ethylene, i.e., on the ethylene conversion and the ethylene oxide selectivity. The ethylene, ethylene oxide, and carbon dioxide concentrations were calibrated based on spectra from FTIR imaging using univariate and multivariate chemometric techniques. The results from this analysis showed that the calcination conditions significantly affect the ethylene conversion, with a threefold increase in the conversion when the catalyst was calcined for 3 h versus 12 h at 400 degrees C.

  3. Bench-Scale Monolith Autothermal Reformer Catalyst Screening Evaluations in a Micro-Reactor With Jet-A Fuel

    Science.gov (United States)

    Tomsik, Thomas M.; Yen, Judy C.H.; Budge, John R.

    2006-01-01

    Solid oxide fuel cell systems used in the aerospace or commercial aviation environment require a compact, light-weight and highly durable catalytic fuel processor. The fuel processing method considered here is an autothermal reforming (ATR) step. The ATR converts Jet-A fuel by a reaction with steam and air forming hydrogen (H2) and carbon monoxide (CO) to be used for production of electrical power in the fuel cell. This paper addresses the first phase of an experimental catalyst screening study, looking at the relative effectiveness of several monolith catalyst types when operating with untreated Jet-A fuel. Six monolith catalyst materials were selected for preliminary evaluation and experimental bench-scale screening in a small 0.05 kWe micro-reactor test apparatus. These tests were conducted to assess relative catalyst performance under atmospheric pressure ATR conditions and processing Jet-A fuel at a steam-to-carbon ratio of 3.5, a value higher than anticipated to be run in an optimized system. The average reformer efficiencies for the six catalysts tested ranged from 75 to 83 percent at a constant gas-hourly space velocity of 12,000 hr 1. The corresponding hydrocarbon conversion efficiency varied from 86 to 95 percent during experiments run at reaction temperatures between 750 to 830 C. Based on the results of the short-duration 100 hr tests reported herein, two of the highest performing catalysts were selected for further evaluation in a follow-on 1000 hr life durability study in Phase II.

  4. Green biodiesel production: a review on feedstock, catalyst, monolithic reactor, and supercritical fluid technology

    Directory of Open Access Journals (Sweden)

    Rizo Edwin Gumba

    2016-09-01

    Full Text Available The advancement of alternative energy is primarily catalyzed by the negative environmental impacts and energy depletion caused by the excessive usage of fossil fuels. Biodiesel has emerged as a promising substitute to petrodiesel because it is biodegradable, less toxic, and reduces greenhouse gas emission. Apart from that, biodiesel can be used as blending component or direct replacements for diesel fuel in automotive engines. A diverse range of methods have been reported for the conversion of renewable feedstocks (vegetable oil or animal fat into biodiesel with transesterification being the most preferred method. Nevertheless, the cost of producing biodiesel is higher compared to fossil fuel, thus impeding its commercialization potentials. The limited source of reliable feedstock and the underdeveloped biodiesel production route have prevented the full-scale commercialization of biodiesel in many parts of the world. In a recent development, a new technology that incorporates monoliths as support matrices for enzyme immobilization in supercritical carbon dioxide (SC-CO2 for continuous biodiesel production has been proposed to solve the problem. The potential of SC-CO2 system to be applied in enzymatic reactors is not well documented and hence the purpose of this review is to highlight the previous studies conducted as well as the future direction of this technology.

  5. Monitoring catalysts at work in their final form: spectroscopic investigations on a monolithic catalyst

    DEFF Research Database (Denmark)

    Rasmussen, Søren B.; Bañares, Miguel A.; Bazin, Philippe;

    2012-01-01

    A monolithic vanadia–titania based catalyst has been subjected to studies with in situ FTIR spectroscopy coupled with mass spectrometry, during the SCR (Selective Catalytic Reduction) reaction. A device based on a transmission reactor cell for monolithic samples was constructed, dedicated to the ...... with other surface or bulk sensitive techniques, e.g. Raman and UV-vis spectroscopy.......A monolithic vanadia–titania based catalyst has been subjected to studies with in situ FTIR spectroscopy coupled with mass spectrometry, during the SCR (Selective Catalytic Reduction) reaction. A device based on a transmission reactor cell for monolithic samples was constructed, dedicated....... The observations reported here serve as a demonstration of the great potential for the application of operando spectroscopy on monolithic systems. This cross disciplinary approach aims to identify reaction pathways, active sites, intermediate- and spectator-species for catalytic reactions under truly industrial...

  6. Intensification of Deep Hydrodesulfurization Through a Two-stage Combination of Monolith and Trickle Bed Reactors

    Institute of Scientific and Technical Information of China (English)

    Min Xu; Hui Liu⁎; Shengfu Ji; Chengyue Li

    2014-01-01

    Deep hydrodesulfurization (HDS) is an important process to produce high quality liquid fuels with ultra-low sul-fur. Process intensification for deep HDS could be implemented by developing new active catalysts and/or new types of reactors. In this work, the kinetics of dibenzothiophene (DBT) hydrodesulfurization over Ni-P/SBA-15/cordierite catalyst was investigated at 340-380 °C and 3.0-5.0 MPa. The first-order reaction model with respect to both DBT and H2 was used to fit the kinetics data in a batch recycle operation system. It is found that both the activation energy and rate constant over the Ni-P monolithic catalyst under our operating conditions are close to those over conventionally used HDS catalysts. Comparative performance studies of two types of reactors, i.e., trickle bed reactor and monolithic reactor, were performed based on reactor modeling and simulation. The results indicate that the productivity of the monolithic reactor is 3 times higher than that of the trickle bed reactor on a catalyst weight basis since effective utilization of the catalyst is higher in the monolithic reactor, but the volumetric productivity of the monolithic reactor is lower for HDS of DBT. Based on simulation results, a two-reactor-in-series configuration for hydrodesulfurization is proposed, in which a monolithic reactor is followed by a tickled bed reactor so as to attain intensified performance of the system converting fuel oil of different sulfur-containing compounds. It is il ustrated that the two reactor scheme outperforms the trickle bed reactor both on reactor volume and catalyst mass bases while the content of sulfur is reduced from 200μg·g-1 to about 10μg·g-1.

  7. Carbon Fiber Composite Monoliths as Catalyst Supports

    Energy Technology Data Exchange (ETDEWEB)

    Contescu, Cristian I [ORNL; Gallego, Nidia C [ORNL; Pickel, Joseph M [ORNL; Blom, Douglas Allen [ORNL; Burchell, Timothy D [ORNL

    2006-01-01

    Carbon fiber composite monoliths are rigid bodies that can be activated to a large surface area, have tunable porosity, and proven performance in gas separation and storage. They are ideal as catalyst supports in applications where a rigid support, with open structure and easy fluid access is desired. We developed a procedure for depositing a dispersed nanoparticulate phase of molybdenum carbide (Mo2C) on carbon composite monoliths in the concentration range of 3 to 15 wt% Mo. The composition and morphology of this phase was characterized using X-ray diffraction and electron microscopy, and a mechanism was suggested for its formation. Molybdenum carbide is known for its catalytic properties that resemble those of platinum group metals, but at a lower cost. The materials obtained are expected to demonstrate catalytic activity in a series of hydrocarbon reactions involving hydrogen transfer. This project demonstrates the potential of carbon fiber composite monoliths as catalyst supports.

  8. Carbon Fiber Composite Monoliths for Catalyst Supports

    Energy Technology Data Exchange (ETDEWEB)

    Contescu, Cristian I [ORNL; Gallego, Nidia C [ORNL; Pickel, Joseph M [ORNL; Blom, Douglas Allen [ORNL; Burchell, Timothy D [ORNL

    2006-01-01

    Carbon fiber composite monoliths are rigid bodies that can be activated to a large surface area, have tunable porosity, and proven performance in gas separation and storage. They are ideal as catalyst supports in applications where a rigid support, with open structure and easy fluid access is desired. We developed a procedure for depositing a dispersed nanoparticulate phase of molybdenum carbide (Mo2C) on carbon composite monoliths in the concentration range of 3 to 15 wt% Mo. The composition and morphology of this phase was characterized using X-ray diffraction and electron microscopy, and a mechanism was suggested for its formation. Molybdenum carbide is known for its catalytic properties that resemble those of platinum group metals, but at a lower cost. The materials obtained are expected to demonstrate catalytic activity in a series of hydrocarbon reactions involving hydrogen transfer. This project demonstrates the potential of carbon fiber composite monoliths as catalyst supports.

  9. Characterization of CIM monoliths as enzyme reactors.

    Science.gov (United States)

    Vodopivec, Martina; Podgornik, Ales; Berovic, Marin; Strancar, Ales

    2003-09-25

    The immobilization of the enzymes citrate lyase, malate dehydrogenase, isocitrate dehydrogenase and lactate dehydrogenase to CIM monolithic supports was performed. The long-term stability, reproducibility, and linear response range of the immobilized enzyme reactors were investigated along with the determination of the kinetic behavior of the enzymes immobilized on the CIM monoliths. The Michaelis-Menten constant K(m) and the turnover number k(3) of the immobilized enzymes were found to be flow-unaffected. Furthermore, the K(m) values of the soluble and immobilized enzyme were found to be comparable. Both facts indicate the absence of a diffusional limitation in immobilized CIM enzyme reactors.

  10. Conversion of methanol to gasoline-range hydrocarbons in a ZSM-5 coated monolithic reactor

    Energy Technology Data Exchange (ETDEWEB)

    Antia, J.E.; Govind, R. (Univ. of Cincinnati, OH (United States). Dept. of Chemical Engineering)

    1995-01-01

    Novel reactor configurations featuring catalysts supported on monolithic or honeycomb structures are being increasingly used for a number of applications. In this work, a zeolite-coated monolithic reactor is employed for the conversion of methanol to gasoline-range hydrocarbons. Experimental results show that the conversion and hydrocarbon product distribution compare favorably with data reported for fixed and fluid beds. Mathematical modeling shows that the conversion here is controlled by diffusion in the molecule-sized intracrystalline pores of the zeolite structure. This finding is of considerable important because it demonstrates that monolithic reactors are well-suited to zeolite-based catalytic processes.

  11. Pybox monolithic miniflow reactors for continuous asymmetric cyclopropanation reaction under conventional and supercritical conditions.

    Science.gov (United States)

    Burguete, M I; Cornejo, A; García-Verdugo, E; Gil, María J; Luis, S V; Mayoral, J A; Martínez-Merino, V; Sokolova, M

    2007-06-08

    Supported catalysts having pybox chiral moieties were prepared as macroporous monolithic miniflow systems. These catalysts are based on styrene-divinylbenzene polymeric backbones having different compositions and pybox chiral moieties. Their corresponding ruthenium complexes were tested for the continuous flow cyclopropanation reaction between styrene and ethyldiazoacetate (EDA) under conventional conditions and in supercritical carbon dioxide (scCO2). Ru-Pybox monolithic miniflow reactors not only provided a highly efficient and robust heterogeneous chiral catalyst but also allowed us to develop more environmental reaction conditions without sacrificing the global efficiency of the process.

  12. Ni catalyst wash-coated on metal monolith with enhanced heat-transfer capability for steam reforming

    Science.gov (United States)

    Ryu, Jae-Hong; Lee, Kwan-Young; La, Howon; Kim, Hak-Joo; Yang, Jung-Il; Jung, Heon

    A commercial Ni-based catalyst is wash-coated on a monolith made of 50 μm-thick fecralloy plates. Compared with the same volume of coarsely powdered Ni catalysts, the monolith wash-coated Ni catalysts give higher methane conversion in the steam reforming reaction, especially at gas hourly space velocities (GHSV) higher than 28,000 h -1, and with no pressure drop. A higher conversion of the monolith catalyst is obtained, even though it contains a lower amount of active catalyst (3 g versus 17 g for a powdered catalyst), which indicates that the heat-transfer capability of the wash-coated Ni catalyst is significantly enhanced by the use of a metal monolith. The efficacy of the monolith catalyst is tested using a shell-and-tube type heat-exchanger reactor with 912 cm 3 of the monolith catalyst charged on to the tube side and hot combusted gas supplied to the shell side in a counter-current direction to the reactant flow. A methane conversion greater than 94% is obtained at a GHSV of 7300 h -1 and an average temperature of 640 °C. Nickel catalysts should first be reduced to become active for steam reforming. Doping a small amount (0.12 wt.%) of noble metal (Ru or Pt) in the commercial Ni catalyst renders the wash-coated catalyst as active as a pre-reduced Ni catalyst. Thus, noble metal-doped Ni appears useful for steam reforming without any pre-reduction procedure.

  13. Acidic Montmorillonite/Cordierite Monolithic Catalysts for Cleavage of Cumene Hydroperoxide

    Institute of Scientific and Technical Information of China (English)

    Li Han; Yanjun Wang; Jie Zhang; Zhigang Lei; Chongpin Huang; Biaohua Chen

    2014-01-01

    In this work, a series of acidic montmorillonite/cordierite monolithic catalysts were prepared by a coating method using silica sol as the binder. The morphology and structure of the acidic montmoril onite/cordierite samples were characterized by means of X-ray diffraction (XRD), N2 adsorption/desorption isotherms, and scanning electron microscope (SEM). The cleavage of cumene hydroperoxide (CHP) in a conventional fixed-bed reactor was chosen as a model reaction to evaluate the catalytic activity of the monolithic catalysts. The influences of acidic montmorillonite loading, reaction temperature, CHP concentration, and weight hourly space velocity (WHSV) on the catalytic activity and selectivity of phenol were studied. The results indicated that the obtained acidic montmorillonite/cordierite monolithic catalysts were firm and compact, and the loading of acidic montmorillonite was found to reach 40%(by mass) after three coating operations. The surface area of acidic montmorillonite/cordierite catalysts increases greatly as acidic montmorillonite loading increases due to higher surface area of acidic montmorillonite. Under the optimal reaction conditions (acidic montmorillonite loading of 32.5%(by mass), temperature of 80 °C, a mass ratio of CHP to acetone of 1:3, and WHSV of CHP of 90 h-1), the conversion of CHP can reach 100%, and the selectivity of phenol is up to 99.8%.

  14. Testing commercial catalysts in recycle reactors

    Energy Technology Data Exchange (ETDEWEB)

    Berty, J.M.

    1979-01-01

    Recycle reactors for quality control of catalyst production and for testing new catalysts for known or new processes have the following advantages over tubular reactors: they can reproduce the physical and chemical regime which surrounds the catalyst in a commercial reactor; they can achieve high mass and heat transfer; they exhibit uniform coke deposit; and they provide independence of mass velocity and space velocity. Their disadvantage is the unconventional specification of experiments in terms of discharge concentration which derives from the implicit nature of the basic mathematical relationships. Recycle reactor test methods are outlined for quality control and for testing catalysts, e.g., supported nickel from different manufacturers, for processes whose chemistry is well known. Approaches for testing catalysts for new processes are discussed. The standard recycle reactor developed at Union Carbide Corp. and manufactured by Autoclave Engineers, and several of its modifications are described.

  15. REACTOR FILLED WITH CATALYST MATERIAL, AND CATALYST THEREFOR

    NARCIS (Netherlands)

    Sie, S.T.

    1995-01-01

    Abstract of WO 9521691 (A1) Described is a reactor (1) at least partially filled with catalyst granules (11), which is intended for catalytically reacting at least one gas and at least one liquid with each other. According to the invention the catalyst granules (11) are collected in agglomerates

  16. Hydrocarbon reforming catalysts and new reactor designs for compact hydrogen generators

    Energy Technology Data Exchange (ETDEWEB)

    Schaefer, A.; Schwab, E.; Urtel, H. [BASF SE, Ludwigshafen (Germany); Farrauto, R. [BASF Catalysts LLC, Iselin, NJ (United States)

    2010-12-30

    A hydrogen based future energy scenario will use fuel cells for the conversion of chemically stored energy into electricity. Depending upon the type of fuel cell, different specifications will apply for the feedstock which is converted in the cell, ranging from very clean hydrogen for PEM-FC's to desulfurized methane for SOFC and MCFC technology. For the foreseeable future, hydrogen will be supplied by conventional reforming, however operated in compact and dynamic reformer designs. This requires that known catalyst formulations are offered in specific geometries, giving flexibility for novel reactor design options. These specific geometries can be special tablet shapes as well as monolith structures. Finally, also nonhydrocarbon feedstock might be used in special applications, e.g. bio-based methanol and ethanol. BASF offers catalysts for the full process chain starting from feedstock desulfurization via reforming, high temperature shift, low temperature shift to CO fine polishing either via selective oxidation or selective methanation. Depending upon the customer's design, most stages can be served either with precious metal based monolith solutions or base metal tablet solutions. For the former, we have taken the automobile catalyst monolith support and extended its application to the fuel cell hydrogen generation. Washcoats of precious metal supported catalysts can for example be deposited on ceramic monoliths and/or metal heat exchangers for efficient generation of hydrogen. Major advantages are high through puts due to more efficient heat transfer for catalysts on metal heat exchangers, lower pressure drop with greater catalyst mechanical and thermal stability compared to particulate catalysts. Base metal tablet catalysts on the other hand can have intrinsic cost advantages, larger fractions of the reactor can be filled with active mass, and if produced in unconventional shape, again novel reactor designs are made possible. Finally, if it comes to

  17. Development of the Monolith Froth Reactor for Catalytic Wet Oxidation of CELSS Model Wastes

    Science.gov (United States)

    Abraham, Martin; Fisher, John W.

    1995-01-01

    The aqueous phase oxidation of acetic acid, used as a model compound for the treatment of CELSS (Controlled Ecological Life Support System) waste, was carried out in the monolith froth reactor which utilizes two-phase flow in the monolith channels. The catalytic oxidation of acetic acid was carried out over a Pt/Al2O3 catalyst, prepared at The University of Tulsa, at temperatures and pressures below the critical point of water. The effect of externally controllable parameters (temperature, liquid flow rate, distributor plate orifice size, pitch, and catalyst distance from the distributor plate) on the rate of acetic acid oxidation was investigated. Results indicate reaction rate increased with increasing temperature and exhibited a maximum with respect to liquid flow rate. The apparent activation energy calculated from reaction rate data was 99.7 kJ/mol. This value is similar to values reported for the oxidation of acetic acid in other systems and is comparable to intrinsic values calculated for oxidation reactions. The kinetic data were modeled using simple power law kinetics. The effect of "froth" feed system characteristics was also investigated. Results indicate that the reaction rate exhibits a maximum with respect to distributor plate orifice size, pitch, and catalyst distance from the distributor plate. Fundamental results obtained were used to extrapolate where the complete removal of acetic acid would be obtained and for the design and operation of a full scale CELSS treatment system.

  18. Conversion of Hydrogen Sulfide in Coal Gases to Liquid Elemental Sulfur with Monolithic Catalysts

    Energy Technology Data Exchange (ETDEWEB)

    K. C. Kwon

    2006-09-30

    CO components of syngas appear to behave as inert with respect to sulfur formed at the SSRP conditions. One problem in the SSRP process that needs to be eliminated or minimized is COS formation that may occur due to reaction of CO with sulfur formed from the Claus reaction. The objectives of this research are to formulate monolithic catalysts for removal of H{sub 2}S from coal gases and minimum formation of COS with monolithic catalyst supports, {gamma}-alumina wash or carbon coats, and catalytic metals, to develop a catalytic regeneration method for a deactivated monolithic catalyst, to measure kinetics of both direct oxidation of H{sub 2}S to elemental sulfur with SO{sub 2} as an oxidizer and formation of COS in the presence of a simulated coal gas mixture containing H{sub 2}, CO, CO{sub 2}, and moisture, using a monolithic catalyst reactor, and to develop kinetic rate equations and model the direct oxidation process to assist in the design of large-scale plants. This heterogeneous catalytic reaction has gaseous reactants such as H{sub 2}S and SO{sub 2}. However, this heterogeneous catalytic reaction has heterogeneous products such as liquid elemental sulfur and steam. To achieve the above-mentioned objectives using a monolithic catalyst reactor, experiments on conversion of hydrogen sulfide into elemental sulfur and formation of COS were carried out for the space time range of 40-560 seconds at 120-150 C to evaluate effects of reaction temperatures, total pressure, space time, and catalyst regeneration on conversion of hydrogen sulfide into elemental sulfur and formation of COS. Simulated coal gas mixtures consist of 3,600-4,000-ppmv hydrogen sulfide, 1,800-2,000 ppmv sulfur dioxide, 23-27 v% hydrogen, 36-41 v% CO, 10-12 v% CO{sub 2}, 0-10 vol % moisture, and nitrogen as remainder. Volumetric feed rates of a simulated coal gas mixture to the reactor are 30-180 SCCM. The temperature of the reactor is controlled in an oven at 120-150 C. The pressure of the reactor

  19. Pt-based Bi-metallic Monolith Catalysts for Partial Upgrading of Microalgae Oil

    Energy Technology Data Exchange (ETDEWEB)

    Lawal, Adeniyi [Stevens Inst. of Technology, Hoboken, NJ (United States); Manganaro, James [Anasyn LLC, Princeton, NJ (United States); Goodall, Brian [Valicor Renewables LLC, Dexter, MI (United States); Farrauto, Robert [Columbia Univ., New York, NY (United States)

    2015-03-24

    Valicor’s proprietary wet extraction process in conjunction with thermochemical pre-treatment was performed on algal biomass from two different algae strains, Nannochloropsis Salina (N.S.) and Chlorella to produce algae oils. Polar lipids such as phospholipids were hydrolyzed, and metals and metalloids, known catalyst poisons, were separated into the aqueous phase, creating an attractive “pre-refined” oil for hydrodeoxygenation (HDO) upgrading by Stevens. Oil content and oil extraction efficiency of approximately 30 and 90% respectively were achieved. At Stevens, we formulated a Pt-based bi-metallic catalyst which was demonstrated to be effective in the hydro-treating of the algae oils to produce ‘green’ diesel. The bi-metallic catalyst was wash-coated on a monolith, and in conjunction with a high throughput high pressure (pilot plant) reactor system, was used in hydrotreating algae oils from N.S. and Chlorella. Mixtures of these algae oils and refinery light atmospheric gas oil (LAGO) supplied by our petroleum refiner partner, Marathon Petroleum Corporation, were co-processed in the pilot plant reactor system using the Pt-based bi-metallic monolith catalyst. A 26 wt% N.S. algae oil/74 wt % LAGO mixture hydrotreated in the reactor system was subjected to the ASTM D975 Diesel Fuel Specification Test and it met all the important requirements, including a cetane index of 50.5. An elemental oxygen analysis performed by an independent and reputable lab reported an oxygen content of trace to none found. The successful co-processing of a mixture of algae oil and LAGO will enable integration of algae oil as a refinery feedstock which is one of the goals of DOE-BETO. We have presented experimental data that show that our precious metal-based catalysts consume less hydrogen than the conventional hydrotreating catalyst NiMo Precious metal catalysts favor the hydrodecarbonylation/hydrodecarboxylation route of HDO over the dehydration route preferred by base metal

  20. Nanosized CuO and ZnO Catalyst Supported on Honeycomb-Typed Monolith for Hydrogenation of Carbon Dioxide to Methyl Alcohol.

    Science.gov (United States)

    Park, Chul-Min; Ahn, Won-Ju; Jo, Woong-Kyu; Song, Jin-Hun; Oh, Chang-Yeop; Jeong, Young-Shin; Chung, Min-Chul; Park, Kwon-Pil; Kim, Ki-Joong; Jeong, Woon-Jo; Sohn, Bo-Kyun; Jung, Sang-Chul; Lee, Do-Jin; Ahn, Byeong-Kwon; Ahn, Ho-Geun

    2015-01-01

    The greenhouse effect of carbon dioxide (CO2) has been recognized as one of the most serious problems in the world. Conversion of CO2 to methyl alcohol (CH3OH) was studied using catalytic chemical methods. Honeycomb-typed monolith used as catalyst support was 400 cell/inch2. Pretreatment of the monolith surface was carried out by thermal treatment and acid treatment. Monolith-supported nanosized CuO-ZnO catalysts were prepared by wash-coat method. The prepared catalysts were characterized by using SEM, TEM, and XRD. The catalytic activity for CO2 hydrogenation to CH3OH was investigated using a flow-type reactor with varying reaction temperature, reaction pressure and contact time. Conversion of CO2 was increased with increasing reaction temperature, but selectivity to CH3OH was decreased. Optimum reaction temperature was about 250 degrees C under 20 atm. Because of the reverse water gas shift reaction.

  1. Conversion of Hydrogen Sulfide in Coal Gases to Liquid Elemental Sulfur with Monolithic Catalysts

    Energy Technology Data Exchange (ETDEWEB)

    K. C. Kwon

    2006-09-30

    CO components of syngas appear to behave as inert with respect to sulfur formed at the SSRP conditions. One problem in the SSRP process that needs to be eliminated or minimized is COS formation that may occur due to reaction of CO with sulfur formed from the Claus reaction. The objectives of this research are to formulate monolithic catalysts for removal of H{sub 2}S from coal gases and minimum formation of COS with monolithic catalyst supports, {gamma}-alumina wash or carbon coats, and catalytic metals, to develop a catalytic regeneration method for a deactivated monolithic catalyst, to measure kinetics of both direct oxidation of H{sub 2}S to elemental sulfur with SO{sub 2} as an oxidizer and formation of COS in the presence of a simulated coal gas mixture containing H{sub 2}, CO, CO{sub 2}, and moisture, using a monolithic catalyst reactor, and to develop kinetic rate equations and model the direct oxidation process to assist in the design of large-scale plants. This heterogeneous catalytic reaction has gaseous reactants such as H{sub 2}S and SO{sub 2}. However, this heterogeneous catalytic reaction has heterogeneous products such as liquid elemental sulfur and steam. To achieve the above-mentioned objectives using a monolithic catalyst reactor, experiments on conversion of hydrogen sulfide into elemental sulfur and formation of COS were carried out for the space time range of 40-560 seconds at 120-150 C to evaluate effects of reaction temperatures, total pressure, space time, and catalyst regeneration on conversion of hydrogen sulfide into elemental sulfur and formation of COS. Simulated coal gas mixtures consist of 3,600-4,000-ppmv hydrogen sulfide, 1,800-2,000 ppmv sulfur dioxide, 23-27 v% hydrogen, 36-41 v% CO, 10-12 v% CO{sub 2}, 0-10 vol % moisture, and nitrogen as remainder. Volumetric feed rates of a simulated coal gas mixture to the reactor are 30-180 SCCM. The temperature of the reactor is controlled in an oven at 120-150 C. The pressure of the reactor

  2. Conversion of Hydrogen Sulfide in Coal Gases to Liquid Elemental Sulfur with Monolithic Catalysts

    Energy Technology Data Exchange (ETDEWEB)

    K. C. Kwon

    2007-09-30

    CO components of syngas appear to behave as inert with respect to sulfur formed at the SSRP conditions. One problem in the SSRP process that needs to be eliminated or minimized is COS formation that may occur due to reaction of CO with sulfur formed from the Claus reaction. The objectives of this research are to formulate monolithic catalysts for removal of H{sub 2}S from coal gases and minimum formation of COS with monolithic catalyst supports, {gamma}-alumina wash or carbon coats, and catalytic metals, to develop a catalytic regeneration method for a deactivated monolithic catalyst, to measure kinetics of both direct oxidation of H{sub 2}S to elemental sulfur with SO{sub 2} as an oxidizer and formation of COS in the presence of a simulated coal gas mixture containing H{sub 2}, CO, CO{sub 2}, and moisture, using a monolithic catalyst reactor, and to develop kinetic rate equations and model the direct oxidation process to assist in the design of large-scale plants. This heterogeneous catalytic reaction has gaseous reactants such as H{sub 2}S and SO{sub 2}. However, this heterogeneous catalytic reaction has heterogeneous products such as liquid elemental sulfur and steam. Experiments on conversion of hydrogen sulfide into elemental sulfur and formation of COS were carried out for the space time range of 130-156 seconds at 120-140 C to formulate catalysts suitable for the removal of H{sub 2}S and COS from coal gases, evaluate removal capabilities of hydrogen sulfide and COS from coal gases with formulated catalysts, and develop an economic regeneration method of deactivated catalysts. Simulated coal gas mixtures consist of 3,300-3,800-ppmv hydrogen sulfide, 1,600-1,900 ppmv sulfur dioxide, 18-21 v% hydrogen, 29-34 v% CO, 8-10 v% CO{sub 2}, 5-18 vol % moisture, and nitrogen as remainder. Volumetric feed rates of a simulated coal gas mixture to the reactor are 114-132 SCCM. The temperature of the reactor is controlled in an oven at 120-140 C. The pressure of the reactor

  3. Conversion of Hydrogen Sulfide in Coal Gases to Liquid Elemental Sulfur with Monolithic Catalysts

    Energy Technology Data Exchange (ETDEWEB)

    K.C. Kwon

    2009-09-30

    CO components of syngas appear to behave as inert with respect to sulfur formed at the SSRP conditions. One problem in the SSRP process that needs to be eliminated or minimized is COS formation that may occur due to reaction of CO with sulfur formed from the Claus reaction. The objectives of this research are to formulate monolithic catalysts for removal of H{sub 2}S from coal gases and minimum formation of COS with monolithic catalyst supports, {gamma}-alumina wash coat, and catalytic metals, to develop a regeneration method for a deactivated monolithic catalyst, to measure kinetics of both direct oxidation of H{sub 2}S to elemental sulfur with SO{sub 2} as an oxidizer and formation of COS in the presence of a simulated coal gas mixture containing H{sub 2}, CO, CO{sub 2}, and moisture, using a monolithic catalyst reactor. The task of developing kinetic rate equations and modeling the direct oxidation process to assist in the design of large-scale plants will be abandoned since formulation of catalysts suitable for the removal of H{sub 2}S and COS is being in progress. This heterogeneous catalytic reaction has gaseous reactants such as H{sub 2}S and SO{sub 2}. However, this heterogeneous catalytic reaction has heterogeneous products such as liquid elemental sulfur and steam. Experiments on conversion of hydrogen sulfide into elemental sulfur and formation of COS were carried out for the space time range of 46-570 seconds under reaction conditions to formulate catalysts suitable for the removal of H{sub 2}S and COS from coal gases and evaluate their capabilities in reducing hydrogen sulfide and COS in coal gases. Simulated coal gas mixtures consist of 3,200-4,000-ppmv hydrogen sulfide, 1,600-20,000-ppmv sulfur dioxide, 18-27 v% hydrogen, 29-41 v% CO, 8-12 v% CO{sub 2}, 0-10 vol % moisture, and nitrogen as remainder. Volumetric feed rates of simulated coal gas mixtures to the reactor are 30 - 180 cm{sup 3}/min at 1 atm and 25 C (SCCM). The temperature of the reactor is

  4. Conversion of Hydrogen Sulfide in Coal Gases to Liquid Elemental Sulfur with Monolithic Catalysts

    Energy Technology Data Exchange (ETDEWEB)

    K. C. Kwon

    2007-09-30

    CO components of syngas appear to behave as inert with respect to sulfur formed at the SSRP conditions. One problem in the SSRP process that needs to be eliminated or minimized is COS formation that may occur due to reaction of CO with sulfur formed from the Claus reaction. The objectives of this research are to formulate monolithic catalysts for removal of H{sub 2}S from coal gases and minimum formation of COS with monolithic catalyst supports, {gamma}-alumina wash or carbon coats, and catalytic metals, to develop a catalytic regeneration method for a deactivated monolithic catalyst, to measure kinetics of both direct oxidation of H{sub 2}S to elemental sulfur with SO{sub 2} as an oxidizer and formation of COS in the presence of a simulated coal gas mixture containing H{sub 2}, CO, CO{sub 2}, and moisture, using a monolithic catalyst reactor, and to develop kinetic rate equations and model the direct oxidation process to assist in the design of large-scale plants. This heterogeneous catalytic reaction has gaseous reactants such as H{sub 2}S and SO{sub 2}. However, this heterogeneous catalytic reaction has heterogeneous products such as liquid elemental sulfur and steam. Experiments on conversion of hydrogen sulfide into elemental sulfur and formation of COS were carried out for the space time range of 130-156 seconds at 120-140 C to formulate catalysts suitable for the removal of H{sub 2}S and COS from coal gases, evaluate removal capabilities of hydrogen sulfide and COS from coal gases with formulated catalysts, and develop an economic regeneration method of deactivated catalysts. Simulated coal gas mixtures consist of 3,300-3,800-ppmv hydrogen sulfide, 1,600-1,900 ppmv sulfur dioxide, 18-21 v% hydrogen, 29-34 v% CO, 8-10 v% CO{sub 2}, 5-18 vol % moisture, and nitrogen as remainder. Volumetric feed rates of a simulated coal gas mixture to the reactor are 114-132 SCCM. The temperature of the reactor is controlled in an oven at 120-140 C. The pressure of the reactor

  5. Autothermal reforming of biogas over a monolithic catalyst

    Institute of Scientific and Technical Information of China (English)

    Sadao Araki; Naoe Hino; Takuma Mori; Susumu Hikazudani

    2010-01-01

    This study focused on measurement of the autothermal reforming of biogas over a Ni based monolithic catalyst.The effects of the steam/CH4 (S/C) ratio,O2/CH4 (O2/C) ratio and temperature were investigated.The CH4 conversions were higher under all examined temperatures than the equilibrium conversion calculated using the blank outlet temperature,because the catalyst layer was heated by the exothermic catalytic partial oxidation reaction.The CH4 conversion increased with increasing O2/C ratio.Moreover,the CH4 conversion was higher than the equilibrium conversion calculated using the blank outlet temperature for O2/C>0.42 and reached about 100% at O2/C=0.55.However,the hydrogen concentration decreased for O2/C>0.45 because hydrogen was combusted to steam in the presence of excess oxygen.On the other hand,the hydrogen and CO2 concentrations increased and the CO concentration decreased with increasing S/C ratio.As a result,it was found that the highest hydrogen concentrations and CH4 conversions were attained at the O2/C ratios of 0.45-0.55 and the S/C ratios of 1.5-2.5.Moreover,the H2/CO ratio could also be controlled in the range from about 2 to 3.5 to give at least 90% CH4 conversion,by regulating the O2/C or S/C ratios.

  6. Preparation and characterizations of Ce-Cu-O monolithic catalysts for ethyl acetate catalytic combustion

    Institute of Scientific and Technical Information of China (English)

    马瑞红; 苏孝文; 金凌云; 鲁继青; 罗孟飞

    2010-01-01

    Ce-Cu-O monolithic catalysts were prepared by using Ce0.9Cu0.1O1.9 solid solution or nitrate as precursors,and their catalytic performance for the combustion of ethyl acetate were studied.The catalysts calcined at a low temperature showed high catalytic activities.When calcined at high temperatures,the catalyst with Ce0.9Cu0.1O1.9 solid solution as precursor remained a high activity,while the catalyst with metal nitrates as precursors exhibited a suppressed reactivity.Therefore,the catalyst prepared with th...

  7. Conversion of Hydrogen Sulfide in Coal Gases to Liquid Elemental Sulfur with Monolithic Catalysts

    Energy Technology Data Exchange (ETDEWEB)

    K.C. Kwon

    2009-09-30

    CO components of syngas appear to behave as inert with respect to sulfur formed at the SSRP conditions. One problem in the SSRP process that needs to be eliminated or minimized is COS formation that may occur due to reaction of CO with sulfur formed from the Claus reaction. The objectives of this research are to formulate monolithic catalysts for removal of H{sub 2}S from coal gases and minimum formation of COS with monolithic catalyst supports, {gamma}-alumina wash coat, and catalytic metals, to develop a regeneration method for a deactivated monolithic catalyst, to measure kinetics of both direct oxidation of H{sub 2}S to elemental sulfur with SO{sub 2} as an oxidizer and formation of COS in the presence of a simulated coal gas mixture containing H{sub 2}, CO, CO{sub 2}, and moisture, using a monolithic catalyst reactor. The task of developing kinetic rate equations and modeling the direct oxidation process to assist in the design of large-scale plants will be abandoned since formulation of catalysts suitable for the removal of H{sub 2}S and COS is being in progress. This heterogeneous catalytic reaction has gaseous reactants such as H{sub 2}S and SO{sub 2}. However, this heterogeneous catalytic reaction has heterogeneous products such as liquid elemental sulfur and steam. Experiments on conversion of hydrogen sulfide into elemental sulfur and formation of COS were carried out for the space time range of 46-570 seconds under reaction conditions to formulate catalysts suitable for the removal of H{sub 2}S and COS from coal gases and evaluate their capabilities in reducing hydrogen sulfide and COS in coal gases. Simulated coal gas mixtures consist of 3,200-4,000-ppmv hydrogen sulfide, 1,600-20,000-ppmv sulfur dioxide, 18-27 v% hydrogen, 29-41 v% CO, 8-12 v% CO{sub 2}, 0-10 vol % moisture, and nitrogen as remainder. Volumetric feed rates of simulated coal gas mixtures to the reactor are 30 - 180 cm{sup 3}/min at 1 atm and 25 C (SCCM). The temperature of the reactor is

  8. Method for filling a reactor with a catalyst

    DEFF Research Database (Denmark)

    2013-01-01

    The invention relates to a method for filling a reactor with a catalyst for the carbonylation of carbonylated compounds in the gas phase. According to said method, a SILP catalyst is covered with a filling agent which is liquid under normal conditions and is volatile under carbonylation reaction...... conditions, and a thus-treated catalyst is introduced into the reactor and the reactor is sealed....

  9. Steam reforming of n-hexane on pellet and monolithic catalyst beds. A comparative study on improvements due to heat transfer

    Science.gov (United States)

    1981-01-01

    Monolithic catalysts with higher available active surface areas and better thermal conductivity than conventional pellets beds, making possible the steam reforming of fuels heavier than naphtha, were examined. Performance comparisons were made between conventional pellet beds and honeycomb monolith catalysts using n-hexane as the fuel. Metal-supported monoliths were examined. These offer higher structural stability and higher thermal conductivity than ceramic supports. Data from two metal monoliths of different nickel catalyst loadings were compared to pellets under the same operating conditions. Improved heat transfer and better conversion efficiencies were obtained with the monolith having higher catalyst loading. Surface-gas interaction was observed throughout the length of the monoliths.

  10. A monolithic lipase reactor for biodiesel production by transesterification of triacylglycerides into fatty acid methyl esters

    KAUST Repository

    Urban, Jiří T.

    2011-09-26

    An enzymatic reactor with lipase immobilized on a monolithic polymer support has been prepared and used to catalyze the transesterification of triacylglycerides into the fatty acid methyl esters commonly used for biodiesel. A design of experiments procedure was used to optimize the monolithic reactor with variables including control of the surface polarity of the monolith via variations in the length of the hydrocarbon chain in alkyl methacrylate monomer, time of grafting of 1-vinyl-4,4-dimethylazlactone used to activate the monolith, and time used for the immobilization of porcine lipase. Optimal conditions involved the use of a poly(stearyl methacrylate-co-ethylene dimethacrylate) monolith, grafted first with vinylazlactone, then treated with lipase for 2h to carry out the immobilization of the enzyme. Best conditions for the transesterification of glyceryl tributyrate included a temperature of 37°C and a 10min residence time of the substrate in the bioreactor. The reactor did not lose its activity even after pumping through it a solution of substrate equaling 1,000 reactor volumes. This enzymatic reactor was also used for the transesterification of triacylglycerides from soybean oil to fatty acid methyl esters thus demonstrating the ability of the reactor to produce biodiesel. © 2011 Wiley Periodicals, Inc.

  11. A monolithic lipase reactor for biodiesel production by transesterification of triacylglycerides into fatty acid methyl esters.

    Science.gov (United States)

    Urban, Jiri; Svec, Frantisek; Fréchet, Jean M J

    2012-02-01

    An enzymatic reactor with lipase immobilized on a monolithic polymer support has been prepared and used to catalyze the transesterification of triacylglycerides into the fatty acid methyl esters commonly used for biodiesel. A design of experiments procedure was used to optimize the monolithic reactor with variables including control of the surface polarity of the monolith via variations in the length of the hydrocarbon chain in alkyl methacrylate monomer, time of grafting of 1-vinyl-4,4-dimethylazlactone used to activate the monolith, and time used for the immobilization of porcine lipase. Optimal conditions involved the use of a poly(stearyl methacrylate-co-ethylene dimethacrylate) monolith, grafted first with vinylazlactone, then treated with lipase for 2 h to carry out the immobilization of the enzyme. Best conditions for the transesterification of glyceryl tributyrate included a temperature of 37°C and a 10 min residence time of the substrate in the bioreactor. The reactor did not lose its activity even after pumping through it a solution of substrate equaling 1,000 reactor volumes. This enzymatic reactor was also used for the transesterification of triacylglycerides from soybean oil to fatty acid methyl esters thus demonstrating the ability of the reactor to produce biodiesel.

  12. Paraffin Alkylation Using Zeolite Catalysts in a slurry reactor: Chemical Engineering Principles to Extend Catalyst Lifetime

    NARCIS (Netherlands)

    Jong, K.P. de; Mesters, C.M.A.M.; Peferoen, D.G.R.; Brugge, P.T.M. van; Groot, C. de

    1996-01-01

    The alkylation of isobutane with 2-butene is carried out using a zeolitic catalyst in a well stirred slurry reactor. Whereas application of fixed bed technology using a solid acid alkylation catalyst has in the led to catalysts lifetimes in the range of minutes, in this work we report catalyst

  13. Monolithic Catalysts with Low Noble-Metal Content for Exhaust Purification of Small Gasoline Engines

    Institute of Scientific and Technical Information of China (English)

    Zhang Lijuan; Mao Xiaobo; Chen Yaoqiang; Zhong Junbo; Wang Jianli; Zhao Ming; Gong Maochu

    2007-01-01

    A series of low noble-metal content monolithic catalysts for exhaust purification of small gasoline engines was investigated, and it was found that the Pt/Rh-OSM/Al2O3 (where OSM was oxygen storage material) catalyst with Ce0.5Zr0.5-MnOx(3%MnOx) OSM held low light-off temperature for CO, HC, and NO;quite wide three-way window, and outstanding thermal stability. The catalyst could efficiently control exhaust emission of small gasoline engines.

  14. Mapping Reactive Flow Patterns in Monolithic Nanoporous Catalysts

    CERN Document Server

    Falcucci, Giacomo; Montessori, Andrea; Melchionna, Simone; Prestininzi, Pietro; Barroo, Cedric; Bell, David C; Biener, Monika M; Biener, Juergen; Zugic, Branko; Kaxiras, Efthimios

    2016-01-01

    The development of high-efficiency porous catalyst membranes critically depends on our understanding of where the majority of the chemical conversions occur within the porous structure. This requires mapping of chemical reactions and mass transport inside the complex nano-scale architecture of porous catalyst membranes which is a multiscale problem in both the temporal and spatial domain. To address this problem, we developed a multi-scale mass transport computational framework based on the Lattice Boltzmann Method (LBM) that allows us to account for catalytic reactions at the gas-solid interface by introducing a new boundary condition. In good agreement with experiments, the simulations reveal that most catalytic reactions occur near the gas-flow facing side of the catalyst membrane if chemical reactions are fast compared to mass transport within the porous catalyst membrane.

  15. New monolithic enzymatic micro-reactor for the fast production and purification of oligogalacturonides.

    Science.gov (United States)

    Delattre, C; Michaud, P; Vijayalakshmi, M A

    2008-01-15

    Fast production and purification of alpha-(1,4)-oligogalacturonides was investigated using a new enzymatic reactor composed of a monolithic matrix. Pectin lyase from Aspergillus japonicus (Sigma) was immobilized on CIM-disk epoxy monolith. Studies were performed on free pectin lyase and immobilized pectin lyase to compare the optimum temperature, optimum pH, and thermal stability. It was determined that optimum temperature for free pectin lyase and immobilized pectin lyase on monolithic support is 30 degrees C, and optimum pH is 5. Monolithic CIM-disk chromatography is one of the fastest liquid chromatographic method used for separation and purification of biomolecules due to high mass transfer rate. In this context, online one step production and purification of oligogalacturonides was investigated associating CIM-disk pectin lyase and CIM-disk DEAE. This efficient enzymatic bioreactor production of uronic oligosaccharides from polygalacturonic acid (PGA) constitutes an original fast process to generate bioactive oligouronides.

  16. AgI/TiO{sub 2} nanobelts monolithic catalyst with enhanced visible light photocatalytic activity

    Energy Technology Data Exchange (ETDEWEB)

    Yi, Junhui; Huang, Lingling; Wang, Hongjuan; Yu, Hao; Peng, Feng, E-mail: cefpeng@scut.edu.cn

    2015-03-02

    AgI NPs supported on TiO{sub 2} NBs grown on the Ti foil as a monolithic catalyst exhibited excellent visible-light-driven photocatalytic activity, recyclability, and stability for AO-II degradation. - Highlights: • TiO{sub 2} nanobelts (NBs) are grown in-situ on the Ti foil at 150 °C in a KOH solution. • AgI/TiO{sub 2} NBs monolithic catalyst is prepared by a simple method. • AgI/TiO{sub 2} NBs exhibit high visible-light photocatalytic activity for acid orange II degradation. • AgI/TiO{sub 2} NBs have an advantage over the drawback encountered with powder suspension. - Abstract: AgI nanoparticles (NPs) have been decorated on the TiO{sub 2} nanobelts (NBs) immobilized on a metal Ti substrate by a simple impregnating-precipitation method. The as-achieved AgI/TiO{sub 2} monolithic catalyst exhibits a high and stable visible photocatalytic activity toward acid orange II (AO-II) degradation, which is attributed to the suitable energy band match of AgI NPs and TiO{sub 2} NBs, leading to the efficient transfer of photo-generated electrons. In addition, it was found that ·O{sub 2}{sup −} radicals and h{sup +} are the main reactive species for the degradation of AO-II under visible light irradiation. A reasonable photocatalytic mechanism of AgI/TiO{sub 2} photocatalyst toward AO-II degradation was discussed. This monolithic catalyst provides an advantage over the drawback encountered with powder suspension.

  17. Microchannel Reactors for ISRU Applications Using Nanofabricated Catalysts Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Makel Engineering, Inc. (MEI) and USRA propose to develop microchannel reactors for In-Situ Resources Utilization (ISRU) using nanofabricated catalysts. The proposed...

  18. Development of a Monolithic Research Reactor Fuel Type at Argonne National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Clark, C.R.; Briggs, R.J.

    2004-10-06

    The Reduced Enrichment for Research and Test Reactors (RERTR) program has been tasked with the conversion of research reactors from highly enriched to low-enriched uranium (LEU). To convert several high power reactors, monolithic fuel, a new fuel type, is being developed. This fuel type replaces the standard fuel dispersion with a fuel alloy foil, which allows for fuel densities far in excess of that found in dispersion fuel. The single-piece fuel foil also contains a significantly lower interface area between the fuel and the aluminum in the plate than the standard fuel type, limiting the amount of detrimental fuel-aluminum interaction that can occur. Implementation of monolithic fuel is dependant on the development of a suitable fabrication method as traditional roll-bonding techniques are inadequate.

  19. MicroChannel Reactors for ISRU Applications Using Nanofabricated Catalysts

    Science.gov (United States)

    Carranza, Susana; Makel, Darby B.; Vander Wal, Randall L.; Berger, Gordon M.; Pushkarev, Vladimir V.

    2006-01-01

    With the new direction of NASA to emphasize the exploration of the Moon, Mars and beyond, quick development and demonstration of efficient systems for In-Situ Resources Utilization (ISRU) is more critical and timely than ever before. Affordable planning and execution of prolonged manned space missions depend upon the utilization of local resources and the waste products which are formed in manned spacecraft and surface bases. This paper presents current development of miniaturized chemical processing systems that combine microchannel reactor design with nanofabricated catalysts. Carbon nanotubes (CNT) are used to produce a nanostructure within microchannel reactors, as support for catalysts. By virtue of their nanoscale dimensions, nanotubes geometrically restrict the catalyst particle size that can be supported upon the tube walls. By confining catalyst particles to sizes smaller than the CNT diameter, a more uniform catalyst particle size distribution may be maintained. The high dispersion permitted by the vast surface area of the nanoscale material serves to retain the integrity of the catalyst by reducing sintering or coalescence. Additionally, catalytic efficiency increases with decreasing catalyst particle size (reflecting higher surface area per unit mass) while chemical reactivity frequently is enhanced at the nanoscale. Particularly significant is the catalyst exposure. Rather than being confined within a porous material or deposited upon a 2-d surface, the catalyst is fully exposed to the reactant gases by virtue of the nanofabricated support structure. The combination of microchannel technology with nanofabricated catalysts provides a synergistic effect, enhancing both technologies with the potential to produce much more efficient systems than either technology alone. The development of highly efficient microchannel reactors will be applicable to multiple ISRU programs. By selection of proper nanofabricated catalysts, the microchannel reactors can be

  20. Zirconia modified monolithic macroporous Pt/CeO2/Al2O3 catalyst used for water-gas shift reaction

    Institute of Scientific and Technical Information of China (English)

    LIANG Hao; YUAN Honggang; WEI Feng; ZHANG Xiwen; LIU Yuan

    2011-01-01

    Monolithic macroporous Pt/CeO2/Al2O3 and zirconia modified Pt/f eO2/Al2O3 catalysts Were prepared by using concentrated emulsions synthesis route.The catalytic performances over the platinum-based catalysts were investigated by water-gas shift (WGS) reaction in a wide temperature range (180-300 ℃).The samples were characterized with thermogravimetry (TG),X-ray diffraction (XRD),scanning electron microscopy (SEM),high resolution transmission electron microscopy (HRTEM) and temperature programmed reduction (TPR) techniques as well.The SEM and HRTEM results indicated that the monoliths possessed macroporosity,in size of 5-50 μm,and platinum particles were homogeneously dispersed on macroporous materials.XRD and TPR results showed that the interaction between ceria and zirconia oxide was formed and the addition of zirconia could promote the reducibility of platinum oxide on the interface of ceria and zirconia particles,which led to an improvement of catalytic activity in WGS reaction.The results indicated that zirconia modified monolithic macroporous Pt/CeO2/Al2O3 could be fabricated in small size (from millimeter lever to centimeter) and had good reaction activity,which was a potential new route for miniaturization of the WGS reactor.

  1. Advanced Catalytic Hydrogenation Retrofit Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Reinaldo M. Machado

    2002-08-15

    Industrial hydrogenation is often performed using a slurry catalyst in large stirred-tank reactors. These systems are inherently problematic in a number of areas, including industrial hygiene, process safety, environmental contamination, waste production, process operability and productivity. This program proposed the development of a practical replacement for the slurry catalysts using a novel fixed-bed monolith catalyst reactor, which could be retrofitted onto an existing stirred-tank reactor and would mitigate many of the minitations and problems associated with slurry catalysts. The full retrofit monolith system, consisting of a recirculation pump, gas/liquid ejector and monolith catalyst, is described as a monolith loop reactor or MLR. The MLR technology can reduce waste and increase raw material efficiency, which reduces the overall energy required to produce specialty and fine chemicals.

  2. Microchannel Methanation Reactors Using Nanofabricated Catalysts Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Makel Engineering, Inc. (MEI) and the Pennsylvania State University (Penn State) propose to develop and demonstrate a microchannel methanation reactor based on...

  3. Cerium, manganese and cerium/manganese ceramic monolithic catalysts. Study of VOCs and PM removal

    Institute of Scientific and Technical Information of China (English)

    COLMAN-LERNER Esteban; PELUSO Miguel Andrs; SAMBETH Jorge; THOMAS Horacio

    2016-01-01

    Ceramic supported cerium, manganese and cerium-manganese catalysts were prepared by direct impregnation of aqueous precursor, and characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Brunauer-Emmett-Teller method (BET), temperature programmed reduction (H2-TPR), X-ray photoelectron spectroscopy (XPS) acidity measurements and electrical conductivity. The catalytic activity was evaluated for volatile organic compounds (VOC) (ethanol, methyl ethyl ketone and toluene) oxidation. Additionally, catalysts were tested in particulate matter (PM) combustion. The characterization results indicated that Ce was in the form of Ce4+ and Ce3+, and Mn existed in the form of Mn4+and Mn3+on the surface of the Mn/AC sample and in the form of Mn4+ in the Ce/Mn/AC monolith. VOC oxidation results revealed that the Ce/Mn/AC sample showed an excellent performance compared with ceramic supported CeO2 (Ce/AC) and MnOx (Mn/AC) samples. The PM combustion was also higher on Ce/Mn/AC monoliths. The enhanced catalytic activity was mainly attributed to the Ce and Mn interaction which enhanced the acidity, conductiv-ity and the reducibility of the oxides.

  4. A facile method for the preparation of Covalent Triazine Framework coated monoliths as catalyst support - applications in C1 catalysis

    KAUST Repository

    Bavykina, Anastasiya V.

    2017-07-17

    A quasi Chemical Vapour Deposition method for the manufacturing of well-defined Covalent Triazine Framework (CTF) coatings on cordierite monoliths is reported. The resulting supported porous organic polymer is an excellent support for the immobilisation of two different homogeneous catalysts: 1) an IrIIICp*-based catalyst for the hydrogen production from formic acid, and 2) a PtII-based for the direct activation of methane via Periana chemistry. The immobilised catalysts display a much higher activity in comparison with the unsupported CTF operated in slurry because of improved mass transport. Our results demonstrate that CTF based catalysts can be further optimised by engineering at different length-scales.

  5. Influence of Additives Ceria and Lanthana on Performance of Pd/Al/Monolith Honeycomb Catalysts

    Institute of Scientific and Technical Information of China (English)

    田东旭; 王浩静; 王心葵

    2003-01-01

    The effects of ceria and lanthana additives on activity and thermal stabilization of the catalysts for CO oxidation were studied. The results show that the addition of CeO2 clearly improves the catalytic activity, which may derive from the synergic effect between CeO2 and PdO. The catalysts were characterized by means of temperature-programmed reduction (TPR) and X-ray photoelectron spectroscopy (XPS) measurements. The XPS results of a slight increase in metal oxidation state reflect that the charge transfers from metal to ceria and ceria is slightly reduced, which leads to a decrease of the Ce-O bond strength. Pd-Ce synergism affects the reduction behavior of the catalysts. The TPR results show that the CeO2 addition lowers the reduction temperature of PdO, while palladium facilitates the reduction of the ceria. For PdO/La2O3/Al2O3/monolith honeycomb catalysts, the aging test measurements at 1050 ℃ and the XRD results show that the formation of LaAlO3 which neutralizes the surface alumina defects inhibits the sintering of alumina.

  6. Optimal catalyst curves: Connecting density functional theory calculations with industrial reactor design and catalyst selection

    DEFF Research Database (Denmark)

    Jacobsen, C.J.H.; Dahl, Søren; Boisen, A.

    2002-01-01

    For ammonia synthesis catalysts a volcano-type relationship has been found experimentally. We demonstrate that by combining density functional theory calculations with a microkinetic model the position of the maximum of the volcano curve is sensitive to the reaction conditions. The catalytic ammo......-principle quantum mechanical calculations of gas-surface interactions, reactor design, and catalyst selection has been established for the first time....

  7. NUMERICAL SIMULATION FOR MECHANICAL BEHAVIOR OF U10MO MONOLITHIC MINIPLATES FOR RESEARCH AND TEST REACTORS

    Energy Technology Data Exchange (ETDEWEB)

    Hakan Ozaltun & Herman Shen

    2011-11-01

    This article presents assessment of the mechanical behavior of U-10wt% Mo (U10Mo) alloy based monolithic fuel plates subject to irradiation. Monolithic, plate-type fuel is a new fuel form being developed for research and test reactors to achieve higher uranium densities within the reactor core to allow the use of low-enriched uranium fuel in high-performance reactors. Identification of the stress/strain characteristics is important for understanding the in-reactor performance of these plate-type fuels. For this work, three distinct cases were considered: (1) fabrication induced residual stresses (2) thermal cycling of fabricated plates; and finally (3) transient mechanical behavior under actual operating conditions. Because the temperatures approach the melting temperature of the cladding during the fabrication and thermal cycling, high temperature material properties were incorporated to improve the accuracy. Once residual stress fields due to fabrication process were identified, solution was used as initial state for the subsequent simulations. For thermal cycling simulation, elasto-plastic material model with thermal creep was constructed and residual stresses caused by the fabrication process were included. For in-service simulation, coupled fluid-thermal-structural interaction was considered. First, temperature field on the plates was calculated and this field was used to compute the thermal stresses. For time dependent mechanical behavior, thermal creep of cladding, volumetric swelling and fission induced creep of the fuel foil were considered. The analysis showed that the stresses evolve very rapidly in the reactor. While swelling of the foil increases the stress of the foil, irradiation induced creep causes stress relaxation.

  8. Toluene Combustion over Pd-Ce0.4Zr0.6O2 Directly Washcoated Monolithic Catalysts

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A Ce0.4Zr0.6O2 washcoat was prepared using an impregnation method, which acted as a host for the active Pd component to prepare a Pd-Ce0.4Zr0.6O2/substrate monolithic catalyst for toluene combustion.The catalyst was characterized by scanning electron microscopy (SEM), Raman spectroscopy, Brunauner-Emmett-Teller (BET), and carbon monoxide temperature-programmed reduction (CO-TPR).It was found that the washcoat had strong vibration-shock resistance according to an ultrasonic test.The Pd-Ce0.4Zr0.6O2/substrate monolithic catalyst calcined at 400 ℃ showed 95% toluene conversion at a temperature as low as 210 ℃.Furthermore, the lowest temperature for 95% toluene conversion was increased by 40 ℃ after the catalyst calcined at 900 ℃, indicating that the catalyst had good thermal stability.The results revealed that the developed catalyst in this study was promising for eliminating volatile organic compounds (VOCs).

  9. Pilot‐scale investigation and CFD modeling of particle deposition in low‐dust monolithic SCR DeNOx catalysts

    DEFF Research Database (Denmark)

    Heiredal, Michael Lykke; Jensen, Anker Degn; Thøgersen, Joakim Reimer

    2013-01-01

    Deposition of particles in selective catalytic reduction DeNOx monolithic catalysts was studied by low‐dust pilot‐scale experiments. The experiments showed a total deposition efficiency of about 30%, and the deposition pattern was similar to that observed in full‐scale low‐dust applications....... On extended exposure to the dust‐laden flue gas, complete blocking of channels was observed, showing that also in low‐dust applications soot blowing is necessary to keep the catalyst clean. A particle deposition model was developed in computational fluid dynamics, and simulations were carried out assuming...... either laminar or turbulent flow. Assuming laminar flow, the accumulated mass was underpredicted with a factor of about 17, whereas assuming turbulent flow overpredicted the experimental result with a factor of about 2. The simulations showed that turbulent diffusion in the monolith channels and inertial...

  10. Catalyst dynamics: consequences for classical kinetic descriptions of reactors

    DEFF Research Database (Denmark)

    Johannessen, Tue; Larsen, Jane Hvolbæk; Chorkendorff, Ib

    2001-01-01

    The modelling of catalytic reactions/reactors has undergone great improvements since the introduction of empirical power-law kinetics in chemical reaction engineering and micro-kinetic models based on insight into the nature of elementary steps have appeared for many reactions. However, recent...... of the dynamical behaviour of some catalytic systems and discuss the corresponding Limitations in existing models for catalytic reactions and reactors. Catalytic reactors operated in non-steady-state are becoming more frequent in industry. The additional efforts needed to accurately simulate these types...... in situ studies and surface science investigations has brought added attention to the fact that catalysts may behave in a dynamic manner and reconstruct depending on the reaction conditions. This feature severely limits traditional kinetic descriptions. In the present paper, we present examples...

  11. Highly Selective Conversion of Olefin Components in FCC Gasoline to Propylene in Monolithic Catalytic Reactors

    Institute of Scientific and Technical Information of China (English)

    Li Yang; Shao Qian; He Zhenfu; Tian Huiping; Long Jun

    2006-01-01

    The demand for propylene has been growing recently. The concentration of olefins in the gasoline is strictly limited by the related environmental regulations. The olefins contained in the gasoline used as the feed could be cracked into light olefins to slash the olefin concentration in the gasoline to yield more propylene at the same time. The monolithic catalyst washcoated on the modified ZSM-5 zeolite was used in the experiments. The effect of the temperature, the Si/A1 ratio in ZSM-5 and the addition of the rare earth elements on the selectivities and the yields of the light olefins were studied. The high yields of propylene and butene could be obtained under the experimental conditions of a higher temperature and Si/A1 ratio with the addition of rare earth elements.

  12. Simulation of Catalytic Combustion of Methane in a Monolith Honeycomb Reactor%整体式催化及反应器中甲烷燃烧过程的模拟

    Institute of Scientific and Technical Information of China (English)

    梅红; 李成岳; 刘辉; 季生福

    2006-01-01

    Catalytic combustion of CH4/air in monolith reactor is simulated using a commercial computational fluid dynamic code. The user subroutines to describe the heterogeneous reaction at the channel wall in a single channel and at the channel walls in the whole reactor are incorporated into the program. The correctness of the method is verified by comparing the simulation results with the experimental data for the whole reactor. Furthermore, it is observed that the model based on the whole reactor is more reasonable than that based on a single channel. Therefore, using the former, the effects of operating conditions such as inlet gas velocity, temperature, concentration and catalyst loading on methane conversion are investigated.

  13. Combination of Partial Oxidation and CO2 Reforming of Methane over Monolithic Ni/CeO2-ZrO2/γ-Al2O3 Catalyst

    Institute of Scientific and Technical Information of China (English)

    Xuan LI; Yun TENG; Mao Chu GONG; Yao Qiang CHEN

    2005-01-01

    A new monolithic Ni/CeO2-ZrO2/γ-Al2O3 catalyst for combined partial oxidation and CO2 reforming of methane was prepared. The result shows that the addition of O2 to the feed can improve the activity of the catalyst and adjust the H2/CO ratio of the productive gases.

  14. Heterogenized homogeneous catalyst. 3. Oxidation of benzaldehyde in a semibatch tubular wall reactor

    Energy Technology Data Exchange (ETDEWEB)

    Kuo, M.C.; Chou, T.C.

    1987-06-01

    The author's previous works showed that the surface of the heterogenized homogeneous catalyst significantly affects both the initiation and termination of free radicals. To minimize free-radical termination by the surface of catalyst and avoid separation of catalyst from the products in a slurry reactor, a tubular reactor was designed in this work. The termination of free radicals by the surface of catalyst is negligible when the tubular wall reactor is used. The selectivity of perbenzoic acid is very high and the maximum yield of perbenzoic acid is 63%. During the experimental period, no leakage of cobaltic ions was found.

  15. Observed Changes in As-Fabricated U-10Mo Monolithic Fuel Microstructures After Irradiation in the Advanced Test Reactor

    Science.gov (United States)

    Keiser, Dennis; Jue, Jan-Fong; Miller, Brandon; Gan, Jian; Robinson, Adam; Madden, James

    2017-08-01

    A low-enriched uranium U-10Mo monolithic nuclear fuel is being developed by the Material Management and Minimization Program, earlier known as the Reduced Enrichment for Research and Test Reactors Program, for utilization in research and test reactors around the world that currently use high-enriched uranium fuels. As part of this program, reactor experiments are being performed in the Advanced Test Reactor. It must be demonstrated that this fuel type exhibits mechanical integrity, geometric stability, and predictable behavior to high powers and high fission densities in order for it to be a viable fuel for qualification. This paper provides an overview of the microstructures observed at different regions of interest in fuel plates before and after irradiation for fuel samples that have been tested. These fuel plates were fabricated using laboratory-scale fabrication methods. Observations regarding how microstructural changes during irradiation may impact fuel performance are discussed.

  16. Safety analysis of switching between reductive and oxidative conditions in a reaction coupling reverse flow reactor.

    NARCIS (Netherlands)

    van Sint Annaland, M.; Kuipers, J.A.M.; van Swaaij, Willibrordus Petrus Maria

    2001-01-01

    A new reverse flow reactor is developed where endothermic reactants (propane dehydrogenation) and exothermic reactants (fuel combustion) are fed sequentially to a monolithic catalyst, while periodically alternating the inlet and outlet positions. Upon switching from reductive to oxidative conditions

  17. A kinetic rate expression for the time-dependent coke formation rate during propane dehydrogenation over a platinum alumina monolithic catalyst.

    NARCIS (Netherlands)

    van Sint Annaland, M.; Kuipers, J.A.M.; van Swaaij, Willibrordus Petrus Maria

    2001-01-01

    Coke formation rates under propane dehydrogenation reaction conditions on a used monolithic Pt/y-Al2O3 catalyst have been experimentally determined in a thermogravimetric analyser (TGA) as a function of time on stream covering wide temperature and concentration ranges. For relatively short times on

  18. When magnetic catalyst meets magnetic reactor: etherification of FCC light gasoline as an example.

    Science.gov (United States)

    Cheng, Meng; Xie, Wenhua; Zong, Baoning; Sun, Bo; Qiao, Minghua

    2013-01-01

    The application of elaborately designed magnetic catalysts has long been limited to ease their separation from the products only. In this paper, we for the first time employed a magnetic sulphonated poly(styrene-divinylbenzene) resin catalyst on a magnetically stabilized-bed (MSB) reactor to enhance the etherification of fluidized catalytic cracking (FCC) light gasoline, one of the most important reactions in petroleum refining industry. We demonstrated that the catalytic performance of the magnetic acid resin catalyst on the magnetic reactor is substantially enhanced as compared to its performance on a conventional fixed-bed reactor under otherwise identical operation conditions. The magnetic catalyst has the potential to be loaded and unloaded continuously on the magnetic reactor, which will greatly simplify the current complex industrial etherification processes.

  19. R&D and Application of Catalyst for Resid Hydrotreating in Upflow Reactor

    Institute of Scientific and Technical Information of China (English)

    Niu Chuanfeng; Hu Dawei; Dai Lishun; Yang Qinghe

    2008-01-01

    In order to extend the operating cycle of the upflow reactor for resid hydrotreating, the Research Institute of Petroleum Processing taking into account the specifics of resid hydrotreating upflow reactor has developed the high-performance RUF series of catalysts suitable for operation in the upflow reactor. The results of commercial application of catalysts revealed that this RUF series of catalysts loaded after optimized grading could effectively remove metals, sulfur and carbon residue from the residuum to provide improved oil for the following fixed-bed reactor. In the meantime, the RUF series of catalysts have excellent stability to reach an operating cycle of 1.5 years, resulting in minimization of losses caused by refinery downtime.

  20. Study on the correlation between the surface active species of Pd/cordierite monolithic catalyst and its catalytic activity

    Energy Technology Data Exchange (ETDEWEB)

    Liao, Hengcheng, E-mail: hengchengliao@seu.edu.cn; Zuo, Peiyuan; Liu, Miaomiao

    2016-09-15

    Two Pd-loading routes and three Pd-precursor matters were adopted to prepare Pd/(Ce,Y)O{sub 2}/γ-Al{sub 2}O{sub 3}/cordierite monolithic catalyst. The surface active species on the catalyst were characterized by XPS, and its catalytic activity for methane combustion was tested, and the dynamics of the catalytic combustion reaction was also discussed. Pd-loading route and Pd-precursor mass have a significant influence on the catalytic activity and surface active species. The sol dipping method is more advanced than the aqueous solution impregnating method. PN-sol catalyst, by sol dipping combined with Pd(NO{sub 3}){sub 2}-precursor, has the best catalytic activity. The physical reason is the unique active Pd phase coexisting with active PdO phase on the surface, and thus the Pd3d{sub 5/2} binding energy of surface species and apparent activation energy of combustion reaction are considerably decreased. The catalytic activity index, Pd3d{sub 5/2} binding energy and apparent activation energy are highly tied each other with exponential relations.

  1. Miniature fuel cell with monolithically fabricated Si electrodes - Alloy catalyst formation -

    Science.gov (United States)

    Ogura, Daiki; Suzuki, Takahiro; Katayama, Noboru; Dowaki, Kiyoshi; Hayase, Masanori

    2013-12-01

    A novel Pd-Pt catalyst formation process was proposed for reduction of Pt usage. In our miniature fuel cells, porous Pt was used as the catalyst, and the Pt usage was quite high. To reduce the Pt usage, we have attempted to deposit Pt on porous Pd by galvanic replacement, and relatively large output was demonstrated. In this study, in order to reduce more Pt usage and explore the alloy catalyst formation process, atomic layer deposition by UPD-SLRR (Under Potential Deposition - Surface Limited Redox Replacement) was applied to the Pd-Pt catalyst formation. The new process was verified at each process steps by EDS elemental analysis, and the expected spectra were obtained. Prototype cells were constructed by the new process, and cell output was raised to 420mW/cm2 by the Pd-Pt catalyst from 125mW/cm2 with Pd catalyst.

  2. Process for the manufacture of a monolithic support for catalysts suitable for use in controlling carbon monoxide emissions

    Energy Technology Data Exchange (ETDEWEB)

    Paolasini, S.

    1981-07-07

    A monolithic support for a catalyst suitable for use in controlling carbon monoxide emission is prepared by forming a homogeneous, fluid semi-solid mass by admixing colloidal gamma alumina, alpha alumina monohydrate and ceramic fibres with fluidizing and binding agents, water and a mineral acid, said acid being used in an amount sufficient to convert said alpha Al/sub 2/O/sub 3/ monohydrate into a gel, forming the mass into a body of the desired shape, drying the body to substantially remove the added water, at least 10% of said added water being removed at a temperature lower than 50/sup 0/ C., and heat-treating the dried body at 800/sup 0/-1000/sup 0/ C.

  3. Miniature Fuel Cell With Monolithically Fabricated Si Electrodes - Au-Pd-Pt Multilayer Catalyst -

    Science.gov (United States)

    Shirai, Ryo; Vasiljevic, N.; Hayase, Masanori

    2016-11-01

    A novel catalyst layer structure is proposed for our miniature fuel cells. In our fuel cells, conventionally porous Pt was used as a catalyst layer. In order to reduce the Pt amount, instead of porous Pt, porous Pd was formed on a Si chip and Pt was deposited atomically on the Pd by UPD-SLRR(Under Potential Deposition - Surface Limited Redox Replacement). The Pd- Pt catalyst showed satisfying performance, besides high CO tolerance was observed. Though the Pd-Pt catalyst is quite promising, Pd is also a rare metal and reduction of Pd amount is necessary. In this study, a novel Au-Pd-Pt catalyst formation strategy is proposed by UPD-SLRR, and the layered structure is preliminary fabricated.

  4. WATER-GAS SHIFT KINETICS OVER IRON OXIDE CATALYSTS AT MEMBRANE REACTOR CONDITIONS

    Energy Technology Data Exchange (ETDEWEB)

    Carl R.F. Lund

    2002-08-02

    The kinetics of water-gas shift were studied over ferrochrome catalysts under conditions with high carbon dioxide partial pressures, such as would be expected in a membrane reactor. The catalyst activity is inhibited by increasing carbon dioxide partial pressure. A microkinetic model of the reaction kinetics was developed. The model indicated that catalyst performance could be improved by decreasing the strength of surface oxygen bonds. Literature data indicated that adding either ceria or copper to the catalyst as a promoter might impart this desired effect. Ceria-promoted ferrochrome catalysts did not perform any better than unpromoted catalyst at the conditions tested, but copper-promoted ferrochrome catalysts did offer an improvement over the base ferrochrome material. A different class of water-gas shift catalyst, sulfided CoMo/Al{sub 2}O{sub 3} is not affected by carbon dioxide and may be a good alternative to the ferrochrome system, provided other constraints, notably the requisite sulfur level and maximum temperature, are not too limiting. A model was developed for an adiabatic, high-temperature water-gas shift membrane reactor. Simulation results indicate that an excess of steam in the feed (three moles of water per mole of CO) is beneficial even in a membrane reactor as it reduces the rate of adiabatic temperature rise. The simulations also indicate that much greater improvement can be attained by improving the catalyst as opposed to improving the membrane. Further, eliminating the inhibition by carbon dioxide will have a greater impact than will increasing the catalyst activity (assuming inhibition is still operative). Follow-up research into the use of sulfide catalysts with continued kinetic and reactor modeling is suggested.

  5. Cobalt phosphide nanowall arrays supported on carbon cloth: an efficient monolithic non-noble-metal hydrogen evolution catalyst

    Science.gov (United States)

    Yang, Libin; Wang, Kunyang; Du, Gu; Zhu, Wenxin; Cui, Liang; Zhang, Chengxiao; Sun, Xuping; Asiri, Abdullah M.

    2016-11-01

    Hydrogen has been considered as an ideal energy carrier for replacing fossil fuels to mitigate global energy crises. Hydrolysis of sodium borohydride (NaBH4) is simple and effective for hydrogen production but needs active and durable catalysts to accelerate the kinetics. In this paper, we demonstrate that cobalt phosphide nanowall arrays supported on carbon cloth (CoP NAs/CC) efficiently catalyze the hydrolytic dehydrogenation of NaBH4 with an activation energy of 42.1 kJ mol-1 in alkaline media. These monolithic CoP NAs/CC show a maximum hydrogen generation rate of 5960 {{ml}} {{{\\min }}}-1 {{{{g}}}-1}({{CoP})} and are robust with superior durability and reusability. They are also excellent in activity and durability for electrochemical hydrogen evolution in 1.0 M KOH, with the need of an overpotential of only 80 mV to drive 10 mA cm-2. They offer us a promising low-cost hydrogen-generating catalyst for applications.

  6. 蜂窝状催化剂反应器中氢气/空气燃烧的二维模拟%Two-dimensional Simulation for Hydrogen/Air Combustion in a Monolith Reactor

    Institute of Scientific and Technical Information of China (English)

    洪若瑜; 丁剑敏; Vlachos D G

    2005-01-01

    Recent studies on hydrogen combustion were reviewed briefly. The laminar flow and combustion of premixed hydrogen/air mixture in a cylindrical channel of a monolith reactor with and without catalytic wall was numerically modeled by solving two-dimensional (2-D) Navier-Stokes (N-S) equations, energy equation, and species equations. Eight gas species and twenty reversible gas reactions were considered. The control volume technique and the SIMPLE algorithm were used to solve the partial differential equations. The streamlines of the flow field, temperature contours, the entrance length, and the concentration fields were computed. It is found that the entrance zone plays an important role on flow and temperature as well as species distribution. Therefore, the flow cannot be assumed either as fully developed or as plug flow. There is a small but strong thermal expansion zone between the wall and the entrance. Both diffusion and convection affect the heat and mass transfer processes in the expansion zone. Thus the equations of momentum, energy and species conservations should be used to describe hydrogen/air combustion in the monolith reactor. The hot-spot location and concentration field of the homogeneous combustion is strongly influenced by the inlet velocity and temperature, and the equivalence ratio. The catalytic combustion of premixed hydrogen/air mixture over platinum catalyst-coated wall in a cylindrical channel was also simulated.

  7. Progress on Porous Ceramic Membrane Reactors for Heterogeneous Catalysis over Ultrafine and Nano-sized Catalysts

    Institute of Scientific and Technical Information of China (English)

    JIANG Hong; MENG Lie; CHEN Rizhi; JIN Wanqin; XING Weihong; XU Nanping

    2013-01-01

    Heterogeneous catalysts with ultrafine or nano particle size have currently attracted considerable attentions in the chemical and petrochemical production processes,but their large-scale applications remain challenging because of difficulties associated with their efficient separation from the reaction slurry.A porous ceramic membrane reactor has emerged as a promising method to solve the problem concerning catalysts separation in situ from the reaction mixture and make the production process continuous in heterogeneous catalysis.This article presents a review of the present progress on porous ceramic membrane reactors for heterogeneous catalysis,which covers classification of configurations of porous ceramic membrane reactor,major considerations and some important industrial applications.A special emphasis is paid to major considerations in term of application-oriented ceramic membrane design,optimization of ceramic membrane reactor performance and membrane fouling mechanism.Finally,brief concluding remarks on porous ceramic membrane reactors are given and possible future research interests are also outlined.

  8. Catalyst dynamics: consequences for classical kinetic descriptions of reactors

    DEFF Research Database (Denmark)

    Johannessen, Tue; Larsen, Jane Hvolbæk; Chorkendorff, Ib

    2001-01-01

    The modelling of catalytic reactions/reactors has undergone great improvements since the introduction of empirical power-law kinetics in chemical reaction engineering and micro-kinetic models based on insight into the nature of elementary steps have appeared for many reactions. However, recent...... of the dynamical behaviour of some catalytic systems and discuss the corresponding Limitations in existing models for catalytic reactions and reactors. Catalytic reactors operated in non-steady-state are becoming more frequent in industry. The additional efforts needed to accurately simulate these types...... of reactors are discussed. Finally, we discuss the role of computational fluid dynamics (CFD) as a tool for detailed simulation of catalytic reactors....

  9. Coke- and sintering-resistant monolithic catalysts derived from in situ supported hydrotalcite-like films on Al wires for dry reforming of methane

    Science.gov (United States)

    Du, Xianjun; Zhang, Dengsong; Shi, Liyi; Gao, Ruihua; Zhang, Jianping

    2013-03-01

    Monolithic catalysts derived from in situ supported hydrotalcite-like films on Al wires display high resistance to coke formation and sintering in the dry reforming of methane due to their hierarchical porous structure, well dispersed metallic nickel species, more basic sites and strong metal-support interaction effect.Monolithic catalysts derived from in situ supported hydrotalcite-like films on Al wires display high resistance to coke formation and sintering in the dry reforming of methane due to their hierarchical porous structure, well dispersed metallic nickel species, more basic sites and strong metal-support interaction effect. Electronic supplementary information (ESI) available: Experimental details, XRD patterns, SEM images, and TEM images. See DOI: 10.1039/c3nr33921a

  10. Co-Assembled Supported Catalysts: Synthesis of Nano-Structured Supported Catalysts with Hierarchic Pores through Combined Flow and Radiation Induced Co-Assembled Nano-Reactors

    OpenAIRE

    Galip Akay

    2016-01-01

    A novel generic method of silica supported catalyst system generation from a fluid state is presented. The technique is based on the combined flow and radiation (such as microwave, thermal or UV) induced co-assembly of the support and catalyst precursors forming nano-reactors, followed by catalyst precursor decomposition. The transformation from the precursor to supported catalyst oxide state can be controlled from a few seconds to several minutes. The resulting nano-structured micro-porous s...

  11. Improved catalytic performance of Ni catalysts for steam methane reforming in a micro-channel reactor

    Institute of Scientific and Technical Information of China (English)

    Bozhao Chu; Nian Zhang; Xuli Zhai; Xin Chen; Yi Cheng

    2014-01-01

    Milliseconds process to produce hydrogen by steam methane reforming (SMR) reaction, based on Ni catalyst rather than noble catalyst such as Pd, Rh or Ru, in micro-channel reactors has been paid more and more attentions in recent years. This work aimed to further improve the catalytic performance of nickel-based catalyst by the introduction of additives, i.e., MgO and FeO, prepared by impregnation method on the micro-channels made of metal-ceramic complex substrate. The prepared catalysts were tested in the same micro-channel reactor by switching the catalyst plates. The results showed that among the tested catalysts Ni-Mg catalyst had the highest activity, especially under harsh conditions, i.e., at high space velocity and/or low reaction temperature. Moreover, the catalyst activity and selectivity were stable during the 12 h on stream test even when the ratio of steam to carbon (S/C) was as low as 1.0. The addition of MgO promoted the active Ni species to have a good dispersion on the substrate, leading to a better catalytic performance for SMR reaction.

  12. Modeling of Isobutane/Butene Alkylation Using Solid Acid Catalysts in a Fixed Bed Reactor

    Institute of Scientific and Technical Information of China (English)

    Liu Zheng; Tang Xiaojin; Hu Lifeng; Hou Shuandi

    2016-01-01

    A dynamic mass transfer model of isobutane/butene alkylation over solid acid catalysts in a ifxed bed reactor was established. In the model, a modiifed equation for the relationship between point activity and effective diffusion coefifcient was proposed. It is found that the simulation results ift the experimental data well and the breakthrough time of the bed layer is predicted accurately. By modeling the alkylation process, the time-space distribution of butene and point activity proifles of catalysts can be obtained. Furthermore, the reasons for the deactivation of solid acid catalysts were investigated. It indicates that the main reason for the deactivation of catalysts is the site coverage near the inlet of the reactor, while it is ascribed to the steric effect in the region far away from the inlet.

  13. Session 4: A novel catalyst improves hydrogen production in a membrane reactor

    Energy Technology Data Exchange (ETDEWEB)

    Munera, J.; Kihn, M.; Carrara, C.; Irusta, S.; Cornaglia, L.M.; Lombardo, E.A. [Instituto de Investigaciones en Catalisis y Petroquimica (FIQ, UNL-CONICET), Santa Fe-Argentina (Argentina)

    2004-07-01

    The dry reforming of methane as a source of H{sub 2} has been performed using a commercial Ni catalyst and supported Ru, Pd, Ir and Pt catalysts in a hydrogen-permeable membrane reactor. The main problems encountered in this application are the abundant formation of coke, deleterious to the membrane, and catalyst deactivation. Appropriate catalysts preventing carbon deposits formation are needed to avoid membrane damage. In this work, we report the results obtained with a novel catalyst, Rh/La{sub 2}O{sub 3}-SiO{sub 2}, and with Rh/La{sub 2}O{sub 3}. Both the fresh and used catalysts were characterized by DRX, FTIR, BET, Laser Raman spectroscopy and hydrogen chemisorption. The effect of the operation variables upon the performance of the membrane reactor were also studied. The obtained results have shown that the Rh catalysts are very stable under reaction conditions while the presence of tiny amounts of graphite only detectable through LRS does not endanger membrane stability. In all cases, the methane conversions are higher than the thermodynamic values but the best performing formulation (highest Rh dispersion) was obtained using the composite La{sub 2}O{sub 3}-SiO{sub 2} support. (O.M.)

  14. Magnetically stabilized bed reactor for selective hydrogenation of olefins in reformate with amorphous nickel alloy catalyst

    Institute of Scientific and Technical Information of China (English)

    Xuhong Mu; Enze Min

    2007-01-01

    A magnetically stabilized bed (MSB) reactor for selective hydrogenation of olefins in reformate was developed by combining the advantages of MSB and amorphous nickel alloy catalyst. The effects of operating conditions, such as temperature, pressure, liquid space velocity, hydrogen-to-oil ratio, and magnetic field intensity on the reaction were studied. A mathematical model of MSB reactor for hydrogenation of olefins in reformate was established. A reforming flow scheme with a post-hydrogenation MSB reactor was proposed. Finally, MSB hydrogenation was compared with clay treatment and conventional post-hydrogenation.

  15. A packed bed membrane reactor for production of biodiesel using activated carbon supported catalyst.

    Science.gov (United States)

    Baroutian, Saeid; Aroua, Mohamed K; Raman, Abdul Aziz A; Sulaiman, Nik M N

    2011-01-01

    In this study, a novel continuous reactor has been developed to produce high quality methyl esters (biodiesel) from palm oil. A microporous TiO2/Al2O3 membrane was packed with potassium hydroxide catalyst supported on palm shell activated carbon. The central composite design (CCD) of response surface methodology (RSM) was employed to investigate the effects of reaction temperature, catalyst amount and cross flow circulation velocity on the production of biodiesel in the packed bed membrane reactor. The highest conversion of palm oil to biodiesel in the reactor was obtained at 70 °C employing 157.04 g catalyst per unit volume of the reactor and 0.21 cm/s cross flow circulation velocity. The physical and chemical properties of the produced biodiesel were determined and compared with the standard specifications. High quality palm oil biodiesel was produced by combination of heterogeneous alkali transesterification and separation processes in the packed bed membrane reactor. Copyright © 2010 Elsevier Ltd. All rights reserved.

  16. Optimal catalyst curves: Connecting density functional theory calculations with industrial reactor design and catalyst selection

    DEFF Research Database (Denmark)

    Jacobsen, C.J.H.; Dahl, Søren; Boisen, A.

    2002-01-01

    For ammonia synthesis catalysts a volcano-type relationship has been found experimentally. We demonstrate that by combining density functional theory calculations with a microkinetic model the position of the maximum of the volcano curve is sensitive to the reaction conditions. The catalytic...... ammonia synthesis activity, to a first approximation, is a function only of the binding energy of nitrogen to the catalyst. Therefore, it is possible to evaluate which nitrogen binding energy is optimal under given reaction conditions. This leads to the concept of optimal catalyst curves, which illustrate...... the nitrogen binding energies of the optimal catalysts at different temperatures, pressures, and synthesis gas compositions. Using this concept together with the ability to prepare catalysts with desired binding energies it is possible to optimize the ammonia process. In this way a link between first...

  17. In-situ reduction of a methanol synthesis catalyst in a three-phase slurry reactor

    Energy Technology Data Exchange (ETDEWEB)

    Sawant, A.; Ko, M.K.; Parameswaran, V.; Lee, S.; Kulik, C.J.

    1987-01-01

    A new method for the reduction of metal oxide catalysts (CuO, ZnO, Al/sub 2/O/sub 3/) has been developed for liquid phase methanol synthesis. The reducing agent is a 5% hydrogen in nitrogen mixture and the operation is carried out at 446.09 KPa. This method makes it possible to reduce finely crushed catalyst (-100 + 120 mesh) in a three phase slurry reactor. This method offers several advantages over methods in which the catalyst is reduced in a gas-solid contact mode and then slurried for use. The catalyst has been shown to be very effectively reduced and reaches its full production capacity after reduction.

  18. The origin of a large apparent tortuosity factor for the Knudsen diffusion inside monoliths of a samaria-alumina aerogel catalyst: a diffusion NMR study.

    Science.gov (United States)

    Mueller, R; Zhang, S; Klink, M; Bäumer, M; Vasenkov, S

    2015-11-01

    Pulsed field gradient (PFG) NMR was applied to measure tortuosity factors for carbon dioxide diffusion in the Knudsen and gas regimes inside monoliths of a samaria-alumina aerogel catalyst, a high porosity material containing micropores in addition to meso- and macropores. The apparent tortuosity factor obtained from PFG NMR measurements for the Knudsen diffusion in the meso- and macropores of the catalyst has an unexpectedly large value of approximately 6 if carbon dioxide adsorption in the micropores and other types of surface adsorption sites of the catalyst is ignored. At the same time, the corresponding apparent tortuosity factor in the gas regime was found to be around 2. Application of a proposed model which describes fast molecular exchange between the surface adsorption sites and the main pore volume of the catalyst yields corrected tortuosity factors which depend only on the pore system geometry. Using this model, the corrected tortuosity factors were found to be around 2 for both diffusion regimes, in agreement with the expectations based on a high porosity of the studied catalyst.

  19. Low temperature catalytic combustion of propane over Pt-based catalyst with inverse opal microstructure in a microchannel reactor.

    Science.gov (United States)

    Guan, Guoqing; Zapf, Ralf; Kolb, Gunther; Men, Yong; Hessel, Volker; Loewe, Holger; Ye, Jianhui; Zentel, Rudolf

    2007-01-21

    A novel Pt-based catalyst with highly regular, periodic inverse opal microstructure was fabricated in a microchannel reactor, and catalytic testing revealed excellent conversion and stable activity for propane combustion at low temperatures.

  20. Co-Assembled Supported Catalysts: Synthesis of Nano-Structured Supported Catalysts with Hierarchic Pores through Combined Flow and Radiation Induced Co-Assembled Nano-Reactors

    Directory of Open Access Journals (Sweden)

    Galip Akay

    2016-05-01

    Full Text Available A novel generic method of silica supported catalyst system generation from a fluid state is presented. The technique is based on the combined flow and radiation (such as microwave, thermal or UV induced co-assembly of the support and catalyst precursors forming nano-reactors, followed by catalyst precursor decomposition. The transformation from the precursor to supported catalyst oxide state can be controlled from a few seconds to several minutes. The resulting nano-structured micro-porous silica supported catalyst system has a surface area approaching 300 m2/g and X-ray Diffraction (XRD-based catalyst size controlled in the range of 1–10 nm in which the catalyst structure appears as lamellar sheets sandwiched between the catalyst support. These catalyst characteristics are dependent primarily on the processing history as well as the catalyst (Fe, Co and Ni studied when the catalyst/support molar ratio is typically 0.1–2. In addition, Ca, Mn and Cu were used as co-catalysts with Fe and Co in the evaluation of the mechanism of catalyst generation. Based on extensive XRD, Scanning Electron Microscopy (SEM and Transmission Electron Microscopy (TEM studies, the micro- and nano-structure of the catalyst system were evaluated. It was found that the catalyst and silica support form extensive 0.6–2 nm thick lamellar sheets of 10–100 nm planar dimensions. In these lamellae, the alternate silica support and catalyst layer appear in the form of a bar-code structure. When these lamellae structures pack, they form the walls of a micro-porous catalyst system which typically has a density of 0.2 g/cm3. A tentative mechanism of catalyst nano-structure formation is provided based on the rheology and fluid mechanics of the catalyst/support precursor fluid as well as co-assembly nano-reactor formation during processing. In order to achieve these structures and characteristics, catalyst support must be in the form of silane coated silica nano

  1. Catalyst-Packed Non-Thermal Plasma Reactor for Removal of Nitrogen Oxides

    Science.gov (United States)

    Ravi, V.; Young, Sun Mok; Rajanikanth, B. S.; Kang, Ho-Chul

    2003-02-01

    A single-stage plasma-catalytic reactor in which catalytic materials were packed was used to remove nitrogen oxides. The packing material was scoria being made of various metal oxides including Al2O3, MgO, TiO2, etc. Scoria was able to act not only as dielectric pellets but also as a catalyst in the presence of reducing agent such as ethylene and ammonia. Without plasma discharge, scoria did not work well as a catalyst in the temperature range of 100 °C to 200 °C, showing less than 10% of NOx removal efficiency. When plasma is produced inside the reactor, the NOx removal efficiency could be increased to 60% in this temperature range.

  2. Catalytic wet air oxidation of phenol over CeO2-TiO2 catalyst in the batch reactor and the packed-bed reactor.

    Science.gov (United States)

    Yang, Shaoxia; Zhu, Wanpeng; Wang, Jianbing; Chen, Zhengxiong

    2008-05-30

    CeO2-TiO2 catalysts are prepared by coprecipitation method, and the activity and stability in the catalytic wet air oxidation (CWAO) of phenol are investigated in a batch reactor and packed-bed reactor. CeO2-TiO2 mixed oxides show the higher activity than pure CeO2 and TiO2, and CeO2-TiO2 1/1 catalyst displays the highest activity in the CWAO of phenol. In a batch reactor, COD and TOC removals are about 100% and 77% after 120 min in the CWAO of phenol over CeO2-TiO2 1/1 catalyst at reaction temperature of 150 degrees C, the total pressure of 3 MPa, phenol concentration of 1000 mg/L, and catalyst dosage of 4 g/L. In a packed-bed reactor using CeO2-TiO2 1/1 particle catalyst, over 91% COD and 80% TOC removals are obtained at the reaction temperature of 140 degrees C, the air total pressure of 3.5 MPa, the phenol concentration of 1000 mg/L for 100 h continue reaction. Leaching of metal ions of CeO2-TiO2 1/1 particle catalyst is very low during the continuous reaction. CeO2-TiO2 1/1 catalyst exhibits the excellent activity and stability in the CWAO of phenol.

  3. Biodiesel production in a membrane reactor using MCM-41 supported solid acid catalyst.

    Science.gov (United States)

    Xu, Wei; Gao, Lijing; Wang, Songcheng; Xiao, Guomin

    2014-05-01

    Production of biodiesel from the transesterification between soybean oil and methanol was conducted in this study by a membrane reactor, in which ceramic membrane was packed with MCM-41 supported p-toluenesulfonic acid (PTSA). Box-Behnken design and response surface methodology (RSM) were used to investigate the effects of reaction temperature, catalyst amount and circulation velocity on the yield of biodiesel. A reduced cubic model was developed to navigate the design space. Reaction temperature was found to have most significant effect on the biodiesel yield while the interaction of catalyst amount and circulation velocity have minor effect on it. 80°C of reaction temperature, 0.27 g/cm(3) of catalyst amount and 4.15 mL/min of circulation velocity were proved to be the optimum conditions to achieve the highest biodiesel yield. Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. Synthesis of Biodiesel in Batch and Packed-Bed Reactors Using Powdered and Granular Sugar Catalyst

    Science.gov (United States)

    Janaun, J.; Lim, P. M.; Balan, W. S.; Yaser, A. Z.; Chong, K. P.

    2017-06-01

    Increasing world production of palm oil warrants effective utilization of its waste. In particular, conversion of waste cooking oil into biodiesel has obtained global interest because of renewable energy need and reduction of CO2 emission. In this study, oleic acid used as a model compound for waste cooking oil conversion using esterification reaction catalysed by sugar catalyst (SC) in powdered (P-SC) and granular (G-SC) forms. The catalysts were synthesized via incomplete carbonization of D-glucose followed by functionalization with concentrated sulphuric acid. Catalysts characterizations were done for their physical and chemical properties using modern tools. Batch and packed-bed reactor systems were used to evaluate the reactivity of the catalysts. The results showed that G-SC had slightly higher total acidity and more porous than P-SC. The experimental conditions for batch reaction were temperature of 60°C, molar ratio of 1:20 (Oleic Acid:Methanol) and 2 wt. catalyst with respect to oleic acid. The results showed the maximum oleic acid conversion using G-SC and P-SC were 52 and 48, respectively. Whereas, the continuous reaction with varying feed flow rate as a function of retention time was studied by using 3 g of P-SC in 60 °C and 1:20 molar ratio in a packed-bed reactor. The results showed that a longer retention time which was 6.48 min and feed flow rate 1.38 ml/min, achieved higher average conversion of 9.9 and decreased with further increasing flow rate. G-SC showed a better average conversion of 10.8 at lowest feed flow rate of 1.38 ml/min in continuous reaction experiments. In a broader perspective, large scale continuous biodiesel production is feasible using granular over powdered catalyst mainly due to it lower pressure drop.

  5. Novel high-temperature reactors for in situ studies of three-way catalysts using turbo-XAS.

    Science.gov (United States)

    Guilera, Gemma; Gorges, Bernard; Pascarelli, Sakura; Vitoux, Hugo; Newton, Mark A; Prestipino, Carmelo; Nagai, Yasutaka; Hara, Naoyuki

    2009-09-01

    Two novel high-temperature reactors for in situ X-ray absorption spectroscopy (XAS) measurements in fluorescence are presented, each of them being optimized for a particular purpose. The powerful combination of these reactors with the turbo-XAS technique used in a dispersive-XAS beamline permits the study of commercial three-way catalysts under realistic gas composition and temporal conditions.

  6. Hydrogen Production from Glycerol Steam Reforming over Monolithic Catalyst%整体式催化剂上甘油水蒸气重整制氢

    Institute of Scientific and Technical Information of China (English)

    汪丛伟; 于乃超; 阴秀丽; 吴创之

    2014-01-01

    The effect of coating composition and its proportion on the physicochemical properties of monolithic cata-lyst and its catalytic performance in the glycerol steam reforming reaction was investigated. By examining the influ-ence of molar ratio of Ce to Zr,as well as adding La,on catalyst activity,the optimal condition was determined to be the mole ratio of Ce-Zr-La being 1∶1∶1. The monolithic catalyst activities were obviously improved. Underthe condition of glycerin concentration of 10%,space velocity of 3.07,h-1,glycerin can convert completely into gas product within the temperature range;whilst the hydrogen selectivity increased gradually,then leveled off,with a maximum of 90.85%. With the increase of the space velocity and concentration of glycerol,the hydrogen selectivity and the gas phase conversion of monolithic catalyst decreased,but its catalytic performance can still remaingood enough for application.%为改善甘油重整制氢反应在转化率、氢产率以及抑制积碳方面都与热力学平衡存在较大差距的问题,设计开发了整体式重整催化剂.考察了涂层组分、比例对整体式催化剂理化特性及其在甘油水蒸气重整制氢反应中催化性能的影响.通过考察Ce-Zr物质的量比及La的添加对催化剂活性的影响,确定了Ce-Zr-La物质的量比为1∶1∶1为最优条件.整体式催化剂的活性得到明显改善,在甘油质量分数为10%,空速为3.07,h-1时,在温度考察范围内甘油完全转化为气相产物,氢气选择性递增,并趋于平稳,最高可达90.85%;随着空速增大,甘油质量分数的增加,氢气选择性减小,甘油气相转化率降低,但仍可保持较好的转化效果.

  7. Attrition resistant catalyst for dimethyl ether synthesis in fluidized-bed reactor

    Institute of Scientific and Technical Information of China (English)

    Li-hua TENG

    2008-01-01

    Fluidized-bed reactor is a candidate for dimethyi ether(DME)synthesis from syngas because of its excellent heat removal capability.In Order to improve the attrition resistance of catalyst,an amount of silica sol as binder was added to the catalyst composed of methanol synthesis component CuO/ZnO/Al2O3 and methanol dehydration component HZSM-5,which was prepared by coprecipitation and shaped by spray drying to get spherical particles.The effect of silica sol on the catalytic activity was investigated in a fixed-bed flow microreactor.Based on the experiment results,silica sol in the range of 0~20wt% had small effect on the catalytie activity.Generally,the CO conversion and DME yield decreased with the increase in concen.tration of silica sol,while the attrition resistance of catalysts increased with increasing silica sol,indicating that it was feasible to improve the attrition resistance without greatly sacrificing the activity of catalyst.In addition,the characterizations of catalysts were carried out using Brunauer-Emmett-Teller(BET),X-ray powder diffraction(XRD)and temperature programmed reduction (TPR).

  8. Isobutane/2-butene alkylation over potential heterogeneous catalysts in a slurry reactor

    Energy Technology Data Exchange (ETDEWEB)

    Roervik, T.

    1996-12-31

    The trend towards more effective use of fossil fuels and reduced environmental pollution represents a major task of improvement within the refinery processes. The highly isomerized and high octane paraffins produced from isobutane and light olefins by alkylation fulfill all the requirements for reformulated gasoline. This doctoral thesis discusses new catalyst systems because of their potential in alkylation. A slurry reactor apparatus for solid-acid catalysed isobutane/butene alkylation was developed and used to investigate the performance of various heterogeneous catalysts. The selected materials were mainly zeolite types with faujasite structures. The samples were characterized by various methods before alkylation. In general, the order of decreasing catalyst activity after 3 h of reaction at 80{sup o}C was found to be: H-EMT >> H-FAU, dealuminated H-FAU >> NS.500, TA-Y, CeY-98 > Nafion-H. The order of decreasing alkylate selectivity of the catalysts was: H-EMT >> dealuminated H-FAU > H-FAU >> Nafion-H > CeY-98 > TA-Y > H-SAPO-37, NS.500. H-EMT was the most promising system for further development, also because of the very low formation of the undesirable isooctenes and a high selectivity towards isooctanes among the alkylates. A high density of accessible strong acid sites was found to be essential for a high alkylation activity and selectivity. Open structure, like hexagonal faujasite, was advantageous. The distribution of trimethylpentanes formed in zeolites was ascribed to pore restrictions as a major factor. The effect of operating conditions on catalyst performance was investigated statistically, and a high dilution of butene in the slurry reactor was found to be very important. 153 refs., 40 figs., 12 tabs.

  9. Design of slurry bubble column reactors: novel technique for optimum catalyst size selection contractual origin of the invention

    Science.gov (United States)

    Gamwo, Isaac K [Murrysville, PA; Gidaspow, Dimitri [Northbrook, IL; Jung, Jonghwun [Naperville, IL

    2009-11-17

    A method for determining optimum catalyst particle size for a gas-solid, liquid-solid, or gas-liquid-solid fluidized bed reactor such as a slurry bubble column reactor (SBCR) for converting synthesis gas into liquid fuels considers the complete granular temperature balance based on the kinetic theory of granular flow, the effect of a volumetric mass transfer coefficient between the liquid and the gas, and the water gas shift reaction. The granular temperature of the catalyst particles representing the kinetic energy of the catalyst particles is measured and the volumetric mass transfer coefficient between the gas and liquid phases is calculated using the granular temperature. Catalyst particle size is varied from 20 .mu.m to 120 .mu.m and a maximum mass transfer coefficient corresponding to optimum liquid hydrocarbon fuel production is determined. Optimum catalyst particle size for maximum methanol production in a SBCR was determined to be in the range of 60-70 .mu.m.

  10. A stable, novel catalyst improves hydrogen production in a membrane reactor

    Energy Technology Data Exchange (ETDEWEB)

    Irusta, S.; Munera, J.; Carrara, C.; Lombardo, E.A.; Cornaglia, L.M. [Instituto de Investigaciones en Catalisis y Petroquimica FIQ, UNL-CONICET, Santiago del Estero 2829, 3000 Santa Fe (Argentina)

    2005-06-22

    The dry reforming of methane as a source of H{sub 2} was performed using a well-known catalyst, Rh/La{sub 2}O{sub 3}, together with a novel one, Rh/La{sub 2}O{sub 3}-SiO{sub 2}, in a hydrogen-permeable membrane reactor. The catalysts were characterized by XRD, TPR, FTIR, H{sub 2} and CO chemisorption. In all lanthanum-based catalysts, the activity remained constant after 100h on stream at 823K. The basis of their high stability could be traced back to the strong metal-support interaction (TPR) in Rh/La{sub 2}O{sub 3} catalysts. The La{sub 2}O{sub 3}-SiO{sub 2} solids are also stable even though a weaker rhodium-lanthanum interaction (TPR) can be observed. The incorporation of the promoter (La{sub 2}O{sub 3}) to the silica support induces a parallel increase in the metal dispersion (CO adsorption). The effect of the operation variables upon the performance of the membrane reactor was also studied. The novel Rh (0.6%)/La{sub 2}O{sub 3} (27%)-SiO{sub 2} catalyst proved to be the best formulation. Operating the membrane reactor at 823K, both methane and CO{sub 2} conversions were 40% higher than the equilibrium values, producing 0.5mol H{sub 2}/mol CH{sub 4}. This catalyst, tested at W/F three times lower than Rh (0.6%)/La{sub 2}O{sub 3}, showed a similar performance. Both the increase of the sweep gas flow rate and the decrease of the permeation area significantly affected methane conversion and H{sub 2} production. The presence of tiny amounts of graphite only detectable through LRS did not endanger membrane stability. The better performance of Rh (0.6%)/La{sub 2}O{sub 3} (27%)-SiO{sub 2} is related to the high dispersion.

  11. Catalysts with Cerium in a Membrane Reactor for the Removal of Formaldehyde Pollutant from Water Effluents.

    Science.gov (United States)

    Gutiérrez-Arzaluz, Mirella; Noreña-Franco, Luis; Ángel-Cuevas, Saúl; Mugica-Álvarez, Violeta; Torres-Rodríguez, Miguel

    2016-05-24

    We report the synthesis of cerium oxide, cobalt oxide, mixed cerium, and cobalt oxides and a Ce-Co/Al₂O₃ membrane, which are employed as catalysts for the catalytic wet oxidation (CWO) reaction process and the removal of formaldehyde from industrial effluents. Formaldehyde is present in numerous waste streams from the chemical industry in a concentration low enough to make its recovery not economically justified but high enough to create an environmental hazard. Common biological degradation methods do not work for formaldehyde, a highly toxic but refractory, low biodegradability substance. The CWO reaction is a recent, promising alternative that also permits much lower temperature and pressure conditions than other oxidation processes, resulting in economic benefits. The CWO reaction employing Ce- and Co-containing catalysts was carried out inside a slurry batch reactor and a membrane reactor. Experimental results are reported. Next, a mixed Ce-Co oxide film was supported on an γ-alumina membrane used in a catalytic membrane reactor to compare formaldehyde removal between both types of systems. Catalytic materials with cerium and with a relatively large amount of cerium favored the transformation of formaldehyde. Cerium was present as cerianite in the catalytic materials, as indicated by X-ray diffraction patterns.

  12. Catalysts with Cerium in a Membrane Reactor for the Removal of Formaldehyde Pollutant from Water Effluents

    Directory of Open Access Journals (Sweden)

    Mirella Gutiérrez-Arzaluz

    2016-05-01

    Full Text Available We report the synthesis of cerium oxide, cobalt oxide, mixed cerium, and cobalt oxides and a Ce–Co/Al2O3 membrane, which are employed as catalysts for the catalytic wet oxidation (CWO reaction process and the removal of formaldehyde from industrial effluents. Formaldehyde is present in numerous waste streams from the chemical industry in a concentration low enough to make its recovery not economically justified but high enough to create an environmental hazard. Common biological degradation methods do not work for formaldehyde, a highly toxic but refractory, low biodegradability substance. The CWO reaction is a recent, promising alternative that also permits much lower temperature and pressure conditions than other oxidation processes, resulting in economic benefits. The CWO reaction employing Ce- and Co-containing catalysts was carried out inside a slurry batch reactor and a membrane reactor. Experimental results are reported. Next, a mixed Ce–Co oxide film was supported on an γ-alumina membrane used in a catalytic membrane reactor to compare formaldehyde removal between both types of systems. Catalytic materials with cerium and with a relatively large amount of cerium favored the transformation of formaldehyde. Cerium was present as cerianite in the catalytic materials, as indicated by X-ray diffraction patterns.

  13. Development of monolith with a carbon-nanofiber-washcoat as a structured catalyst support in liquid phase

    NARCIS (Netherlands)

    Jarrah, Nabeel A.; Ommen, van J.G.; Lefferts, L.

    2003-01-01

    Washcoats with improved mass transfer properties are necessary to circumvent concentration gradients in case of fast reactions in liquid phase, e.g. nitrate hydrogenation. A highly porous, high surface area (180 m2/g) and thin washcoat of carbon fibers, was produced on a monolith support by methane

  14. Synthesis of Biodiesel Using ZrO2 Polycrystalline Ceramic Foam Catalyst in a Tubular Reactor

    Institute of Scientific and Technical Information of China (English)

    Wang Yunpu; Fan Liangliang; Dai Leilei; Liu Yuhuan; Ruan Roger; Liu Shitao; Zhang Xueqin; Wan Yiqin

    2015-01-01

    With the help of the ceramic foam research efforts and preparation techniques, the ZrO2 polycrystalline ceramic foam catalyst was synthesized, and its characteristics, including the crystal structure, the phase composition, the acid–base properties, and the microstructure, were analyzed by XRD, SEM, Py-IR, and BET techniques. The performance of the ZrO2 polycrystalline ceramic foam catalyst in a tubular reactor was investigated via biodiesel synthesis using S. wilsoniana oil and methanol. The effects of reaction conditions (i.e., reaction temperature, reaction pressure, and volume ratio of methanol to S. wilsoniana oil) on transesteriifcation efifciency were investigated, and the reaction conditions were optimized using RSM. The optimum reaction temperature, reaction pressure, and volume ratio of methanol to S. wilsoniana oil were de-termined to be 290℃, 10 MPa, and 4:1, respectively. Under this condition, the FAME content in the product oil reached 98.38%. The performance of the ZrO2 polycrystalline ceramic foam catalyst synthesized in this work for biodiesel synthesis from S. wilsoniana oil with a moisture content of 7.1%and an acid value of 130.697 mg KOH/g was examined, and the FAME content in the product oil was found to be 93%and 97.67%, respectively. The FAME content in the product oil ex-ceeded 97%after ifve consecutive cycles (12 h per cycle of use) of the catalyst. The proposed catalyst represents a new type of solid catalyst with excellent acid resistance, water resistance, esteriifcation efifciency, and catalytic stability.

  15. Dynamic modeling of a H2O-permselective membrane reactor to enhance methanol synthesis from syngas considering catalyst deactivation

    Institute of Scientific and Technical Information of China (English)

    M.Farsi; A.Jahanmiri

    2012-01-01

    In this paper,the effect of water vapor removal on methanol synthesis capacity from syngas in a fixed-bed membrane reactor is studied considering long-term catalyst deactivation.A dynamic heterogeneous one-dimensional mathematical model that is composed of two sides is developed to predict the performance of this configuration.In this configuration,conventional methanol reactor is supported by an aluminasilica composite membrane layer for water vapor removal from reaction zone.To verify the accuracy of the considered model and assumptions,simulation results of the conventional methanol reactor is compared with the industrial plant data under the same process condition.The membrane reactor improves catalyst life time and enhances CO2 conversion to methanol by overcoming the limitation imposed by thermodynamic equilibrium.This configuration has enhanced the methanol production capacity about 4.06% compared with the industrial methanol reactor during the production time.

  16. CARBON COATED (CARBONOUS) CATALYST IN EBULLATED BED REACTOR FOR PRODUCTION OF OXYGENATED CHEMICALS FROM SYNGAS/CO2

    Energy Technology Data Exchange (ETDEWEB)

    Peizheng Zhou

    2001-10-26

    There are a number of exothermic chemical reactions which might benefit from the temperature control and freedom from catalyst fouling provided by the ebullated bed reactor technology. A particularly promising area is production of oxygenated chemicals, such as alcohols and ethers, from synthesis gas, which can be economically produced from coal or biomass. The ebullated bed operation requires that the small-diameter ({approx}1/32 inch) catalyst particles have enough mechanical strength to avoid loss by attrition. However, all of the State Of The Art (SOTA) catalysts and advanced catalysts for the purpose are low in mechanical strength. The patented carbon-coated catalyst technology developed in our laboratory converts catalyst particles with low mechanical strength to strong catalysts suitable for ebullated bed application. This R&D program is concerned with the modification on the mechanical strength of the SOTA and advanced catalysts so that the ebullated bed technology can be utilized to produce valuable oxygenated chemicals from syngas/CO{sub 2} efficiently and economically. The objective of this R&D program is to study the technical and economic feasibility of selective production of high-value oxygenated chemicals from synthesis gas and CO{sub 2} mixed feed in an ebullated bed reactor using carbon-coated catalyst particles.

  17. CARBON COATED (CARBONOUS) CATALYST IN EBULLATED BED REACTOR FOR PRODUCTION OF OXYGENATED CHEMICALS FROM SYNGAS/CO2

    Energy Technology Data Exchange (ETDEWEB)

    Peizheng Zhou

    2000-11-17

    There are a number of exothermic chemical reactions which might benefit from the temperature control and freedom from catalyst fouling provided by the ebullated bed reactor technology. A particularly promising area is production of oxygenated chemicals, such as alcohols and ethers, from synthesis gas, which can be economically produced from coal or biomass. The ebullated bed operation requires that the small-diameter ({approx} 1/32 inch) catalyst particles have enough mechanical strength to avoid loss by attrition. However, all of the State Of The Art (SOTA) catalysts and advanced catalysts for the purpose are low in mechanical strength. The patented carbon-coated catalyst technology developed in our laboratory converts catalyst particles with low mechanical strength to strong catalysts suitable for ebullated bed application. This R&D program is concerned with the modification on the mechanical strength of the SOTA and advanced catalysts so that the ebullated bed technology can be utilized to produce valuable oxygenated chemicals from syngas/CO{sub 2} efficiently and economically. The objective of this R&D program is to study the technical and economic feasibility of selective production of high-value oxygenated chemicals from synthesis gas and CO{sub 2} mixed feed in an ebullated bed reactor using carbon-coated catalyst particles.

  18. Catalyst-Packed Non-Thermal Plasma Reactor for Removal of Nitrogen Oxides

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    A single-stage plasma-catalytic reactor in which catalytic materials were packedwas used to remove nitrogen oxides. The packing material was scoria being made of various metaloxides including A12O3, MgO, TiO2, etc. Scoria was able to act not only as dielectric pelletsbut also as a catalyst in the presence of reducing agent such as ethylene and ammonia. Withoutplasma discharge, scoria did not work well as a catalyst in the temperature range of 100 °Cto 200 °C, showing less than 10% of NOx removal efficiency. When plasma is produced inside thereactor, the NOx removal efficiency could be increased to 60% in this temperature range.

  19. Transesterification of propylene glycol methyl ether in chromatographic reactors using anion exchange resin as a catalyst.

    Science.gov (United States)

    Oh, Jungmin; Sreedhar, Balamurali; Donaldson, Megan E; Frank, Timothy C; Schultz, Alfred K; Bommarius, Andreas S; Kawajiri, Yoshiaki

    2016-09-30

    Reactive chromatography using an anion exchange resin is proposed for a transesterification reaction of propylene glycol methyl ether (DOWANOL™ PM) with ethyl acetate to produce propylene glycol methyl ether acetate (DOWANOL™ PMA). This reaction is studied in batch and chromatographic reactors catalyzed by an anion exchange resin. Several anion exchange resins are tested and compared based on the performance of resin as an adsorbent and a catalyst. A chromatographic column is packed with a selected catalyst, AMBERLITE™ IRA904, and both reaction and chromatographic elution are studied at different temperatures and feed concentrations. The resulting chromatograms are fitted to a mathematical model to obtain adsorption equilibrium and reaction kinetic parameters by the inverse method. Compared to esterification investigated in a previous study, transesterification has advantages such as a higher conversion at lower temperature and easy removal of the byproduct which may lead to higher productivity. Deactivation of anion exchange resins is observed and potential solutions are suggested.

  20. Hydrogen production in membrane reactors using Rh catalysts on binary supports

    Energy Technology Data Exchange (ETDEWEB)

    Carrara, Carlos; Roa, Alejandro; Cornaglia, Laura; Lombardo, Eduardo A. [Instituto de Investigaciones en Catalisis y Petroquimica (FIQ, UNL-CONICET), Sgo del Estero 2829-3000 Santa Fe (Argentina); Mateos-Pedrero, Cecilia; Ruiz, Patricio [Unite de Catalyse et Chimie des Materiaux Divises, Universite Catholique de Louvain, Place Croix du Sud 2/17, 1348 Louvain-la Neuve (Belgium)

    2008-04-15

    The binary supports employed in this work were prepared by different methods. The Ti(7%)-MgO and the Ti(13%)-SiO{sub 2} were obtained using the grafting technique. The La(27%)-SiO{sub 2} was obtained through the incipient wetness impregnation with La(NO{sub 3}){sub 3} of Aerosil 300, previously calcined at 1173 K. The Rh was incorporated to these supports by wet impregnation. The catalysts were first evaluated for the CH{sub 4} + CO{sub 2} reaction in a fixed-bed reactor. They were found to be active and stable as to justify their use in the membrane reactor, which was operated at 823 K achieving methane conversions up to twice as much as the equilibrium values. In all cases, the activity of the Rh solids remained constant after 120 h on stream with very little formation of carbonaceous residues only detected through LRS. The catalysts were characterized through either hydrogen or carbon monoxide chemisorption, TPR, XRD, LRS and XPS. The Rh(0.6)/La-SiO{sub 2} catalyst showed a high metal dispersion that remained constant after use and the highest capacity to restore the CH{sub 4} + CO{sub 2} equilibrium when H{sub 2} was permeated out of the reaction section. The Rh(0.8)/Ti-MgO showed the highest Rh/oxide interaction associated with the lowest capacity to restore the reaction equilibrium. The Rh(0.8)/Ti-SiO{sub 2} exhibited an intermediate activity due in part to the partial segregation of the TiO{sub 2} upon calcinations and the subsequent appearance of small Rh crystallites in the used catalysts. (author)

  1. Hydrogen production by catalytic decomposition of methane using a Fe-based catalyst in a fluidized bed reactor

    Institute of Scientific and Technical Information of China (English)

    D.Torres; S.de Llobet; J.L.Pinilla; M.J.Lázaro; I.Suelves; R.Moliner

    2012-01-01

    Catalytic decomposition of methane using a Fe-based catalyst for hydrogen production has been studied in this work.A Fe/Al2O3 catalyst previously developed by our research group has been tested in a fluidized bed reactor (FBR).A parametric study of the effects of some process variables,including reaction temperature and space velocity,is undertaken.The operating conditions strongly affect the catalyst performance.Methane conversion was increased by increasing the temperature and lowering the space velocity.Using temperatures between 700 and 900 ℃ and space velocities between 3 and 6 LN/(gcat·h),a methane conversion in the range of 25%-40% for the gas exiting the reactor could be obtained during a 6 h run.In addition,carbon was deposited in the form of nanofilaments (chain like nanofibers and multiwall nanotubes) with similar properties to those obtained in a fixed bed reactor.

  2. Continuous preparation of carbon-nanotube-supported platinum catalysts in a flow reactor directly heated by electric current

    Directory of Open Access Journals (Sweden)

    Alicja Schlange

    2011-10-01

    Full Text Available In this contribution we present for the first time a continuous process for the production of highly active Pt catalysts supported by carbon nanotubes by use of an electrically heated tubular reactor. The synthesized catalysts show a high degree of dispersion and narrow distributions of cluster sizes. In comparison to catalysts synthesized by the conventional oil-bath method a significantly higher electrocatalytic activity was reached, which can be attributed to the higher metal loading and smaller and more uniformly distributed Pt particles on the carbon support. Our approach introduces a simple, time-saving and cost-efficient method for fuel cell catalyst preparation in a flow reactor which could be used at a large scale.

  3. Dynamic photocatalytic reduction of CO{sub 2} to CO in a honeycomb monolith reactor loaded with Cu and N doped TiO{sub 2} nanocatalysts

    Energy Technology Data Exchange (ETDEWEB)

    Tahir, Muhammad, E-mail: mtahir@cheme.utm.my; Tahir, Beenish

    2016-07-30

    Highlights: • Cu-N/TiO{sub 2} catalysts and cordierite honeycomb monolith tested for CO{sub 2} reduction. • Cu/TiO{sub 2} yielded 14 times higher CO than the N/TiO{sub 2} and 64 times than TiO{sub 2}. • N/TiO{sub 2} was suitable for trapping holes and favored dynamic CH{sub 4} formation. • Cu/TiO{sub 2} gave negative effect on CH{sub 4} production, but enhanced dynamic CO yield. • Cordierite honeycomb support enhanced CO{sub 2} reduction with improved selectivity. - Abstract: Cordierite honeycomb monoliths loaded with N/TiO{sub 2} and Cu/TiO{sub 2} nanocatalysts for dynamic photocatalytic CO{sub 2} reduction with H{sub 2} to CO in a continuous photoreactor illuminated with UV-light irradiations have been investigated. The nanocatalysts, loaded over the monoliths channels using sol-gel dip-coating method, were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), N{sub 2} adsorption-desorption, X-ray photoelectron spectroscopy (XPS), UV–vis diffuse reflectance and photoluminescence (PL) analysis. Crystalline and anatase TiO{sub 2} structure with nanoparticles evenly supported over the cordierite monolith channels were observed. Cu and N presented over TiO{sub 2}, shifted band gap energy towards visible region and hindered charges recombination rate. Loading Cu and N greatly improved TiO{sub 2} photoactivity for dynamic CO{sub 2} reduction to CO. Due to high photoactivity and selectivity, Cu/TiO{sub 2} assisted system yielded 14 times higher CO than the N/TiO{sub 2} and 64 times the amount of copper observed over pure TiO{sub 2} in a continuous operation of photoreactor. This significant improvement in Cu/TiO{sub 2} activity was noticeable due to efficient trapping and transport of electrons by Cu-metal. With unique properties, N/TiO{sub 2} showed good activity for continuous CO{sub 2} reduction to CH{sub 4}. In addition, a photocatalytic reaction mechanism is proposed to understand the experimental results over Cu

  4. Catalytic wet air oxidation of coke-plant wastewater on ruthenium-based eggshell catalysts in a bubbling bed reactor.

    Science.gov (United States)

    Yang, M; Sun, Y; Xu, A H; Lu, X Y; Du, H Z; Sun, C L; Li, C

    2007-07-01

    Catalytic wet air of coke-plant wastewater was studied in a bubbling bed reactor. Two types of supported Ru-based catalysts, eggshell and uniform catalysts, were employed. Compared with the results in the wet air oxidation of coke-plant wastewater, supported Ru uniform catalysts showed high activity for chemical oxygen demand (COD) and ammonia/ammonium compounds (NH3-N) removal at temperature of 250 degrees C and pressure of 4.8 MPa, and it has been demonstrated that the catalytic activity of uniform catalyst depended strongly on the distribution of active sites of Ru on catalyst. Compared to the corresponding uniform catalysts with the same Ru loading (0.25 wt.% and 0.1 wt.%, respectively), the eggshell catalysts showed higher activities for CODcr removal and much higher activities for NH3-N degradation. The high activity of eggshell catalyst for treatment of coke-plant wastewater can be attributed to the higher density of active Ru sites in the shell layer than that of the corresponding uniform catalyst with the same Ru loading. It has been also evidenced that the active Ru sites in the internal core of uniform catalyst have very little or no contribution to CODcr and NH3-N removal in the total oxidation of coke-plant wastewater.

  5. Catalytic combustion of propane in a membrane reactor with separate feed of reactants - III. Role of catalyst load on reactor performance

    NARCIS (Netherlands)

    Saracco, G; Veldsink, JW; Versteeg, GF; van Swaaij, WPM

    1996-01-01

    This paper deals with a pilot plant study on the catalytic combustion of propane in a membrane reactor with separate feed of reactants. The importance of the amount of catalyst (1% b.w. Pt on gamma-Al2O3), deposited on the pore walls of the membrane, is investigated. Two membranes were prepared by

  6. Complete dechlorination of pentachlorophenol using palladized bacterial cellulose in a rotating catalyst contact reactor.

    Science.gov (United States)

    Patel, Upendra D; Suresh, Sumathi

    2008-03-15

    A rotating catalyst contact reactor (RCCR) was developed which consisted of palladized bacterial cellulose immobilized on acrylic discs for hydrodechlorination of pentachlorophenol (PCP). More than 99% of 40 mg L(-1) PCP was dechlorinated to phenol in the presence of hydrogen in batch mode at initial pH values of 5.5 and 6.5 within 2 h of reaction with stoichiometric release of free chloride. The rate of PCP dechlorination was found to be independent of rotational speed of discs. PCP (40 mg L(-1)) hydrodechlorination experiments were also conducted using RCCR in continuous flow mode at hydraulic retention times of 1 and 2 h. The average outlet PCP concentrations revealed that liquid phase in RCCR closely resembled that of a continuous flow complete mix reactor (CFMR). Approximately 12 and 11 L of 40 mg L(-1) PCP (pH 6.5) could be treated in RCCR with 99 and 80% efficiencies in batch and continuous flow modes, respectively without any appreciable loss of the catalytic activity. These results suggested reusability of palladized bacterial cellulose which in turn is expected to substantially reduce the cost of treatment process. Thus RCCR seems to have high potential for treatment of ground water contaminated with chlorinated organic compounds. Dried palladized bacterial cellulose has been used as a material for electrodes in a fuel cell. However, its application as a hydrodechlorination catalyst in a reactor operating under room temperature and atmospheric pressure has not been reported to the best of our knowledge. Scanning electron microscopy, energy dispersive X-ray spectroscopy and X-ray diffraction analyses suggested the irreversible deposition of palladium (Pd 0) particles on the bacterial cellulose fibrils.

  7. PREPARATION AND PERFORMANCE OF MONOLITHIC CATALYST FOR TAR CRACKING%整体式焦油裂解催化剂的制备及性能研究

    Institute of Scientific and Technical Information of China (English)

    鲁敏; 吕鹏梅; 袁振宏; 李惠文; 许敬亮

    2011-01-01

    以堇青石为载体,采用真空浸渍法制备整体式镍基催化剂,研究了不同干燥方法对整体式催化剂内表面活性组分轴向分布的影响及不同工艺条件下的催化性能.结果表明:微波干燥法所得催化剂内表面活性组分轴向分布最均匀;重时空速对焦油裂解率的影响较大,当重时空速为177kg/(h·m3)时,焦油裂解率高达92.62%,H2的体积分数为46.53%;在较低温度条件(700~800℃)下,催化温度对焦油裂解的影响较小,当催化温度上升到900℃时,焦油裂解率大幅上升,单位质量生物质气体产率高达1.22Nm3/kg.%The Ni-based monolithic catalyst was prepared by vacuum impregnation with the support of cordierite. The influences of different drying methods to the axial distribution of active constituent in monolithic catalyst internal surface and the catalytic performance under different process conditions was studied. The results show that the axial distribution of catalyst internal surface active constituent is more homogeneous after microwaves drying. The weight hour space velocity (WHSV) has great influence on tar cracking rate. When the WHSV is 177kg/(h·m3), the tar cracking rate is 92.62% and H2 volume content is 46.53%. When the catalytic temperature is between 700 ~ 800℃, the variety of tar cracking rate is small, but when catalytic temperature rises to 900℃, the tar cracking rate can increase greatly and the gas yield can reach 1.22Nm3/kg per dried biomass.

  8. CARBON COATED (CARBONOUS) CATALYST IN EBULLATED BED REACTOR FOR PRODUCTION OF OXYGENATED CHEMICALS FROM SYNGAS/CO2

    Energy Technology Data Exchange (ETDEWEB)

    Peizheng Zhou

    2002-12-30

    This report summarizes the work completed under DOE's Support of Advanced Fuel Research program, Contract No. DE-FG26-99FT40681. The contract period was October 2000 through September 2002. This R&D program investigated the modification of the mechanical strength of catalyst extrudates using Hydrocarbon Technologies, Inc. (HTI) carbon-coated catalyst technology so that the ebullated bed technology can be utilized to produce valuable oxygenated chemicals from syngas/CO{sub 2} efficiently and economically. Exothermic chemical reactions benefit from the temperature control and freedom from catalyst fouling provided by the ebullated bed reactor technology. The carbon-coated extrudates prepared using these procedures had sufficient attrition resistance and surface area for use in ebullated bed operation. The low cost of carbon coating makes the carbon-coated catalysts highly competitive in the market of catalyst extrudates.

  9. Dynamic photocatalytic reduction of CO2 to CO in a honeycomb monolith reactor loaded with Cu and N doped TiO2 nanocatalysts

    Science.gov (United States)

    Tahir, Muhammad; Tahir, Beenish

    2016-07-01

    Cordierite honeycomb monoliths loaded with N/TiO2 and Cu/TiO2 nanocatalysts for dynamic photocatalytic CO2 reduction with H2 to CO in a continuous photoreactor illuminated with UV-light irradiations have been investigated. The nanocatalysts, loaded over the monoliths channels using sol-gel dip-coating method, were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), N2 adsorption-desorption, X-ray photoelectron spectroscopy (XPS), UV-vis diffuse reflectance and photoluminescence (PL) analysis. Crystalline and anatase TiO2 structure with nanoparticles evenly supported over the cordierite monolith channels were observed. Cu and N presented over TiO2, shifted band gap energy towards visible region and hindered charges recombination rate. Loading Cu and N greatly improved TiO2 photoactivity for dynamic CO2 reduction to CO. Due to high photoactivity and selectivity, Cu/TiO2 assisted system yielded 14 times higher CO than the N/TiO2 and 64 times the amount of copper observed over pure TiO2 in a continuous operation of photoreactor. This significant improvement in Cu/TiO2 activity was noticeable due to efficient trapping and transport of electrons by Cu-metal. With unique properties, N/TiO2 showed good activity for continuous CO2 reduction to CH4. In addition, a photocatalytic reaction mechanism is proposed to understand the experimental results over Cu and N modified TiO2 catalysts in a continuous operation of photoreactor.

  10. Challenges in polyoxometalate-mediated aerobic oxidation catalysis: catalyst development meets reactor design.

    Science.gov (United States)

    Lechner, Manuel; Güttel, Robert; Streb, Carsten

    2016-11-14

    Selective catalytic oxidation is one of the most widely used chemical processes. Ideally, highly active and selective catalysts are used in combination with molecular oxygen as oxidant, leading to clean, environmentally friendly process conditions. For homogeneous oxidation catalysis, molecular metal oxide anions, so-called polyoxometalates (POMs) are ideal prototypes which combine high reactivity and stability with chemical tunability on the molecular level. Typically, POM-mediated aerobic oxidations are biphasic, using gaseous O2 and liquid reaction mixtures. Therefore, the overall efficiency of the reaction is not only dependent on the chemical components, but requires chemical engineering insight to design reactors with optimized productivity. This Perspective shows that POM-mediated aerobic liquid-phase oxidations are ideal reactions to be carried out in microstructured flow reactors as they enable facile mass and energy transfer, provide large gas-liquid interfaces and can be easily upscaled. Recent advances in POM-mediated aerobic catalytic oxidations are therefore summarized with a focus on technological importance and mechanistic insight. The principles of reactor design are discussed from a chemical engineering point of view with a focus on homogeneous oxidation catalysis using O2 in microfluidic systems. Further, current limitations to catalytic activity are identified and future directions based on combined chemistry and chemical engineering approaches are discussed to show that this approach could lead to sustainable production methods in industrial chemistry based on alternative energy sources and chemical feedstocks.

  11. Correlation of Microstructure, Rheological and Morphological Characteristics of Synthesized Polypropylene (PP Reactor Blends Using Homogeneous Binary Metallocene Catalyst

    Directory of Open Access Journals (Sweden)

    Javid Vaezi

    2017-02-01

    Full Text Available A novel binary homogeneous catalyst system based on (I: rac-Me2Si(2-Me-4-PhIn2ZrCl2 and (II: (2-PhIn2ZrCl2 catalysts at various molar ratios was utilized for the synthesis of polypropylene (PP reactor blends with bimodal molecular weight distribution (MWD. The results of gel permeation chromatography analyses revealed that the catalyst (I was responsible for the production of i-PP with high molecular weight (MW while the individual use of catalyst (II led to the production of an elastomeric PP with relatively low MW. However, application of the binary catalyst system led to high MW bimodal MWD products being highly dependent on the catalysts’ molar ratios. Increasing the molar ratio of catalyst (II to catalyst (I resulted in a notable enhancement of the products’ complex viscosity due to the increased MW, a higher level of chains’ entanglements and formation of amorphous blocks along the polymer chains. All products exhibited a single relaxation that shifted towards longer times upon changing the catalysts’ molar ratios. Scanning electron microscopy results revealed that the fracture surface of the blends, synthesized by the binary catalyst system, became more heterogeneous in comparison with the products obtained by the individual use of the catalyst (I. The observed heterogeneity was found to increase by increasing the amount of catalyst (II. Such morphological change was further corroborated by the dynamic rheological data, indicating a promising correlation between the linear rheological results and the morphological features of the synthesized PP reactor blends.

  12. Steam reforming of methanol over oxide decorated nanoporous gold catalysts: a combined in situ FTIR and flow reactor study.

    Science.gov (United States)

    Shi, J; Mahr, C; Murshed, M M; Gesing, T M; Rosenauer, A; Bäumer, M; Wittstock, A

    2017-03-29

    Methanol as a green and renewable resource can be used to generate hydrogen by reforming, i.e., its catalytic oxidation with water. In combination with a fuel cell this hydrogen can be converted into electrical energy, a favorable concept, in particular for mobile applications. Its realization requires the development of novel types of structured catalysts, applicable in small scale reactor designs. Here, three different types of such catalysts were investigated for the steam reforming of methanol (SRM). Oxides such as TiO2 and CeO2 and mixtures thereof (Ce1Ti2Ox) were deposited inside a bulk nanoporous gold (npAu) material using wet chemical impregnation procedures. Transmission electron and scanning electron microscopy reveal oxide nanoparticles (1-2 nm in size) abundantly covering the strongly curved surface of the nanoporous gold host (ligaments and pores on the order of 40 nm in size). These catalysts were investigated in a laboratory scaled flow reactor. First conversion of methanol was detected at 200 °C. The measured turn over frequency at 300 °C of the CeOx/npAu catalyst was 0.06 s(-1). Parallel investigation by in situ infrared spectroscopy (DRIFTS) reveals that the activation of water and the formation of OHads are the key to the activity/selectivity of the catalysts. While all catalysts generate sufficient OHads to prevent complete dehydrogenation of methanol to CO, only the most active catalysts (e.g., CeOx/npAu) show direct reaction with formic acid and its decomposition to CO2 and H2. The combination of flow reactor studies and in operando DRIFTS, thus, opens the door to further development of this type of catalyst.

  13. Application of a Homogeneous Dodecakis[NCN-Pincer-PdII] Catalyst in a Nanofiltration Membrane Reactor under Continious Reaction Conditions

    NARCIS (Netherlands)

    Koten, G. van; Dijkstra, H.P.; Ronde, N.; Klink, G.P.M. van; Vogt, D.

    2003-01-01

    A shape-persistent nanosize dodecakis(NCN-PdII-aqua) complex (4b) was applied as a homogeneous catalyst in the double Michael reaction between methyl vinyl ketone and ethyl -cyanoacetate under continuous reaction conditions in a nanofiltration membrane reactor. Due to its macromolecular dimensions,

  14. FeCrO Nanoparticles as Anode Catalyst for Ethane Proton Conducting Fuel Cell Reactors to Coproduce Ethylene and Electricity

    Directory of Open Access Journals (Sweden)

    Jian-Hui Li

    2011-01-01

    Full Text Available Ethylene and electrical power are cogenerated in fuel cell reactors with FeCr2O4 nanoparticles as anode catalyst, La0.7Sr0.3FeO3- (LSF as cathode material, and BaCe0.7Zr0.1Y0.2O3- (BCZY perovskite oxide as proton-conducting ceramic electrolyte. FeCr2O4, BCZY and LSF are synthesized by a sol-gel combustion method. The power density increases from 70 to 240 mW cm−2, and the ethylene yield increases from about 14.1% to 39.7% when the operating temperature of the proton-conducting fuel cell reactor increases from 650∘C to 750∘C. The FeCr2O4 anode catalyst exhibits better catalytic performance than nanosized Cr2O3 anode catalyst.

  15. Reactors

    CERN Document Server

    International Electrotechnical Commission. Geneva

    1988-01-01

    This standard applies to the following types of reactors: shunt reactors, current-limiting reactors including neutral-earthing reactors, damping reactors, tuning (filter) reactors, earthing transformers (neutral couplers), arc-suppression reactors, smoothing reactors, with the exception of the following reactors: small reactors with a rating generally less than 2 kvar single-phase and 10 kvar three-phase, reactors for special purposes such as high-frequency line traps or reactors mounted on rolling stock.

  16. Alkali resistivity of Cu based selective catalytic reduction catalysts

    DEFF Research Database (Denmark)

    Putluru, Siva Sankar Reddy; Jensen, Anker Degn; Riisager, Anders;

    2012-01-01

    The deactivation of V2O5–WO3–TiO2, Cu–HZSM5 and Cu–HMOR plate type monolithic catalysts was investigated when exposed to KCl aerosols in a bench-scale reactor. Fresh and exposed catalysts were characterized by selective catalytic reduction (SCR) activity measurements, scanning electron microscope...... catalysts revealed that the potassium salt not only deposited on the catalyst surface, but also penetrated into the catalyst wall. Thus, the K/M ratio (M = V or Cu) was high on V2O5–WO3–TiO2 catalyst and comparatively less on Cu–HZSM5 and Cu–HMOR catalysts. NH3-TPD revealed that the KCl exposed Cu–HZSM5...

  17. Ruthenium promotion of Co/SBA-15 catalysts for Fischer-Tropsch synthesis in slurry-phase reactors

    Institute of Scientific and Technical Information of China (English)

    Jocielys Jovelino Rodrigues; Gina Pecchi; Fabiano André Narciso Fernandes; Meiry Gláucia Freire Rodrigues

    2012-01-01

    The aim of this work was to evaluate the catalytic properties of a Ru promoted Co/SBA-15 catalyst for Fischer-Tropsch synthesis (FTS).The Ru promoted Co/SBA-15 catalyst was prepared by wet impregnation method and was characterized by X-ray diffraction,X-ray energy dispersion spectrophotometer,N2 adsorption-desorption,temperature-programmed reduction and transmission electron microscopy.The Fischer-Tropsch synthesis using the catalyst was carried out to evaluate the catalyst activity and its effect on FTS product distribution.The synthesis was carried out in a slurry reactor operating at 513 K,20 atm,CO ∶ H2 molar ratio of 1 ∶ 1.X-ray diffraction showed that the calcined cobalt catalyst did not modify the structure of SBA-15,proving that Co was present in the form of Co3O4 in the catalyst.The addition of cobalt in SBA-15 decreased the specific superficial area of the molecular sieve.Fischer-Tropsch synthesis activity and C5+ hydrocarbon selectivity increased with the addition of Ru.The increases in activity and selectivity were attributed to the increased number of active sites resulting from higher reducibility and the synergetic effect of Ru and Co.Ru/Co/SBA-15 catalysts showed moderate conversion (40%) and high selectivity towards the production of C5+ (80 wt%).

  18. Visible-Light-Responsive Photocatalysis: Ag-Doped TiO2 Catalyst Development and Reactor Design Testing

    Science.gov (United States)

    Coutts, Janelle L.; Hintze, Paul E.; Meier, Anne; Shah, Malay G.; Devor, Robert W.; Surma, Jan M.; Maloney, Phillip R.; Bauer, Brint M.; Mazyck, David W.

    2016-01-01

    In recent years, the alteration of titanium dioxide to become visible-light-responsive (VLR) has been a major focus in the field of photocatalysis. Currently, bare titanium dioxide requires ultraviolet light for activation due to its band gap energy of 3.2 eV. Hg-vapor fluorescent light sources are used in photocatalytic oxidation (PCO) reactors to provide adequate levels of ultraviolet light for catalyst activation; these mercury-containing lamps, however, hinder the use of this PCO technology in a spaceflight environment due to concerns over crew Hg exposure. VLR-TiO2 would allow for use of ambient visible solar radiation or highly efficient visible wavelength LEDs, both of which would make PCO approaches more efficient, flexible, economical, and safe. Over the past three years, Kennedy Space Center has developed a VLR Ag-doped TiO2 catalyst with a band gap of 2.72 eV and promising photocatalytic activity. Catalyst immobilization techniques, including incorporation of the catalyst into a sorbent material, were examined. Extensive modeling of a reactor test bed mimicking air duct work with throughput similar to that seen on the International Space Station was completed to determine optimal reactor design. A bench-scale reactor with the novel catalyst and high-efficiency blue LEDs was challenged with several common volatile organic compounds (VOCs) found in ISS cabin air to evaluate the system's ability to perform high-throughput trace contaminant removal. The ultimate goal for this testing was to determine if the unit would be useful in pre-heat exchanger operations to lessen condensed VOCs in recovered water thus lowering the burden of VOC removal for water purification systems.

  19. Bubbling bed catalytic hydropyrolysis process utilizinig larger catalyst particles and small biomass particles featuring an anti-slugging reactor

    Energy Technology Data Exchange (ETDEWEB)

    Marker, Terry L.; Felix, Larry G.; Linck, Martin B.; Roberts, Michael J.

    2016-12-06

    This invention relates to a process for thermochemically transforming biomass or other oxygenated feedstocks into high quality liquid hydrocarbon fuels. In particular, a catalytic hydropyrolysis reactor, containing a deep bed of fluidized catalyst particles is utilized to accept particles of biomass or other oxygenated feedstocks that are significantly smaller than the particles of catalyst in the fluidized bed. The reactor features an insert or other structure disposed within the reactor vessel that inhibits slugging of the bed and thereby minimizes attrition of the catalyst. Within the bed, the biomass feedstock is converted into a vapor-phase product, containing hydrocarbon molecules and other process vapors, and an entrained solid char product, which is separated from the vapor stream after the vapor stream has been exhausted from the top of the reactor. When the product vapor stream is cooled to ambient temperatures, a significant proportion of the hydrocarbons in the product vapor stream can be recovered as a liquid stream of hydrophobic hydrocarbons, with properties consistent with those of gasoline, kerosene, and diesel fuel. Separate streams of gasoline, kerosene, and diesel fuel may also be obtained, either via selective condensation of each type of fuel, or via later distillation of the combined hydrocarbon liquid.

  20. Bubbling bed catalytic hydropyrolysis process utilizing larger catalyst particles and smaller biomass particles featuring an anti-slugging reactor

    Science.gov (United States)

    Marker, Terry L; Felix, Larry G; Linck, Martin B; Roberts, Michael J

    2014-09-23

    This invention relates to a process for thermochemically transforming biomass or other oxygenated feedstocks into high quality liquid hydrocarbon fuels. In particular, a catalytic hydropyrolysis reactor, containing a deep bed of fluidized catalyst particles is utilized to accept particles of biomass or other oxygenated feedstocks that are significantly smaller than the particles of catalyst in the fluidized bed. The reactor features an insert or other structure disposed within the reactor vessel that inhibits slugging of the bed and thereby minimizes attrition of the catalyst. Within the bed, the biomass feedstock is converted into a vapor-phase product, containing hydrocarbon molecules and other process vapors, and an entrained solid char product, which is separated from the vapor stream after the vapor stream has been exhausted from the top of the reactor. When the product vapor stream is cooled to ambient temperatures, a significant proportion of the hydrocarbons in the product vapor stream can be recovered as a liquid stream of hydrophobic hydrocarbons, with properties consistent with those of gasoline, kerosene, and diesel fuel. Separate streams of gasoline, kerosene, and diesel fuel may also be obtained, either via selective condensation of each type of fuel, or via later distillation of the combined hydrocarbon liquid.

  1. Bubbling bed catalytic hydropyrolysis process utilizinig larger catalyst particles and small biomass particles featuring an anti-slugging reactor

    Science.gov (United States)

    Marker, Terry L.; Felix, Larry G.; Linck, Martin B.; Roberts, Michael J.

    2016-12-06

    This invention relates to a process for thermochemically transforming biomass or other oxygenated feedstocks into high quality liquid hydrocarbon fuels. In particular, a catalytic hydropyrolysis reactor, containing a deep bed of fluidized catalyst particles is utilized to accept particles of biomass or other oxygenated feedstocks that are significantly smaller than the particles of catalyst in the fluidized bed. The reactor features an insert or other structure disposed within the reactor vessel that inhibits slugging of the bed and thereby minimizes attrition of the catalyst. Within the bed, the biomass feedstock is converted into a vapor-phase product, containing hydrocarbon molecules and other process vapors, and an entrained solid char product, which is separated from the vapor stream after the vapor stream has been exhausted from the top of the reactor. When the product vapor stream is cooled to ambient temperatures, a significant proportion of the hydrocarbons in the product vapor stream can be recovered as a liquid stream of hydrophobic hydrocarbons, with properties consistent with those of gasoline, kerosene, and diesel fuel. Separate streams of gasoline, kerosene, and diesel fuel may also be obtained, either via selective condensation of each type of fuel, or via later distillation of the combined hydrocarbon liquid.

  2. Novel swirl-flow reactor for kinetic studies of semiconductor photocatalysis

    NARCIS (Netherlands)

    Ray, A.K; Beenackers, A.A C M

    1997-01-01

    A new two-phase swirl-flow monolithic-type reactor was designed to study the kinetics of heterogeneous photocatalytic processes on immobilized semiconductor catalysts. True kinetic rate constants for destruction of a textile dye were measured as a function of wavelength of light intensity and angle

  3. Multi-scale modeling of the heat and mass transfer in a monolithic methane steam-reformer for hydrogen production

    Energy Technology Data Exchange (ETDEWEB)

    Acevedo, Luis Evelio Garcia; Oliveira, Amir Antonio Martins [Universidade Federal de Santa Catarina (UFSC), Florianopolis, SC (Brazil). Dept. de Engenharia Mecanica], e-mail: evelio@labcet.ufsc.br, e-mail: amirol@emc.ufsc.br

    2006-07-01

    Here we present a heat and mass transfer analysis for the catalytic methane steam-reforming in a porous monolithic reactor. Thermodynamic analysis provides the bounds for temperature, pressure and steam-methane molar ration for optimum operation. However, the reactor operation is also constrained by chemical kinetics and heat and mass transfer limitations. Porous wash coated monoliths have been used for a long time in the automotive industry as catalytic converters for destruction of gas and particulate pollutants. Here we analyze the modeling issues related to a multi-scale porous structure and develop a model able to assess the advantages and drawbacks of using a monolith as support for a catalyst layer for steam-reforming. (author)

  4. Effect of catalyst additives on the production of biofuels from palm oil cracking in a transport riser reactor.

    Science.gov (United States)

    Chew, Thiam Leng; Bhatia, Subhash

    2009-05-01

    Catalytic cracking of crude palm oil (CPO) and used palm oil (UPO) were studied in a transport riser reactor for the production of biofuels at a reaction temperature of 450 degrees C, with residence time of 20s and catalyst-to-oil ratio (CTO) of 5 gg(-1). The effect of HZSM-5 (different Si/Al ratios), beta zeolite, SBA-15 and AlSBA-15 were studied as physically mixed additives with cracking catalyst Rare earth-Y (REY). REY catalyst alone gave 75.8 wt% conversion with 34.5 wt% of gasoline fraction yield using CPO, whereas with UPO, the conversion was 70.9 wt% with gasoline fraction yield of 33.0 wt%. HZSM-5, beta zeolite, SBA-15 and AlSBA-15 as additives with REY increased the conversion and the yield of organic liquid product. The transport riser reactor can be used for the continuous production of biofuels from cracking of CPO and UPO over REY catalyst.

  5. Operando UV-Vis spectroscopy of a catalytic solid in a pilos-scale reactor: deactivation of a CrOx/Al2O3 propane dehydrogenation catalyst

    NARCIS (Netherlands)

    Sattler, J.J.H.B.|info:eu-repo/dai/nl/328235601; Gonzalez-Jimenez, I.D.; Mens, A.J.M.|info:eu-repo/dai/nl/313707065; Arias, M.J.|info:eu-repo/dai/nl/314076727; Visser, T.|info:eu-repo/dai/nl/110288327; Weckhuysen, B.M.|info:eu-repo/dai/nl/285484397

    2013-01-01

    A novel operando UV-Vis spectroscopic set-up has been constructed and tested for the investigation of catalyst bodies loaded in a pilot-scale reactor under relevant reaction conditions. Spatiotemporal insight into the formation and burning of coke deposits on an industrial CrOx/Al2O3 catalyst during

  6. Operando UV-Vis spectroscopy of a catalytic solid in a pilos-scale reactor: deactivation of a CrOx/Al2O3 propane dehydrogenation catalyst

    NARCIS (Netherlands)

    Sattler, J.J.H.B.; Gonzalez-Jimenez, I.D.; Mens, A.J.M.; Arias, M.J.; Visser, T.; Weckhuysen, B.M.

    2013-01-01

    A novel operando UV-Vis spectroscopic set-up has been constructed and tested for the investigation of catalyst bodies loaded in a pilot-scale reactor under relevant reaction conditions. Spatiotemporal insight into the formation and burning of coke deposits on an industrial CrOx/Al2O3 catalyst during

  7. Valorization of biogas into liquid hydrocarbons in plasma-catalyst reactor

    Science.gov (United States)

    Nikravech, Mehrdad; Rahmani, Abdelkader; Labidi, Sana; Saintini, Noiric

    2016-09-01

    Biogas represents an important source of renewable energy issued from biological degradation of biomass. It is planned to produce in Europe the amount of biogas equivalent to 6400 kWh electricity and 4500 kteo (kilo tons equivalent oil) in 2020. Currently the biogas is used in cogeneration engines to produce heat and electricity directly in farms or it is injected in gas networks after purification and odorisation. The aim of this work is to propose a third option that consists of valorization of biogas by transformation into liquid hydrocarbons like acetone, methanol, ethanol, acetic acid etc. These chemicals, among the most important feed materials for chemical industries, retain CO2 molecules participating to reduce the greenhouse gas emissions and have high storage energy capacity. We developed a low temperature atmospheric plasma-catalyst reactor (surface dielectric barrier discharge) to transform biogas into chemicals. The conversion rates of CH4 and CO2 are respectively about 50% and 30% depending on operational conditions. The energetic cost is 25 eV/molecule. The yields of liquid hydrocarbon reaches currently 10% wt. More the 11 liquid chemicals are observed in the liquid fraction. Acknowledgements are due to SPC Programme Energie de demain.

  8. Miniaturized catalysis: monolithic, highly porous, large surface area capillary flow reactors constructed in situ from polyhedral oligomeric silsesquioxanes (POSS).

    Science.gov (United States)

    Scholder, P; Nischang, I

    2015-08-21

    A single-step molding process utilizing free-radical cross-linking reaction of vinyl POSS in microliter-sized dimensions leads to hierarchically-structured, mechanically robust, porous hybrid structures. Functional variants show excellent performance in Suzuki-type coupling reactions. Due to their small volume, long-term operational robustness, and potential chemical diversity, these materials are promising candidates for catalyst screening applications.

  9. Oxidative coupling of methane in a fixed bed reactor over perovskite catalyst: A simulation study using experimental kinetic model

    Institute of Scientific and Technical Information of China (English)

    Nakisa Yaghobi; Mir Hamid Reza Ghoreishy

    2008-01-01

    The oxidative coupling of methane (OCM) to ethylene over a perovskite titanate catalyst in a fixed bed reactor was studied experimentally and numerically. The two-dimensional steady state model accounted for separate energy equations for the gas and solid phases coupled with an experimental kinetic model. A lumped kinetic model containing four main species CH4, O2, COx (CO2, CO), and C2 (C2H4 and C2H6) was used with a plug flow reactor model as well. The results from the model agreed with the experimental data. The model was used to analyze the influence of temperature and feed gas composition on the conversion and selectivity of the reactor performance. The analytical results indicate that the conversion decreases, whereas, C2 selectivity increases by increasing gas hourly space velocity (GHSV) and the methane conversion also decreases by increasing the methane to oxygen ratio.

  10. Monoliths: A Review of the Basics, Preparation Methods and Their Relevance to Oxidation

    Directory of Open Access Journals (Sweden)

    Sandeeran Govender

    2017-02-01

    Full Text Available Considerable research has been conducted on monolithic catalysts for various applications. Strategies toward coating monoliths are of equal interest and importance. In this paper, the preparation of monoliths and monolithic catalysts have been summarized. More specifically, a brief explanation for the manufacturing of ceramic and metallic monoliths has been provided. Also, different methods for coating γ-alumina, as a secondary support, are included. Techniques used to deposit metal-based species, zeolites and carbon onto monoliths are discussed. Furthermore, monoliths extruded with metal oxides, zeolites and carbon are described. The main foci are on the reasoning and understanding behind the preparation of monolithic catalysts. Ideas and concerns are also contributed to encourage better approaches when designing these catalysts. More importantly, the relevance of monolithic structures to reactions, such as the selective oxidation of alkanes, catalytic combustion for power generation and the preferential oxidation of carbon monoxide, has been described.

  11. Study on the decomposition of trace benzene over V2O5–WO3/TiO2-based catalysts in simulated flue gas

    Science.gov (United States)

    Trace levels (1 and 10 ppm) of gaseous benzene were catalytically decomposed in a fixed-bed catalytic reactor with monolithic oxides of vanadium and tungsten supported on titanium oxide (V2O5–WO3/TiO2) catalysts under conditions simulating the cooling of waste incineration flue g...

  12. Deactivation of V2O5-WO3-TiO2 SCR catalyst at a biomass-fired combined heat and power plant

    DEFF Research Database (Denmark)

    Zheng, Yuanjing; Jensen, Anker; Johnsson, Jan Erik

    2005-01-01

    The deactivation of a commercial type V2O5-WO3-TiO2 monolith catalyst under biomass combustion was studied at a full-scale grate-fired power plant burning straw/wood using a slip stream pilot scale reactor. The aerosols in the flue gas consisted of a mixture of potassium chloride and sulphate. Th...

  13. Towards automation in protein digestion: Development of a monolithic trypsin immobilized reactor for highly efficient on-line digestion and analysis.

    Science.gov (United States)

    Naldi, Marina; Černigoj, Urh; Štrancar, Ales; Bartolini, Manuela

    2017-05-15

    Reducing experimental variability, limiting contamination and increasing automation are essential goals in the development of reliable analytical platforms for mass spectrometry (MS)-based proteomics. In this work novel trypsin-based monolithic immobilized enzyme reactors (tryp-IMERs), obtained by covalent immobilization on convective interaction media (CIMac™) analytical columns (5mm×5.2mm I.D.), were developed. Notwithstanding the small dimensions, column format allowed the insertion in common high performance liquid chromatography (HPLC) systems, thus avoiding the use of expensive micro- or nano-platforms. Monolith pore diameter and surface chemistry were optimized to achieve high digestion efficiency even with high molecular weight proteins and to avoid protein/peptide adsorption, peak broadening and sample loss. A full characterization of the tryp-IMERs was undertaken to select the best protocol for preparation and type of trypsin. Optimization of the operational and storage conditions was carried out by an off-line approach. On-line studies were performed by setting a multidimensional analytical platform, which included the tryp-IMER, a trapping column, an analytical C4 column and a high resolution hybrid mass spectrometer (ESI-Q-TOF). In the optimized conditions rapid protein digestion (90±9s), high protein coverage (≥60%) and high score values were achieved for five selected sample proteins (cytochrome c, myoglobin and albumins from different sources) differing in molecular size, isoelectric point and accessibility to cleavage sites as well as for a protein mixture of 200ng. The best performing tryp-IMERs showed high sensitivity down to the pmole level. The platform also resulted suitable for the analysis of high-molecular weight proteins such as a pool of human immunoglobulins G (hIgG) and for the high molecular weight fraction of human plasma proteins, which were digested in less than two minutes to an extent similar to that achieved by overnight

  14. Monolithic spectrometer

    Science.gov (United States)

    Rajic, Slobodan; Egert, Charles M.; Kahl, William K.; Snyder, Jr., William B.; Evans, III, Boyd M.; Marlar, Troy A.; Cunningham, Joseph P.

    1998-01-01

    A monolithic spectrometer is disclosed for use in spectroscopy. The spectrometer is a single body of translucent material with positioned surfaces for the transmission, reflection and spectral analysis of light rays.

  15. Autothermal Reforming and Partial Oxidation of Methane in Fluidized Reactor over Highly Dispersed Ni Catalyst Prepared from Ni Complex

    Institute of Scientific and Technical Information of China (English)

    GAO Jing; HOU Zhao-Yin; SHEN Kai; LOU Hui; FEI Jin-Hua; ZHENG Xiao-Ming

    2006-01-01

    Highly dispersed Ni catalysts on spherical SiO2 were prepared by simple impregnation of Ni(acac)2, [Ni-(NH3)6-n(H2O)n]2+, [Ni(en)3]2+ and [Ni(EDTA)]2-. Pulse adsorption of H2 and TEM analysis results confirmed that Ni was dispersed very well on the surface of SiO2 even after calcination (4 h) and reduction (1 h) at high temperature of 800 ℃. These highly dispersed and uniquely sized Ni crystallites were more stable and more reactive for both autothermal reforming and partial oxidation of methane in fluidized reactor.

  16. Pd-Ag Membrane Coupled to a Two-Zone Fluidized Bed Reactor (TZFBR) for Propane Dehydrogenation on a Pt-Sn/MgAl2O4 Catalyst.

    Science.gov (United States)

    Medrano, José-Antonio; Julián, Ignacio; Herguido, Javier; Menéndez, Miguel

    2013-05-14

    Several reactor configurations have been tested for catalytic propane dehydrogenation employing Pt-Sn/MgAl2O4 as a catalyst. Pd-Ag alloy membranes coupled to the multifunctional Two-Zone Fluidized Bed Reactor (TZFBR) provide an improvement in propane conversion by hydrogen removal from the reaction bed through the inorganic membrane in addition to in situ catalyst regeneration. Twofold process intensification is thereby achieved when compared to the use of traditional fluidized bed reactors (FBR), where coke formation and thermodynamic equilibrium represent important process limitations. Experiments were carried out at 500-575 °C and with catalyst mass to molar flow of fed propane ratios between 15.1 and 35.2 g min mmol-1, employing three different reactor configurations: FBR, TZFBR and TZFBR + Membrane (TZFBR + MB). The results in the FBR showed catalyst deactivation, which was faster at high temperatures. In contrast, by employing the TZFBR with the optimum regenerative agent flow (diluted oxygen), the process activity was sustained throughout the time on stream. The TZFBR + MB showed promising results in catalytic propane dehydrogenation, displacing the reaction towards higher propylene production and giving the best results among the different reactor configurations studied. Furthermore, the results obtained in this study were better than those reported on conventional reactors.

  17. Pd-Ag Membrane Coupled to a Two-Zone Fluidized Bed Reactor (TZFBR for Propane Dehydrogenation on a Pt-Sn/MgAl2O4 Catalyst

    Directory of Open Access Journals (Sweden)

    Miguel Menéndez

    2013-05-01

    Full Text Available Several reactor configurations have been tested for catalytic propane dehydrogenation employing Pt-Sn/MgAl2O4 as a catalyst. Pd-Ag alloy membranes coupled to the multifunctional Two-Zone Fluidized Bed Reactor (TZFBR provide an improvement in propane conversion by hydrogen removal from the reaction bed through the inorganic membrane in addition to in situ catalyst regeneration. Twofold process intensification is thereby achieved when compared to the use of traditional fluidized bed reactors (FBR, where coke formation and thermodynamic equilibrium represent important process limitations. Experiments were carried out at 500–575 °C and with catalyst mass to molar flow of fed propane ratios between 15.1 and 35.2 g min mmol−1, employing three different reactor configurations: FBR, TZFBR and TZFBR + Membrane (TZFBR + MB. The results in the FBR showed catalyst deactivation, which was faster at high temperatures. In contrast, by employing the TZFBR with the optimum regenerative agent flow (diluted oxygen, the process activity was sustained throughout the time on stream. The TZFBR + MB showed promising results in catalytic propane dehydrogenation, displacing the reaction towards higher propylene production and giving the best results among the different reactor configurations studied. Furthermore, the results obtained in this study were better than those reported on conventional reactors.

  18. Influence of V2O5 Addition on Reduction of NO by C3H6 over Pt/V2O5/Al2O3 Monolithic Catalyst

    Institute of Scientific and Technical Information of China (English)

    Kang Shoufang; Jiang Zheng; Yu Junjie; Hao Zhengping

    2004-01-01

    Pt/V2O5/Al2O3 and Pt/Al2O3 monolithic catalysts were prepared by wet impregnation method, and the influence of V2 O5 addition on the catalytic activity for NO reduction by C3 H6 under lean burn condition was investigated in detail.The results show that Pt/V2O5/Al2O3 has better activity of NO reduction than Pt/Al2O3 , adding V2O5 to Pt catalyst makes the temperature window of NO reduction shift further to a lower temperature region.The activity of NO reduction decreases and there is a similar degree of deactivation over the two catalysts in the presence of SO2 in feed gas.Moreover, adding V2 O5 to Pt catalyst resulted in improvement of resistance to SO2 oxidation, which decreases the emission of sulfate particulate.Thermal aging treatment counteractes the promoting effect of V2O5 on NO reduction.

  19. Mathematical Modelling of Catalytic Fixed-Bed Reactor for Carbon Dioxide Reforming of Methane over Rh/Al2O3 Catalyst

    Directory of Open Access Journals (Sweden)

    Nor Aishah Saidina Amin

    2010-10-01

    Full Text Available A one-dimensional mathematical model was developed to simulate the performance of catalytic fixed bed reactor for carbon dioxide reforming of methane over Rh/Al2O3 catalyst at atmospheric pressure. The reactions involved in the system are carbon dioxide reforming of methane (CORM and reverse water gas shift reaction (RWGS. The profiles of CH4 and CO2 conversions, CO and H2 yields, molar flow rate and mole raction of all species as well as reactor temperature along the axial bed of catalyst were simulated. In addition, the effects of different reactor temperature on the reactor performance were also studied. The models can also be applied to analyze the performances of lab-scale micro reactor as well as pilot-plant scale reactor with certain modifications and model verification with experimental data. © 2008 BCREC UNDIP. All rights reserved.[Received: 20 August 2008; Accepted: 25 September 2008][How to Cite: N.A.S. Amin, I. Istadi, N.P. Yee. (2008. Mathematical Modelling of Catalytic Fixed-Bed Reactor for Carbon Dioxide Reforming of Methane over Rh/Al2O3 Catalyst. Bulletin of Chemical Reaction Engineering and Catalysis, 3 (1-3: 21-29.  doi:10.9767/bcrec.3.1-3.7120.21-29][How to Link/DOI: http://dx.doi.org/10.9767/bcrec.3.1-3.7120.21-29 || or local: http://ejournal.undip.ac.id/index.php/bcrec/article/view/7120

  20. Effect of diluent and reaction parameter on selective oxidation of propane over MoVTeNb catalyst using nanoflow catalytic reactor

    Institute of Scientific and Technical Information of China (English)

    Restu Kartiko Widi; Sharifah Bee Abdul Hamid; Robert Schl(o)gl

    2008-01-01

    The selective oxidation of propane to acrylic acid over an MoVTeNb mixed oxide catalyst, dried and calcined before reaction has been studied using high-throughput instrumentation, which is called nanoflow catalytic reactor. The effects of catalyst dilution on the catalytic performance of the MoVTeNb mixed oxide catalyst in selective oxidation of propane to acrylic acid were also investigated. The effects of some reaction parameters, such as gas hourly space velocity (GHSV) and reaction temperature, for selective oxidation of propane to acrylic acid over diluted MoVTeNb catalyst have also been studied. The configuration of the nanoflow is shown to be suitable for screen catalytic performance, and its operating conditions were mimicked closely to conventional laboratory as well as to industrial conditions. The results obtained provided very good reproducibility and it showed that preparation methods as well as reaction parameters can play significant roles in catalytic performance of these catalysts.

  1. Comparision of real waste (MSW and MPW) pyrolysis in batch reactor over different catalysts. Part I: product yields, gas and pyrolysis oil properties.

    Science.gov (United States)

    Ateş, Funda; Miskolczi, Norbert; Borsodi, Nikolett

    2013-04-01

    Pyrolysis of municipal solid waste (MSW) and municipal plastic waste (MPW) have been investigated in batch reactor at 500, 550 and 600°C both in absence and presence of catalysts (Y-zeolite, β-zeolite, equilibrium FCC, MoO3, Ni-Mo-catalyst, HZSM-5 and Al(OH)3). The effect of the parameters on the product properties was investigated. Products were characterized using gas-chromatography, GC/MS, (13)C NMR. Yields of volatile fractions increased, while reaction time necessity for the total cracking decreased in the presence of catalysts. Catalysts have productivity and selectivity in converting aliphatic hydrocarbons to aromatic and cyclic compounds in oil products. Gases from MSW consisted of hydrogen CO, CO2, while exclusively hydrogen and hydrocarbons were detected from MPW. Catalyst efficiency was higher using MPW than MSW. Pyrolysis oils contained aliphatic hydrocarbons, aromatics, cyclic compounds and less ketones, alcohols, acids or esters depending on the raw materials.

  2. 镍基整体式催化剂重整净化生物制粗燃气性能的研究%Reforming of Biomass Raw Fuel Gas over Monolithic Catalyst

    Institute of Scientific and Technical Information of China (English)

    王晨光; 王铁军; 常杰; 吕鹏梅

    2007-01-01

    The performance of the Ni monolithic catalyst for dry reforming and partial oxidation reforming(POR) of biomass fuel gas were studied at 750 ℃ during 108 hours with naphthalene as tar model compound. The catalyst shows good performance in both dry reforming and POR. Tar was completely converted to permanent gases and lighter hydrocarbon compounds. The catalyst kept its activity during the lifetime test.%以萘为焦油模型化合物,考察了镍基整体式催化剂上生物质粗燃气干重整和临氧重整的性能.镍基重整催化剂表现出良好的催化重整活性,焦油全部转化为H2、CO及微量轻质组分.在750 ℃下连续反应108 h,未检测到反应器压降变化和CH4与焦油转化率下降,整体式催化剂表现出较好的活性和稳定性.

  3. TiO{sub 2} on magnesium silicate monolith: effects of different preparation techniques on the photocatalytic oxidation of chlorinated hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Cardona, Ana I.; Candal, Roberto; Sanchez, Benigno; Avila, Pedro; Rebollar, Moises

    2004-05-01

    In this article, the comparative results of the photocatalytic oxidation of trichloroethylene (TCE) alone and a mixture of chlorinated hydrocarbons (trichloroethylene, perchloroethylene and chloroform) in gas phase, obtained with three different monolithic catalysts in a flat reactor frontally illuminated with a Xenon lamp are presented. The three catalysts incorporate titanium dioxide (TiO{sub 2}) as active phase on a magnesium silicate support, by means of different procedures: (i) incorporation of commercial TiO{sub 2} powder into the silicate matrix ('massic monolith'); (ii) sol-gel coating of the silicate support; (iii) impregnation with a commercial TiO{sub 2} aqueous suspension of the same silicate support. In the first case, the massic monolith was made from a 50:50 w/w mixture of magnesium silicate and 'Titafrance G5' TiO{sub 2} powder. In the second case, a magnesium silicate monolith was coated with several layers of an aqueous TiO{sub 2} sol prepared from hydrolysis and condensation of titanium tetra-isopropoxide (Ti(OC{sub 3}H{sub 7}){sub 4}) in excess of acidified water (acid catalysis). The third catalyst was prepared by impregnating the same silicate support with several layers of 'Titafrance G5' TiO{sub 2} powder water suspension. All the catalysts were thermal treated under comparable conditions in order to fix the TiO{sub 2} active phase to the silicate support. Although the performance of the massic monolith was better than the sol-gel monolith, the latter is of great interest because this technique allows the chemical composition of the active films to be easily modified.

  4. Real-Time Quantitative Operando Raman Spectroscopy of a CrOx/Al2O3 Propane Dehydrogenation Catalyst in a Pilot-Scale Reactor

    NARCIS (Netherlands)

    Sattler, Jesper J. H. B.|info:eu-repo/dai/nl/328235601; Mens, Ad M.; Weckhuysen, Bert M.|info:eu-repo/dai/nl/285484397

    2014-01-01

    Combined operando UV/vis-Raman spectroscopy has been used to study the deactivation of CrOx/Al2O3 catalyst extrudates in a pilot scale propane dehydrogenation reactor. For this purpose, UV/vis and Raman optical fiber probes have been designed, constructed and tested. The light absorption measured by

  5. Catalyst Residence Time Distributions in Riser Reactors for Catalytic Fast Pyrolysis. Part 2: Pilot-Scale Simulations and Operational Parameter Study

    Energy Technology Data Exchange (ETDEWEB)

    Foust, Thomas D.; Ziegler, Jack L.; Pannala, Sreekanth; Ciesielski, Peter; Nimlos, Mark R.; Robichaud, David J.

    2017-02-21

    Using the validated simulation model developed in part one of this study for biomass catalytic fast pyrolysis (CFP), we assess the functional utility of using this validated model to assist in the development of CFP processes in fluidized catalytic cracking (FCC) reactors to a commercially viable state. Specifically, we examine the effects of mass flow rates, boundary conditions (BCs), pyrolysis vapor molecular weight variation, and the impact of the chemical cracking kinetics on the catalyst residence times. The factors that had the largest impact on the catalyst residence time included the feed stock molecular weight and the degree of chemical cracking as controlled by the catalyst activity. Because FCC reactors have primarily been developed and utilized for petroleum cracking, we perform a comparison analysis of CFP with petroleum and show the operating regimes are fundamentally different.

  6. Mathematical Modelling of Catalytic Fixed-Bed Reactor for Carbon Dioxide Reforming of Methane over Rh/Al2O3 Catalyst

    Directory of Open Access Journals (Sweden)

    New Pei Yee

    2008-04-01

    Full Text Available A one-dimensional mathematical model was developed to simulate the performance of catalytic fixed bedreactor for carbon dioxide reforming of methane over Rh/Al2O3 catalyst at atmospheric pressure. The reactionsinvolved in the system are carbon dioxide reforming of methane (CORM and reverse water gas shiftreaction (RWGS. The profiles of CH4 and CO2 conversions, CO and H2 yields, molar flow rate and molefraction of all species as well as reactor temperature along the axial bed of catalyst were simulated. In addition,the effects of different reactor temperature on the reactor performance were also studied. The modelscan also be applied to analyze the performances of lab-scale micro reactor as well as pilot-plant scale reactorwith certain modifications and model verification with experimental data. © 2008 BCREC UNDIP. All rights reserved.[Received: 20 August 2008; Accepted: 25 September 2008][How to Cite: N.A.S. Amin, I. Istadi, N.P. Yee. (2008. Mathematical Modelling of Catalytic Fixed-Bed Reactor for Carbon Dioxide Reforming of Methane over Rh/Al2O3 Catalyst. Bulletin of Chemical Reaction Engineering and Catalysis, 3 (1-3: 21-29. doi:10.9767/bcrec.3.1-3.19.21-29

  7. Simultaneous Oxidization of NOx and 802 by a New Non-thermal Plasma Reactor Enhanced by Catalyst and Additive

    Institute of Scientific and Technical Information of China (English)

    Heejoon KIM; HAN Jun; Yuhei SAKAGUCHI; Wataru MINAMI

    2008-01-01

    The non-thermal plasma as one of the most promising technologies for removing NOx and SO2 has attracted much attention. In this study, a new plasma reactor combined with catalyst and additive was developed to effectively oxidize and remove NOx and SO2 in the flue gas. The experimental results showed that TiO2 could improve the oxidation efficiency of SO2 in the case of applying plasma while having a negative effect on the oxidation process of NO and NOx. With the addition of NH3, the oxidation rates of NOx, NO and SO2 were slightly increased. However, the effect of adding NH3 on NOx oxidation was negative when the temperature was above 200℃.

  8. Dual Layer Monolith ATR of Pyrolysis Oil for Distributed Synthesis Gas Production

    Energy Technology Data Exchange (ETDEWEB)

    Lawal, Adeniyi [Stevens Institute of Technology, Castle Point Hoboken NJ 07030

    2012-09-29

    We have successfully demonstrated a novel reactor technology, based on BASF dual layer monolith catalyst, for miniaturizing the autothermal reforming of pyrolysis oil to syngas, the second and most critical of the three steps for thermochemically converting biomass waste to liquid transportation fuel. The technology was applied to aged as well as fresh samples of pyrolysis oil derived from five different biomass feedstocks, namely switch-grass, sawdust, hardwood/softwood, golden rod and maple. Optimization of process conditions in conjunction with innovative reactor system design enabled the minimization of carbon deposit and control of the H2/CO ratio of the product gas. A comprehensive techno-economic analysis of the integrated process using in part, experimental data from the project, indicates (1) net energy recovery of 49% accounting for all losses and external energy input, (2) weight of diesel oil produced as a percent of the biomass to be ~14%, and (3) for a demonstration size biomass to Fischer-Tropsch liquid plant of ~ 2000 daily barrels of diesel, the price of the diesel produced is ~$3.30 per gallon, ex. tax. However, the extension of catalyst life is critical to the realization of the projected economics. Catalyst deactivation was observed and the modes of deactivation, both reversible and irreversible were identified. An effective catalyst regeneration strategy was successfully demonstrated for reversible catalyst deactivation while a catalyst preservation strategy was proposed for preventing irreversible catalyst deactivation. Future work should therefore be focused on extending the catalyst life, and a successful demonstration of an extended (> 500 on-stream hours) catalyst life would affirm the commercial viability of the process.

  9. Catalyst-coated cement beads for the degradation and mineralization of fungicide carbendazim using laboratory and pilot-scale reactor: catalyst stability analysis.

    Science.gov (United States)

    Singh, Amanjit; Verma, Anoop; Bansal, Palak; Aggarwal, Kashish; Kaur, Taranjeet; Toor, Amrit Pal; Sangal, Vikas Kumar

    2017-03-18

    The fixed-bed photocatalytic degradation of fungicide carbendazim using catalyst-coated spherical cement beads has been investigated. Thirty beads with optimum size 13 mm along with 0.3 gL(-1) H2O2 with an initial concentration of carbendazim of 10 mgL(-1) were the optimized conditions for better degradation. The reduction in COD and total organic carbon along with the generation of nitrite and nitrate ions under the optimized conditions confirms the complete mineralization of compound. The suggested degradation pathway for carbendazim has also been proposed as intermediates formed during photodegradation were analyzed through gas chromatography-mass spectrometry. The coated cement beads were found to be durable even after 30 cycles as confirmed by scanning electron microscopy and energy dispersive spectroscopy analysis. Scale-up trails have also been carried out in a solar-baffled fixed-bed reactor for the degradation of pollutant to seek the commercial viability of the technique.

  10. Deactivation by carbon of iron catalysts for indirect liquefaction

    Energy Technology Data Exchange (ETDEWEB)

    Bartholomew, C.H.

    1991-01-10

    Although promoted cobalt and iron catalysts for Fischer-Tropsch (FT) synthesis of gasoline feedstock were first developed more than three decades ago, a major technical problem still limiting the commercial use of these catalysts today is carbon deactivation. This report describes recent progress in a fundamental, three-year investigation of carbon formation and its effects on the activity and selectivity of promoted iron catalysts for FT synthesis, the objectives of which are to: determine rates and mechanisms of carbon deactivation of unsupported Fe and Fe/K catalysts during CO hydrogenation over a range of CO concentrations, CO:H{sub 2} ratios, and temperatures; and model the rates of deactivation of the same catalysts in fixed-bed reactors. To accomplish the above objectives, the project is divided into the following tasks: (1) determine the kinetics of reaction and of carbon deactivation during CO hydrogenation on Fe and Fe/K catalysts coated on monolith bodies. (2) Determine the reactivities and types of carbon deposited during reaction on the same catalysts from temperature-programmed-surface-reaction spectroscopy (TPSR) and transmission electron microscopy (TEM). Determine the types of iron carbides formed at various temperatures and H{sub 2}/CO ratios using x-ray diffraction and Moessbauer spectroscopy. (3) Develop mathematical deactivation models which include heat and mass transport contributions for FT synthesis is packed-bed reactors. Progress to date is described. 48 refs., 3 figs., 1 tab.

  11. Hydrogen-Permeable Tubular Membrane Reactor: Promoting Conversion and Product Selectivity for Non-Oxidative Activation of Methane over an Fe©SiO2 Catalyst.

    Science.gov (United States)

    Sakbodin, Mann; Wu, Yiqing; Oh, Su Cheun; Wachsman, Eric D; Liu, Dongxia

    2016-12-23

    Non-oxidative methane conversion over Fe©SiO2 catalyst was studied for the first time in a hydrogen (H2 ) permeable tubular membrane reactor. The membrane reactor is composed of a mixed ionic-electronic SrCe0.7 Zr0.2 Eu0.1 O3-δ thin film (≈20 μm) supported on the outer surface of a one-end capped porous SrCe0.8 Zr0.2 O3-δ tube. Significant improvement in CH4 conversion was achieved upon H2 removal from the membrane reactor compared to that in a fixed-bed reactor. The Fe©SiO2 catalyst in the H2 permeable membrane reactor demonstrated a stable ≈30 % C2+ single-pass yield, with up to 30 % CH4 conversion and 99 % selectivity to C2 (ethylene and acetylene) and aromatic (benzene and naphthalene) products, at the tested conditions. The selectivity towards C2 or aromatics was manipulated purposely by adding H2 into or removing H2 from the membrane reactor feed and permeate gas streams. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Catalysts with Cerium in a Membrane Reactor for the Removal of Formaldehyde Pollutant from Water Effluents

    OpenAIRE

    2016-01-01

    We report the synthesis of cerium oxide, cobalt oxide, mixed cerium, and cobalt oxides and a Ce–Co/Al2O3 membrane, which are employed as catalysts for the catalytic wet oxidation (CWO) reaction process and the removal of formaldehyde from industrial effluents. Formaldehyde is present in numerous waste streams from the chemical industry in a concentration low enough to make its recovery not economically justified but high enough to create an environmental hazard. Common biological degradation ...

  13. Ethane dehydrogenation over nano-Cr 2O 3 anode catalyst in proton ceramic fuel cell reactors to co-produce ethylene and electricity

    Science.gov (United States)

    Fu, Xian-Zhu; Luo, Xiao-Xiong; Luo, Jing-Li; Chuang, Karl T.; Sanger, Alan R.; Krzywicki, Andrzej

    Ethane and electrical power are co-generated in proton ceramic fuel cell reactors having Cr 2O 3 nanoparticles as anode catalyst, BaCe 0.8Y 0.15Nd 0.05O 3- δ (BCYN) perovskite oxide as proton conducting ceramic electrolyte, and Pt as cathode catalyst. Cr 2O 3 nanoparticles are synthesized by a combustion method. BaCe 0.8Y 0.15Nd 0.05O 3- δ (BCYN) perovskite oxides are obtained using a solid state reaction. The power density increases from 51 mW cm -2 to 118 mW cm -2 and the ethylene yield increases from about 8% to 31% when the operating temperature of the solid oxide fuel cell reactor increases from 650 °C to 750 °C. The fuel cell reactor and process are stable at 700 °C for at least 48 h. Cr 2O 3 anode catalyst exhibits much better coke resistance than Pt and Ni catalysts in ethane fuel atmosphere at 700 °C.

  14. Reducing-Agent-Free Instant Synthesis of Carbon-Supported Pd Catalysts in a Green Leidenfrost Droplet Reactor and Catalytic Activity in Formic Acid Dehydrogenation.

    Science.gov (United States)

    Lee, Dong-Wook; Jin, Min-Ho; Lee, Young-Joo; Park, Ju-Hyoung; Lee, Chun-Boo; Park, Jong-Soo

    2016-05-20

    The development of green synthesis methods for supported noble metal catalysts remains important challenges to improve their sustainability. Here we first synthesized carbon-supported Pd catalysts in a green Leidenfrost droplet reactor without reducing agents, high-temperature calcination and reduction procedures. When the aqueous solution containing Pd nitrate precursor, carbon support, and water is dripped on a hot plate, vapor layer is formed between a solution droplet and hot surface, which allow the solution droplet to be levitated on the hot surface (Leidenfrost phenomena). Subsequently, Pd nanoparticles can be prepared without reducing agents in a weakly basic droplet reactor created by the Leidenfrost phenomena, and then the as-prepared Pd nanoparticles are loaded on carbon supports during boiling down the droplet on hot surface. Compared to conventional incipient wetness and chemical synthetic methods, the Leidenfrost droplet reactor does not need energy-consuming, time-consuming, and environmentally unfriendly procedures, which leads to much shorter synthesis time, lower carbon dioxide emission, and more ecofriendly process in comparison with conventional synthesis methods. Moreover, the catalysts synthesized in the Leidenfrost droplet reactor provided much better catalytic activity for room-temperature formic acid decomposition than those prepared by the incipient wetness method.

  15. Reducing-Agent-Free Instant Synthesis of Carbon-Supported Pd Catalysts in a Green Leidenfrost Droplet Reactor and Catalytic Activity in Formic Acid Dehydrogenation

    Science.gov (United States)

    Lee, Dong-Wook; Jin, Min-Ho; Lee, Young-Joo; Park, Ju-Hyoung; Lee, Chun-Boo; Park, Jong-Soo

    2016-05-01

    The development of green synthesis methods for supported noble metal catalysts remains important challenges to improve their sustainability. Here we first synthesized carbon-supported Pd catalysts in a green Leidenfrost droplet reactor without reducing agents, high-temperature calcination and reduction procedures. When the aqueous solution containing Pd nitrate precursor, carbon support, and water is dripped on a hot plate, vapor layer is formed between a solution droplet and hot surface, which allow the solution droplet to be levitated on the hot surface (Leidenfrost phenomena). Subsequently, Pd nanoparticles can be prepared without reducing agents in a weakly basic droplet reactor created by the Leidenfrost phenomena, and then the as-prepared Pd nanoparticles are loaded on carbon supports during boiling down the droplet on hot surface. Compared to conventional incipient wetness and chemical synthetic methods, the Leidenfrost droplet reactor does not need energy-consuming, time-consuming, and environmentally unfriendly procedures, which leads to much shorter synthesis time, lower carbon dioxide emission, and more ecofriendly process in comparison with conventional synthesis methods. Moreover, the catalysts synthesized in the Leidenfrost droplet reactor provided much better catalytic activity for room-temperature formic acid decomposition than those prepared by the incipient wetness method.

  16. Mechanically stable, hierarchically porous Cu3(btc)2 (HKUST-1) monoliths via direct conversion of copper(II) hydroxide-based monoliths.

    Science.gov (United States)

    Moitra, Nirmalya; Fukumoto, Shotaro; Reboul, Julien; Sumida, Kenji; Zhu, Yang; Nakanishi, Kazuki; Furukawa, Shuhei; Kitagawa, Susumu; Kanamori, Kazuyoshi

    2015-02-28

    The synthesis of highly crystalline macro-meso-microporous monolithic Cu3(btc)2 (HKUST-1; btc(3-) = benzene-1,3,5-tricarboxylate) is demonstrated by direct conversion of Cu(OH)2-based monoliths while preserving the characteristic macroporous structure. The high mechanical strength of the monoliths is promising for possible applications to continuous flow reactors.

  17. Aspects of stability of K/Al2O3 catalysts for the transesterification of rapeseed oil in batch and fixed-bed reactors

    Institute of Scientific and Technical Information of China (English)

    Petr Kutálek; Libor Čapek; Lucie Smoláková; David Kubička; Martin Hájek

    2014-01-01

    Catalytically active, stable, and mechanically durable solid K/Al2O3 catalysts for the transesterifica-tion of rapeseed oil with methanol was studied. In a batch reactor, high catalytic activity was ac-companied by leaching of K species, caused by glycerol, and mechanical destruction of the solid catalyst as a result of contact with the stirrer. In a fixed-bed reactor, some leaching of K species into the liquid phases was also observed, but approached 0 during 30 h of time-on-stream; the activity of the K/Al2O3 catalyst (~83% ester yield) was stable for 100 h of time-on-stream and no mechanical destruction of the catalyst was observed. The populations of K2O and K-O-Al species for fresh and used K/Al2O3 catalysts were compared using Fourier transform infrared spectroscopy. It was found that some K2O species leached into the liquid phases at the beginning of the reaction.

  18. Creation of Pd/Al2O3 Catalyst by a Spray Process for Fixed Bed Reactors and Its Effective Removal of Aqueous Bromate

    Science.gov (United States)

    Gao, Yu; Sun, Wuzhu; Yang, Weiyi; Li, Qi

    2017-02-01

    Palladium nanoparticles were grown on sub-millimeter activated Al2O3 particle support by spraying H2PdCl4 solution evenly onto the support, followed with a thermal reduction under H2 atmosphere. Compared with its counterpart created by the conventional impregnation method, the Pd/Al2O3 catalyst created by the spray process could enrich the existence of active Pd nanoparticles on the surface of the catalyst support and increase their degree of dispersion, resulting in a much higher activity in the catalytic reduction of bromate in water. The effect of Al2O3 support particle size on the bromate removal rate was also investigated, which demonstrated that smaller support particle size could have higher activity in the catalytic reduction of bromate in water because of its larger exposed surface. This Pd/Al2O3 catalyst could be easily used in the fixed bed reactor due to its large support size and demonstrated excellent stability in the catalytic reduction of bromate in mineral water. This Pd/Al2O3 catalyst also exhibited a good catalytic reduction performance on azo dyes as demonstrated by its effective catalytic hydrogenation of methyl orange. Thus, catalysts prepared by the spray method developed in this work could have the potential to be used in fixed bed reactors for various water treatment practices.

  19. Novel micro-reactor flow cell for investigation of model catalysts using in situ grazing-incidence X-ray scattering

    DEFF Research Database (Denmark)

    Kehres, Jan; Pedersen, Thomas; Masini, Federico

    2016-01-01

    -incidence small-angle X-ray scattering (GISAXS) in transmission through 10 µm-thick entrance and exit windows by using micro-focused beams. An additional thinning of the Pyrex glass reactor lid allows simultaneous acquisition of the grazing-incidence wide-angle X-ray scattering (GIWAXS). In situ experiments......The design, fabrication and performance of a novel and highly sensitive micro-reactor device for performing in situ grazing-incidence X-ray scattering experiments of model catalyst systems is presented. The design of the reaction chamber, etched in silicon on insulator (SIO), permits grazing...... at synchrotron facilities are performed utilizing the micro-reactor and a designed transportable gas feed and analysis system. The feasibility of simultaneous in situ GISAXS/GIWAXS experiments in the novel micro-reactor flow cell was confirmed with CO oxidation over mass-selected Ru nanoparticles....

  20. Development of a reactor with carbon catalysts for modular-scale, low-cost electrochemical generation of H 2 O 2

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Zhihua; Chen, Shucheng; Siahrostami, Samira; Chakthranont, Pongkarn; Hahn, Christopher; Nordlund, Dennis; Dimosthenis, Sokaras; Nørskov, Jens K.; Bao, Zhenan; Jaramillo, Thomas F.

    2017-03-01

    The development of small-scale, decentralized reactors for H2O2 production that can couple to renewable energy sources would be of great benefit, particularly for water purification in the developing world. Herein, we describe our efforts to develop electrochemical reactors for H2O2 generation with high Faradaic efficiencies of >90%, requiring cell voltages of only ~1.6 V. The reactor employs a carbon-based catalyst that demonstrates excellent performance for H2O2 production under alkaline conditions, as demonstrated by fundamental studies involving rotating-ring disk electrode methods. The low-cost, membrane-free reactor design represents a step towards a continuous, modular-scale, de-centralized production of H2O2.

  1. Effects of reaction conditions on hydrogen production and carbon nanofiber properties generated by methane decomposition in a fixed bed reactor using a NiCuAl catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Suelves, I.; Pinilla, J.L.; Lazaro, M.J.; Moliner, R. [Instituto de Carboquimica CSIC, Miguel Luesma Castan, 4, 50015 Zaragoza (Spain); Palacios, J.M. [Instituto de Catalisis y Petroleoquimica, CSIC, Cantoblanco, Marie Curie 2, 28049 Madrid (Spain)

    2009-07-01

    In this paper, the results obtained in the catalytic decomposition of methane in a fixed bed reactor using a NiCuAl catalyst prepared by the fusion method are presented. The influences of reaction temperature and space velocity on hydrogen concentration in the outlet gases, as well as on the properties of the carbon produced, have been investigated. Reaction temperature and the space velocity both increase the reaction rate of methane decomposition, but also cause an increase in the rate of catalyst deactivation. Under the operating conditions used, the carbon product is mainly deposited as nanofibers with textural properties highly correlated with the degree of crystallinity. (author)

  2. Monolithic Fuel Fabrication Process Development

    Energy Technology Data Exchange (ETDEWEB)

    C. R. Clark; N. P. Hallinan; J. F. Jue; D. D. Keiser; J. M. Wight

    2006-05-01

    The pursuit of a high uranium density research reactor fuel plate has led to monolithic fuel, which possesses the greatest possible uranium density in the fuel region. Process developments in fabrication development include friction stir welding tool geometry and cooling improvements and a reduction in the length of time required to complete the transient liquid phase bonding process. Annealing effects on the microstructures of the U-10Mo foil and friction stir welded aluminum 6061 cladding are also examined.

  3. Catalytic Wet Air Oxidation of Oxalic Acid using Platinum Catalysts in Bubble Column Reactor: A Review

    Directory of Open Access Journals (Sweden)

    A. K. Saroha

    2010-01-01

    Full Text Available Wastewater treatment and re-use of industrial process water are critical issue for the development of human activities andenvironment conservation. Catalytic wet air oxidation (CWAO is an attractive and useful technique for treatment of effluentswhere the concentrations of organic pollutants are too low, for the incineration and other pollution control techniquesto be economically feasible and when biological treatments are ineffective, e.g. in the case of toxic effluents. In CWAO,combustion takes place on a Pt/Al2O3 catalysts usually at temperatures several degrees below those required forthermal incineration. In CWAO process, the organic contaminants dissolved in water are either partially degraded by meansof an oxidizing agent into biodegradable intermediates or mineralized into innocuous inorganic compounds such as CO2,H2O and inorganic salts, which remain in the aqueous phase. In contrast to other thermal processes CWAO produces no NOx,SO2, HCl, dioxins, furans, fly ash, etc. This review paper presents the application of platinum catalysts in bubble columnreactor for CWAO of oxalic acid.

  4. Glycerol chlorination in a gas-liquid semibatch reactor:New catalysts for chlorohydrin production

    Institute of Scientific and Technical Information of China (English)

    R. Vitiello; V. Russo; R. Turco; R. Tesser; M. Di Serio; E. Santacesaria

    2014-01-01

    Glycerol from biodiesel production can be an important industrial feedstock for chemical commodi-ties as it can be used in the food, cosmetic, pharmaceutical and tobacco industries. However, crude glycerol derived from biodiesel production has a low value because of impurities. The purification of this glycerol into a high grade involves high costs and is not economically feasible for small and medium size plants. The glycerol conversion into chlorohydrins was studied using new homogene-ous catalysts and hydrochloric acid as chlorination agent. This is an interesting alternative route to epichlorohydrin and then to epoxy resins. The behavior of two series of homologous catalysts, gly-colic acid series (glycolic acid, di-glycolic acid and thio-glycolic acid) and amminoacid series (glu-tamic acid, aspartic acid and cysteine), were investigated for their activity and selectivity. Glycolic acids were more active than amminoacids. The pKa values had a strong influence on selectivity (mono-chlorohydrins/di-chlorohydrins) for the amminoacid series, which was not observed for the glycolic acids. A kinetic model and reaction mechanism developed in a previous work were used for interpreting the kinetic runs.

  5. Catalytic Intermediate Pyrolysis of Napier Grass in a Fixed Bed Reactor with ZSM-5, HZSM-5 and Zinc-Exchanged Zeolite-A as the Catalyst

    Directory of Open Access Journals (Sweden)

    Isah Yakub Mohammed

    2016-03-01

    Full Text Available The environmental impact from the use of fossil fuel cum depletion of the known fossil oil reserves has led to increasing interest in liquid biofuels made from renewable biomass. This study presents the first experimental report on the catalytic pyrolysis of Napier grass, an underutilized biomass source, using ZSM-5, 0.3HZSM-5 and zinc exchanged zeolite-A catalyst. Pyrolysis was conducted in fixed bed reactor at 600 °C, 30 °C/min and 7 L/min nitrogen flow rate. The effect of catalyst-biomass ratio was evaluated with respect to pyrolysis oil yield and composition. Increasing the catalyst loading from 0.5 to 1.0 wt % showed no significant decrease in the bio-oil yield, particularly, the organic phase and thereafter decreased at catalyst loadings of 2.0 and 3.0 wt %. Standard analytical methods were used to establish the composition of the pyrolysis oil, which was made up of various aliphatic hydrocarbons, aromatics and other valuable chemicals and varied greatly with the surface acidity and pore characteristics of the individual catalysts. This study has demonstrated that pyrolysis oil with high fuel quality and value added chemicals can be produced from pyrolysis of Napier grass over acidic zeolite based catalysts.

  6. Production of ultrapure hydrogen in a Pd-Ag membrane reactor using Ru/La{sub 2}O{sub 3} catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Faroldi, B.; Carrara, C.; Lombardo, E.A.; Cornaglia, L.M. [Instituto de Investigaciones en Catalisis y Petroquimica (FIQ, UNL-CONICET), Santiago del Estero, 2829-3000 Santa Fe (Argentina)

    2007-03-01

    Ru catalysts supported on lanthanum oxide with different loadings were prepared by wet impregnation. These solids were characterized by laser Raman spectroscopy (LSR), XPS, XRD and TPR. The catalytic activity toward hydrogen production through the dry reforming of methane was determined in a fixed-bed reactor and a membrane reactor. The reaction rate expressed per gram of Ru decreased when the metal loading increased. In the Pd-Ag membrane reactor, when the sweep gas flow rate (SG) increased, the conversions overcame the equilibrium values and the difference between CH{sub 4} and CO{sub 2} conversions decreased. Both Ru(0.6) and Ru(1.2) catalysts were able to restore the equilibrium for the dry reforming reaction up to values of SG = 30 ml min{sup -1}; Ru(0.6) was the most effective catalyst. By employing a CO{sub 2}/CH{sub 4} 1 and a SG of 0.05 mmol s{sup -1}, both a high H{sub 2} permeation flux of 5.68 x 10{sup -7} mol s{sup -1} m{sup -2} and a hydrogen recovery of 80% were obtained. Both the TPR and the Raman spectroscopy data indicated the presence of Ru(III) strongly interacting with La. Significantly, this observation was further confirmed by the appearance of Ru(III) on the surface. When the Ru content increased, the higher Ru 3d binding energy component was proposed as arising from Ru(IV). Concerning the Ru(1.2) solid, the presence of Ru(IV) was detected by means of TPR experiments, in agreement with the high proportion of Ru(IV) on the surface. Therefore, a fraction of Ru loading was present in this solid as species with weaker metal-support interaction leading to the slight deactivation of this catalyst in the membrane reactor. (author)

  7. 整体式催化剂催化过氧化氢异丙苯分解反应的模拟研究%Simulation study of decomposition reaction of cumene hydroperoxide over monolithic catalysts

    Institute of Scientific and Technical Information of China (English)

    智瑞彩; 韩丽; 张傑

    2014-01-01

    The relationship between the structure and catalytic performance of monolithic catalyst for the decomposition reaction of cumene hydroperoxide was studied,which provided reaction engineering foundation for its practical application and process amplification. The transmission and the reaction performances of monolithic catalysts for cumene hydroperoxide decomposition reaction were investigated by Fluent simulation software. A reliable mathematical model was established to examine the effects of operating parameters and structural parameters on its catalytic properties. It was found that cumene hydroperoxide conversion was reduced with the increase of the space velocity,cumene hydroperoxide concentration and pore diameter,in which space velocity had the greatest influence on catalytic properties. Moreover,the active component increased with the enhancement of coating thickness,which could improve cumene hydroperoxide conversion.%研究了整体式催化剂结构与催化过氧化氢异丙苯分解反应性能的对应关系,为其实际应用及过程放大提供反应工程学基础。采用Fluent模拟软件对整体式催化剂的传递与反应特性进行研究,建立可靠的数学模型并采用此数学模型考察装填整体式催化剂的反应器操作参数和结构参数对催化性能的影响。结果表明,过氧化氢异丙苯转化率随着空速、过氧化氢异丙苯浓度以及孔道直径的增大而降低,其中,空速对催化性能的影响最大。涂层厚度的增加使活性组分增加,提高过氧化氢异丙苯转化率。

  8. 甲醛装置主反应器(R3106/R3206)催化剂的装填%Formaldehyde plant main reactor catalyst loading

    Institute of Scientific and Technical Information of China (English)

    王雁平

    2011-01-01

    Formaldehyde plant of Tianye chemical industry co.,ltd.of cnooc chemical,ltd.is the introduction of foreign chemical patents and put into operation a new device.Catalyst loading quality is the key to the main reactor,related to the normal operation of the main reactor,this paper introduces Formaldehyde Reactor(R3106/R3206) structure,the role of catalyst and formaldehyde prior to catalyst loading removable mesh grille and catalyst loading method for peer exchange and discuss common.%甲醛装置是中海石油天野化工引进国外专利技术建成投产的又一套新装置。本文介绍了甲醛装置反应器(R 3106/R 3206)的结构,甲醛催化剂的作用以及装填前催化剂格栅丝网的拆装和催化剂的装填方法。

  9. Comparative study of fluidized-bed and fixed-bed reactor for syngas methanation over Ni-W/TiO2-SiO2catalyst

    Institute of Scientific and Technical Information of China (English)

    Bo; Liu; Shengfu; Ji

    2013-01-01

    In this work,syngas methanation over Ni-W/TiO2-SiO2catalyst was studied in a fluidized-bed reactor(FBR)and its performance was compared with a fixed-bed reactor(FIXBR).The effects of main operating variables including feedstock gases space velocity,coke content,bed temperature and sulfur-tolerant stability of 100 h life were investigated.The structure of the catalysts was characterized by XRD,N2adsorptiondesorption and TEM.It is found that under same space velocity from 5000 h 1to 25000 h 1FBR gave a higher CH4yield,lower coke content,and lower bed temperature than those obtained in FIXBR.Ni-W/TiO2-SiO2catalyst possessed excellent sulfur-tolerant stability on the feedstock gases less than 500 ppm H2S in FBR.The carbon deposits formed on the spent catalyst were in the form of carbon fibers in FBR,while in the form of dense accumulation distribution appearance in FIXBR.

  10. Impacts of halogen additions on mercury oxidation, in a slipstream selective catalyst reduction (SCR), reactor when burning sub-bituminous coal.

    Science.gov (United States)

    Cao, Yan; Gao, Zhengyang; Zhu, Jiashun; Wang, Quanhai; Huang, Yaji; Chiu, Chengchung; Parker, Bruce; Chu, Paul; Pant, Wei-Ping

    2008-01-01

    This paper presents a comparison of impacts of halogen species on the elemental mercury (Hg(0)) oxidation in a real coal-derived flue gas atmosphere. It is reported there is a higher percentage of Hg(0) in the flue gas when burning sub-bituminous coal (herein Powder River Basin (PRB) coal) and lignite, even with the use of selective catalytic reduction (SCR). The higher Hg(0)concentration in the flue gas makes it difficult to use the wet-FGD process for the mercury emission control in coal-fired utility boilers. Investigation of enhanced Hg(0) oxidation by addition of hydrogen halogens (HF, HCl, HBr, and HI) was conducted in a slipstream reactor with and without SCR catalysts when burning PRB coal. Two commercial SCR catalysts were evaluated. SCR catalyst no. 1 showed higher efficiencies of both NO reduction and Hg(0) oxidation than those of SCR catalyst no. 2. NH3 addition seemed to inhibit the Hg(0) oxidation, which indicated competitive processes between NH3 reduction and Hg(0) oxidation on the surface of SCR catalysts. The hydrogen halogens, in the order of impact on Hg(0) oxidation, were HBr, HI, and HCl or HF. Addition of HBr at approximately 3 ppm could achieve 80% Hg(0) oxidation. Addition of HI at approximately 5 ppm could achieve 40% Hg(0) oxidation. In comparison to the empty reactor, 40% Hg(0) oxidation could be achieved when HCl addition was up to 300 ppm. The enhanced Hg(0) oxidation by addition of HBr and HI seemed not to be correlated to the catalytic effects by both evaluated SCR catalysts. The effectiveness of conversion of hydrogen halogens to halogen molecules or interhalogens seemed to be attributed to their impacts on Hg(0) oxidation.

  11. Selective hydrogenolysis of raw glycerol to 1,2-propanediol over Cu-ZnO catalysts in fixed-bed reactor.

    Science.gov (United States)

    Gao, Qiang; Xu, Bolian; Tong, Qing; Fan, Yining

    2016-01-01

    The catalytic properties of Cu-ZnO catalysts for glycerol hydrogenolysis to 1,2-propanediol (1,2-PDO) were tested in a fixed-bed reactor at 250 °C and 2.0 MPa H2. The relation between composition, surface properties, and catalytic performance of glycerol hydrogenation of Cu-ZnO catalysts was studied using nitrogen adsorption (BET methods), XRD, H2 temperature-programmed reduction, and N2O chemisorptions. It was found that there was a close link between the surface CuO amount of Cu-ZnO catalyst and the reactivity for glycerol hydrogenation. The Cu-ZnO catalyst (Cu/Zn = 1.86) which had the highest surface Cu amount showed the best catalytic activity for glycerol hydrogenolysis. Furthermore, Cu-ZnO catalyst presented good stability and remarkable catalytic activity for glycerol hydrogenolysis to 1,2-PDO using raw glycerol derived from the fat saponification as feedstock.

  12. Parametric study of the decomposition of methane using a NiCu/Al{sub 2}O{sub 3} catalyst in a fluidized bed reactor

    Energy Technology Data Exchange (ETDEWEB)

    Pinilla, J.L.; Suelves, I.; Lazaro, M.J.; Moliner, R. [Instituto de Carboquimica, CSIC, Miguel Luesma Castan 4, 50018 Zaragoza (Spain); Palacios, J.M. [Instituto de Catalisis y Petroleoquimica, CSIC, Campus Universidad Autonoma, Cantoblanco, 28049 Madrid (Spain)

    2010-09-15

    CO{sub 2}-free production of hydrogen via catalytic decomposition of methane (CDM) was studied in a fluidized bed reactor (FBR) using a NiCu/Al{sub 2}O{sub 3} catalyst. A parametric study of the effects of some process variables, including catalyst particle size, reaction temperature, space velocity and the ratio of gas flow velocity to the minimum fluidization velocity (u{sub o}/u{sub mf}), was undertaken. A mean particle size of 150 {mu}m allows optimization of results in terms of hydrogen production without agglomeration problems. The operating conditions strongly affect the catalyst performance: hydrogen production was enhanced by increasing operating temperature and lowering space velocity. However, increases in operating temperature, space velocity and the ratio u{sub o}/u{sub mf} provoked increases in the catalyst deactivation rate. At 700 C, carbon was deposited as carbon nanofibers, while higher temperatures promoted the formation of encapsulating carbon, which led to rapid catalyst deactivation. (author)

  13. Microchannel Reactors for ISRU Applications

    Science.gov (United States)

    Carranza, Susana; Makel, Darby B.; Blizman, Brandon; Ward, Benjamin J.

    2005-02-01

    Affordable planning and execution of prolonged manned space missions depend upon the utilization of local resources and the waste products which are formed in manned spacecraft and surface bases. Successful in-situ resources utilization (ISRU) will require component technologies which provide optimal size, weight, volume, and power efficiency. Microchannel reactors enable the efficient chemical processing of in situ resources. The reactors can be designed for the processes that generate the most benefit for each mission. For instance, propellants (methane) can be produced from carbon dioxide from the Mars atmosphere using the Sabatier reaction and ethylene can be produced from the partial oxidation of methane. A system that synthesizes ethylene could be the precursor for systems to synthesize ethanol and polyethylene. Ethanol can be used as a nutrient for Astrobiology experiments, as well as the production of nutrients for human crew (e.g. sugars). Polyethylene can be used in the construction of habitats, tools, and replacement parts. This paper will present recent developments in miniature chemical reactors using advanced Micro Electro Mechanical Systems (MEMS) and microchannel technology to support ISRU of Mars and lunar missions. Among other applications, the technology has been demonstrated for the Sabatier process and for the partial oxidation of methane. Microchannel reactors were developed based on ceramic substrates as well as metal substrates. In both types of reactors, multiple layers coated with catalytic material are bonded, forming a monolithic structure. Such reactors are readily scalable with the incorporation of extra layers. In addition, this reactor structure minimizes pressure drop and catalyst settling, which are common problems in conventional packed bed reactors.

  14. Modeling Geometric Arrangements of TiO2-Based Catalyst Substrates and Isotropic Light Sources to Enhance the Efficiency of a Photocatalystic Oxidation (PCO) Reactor

    Science.gov (United States)

    Richards, Jeffrey T.; Levine, Lanfang H.; Husk, Geoffrey K.

    2011-01-01

    The closed confined environments of the ISS, as well as in future spacecraft for exploration beyond LEO, provide many challenges to crew health. One such challenge is the availability of a robust, energy efficient, and re-generable air revitalization system that controls trace volatile organic contaminants (VOCs) to levels below a specified spacecraft maximum allowable concentration (SMAC). Photocatalytic oxidation (PCO), which is capable of mineralizing VOCs at room temperature and of accommodating a high volumetric flow, is being evaluated as an alternative trace contaminant control technology. In an architecture of a combined air and water management system, placing a PCO unit before a condensing heat exchanger for humidity control will greatly reduce the organic load into the humidity condensate loop ofthe water processing assembly (WPA) thereby enhancing the life cycle economics ofthe WPA. This targeted application dictates a single pass efficiency of greater than 90% for polar VOCs. Although this target was met in laboratory bench-scaled reactors, no commercial or SBIR-developed prototype PCO units examined to date have achieved this goal. Furthermore, the formation of partial oxidation products (e.g., acetaldehyde) was not eliminated. It is known that single pass efficiency and partial oxidation are strongly dependent upon the contact time and catalyst illumination, hence the requirement for an efficient reactor design. The objective of this study is to maximize the apparent contact time and illuminated catalyst surface area at a given reactor volume and volumetric flow. In this study, a Ti02-based photocatalyst is assumed to be immobilized on porous substrate panels and illumination derived from linear isotropic light sources. Mathematical modeling using computational fluid dynamics (CFD) analyses were performed to investigate the effect of: 1) the geometry and configuration of catalyst-coated substrate panels, 2) porosity of the supporting substrate, and 3

  15. Routes for deactivation of different autothermal reforming catalysts

    Science.gov (United States)

    Pasel, Joachim; Wohlrab, Sebastian; Kreft, Stefanie; Rotov, Mikhail; Löhken, Katrin; Peters, Ralf; Stolten, Detlef

    2016-09-01

    Fuel cell systems with integrated autothermal reforming units require active and robust catalysts for H2 production. In pursuit of this, an experimental screening of catalysts utilized in the autothermal reforming of commercial diesel fuels is performed. The catalysts incorporate a monolithic cordierite substrate, an oxide support (γ-Al2O3, La-Al2O3, CeO2, Gd-CeO2, ZrO2, Y-ZrO2) and Rh as the active phase. Experiments are run by widely varying the O2/C and H2O/C molar ratios at different gas hourly space velocities. In most cases, this provokes accelerated catalyst deactivation and permits an informative comparison of the catalysts. Fresh and aged catalysts are characterized by temperature-programmed methods, thermogravimetry and transmission electron microscopy to find correlations with catalytic activity and stability. Using this approach, routes for catalyst deactivation are identified, together with causes of different catalytic activities. Suitable reaction conditions can be derived from our results for the operation of reactors for autothermal reforming at steady-state and under transient reaction conditions, which helps improve the efficiency and the stability of fuel cell systems.

  16. Treatment of a non-azo dye aqueous solution by CWAO in continuous reactor using a Ni catalyst derived from hydrotalcite-like precursor

    Energy Technology Data Exchange (ETDEWEB)

    Vallet, Ana, E-mail: avallet@quim.ucm.es [Grupo de Catalisis y Procesos de Separacion (CyPS), Departamento de Ingenieria Quimica, Facultad de Ciencias Quimicas, Universidad Complutense de Madrid, Avda. Complutense s/n, 28040 Madrid (Spain); Besson, Michele, E-mail: michele.besson@ircelyon.univ-lyon1.fr [IRCELYON, Institut de recherches sur la catalyse et l' environnement de Lyon, UMR5256 CNRS-Universite Lyon1, 2 Avenue Albert Einstein, F-69626 Villeurbanne Cedex (France); Ovejero, Gabriel; Garcia, Juan [Grupo de Catalisis y Procesos de Separacion (CyPS), Departamento de Ingenieria Quimica, Facultad de Ciencias Quimicas, Universidad Complutense de Madrid, Avda. Complutense s/n, 28040 Madrid (Spain)

    2012-08-15

    Highlights: Black-Right-Pointing-Pointer Ni supported over hydrotalcite calcined precursors as catalyst. Black-Right-Pointing-Pointer Catalytic wet air oxidation in trickle bed reactor for Basic Yellow 11 removal. Black-Right-Pointing-Pointer Dye removal depends on temperature, initial dye concentration and flow rate. Black-Right-Pointing-Pointer The catalyst proved to be stable and efficient for the dye degradation. - Abstract: Catalytic wet air oxidation (CWAO) of a Basic Yellow 11 (BY11) aqueous solution, chosen as a model of a hardly biodegradable non-azo dye was carried out in a continuous-flow trickle-bed reactor, using nickel supported over hydrotalcite precursor calcined at 550 Degree-Sign C. An increase in the reaction temperature (120-180 Degree-Sign C), and a decrease in dye concentration (1000-3000 ppm) or liquid flow rate (0.1-0.7 mL min{sup -1}) enhanced the CWAO performance in a 30 and 19% for the variation of the temperature and concentration respectively. After a small leaching observed within the first hours, the catalyst proved to be very stable during the 65-day reaction. The CWAO process was found to be very efficient, achieving BY11 conversion up to 95% and TOC conversion up to 85% at 0.1 mL min{sup -1} and 180 Degree-Sign C under 5 MPa air.

  17. Monoliths in Bioprocess Technology

    Directory of Open Access Journals (Sweden)

    Vignesh Rajamanickam

    2015-04-01

    Full Text Available Monolithic columns are a special type of chromatography column, which can be used for the purification of different biomolecules. They have become popular due to their high mass transfer properties and short purification times. Several articles have already discussed monolith manufacturing, as well as monolith characteristics. In contrast, this review focuses on the applied aspect of monoliths and discusses the most relevant biomolecules that can be successfully purified by them. We describe success stories for viruses, nucleic acids and proteins and compare them to conventional purification methods. Furthermore, the advantages of monolithic columns over particle-based resins, as well as the limitations of monoliths are discussed. With a compilation of commercially available monolithic columns, this review aims at serving as a ‘yellow pages’ for bioprocess engineers who face the challenge of purifying a certain biomolecule using monoliths.

  18. Raman studies of Rh and Pt on La{sub 2}O{sub 3} catalysts used in a membrane reactor for hydrogen production

    Energy Technology Data Exchange (ETDEWEB)

    Cornaglia, L.M.; Munera, J.; Irusta, S.; Lombardo, E.A. [Instituto de Investigaciones en Catalisis y Petroquimica, (FIQ, UNL-CONICET), Santiago del Estero 2829-3000 Santa Fe (Argentina)

    2004-05-28

    Rh and Pt catalysts supported on lanthanum oxide were prepared by wet impregnation. The solids were used in a Pd-Ag membrane reactor to produce hydrogen through the carbon dioxide reforming of methane. The effect of the sweep gas flow rate and W/F upon the conversions of CO{sub 2} and CH{sub 4}, as well as on the production of H{sub 2} was studied. The best performing catalyst was Rh (0.6%). It yielded a methane conversion 38% higher than the thermodynamic value and the highest H{sub 2} permeate flux across the membrane. Lanthanum phases on the support and the catalysts were characterized by Laser Raman spectroscopy, FTIR, and XRD. The support and the calcined fresh catalysts exhibited a mixture of phases which were influenced by the metal type. Furthermore, platinum seemed to favor the formation of Ia-La{sub 2}O{sub 2}CO{sub 3} after a short treatment in flowing CO{sub 2}. However, the only remaining crystalline phase after 100h on stream was II-La{sub 2}O{sub 2}CO{sub 3}. A small amount of graphitic carbon was detected using Laser Raman spectroscopy, despite the fact that no carbon deposition was observed through TGA measurements. The graphite crystallization order seemed to be dependent upon the contact time of the reactants.

  19. 钯催化剂2-乙基蒽醌加氢滴流床反应器模拟%SIMULATION OF TRICKLE-BED REACTOR FOR HYDROGENATION OF 2-ETHYLANTHRAQUINONE WITH PALLADIUM CATALYST

    Institute of Scientific and Technical Information of China (English)

    吕树祥; 王莅; 刘建国; 陈四海; 王亚权; 米镇涛

    2003-01-01

    Hydrogenation of 2-ethylanthraquinone is a key step in the industrial production of hydrogen peroxide via anthraquinone. This reaction on palladium-supported catalysts is normally carried out in trickle-bed reactors. A numerical model for simulation of a gas-liquid-solid hydrogenation trickle-bed reactor is presented. The model is based on the film theory and takes into account the axial dispersion effect on the performance of the reactor. Comparison of calculated values with data from pilot plant and industrial reactor shows that the agreement is quite satisfactory and the maximum variance is less than 5%. Gas-liquid and liquid-solid mass-transfer coefficients are determined by semi-empirical correlations available in the literature. The palladium-supported catalyst is extremely active and the reaction is always controlled by gas-liquid mass-transfer, and the overall effectiveness factor is always very low in agreement with the high catalytic activity of the palladium-supported catalyst. The overall effectiveness factor increases with decreasing catalyst hold-up. Therefore, it is feasible to improve the productivity of unit catalyst by decreasing the catalyst hold-up in a commercial plant with the hydrodynamic characters kept unchange.

  20. Catalytic wet air oxidation of bisphenol A solution in a batch-recycle trickle-bed reactor over titanate nanotube-based catalysts.

    Science.gov (United States)

    Kaplan, Renata; Erjavec, Boštjan; Senila, Marin; Pintar, Albin

    2014-10-01

    Catalytic wet air oxidation (CWAO) is classified as an advanced oxidation process, which proved to be highly efficient for the removal of emerging organic pollutant bisphenol A (BPA) from water. In this study, BPA was successfully removed in a batch-recycle trickle-bed reactor over bare titanate nanotube-based catalysts at very short space time of 0.6 min gCAT g(-1). The as-prepared titanate nanotubes, which underwent heat treatment at 600 °C, showed high activity for the removal of aqueous BPA. Liquid-phase recycling (5- or 10-fold recycle) enabled complete BPA conversion already at 200 °C, together with high conversion of total organic carbon (TOC), i.e., 73 and 98 %, respectively. The catalyst was chemically stable in the given range of operating conditions for 189 h on stream.

  1. CFD aided optimization of an innovative SCR catalyst design for heavy-duty marine diesel engines

    Science.gov (United States)

    Krastev, V. K.; Russo, S.; Verdemare, D.; Recine, G.; Biferale, L.; Falcucci, G.

    2016-06-01

    In this paper, the design of a new system for reducing NOx from exhaust gases from marine engines is shown. The core of the system is represented by the Selective Catalytic Reduction (SCR) reactor, in which the catalyst is made of titanium dioxide nano-fibers functionalized with metal oxides and deposited by electrospinning on a corrugated metal support. Compared to the current monolithic reactor designs, the high specific surface offered by the fibers allows in principle to satisfy the TIER III emission standards, with a consistent saving in the reactor volume. To optimize the reactor design process, a Computational Fluid Dynamics (CFD) model has been developed, alongside experimental measurements and numerical simulations. Results of different configurations are reported and critically assessed.

  2. Reactor

    Science.gov (United States)

    Evans, Robert M.

    1976-10-05

    1. A neutronic reactor having a moderator, coolant tubes traversing the moderator from an inlet end to an outlet end, bodies of material fissionable by neutrons of thermal energy disposed within the coolant tubes, and means for circulating water through said coolant tubes characterized by the improved construction wherein the coolant tubes are constructed of aluminum having an outer diameter of 1.729 inches and a wall thickness of 0.059 inch, and the means for circulating a liquid coolant through the tubes includes a source of water at a pressure of approximately 350 pounds per square inch connected to the inlet end of the tubes, and said construction including a pressure reducing orifice disposed at the inlet ends of the tubes reducing the pressure of the water by approximately 150 pounds per square inch.

  3. New insight in oxidative conversion of alkanes : exploring Li-promoted MgO catalysts and plasma micro-reactors

    NARCIS (Netherlands)

    Trionfetti, Cristiano

    2008-01-01

    In this study the preparation of Li-promoted MgO catalysts is described using, respectively, (i) wet impregnation and (ii) sol-gel method. In the case of Li-promoted MgO catalysts, defects sites, due to the surface substitution of Mg2+ ions by a Li+ ion in the MgO matrix, are reported to play a sign

  4. Monolithic Continuous-Flow Bioreactors

    Science.gov (United States)

    Stephanopoulos, Gregory; Kornfield, Julia A.; Voecks, Gerald A.

    1993-01-01

    Monolithic ceramic matrices containing many small flow passages useful as continuous-flow bioreactors. Ceramic matrix containing passages made by extruding and firing suitable ceramic. Pores in matrix provide attachment medium for film of cells and allow free movement of solution. Material one not toxic to micro-organisms grown in reactor. In reactor, liquid nutrients flow over, and liquid reaction products flow from, cell culture immobilized in one set of channels while oxygen flows to, and gaseous reaction products flow from, culture in adjacent set of passages. Cells live on inner surfaces containing flowing nutrient and in pores of walls of passages. Ready access to nutrients and oxygen in channels. They generate continuous high yield characteristic of immobilized cells, without large expenditure of energy otherwise incurred if necessary to pump nutrient solution through dense biomass as in bioreactors of other types.

  5. A micro-structured 5kW complete fuel processor for iso-octane as hydrogen supply system for mobile auxiliary power units Part I. Development of autothermal reforming catalyst and reactor

    OpenAIRE

    Kolb, Gunther; Baier, Tobias; Schürer, Jochen; Tiemann, David; Ziogas, Athanassios; Ehwald, Hermann; Alphonse, Pierre

    2008-01-01

    A micro-structured autothermal reformer was developed for a fuel processing/fuel cell system running on iso-octane and designed for an electrical power output of 5kWel. The target application was an automotive auxiliary power unit (APU). The work covered both catalyst and reactor development. In fixed bed screening, nickel and rhodium were identified as the best candidates for autothermal reforming of gasoline. Under higher feed flow rates applied in microchannel testing, a catalyst formul...

  6. A versatile elevated-pressure reactor combined with an ultrahigh vacuum surface setup for efficient testing of model and powder catalysts under clean gas-phase conditions

    Energy Technology Data Exchange (ETDEWEB)

    Morfin, Franck; Piccolo, Laurent [Institut de recherches sur la catalyse et l' environnement de Lyon (IRCELYON), UMR 5256 CNRS and Université Lyon 1, 2 avenue Albert Einstein, F-69626 Villeurbanne (France)

    2013-09-15

    A small-volume reaction cell for catalytic or photocatalytic testing of solid materials at pressures up to 1000 Torr has been coupled to a surface-science setup used for standard sample preparation and characterization under ultrahigh vacuum (UHV). The reactor and sample holder designs allow easy sample transfer from/to the UHV chamber, and investigation of both planar and small amounts of powder catalysts under the same conditions. The sample is heated with an infrared laser beam and its temperature is measured with a compact pyrometer. Combined in a regulation loop, this system ensures fast and accurate temperature control as well as clean heating. The reaction products are automatically sampled and analyzed by mass spectrometry and/or gas chromatography (GC). Unlike previous systems, our GC apparatus does not use a recirculation loop and allows working in clean conditions at pressures as low as 1 Torr while detecting partial pressures smaller than 10{sup −4} Torr. The efficiency and versatility of the reactor are demonstrated in the study of two catalytic systems: butadiene hydrogenation on Pd(100) and CO oxidation over an AuRh/TiO{sub 2} powder catalyst.

  7. Treatment of ammonia by catalytic wet oxidation process over platinum-rhodium bimetallic catalyst in a trickle-bed reactor: effect of pH.

    Science.gov (United States)

    Hung, Chang-Mao; Lin, Wei-Bang; Ho, Ching-Lin; Shen, Yun-Hwei; Hsia, Shao-Yi

    2010-08-01

    This work adopted aqueous solutions of ammonia for use in catalytic liquid-phase reduction in a trickle-bed reactor with a platinum-rhodium bimetallic catalyst, prepared by the co-precipitation of chloroplatinic acid (H2PtCl6) and rhodium nitrate [Rh(NO3)3]. The experimental results demonstrated that a minimal amount of ammonia was removed from the solution by wet oxidation in the absence of any catalyst, while approximately 97.0% of the ammonia was removed by wet oxidation over the platinum-rhodium bimetallic catalyst at 230 degrees C with an oxygen partial pressure of 2.0 MPa. The oxidation of ammonia has been studied as a function of pH, and the main reaction products were determined. A synergistic effect is manifest in the platinum-rhodium bimetallic structure, in which the material has the greatest capacity to reduce ammonia. The reaction pathway linked the oxidizing ammonia to nitric oxide, nitrogen, and water.

  8. Update On Monolithic Fuel Fabrication Development

    Energy Technology Data Exchange (ETDEWEB)

    C. R Clark; J. M. Wight; G. C. Knighton; G. A. Moore; J. F. Jue

    2005-11-01

    Efforts to develop a viable monolithic research reactor fuel plate have continued at Idaho National Laboratory. These efforts have concentrated on both fabrication process refinement and scale-up to produce full sized fuel plates. Advancements have been made in the production of U-Mo foil including full sized foils. Progress has also been made in the friction stir welding and transient liquid phase bonding fabrication processes resulting in better bonding, more stable processes and the ability to fabricate larger fuel plates.

  9. Selective oxidation of cyclohexene through gold functionalized silica monolith microreactors

    Science.gov (United States)

    Alotaibi, Mohammed T.; Taylor, Martin J.; Liu, Dan; Beaumont, Simon K.; Kyriakou, Georgios

    2016-04-01

    Two simple, reproducible methods of preparing evenly distributed Au nanoparticle containing mesoporous silica monoliths are investigated. These Au nanoparticle containing monoliths are subsequently investigated as flow reactors for the selective oxidation of cyclohexene. In the first strategy, the silica monolith was directly impregnated with Au nanoparticles during the formation of the monolith. The second approach was to pre-functionalize the monolith with thiol groups tethered within the silica mesostructure. These can act as evenly distributed anchors for the Au nanoparticles to be incorporated by flowing a Au nanoparticle solution through the thiol functionalized monolith. Both methods led to successfully achieving even distribution of Au nanoparticles along the length of the monolith as demonstrated by ICP-OES. However, the impregnation method led to strong agglomeration of the Au nanoparticles during subsequent heating steps while the thiol anchoring procedure maintained the nanoparticles in the range of 6.8 ± 1.4 nm. Both Au nanoparticle containing monoliths as well as samples with no Au incorporated were tested for the selective oxidation of cyclohexene under constant flow at 30 °C. The Au free materials were found to be catalytically inactive with Au being the minimum necessary requirement for the reaction to proceed. The impregnated Au-containing monolith was found to be less active than the thiol functionalized Au-containing material, attributable to the low metal surface area of the Au nanoparticles. The reaction on the thiol functionalized Au-containing monolith was found to depend strongly on the type of oxidant used: tert-butyl hydroperoxide (TBHP) was more active than H2O2, likely due to the thiol induced hydrophobicity in the monolith.

  10. Low-temperature upgrading of low-calorific biogas for CO2 mitigation using DBD-catalyst hybrid reactor

    Science.gov (United States)

    Nozaki, Tomohiro; Tsukijihara, Hiroyuki; Fukui, Wataru; Okazaki, Ken

    2006-10-01

    Although huge amounts of biogas, which consists of 20-60% of CH4 in CO2/N2, can be obtained from landfills, coal mines, and agricultural residues, most of them are simply flared and wasted: because global warming potential of biogas is 5-15 times as potent as CO2. Poor combustibility of such biogas makes it difficult to utilize in conventional energy system. The purpose of this project is to promote the profitable recovery of methane from poor biogas via non-thermal plasma technology. We propose low-temperature steam reforming of biogas using DBD generated in catalyst beds. Methane is partially converted into hydrogen, and then fed into internal combustion engines for improved ignition stability as well as efficient operation. Low-temperature steam reforming is beneficial because exhaust gas from an engine can be used to activate catalyst beds. Space velocity (3600-15000 hr-1), reaction temperature (300-650^oC), and energy cost (30-150 kJ per mol CH4) have been investigated with simulated biogas (20-60% CH4 in mixtures of CO2/N2). The DBD enhances reaction rate of CH4 by a factor of ten at given catalyst temperatures, which is a rate-determining step of methane steam reforming, while species concentration of upgraded biogas was governed by thermodynamic equilibrium in the presence of catalyst.

  11. Advanced Catalysis Technologies: Lanthanum Cerium Manganese Hexaaluminate Combustion Catalysts for Flat Plate Reactor for Compact Steam Reformers

    Science.gov (United States)

    2008-12-01

    E. Pocoroba, E.M. Johansson, S.G. Jaras, ”Aging Of Palladium, Platinum And Manganese-Based Combustion Catalysts For Biogas Applications,” Catalysis...M.J. Binder, “JP-8 Catalytic Cracking For Compact Fuel Processors,” Journal of Power Sources 129 (2004) 81-89. 12. P-O.F. Andersson, M

  12. Synthesis of Pt-Ni Octahedra in Continuous-Flow Droplet Reactors for the Scalable Production of Highly Active Catalysts toward Oxygen Reduction.

    Science.gov (United States)

    Niu, Guangda; Zhou, Ming; Yang, Xuan; Park, Jinho; Lu, Ning; Wang, Jinguo; Kim, Moon J; Wang, Liduo; Xia, Younan

    2016-06-01

    A number of groups have reported the syntheses of nanosized Pt-Ni octahedra with remarkable activities toward the oxygen reduction reaction (ORR), a process key to the operation of proton-exchange membrane fuel cells. However, the throughputs of those batch-based syntheses are typically limited to a scale of 5-25 mg Pt per batch, which is far below the amount needed for commercial evaluation. Here we report the use of droplet reactors for the continuous and scalable production of Pt-Ni octahedra with high activities toward ORR. In a typical synthesis, Pt(acac)2, Ni(acac)2, and W(CO)6 were dissolved in a mixture of oleylamine, oleic acid, and benzyl ether, and then pumped into a polytetrafluoroethylene tube. When the solution entered the reaction zone at a temperature held in the range of 170-230 °C, W(CO)6 quickly decomposed to generate CO gas, naturally separating the reaction solution into discrete, uniform droplets. Each droplet then served as a reactor for the nucleation and growth of Pt-Ni octahedra whose size and composition could be controlled by changing the composition of the solvent and/or adjusting the amount of Ni(acac)2 added into the reaction solution. For a catalyst based on Pt2.4Ni octahedra of 9 nm in edge length, it showed an ORR mass activity of 2.67 A mgPt(-1) at 0.9 V, representing an 11-fold improvement over a state-of-the-art commercial Pt/C catalyst (0.24 A mgPt(-1)).

  13. KINETIC MODELING OF A FISCHER-TROPSCH REACTION OVER A COBALT CATALYST IN A SLURRY BUBBLE COLUMN REACTOR FOR INCORPORATION INTO A COMPUTATIONAL MULTIPHASE FLUID DYNAMICS MODEL

    Energy Technology Data Exchange (ETDEWEB)

    Anastasia Gribik; Doona Guillen, PhD; Daniel Ginosar, PhD

    2008-09-01

    Currently multi-tubular fixed bed reactors, fluidized bed reactors, and slurry bubble column reactors (SBCRs) are used in commercial Fischer Tropsch (FT) synthesis. There are a number of advantages of the SBCR compared to fixed and fluidized bed reactors. The main advantage of the SBCR is that temperature control and heat recovery are more easily achieved. The SBCR is a multiphase chemical reactor where a synthesis gas, comprised mainly of H2 and CO, is bubbled through a liquid hydrocarbon wax containing solid catalyst particles to produce specialty chemicals, lubricants, or fuels. The FT synthesis reaction is the polymerization of methylene groups [-(CH2)-] forming mainly linear alkanes and alkenes, ranging from methane to high molecular weight waxes. The Idaho National Laboratory is developing a computational multiphase fluid dynamics (CMFD) model of the FT process in a SBCR. This paper discusses the incorporation of absorption and reaction kinetics into the current hydrodynamic model. A phased approach for incorporation of the reaction kinetics into a CMFD model is presented here. Initially, a simple kinetic model is coupled to the hydrodynamic model, with increasing levels of complexity added in stages. The first phase of the model includes incorporation of the absorption of gas species from both large and small bubbles into the bulk liquid phase. The driving force for the gas across the gas liquid interface into the bulk liquid is dependent upon the interfacial gas concentration in both small and large bubbles. However, because it is difficult to measure the concentration at the gas-liquid interface, coefficients for convective mass transfer have been developed for the overall driving force between the bulk concentrations in the gas and liquid phases. It is assumed that there are no temperature effects from mass transfer of the gas phases to the bulk liquid phase, since there are only small amounts of dissolved gas in the liquid phase. The product from the

  14. Efficient Synthesis of Ethanol from CH4 and Syngas on a Cu-Co/TiO2 Catalyst Using a Stepwise Reactor

    Science.gov (United States)

    Zuo, Zhi-Jun; Peng, Fen; Huang, Wei

    2016-01-01

    Ethanol synthesis from CH4 and syngas on a Cu-Co/TiO2 catalyst is studied using experiments, density functional theory (DFT) and microkinetic modelling. The experimental results indicate that the active sites of ethanol synthesis from CH4 and syngas are Cu and CoO, over which the ethanol selectivity is approximately 98.30% in a continuous stepwise reactor. DFT and microkinetic modelling results show that *CH3 is the most abundant species and can be formed from *CH4 dehydrogenation or through the process of *CO hydrogenation. Next, the insertion of *CO into *CH3 forms *CH3CO. Finally, ethanol is formed through *CH3CO and *CH3COH hydrogenation. According to our results, small particles of metallic Cu and CoO as well as a strongly synergistic effect between metallic Cu and CoO are beneficial for ethanol synthesis from CH4 and syngas on a Cu-Co/TiO2 catalyst. PMID:27694944

  15. Enhanced Performance of Oxidation of Rosalva (9-decen-1-ol to Costenal (9-decenal on Porous Silicon-Supported Silver Catalyst in a Microstructured Reactor

    Directory of Open Access Journals (Sweden)

    Enhong Cao

    2014-01-01

    Full Text Available The use of metal-assisted HF chemical etching as a convenient technique to produce a few microns thick porous layer in silicon microchannels was demonstrated. Gas phase selective oxidation of rosalva to its aldehyde (costenal was performed in glass/silicon microstructured reactors at temperatures of 375–475 °C on silver catalyst which was deposited on both porous and flat silicon surface by sputter-coating. The effects of temperature (375–475 °C, rosalva concentration (1.17%–3.43%, O2 to rosalva ratio (0.5–20 and residence time on the reaction were investigated. The reactivity of rosalva on the porous silicon supported silver was 5.7–6.4 times higher than on the thin film silver catalyst at 450 °C. Furthermore, activation energy for the porous silicon supported silver was lower. Isothermal conditions in the microreactors allowed high conversion and selectivity to be achieved in a wide range of temperature and oxygen concentration. At typical reaction conditions (1.75% rosalva, O2/rosalva = 3, residence time 18 ms and 450 °C, conversion of 97% and selectivity of 95% to costenal was achieved, corresponding to a turnover frequency of 268 h−1.

  16. Effects of Catalysts and Membranes on the Performance of Membrane Reactors in Steam Reforming of Ethanol at Moderate Temperature

    Directory of Open Access Journals (Sweden)

    Manabu Miyamoto

    2016-06-01

    Full Text Available Steam reforming of ethanol in the membrane reactor using the Pd77Ag23 membrane was evaluated in Ni/CeO2 and Co/CeO2 at atmospheric pressure. At 673 K, the H2 yield in the Pd77Ag23 membrane reactor over Co/CeO2 was found to be higher than that over Ni/CeO2, although the H2 yield over Ni/CeO2 exceeded that over Co/CeO2 at 773 K. This difference was owing to their reaction mechanism. At 773 K, the effect of H2 removal could be understood as the equilibrium shift. In contrast, the H2 removal kinetically inhibited the reverse methane steam reforming at low temperature. Thus, the low methane-forming reaction rate of Co/CeO2 was favorable at 673 K. The addition of a trace amount of Ru increased the H2 yield effectively in the membrane reactor, indicating that a reverse H2 spill over mechanism of Ru would enhance the kinetical effect of H2 separation. Finally, the effect of membrane performance on the reactor performance by using amorphous alloy membranes with different compositions was evaluated. The H2 yield was set in the order of H2 permeation flux regardless of the membrane composition.

  17. STUDY OF MERCURY OXIDATION BY SCR CATALYST IN AN ENTRAINED-FLOW REACTOR UNDER SIMULATED PRB CONDITIONS

    Science.gov (United States)

    A bench-scale entrained-flow reactor system was constructed for studying elemental mercury oxidation under selective catalytic reduction (SCR) reaction conditions. Simulated flue gas was doped with fly ash collected from a subbituminous Powder River Basin (PRB) coal-fired boiler ...

  18. Plant oil-based shape memory polymer using acrylic monolith

    Directory of Open Access Journals (Sweden)

    T. Tsujimoto

    2015-09-01

    Full Text Available This article deals with the synthesis of a plant oil-based material using acrylic monolith. An acrylic monolith bearing oxirane groups was prepared via simple technique that involved the dissolution of poly(glycidyl methacrylate-comethyl methacrylate (PGMA in ethanolic – aqueous solution by heating and subsequent cooling. The PGMA monolith had topologically porous structure, which was attributed to the phase separation of the polymer solution. The PGMA monolith was impregnated by epoxidized soybean oil (ESO containing thermally-latent catalyst, and the subsequent curing produced a crosslinked material with relatively good transparency. The Young’s modulus and the tensile strength of polyESO/PGMA increased compared with the ESO homopolymer. The strain at break of polyESO/PGMA was larger than that of the ESO homopolymer and crosslinked PGMA. Furthermore, polyESO/PGMA exhibited good shape memory-recovery behavior.

  19. Mesoporous silica supported multiple single-site catalysts and polyethylene reactor blends with tailor-made trimodal and ultra-broad molecular weight distributions.

    Science.gov (United States)

    Kurek, Alexander; Mark, Stefan; Enders, Markus; Kristen, Marc O; Mülhaupt, Rolf

    2010-08-03

    A ternary blend of the bisiminopyridine chromium (III) (Cr-1) with the bisiminopyridine iron (II) (Fe-2) post-metallocenes with the quinolylsilylcyclopentadienyl chromium (III) halfsandwich complex (Cr-3) was supported on mesoporous silica to produce novel multiple single-site catalysts and polyethylene reactor blends with tailor-made molecular weight distributions (MWDs). The preferred cosupporting sequence of this ternary blend on MAO-treated silica was Fe-2 followed by Cr-1 and Cr-3. Cosupporting does not impair the single-site nature of the blend components producing polyethylene fractions with $\\overline M _{\\rm w}$ = 10(4) g · mol(-1) on Cr-1, $\\overline M _{\\rm w}$ = 3 × 10(5) g · mol(-1) on Fe-2, and $\\overline M _{\\rm w}$ = 3 × 10(6) g · mol(-1) on Cr-3. As a function of the Fe-2/Cr-1/Cr-2 mixing ratio it is possible to control the weight ratio of these three polyethylenes without affecting the individual average molecular weights and narrow polydispersities of the three polyethylene fractions. Tailor-made polyethylene reactor blends with ultra-broad MWD and polydispersities varying between 10 and 420 were obtained. When the molar ratio of Fe-2/Cr-1 was constant, the ultra-high molecular polyethylene (UHMWPE, $\\overline M _{\\rm w}$ > 10(6) g · mol(-1) ) content was varied between 8 and 16 wt.-% as a function of the Cr-3 content without impairing the blend ratio of the other two polyethylene fractions and without sacrificing melt processability. When the molar ratio Fe-2/Cr-3 was constant, it was possible to selectively increase the content of the low molecular weight fraction by additional cosupporting of Cr-1. Due to the intimate mixing of low and ultra-high molecular weight polyethylenes (UHMPEs) produced on cosupported single-site catalysts a wide range of melt processable polyethylene reactor blends was obtained.

  20. A high-throughput reactor system for optimization of Mo–V–Nb mixed oxide catalyst composition in ethane ODH

    KAUST Repository

    Zhu, Haibo

    2015-01-01

    75 Mo-V-Nb mixed oxide catalysts with a broad range of compositions were prepared by a simple evaporation method, and were screened for the ethane oxidative dehydrogenation (ODH) reaction. The compositions of these 75 catalysts were systematically changed by varying the Nb loading, and the Mo/V molar ratio. Characterization by XRD, XPS, H2-TPR and SEM revealed that an intimate structure is formed among the 3 components. The strong interaction among different components leads to the formation of a new phase or an "intimate structure". The dependency of conversion and selectivity on the catalyst composition was clearly demonstrated from the results of high-throughput testing. The optimized Mo-V-Nb molar composition was confirmed to be composed of a Nb content of 4-8%, a Mo content of 70-83%, and a V content of 12-25%. The enhanced catalytic performance of the mixed oxides is obviously due to the synergistic effects of the different components. The optimized compositions for ethane ODH revealed in our high-throughput tests and the structural information provided by our characterization studies can serve as the starting point for future efforts to improve the catalytic performance of Mo-V-Nb oxides. This journal is © The Royal Society of Chemistry.

  1. Monolithic supports with unique geometries and enhanced mass transfer.

    Energy Technology Data Exchange (ETDEWEB)

    Stuecker, John Nicholas; Ferrizz, Robert Matthew; Cesarano, Joseph, III; Miller, James Edward

    2004-01-01

    The catalytic combustion of natural gas has been the topic of much research over the past decade. Interest in this technology results from a desire to decrease or eliminate the emissions of harmful nitrogen oxides (NOX) from gas turbine power plants. A low-pressure drop catalyst support, such as a ceramic monolith, is ideal for this high-temperature, high-flow application. A drawback to the traditional honeycomb monoliths under these operating conditions is poor mass transfer to the catalyst surface in the straight-through channels. 'Robocasting' is a unique process developed at Sandia National Laboratories that can be used to manufacture ceramic monoliths with alternative 3-dimensional geometries, providing tortuous pathways to increase mass transfer while maintaining low pressure drops. This report details the mass transfer effects for novel 3-dimensional robocast monoliths, traditional honeycomb-type monoliths, and ceramic foams. The mass transfer limit is experimentally determined using the probe reaction of CO oxidation over a Pt / {gamma}-Al{sub 2}O{sub 3} catalyst, and the pressure drop is measured for each monolith sample. Conversion versus temperature data is analyzed quantitatively using well-known dimensionless mass transfer parameters. The results show that, relative to the honeycomb monolith support, considerable improvement in mass transfer efficiency is observed for robocast samples synthesized using an FCC-like geometry of alternating rods. Also, there is clearly a trade-off between enhanced mass transfer and increased pressure drop, which can be optimized depending on the particular demands of a given application.

  2. Reactor vessel

    OpenAIRE

    Makkee, M.; Kapteijn, F.; Moulijn, J.A

    1999-01-01

    A reactor vessel (1) comprises a reactor body (2) through which channels (3) are provided whose surface comprises longitudinal inwardly directed parts (4) and is provided with a catalyst (6), as well as buffer bodies (8, 12) connected to the channels (3) on both sides of the reactor body (2) and comprising connections for supplying (9, 10, 11) and discharging (13, 14, 15) via the channels (3) gases and/or liquids entering into a reaction with each other and substances formed upon this reactio...

  3. A kinetic study of methanol synthesis in a slurry reactor using a CuO/ZnO/Al sub 2 O sub 3 catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Al-Adwani, H.A.

    1992-05-01

    A kinetic model that describes the methanol production rate over a CuO/ZnO/AI{sub 2}0{sub 3} catalyst (United Catalyst L-951) at typical industrial operating conditions is developed using a slurry reactor. Different experiments are conducted in which the H{sub 2}/(CO+CO{sub 2}) ratio is equal to 2, 1, and 0.5, respectively, while the CO/CO{sub 2} ratio is held constant at 9. At each H{sub 2}/(CO+CO{sub 2}) ratio the space velocity is set at four different values in the range of 3000-13,000 1/hr kg{sub cat}. The effect of H{sub 2}/(CO+CO{sub 2}) ratio and space velocity on methanol production rate, conversions, and product composition is further investigated. The results indicate that the highest methanol production rate can be achieved at H{sub 2}/(CO+CO{sub 2}) ratio of 1 followed by H{sub 2}/(CO+CO{sub 2}) ratio of 0.5 and 2 respectively. The hydrogen and carbon monoxide conversions decrease with increasing space velocity for all H{sub 2}/(CO+CO{sub 2}) ratios tested. Carbon monoxide hydrogenation appears to be the main route to methanol at H{sub 2}/(CO+CO{sub 2}) ratio of 0.5 and 2. On the other hand, carbon dioxide hydrogenation appears to be the main route to methanol at H{sub 2}/(CO+CO{sub 2}) ratio of 1. At all H{sub 2}/(CO+CO{sub 2}) ratios, the extent of the reverse water gas shift reaction decreases with increasing space velocity. The effect of temperature on the kinetics is examined by using the same experimental approach at 508 K. It is found that a different reaction sequence takes place at each temperature. Also, a time on stream study is conducted simultaneously in order to investigate the characteristic of catalyst deactivation with time on stream. During the first 150 hours of time on stream, the catalyst loses approximately 2/3 of its initial activity before reaching a steady state activity.

  4. A kinetic study of methanol synthesis in a slurry reactor using a CuO/ZnO/Al{sub 2}O{sub 3} catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Al-Adwani, H.A.

    1992-05-01

    A kinetic model that describes the methanol production rate over a CuO/ZnO/AI{sub 2}0{sub 3} catalyst (United Catalyst L-951) at typical industrial operating conditions is developed using a slurry reactor. Different experiments are conducted in which the H{sub 2}/(CO+CO{sub 2}) ratio is equal to 2, 1, and 0.5, respectively, while the CO/CO{sub 2} ratio is held constant at 9. At each H{sub 2}/(CO+CO{sub 2}) ratio the space velocity is set at four different values in the range of 3000-13,000 1/hr kg{sub cat}. The effect of H{sub 2}/(CO+CO{sub 2}) ratio and space velocity on methanol production rate, conversions, and product composition is further investigated. The results indicate that the highest methanol production rate can be achieved at H{sub 2}/(CO+CO{sub 2}) ratio of 1 followed by H{sub 2}/(CO+CO{sub 2}) ratio of 0.5 and 2 respectively. The hydrogen and carbon monoxide conversions decrease with increasing space velocity for all H{sub 2}/(CO+CO{sub 2}) ratios tested. Carbon monoxide hydrogenation appears to be the main route to methanol at H{sub 2}/(CO+CO{sub 2}) ratio of 0.5 and 2. On the other hand, carbon dioxide hydrogenation appears to be the main route to methanol at H{sub 2}/(CO+CO{sub 2}) ratio of 1. At all H{sub 2}/(CO+CO{sub 2}) ratios, the extent of the reverse water gas shift reaction decreases with increasing space velocity. The effect of temperature on the kinetics is examined by using the same experimental approach at 508 K. It is found that a different reaction sequence takes place at each temperature. Also, a time on stream study is conducted simultaneously in order to investigate the characteristic of catalyst deactivation with time on stream. During the first 150 hours of time on stream, the catalyst loses approximately 2/3 of its initial activity before reaching a steady state activity.

  5. MONOLITHIC FUEL FABRICATION PROCESS DEVELOPMENT AT THE IDAHO NATIONAL LABORATORY_

    Energy Technology Data Exchange (ETDEWEB)

    G. A. Moore; F. J. Rice; N. E. Woolstenhulme; J-F. Jue; B. H. Park; S. E. Steffler; N. P. Hallinan; M. D. Chapple; M. C. Marshall; B. L. Mackowiak; C. R. Clark; B. H. Rabin

    2009-11-01

    Full-size/prototypic U10Mo monolithic fuel-foils and aluminum clad fuel plates are being developed at the Idaho National Laboratory’s (INL) Materials and Fuels Complex (MFC). These efforts are focused on realizing Low Enriched Uranium (LEU) high density monolithic fuel plates for use in High Performance Research and Test Reactors. The U10Mo fuel foils under development afford a fuel meat density of ~16 gU/cc and thus have the potential to facilitate LEU conversions without any significant reactor-performance penalty. An overview is provided of the ongoing monolithic UMo fuel development effort, including application of a zirconium barrier layer on fuel foils, fabrication scale-up efforts, and development of complex/graded fuel foils. Fuel plate clad bonding processes to be discussed include: Hot Isostatic Pressing (HIP) and Friction Bonding (FB).

  6. Treatment of a non-azo dye aqueous solution by CWAO in continuous reactor using a Ni catalyst derived from hydrotalcite-like precursor.

    Science.gov (United States)

    Vallet, Ana; Besson, Michèle; Ovejero, Gabriel; García, Juan

    2012-08-15

    Catalytic wet air oxidation (CWAO) of a Basic Yellow 11 (BY11) aqueous solution, chosen as a model of a hardly biodegradable non-azo dye was carried out in a continuous-flow trickle-bed reactor, using nickel supported over hydrotalcite precursor calcined at 550°C. An increase in the reaction temperature (120-180°C), and a decrease in dye concentration (1000-3000 ppm) or liquid flow rate (0.1-0.7 mL min(-1)) enhanced the CWAO performance in a 30 and 19% for the variation of the temperature and concentration respectively. After a small leaching observed within the first hours, the catalyst proved to be very stable during the 65-day reaction. The CWAO process was found to be very efficient, achieving BY11 conversion up to 95% and TOC conversion up to 85% at 0.1 mL min(-1) and 180°C under 5 MPa air.

  7. OXIDATION OF MERCURY ACROSS SCR CATALYSTS IN COAL-FIRED POWER PLANTS BURNING LOW RANK FUELS

    Energy Technology Data Exchange (ETDEWEB)

    Constance Senior; Temi Linjewile

    2003-10-31

    This is the third Quarterly Technical Report for DOE Cooperative Agreement No: DE-FC26-03NT41728. The objective of this program is to measure the oxidation of mercury in flue gas across SCR catalyst in a coal-fired power plant burning low rank fuels using a slipstream reactor containing multiple commercial catalysts in parallel. The Electric Power Research Institute (EPRI) and Argillon GmbH are providing co-funding for this program. This program contains multiple tasks and good progress is being made on all fronts. During this quarter, the second set of mercury measurements was made after the catalysts had been exposed to flue gas for about 2,000 hours. There was good agreement between the Ontario Hydro measurements and the SCEM measurements. Carbon trap measurements of total mercury agreed fairly well with the SCEM. There did appear to be some loss of mercury in the sampling system toward the end of the sampling campaign. NO{sub x} reductions across the catalysts ranged from 60% to 88%. Loss of total mercury across the commercial catalysts was not observed, as it had been in the March/April test series. It is not clear whether this was due to aging of the catalyst or to changes in the sampling system made between March/April and August. In the presence of ammonia, the blank monolith showed no oxidation. Two of the commercial catalysts showed mercury oxidation that was comparable to that in the March/April series. The other three commercial catalysts showed a decrease in mercury oxidation relative to the March/April series. Oxidation of mercury increased without ammonia present. Transient experiments showed that when ammonia was turned on, mercury appeared to desorb from the catalyst, suggesting displacement of adsorbed mercury by the ammonia.

  8. Monolithic microwave integrated circuits

    Science.gov (United States)

    Pucel, R. A.

    Monolithic microwave integrated circuits (MMICs), a new microwave technology which is expected to exert a profound influence on microwave circuit designs for future military systems as well as for the commercial and consumer markets, is discussed. The book contains an historical discussion followed by a comprehensive review presenting the current status in the field. The general topics of the volume are: design considerations, materials and processing considerations, monolithic circuit applications, and CAD, measurement, and packaging techniques. All phases of MMIC technology are covered, from design to testing.

  9. OXIDATION OF MERCURY ACROSS SCR CATALYSTS IN COAL-FIRED POWER PLANTS BURNING LOW RANK FUELS

    Energy Technology Data Exchange (ETDEWEB)

    Constance Senior

    2004-12-31

    The objectives of this program were to measure the oxidation of mercury in flue gas across SCR catalyst in a coal-fired power plant burning low rank fuels using a slipstream reactor containing multiple commercial catalysts in parallel and to develop a greater understanding of mercury oxidation across SCR catalysts in the form of a simple model. The Electric Power Research Institute (EPRI) and Argillon GmbH provided co-funding for this program. REI used a multicatalyst slipstream reactor to determine oxidation of mercury across five commercial SCR catalysts at a power plant that burned a blend of 87% subbituminous coal and 13% bituminous coal. The chlorine content of the blend was 100 to 240 {micro}g/g on a dry basis. Mercury measurements were carried out when the catalysts were relatively new, corresponding to about 300 hours of operation and again after 2,200 hours of operation. NO{sub x}, O{sub 2} and gaseous mercury speciation at the inlet and at the outlet of each catalyst chamber were measured. In general, the catalysts all appeared capable of achieving about 90% NO{sub x} reduction at a space velocity of 3,000 hr{sup -1} when new, which is typical of full-scale installations; after 2,200 hours exposure to flue gas, some of the catalysts appeared to lose NO{sub x} activity. For the fresh commercial catalysts, oxidation of mercury was in the range of 25% to 65% at typical full-scale space velocities. A blank monolith showed no oxidation of mercury under any conditions. All catalysts showed higher mercury oxidation without ammonia, consistent with full-scale measurements. After exposure to flue gas for 2,200 hours, some of the catalysts showed reduced levels of mercury oxidation relative to the initial levels of oxidation. A model of Hg oxidation across SCRs was formulated based on full-scale data. The model took into account the effects of temperature, space velocity, catalyst type and HCl concentration in the flue gas.

  10. Session 4: Bio-diesel fuel (BDF) production by the trans-esterification of soybean and castor oils and the esterification of fatty acid using fixed bed reactor with solid super-acid and amorphous zirconia catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Satoshi, Furuta; Kyoji, Yano [Petroleum Refining Research and Technology Center, Japan Energy Corporation Niizo-minami, Toda, Saitama (Japan); Hiromi, Matsuhashi; Kazushi, Arata [Hokkaido University of Education, Dept. of Science, Hakodate (Japan)

    2004-07-01

    The monoesters produced by trans-esterification of vegetable oils with alcohol are known as bio-diesel fuel. Most of the bio-diesel fuels are currently made using alkaline catalysts, because the trans-esterification reaction by homogeneous acid catalysts are much slower than that by alkaline catalysts. There are several comprehensive studies of base catalyzed transesterification. The alkaline catalysts show high performance for obtaining vegetable oils with high quality, but a question often arises; that is, the oils contain significant amounts of free fatty acids, which cannot be converted into bio-diesels but to a lot of soap. As for solid catalysts, the uses of acid catalysts are quite few in contrast to solid bases. It appears that solid super-acids promote the trans-esterification of vegetable oils as well as the esterification of free fatty acids. Sulfated zirconia (SO{sub 4}/ZrO{sub 2}: SZA) and tungstate zirconia (WO{sub 3}/ZrO{sub 2}: WZA) are typical examples of those super acids and exhibit high catalytic activities for various reactions. Sulfated tin oxide (SO{sub 4}/SnO{sub 2}: STO) is one of the candidates with strong acidity on the surface. It has been reported that the acid strength is higher than that of SZ. This study was aimed to apply three types of solid super-acid catalysts and two types of amorphous zirconia catalysts to the transesterification of soybean oil and the esterification of normal octanoic acid with methanol. We also found that amorphous zirconia, doped with Al and Ti (Al/Zr, Ti/Zr), show high activities for the transesterification. The trans-esterification reaction was conducted in a fixed-bed once-through reactor with 4.0 g of catalyst. Methanol (4.4 g/h) and soybean oil (3.0 g/h), 40 in the molar ratio, were supplied to the reactor for 21 hrs. All catalysts showed little deactivation with time for WZA as an example. WZA together with amorphous zirconia, Al/Zr and Ti/Zr, showed quite high performance for the trans

  11. 磁性催化剂与磁稳定床反应器或磁集成强化反应过程%Intensification catalytic reaction by integration of magnetic catalyst and magnetically stabilized bed reactor or magnetic separator

    Institute of Scientific and Technical Information of China (English)

    宗保宁

    2012-01-01

    通过将非晶态镍合金催化剂的磁性和加氢活性与磁稳定床反应器集成,实现了在己内酰胺加氢精制过程的工业应用.磁稳定床加氢精制替代己内酰胺氧化精制过程,显著提高了反应过程的能效和物效,并减少了污染物排放.非晶态镍合金催化剂与磁分离集成,强化了苯甲酸加氢反应过程.磁性Pd/Al2O3和NiSO4/Al2O3催化剂与磁稳定床反应器集成,强化了乙炔选择性加氢反应和烯烃叠合反应,形成了新技术生长点.%Utilizing the excellent hydrogenation activity and magnetism of the amorphous Ni catalyst, a magnetically stabilized bed reactor was developed for the purification of caprolactam, to ensure higher reactor and process efficiency. Integration of amorphous Ni catalyst and magnetic separator has enhanced the benzoic acid hydrogenation reaction to reduce the Pd/C catalyst consumption by 50%, and to increase the plant output by 15%, respectively. Integration of the appropriate magnetic catalyst into the magnetically stabilized bed reactor also allowed improved performances in selective hydrogenation of acetylene and olefin oligomerization, compared with current processes, and thus constitutes a highly effective technique for process intensification.

  12. Embedded-monolith armor

    Science.gov (United States)

    McElfresh, Michael W.; Groves, Scott E; Moffet, Mitchell L.; Martin, Louis P.

    2016-07-19

    A lightweight armor system utilizing a face section having a multiplicity of monoliths embedded in a matrix supported on low density foam. The face section is supported with a strong stiff backing plate. The backing plate is mounted on a spall plate.

  13. FLUIDIZED BED STEAM REFORMER MONOLITH FORMATION

    Energy Technology Data Exchange (ETDEWEB)

    Jantzen, C

    2006-12-22

    Fluidized Bed Steam Reforming (FBSR) is being considered as an alternative technology for the immobilization of a wide variety of aqueous high sodium containing radioactive wastes at various DOE facilities in the United States. The addition of clay, charcoal, and a catalyst as co-reactants converts aqueous Low Activity Wastes (LAW) to a granular or ''mineralized'' waste form while converting organic components to CO{sub 2} and steam, and nitrate/nitrite components, if any, to N{sub 2}. The waste form produced is a multiphase mineral assemblage of Na-Al-Si (NAS) feldspathoid minerals with cage-like structures that atomically bond radionuclides like Tc-99 and anions such as SO{sub 4}, I, F, and Cl. The granular product has been shown to be as durable as LAW glass. Shallow land burial requires that the mineralized waste form be able to sustain the weight of soil overburden and potential intrusion by future generations. The strength requirement necessitates binding the granular product into a monolith. FBSR mineral products were formulated into a variety of monoliths including various cements, Ceramicrete, and hydroceramics. All but one of the nine monoliths tested met the <2g/m{sup 2} durability specification for Na and Re (simulant for Tc-99) when tested using the Product Consistency Test (PCT; ASTM C1285). Of the nine monoliths tested the cements produced with 80-87 wt% FBSR product, the Ceramicrete, and the hydroceramic produced with 83.3 wt% FBSR product, met the compressive strength and durability requirements for an LAW waste form.

  14. Feasibility of the preparation of silica monoliths for gas chromatography: fast separation of light hydrocarbons.

    Science.gov (United States)

    Azzouz, Imadeddine; Essoussi, Anouar; Fleury, Joachim; Haudebourg, Raphael; Thiebaut, Didier; Vial, Jerome

    2015-02-27

    The preparation conditions of silica monoliths for gas chromatography were investigated. Silica-based monolithic capillary columns based on sol-gel process were tested in the course of high-speed gas chromatographic separations of light hydrocarbons mixture (C1-C4). The impact of modifying the amount of porogen and/or catalyst on the monolith properties were studied. At the best precursor/catalyst/porogen ratio evaluated, a column efficiency of about 6500 theoretical plates per meter was reached with a very good resolution (4.3) for very light compounds (C1-C2). The test mixture was baseline separated on a 70cm column. To our knowledge for the first time a silica-based monolithic capillary column was able to separate light hydrocarbons from methane to n-butane at room temperature with a back pressure in the range of gas chromatography facilities (under 4.1bar).

  15. SELECTIVE CATALYTIC REDUCTION (SCR OF NO BY AMMONIA OVER V2O5/TiO2 CATALYST IN A CATALYTIC FILTER MEDIUM AND HONEYCOMB REACTOR: A KINETIC MODELING STUDY

    Directory of Open Access Journals (Sweden)

    M. Nahavandi

    2015-12-01

    Full Text Available Abstract The present study addresses a numerical modeling and simulation based on the available knowledge of SCR kinetics for prediction of NO conversion over a V2O3/TiO3 catalyst through a catalytic filter medium and honeycomb reactor. After introducing the NH3-SCR system with specific operational criteria, a reactor model was developed to evaluate the effect of various operating parameters such as flue gas temperature, velocity, NH3/NO molar ratio, etc., on the SCR process. Computational investigations were performed based on the proposed model and optimum operational conditions were identified. Simulation results indicate that SCR performance is substantially under the effects of reactant concentration and operating temperature, so that the concentration of unreacted ammonia emitted from reactor discharge (ammonia slip increases significantly at NH3/NO ratios of more than 1.14 and operating temperatures less than 360 ºC and 300 ºC, respectively, in the catalytic filter medium and honeycomb reactor. The results also show that there are three sections in NO conversion variation versus changing temperature and the required conversion with a maximum of almost 87% and low level of ammonia slip can be achieved at the NH3/NO ratio of 1 and temperature range of 240–360 ºC in both reactors.

  16. Effect of process temperature on morphology of CNTs grown in a vertically fluidized bed reactor with Fe{sub 2}O{sub 3}/Al{sub 2}O{sub 3} catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Shukrullah, Shazia, E-mail: zshukrullah@gmail.com; Mohamed, Norani Muti, E-mail: noranimuti-mohamed@petronas.com.my; Shaharun, Maizatul Shima, E-mail: maizats@petronas.com.my [Department of Fundamental and Applied Sciences, Universiti Teknologi PETRONAS, 31750 Tronoh, Perak (Malaysia)

    2015-07-22

    Carbon nanotubes (CNTs) are one of the most researched materials due to their exceptional mechanical and electrical properties. Among the various techniques, catalytic chemical vapor deposition in a fluidized bed reactor is the most promising technique for bulk production of CNTs. To meet the demand of good quality along with the bulk production of CNTs, the effect of reaction temperature on the micro structures, morphology, diameter, quality and quantity of CNTs was investigated in these studies. CNTs were synthesized at process temperature ranging from 700-850°C by catalytic decomposition of C{sub 2}H{sub 4} on Fe{sub 2}O{sub 3}/Al{sub 2}O{sub 3} catalyst a vertical fluidized bed reactor. The microstructures of the grown CNTs at different reaction temperatures were investigated by using scanning electron microscope. The results of this study depicted a positive correlation between the average diameter of CNTs and reaction temperature. Narrow diameters (35∼40 nm) of CNTs with fewer defects were found at the low and mild temperatures, in particular 800°C. At this temperature, a dynamic equilibrium between the rate of C{sub 2}H{sub 4} decomposition and CNTs quantity was found due to maximum carbon diffusion over catalyst. The CNTs produced with Fe{sub 2}O{sub 3}/Al{sub 2}O{sub 3} catalyst wer e also exhibiting high quality with relatively small mean outer diameter and fewer surface defects.

  17. Epoxidation catalyst and process

    Science.gov (United States)

    Linic, Suljo; Christopher, Phillip

    2010-10-26

    Disclosed herein is a catalytic method of converting alkenes to epoxides. This method generally includes reacting alkenes with oxygen in the presence of a specific silver catalyst under conditions suitable to produce a yield of the epoxides. The specific silver catalyst is a silver nanocrystal having a plurality of surface planes, a substantial portion of which is defined by Miller indices of (100). The reaction is performed by charging a suitable reactor with this silver catalyst and then feeding the reactants to the reactor under conditions to carry out the reaction. The reaction may be performed in batch, or as a continuous process that employs a recycle of any unreacted alkenes. The specific silver catalyst has unexpectedly high selectivity for epoxide products. Consequently, this general method (and its various embodiments) will result in extraordinarily high epoxide yields heretofore unattainable.

  18. Monolithic fuel cell based power source for burst power generation

    Science.gov (United States)

    Fee, D. C.; Blackburn, P. E.; Busch, D. E.; Dees, D. W.; Dusek, J.; Easler, T. E.; Ellingson, W. A.; Flandermeyer, B. K.; Fousek, R. J.; Heiberger, J. J.

    A unique fuel cell coupled with a low power nuclear reactor presents an attractive approach for SDI burst power requirements. The monolithic fuel cell looks attractive for space applications and represents a quantum jump in fuel cell technology. Such a breakthrough in design is the enabling technology for lightweight, low volume power sources for space based pulse power systems. The monolith is unique among fuel cells in being an all solid state device. The capability for miniaturization, inherent in solid state devices, gives the low volume required for space missions. In addition, the solid oxide fuel cell technology employed in the monolith has high temperature reject heat and can be operated in either closed or open cycles. Both these features are attractive for integration into a burst power system.

  19. Fischer-Tropsch Synthesis: Influence of CO Conversion on Selectivities H2/CO Usage Ratios and Catalyst Stability for a 0.27 percent Ru 25 percent Co/Al2O3 using a Slurry Phase Reactor

    Energy Technology Data Exchange (ETDEWEB)

    W Ma; G Jacobs; Y Ji; T Bhatelia; D Bukur; S Khalid; B Davis

    2011-12-31

    The effect of CO conversion on hydrocarbon selectivities (i.e., CH{sub 4}, C{sub 5+}, olefin and paraffin), H{sub 2}/CO usage ratios, CO{sub 2} selectivity, and catalyst stability over a wide range of CO conversion (12-94%) on 0.27%Ru-25%Co/Al{sub 2}O{sub 3} catalyst was studied under the conditions of 220 C, 1.5 MPa, H{sub 2}/CO feed ratio of 2.1 and gas space velocities of 0.3-15 NL/g-cat/h in a 1-L continuously stirred tank reactor (CSTR). Catalyst samples were withdrawn from the CSTR at different CO conversion levels, and Co phases (Co, CoO) in the slurry samples were characterized by XANES, and in the case of the fresh catalysts, EXAFS as well. Ru was responsible for increasing the extent of Co reduction, thus boosting the active site density. At 1%Ru loading, EXAFS indicates that coordination of Ru at the atomic level was virtually solely with Co. It was found that the selectivities to CH{sub 4}, C{sub 5+}, and CO{sub 2} on the Co catalyst are functions of CO conversion. At high CO conversions, i.e. above 80%, CH{sub 4} selectivity experienced a change in the trend, and began to increase, and CO{sub 2} selectivity experienced a rapid increase. H{sub 2}/CO usage ratio and olefin content were found to decrease with increasing CO conversion in the range of 12-94%. The observed results are consistent with water reoxidation of Co during FTS at high conversion. XANES spectroscopy of used catalyst samples displayed spectra consistent with the presence of more CoO at higher CO conversion levels.

  20. Monolithic MACS micro resonators

    Science.gov (United States)

    Lehmann-Horn, J. A.; Jacquinot, J.-F.; Ginefri, J. C.; Bonhomme, C.; Sakellariou, D.

    2016-10-01

    Magic Angle Coil Spinning (MACS) aids improving the intrinsically low NMR sensitivity of heterogeneous microscopic samples. We report on the design and testing of a new type of monolithic 2D MACS resonators to overcome known limitations of conventional micro coils. The resonators' conductors were printed on dielectric substrate and tuned without utilizing lumped element capacitors. Self-resonance conditions have been computed by a hybrid FEM-MoM technique. Preliminary results reported here indicate robust mechanical stability, reduced eddy currents heating and negligible susceptibility effects. The gain in B1 /√{ P } is in agreement with the NMR sensitivity enhancement according to the principle of reciprocity. A sensitivity enhancement larger than 3 has been achieved in a monolithic micro resonator inside a standard 4 mm rotor at 500 MHz. These 2D resonators could offer higher performance micro-detection and ease of use of heterogeneous microscopic substances such as biomedical samples, microscopic specimens and thin film materials.

  1. The MONOLITH prototype

    CERN Document Server

    Ambrosio, M; Bencivenni, G; Candela, A M; Chiarini, A; Chignoli, F; De Deo, M; D'Incecco, M; Gerli, S; Giusti, P; Gómez, F; Gustavino, C; Lindozzi, M; Mannocchi, G; Menghetti, H; Morello, C; Murtas, F; Paoluzzi, G; Pilastrini, R; Redaelli, N G; Santoni, M; Sartorelli, G; Terranova, F; Trinchero, G C

    2000-01-01

    MONOLITH (Massive Observatory for Neutrino Oscillation or LImits on THeir existence) is the project of an experiment to study atmospheric neutrino oscillations with a massive magnetized iron detector. The baseline option is a 34 kt iron detector based on the use of about 50000 m/sup 2/ of the glass Resistive Plate Chambers (glass RPCs) developed at the Laboratori Nazionali del Gran Sasso (LNGS). An 8 ton prototype equipped with 23 m/sup 2/ of glass RPC has been realized and tested at the T7-PS beam at CERN. The energy resolution for pions follows a 68%/ square root (E(GeV))+2% law for orthogonally incident particles, in the energy range between 2 and 10 GeV. The time resolution and the tracking capability of the glass RPC are suitable for the MONOLITH experiment. (7 refs).

  2. Characterization and catalytic performance of CeO2-Co/SiO2 catalyst for Fischer-Tropsch synthesis using nitrogen-diluted synthesis gas over a laboratory scale fixed-bed reactor

    Institute of Scientific and Technical Information of China (English)

    Xiaoping Dai; Changchun Yu

    2008-01-01

    The surface species of CO hydrogenation on CeO2-Co/SiO2 catalyst were investigated using the techniques of temperature programmed reaction and transient response method. The results indicated that the formation of H2O and CO2 was the competitive reaction for the surface oxygen species, CH4 was produced via the hydrogenation of carbon species step by step, and C2 products were formed by the polymerization of surface-active carbon species (-CH2-). Hydrogen assisted the dissociation of CO. The hydrogenation of surface carbon species was the rate-limiting step in the hydrogenation of CO over CeO2-Co/SiO2 catalyst. The investigation of total pressure, gas hourly space velocity (GHSV), and product distribution using nitrogen-rich synthesis gas as feedstock over a laboratory scale fixed-bed reactor indicated that total pressure and GHSV had a significant effect on the catalytic performance of CeO2-Co/SiO2 catalyst. The removal of heat and control of the reaction temperature were extremely critical steps, which required lower GHSV and appropriate CO conversion to avoid the deactivation of the catalyst. The feedstock of nitrogen-rich synthesis gas was favorable to increase the conversion of CO, but there was a shift of product distribution toward the light hydrocarbon. The nitrogen-rich synthesis gas was feasible for F-T synthesis for the utilization of remote natural gas.

  3. 甲烷无氧芳构化反应器及催化剂积炭的研究进展%Process in Reactor and Catalyst Coke of Methane Dehydroaromatization Under the Condition of Oxyger Free

    Institute of Scientific and Technical Information of China (English)

    袁钊; 陆江银

    2012-01-01

    Concluded the research progress of non - oxidative aromatization of methane on the reaction mechanism, the choice of reactor and catalysts, catalyst coke and regeneration, which were significant in the fields of process development , energy utilization and catalysis science.%综述了甲烷无氧芳构化反应的研究进展,对甲烷无氧芳构化反应机理、反应器的选择、催化剂的选择、催化剂积炭失活与再生等方面做了讨论,对甲烷无氧芳构化的工艺开发、对能源利用、催化科学均具有重大意义。

  4. Membrane reactor. Membrane reactor

    Energy Technology Data Exchange (ETDEWEB)

    Shindo, Y.; Wakabayashi, K. (National Chemical Laboratory for Industry, Tsukuba (Japan))

    1990-08-05

    Many reaction examples were introduced of membrane reactor, to be on the point of forming a new region in the field of chemical technology. It is a reactor to exhibit excellent function, by its being installed with membrane therein, and is generally classified into catalyst function type and reaction promotion type. What firstly belongs to the former is stabilized zirconia, where oxygen, supplied to the cathodic side of membrane with voltage, impressed thereon, becomes O {sup 2 {minus}} to be diffused through the membrane and supplied, as variously activated oxygenous species, on the anodic side. Examples with many advantages can be given such as methane coupling, propylene oxidation, methanating reaction of carbon dioxide, etc. Apart, palladium film and naphion film also belong to the former. While examples of the latter comprise, among others, decomposition of hydrogen sulfide by porous glass film and dehydrogenation of cyclohexane or palladium alloy film, which are expected to be developed and materialized in the industry. 33 refs., 8 figs.

  5. Promotional effects of Titanium additive on the surface properties, active sites and catalytic activity of W/CeZrOx monolithic catalyst for the selective catalytic reduction of NOx with NH3

    Science.gov (United States)

    Xu, Haidi; Feng, Xi; Liu, Shuang; Wang, Yun; Sun, Mengmeng; Wang, Jianli; Chen, Yaoqiang

    2017-10-01

    CeZrTixO2 mixed oxides were prepared by a co-precipitation method, and serial WO3/CeZrTixO2 catalysts were prepared to investigate the influence of doping TiO2 into CeZrO2 on the catalytic performance of selective catalytic reduction of NOx with NH3. The activity results showed that the introduction of appropriate amount of TiO2 could effectively improve the catalytic performance. WO3/CeZrTi20O2 with 20 wt.% TiO2 showed better deNOx activity and sulfur/water vapor tolerance than W/CeZrO2. Several techniques, including N2 physisorption, XRD, XPS, H2-TPR, NH3-TPD and in situ DRIFTS, were employed to characterize catalysts. The results indicated that doping TiO2 led to the formation of cerium-zirconium-titanium solid solution with larger surface area. The interactions among metal oxides could enhance the redox properties of the catalyst, which was helpful to the improvement of the low-temperature NH3-SCR activity. Moreover, the addition of TiO2 promoted the adsorption and activation of NH3 and increased the reactivity of adsorbed nitrate species with NH3 species, which significantly affected the NH3-SCR performance. Finally, the results of in situ DRIFTS demonstrated that the NH3-SCR reaction mainly followed the Langmuir-Hinshelwood mechanism over W/CeZrO2 and W/CeZrTi20O2 catalysts at 200 °C.

  6. Effect of Fe2O3 Loading Amount on Catalytic Properties of Monolithic Fe2O3/Ce0.67Zr0.33O2-Al2O3 Catalyst for Methane Combustion

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Ce0.67Zr0.33O2-Al2O3 solid solution was prepared by the co-precipitation method. Fe2O3-based catalysts supported on the solid solution were obtained by the impregnation method. The article revealed that the optimal loading amount of Fe2O3 on Ce0.67Zr0.33O2-Al2O3 in our experimental condition for catalytic combustion of methane was 8%( mass fraction). The prepared catalysts were characterized by BET, TPR, XRD analyses, and their catalytic activity was investigated after being calcined at 873 K and after being aged in water gas at 1273 K. When the loading amount of Fe2O3 was 8%( mass fraction), the catalyst held the highest activity, and the best temperature speciality and thermal stability. The complete-conversion temperature of methane for fresh and aged sample was 788 and 838 K, respectively. The range between the light-off temperature and the complete-conversion temperature was only 15 K. The characterization results of XRD indicated that Fe2O3 was well dispersed on the Ce0.67Zr0.33O2-Al2O3 matrix. The results of BET and TPR were in good harmony with the catalytic activity results.

  7. Session 4: Atr catalyst for natural gas conversion to hydrogen: performance, simulation, and modeling

    Energy Technology Data Exchange (ETDEWEB)

    Baumann, F.; Duisberg, M.; Sextl, G.; Wieland, S. [Umicore AG and Co. KG, Hanau (Germany); Deutschmann, O. [Karlsruhe Univ., Institute for Chemical Technology (Germany); Maier, L. [Heidelberg Univ., IWR (Germany); Schmidt, L.D. [Minnesota Univ., Chem. Engineering and Mat. Sciences Minneapolis (United States)

    2004-07-01

    A non-pyrophoric precious metal based auto-thermal reforming catalyst was developed and, the performance of the catalyst at different operational conditions was measured. Additionally, the physical properties of the catalytic layer such as precious metal loading, the BET surface, and the dispersion were determined. A profound knowledge of the ATR process is required to improve the performance of the catalyst. Therefore, a detailed reaction mechanism consisting of 42 reactions among six stable gas-phase and further 23 adsorbed species was developed for the simultaneous description of the partial oxidation, heated steam reforming, water-gas shift reactions and the undesired methanation. A variety of numerical simulations of the ATR process at various conditions were performed using the CFD code DETCHEM(CHANNEL), which models the flow field in monolithic channels and the chemical processes in the gas phase and on the surface including diffusion and reactions in the wash coat structure. The results demonstrate the applicability of the developed mechanism for Umicore's ATR catalyst. The simulation offers an insight into the processes occurring in the catalytic reactor. The figure, for instance, reveals the surface coverage of the reacting species along the catalytic channel wall. In the first centimetre of the catalyst the concentrations vary drastically. The initially high oxygen coverage, leading to total oxidation and heat release, decreases rapidly. Farther downstream the processes on the catalyst are predominated by steam reforming; oxygen on the surface now comes from re-adsorbed water. Thus, the verified model allows the localization of different reaction zones. This information can be generated for different operation conditions such as start up or load alternation. Thus the model is a valuable tool for further improvement of the catalyst performance by 'designing' new formulations. (authors)

  8. Comparison of real waste (MSW and MPW) pyrolysis in batch reactor over different catalysts. Part II: contaminants, char and pyrolysis oil properties.

    Science.gov (United States)

    Miskolczi, Norbert; Ateş, Funda; Borsodi, Nikolett

    2013-09-01

    Pyrolysis of real wastes (MPW and MSW) has been investigated at 500°C, 550°C and 600°C using Y-zeolite, β-zeolite, equilibrium FCC, MoO3, Ni-Mo-catalyst, HZSM-5 and Al(OH)3 as catalysts. The viscosity of pyrolysis oils could be decreased by the using of catalysts, especially by β-zeolite and MoO3. Both carbon frame and double bound isomerization was found in case of thermo-catalytic pyrolysis. Char morphology and texture analysis showed more coke deposits on the catalyst surface using MSW raw material. Pyrolysis oils had K, S, P Cl, Ca, Zn, Fe, Cr, Br and Sb as contaminants; and the concentrations of K, S, P, Cl and Br could be decreased by the using of catalysts.

  9. Bioaffinity chromatography on monolithic supports

    NARCIS (Netherlands)

    Tetala, K.K.R.; Beek, van T.A.

    2010-01-01

    Affinity chromatography on monolithic supports is a powerful analytical chemical platform because it allows for fast analyses, small sample volumes, strong enrichment of trace biomarkers and applications in microchips. In this review, the recent research using monolithic materials in the field of bi

  10. Bioaffinity chromatography on monolithic supports

    NARCIS (Netherlands)

    Tetala, K.K.R.; Beek, van T.A.

    2010-01-01

    Affinity chromatography on monolithic supports is a powerful analytical chemical platform because it allows for fast analyses, small sample volumes, strong enrichment of trace biomarkers and applications in microchips. In this review, the recent research using monolithic materials in the field of bi

  11. Recent advances in the preparation and application of monolithic capillary columns in separation science

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Tingting; Yang, Xi; Xu, Yujing [Department of Analytical Chemistry, China Pharmaceutical University, Nanjing, 210009 (China); Key Laboratory of Drug Quality Control and Pharmacovigilance, Ministry of Education, Nanjing, 210009 (China); Ji, Yibing, E-mail: jiyibing@msn.com [Department of Analytical Chemistry, China Pharmaceutical University, Nanjing, 210009 (China); Key Laboratory of Drug Quality Control and Pharmacovigilance, Ministry of Education, Nanjing, 210009 (China)

    2016-08-10

    Novel column technologies involving various materials and efficient reactions have been investigated for the fabrication of monolithic capillary columns in the field of analytical chemistry. In addition to the development of these miniaturized systems, a variety of microscale separation applications have achieved noteworthy results, providing a stepping stone for new types of chromatographic columns with improved efficiency and selectivity. Three novel strategies for the preparation of capillary monoliths, including ionic liquid-based approaches, nanoparticle-based approaches and “click chemistry”, are highlighted in this review. Furthermore, we present the employment of state-of-the-art capillary monolithic stationary phases for enantioseparation, solid-phase microextraction, mixed-mode separation and immobilized enzyme reactors. The review concludes with recommendations for future studies and improvements in this field of research. - Highlights: • Preparation of novel monolithic capillary columns have shown powerful potential in analytical chemistry field. • Various materials including ionic liquids and nanoparticles involved into capillary monolithic micro-devices are concluded. • Click chemistry strategy applied for preparing monolithic capillary columns is reviewed. • Recent strategies utilized in constructing different capillary monoliths for enantiomeric separation are summarized. • Advancement of capillary monoliths for complex samples analysis is comprehensively described.

  12. Design of monoliths through their mechanical properties.

    Science.gov (United States)

    Podgornik, Aleš; Savnik, Aleš; Jančar, Janez; Krajnc, Nika Lendero

    2014-03-14

    Chromatographic monoliths have several interesting properties making them attractive supports for analytics but also for purification, especially of large biomolecules and bioassemblies. Although many of monolith features were thoroughly investigated, there is no data available to predict how monolith mechanical properties affect its chromatographic performance. In this work, we investigated the effect of porosity, pore size and chemical modification on methacrylate monolith compression modulus. While a linear correlation between pore size and compression modulus was found, the effect of porosity was highly exponential. Through these correlations it was concluded that chemical modification affects monolith porosity without changing the monolith skeleton integrity. Mathematical model to describe the change of monolith permeability as a function of monolith compression modulus was derived and successfully validated for monoliths of different geometries and pore sizes. It enables the prediction of pressure drop increase due to monolith compressibility for any monolith structural characteristics, such as geometry, porosity, pore size or mobile phase properties like viscosity or flow rate, based solely on the data of compression modulus and structural data of non-compressed monolith. Furthermore, it enables simple determination of monolith pore size at which monolith compressibility is the smallest and the most robust performance is expected. Data of monolith compression modulus in combination with developed mathematical model can therefore be used for the prediction of monolith permeability during its implementation but also to accelerate the design of novel chromatographic monoliths with desired hydrodynamic properties for particular application.

  13. Ce-Zr-La/Al2O3 prepared in a continuous stirred-tank reactor: a highly thermostable support for an efficient Rh-based three-way catalyst.

    Science.gov (United States)

    Wang, Su-Ning; Lan, Li; Hua, Wei-Bo; Shi, Zhong-Hua; Chen, Yao-Qiang; Gong, Mao-Chu; Zhong, Lin

    2015-12-21

    Two Ce-Zr-La/Al2O3 composite oxides, CZLA-C and CZLA-B, were synthesized using a co-precipitation method in a continuous stirred-tank reactor (CSTR) and a batch reactor (BR), respectively. Two Rh-based three-way catalysts (TWCs), Rh/CZLA-C and Rh/CZLA-B were obtained by a wet-impregnation method using the two composites as the supports. The physicochemical properties of the samples before and after thermal treatment at 1000 °C were characterized by N2 adsorption-desorption, X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), H2-temperature programmed reduction (H2-TPR) and CO chemisorption. The results indicated that CZLA-C shows higher thermal stability than CZLA-B due to a sparsely-agglomerated morphology. Compared with Rh/CZLA-B, Rh/CZLA-C displayed better reducibility and higher thermal stability and exhibited significantly higher activity in the catalytic removal of the simulated gasoline vehicle exhaust emission (NO, CO and C3H8). Our work can provide a facile and economical synthesis route to advanced support materials and catalysts for exhaust emission control.

  14. Porous polymer monolithic col

    Directory of Open Access Journals (Sweden)

    Lydia Terborg

    2015-05-01

    Full Text Available A new approach has been developed for the preparation of mixed-mode stationary phases to separate proteins. The pore surface of monolithic poly(glycidyl methacrylate-co-ethylene dimethacrylate capillary columns was functionalized with thiols and coated with gold nanoparticles. The final mixed mode surface chemistry was formed by attaching, in a single step, alkanethiols, mercaptoalkanoic acids, and their mixtures on the free surface of attached gold nanoparticles. Use of these mixtures allowed fine tuning of the hydrophobic/hydrophilic balance. The amount of attached gold nanoparticles according to thermal gravimetric analysis was 44.8 wt.%. This value together with results of frontal elution enabled calculation of surface coverage with the alkanethiol and mercaptoalkanoic acid ligands. Interestingly, alkanethiols coverage in a range of 4.46–4.51 molecules/nm2 significantly exceeded that of mercaptoalkanoic acids with 2.39–2.45 molecules/nm2. The mixed mode character of these monolithic stationary phases was for the first time demonstrated in the separations of proteins that could be achieved in the same column using gradient elution conditions typical of reverse phase (using gradient of acetonitrile in water and ion exchange chromatographic modes (applying gradient of salt in water, respectively.

  15. 浸渍法制备的Pd-MnOx/γ-Al2O3催化剂及不同载体对地表O3降解的影响%Pd-MnOx/γ-Al2O3 Monolithic Catalysts Prepared by Impregnation Method and Effect of Different Supports on Ground-Level Ozone Decomposition

    Institute of Scientific and Technical Information of China (English)

    任成军; 周丽娜; 尚鸿燕; 陈耀强

    2014-01-01

    在γ-Al2O3载体上用等体积浸渍法浸渍Pd、MnOx活性组分,然后涂覆于堇青石基体上制备Pd-MnOx/γ-Al2O3整体式催化剂.分别用 X 射线衍射(XRD)、H2-程序升温还原(H2-TPR)、低温 N2吸附-脱附及 X 射线光电子能谱(XPS)对制备的催化剂进行表征.研究了Pd、MnOx浸渍顺序对催化剂活性、氧化还原性能及织构性质的影响.实验结果表明, Pd、MnOx共浸渍较分别浸渍制备的催化剂活性好, Pd 和 MnOx之间存在一定的协同作用.考察了不同载体如La-Al2O3、SiO2、γ-Al2O3和Zr-Al2O3对催化剂活性、氧化还原性能、织构性质及表面电子性能的影响.研究表明,以La-Al2O3或SiO2为载体的催化剂活性最好,即,14°C时O3转化率为82%,完全转化温度为36°C.γ-Al2O3载体次之, Zr-Al2O3载体较差.不同载体制备的催化剂中 MnOx的氧化还原性能顺序为: Pd-MnOx/SiO2>Pd-MnOx/La-Al2O3>Pd-MnOx/γ-Al2O3>Pd-MnOx/Zr-Al2O3.%Pd-MnOx/γ-Al2O3 catalysts were prepared by impregnating Pd and MnOx on γ-Al2O3 supports, using an incipient wetness impregnation method, and then coating on a cordierite substrate to obtain monolithic catalysts. The catalysts were characterized using X-ray diffraction (XRD), temperature-programmed reduction of H2 (H2-TPR), low-temperature N2 adsorption-desorption measurements, and X-ray photoelectron spectroscopy (XPS). The effects of the Pd and MnOx impregnation order on the catalytic activity, redox performance, textural properties, and surface electronic characteristics of the catalysts were studied. The experimental results showed that the activity of the catalyst co-impregnated with Pd and MnOx on γ-Al2O3 was better than that of the catalyst impregnated sequentially with Pd and MnOx. A synergetic effect was observed between Pd and MnOx on the Pd-MnOx/γ-Al2O3 catalysts for ozone decomposition. The effects of various supports on catalytic activity, redox performance, textural properties, and surface electron

  16. Catalyst for reduction of nitrogen oxides

    Science.gov (United States)

    Ott, Kevin C.

    2010-04-06

    A Selective Catalytic Reduction (SCR) catalyst was prepared by slurry coating ZSM-5 zeolite onto a cordierite monolith, then subliming an iron salt onto the zeolite, calcining the monolith, and then dipping the monolith either into an aqueous solution of manganese nitrate and cerium nitrate and then calcining, or by similar treatment with separate solutions of manganese nitrate and cerium nitrate. The supported catalyst containing iron, manganese, and cerium showed 80 percent conversion at 113 degrees Celsius of a feed gas containing nitrogen oxides having 4 parts NO to one part NO.sub.2, about one equivalent ammonia, and excess oxygen; conversion improved to 94 percent at 147 degrees Celsius. N.sub.2O was not detected (detection limit: 0.6 percent N.sub.2O).

  17. Biobased monoliths for adenovirus purification.

    Science.gov (United States)

    Fernandes, Cláudia S M; Gonçalves, Bianca; Sousa, Margarida; Martins, Duarte L; Barroso, Telma; Pina, Ana Sofia; Peixoto, Cristina; Aguiar-Ricardo, Ana; Roque, A Cecília A

    2015-04-01

    Adenoviruses are important platforms for vaccine development and vectors for gene therapy, increasing the demand for high titers of purified viral preparations. Monoliths are macroporous supports regarded as ideal for the purification of macromolecular complexes, including viral particles. Although common monoliths are based on synthetic polymers as methacrylates, we explored the potential of biopolymers processed by clean technologies to produce monoliths for adenovirus purification. Such an approach enables the development of disposable and biodegradable matrices for bioprocessing. A total of 20 monoliths were produced from different biopolymers (chitosan, agarose, and dextran), employing two distinct temperatures during the freezing process (-20 °C and -80 °C). The morphological and physical properties of the structures were thoroughly characterized. The monoliths presenting higher robustness and permeability rates were further analyzed for the nonspecific binding of Adenovirus serotype 5 (Ad5) preparations. The matrices presenting lower nonspecific Ad5 binding were further functionalized with quaternary amine anion-exchange ligand glycidyltrimethylammonium chloride hydrochloride by two distinct methods, and their performance toward Ad5 purification was assessed. The monolith composed of chitosan and poly(vinyl) alcohol (50:50) prepared at -80 °C allowed 100% recovery of Ad5 particles bound to the support. This is the first report of the successful purification of adenovirus using monoliths obtained from biopolymers processed by clean technologies.

  18. A monolithic integrated micro direct methanol fuel cell based on sulfo functionalized porous silicon

    Science.gov (United States)

    Wang, M.; Lu, Y. X.; Liu, L. T.; Wang, X. H.

    2016-11-01

    In this paper, we demonstrate a monolithic integrated micro direct methanol fuel cell (μDMFC) for the first time. The monolithic integrated μDMFC combines proton exchange membrane (PEM) and Pt nanocatalysts, in which PEM is achieved by the functionalized porous silicon membrane and 3D Pt nanoflowers being synthesized in situ on it as catalysts. Sulfo groups functionalized porous silicon membrane serves as a PEM and a catalyst support simultaneously. The μDMFC prototype achieves an open circuit voltage of 0.3 V, a maximum power density of 5.5 mW/cm2. The monolithic integrated μDMFC offers several desirable features such as compatibility with micro fabrication techniques, an undeformable solid PEM and the convenience of assembly.

  19. Effect on mass transference phenomena by textural change inside monolithic carbon aerogels

    Science.gov (United States)

    Chejne, F.; Camargo-Trillos, D.; Pabón, E.; Carrasco-Marin, F.

    2015-08-01

    The effects on mass transference phenomena due textural changes of monolithic carbon aerogels were studied by hexane adsorption. The monolithic carbon aerogels were prepared after carbonization of the organic aerogels obtained by resorcinol-formaldehyde polymerization, using p-toluenesulfonic acid (acid-catalyst) and sodium carbonate catalysts (basic-catalyst). Internal texture was modified by CO2 activation. The characterization by gas adsorption showed that the monolithic carbon aerogels presents a bi-modal pore size distribution with presence of both microporous and mesoporous. It was shown that the activation process of monolithic carbon aerogels increases their micropore volume bigger than the other one acid-catalyst aerogel. The mesopores volume in the carbon aerogels plays an important role on mass transport mechanism. The samples with presence of significant mesopore volume present a lower height of mass transfer zone than others less mesopore volume; therefore better efficiency of adsorption in mass transfer zone in dynamic adsorption. The breakthrough curve methodology proposed in this work has allowed finding a relationship between the structural parameters and dynamic adsorption variables, which opens new approaches for measuring textural parameters of material.

  20. Monolithic microchannel heatsink

    Science.gov (United States)

    Benett, William J.; Beach, Raymond J.; Ciarlo, Dino R.

    1996-01-01

    A silicon wafer has slots sawn in it that allow diode laser bars to be mounted in contact with the silicon. Microchannels are etched into the back of the wafer to provide cooling of the diode bars. To facilitate getting the channels close to the diode bars, the channels are rotated from an angle perpendicular to the diode bars which allows increased penetration between the mounted diode bars. This invention enables the fabrication of monolithic silicon microchannel heatsinks for laser diodes. The heatsinks have low thermal resistance because of the close proximity of the microchannels to the laser diode being cooled. This allows high average power operation of two-dimensional laser diode arrays that have a high density of laser diode bars and therefore high optical power density.

  1. Oxidation catalyst

    Science.gov (United States)

    Ceyer, Sylvia T.; Lahr, David L.

    2010-11-09

    The present invention generally relates to catalyst systems and methods for oxidation of carbon monoxide. The invention involves catalyst compositions which may be advantageously altered by, for example, modification of the catalyst surface to enhance catalyst performance. Catalyst systems of the present invention may be capable of performing the oxidation of carbon monoxide at relatively lower temperatures (e.g., 200 K and below) and at relatively higher reaction rates than known catalysts. Additionally, catalyst systems disclosed herein may be substantially lower in cost than current commercial catalysts. Such catalyst systems may be useful in, for example, catalytic converters, fuel cells, sensors, and the like.

  2. Hierarchically structured monolithic silicalite-1 consisting of crystallized nanoparticles and its performance in the Beckmann rearrangement of cyclohexanone oxime.

    Science.gov (United States)

    Li, Wen-Cui; Lu, An-Hui; Palkovits, Regina; Schmidt, Wolfgang; Spliethoff, Bernd; Schüth, Ferdi

    2005-09-14

    In this study, we present a synthetic pathway for the fabrication of self-supporting zeolite monoliths consisting of crystallized nanoparticles. A resorcinol-formaldehyde-based organic aerogel is used as a template, and silicalite-1 is used as the zeolite example. The silicalite-1 monoliths obtained consist of individual well-defined zeolite nanocrystals with sizes of 30-40 nm. The monoliths exhibit a high mechanical stability and have hierarchical porosity, with micropores within the zeolite particles, a mesopore system formed by the packing of the nanoparticles, and a macropore system on the monolith level. Such monolithic zeolites show high selectivity typically above 80% to epsilon-caprolactam combined with a high rate of reaction of 0.46 g(caprolactame)/(g(catalyst).h) in the Beckmann rearrangement of cyclohexanone oxime.

  3. Nuclear Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Hogerton, John

    1964-01-01

    This pamphlet describes how reactors work; discusses reactor design; describes research, teaching, and materials testing reactors; production reactors; reactors for electric power generation; reactors for supply heat; reactors for propulsion; reactors for space; reactor safety; and reactors of tomorrow. The appendix discusses characteristics of U.S. civilian power reactor concepts and lists some of the U.S. reactor power projects, with location, type, capacity, owner, and startup date.

  4. Research on Si-Al based catalysts prepared by complete liquid-phase method for DME synthesis in a slurry reactor

    Science.gov (United States)

    Li, Zhihong; Zuo, Zhijun; Huang, Wei; Xie, Kechang

    2011-01-01

    A series of Si-Al based DME synthesis catalysts were prepared by complete liquid-phase method and characterized by in situ XPS, XRD, N 2 adsorption and NH 3-TPD analyses. Based on the results, the addition of Si could adjust the pore structure and surface acidity of catalyst, exhibiting a strong promoting effect on the CO conversion and DME selectivity. However, when Si/Al ratio is higher, Si would cover active sites and increase the amount of strong acidity sites, causing the reduction in catalytic activity. It was found from in situ XPS characterization that Cu 0 is the active center of methanol synthesis in DME production, and the addition of Si changes the chemical surroundings of active components and weaken the interaction between Cu, Zn and Al, which maybe give rise to the decrease in catalyst stability.

  5. Synthesis of novel hierarchical ZSM-5 monoliths and their application in trichloroethylene removal

    Institute of Scientific and Technical Information of China (English)

    João Pires; Ana C.Fernandes; Divakar Duraiswami

    2014-01-01

    A self-supporting ZSM-5 monolith with a hierarchical porosity was prepared using polyurethane foam (PUF) as a structural template and a hydrothermal synthesis procedure. The synthesized monolith was characterized and investigated towards the adsorption and catalytic oxidation of trichloroethylene (TCE). Adsorption of TCE was studied gravimetrically and oxidation of TCE was studied using a vapor-phase down-flow reactor. Monolithic ZSM-5 displayed good sorption proper-ties and completely oxidized TCE. Conversion levels of 50%and 90%were achieved at reduced temperatures (by~50 °C) when compared with the conversion temperatures obtained from the powder counterparts. Besides the activity of the monolith towards TCE adsorption and oxidation, it was stable and enhanced diffusion, thereby reducing pressure drops to a great extent owing to its hierarchical porous nature.

  6. Removal of Cooking Fume by Catalytic Combustion on Pt/La-Al2O3 + Ce0.5Zr0.5O2 Catalyst

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Four monolithic catalysts with low concentration of noble metal were prepared by the immersion method [ Pt/LaAl2O3, Pt/La-Al2O3 + Pt/OSM (2∶1), Pt/La-Al2O3 + Pt/OSM (1∶1) Pt/La-Al2O3 + Pt/OSM (1∶2)], and measurements of their activity were carried out in a conventional fixed-bed flow reactor. The results show that the oxygen storage material (OSM) that is added can promote the activity of the prepared catalysts and can decrease the complete conversion temperature of cooking fume. When the ratio between La-Al2O3 and OSM is 1∶ 1, the catalyst has the highest activity, and the complete conversion temperature of cooking fume is 270 ℃; the catalyst thus prepared can be applied in a wide range of gas hourly space velocity (GHSV) [from 10000 to 60000 h-1 ]. The catalyst obtained shows great potential for practical application.

  7. A low-temperature co-fired ceramic micro-reactor system for high-efficiency on-site hydrogen production

    Science.gov (United States)

    Jiang, Bo; Maeder, Thomas; Santis-Alvarez, Alejandro J.; Poulikakos, Dimos; Muralt, Paul

    2015-01-01

    A ceramic-based, meso-scale fuel processor for on-board production of syngas fuel was demonstrated for applications in micro-scale solid-oxide fuel cells (μ-SOFCs). The processor had a total dimension of 12 mm × 40 mm × 2 mm, the gas reforming micro reactor occupying the hot end of a cantilever had outer dimensions of 12 × 18 mm. The device was fabricated through a novel progressive lamination process in low-temperature co-fired ceramic (LTCC) technology. Both, heating function and desired fluidic structures were integrated monolithically into the processor. Using catalytic partial oxidation of a hydrocarbon fuel (propane) as a reaction model, a thermally self-sustaining hydrogen production was achieved. The output flow is sufficiently high to drive an optimized single membrane μSOFC cell of about the same footprint as the micro reactor. Microsystem design, fabrication, catalyst integration as well as the chemical characterization are discussed in detail.

  8. Reprocessing of LEU U-Mo Dispersion and Monolithic Fuels

    Energy Technology Data Exchange (ETDEWEB)

    Vandegrift, G.F.; Jerden, J.; Stepinski, D.C.; Figueroa, J.; Williamson, M.A.; Kleeck, M.A. Van; Blaskovitz, R.J.; Ziegler, A.J.; Maggos, L.E.; Swanson, J.; Fortner, J.; Bakel, A.J. [Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 S. Cass Ave., Argonne, IL 60439 (United States)

    2011-07-01

    For conversion of high-performance research reactors from high-enriched uranium (HEU) to low-enriched uranium (LEU) fuel, a fuel material with a higher density than uranium aluminide is required. Development studies are underway to develop U-Mo dispersion and monolithic fuels for conversion of several high- performance reactors. For dispersion fuels, development is narrowing down to a composition of U-7Mo dispersed in an aluminium matrix containing {approx}5% silicon. For monolithic fuels to be used in high performance research reactors in the United States, a zirconium-bonded U-10Mo foil appears to be the fuel of choice. For conversion to be realized a back-end disposition path is required for both fuels; one disposition pathway is reprocessing. Argonne National Laboratory is developing a pyroprocess for reprocessing spent monolithic fuel. Pyroprocessing was chosen over conventional aqueous solvent extraction due to the necessity of adding fluoride to the fuel-dissolution solution in order to dissolve the zirconium bonding layer on the U-Mo fuel. The proposed flowsheet and development activities will be described. A literature survey points to the ability to reprocess U-Mo dispersion fuels by an aqueous process, but due to several special characteristics of the fuel, the solvent-extraction flowsheets will be a departure from that normally used for the reprocessing of power reactor fuel. Special concerns that must be addressed in reprocessing these fuels are, for example, the low solubilities of uranyl molybdate, molybdic acid, and silicic acid in nitric acid solutions. This paper will address these concerns and development activities required to overcome them. (author)

  9. Single Pellet String Reactor for Intensification of Catalyst Testing in Gas/Liquid/Solid Configuration Réacteur catalytique de type “filaire” pour l’intensification de tests catalytiques en configuration gaz/liquide/solide

    Directory of Open Access Journals (Sweden)

    Hipolito A.I.

    2010-09-01

    Full Text Available Catalyst improvement is a key route toward process improvement in terms of yield, energy efficiency and selectivity optimization. The catalyst development strategy includes catalyst testing on a model or real feedstock. This key step has been the focus of many studies during the last decades concerning reactor design, analytical tool development and operating procedures. Most studies aim to determine catalytic grain activity in isothermal conditions so as to be able to understand and predict the kinetics. With catalyst improvement, in the lab-scale reactors available, the mass transfer rate can become the limiting step compared with the reaction rate, especially for fast exothermic reactions. A new reactor geometry is proposed to intensify the mass transfer and to accelerate the fluid superficial velocities: the single pellet string reactor. To characterize this new geometry, a hydrodynamic study was carried out in a horizontal single pellet string reactor with a 4.0 × 4.0 mm2 square section, filled with spherical particles of diameter varying between 2.0 and 4.0 mm. In this hydrodynamic study, visual observations of the flow patterns were performed, as well as pressure drop measurements and residence time distribution analysis in single liquid phase flow and two-phase flows. In every configuration tested, two main regimes were identified: the “isolated bubbles” regime and the “stratified” regime. Peclet number and liquid hold-up were deduced from the residence time distribution analysis. The measured liquid hold-ups are always higher than 0.6, which indicates, in addition to the visual observations and colorimetric tests, that the catalyst is always fully wetted by the liquid film. The axial dispersion measurements showed that the single liquid phase flow cannot be interpreted by a classical axial dispersion model. However, when a gas phase is added, the flow becomes closer to plug flow, with Peclet numbers always higher than 40. It

  10. Monolithic Laser Scribed Graphene Scaffold with Atomic Layer Deposited Platinum for Hydrogen Evolution Reaction

    KAUST Repository

    Nayak, Pranati

    2017-09-01

    The use of three-dimensional (3D) electrode architectures as scaffolds for conformal deposition of catalysts is an emerging research area with significant potential for electrocatalytic applications. In this study, we report the fabrication of monolithic, self-standing, 3D graphitic carbon scaffold with conformally deposited Pt by atomic layer deposition (ALD) as a hydrogen evolution reaction catalyst. Laser scribing is employed to transform polyimide into 3D porous graphitic carbon, which possesses good electronic conductivity and numerous edge plane sites. This laser scribed graphene (LSG) architecture makes it possible to fabricate monolithic electrocatalyst support without any binders or conductive additives. The synergistic effect between ALD of Pt on 3D network of LSG provides an avenue for minimal yet effective Pt usage, leading to an enhanced HER activity. This strategy establish a general approach for inexpensive and large scale HER device fabrication with minimum catalyst cost.

  11. Growth of single-walled carbon nanotubes on a Co-Mo-MgO supported catalyst by the CVD of methane in a fixed bed reactor: Model setting and parameter estimation

    Science.gov (United States)

    Izadi, Nosrat; Rashidi, Ali Morad; Horri, Bahman Amini; Mosoudi, Mohamad Reza; Bozorgzadeh, Hamid Reza; Zeraatkar, Ahmad

    2011-06-01

    In this work methane was decomposed to hydrogen and carbon to determine its kinetic behavior during reaction over a Co-Mo-MgO supported catalyst using the CVD (Chemical Vapor Deposition) technique. Decomposition of methane molecules was performed in a continuous fixed bed reactor to obtain data to simulate methane decomposition in a gas phase heterogeneous media. The products and reactants of reaction were analyzed by molecular sieve column followed by GC-analysis of the fractions to determine the amount of product converted or reactant consumed. The synthesis of single-walled carbon nanotubes was performed at atmospheric pressure, different temperatures and reactant concentrations. The experimental data analyzed to suggest the formula for calculation of the initial specific reaction rate of the carbon nanotubes synthesis, were fitted by several mathematical models derived from different mechanisms based on Longmuir-hinshelwood expression. The suggested mechanism according to dissociation adsorption of methane seems to explain the catalytic performance in the range of operating conditions studied. The apparent activation energy for the growth of SWNTs was estimated according to Arrhenius equation. The as grown SWNTs products were characterized by SEM, TEM and Raman spectroscopy after purification. The catalyst deactivation was found to be dependent on the time, reaction temperature and partial pressure of methane and indicated that the reaction of deactivation can be modeled by a simple apparent second order of reaction.

  12. A novel carbon fiber based porous carbon monolith

    Energy Technology Data Exchange (ETDEWEB)

    Burchell, T.D.; Klett, J.W.; Weaver, C.E.

    1995-06-01

    A novel porous carbon material based on carbon fibers has been developed. The material, when activated, develops a significant micro- or mesopore volume dependent upon the carbon fiber type utilized (isotropic pitch or polyacrylonitrile). The materials will find applications in the field of fluid separations or as a catalyst support. Here, the manufacture and characterization of our porous carbon monoliths are described. A novel adsorbent carbon composite material has been developed comprising carbon fibers and a binder. The material, called carbon fiber composite molecular sieve (CFCMS), was developed through a joint research program between Oak Ridge National Laboratory (ORNL) and the University of Kentucky, Center for Applied Energy Research (UKCAER).

  13. Chromatographic and Related Reactors.

    Science.gov (United States)

    1988-01-07

    special information about effects of surface heteroge- neity in the methanation reaction. Studies of an efficient multicolumn assembly for measuring...of organic basic catalysts such as pyridine and 4-methylpicoline. It was demonstrated that the chromatographic reactor gave special information about...Programmed Reaction to obtain special information about surface heterogeneity in the methanation reaction. Advantages of stopped flow over steady state

  14. Fabrication of Monolithic RERTR Fuels by Hot Isostatic Pressing

    Energy Technology Data Exchange (ETDEWEB)

    Jan-Fong Jue; Blair H. Park; Curtis R. Clark; Glenn A. Moore; Dennis D. Keiser, Jr.

    2010-11-01

    The RERTR (Reduced Enrichment for Research and Test Reactors) Program is developing advanced nuclear fuels for high-power test reactors. Monolithic fuel design provides higher uranium loading than that of the traditional dispersion fuel design. Hot isostatic pressing is a promising process for low-cost batch fabrication of monolithic RERTR fuel plates for these high-power reactors. Bonding U Mo fuel foil and 6061 Al cladding by hot isostatic press bonding was successfully developed at Idaho National Laboratory. Due to the relatively high processing temperature, the interaction between fuel meat and aluminum cladding is a concern. Two different methods were employed to mitigate this effect: (1) a diffusion barrier and (2) a doping addition to the interface. Both types of fuel plates have been fabricated by hot isostatic press bonding. Preliminary results show that the direct fuel/cladding interaction during the bonding process was eliminated by introducing a thin zirconium diffusion barrier layer between the fuel and the cladding. Fuel plates were also produced and characterized with a silicon-rich interlayer between fuel and cladding. This paper reports the recent progress of this developmental effort and identifies the areas that need further attention.

  15. MECHANICAL STRENGTH AND RELIABILITY OF SOLID CATALYSTS

    Institute of Scientific and Technical Information of China (English)

    Yongdan Li; Dongfang Wu; Y.S. Lin

    2004-01-01

    The mechanical strength of solid catalysts is one of the key parameters for reliable and efficient performance of a fixed bed reactor. Some recent developments and their basic mechanics within this context are reviewed. The main concepts discussed are brittle fracture which leads to the mechanical failure of the catalyst pellets, measurement and statistical properties of the catalyst strength data, and mechanical reliability of the catalyst pellets and their packed bed. The scientific basis for the issues on the catalyst mechanical properties calls yet for further elucidation and advancement.

  16. Modeling Open-Flow Steam Reforming of Methanol over Cu/ZnO/Al2O3 Catalyst in an Axisymmetric Reactor

    Directory of Open Access Journals (Sweden)

    Leonardo Pacheco

    2015-01-01

    Full Text Available This paper describes a CFD study of the steam-reforming process (SRP of methanol in a short pseudo-contact time reactor of fixed bed type, in axi-symmetric conditions. The SRP is important sake for hydrogen production, and the design /scale-up/control of the industrial processes in the future are supported by a reliable knowledge and prediction of the catalytic reaction. The difficulty of determining the reaction scheme and the associated constants is wellknown, due to the necessity of identifying the reaction kinetics in purely chemical regime, meaning with a perfect homogeneity and flow independence. Practically these ideal conditions, albeit assumed, are not fulfilled so that the intrinsic chemical kinetics is not reached. For the case of SRP, we have attempted here to validate the Peppley’s model by a numerical modelling reproducing exactly the local conditions in the experimental duct, accounting for gradients in the cross section. The numerical results show the same trends than the experimental one, but with a slight shift of 20% as a consequence of the reactor heterogeneity. This result seems acceptable to validate the use of the Peepley’s model for further studies in other types of complex flow reactors.

  17. Hydrodynamics of multi-phase packed bed micro-reactors

    NARCIS (Netherlands)

    Márquez Luzardo, N.M.

    2010-01-01

    Why to use packed bed micro-reactors for catalyst testing? Miniaturized packed bed reactors have a large surface-to-volume ratio at the reactor and particle level that favors the heat- and mass-transfer processes at all scales (intra-particle, inter-phase and inter-particle or reactor level). If the

  18. Hydrodynamics of multi-phase packed bed micro-reactors

    NARCIS (Netherlands)

    Márquez Luzardo, N.M.

    2010-01-01

    Why to use packed bed micro-reactors for catalyst testing? Miniaturized packed bed reactors have a large surface-to-volume ratio at the reactor and particle level that favors the heat- and mass-transfer processes at all scales (intra-particle, inter-phase and inter-particle or reactor level). If the

  19. Engineering reactors for catalytic reactions

    Indian Academy of Sciences (India)

    Vivek V Ranade

    2014-03-01

    Catalytic reactions are ubiquitous in chemical and allied industries. A homogeneous or heterogeneous catalyst which provides an alternative route of reaction with lower activation energy and better control on selectivity can make substantial impact on process viability and economics. Extensive studies have been conducted to establish sound basis for design and engineering of reactors for practising such catalytic reactions and for realizing improvements in reactor performance. In this article, application of recent (and not so recent) developments in engineering reactors for catalytic reactions is discussed. Some examples where performance enhancement was realized by catalyst design, appropriate choice of reactor, better injection and dispersion strategies and recent advances in process intensification/ multifunctional reactors are discussed to illustrate the approach.

  20. In situ Fabrication of Monolithic Copper Azide

    Science.gov (United States)

    Li, Bing; Li, Mingyu; Zeng, Qingxuan; Wu, Xingyu

    2016-04-01

    Fabrication and characterization of monolithic copper azide were performed. The monolithic nanoporous copper (NPC) with interconnected pores and nanoparticles was prepared by decomposition and sintering of the ultrafine copper oxalate. The preferable monolithic NPC can be obtained through decomposition and sintering at 400°C for 30 min. Then, the available monolithic NPC was in situ reacted with the gaseous HN3 for 24 h and the monolithic NPC was transformed into monolithic copper azide. Additionally, the copper particles prepared by electrodeposition were also reacted with the gaseous HN3 under uniform conditions as a comparison. The fabricated monolithic copper azide was characterized by Fourier transform infrared (FTIR), inductively coupled plasma-optical emission spectrometry (ICP-OES), and differential scanning calorimetry (DSC).

  1. Novel bifunctional double-layer catalysts for application in microreactors for direct DME synthesis

    OpenAIRE

    Lee, Seungcheol

    2016-01-01

    This thesis describes experimental research toward the selective and efficient DME production from syngas in microstructured reactors using bifunctional catalysts. Two catalysts, Cu/ZnO/Al2O3 and ZSM-5, catalyze syngas conversion to methanol and methanol conversion to DME, respectively. The catalysts were prepared and successfully introduced in microchannel reactor for direct DME synthesis.

  2. High-density 3D graphene-based monolith and related materials, methods, and devices

    Energy Technology Data Exchange (ETDEWEB)

    Worsley, Marcus A.; Baumann, Theodore F.; Biener, Juergen; Charnvanichborikarn, Supakit; Kucheyev, Sergei; Montalvo, Elizabeth; Shin, Swanee; Tylski, Elijah

    2017-03-21

    A composition comprising at least one high-density graphene-based monolith, said monolith comprising a three-dimensional structure of graphene sheets crosslinked by covalent carbon bonds and having a density of at least 0.1 g/cm.sup.3. Also provided is a method comprising: preparing a reaction mixture comprising a suspension and at least one catalyst, said suspension selected from a graphene oxide (GO) suspension and a carbon nanotube suspension; curing the reaction mixture to produce a wet gel; drying the wet gel to produce a dry gel, said drying step is substantially free of supercritical drying and freeze drying; and pyrolyzing the dry gel to produce a high-density graphene-based monolith. Exceptional combinations of properties are achieved including high conductive and mechanical properties.

  3. High-density 3D graphene-based monolith and related materials, methods, and devices

    Science.gov (United States)

    Worsley, Marcus A.; Baumann, Theodore F.; Biener, Juergen; Charnvanichborikarn, Supakit; Kucheyev, Sergei; Montalvo, Elizabeth; Shin, Swanee; Tylski, Elijah

    2017-03-21

    A composition comprising at least one high-density graphene-based monolith, said monolith comprising a three-dimensional structure of graphene sheets crosslinked by covalent carbon bonds and having a density of at least 0.1 g/cm.sup.3. Also provided is a method comprising: preparing a reaction mixture comprising a suspension and at least one catalyst, said suspension selected from a graphene oxide (GO) suspension and a carbon nanotube suspension; curing the reaction mixture to produce a wet gel; drying the wet gel to produce a dry gel, said drying step is substantially free of supercritical drying and freeze drying; and pyrolyzing the dry gel to produce a high-density graphene-based monolith. Exceptional combinations of properties are achieved including high conductive and mechanical properties.

  4. Growing a carbon nano-fiber layer on a monolith support; effect of nickel loading and growth conditions

    NARCIS (Netherlands)

    Jarrah, Nabeel A.; Ommen, van Jan G.; Lefferts, Leon

    2004-01-01

    This work describes how a new, extremely porous, hairy layer of carbon nano-fibers (CNFs) can be prepared on the surface of porous inorganic bodies, e.g. wash-coated monoliths. CNFs were prepared catalytically by methane and ethene decomposition over a Ni catalyst. The influence of the Ni particle s

  5. Determination of the N{sub 2}O composition parameters on a three way catalyst in a synthesis gas reactor; Ermittlung der N{sub 2}O-Bildungsparameter am geregelten Dreiwegekatalysator von Kraftfahrzeugen in einem Hochtemperatur-Stroemungsreaktor

    Energy Technology Data Exchange (ETDEWEB)

    Meyer-Pittroff, R.; Gifhorn, A.; Rabl, H.P.

    1998-10-01

    The determination of the N{sub 2}O composition parameters on three-way catalysts (TWC) took place on an engine bench and in a high temperature flow reactor. The influences of exhaust gas components, temperature, air fuel ratio, gas hour space velocity, precious metal loading, catalyst aging and oxygen storage capacity were checked with transient and intransient experiments. 16 different catalyst samples were tested. The experiments show that the N{sub 2}O formation is a function of the catalyst temperature and the air fuel ratio. Under rich conditions N{sub 2}O formed in a temperature range that is limited by the beginning of the NO conversion at lower temperatures and by the oxidation of all reducing components at higher temperatures; under rich conditions range is limited by the beginning of the NO conversion and the dissociation of N{sub 2}O at TWC. It is a result of catalyst aging that at aged TWC samples the NO conversion and the N{sub 2}O formation is shifted up to higher temperatures. Another important influence is the TWC coating. The investigations show that the absolute as well as the selective N{sub 2}O formation at TWC samples coated with Pt/Pd/Rh- and Pd/Rh is higher than the N{sub 2}O formation at TWC samples coated with Pt/Rh. Simultaneously it could be observed that Pt/Pd/Rh samples show a higher oxygen storage capacity than Pt/Rh. (orig.) [Deutsch] Die Ermittlung der N{sub 2}O-Bildungsparameter an Dreiwegekatalysatoren erfolgte an einem Motorpruefstand und an einem Modellabgasreaktor. In stationaeren und instationaeren Versuchen wurden die Einfluesse von einzelnen Ottomotorabgaskomponenten, Temperatur, Luftverhaeltnis, Raumgeschwindigkeit, Edelmetallbeschichtung, Katalysatoralterung, Sauerstoffspeicherfaehigkeit untersucht. Fuer die Untersuchung standen 16 verschiedene Beschichtungen zur Verfuegung. Die N{sub 2}O-Bildung wird entscheidend vom Luftverhaeltnis und der Katalysatortemperatur bestimmt. Bei unterstoechiometrischen Abgaszusammensetzungen

  6. Detailed surface reaction mechanism in a three-way catalyst.

    Science.gov (United States)

    Chatterjee, D; Deutschmann, O; Warnatz, J

    2001-01-01

    Monolithic three-way catalysts are applied to reduce the emission of combustion engines. The design of such a catalytic converter is a complex process involving the optimization of different physical and chemical parameters (in the simplest case, e.g., length, cell densities or metal coverage of the catalyst). Numerical simulation can be used as an effective tool for the investigation of the catalytic properties of a catalytic converter and for the prediction of the performance of the catalyst. To attain this goal, a two-dimensional flow-field description is coupled with a detailed surface reaction model (gas-phase reactions can be neglected in three-way catalysts). This surface reaction mechanism (with C3H6 taken as representative of unburnt hydrocarbons) was developed using sub-mechanisms recently developed for hydrogen, carbon monoxide and methane oxidation, literature values for C3H6 oxidation, and estimates for the remaining unknown reactions. Results of the simulation of a monolithic single channel are used to validate the surface reaction mechanism. The performance of the catalyst was simulated under lean, nearly stoichiometric and rich conditions. For these characteristic conditions, the oxidation of propene and carbon monoxide and the reduction of NO on a typical Pt/Rh coated three-way catalyst were simulated as a function of temperature. The numerically predicted conversion data are compared with experimentally measured data. The simulation further reveals the coupling between chemical reactions and transport processes within the monolithic channel.

  7. Catalyst and method for reduction of nitrogen oxides

    Science.gov (United States)

    Ott, Kevin C.

    2008-05-27

    A Selective Catalytic Reduction (SCR) catalyst was prepared by slurry coating ZSM-5 zeolite onto a cordierite monolith, then subliming an iron salt onto the zeolite, calcining the monolith, and then dipping the monolith either into an aqueous solution of manganese nitrate and cerium nitrate and then calcining, or by similar treatment with separate solutions of manganese nitrate and cerium nitrate. The supported catalyst containing iron, manganese, and cerium showed 80 percent conversion at 113 degrees Celsius of a feed gas containing nitrogen oxides having 4 parts NO to one part NO.sub.2, about one equivalent ammonia, and excess oxygen; conversion improved to 94 percent at 147 degrees Celsius. N.sub.2O was not detected (detection limit: 0.6 percent N.sub.2O).

  8. Continuous-Flow Monolithic Silica Microreactors with Arenesulphonic Acid Groups: Structure–Catalytic Activity Relationships

    Directory of Open Access Journals (Sweden)

    Agnieszka Ciemięga

    2017-08-01

    Full Text Available The performance of monolithic silica microreactors activated with sulphonic acid groups and a packed bed reactor with Amberlyst 15 resin were compared in the esterification of acetic acid with n-butanol. The monolithic microreactors were made of single silica rods with complex pore architecture, differing in the size of mesopores, and in particular, flow-through macropores which significantly affected the flow characteristic of the continuous system. The highest ester productivity of 105.2 mol·molH+−1·h−1 was achieved in microreactor M1 with the largest porosity, characterized by a total pore volume of 4 cm3·g−1, mesopores with 20 nm diameter, and large flow-through macropores 30–50 μm in size. The strong impact of the permeability of the monoliths on a reaction kinetics was shown.

  9. Development and Commercial Application of DZC Ⅱ-1 Type Catalyst for Hydrogenation of Pyrolysis Gasoline

    Institute of Scientific and Technical Information of China (English)

    Zhao Ye; Wang Fucun

    2006-01-01

    Commercial application of the DZC Ⅱ-1 catalyst developed on the basis of the DZ-1 catalyst was introduced. The application tests of the catalyst under overload had proved that this catalyst demon-strated satisfactory adaptability to feedstock after continued operation for 20 months with little changes in the bed pressure drop, the reactor inlet temperature and the bed temperature rise. The DZC Ⅱ-1 catalyst was regarded as the best catalyst for the second-stage hydrogenation of pyrolysis gasoline.

  10. Scale up and stability test for oxidative coupling of methane over Na2WO4-Mn/SiO2 catalyst in a 200 ml fixed-bed reactor

    Institute of Scientific and Technical Information of China (English)

    Haitao Liu; Xiaolai Wang; Dexin Yang; Runxiong Gao; Zhonglai Wang; Jian Yang

    2008-01-01

    The study of scale up for the oxidative coupling of methane (OCM) has been carried out in a 200 ml stainless steel fixed-bed reactor over a 5wt% Na2WO4-1.9wt% Mn/SiO2 (W-Mn/SiO2) catalyst. The effects of reaction conditions were investigated in detail. The results showed that, with increasing reaction temperature, the gas-phase reaction was enhanced and a significant amount of methane was converted into COX; with the CH4/O2 molar ratio of 5, the highest C2 (ethylene and ethane) yield of 25% was achieved; the presence of steam (as diluent) had a positive effect on the C2 selectivity and yield. Under lower methane gaseous hourly space velocity (GHSV), higher selectivity and yield of C2 were obtained as the result of the decrease of released heat energy. In 100 h reaction time, the C2 selectivity of 66%-61 % and C2 yield of 24.2%-25.4% were achieved by a single pass without any significant loss in catalytic performance.

  11. CFD simulation of fixed-bed methanation reactor with double catalyst layers%双催化层固定床甲烷化反应器 CFD 模拟

    Institute of Scientific and Technical Information of China (English)

    赵静; 张亚新; 冉文燊; 程源洪

    2015-01-01

    温度分布直接影响着固定床甲烷化反应器的甲烷产量和设备安全性.以年产 12.75 亿立方煤制天然气绝热甲烷化反应器为研究对象,在建立真实设备三维模型的基础上,利用 ANSYS-CFX 有限元数值模拟的方法,建立多孔介质内化学反应、热交换与质量传递的气-固两相反应器模型,获得了双段固定床甲烷化反应器内部温度、压力、速度场的分布规律及甲烷产率分布.对不同床层结构对应的特征场分布进行了探索,分析了床层结构对各特征场分布的影响,确定了床层结构优化方案,MCR 催化剂床层出口处支撑延长的结构更有利于温度场沿反应器径向的均匀分布和甲烷质量分数的提高.对反应器入口温度、空速、压力对特征参数分布的影响进行了研究,提出了针对本工艺的允许入口参数波动范围.%The temperature distribution has its influence directly on methane production and equipment safety of the fixed-bed methanation reactor. To research the adiabatic methanation reactor which can produce 1.275 billion cubic meters SNG a year, the three-dimensional entity model was set up. A gas-solid two-phase reactor model for chemical reactions, heat exchange and mass transfer in porous media was established by the software ANSYS-CFX. The internal profile of temperature, pressure and velocity field and the methane yield profile in the fixed-bed internal methanation reactor with double catalyst layers were obtained. Based on the finite element numerical simulation method, the characteristic field distributions of different bed structures were explored. The influence of the bed structure on each characteristic field profile was analyzed, and then, the structure optimization of the bed layer was determined. The structure of the end support extend model was more favorable of the temperature profile along the radial of the reactor and the improvement of the methane mass fraction. The entrance

  12. Method of performing sugar dehydration and catalyst treatment

    Science.gov (United States)

    Hu, Jianli [Kennewick, WA; Holladay, Johnathan E [Kennewick, WA; Zhang, Xinjie [Burlington, MA; Wang, Yong [Richland, WA

    2010-06-01

    The invention includes a method of treating a solid acid catalyst. After exposing the catalyst to a mixture containing a sugar alcohol, the catalyst is washed with an organic solvent and is then exposed to a second reaction mixture. The invention includes a process for production of anhydrosugar alcohol. A solid acid catalyst is provided to convert sugar alcohol in a first sample to an anhydrosugar alcohol. The catalyst is then washed with an organic solvent and is subsequently utilized to expose a second sample. The invention includes a method for selective production of an anhydrosugar. A solid acid catalyst is provided within a reactor and anhydrosugar alcohol is formed by flowing a starting sugar alcohol into the reactor. The acid catalyst is then exposed to an organic solvent which allows a greater amount of additional anhydrosugar to be produced than would occur without exposing the acid catalyst to the organic solvent.

  13. Pressure drop in CIM disk monolithic columns.

    Science.gov (United States)

    Mihelic, Igor; Nemec, Damjan; Podgornik, Ales; Koloini, Tine

    2005-02-11

    Pressure drop analysis in commercial CIM disk monolithic columns is presented. Experimental measurements of pressure drop are compared to hydrodynamic models usually employed for prediction of pressure drop in packed beds, e.g. free surface model and capillary model applying hydraulic radius concept. However, the comparison between pressure drop in monolith and adequate packed bed give unexpected results. Pressure drop in a CIM disk monolithic column is approximately 50% lower than in an adequate packed bed of spheres having the same hydraulic radius as CIM disk monolith; meaning they both have the same porosity and the same specific surface area. This phenomenon seems to be a consequence of the monolithic porous structure which is quite different in terms of the pore size distribution and parallel pore nonuniformity compared to the one in conventional packed beds. The number of self-similar levels for the CIM monoliths was estimated to be between 1.03 and 2.75.

  14. Graphene-supported metal oxide monolith

    Energy Technology Data Exchange (ETDEWEB)

    Worsley, Marcus A.; Baumann, Theodore F.; Biener, Juergen; Biener, Monika A.; Wang, Yinmin; Ye, Jianchao; Tylski, Elijah

    2017-01-10

    A composition comprising at least one graphene-supported metal oxide monolith, said monolith comprising a three-dimensional structure of graphene sheets crosslinked by covalent carbon bonds, wherein the graphene sheets are coated by at least one metal oxide such as iron oxide or titanium oxide. Also provided is an electrode comprising the aforementioned graphene-supported metal oxide monolith, wherein the electrode can be substantially free of any carbon-black and substantially free of any binder.

  15. Graphene-supported metal oxide monolith

    Science.gov (United States)

    Worsley, Marcus A.; Baumann, Theodore F.; Biener, Juergen; Biener, Monika A.; Wang, Yinmin; Ye, Jianchao; Tylski, Elijah

    2017-01-10

    A composition comprising at least one graphene-supported metal oxide monolith, said monolith comprising a three-dimensional structure of graphene sheets crosslinked by covalent carbon bonds, wherein the graphene sheets are coated by at least one metal oxide such as iron oxide or titanium oxide. Also provided is an electrode comprising the aforementioned graphene-supported metal oxide monolith, wherein the electrode can be substantially free of any carbon-black and substantially free of any binder.

  16. Microstructured reactors for hydrogen production

    Energy Technology Data Exchange (ETDEWEB)

    Aartun, Ingrid

    2005-07-01

    -products upon steam addition leads to a decrease in CO selectivity without any significant change in the hydrogen selectivity. The Rh/foams of the lowest loadings (0.025 wt.%) yield the highest maximum catalyst temperatures and also display higher propane conversion than the 0.077 wt.% and 0.169 wt.% Rh/Al2O3 for both POX and OSR. However, the oxygen conversion does not reach completion and the hydrogen selectivity is lower, compared to the higher loadings. These effects of loading could be ascribed to differences in particle composition and structure. TPR suggested that a part of the Rh is present as a less reducible phase on the 0.025 wt.% Rh/Al2O3 foams as compared to the higher loadings. The Rh/Al2O3/Fecralloy microchannel reactor and the 0.025 wt.% Rh/Al2O3 foams were subjected to experiments with changing residence time. Changing the residence time interval corresponding to 1000 - 2000 Nml/min reactant flow has little influence on conversion and selectivity over the foams but lowering the residence time below 10 ms (flows higher than 1000 Nml/min) for the Rh/Al2O3/Fecralloy reactor increases the synthesis gas (H2 and CO) selectivity during both POX and OSR. This probably due to quenching of the gas phase reactions at high linear gas velocity and suggests that direct formation of hydrogen and CO is part of the reaction scheme. Microchannel reactors thus have potential for isolating kinetic effects and minimising gas phase contributions. The Rh/Al2O3 foams show significant deactivation upon a few temperature cycles under reactant exposure, strongest with steam present in the reactant mixture. FE-SEM analyses confirm that Rh sinter into larger particles upon exposure to reaction conditions, more pronounced when steam is fed. No deactivation is observed for the Rh/Al2O3/Fecralloy microchannel monoliths despite repeated temperature cycling under POX and OSR reactant exposure. In fact the selectivity to synthesis gas increases upon time. (Author)

  17. Catalyst deactivation. Is it predictable? What to do?

    Energy Technology Data Exchange (ETDEWEB)

    Moulijn, J.A.; Van Diepen, A.E.; Kapteijn, F. [Department of Chemical Process Technology, Section of Industrial Catalysis, Faculty of Applied Sciences, Delft University of Technology, Julianalaan 136, 2628 BL Delft (Netherlands)

    2001-04-30

    Catalyst deactivation is usually inevitable, although the rate at which it occurs varies greatly. This article discusses the causes of deactivation and the influence on reaction rate. Methods for minimising catalyst deactivation, by tailoring catalyst properties and/or process operations, are presented, as well as reactor configurations suitable for the regeneration of deactivated catalysts. Alkane dehydrogenation is used as an example to demonstrate the variety of engineering solutions possible.

  18. Evaluation of an EMITEC resistively heated metal monolith catalytic converter on two M100 neat methanol-fueled vehicles

    Science.gov (United States)

    Piotrowski, Gregory K.; Schaefer, Ronald M.

    1992-12-01

    The report describes the evaluation of a resistively heated catalyst system on two different methanol fueled vehicles. The EMITEC catalyst consisted of a compact resistively heated metal monolith in front of a larger conventional main converter. The EMITEC catalyst was evaluated on two neat methanol-fueled vehicles, a 1981 Volkswagen Rabbit and a 1988 Toyota Corolla. Emission testing was conducted over the Federal Test Procedure (FTP) CVS-75 test cycle. The emissions of primary interest were cold start methanol (unburned fuel), carbon monoxide, and formaldehyde.

  19. Synthesis of Mesoporous Titania-Silica Monolith Composites — A Comprehensive Study on their Photocatalytic Degradation of Acid Blue 113 Dye Under UV Light

    Science.gov (United States)

    Thejaswini, Thurlapathi Vl; Prabhakaran, Deivasigamani

    2016-10-01

    The present work deals with the synthesis of bi-continuous macro and mesoporous crack-free titania-silica monoliths, with well-defined structural dimensions and high surface area. The work also highlights their potential photocatalytic environmental applications. The highly ordered titania-silica monoliths are synthesized through direct surface template method using organic precursors of silica and titania in the presence of surface directing agents such as pluronic P123 and PEG, under acetic acid medium. The monoliths are synthesized with different Ti/Si ratios to obtain monolithic designs that exhibit better photocatalytic activity for dye degradation. The titania-silica monoliths are characterized using XRD, SEM, EDAX, FT-IR, TG-DTA and BET analysis. The photocatalytic activity of the synthesized monoliths is tested on the photodegradation of a textile dye (acid blue 113). It is observed that the monolith with 7:3 ratio of Ti/Si showed significant photocatalysis behavior in the presence of UV light. The influence of various physico-chemical properties such as, solution pH, photocatalyst dosage, light intensity, dye concentration, effect of oxidants, etc. are analyzed and optimized using a customized photoreactor set-up. Under optimized conditions, the monoliths exhibited superior degradation kinetics, with the dye dissipation complete within 10min of photolysis. The mesoporous catalysts are recoverable and reusable up to four cycles of repeated usage.

  20. Homogeneous catalysts

    CERN Document Server

    Chadwick, John C; Freixa, Zoraida; van Leeuwen, Piet W N M

    2011-01-01

    This first book to illuminate this important aspect of chemical synthesis improves the lifetime of catalysts, thus reducing material and saving energy, costs and waste.The international panel of expert authors describes the studies that have been conducted concerning the way homogeneous catalysts decompose, and the differences between homogeneous and heterogeneous catalysts. The result is a ready reference for organic, catalytic, polymer and complex chemists, as well as those working in industry and with/on organometallics.

  1. Biodiesel Production in a Fixed-Bed Reactor Using D296R as Heterogeneous Base Catalyst%D296R固定床催化酯化制备生物柴油

    Institute of Scientific and Technical Information of China (English)

    陈冠益; 王祎; 赵鹏程; 颜蓓蓓; 陈鸿

    2015-01-01

    The macroporous base anion-exchange resin D296R was pretreated, transformed and regenerated to be used as the heterogeneous catalyst in a fixed-bed reactor for biodiesel production. By comparing to other resin catalysts, the effects of different reaction temperatures, molar ratios of methanol to oil and reaction residence times on biodiesel yield were studied. D296R showed strong catalytic activity and stability in yield of fatty acid methyl esters (FAME) by transesterification reaction. With molar ratio of methanol to oil being 9∶1, the biodiesel yield of D296R catalyzed transesterification is 89.5%at a reaction temperature of 55℃and a reaction time of 60 min. Guidelines for continuous production of biodiesel as well as its large-scale industrial application are provided based on the insight gained from the experimental results.%对D296R大孔型强碱性阴离子交换树脂进行预处理、转型、再生,并用于固定床反应装置内催化棕榈油和甲醇进行连续酯交换反应,通过与其他树脂催化剂对比,研究了不同反应温度、醇油摩尔比和反应停留时间对生物柴油收率的影响.采用该催化剂催化制备生物柴油,催化活性较高.在醇油摩尔比为9∶1、反应温度为55,℃、反应停留时间为60,min 时,酯交换制备生物柴油的产率达到89.5%.本研究对用于生物柴油的连续制备和大规模工业化生产有着重要的意义.

  2. Combination of plasma with a honeycomb-structured catalyst for automobile exhaust treatment.

    Science.gov (United States)

    Kang, Woo Seok; Lee, Dae Hoon; Lee, Jae-Ok; Hur, Min; Song, Young-Hoon

    2013-10-01

    To activate a catalyst efficiently at low temperature by plasma for environmental control, we developed a hybrid reactor that combines plasma with a honeycomb-structured catalyst in a practical manner. The reactor developed generated stable cold plasma at atmospheric pressure because of the dielectric and conductive nature of the honeycomb catalyst by consuming low amounts of power. In this reactor, the applied voltage and temperature determined the balance between the oxidation and adsorption by the plasma and catalyst. The synergistic reaction of the plasma and catalyst was more effective at low temperatures, resulting in a reduction in a lowered light-off temperature.

  3. Desempenho de um reator integral de reforma a vapor de metano recheado com um catalisador industrial = Performance of an integral methane reforming fixed bed reactor packed with an industrial catalyst

    Directory of Open Access Journals (Sweden)

    Douglas Rodrigues Francisquini

    2005-07-01

    Full Text Available O presente trabalho tem por objetivo avaliar a atividade catalítica e o perfil de temperaturas num reator integral de reforma a vapor de metano, aquecido por forno elétrico e recheado com um catalisador industrial. Foram efetuadas medidas de temperatura no leito em nove posições axiais distintas e a composição dos produtos da reação foram determinadas por cromatografia. Os ensaios foram conduzidos com o forno a 500, 600 e 700ºC, razão molar de alimentação [H2O/CH4 ] = 4 e densidade fluxo-mássico de 0,2 e 0,5 kg/m2.s. Os resultados indicam que a utilização dos nove pontos foi suficiente para representar o comportamento térmico do reator e evidenciam a existência de perdas decalor significativas nas extremidades do reator. Tanto a atividade catalítica como a conversão apresentam-se sensíveis à temperatura operacional, entretanto, a temperatura do leito é praticamente insensível à vazão nas condições experimentais exploradas.The present work has the objective to evaluate the catalytic activity and the temperature profile inside an integral steam reforming fixed bed reactor heated by an electrical furnace and packed with an industrial catalyst. Nine temperature measures were made along nine axial positions and the composition of the products reaction were evaluated by gas chromatography. The experimental conditions were: temperatures furnace of 500ºC, 600ºC, and 700ºC, feed molar ratio [H2O/CH4] = 4, and mass flow rate of 0.2 and 0.5 kg/m2.s. The results show that the use of the nine points was enough to represent the thermal behavior of the reactor. Both the catalytic activity and the conversion depend of operational temperature. However, the fixed bedtemperature is independent of mass flow rate at the used experimental conditions.

  4. Monolithically integrated absolute frequency comb laser system

    Energy Technology Data Exchange (ETDEWEB)

    Wanke, Michael C.

    2016-07-12

    Rather than down-convert optical frequencies, a QCL laser system directly generates a THz frequency comb in a compact monolithically integrated chip that can be locked to an absolute frequency without the need of a frequency-comb synthesizer. The monolithic, absolute frequency comb can provide a THz frequency reference and tool for high-resolution broad band spectroscopy.

  5. Nanosecond monolithic CMOS readout cell

    Science.gov (United States)

    Souchkov, Vitali V.

    2004-08-24

    A pulse shaper is implemented in monolithic CMOS with a delay unit formed of a unity gain buffer. The shaper is formed of a difference amplifier having one input connected directly to an input signal and a second input connected to a delayed input signal through the buffer. An elementary cell is based on the pulse shaper and a timing circuit which gates the output of an integrator connected to the pulse shaper output. A detector readout system is formed of a plurality of elementary cells, each connected to a pixel of a pixel array, or to a microstrip of a plurality of microstrips, or to a detector segment.

  6. Compact monolithic capacitive discharge unit

    Science.gov (United States)

    Roesler, Alexander W.; Vernon, George E.; Hoke, Darren A.; De Marquis, Virginia K.; Harris, Steven M.

    2007-06-26

    A compact monolithic capacitive discharge unit (CDU) is disclosed in which a thyristor switch and a flyback charging circuit are both sandwiched about a ceramic energy storage capacitor. The result is a compact rugged assembly which provides a low-inductance current discharge path. The flyback charging circuit preferably includes a low-temperature co-fired ceramic transformer. The CDU can further include one or more ceramic substrates for enclosing the thyristor switch and for holding various passive components used in the flyback charging circuit. A load such as a detonator can also be attached directly to the CDU.

  7. H Reactor

    Data.gov (United States)

    Federal Laboratory Consortium — The H Reactor was the first reactor to be built at Hanford after World War II.It became operational in October of 1949, and represented the fourth nuclear reactor on...

  8. Catalysts for decomposing ozone tail gas

    Institute of Scientific and Technical Information of China (English)

    LIU Chang-an; SUN De-zhi; WANG Hui; LI Wei

    2003-01-01

    The preparation of immobilizing-catalysts for decomposing ozone by using dipping method was studied. XRD, XPS and TEM were used to characterize the catalysts. The three kinds of catalysts were selected preferentially, and their catalytic activities were investigated. The results showed that the catalyst with activated carbon dipping acetate (active components are Mn: Cu = 3:2, active component proportion in catalyst is 15%, calcination temperature is 200℃ ) has the best catalytic activity for ozone decomposing. One gram of catalyst can decompose 17.6 g ozone at initial ozone concentration of 2.5 g/m3 and the residence time in reactor of 0.1 s. The experimental results also indicated that humidity of reaction system had negative effect on catalytic activity.

  9. Synthesis and characterization of mesoporous hydrocracking catalysts

    Science.gov (United States)

    Munir, D.; Usman, M. R.

    2016-08-01

    Mesoporous catalysts have shown great prospective for catalytic reactions due to their high surface area that aids better distribution of impregnated metal. They have been found to contain more adsorption sites and controlled pore diameter. Hydrocracking, in the presence of mesoporous catalyst is considered more efficient and higher conversion of larger molecules is observed as compared to the cracking reactions in smaller microporous cavities of traditional zeolites. In the present study, a number of silica-alumina based mesoporous catalysts are synthesized in the laboratory. The concentration and type of surfactants and quantities of silica and alumina sources are the variables studied in the preparation of catalyst supports. The supports prepared are well characterized using SEM, EDX, and N2-BET techniques. Finally, the catalysts are tested in a high pressure autoclave reactor to study the activity and selectivity of the catalysts for the hydrocracking of a model mixture of plastics comprising of LDPE, HDPE, PP, and PS.

  10. Fast preparation of photopolymerized monolithic columns for capillary electrochromatography

    Institute of Scientific and Technical Information of China (English)

    GONG Wen-jun; XU Guang-ri; ZHANG Yi-jun; ZHANG Yu-ping; CHOI Seong-ho; LEE Kwang-pill

    2008-01-01

    Photopolymerized sol-gel(PSG) columns were prepared using methacryloxypropyltrimethoxysilane as the monomer,toluene as the porogen and hydrochloric acid as the catalyst. Four different photoinitiators such as benzoin methyl ether, Irgacure 819,lrgacure 1700 and Irgacure 1800 were comparatively used in the reaction solution in the presence and absence of sodium dodecylsulfate. The above eight solutions were respectively irradiated at 365 um for 5-10 min in each capillary (75 μm inside diameter) toprepare the porous monolithic sol-gel column by a one-step, in situ, process. The chromatographic behavior of the eight PSGcolumns were comparatively studied, all of which exhibit reversed-phase character. Using these columns, several neutral compounds,namely thiourea, benzene, toluene, ethyl benzene, biphenyl and naphthalene can be separated from mixtures with a largest columnefficiency of 74 470 plate/column for thiourea. Addition of sodium dodecyl sulfate in the polymerization process has a significantinfluence on the morphology and migration time.

  11. Facile construction of macroporous hybrid monoliths via thiol-methacrylate Michael addition click reaction for capillary liquid chromatography.

    Science.gov (United States)

    Lin, Hui; Ou, Junjie; Liu, Zhongshan; Wang, Hongwei; Dong, Jing; Zou, Hanfa

    2015-01-30

    A facile approach based on thiol-methacrylate Michael addition click reaction was developed for construction of porous hybrid monolithic materials. Three hybrid monoliths were prepared via thiol-methacrylate click polymerization by using methacrylate-polyhedral oligomeric silsesquioxane (POSS) (cage mixture, n=8, 10, 12, POSS-MA) and three multi-thiol crosslinkers, 1,6-hexanedithiol (HDT), trimethylolpropane tris(3-mercaptopropionate) (TPTM) and pentaerythritol tetrakis(3-mercaptopropionate) (PTM), respectively, in the presence of porogenic solvents (n-propanol and PEG 200) and a catalyst (dimethylphenylphosphine, DMPP). The obtained monoliths possessed high thermal and chemical stabilities. Besides, they all exhibited high column efficiencies and excellent separation abilities in capillary liquid chromatography (cLC). The highest column efficiency could reach ca. 195,000N/m for butylbenzene on the monolith prepared with POSS-MA and TPTM (monolith POSS-TPTM) in reversed-phase (RP) mode at 0.64mm/s. Good chromatographic performance were all achieved in the separations of polycyclic aromatic hydrocarbons (PAHs), phenols, anilines, EPA 610 as well as bovine serum albumin (BSA) digest. The high column efficiencies in the range of 51,400-117,000N/m (achieved on the monolith POSS-PTM in RP mode) convincingly demonstrated the high separation abilities of these thiol-methacrylate based hybrid monoliths. All the results demonstrated the feasibility of the phosphines catalyzed thiol-methacrylate Michael addition click reaction in fabrication of monolithic columns with high efficiency for cLC applications. Copyright © 2014 Elsevier B.V. All rights reserved.

  12. Modeling Deactivation of Catalysts for Selective Catalytic Reduction of NOx by KCl Aerosols

    DEFF Research Database (Denmark)

    Olsen, Brian Kjærgaard; Castellino, Francesco; Jensen, Anker Degn

    2017-01-01

    with the catalyst at the surface of the monolith wall, the transport and accumulation of potassium, bound to Brønsted acid sites, throughout the catalyst wall, and the resulting loss in SCR activity. Using an experimentally measured KCl aerosol size distribution as input, the model can replicate the observed...... if the particle size of the incoming aerosol is increased. The model provides, for the first time, a mechanistic framework for understanding and modeling SCR catalyst deactivation by KCl that may be applicable also for deactivation by other salts and at different operating conditions.......A detailed model for the deactivation of a V2O5–WO3/TiO2-based SCR monolith catalyst by potassium poisoning has been developed and validated. The model accounts for deposition of KCl aerosol particles present in the flue gas on the external catalyst surface, the reaction of the deposited particles...

  13. Application of LY-C2-12 D catalyst in C2 hydrogenation isothermal reactor of 330 kt·a-1 ethylene plant%LY-C2-12 D催化剂在330 kt · a-1乙烯装置碳二加氢等温反应器的工业应用

    Institute of Scientific and Technical Information of China (English)

    赵玉龙

    2015-01-01

    中国石油大庆石化公司330 kt·a-1乙烯装置是我国较早成套引进的乙烯装置。该装置碳二加氢一段反应器采用等温反应器,列管之间使用丁烷为冷却介质。第一段反应器采用新型LY-C2-12 D催化剂,运转初期乙烯选择性为80%,运行6个多月,平均选择性达70%,表明该催化剂具有良好的稳定性。%330 kt·a-1 ethylene plant in PetroChina Daqing Petrochemical Co. is one of the earliest im-ported ethylene plants in China. The isothermal reactor is applied as C2 hydrogenation reactor and butane is used for cooling medium among the tubes. The new LY-C2-12D catalyst was applied in the first stage reactor. The selectivity to ethylene reached 80% in initial running period,and the average selectivity was up to 70%,which indicated that the catalyst possessed good stability.

  14. Evolution patterns and family relations in G-S reactors

    NARCIS (Netherlands)

    van Swaaij, Willibrordus Petrus Maria; van der Ham, Aloysius G.J.; Kronberg, Alexandre E.

    2002-01-01

    Reactor selection strategies for gas–solid (G–S) heterogeneously catalysed processes can be based on the requirements of the desired process and the properties of the reactions and catalysts involved. Ultimately a reactor selection will nearly always be grounded on existing or emerging reactor types

  15. Microfluidic devices and methods including porous polymer monoliths

    Science.gov (United States)

    Hatch, Anson V; Sommer, Gregory J; Singh, Anup K; Wang, Ying-Chih; Abhyankar, Vinay V

    2014-04-22

    Microfluidic devices and methods including porous polymer monoliths are described. Polymerization techniques may be used to generate porous polymer monoliths having pores defined by a liquid component of a fluid mixture. The fluid mixture may contain iniferters and the resulting porous polymer monolith may include surfaces terminated with iniferter species. Capture molecules may then be grafted to the monolith pores.

  16. Unsteady processes in catalytic reactors

    Energy Technology Data Exchange (ETDEWEB)

    Matros, Yu.Sh.

    1985-01-01

    In recent years a realization has occurred that reaction and reactor dynamics must be considered when designing and operating catalytic reactors. In this book, the author has focussed on both the processes occurring on individual porous-catalyst particles as well as the phenomena displayed by collections of these particles in fixed-bed reactors. The major topics discussed include the effects of unsteady-state heat and mass transfer, the influence of inhomogeneities and stagnant regions in fixed beds, and reactor operation during forced cycling of operating conditions. Despite the title of the book, attention is also paid to the determination of the number and stability of fixed-bed steady states, with the aim of describing the possibility of controlling reactors at unstable steady states. However, this development is somewhat dated, given the recent literature on multiplicity phenomena and process control.

  17. Copper nanoparticles supported on permeable monolith with carboxylic acid surface functionality: Stability and catalytic properties under reductive conditions

    Energy Technology Data Exchange (ETDEWEB)

    Poupart, Romain; Le Droumaguet, Benjamin, E-mail: ledroumaguet@icmpe.cnrs.fr; Guerrouache, Mohamed; Carbonnier, Benjamin, E-mail: carbonnier@icmpe.cnrs.fr

    2015-08-01

    This work reported on the immobilization of copper metallic nanoparticles at the interface of mercaptosuccinic acid-functionalized N-acryloxysuccinimide-based monoliths. Upon photochemically-mediated free radical copolymerization of N-acryloxysuccinimide reactive monomer with ethylene glycol dimethacrylate cross-linker, reactive monoliths were obtained. Nucleophilic substitution of the N-hydroxysuccinimide moieties with allylamine, allowed for the synthesis of an olefin-functionalized monolith, as demonstrated by Raman spectroscopy. Mercaptosuccinic acid was anchored at the surface of the porous polymeric material through photochemically-driven thiol-ene “click” addition. In a final step, adsorption of copper nanoparticles at the surface of the resulting carboxylic acid functionalized monolith was achieved via two distinct pathways. It was either realized by percolation of a suspension of pre-formed copper nanoparticles through the capillary or by in situ reduction of Cu{sup (II)}Br{sub 2} salt solution preliminary flown through the monolith. After characterization of the resulting hybrids by scanning electron microscopy and energy-dispersive X-ray spectroscopy, investigations were further pursued regarding the catalytic behavior of such hybrid materials. The possibility to reduce 2-nitrophenol into the corresponding 2-aminophenol within a few minutes via a flow-through process inside the hybrid monolithic capillary was notably successfully demonstrated. - Graphical abstract: Display Omitted - Highlights: • Monolithic micro-reactors with surface immobilized copper nanoparticle for flow through catalytic processes. • Porous polymer-stabilized copper nanoparticles. • Photothiol-ene click chemistry for the effective surface functionalization of porous monolithic polymers. • Surface adsorption of copper nanoparticles through in-situ and ex-situ strategies.

  18. In situ Synthesis of Cu-SSZ-13/Cordierite Monolithic Catalyst for the Selective Catalytic Reduction of NO with NH3%Cu-SSZ-13/堇青石整体式催化剂的原位合成及其NH3选择性催化还原NO性能

    Institute of Scientific and Technical Information of China (English)

    张宇; 王红宁; 陈若愚

    2015-01-01

    采用水热合成技术,在堇青石蜂窝陶瓷载体上原位合成了SSZ-13分子筛,并借助X射线衍射(XRD)和场发射扫描电子显微镜(FESEM)等手段对其进行表征.在此基础上,研究了合成时间对催化剂结构和机械性能的影响.另外,使用固定床反应器测试了离子交换度为50%的Cu-SSZ-13/堇青石催化剂和Cu-SSZ-13催化剂水热老化前后的氨气选择性催化还原(NH3-SCR) NO性能.结果表明,通过原位合成法制备的Cu-SSZ-13/堇青石催化剂在200-500° C的窗口温度内能达到80%以上的转化率,并在300° C时达到96.4%的转化率.在850°C水热老化12 h后, Cu-SSZ-13催化剂完全丧失了催化性能,而Cu-SSZ-13/堇青石催化剂在300°C时仍然保持91%的转化率.使用XRD和固体27Al核磁共振(27Al NMR)的方法,研究了水热老化前后两种催化剂结构的变化,结果表明,当水热老化12 h后, Cu-SSZ-13基本丧失了SSZ-13结构特征峰,而Cu-SSZ-13/堇青石仍然保持了一定的SSZ-13骨架结构.证明了通过原位合成法制备的Cu-SSZ-13/堇青石催化剂具有较好的抗水热老化性能.%SSZ-13 molecular sieves were synthesized in situ on the surface of a honeycomb-shaped cordierite support using a hydrothermal method, and the resulting material was characterized by X-ray diffraction (XRD) and field emission scanning electron microscope (FESEM). The process for preparing SSZ-13/cordierite was optimized in detail. Furthermore, the ion exchange levels of the 50%Cu-SSZ-13/cordierite and Cu-SSZ-13 catalysts were tested in the ammonia-selective catalytic reduction (NH3-SCR) of NO both before and after the hydrothermal treatment process using a fixed-bed reactor. The results of these experiments showed that the Cu-SSZ-13/cordierite prepared in situ by hydrothermal synthesis had good catalytic activity, and gave an NO conversion of more than 80%at temperatures in the range of 200-500 °C, with the highest NO conversion of

  19. Catalyst mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Masel, Richard I.; Rosen, Brian A.

    2017-02-14

    Catalysts that include at least one catalytically active element and one helper catalyst can be used to increase the rate or lower the overpotential of chemical reactions. The helper catalyst can simultaneously act as a director molecule, suppressing undesired reactions and thus increasing selectivity toward the desired reaction. These catalysts can be useful for a variety of chemical reactions including, in particular, the electrochemical conversion of CO.sub.2 or formic acid. The catalysts can also suppress H.sub.2 evolution, permitting electrochemical cell operation at potentials below RHE. Chemical processes and devices using the catalysts are also disclosed, including processes to produce CO, OH.sup.-, HCO.sup.-, H.sub.2CO, (HCO.sub.2).sup.-, H.sub.2CO.sub.2, CH.sub.3OH, CH.sub.4, C.sub.2H.sub.4, CH.sub.3CH.sub.2OH, CH.sub.3COO.sup.-, CH.sub.3COOH, C.sub.2H.sub.6, O.sub.2, H.sub.2, (COOH).sub.2, or (COO.sup.-).sub.2, and a specific device, namely, a CO.sub.2 sensor.

  20. Photo-oxidation catalysts

    Science.gov (United States)

    Pitts, J. Roland; Liu, Ping; Smith, R. Davis

    2009-07-14

    Photo-oxidation catalysts and methods for cleaning a metal-based catalyst are disclosed. An exemplary catalyst system implementing a photo-oxidation catalyst may comprise a metal-based catalyst, and a photo-oxidation catalyst for cleaning the metal-based catalyst in the presence of light. The exposure to light enables the photo-oxidation catalyst to substantially oxidize absorbed contaminants and reduce accumulation of the contaminants on the metal-based catalyst. Applications are also disclosed.

  1. Anisotropically structured magnetic aerogel monoliths

    Science.gov (United States)

    Heiligtag, Florian J.; Airaghi Leccardi, Marta J. I.; Erdem, Derya; Süess, Martin J.; Niederberger, Markus

    2014-10-01

    Texturing of magnetic ceramics and composites by aligning and fixing of colloidal particles in a magnetic field is a powerful strategy to induce anisotropic chemical, physical and especially mechanical properties into bulk materials. If porosity could be introduced, anisotropically structured magnetic materials would be the perfect supports for magnetic separations in biotechnology or for magnetic field-assisted chemical reactions. Aerogels, combining high porosity with nanoscale structural features, offer an exceptionally large surface area, but they are difficult to magnetically texture. Here we present the preparation of anatase-magnetite aerogel monoliths via the assembly of preformed nanocrystallites. Different approaches are proposed to produce macroscopic bodies with gradient-like magnetic segmentation or with strongly anisotropic magnetic texture.Texturing of magnetic ceramics and composites by aligning and fixing of colloidal particles in a magnetic field is a powerful strategy to induce anisotropic chemical, physical and especially mechanical properties into bulk materials. If porosity could be introduced, anisotropically structured magnetic materials would be the perfect supports for magnetic separations in biotechnology or for magnetic field-assisted chemical reactions. Aerogels, combining high porosity with nanoscale structural features, offer an exceptionally large surface area, but they are difficult to magnetically texture. Here we present the preparation of anatase-magnetite aerogel monoliths via the assembly of preformed nanocrystallites. Different approaches are proposed to produce macroscopic bodies with gradient-like magnetic segmentation or with strongly anisotropic magnetic texture. Electronic supplementary information (ESI) available: Digital photographs of dispersions and gels with different water-to-ethanol ratios; magnetic measurements of an anatase aerogel containing 0.25 mol% Fe3O4 nanoparticles; XRD patterns of the iron oxide and

  2. Monolithic cells for solar fuels.

    Science.gov (United States)

    Rongé, Jan; Bosserez, Tom; Martel, David; Nervi, Carlo; Boarino, Luca; Taulelle, Francis; Decher, Gero; Bordiga, Silvia; Martens, Johan A

    2014-12-07

    Hybrid energy generation models based on a variety of alternative energy supply technologies are considered the best way to cope with the depletion of fossil energy resources and to limit global warming. One of the currently missing technologies is the mimic of natural photosynthesis to convert carbon dioxide and water into chemical fuel using sunlight. This idea has been around for decades, but artificial photosynthesis of organic molecules is still far away from providing real-world solutions. The scientific challenge is to perform in an efficient way the multi-electron transfer reactions of water oxidation and carbon dioxide reduction using holes and single electrons generated in an illuminated semiconductor. In this tutorial review the design of photoelectrochemical (PEC) cells that combine solar water oxidation and CO2 reduction is discussed. In such PEC cells simultaneous transport and efficient use of light, electrons, protons and molecules has to be managed. It is explained how efficiency can be gained by compartmentalisation of the water oxidation and CO2 reduction processes by proton exchange membranes, and monolithic concepts of artificial leaves and solar membranes are presented. Besides transferring protons from the anode to the cathode compartment the membrane serves as a molecular barrier material to prevent cross-over of oxygen and fuel molecules. Innovative nano-organized multimaterials will be needed to realise practical artificial photosynthesis devices. This review provides an overview of synthesis techniques which could be used to realise monolithic multifunctional membrane-electrode assemblies, such as Layer-by-Layer (LbL) deposition, Atomic Layer Deposition (ALD), and porous silicon (porSi) engineering. Advances in modelling approaches, electrochemical techniques and in situ spectroscopies to characterise overall PEC cell performance are discussed.

  3. Steam Reforming of Glycerol for Hydrogen Production over Catalyst

    OpenAIRE

    Sadanandam, G.; Sreelatha, N.; Phanikrishna Sharma, M. V.; Kishta Reddy, S.; B. Srinivas; K. Venkateswarlu; T. Krishnudu; Subrahmanyam, M; Durga Kumari, V.

    2012-01-01

    The performance of Ni/SiO2 catalyst for glycerol reforming has been investigated in fixed-bed reactor using careful tailoring of the operational conditions. In this paper, a commercial Engelhard catalyst has been sized and compared to gas product distribution versus catalyst size, water-to-carbon ratio, and stability of the catalyst system. Ni/SiO2 catalysts of three sizes (2×2, 2×4, and 3×5 mm) are evaluated using glycerol: water mixture at 600°C to produce 2 L H2 g−1 cat h−1. The results in...

  4. Monolithic Time Delay Integrated APD Arrays Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The overall goal of the proposed program by Epitaxial Technologies is to develop monolithic time delay integrated avalanche photodiode (APD) arrays with sensitivity...

  5. Reactor Physics

    Energy Technology Data Exchange (ETDEWEB)

    Ait Abderrahim, A

    2001-04-01

    The Reactor Physics and MYRRHA Department of SCK-CEN offers expertise in various areas of reactor physics, in particular in neutronics calculations, reactor dosimetry, reactor operation, reactor safety and control and non-destructive analysis of reactor fuel. This expertise is applied in the Department's own research projects in the VENUS critical facility, in the BR1 reactor and in the MYRRHA project (this project aims at designing a prototype Accelerator Driven System). Available expertise is also used in programmes external to the Department such as the reactor pressure steel vessel programme, the BR2 reactor dosimetry, and the preparation and interpretation of irradiation experiments by means of neutron and gamma calculations. The activities of the Fuzzy Logic and Intelligent Technologies in Nuclear Science programme cover several domains outside the department. Progress and achievements in these topical areas in 2000 are summarised.

  6. Monolithic multinozzle emitters for nanoelectrospray mass spectrometry

    Science.gov (United States)

    Wang, Daojing; Yang, Peidong; Kim, Woong; Fan, Rong

    2011-09-20

    Novel and significantly simplified procedures for fabrication of fully integrated nanoelectrospray emitters have been described. For nanofabricated monolithic multinozzle emitters (NM.sup.2 emitters), a bottom up approach using silicon nanowires on a silicon sliver is used. For microfabricated monolithic multinozzle emitters (M.sup.3 emitters), a top down approach using MEMS techniques on silicon wafers is used. The emitters have performance comparable to that of commercially-available silica capillary emitters for nanoelectrospray mass spectrometry.

  7. TECHNOLOGY DEVELOPMENT FOR IRON FISCHER-TROPSCH CATALYSTS

    Energy Technology Data Exchange (ETDEWEB)

    Davis, B.H.

    1998-07-22

    The goal of the proposed work described in this Final Report was the development of iron-based Fischer-Tropsch catalysts that combined high activity, selectivity and life with physical robustness for slurry phase reactors that will produce either low-alpha or high-alpha products. The work described here has optimized the catalyst composition and pretreatment operation for a low-alpha catalyst. In parallel, work has been conducted to design a high-alpha iron catalyst that is suitable for slurry phase synthesis. Studies have been conducted to define the chemical phases present at various stages of the pretreatment and synthesis stages and to define the course of these changes. The oxidation/reduction cycles that are anticipated to occur in large, commercial reactors have been studied at the laboratory scale. Catalyst performance has been determined for catalysts synthesized in this program for activity, selectivity and aging characteristics.

  8. Catalysts derived from waste slag for transesterification

    Institute of Scientific and Technical Information of China (English)

    Xiaowei Zhang; Wei Huang

    2011-01-01

    MgO-CaO/SiO2 solid catalysts derived from waste slag (WS) of metal magnesium plant were prepared.The catalytic performances were evaluated in the transesterification of rapeseed oil with methanol to biodiesel in a 500 mL three-necked reactor under atmospheric pressure.The basic strengh of the catalyst reached 22.0 measured by indicators accroding to Hammett scale.The results show that the MgO-CaO/SiO2 is an excellent catalyst for transesterification, and the conversion of rapeseed oil reach 98% under the optimum condition.

  9. Polyurea-Based Aerogel Monoliths and Composites

    Science.gov (United States)

    Lee, Je Kyun

    2012-01-01

    aerogel insulation material was developed that will provide superior thermal insulation and inherent radiation protection for government and commercial applications. The rubbery polyureabased aerogel exhibits little dustiness, good flexibility and toughness, and durability typical of the parent polyurea polymer, yet with the low density and superior insulation properties associated with aerogels. The thermal conductivity values of polyurea-based aerogels at lower temperature under vacuum pressures are very low and better than that of silica aerogels. Flexible, rubbery polyurea-based aerogels are able to overcome the weak and brittle nature of conventional inorganic and organic aerogels, including polyisocyanurate aerogels, which are generally prepared with the one similar component to polyurethane rubber aerogels. Additionally, with higher content of hydrogen in their structures, the polyurea rubber-based aerogels will also provide inherently better radiation protection than those of inorganic and carbon aerogels. The aerogel materials also demonstrate good hydrophobicity due to their hydrocarbon molecular structure. There are several strategies to overcoming the drawbacks associated with the weakness and brittleness of silica aerogels. Development of the flexible fiber-reinforced silica aerogel composite blanket has proven to be one promising approach, providing a conveniently fielded form factor that is relatively robust in industrial environments compared to silica aerogel monoliths. However, the flexible, silica aerogel composites still have a brittle, dusty character that may be undesirable, or even intolerable, in certain application environments. Although the cross - linked organic aerogels, such as resorcinol- formaldehyde (RF), polyisocyanurate, and cellulose aerogels, show very high impact strength, they are also very brittle with little elongation (i.e., less rubbery). Also, silica and carbon aerogels are less efficient radiation shielding materials due

  10. Activated Carbon Fiber Monoliths as Supercapacitor Electrodes

    Directory of Open Access Journals (Sweden)

    Gelines Moreno-Fernandez

    2017-01-01

    Full Text Available Activated carbon fibers (ACF are interesting candidates for electrodes in electrochemical energy storage devices; however, one major drawback for practical application is their low density. In the present work, monoliths were synthesized from two different ACFs, reaching 3 times higher densities than the original ACFs’ apparent densities. The porosity of the monoliths was only slightly decreased with respect to the pristine ACFs, the employed PVDC binder developing additional porosity upon carbonization. The ACF monoliths are essentially microporous and reach BET surface areas of up to 1838 m2 g−1. SEM analysis reveals that the ACFs are well embedded into the monolith structure and that their length was significantly reduced due to the monolith preparation process. The carbonized monoliths were studied as supercapacitor electrodes in two- and three-electrode cells having 2 M H2SO4 as electrolyte. Maximum capacitances of around 200 F g−1 were reached. The results confirm that the capacitance of the bisulfate anions essentially originates from the double layer, while hydronium cations contribute with a mixture of both, double layer capacitance and pseudocapacitance.

  11. Solvothermal removal of the organic template from L{sub 3} ('sponge') templated silica monoliths

    Energy Technology Data Exchange (ETDEWEB)

    Dabbs, Daniel M. [Princeton University, Department of Chemical Engineering (United States); Mulders, Norbert [University of Delaware, Department of Physics and Astronomy (United States); Aksay, Ilhan A. [Princeton University, Department of Chemical Engineering (United States)], E-mail: iaksay@princeton.EDU

    2006-10-15

    We compare the methods of continuous solvent (Soxhlet) and supercritical solvent extractions for the removal of the organic template from nanostructured silica monoliths. Our monoliths are formed by templating the L{sub 3} liquid crystal phase of cetylpyridinium chloride in aqueous solutions with tetramethoxy silane. The monoliths that result from both Soxhlet and supercritical extraction methods are mechanically robust, optically clear, and free of cracks. The Soxhlet method compares favorably with supercritical solvent extraction in that equivalent L{sub 3}-templated silica can be synthesized without the use of specialized reactor hardware or higher temperatures and high pressures, while avoiding noxious byproducts. The comparative effectiveness of various solvents in the Soxhlet process is related to the Hildebrand solubility parameter, determined by the effective surface area of the extracted silica.

  12. Reactor safeguards

    CERN Document Server

    Russell, Charles R

    1962-01-01

    Reactor Safeguards provides information for all who are interested in the subject of reactor safeguards. Much of the material is descriptive although some sections are written for the engineer or physicist directly concerned with hazards analysis or site selection problems. The book opens with an introductory chapter on radiation hazards, the construction of nuclear reactors, safety issues, and the operation of nuclear reactors. This is followed by separate chapters that discuss radioactive materials, reactor kinetics, control and safety systems, containment, safety features for water reactor

  13. Reactor operation

    CERN Document Server

    Shaw, J

    2013-01-01

    Reactor Operation covers the theoretical aspects and design information of nuclear reactors. This book is composed of nine chapters that also consider their control, calibration, and experimentation.The opening chapters present the general problems of reactor operation and the principles of reactor control and operation. The succeeding chapters deal with the instrumentation, start-up, pre-commissioning, and physical experiments of nuclear reactors. The remaining chapters are devoted to the control rod calibrations and temperature coefficient measurements in the reactor. These chapters also exp

  14. Highly dispersed metal catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, Xin; West, William L.; Rhodes, William D.

    2016-11-08

    A supported catalyst having an atomic level single atom structure is provided such that substantially all the catalyst is available for catalytic function. A process of forming a single atom catalyst unto a porous catalyst support is also provided.

  15. Catalysts and process for liquid hydrocarbon fuel production

    Energy Technology Data Exchange (ETDEWEB)

    White, Mark G.; Ranaweera, Samantha A.; Henry, William P.

    2016-08-02

    The present invention provides a novel process and system in which a mixture of carbon monoxide and hydrogen synthesis gas, or syngas, is converted into hydrocarbon mixtures composed of high quality distillates, gasoline components, and lower molecular weight gaseous olefins in one reactor or step. The invention utilizes a novel supported bimetallic ion complex catalyst for conversion, and provides methods of preparing such novel catalysts and use of the novel catalysts in the process and system of the invention.

  16. Polymethacrylate monoliths with immobilized poly-3-mercaptopropyl methylsiloxane film for high-coverage surface functionalization by thiol-ene click reaction.

    Science.gov (United States)

    Carrasco-Correa, Enrique Javier; Ramis-Ramos, Guillermo; Herrero-Martínez, José Manuel; Lämmerhofer, Michael

    2014-11-07

    In this work, new polythiol-functionalized macroporous monolithic polymethacrylate-polysiloxane composite materials are presented which can be useful substrates for highly efficient immobilization of (chiral) catalysts, chromatographic ligands, and other functional moieties by thiol-ene click reaction. Poly(glycidyl methacrylate-co-ethylene dimethacrylate) (poly(GMA-co-EDMA)) monoliths were coated with a poly-3-mercaptopropyl methylsiloxane (PMPMS) film and subsequently the polymer was covalently immobilized by formation of crosslinks via nucleophilic substitution reaction with pendent 2,3-epoxypropyl groups on the monolith surface. This monolith, though, showed similar levels of surface coverage as a reference monolith obtained by opening of the epoxide groups with sodium hydrogen sulfide. However, a 3-step functionalization by amination of the epoxy monolith, followed by its vinylation with allylglycidyl ether and subsequent thiolation by coating of a thin polythiol (PMPMS) film and crosslinking by click reaction furnished a monolith with more than 2-fold elevated thiol coverage. Its further functionalization with a clickable chiral quinine carbamate selector clearly documented the benefit of highly dense thiol surfaces for such reactions and synthesis of functional materials with proper ligand loadings. The new monoliths were chromatographically tested in capillary electrochromatography mode using N-3,5-dinitrobenzoyl-leucine as chiral probe and the capillary column with the monolith having the highest selector coverage, produced from the precursor with the most thiols on the surface, showed the largest separation factor. By performic acid oxidation the surface characteristic could be tuned and strongly altered due to a delicate balance of enantioselective and non-specific interactions. Copyright © 2014 Elsevier B.V. All rights reserved.

  17. Catalyst Architecture

    DEFF Research Database (Denmark)

    Kiib, Hans; Marling, Gitte; Hansen, Peter Mandal

    2014-01-01

    How can architecture promote the enriching experiences of the tolerant, the democratic, and the learning city - a city worth living in, worth supporting and worth investing in? Catalyst Architecture comprises architectural projects, which, by virtue of their location, context and their combination...... of programs, have a role in mediating positive social and/or cultural development. In this sense, we talk about architecture as a catalyst for: sustainable adaptation of the city’s infrastructure appropriate renovation of dilapidated urban districts strengthening of social cohesiveness in the city development...

  18. Reactor Neutrinos

    OpenAIRE

    Soo-Bong Kim; Thierry Lasserre; Yifang Wang

    2013-01-01

    We review the status and the results of reactor neutrino experiments. Short-baseline experiments have provided the measurement of the reactor neutrino spectrum, and their interest has been recently revived by the discovery of the reactor antineutrino anomaly, a discrepancy between the reactor neutrino flux state of the art prediction and the measurements at baselines shorter than one kilometer. Middle and long-baseline oscillation experiments at Daya Bay, Double Chooz, and RENO provided very ...

  19. BOILING REACTORS

    Science.gov (United States)

    Untermyer, S.

    1962-04-10

    A boiling reactor having a reactivity which is reduced by an increase in the volume of vaporized coolant therein is described. In this system unvaporized liquid coolant is extracted from the reactor, heat is extracted therefrom, and it is returned to the reactor as sub-cooled liquid coolant. This reduces a portion of the coolant which includes vaporized coolant within the core assembly thereby enhancing the power output of the assembly and rendering the reactor substantially self-regulating. (AEC)

  20. The Application of RUF Series Catalysts and Its Grading Optimization Technology

    Institute of Scientific and Technical Information of China (English)

    Wang Changling

    2008-01-01

    Qilu Petrochemical Company in order to synchronize the replacement of catalysts in the upflow reactor (UFR) and fixed-bed reactors and achieve the 1.5-year operating cycle of the residue hydrotreating unit has revamped the UFR and optimized catalysts grading. Commercial operation results have revealed that the series of catalysts for residue hydrotreating after optimized grading achieved an operating cycle of 1.5 years with the quality of hydrotreated oil products meeting the requirements for FCC feedstock.

  1. US Progress on Property Characterization to Support LEU U-10 Mo Monolithic Fuel Development

    Energy Technology Data Exchange (ETDEWEB)

    Cole, James Irvin [Idaho National Laboratory; Rabin, Barry H [Idaho National Laboratory; Smith, James Arthur [Idaho National Laboratory; Scott, Clark Landon [Idaho National Laboratory; Benefiel, Bradley Curtis [Idaho National Laboratory; Larsen, Eric David [Idaho National Laboratory; Lind, Robert Paul [Idaho National Laboratory; Sell, David Alan [Idaho National Laboratory

    2016-03-01

    The US High Performance Research Reactor program is pursuing development and qualification of a new high density monolithic LEU fuel to facilitate conversion of five higher power research reactors located in the US (ATR, HFIR, NBSR, MIT and MURR). In order to support fabrication development and fuel performance evaluations, new testing capabilities are being developed to evaluate the properties of fuel specimens. Residual stress and fuel-cladding bond strength are two characteristics related to fuel performance that are being investigated. In this overview, new measurement capabilities being developed to assess these characteristics in both fresh and irradiated fuel are described. Progress on fresh fuel testing is summarized and on-going hot-cell implementation efforts to support future PIE campaigns are detailed. It is anticipated that benchmarking of as-fabricated fuel characteristics will be critical to establishing technical bases for specifications that optimize fuel fabrication and ensure acceptable in-reactor fuel performance.

  2. Monolithically integrated Ge CMOS laser

    Science.gov (United States)

    Camacho-Aguilera, Rodolfo

    2014-02-01

    Ge-on-Si devices are explored for photonic integration. Through the development of better growth techniques, monolithic integration, laser design and prototypes, it was possible to probe Ge light emitters with emphasis on lasers. Preliminary worked shows thermal photonic behavior capable of enhancing lamination at high temperatures. Increase luminescence is observed up to 120°C from L-band contribution. Higher temperatures show contribution from Δ -band. The increase carrier thermal contribution suggests high temperature applications for Ge light emitters. A Ge electrically pumped laser was probed under 0.2% biaxial strain and doping concentration ~4.5×1019cm-3 n-type. Ge pnn lasers exhibit a gain >1000cm-1 with 8mW power output, presenting a spectrum range of over 200nm, making Ge the ideal candidate for Si photonics. Large temperatures fluctuations and process limit the present device. Theoretically a gain of >4000cm- gain is possible with a threshold of as low as 1kA/cm2. Improvements in Ge work

  3. Fischer-Tropsch Synthesis (FTS) catalytic evaluation of a 10%Co/Nb{sub 2}O{sub 5} catalyst in a agitated slurry reactor; Avaliacao catalitica do catalisador 10%Co/Nb{sub 2}O{sub 5} na Sintese de Fischer-Tropsch (SFT) em um reator em leito de lama agitado

    Energy Technology Data Exchange (ETDEWEB)

    Castro, Gustavo P.; Meza, Lucas P.; Spigao Junior, Antonio C.S.; Soares, Ricardo R. [Universidade Federal de Uberlandia, MG (Brazil)

    2004-07-01

    The objective of this work was to evaluate the performance of a Co/Nb{sub 2}O{sub 5} catalyst in the Fischer-Tropsch Synthesis (FTS) in an agitated slurry reactor, using a methodology and reaction unit developed by the authors. Besides this, an evaluation of the reaction kinetic parameters, from the literature, was accomplished. The catalyst was prepared by the homogeneous precipitation method to obtain a cobalt content of 10 wt%. The reactions were accomplished, after ex-situ reduction, at 500 deg C, of 20 g of 10% Co/Nb{sub 2}O{sub 5} catalyst, in a 500 mL slurry reactor, loaded with 150 g of octacosane solvent (C{sub 28}H{sub 58}). The reaction temperature was varied from 180 to 220 deg C and the initial reaction mixture flow rate from 20 to 60 mL/min. The used reaction pressure was 20 bar. The selectivities were calculated by gaseous effluent chromatographic analysis, relating these effluent molar fractions with the slurry composition by an asymmetric model of the liquid - vapor equilibrium. An evaluation of the carbon chain growth probability parameter ({alpha}) was accomplished using the Anderson-Schulz-Flory products distribution model. The parameters of both kinetic models, with a possible reaction mechanism, were estimated by non linear regression analysis. The obtained results showed that the 10%Co/Nb{sub 2}O{sub 5} catalyst presented high stability within few hours of reaction, little selectivity for methane and CO{sub 2}, and high selectivity for C{sub 5+}, specially for gasoline (C{sub 5} - C{sub 11}) and diesel (C{sub 12} - C{sub 20}). The {alpha} calculated values were all grater than 0.75. The estimated parameters for both kinetic models were slightly smaller than the others cobalt catalysts parameters, from the literature. This models adjustment to the experimental data was satisfactory, showing correlation coefficients grater than 0.97. (author)

  4. Heterogeneous Catalysts

    NARCIS (Netherlands)

    Dakka, J.; Sheldon, R.A.; Sanderson, W.A.

    1997-01-01

    Abstract of GB 2309655 (A) Heterogeneous catalysts comprising one or more metal compounds selected from the group consisting of tin, molybdenum, tungsten, zirconium and selenium compounds deposited on the surface of a silicalite are provided. Preferably Sn(IV) and/or Mo(VI) are employed. The cat

  5. WATER BOILER REACTOR

    Science.gov (United States)

    King, L.D.P.

    1960-11-22

    As its name implies, this reactor utilizes an aqueous solution of a fissionable element salt, and is also conventional in that it contains a heat exchanger cooling coil immersed in the fuel. Its novelty lies in the utilization of a cylindrical reactor vessel to provide a critical region having a large and constant interface with a supernatant vapor region, and the use of a hollow sleeve coolant member suspended from the cover assembly in coaxial relation with the reactor vessel. Cool water is circulated inside this hollow coolant member, and a gap between its outer wall and the reactor vessel is used to carry off radiolytic gases for recombination in an external catalyst chamber. The central passage of the coolant member defines a reflux condenser passage into which the externally recombined gases are returned and condensed. The large and constant interface between fuel solution and vapor region prevents the formation of large bubbles and minimizes the amount of fuel salt carried off by water vapor, thus making possible higher flux densities, specific powers and power densities.

  6. Ceramic oxygen transport membrane array reactor and reforming method

    Energy Technology Data Exchange (ETDEWEB)

    Kelly, Sean M.; Christie, Gervase Maxwell; Rosen, Lee J.; Robinson, Charles; Wilson, Jamie R.; Gonzalez, Javier E.; Doraswami, Uttam R.

    2016-09-27

    A commercially viable modular ceramic oxygen transport membrane reforming reactor for producing a synthesis gas that improves the thermal coupling of reactively-driven oxygen transport membrane tubes and catalyst reforming tubes required to efficiently and effectively produce synthesis gas.

  7. Modified monolithic silica capillary for preconcentration of catecholamines

    Institute of Scientific and Technical Information of China (English)

    Wei Chang; Tusyo-shi Komazu

    2009-01-01

    Preconcentration of catecholamines by the modified monolithic silica in the capillary was investigated in this study. In order to achieve a microchip-based method for determining catecholamines in the saliva, the monolithic silica was fabricated in the capillary and the monolithic silica was chemically modified by on-column reaction with phenylboronate. Different modified methods were compared. The concentration conditions were optimized. This study indicates the applicability of the modified monolithic silica capillary when it was used to concentrate catecholamines.

  8. Modified monolithic silica capillary for preconcentration of catecholamines

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Preconcentration of catecholamines by the modified monolithic silica in the capillary was investigated in this study. In order to achieve a microchip-based method for determining catecholamines in the saliva,the monolithic silica was fabricated in the capillary and the monolithic silica was chemically modified by on-column reaction with phenylboronate. Different modified methods were compared. The concentration conditions were optimized. This study indicates the applicability of the modified monolithic sili...

  9. Fracture resistance of monolithic zirconia molar crowns with reduced thickness

    OpenAIRE

    Nakamura, Keisuke; Harada, A.; Inagaki, R.; Kanno, Taro; Niwano, Y; Milleding, Percy; Ørtengren, Ulf Thore

    2015-01-01

    This is the accepted manuscript version. Published version is available at Acta Odontologica Scandinavica Objectives. The purpose of the present study was to analyze the relationship between fracture load of monolithic zirconia crowns and axial/occlusal thickness, and to evaluate the fracture resistance of monolithic zirconia crowns with reduced thickness in comparison with that of monolithic lithium disilicate crowns with regular thickness. Materials and methods. Monolithic zi...

  10. Development of a monolithic ferrite memory array

    Science.gov (United States)

    Heckler, C. H., Jr.; Bhiwandker, N. C.

    1972-01-01

    The results of the development and testing of ferrite monolithic memory arrays are presented. This development required the synthesis of ferrite materials having special magnetic and physical characteristics and the development of special processes; (1) for making flexible sheets (laminae) of the ferrite composition, (2) for embedding conductors in ferrite, and (3) bonding ferrite laminae together to form a monolithic structure. Major problems encountered in each of these areas and their solutions are discussed. Twenty-two full-size arrays were fabricated and fired during the development of these processes. The majority of these arrays were tested for their memory characteristics as well as for their physical characteristics and the results are presented. The arrays produced during this program meet the essential goals and demonstrate the feasibility of fabricating monolithic ferrite memory arrays by the processes developed.

  11. Eigenpolarization theory of monolithic nonplanar ring oscillators

    Science.gov (United States)

    Nilsson, Alan C.; Gustafson, Eric K.; Byer, Robert L.

    1989-01-01

    Diode-laser-pumped monolithic nonplanar ring oscillators (NPROs) in an applied magnetic field can operate as unidirectional traveling-wave lasers. The diode laser pumping, monolithic construction, and unidirectional oscillation lead to narrow linewidth radiation. Here, a comprehensive theory of the eigenpolarizations of a monolithic NPRO is presented. It is shown how the properties of the integral optical diode that forces unidirectional operation depend on the choice of the gain medium, the applied magnetic field, the output coupler, and the geometry of the nonplanar ring light path. Using optical equivalence theorems to gain insight into the polarization characteristics of the NPRO, a strategy for designing NPROs with low thresholds and large loss nonreciprocities is given. An analysis of the eigenpolarizations for one such NPRO is presented, alternative optimization approaches are considered, and the prospects for further reducing the linewidths of these lasers are briefly discussed.

  12. Deactivation of platinum catalysts by oxygen 2. Nature of the catalyst deactivation

    Energy Technology Data Exchange (ETDEWEB)

    Dijkgraaf, P.J.M.; Duisters, H.A.M.; Kuster, B.F.M.; van der Wiele, K. (Univ. of Technology, Eindhoven (Netherlands))

    1988-08-01

    The effect of different start-up procedures on the deactivation of a 5% Pt/C catalyst used for the oxidation of D-gluconate has been investigated. Results have been obtained both in a stirred tank reactor for batch experiments and in an apparatus for continuous oxidation processes. The deactivation of the catalyst is not explicable by formation of platinum oxides. A model is proposed for the deactivation of platinum catalysts by oxygen, based on penetration of oxygen atoms into the platinum lattice.

  13. µ-reactors for Heterogeneous Catalysis

    DEFF Research Database (Denmark)

    Jensen, Robert

    catalyst surface area by reacting off an adsorbed layer of oxygen with CO. This procedure can be performed at temperatures low enough that sintering of Pt nanoparticles is not an issue. Some results from the reactors are presented. In particular an unexpected oscillation phenomenon of CO-oxidation on Pt...... nanoparticles are presented in detail. The sensitivity of the reactors are currently being investigated with CO oxidation on Pt thin films as a test reaction, and the results so far are presented. We have at this point shown that we are able to reach full conversion with a catalyst area of 38 µm2 with a turn......This thesis is the summary of my work on the µ-reactor platform. The concept of µ-reactors is presented and some of the experimental challenges are outlined. The various experimental issues regarding the platform are discussed and the actual implementation of three generations of the setup...

  14. Physical and chemical sensing using monolithic semiconductor optical transducers

    Science.gov (United States)

    Zappe, Hans P.; Hofstetter, Daniel; Maisenhoelder, Bernd; Moser, Michael; Riel, Peter; Kunz, Rino E.

    1997-09-01

    We present two monolithically integrated optical sensor systems based on semiconductor photonic integrated circuits. These compact, robust and highly functional transducers perform all necessary optical and electro-optical functions on-chip; extension to multi-sensor arrays is easily envisaged. A monolithic Michelson interferometer for high-resolution displacement measurement and a monolithic Mach-Zehnder interferometer for refractometry are discussed.

  15. Increased thermal conductivity monolithic zeolite structures

    Science.gov (United States)

    Klett, James; Klett, Lynn; Kaufman, Jonathan

    2008-11-25

    A monolith comprises a zeolite, a thermally conductive carbon, and a binder. The zeolite is included in the form of beads, pellets, powders and mixtures thereof. The thermally conductive carbon can be carbon nano-fibers, diamond or graphite which provide thermal conductivities in excess of about 100 W/mK to more than 1,000 W/mK. A method of preparing a zeolite monolith includes the steps of mixing a zeolite dispersion in an aqueous colloidal silica binder with a dispersion of carbon nano-fibers in water followed by dehydration and curing of the binder is given.

  16. Monolithically integrated optoelectronic down-converter (MIOD)

    Science.gov (United States)

    Portnoi, Efrim L.; Venus, G. B.; Khazan, A. A.; Gorfinkel, Vera B.; Kompa, Guenter; Avrutin, Evgenii A.; Thayne, Iain G.; Barrow, David A.; Marsh, John H.

    1995-06-01

    Optoelectronic down-conversion of very high-frequency amplitude-modulated signals using a semiconductor laser simultaneously as a local oscillator and a mixer is proposed. Three possible constructions of a monolithically integrated down-converter are considered theoretically: a four-terminal semiconductor laser with dual pumping current/modal gain control, and both a passively mode-locked and a passively Q-switched semiconductor laser monolithically integrated with an electroabsorption or pumping current modulator. Experimental verification of the feasibility of the concept of down conversion in a laser diode is presented.

  17. Preparation and Cracking Performance of FCC Co-Catalyst for Enhancing Light Oil Production

    Institute of Scientific and Technical Information of China (English)

    Wu Feiyue; Shi Li; Weng Huixin; Wang Xin

    2008-01-01

    In this paper,a FCC co-catalyst for enhancing the light oil production was prepared by the sol-gel method,and its effect on the performance of residue cracking catalysts was evaluated in a CCFFB reactor.The test results indicated that the liquid product yield increased obviously,after the surface of FCC equilibrium catalyst was impregnated with the co-catalyst.The yields of dry gas,slurry and coke decreased,while the diesel yield changed slightly.And the crackability of residue was increased; the rate of coke deposition on catalyst surface was decreased,with the thermal cracking reactions inhibited.All these results showed that the co-catalyst could improve the density of acid sites and change the catalyst acidity,which could promote to prolong the catalyst activity by depositing the co-catalyst on the surface of FCC equilibrium catalysts.

  18. Degradation of orange dyes and carbamazepine by soybean peroxidase immobilized on silica monoliths and titanium dioxide.

    Science.gov (United States)

    Calza, Paola; Zacchigna, Dario; Laurenti, Enzo

    2016-12-01

    In this paper, the removal of three common dyes (orange I, orange II, and methylorange) and of the anticonvulsant drug carbamazepine from aqueous solutions by means of enzymatic and photocatalytic treatment was studied. Soybean peroxidase (SBP) was used as biocatalyst, both free in solution and immobilized on silica monoliths, and titanium dioxide as photocatalyst. The combination of the two catalysts led to a faster (about two to four times) removal of all the orange dyes compared to the single systems. All the dyes were completely removed within 2 h, also in the presence of immobilized SBP. As for carbamazepine, photocatalytic treatment prevails on the enzymatic degradation, but the synergistic effect of two catalysts led to a more efficient degradation; carbamazepine's complete disappearance was achieved within 60 min with combined system, while up to 2 h is required with TiO2 only.

  19. Acrylic acid and electric power cogeneration in an SOFC reactor.

    Science.gov (United States)

    Ji, Baofeng; Wang, Jibo; Chu, Wenling; Yang, Weishen; Lin, Liwu

    2009-04-21

    A highly efficient catalyst, MoV(0.3)Te(0.17)Nb(0.12)O, used for acrylic acid (AA) production from propane, was used as an anodic catalyst in an SOFC reactor, from which AA and electric power were cogenerated at 400-450 degrees C.

  20. Catalysts and process for liquid hydrocarbon fuel production

    Science.gov (United States)

    White, Mark G; Liu, Shetian

    2014-12-09

    The present invention provides a novel process and system in which a mixture of carbon monoxide and hydrogen synthesis gas, or syngas, is converted into hydrocarbon mixtures composed of high quality gasoline components, aromatic compounds, and lower molecular weight gaseous olefins in one reactor or step. The invention utilizes a novel molybdenum-zeolite catalyst in high pressure hydrogen for conversion, as well as a novel rhenium-zeolite catalyst in place of the molybdenum-zeolite catalyst, and provides for use of the novel catalysts in the process and system of the invention.

  1. Conversion of Biomass Syngas to DME Using a Microchannel Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Jianli; Wang, Yong; Cao, Chunshe; Elliott, Douglas C.; Stevens, Don J.; White, James F.

    2005-03-01

    The capability of a microchannel reactor for direct synthesis of dimethylether (DME) from biomass syngas was explored. The reactor was operated in conjunction with a hybrid catalyst system consisting of methanol synthesis and dehydration catalysts, and the influence of reaction parameters on syngas conversion was investigated. The activities of different dehydration catalysts were compared under DME synthesis conditions. Reaction temperature and pressure exhibited similar positive effects on DME formation. A catalytic stability test of the hybrid catalyst system was performed for 880 hours, during which CO conversion only decreased from 88% to 81%. In the microchannel reactor, the catalyst deactivation rate appeared to be much slower than in a tubular fixed-bed reactor tested for comparison. Test results also indicated that the dehydration reaction rate and the water depletion rate via a water-gas-shift reaction should be compatible in order to achieve high selectivity to DME. Using the microchannel reactor, it was possible to achieve a space time yield almost three times higher than commercially demonstrated performance results. A side-by-side comparison indicated that the heat removal capability of the microchannel reactor was at least six times greater than that of a commercial slurry reactor under similar reaction conditions.

  2. Monolithic Integration of GaN-based LEDs

    Energy Technology Data Exchange (ETDEWEB)

    Ao, Jin-Ping, E-mail: jpao@ee.tokushima-u.ac.jp [Institute of Technology and Science, University of Tokushima 2-1 Minami-Josanjima, Tokushima 770-8506 (Japan)

    2011-02-01

    The technology of monolithically integrated GaN-based light-emitting diodes (LEDs) is reported. First, the technology details to realize monolithic integration are described, including the circuit design for high-voltage and alternating current (AC) operation and the technologies for device isolation. The performances of the fabricated monolithic LED arrays are then demonstrated. A monolithic series array with totally 40 LEDs exhibited expected operation function under AC bias. The operation voltage of the array is 72 V when 20 LEDs were connected in series. Some modified circuit designs for high-voltage operation and other monolithic LED arrays are finally reviewed.

  3. Monolithic resonant optical reflector laser diodes

    Science.gov (United States)

    Hirata, T.; Suehiro, M.; Maeda, M.; Hihara, M.; Hosomatsu, H.

    1991-10-01

    The first monolithic resonant optical reflector laser diode that has a waveguide directional coupler and two DBR reflectors integrated by compositional disordering of quantum-well heterostructures is described. A linewidth of 440 kHz was obtained, and this value is expected to be greatly decreased by reducing the propagation loss in the integrated waveguide.

  4. Constant capacitance in nanopores of carbon monoliths.

    Science.gov (United States)

    García-Gómez, Alejandra; Moreno-Fernández, Gelines; Lobato, Belén; Centeno, Teresa A

    2015-06-28

    The results obtained for binder-free electrodes made of carbon monoliths with narrow micropore size distributions confirm that the specific capacitance in the electrolyte (C2H5)4NBF4/acetonitrile does not depend significantly on the micropore size and support the foregoing constant result of 0.094 ± 0.011 F m(-2).

  5. Hierarchical porous nitrogen-doped partial graphitized carbon monoliths for supercapacitor

    Science.gov (United States)

    Yu, Yifeng; Du, Juan; Liu, Lei; Wang, Guoxu; Zhang, Hongliang; Chen, Aibing

    2017-03-01

    Porous carbon monoliths have attracted great interest in many fields due to their easy availability, large specific surface area, desirable electronic conductivity, and tunable pore structure. In this work, hierarchical porous nitrogen-doped partial graphitized carbon monoliths (N-MC-Fe) with ordered mesoporous have been successfully synthesized by using resorcinol-formaldehyde as precursors, iron salts as catalyst, and mixed triblock copolymers as templates via a one-step hydrothermal method. In the reactant system, hexamethylenetetramine (HMT) is used as nitrogen source and one of the carbon precursors under hydrothermal conditions instead of using toxic formaldehyde. The N-MC-Fe show hierarchically porous structures, with interconnected macroporous and ordered hexagonally arranged mesoporous. Nitrogen element is in situ doped into carbon through decomposition of HMT. Iron catalyst is helpful to improve the graphitization degree and pore volume of N-MC-Fe. The synthesis strategy is user-friendly, cost-effective, and can be easily scaled up for production. As supercapacitors, the N-MC-Fe show good capacity with high specific capacitance and good electrochemical stability.

  6. Catalyst Architecture

    DEFF Research Database (Denmark)

    Kiib, Hans; Marling, Gitte; Hansen, Peter Mandal

    2014-01-01

    of programs, have a role in mediating positive social and/or cultural development. In this sense, we talk about architecture as a catalyst for: sustainable adaptation of the city’s infrastructure appropriate renovation of dilapidated urban districts strengthening of social cohesiveness in the city development...... meaningful for everyone. The exhibited works are designed by SANAA, Diller Scofidio + Renfro, James Corner Field Operation, JBMC Arquitetura e Urbanismo, Atelier Bow-Wow, Ateliers Jean Nouvel, COBE, Transform, BIG, Topotek1, Superflex, and by visual artist Jane Maria Petersen....

  7. Multifunctional reactors

    NARCIS (Netherlands)

    Westerterp, K.R.

    1992-01-01

    Multifunctional reactors are single pieces of equipment in which, besides the reaction, other functions are carried out simultaneously. The other functions can be a heat, mass or momentum transfer operation and even another reaction. Multifunctional reactors are not new, but they have received much

  8. Synthesis of monolithic graphene – graphite integrated electronics

    Science.gov (United States)

    Park, Jang-Ung; Nam, SungWoo; Lee, Mi-Sun; Lieber, Charles M.

    2013-01-01

    Encoding electronic functionality into nanoscale elements during chemical synthesis has been extensively explored over the past decade as the key to developing integrated nanosystems1 with functions defined by synthesis2-6. Graphene7-12 has been recently explored as a two-dimensional nanoscale material, and has demonstrated simple device functions based on conventional top-down fabrication13-20. However, the synthetic approach to encoding electronic functionality and thus enabling an entire integrated graphene electronics in a chemical synthesis had not previously been demonstrated. Here we report an unconventional approach for the synthesis of monolithically-integrated electronic devices based on graphene and graphite. Spatial patterning of heterogeneous catalyst metals permits the selective growth of graphene and graphite, with controlled number of graphene layers. Graphene transistor arrays with graphitic electrodes and interconnects were formed from synthesis. These functional, all-carbon structures were transferrable onto a variety of substrates. The integrated transistor arrays were used to demonstrate real-time, multiplexed chemical sensing, and more significantly, multiple carbon layers of the graphene-graphite device components were vertically assembled to form a three-dimensional flexible structure which served as a top-gate transistor array. These results represent a substantial progress towards encoding electronic functionality via chemical synthesis and suggest future promise for one-step integration of graphene-graphite based electronics. PMID:22101813

  9. Synthesis of monolithic graphene-graphite integrated electronics.

    Science.gov (United States)

    Park, Jang-Ung; Nam, SungWoo; Lee, Mi-Sun; Lieber, Charles M

    2011-11-20

    Encoding electronic functionality into nanoscale elements during chemical synthesis has been extensively explored over the past decade as the key to developing integrated nanosystems with functions defined by synthesis. Graphene has been recently explored as a two-dimensional nanoscale material, and has demonstrated simple device functions based on conventional top-down fabrication. However, the synthetic approach to encoding electronic functionality and thus enabling an entire integrated graphene electronics in a chemical synthesis had not previously been demonstrated. Here we report an unconventional approach for the synthesis of monolithically integrated electronic devices based on graphene and graphite. Spatial patterning of heterogeneous metal catalysts permits the selective growth of graphene and graphite, with a controlled number of graphene layers. Graphene transistor arrays with graphitic electrodes and interconnects were formed from the synthesis. These functional, all-carbon structures were transferable onto a variety of substrates. The integrated transistor arrays were used to demonstrate real-time, multiplexed chemical sensing and more significantly, multiple carbon layers of the graphene-graphite device components were vertically assembled to form a three-dimensional flexible structure which served as a top-gate transistor array. These results represent substantial progress towards encoding electronic functionality through chemical synthesis and suggest the future promise of one-step integration of graphene-graphite based electronics.

  10. A novel reverse flow reactor coupling endothermic and exothermic reactions. Part I: comparison of reactor configurations for irreversible endothermic reactions

    NARCIS (Netherlands)

    van Sint Annaland, M.; Scholts, H.A.R.; Kuipers, J.A.M.; van Swaaij, Willibrordus Petrus Maria

    2002-01-01

    A new reactor concept is studied for highly endothermic heterogeneously catalysed gas phase reactions at high temperatures with rapid but reversible catalyst deactivation. The reactor concept aims to achieve an indirect coupling of energy necessary for endothermic reactions and energy released by

  11. Co-Production of Electricity and Hydrogen Using a Novel Iron-based Catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Hilaly, Ahmad; Georgas, Adam; Leboreiro, Jose; Arora, Salil; Head, Megann; Trembly, Jason; Turk, Brian; Gupta, Raghubir

    2011-09-30

    The primary objective of this project was to develop a hydrogen production technology for gasification applications based on a circulating fluid-bed reactor and an attrition resistant iron catalyst. The work towards achieving this objective consisted of three key activities: • Development of an iron-based catalyst suitable for a circulating fluid-bed reactor • Design, construction, and operation of a bench-scale circulating fluid-bed reactor system for hydrogen production • Techno-economic analysis of the steam-iron and the pressure swing adsorption hydrogen production processes. This report describes the work completed in each of these activities during this project. The catalyst development and testing program prepared and iron-based catalysts using different support and promoters to identify catalysts that had sufficient activity for cyclic reduction with syngas and steam oxidation and attrition resistance to enable use in a circulating fluid-bed reactor system. The best performing catalyst from this catalyst development program was produced by a commercial catalyst toll manufacturer to support the bench-scale testing activities. The reactor testing systems used during material development evaluated catalysts in a single fluid-bed reactor by cycling between reduction with syngas and oxidation with steam. The prototype SIP reactor system (PSRS) consisted of two circulating fluid-bed reactors with the iron catalyst being transferred between the two reactors. This design enabled demonstration of the technical feasibility of the combination of the circulating fluid-bed reactor system and the iron-based catalyst for commercial hydrogen production. The specific activities associated with this bench-scale circulating fluid-bed reactor systems that were completed in this project included design, construction, commissioning, and operation. The experimental portion of this project focused on technical demonstration of the performance of an iron-based catalyst and a

  12. Methanol synthesis in a countercurrent gas-solid-solid trickle flow reactor. An experimental study

    NARCIS (Netherlands)

    Kuczynski, M.; Oyevaar, M.H.; Pieters, R.T.; Westerterp, K.R.

    1987-01-01

    The synthesis of methanol from CO and H2 was executed in a gas-solid-solid trickle flow reactor. The reactor consisted of three tubular reactor sections with cooling sections in between. The catalyst was Cu on alumina, the adsorbent was a silica-alumina powder and the experimental range 498–523 K,

  13. Decoupling HZSM-5 catalyst activity from deactivation during upgrading of pyrolysis oil vapors.

    Science.gov (United States)

    Wan, Shaolong; Waters, Christopher; Stevens, Adam; Gumidyala, Abhishek; Jentoft, Rolf; Lobban, Lance; Resasco, Daniel; Mallinson, Richard; Crossley, Steven

    2015-02-01

    The independent evaluation of catalyst activity and stability during the catalytic pyrolysis of biomass is challenging because of the nature of the reaction system and rapid catalyst deactivation that force the use of excess catalyst. In this contribution we use a modified pyroprobe system in which pulses of pyrolysis vapors are converted over a series of HZSM-5 catalysts in a separate fixed-bed reactor controlled independently. Both the reactor-bed temperature and the Si/Al ratio of the zeolite are varied to evaluate catalyst activity and deactivation rates independently both on a constant surface area and constant acid site basis. Results show that there is an optimum catalyst-bed temperature for the production of aromatics, above which the production of light gases increases and that of aromatics decrease. Zeolites with lower Si/Al ratios give comparable initial rates for aromatics production, but far more rapid catalyst deactivation rates than those with higher Si/Al ratios.

  14. Laboratory evaluation of FCC commercial catalysts. Analysis of products of industrial importance

    Energy Technology Data Exchange (ETDEWEB)

    Passamonti, Francisco J.; De la Puente, Gabriela; Sedran, Ulises [Instituto de Investigaciones en Catalisis y Petroquimica (INCAPE, FIQ, UNL-CONICET), Santiago del Estero 2654, 3000 Santa Fe (Argentina)

    2008-04-15

    The results of the conversion of a VGO over six equilibrium commercial FCC catalysts with different formulations in a batch CREC Riser Simulator laboratory reactor at 500 and 550 C, catalyst to oil ratio 6.1 and reaction times from 3 to 30 s, were analyzed. It was possible to define the main catalyst characteristics in terms of various evaluation items, such as activity, gasoline yield and quality, LPG yield and coke yield, or the yields of particular compounds like, e.g., isobutane. Important differences in activity between catalysts were not observed, but catalyst properties reflected clearly as significant differences in gasoline, LPG or coke selectivities. Particularly, catalyst's hydrogen transfer properties impacted on gasoline composition and isobutane yield. The results showed that the CREC Riser Simulator reactor is an important tool for the evaluation of both commercial catalysts and feedstocks and process conditions. (author)

  15. Stability and resistance of nickel catalysts for hydrodeoxygenation

    DEFF Research Database (Denmark)

    Mortensen, Peter Mølgaard; Gardini, Diego; de Carvalho, Hudson W. P.;

    2014-01-01

    of activity. Analysis of the spent catalyst revealed that the adsorption of chlorine on the catalyst was completely reversible, but chlorine had caused sintering of nickel particles. In two experiments, potassium, as either KCl or KNO3, was impregnated on the catalyst prior to testing. In both cases......The long term stability and resistance toward carbon deposition, sulfur, chlorine, and potassium of Ni/ZrO2 as a catalyst for the hydrodeoxygenation (HDO) of guaiacol in 1-octanol (as a model compound system for bio-oil) has been investigated at 250 degrees C and 100 bar in a trickle bed reactor...... setup. Without impurities in the feed good stability of the Ni/ZrO2 catalyst could be achieved over more than 100 h of operation, particularly for a sample prepared with small Ni particles, which minimized carbon deposition. Exposing the catalyst to 0.05 wt% sulfur in the feed resulted in rapid...

  16. Reactor for Photocatalytic Degradation of Chloroform

    DEFF Research Database (Denmark)

    Simonsen, Morten Enggrob; Søgaard, Erik Gydesen

    In the present study a new type of continuous photoreactor is developed in which the TiO2 catalyst is immobilized on the surface of quartz tubes surrounding the UV lamps and on the internal surface of the reactor walls. The study showed that an initial concentration chloroform of 7 mg/l was degra...

  17. Coupled Transport Phenomena in Corrugated Photocatalytic Reactors

    Institute of Scientific and Technical Information of China (English)

    Adam A. Donaldson; ZHANG Zisheng

    2011-01-01

    Corrugated reactors are known for their use in applications requiring UV-exposure, whereby media flowing within the corrugated channel react with a photo-active catalyst impregnated on the surface (i.e. TiO2). The performance in these systems is dependent on catalyst properties and reactivity for a given light source, in conjunc-tion with the coupled transport of reactants within the media and photons falling incident to the catalyst surface. Experimental and computational analyses of local mass transfer and radiation pattems for a broad range of corrugation angles, depths, and non-idealities introduced during manufacture (i.e. fold curvature) are thus integrated to the design and optimization of these systems. This work explores techniques for determining incident energy distribu-tions on the surface of corrugated reactor geometries with non-ideal cross-sectional profiles, and the local and overall mass transfer rates obtained using computational fluid dynamics and experimental analysis. By examining the reaction kinetics for the photo-degradation of 4-chlorophenol over a TiO2 catalyst, the effects of surface area, energy incidence with photon recapture, and local mass transfer on overall reactor performance are presented to highlight ootimization concerns for these tvoes of reactors.

  18. Physical properties of monolithic U8 wt.%-Mo

    Science.gov (United States)

    Hengstler, R. M.; Beck, L.; Breitkreutz, H.; Jarousse, C.; Jungwirth, R.; Petry, W.; Schmid, W.; Schneider, J.; Wieschalla, N.

    2010-07-01

    As a possible high density fuel for research reactors, monolithic U8 wt.%-Mo ("U8Mo") was examined with regard to its structural, thermal and electric properties. X-ray diffraction by the Bragg-Brentano method was used to reveal the tetragonal lattice structure of rolled U8Mo. The specific heat capacity of cast U8Mo was determined by differential scanning calorimetry, its thermal diffusivity was measured by the laser flash method and its mass density by Archimedes' principle. From these results, the thermal conductivity of U8Mo in the temperature range from 40 °C to 250 °C was calculated; in the measured temperature range, it is in good accordance with literature data for UMo with 8 and 9 wt.% Mo, is higher than for 10 wt.% Mo and lower than for 5 wt.% Mo. The electric conductivity of rolled and cast U8Mo was measured by a four-wire method and the electron based part of the thermal conductivity calculated by the Wiedemann-Frantz law. Rolled and cast U8Mo was irradiated at about 150 °C with 80 MeV 127I ions to receive the same iodine ion density in the damage peak region as the fission product density in the fuel of a typical high flux reactor after the targeted nuclear burn-up. XRD analysis of irradiated U8Mo showed a change of the lattice parameters as well as the creation of UO 2 in the superficial sample regions; however, a phase change by irradiation was not observed. The determination of the electron based part of the thermal conductivity of the irradiated samples failed due to high measurement errors which are caused by the low thickness of the damage region in the ion irradiated samples.

  19. A nanoliter-scale open chemical reactor.

    Science.gov (United States)

    Galas, Jean-Christophe; Haghiri-Gosnet, Anne-Marie; Estévez-Torres, André

    2013-02-01

    An open chemical reactor is a container that exchanges matter with the exterior. Well-mixed open chemical reactors, called continuous stirred tank reactors (CSTR), have been instrumental for investigating the dynamics of out-of-equilibrium chemical processes, such as oscillations, bistability, and chaos. Here, we introduce a microfluidic CSTR, called μCSTR, that reduces reagent consumption by six orders of magnitude. It consists of an annular reactor with four inlets and one outlet fabricated in PDMS using multi-layer soft lithography. A monolithic peristaltic pump feeds fresh reagents into the reactor through the inlets. After each injection the content of the reactor is continuously mixed with a second peristaltic pump. The efficiency of the μCSTR is experimentally characterized using a bromate, sulfite, ferrocyanide pH oscillator. Simulations accounting for the digital injection process are in agreement with experimental results. The low consumption of the μCSTR will be advantageous for investigating out-of-equilibrium dynamics of chemical processes involving biomolecules. These studies have been scarce so far because a miniaturized version of a CSTR was not available.

  20. Catalyst Architecture

    DEFF Research Database (Denmark)

    the projects as case studies, which contribute with strategic knowledge rather than generalizing from average considerations. These are ‘strategic projects’ where we have looked for the specific and the particular (Flyvbjerg 1991). According to the case studies, we use the case study method developed by Bent......’ interpretations and architectural strategies are included in the analyses. This implies that there is a large variation of empirical knowledge about the selected problems. That is the reason why we give a short introduction to the exact use of approaches and methods in the beginning of each case study. Based...... in experience? Which design qualities do the best examples of architecture as urban catalysts have, and how can we as citizens, politicians and professionals use knowledge about this in the development of our cities as good places to live? We wish to throw light on these key questions through case studies...

  1. Experimental and Numerical Evaluation of the By-Pass Flow in a Catalytic Plate Reactor for Hydrogen Production

    DEFF Research Database (Denmark)

    Sigurdsson, Haftor Örn; Kær, Søren Knudsen

    2011-01-01

    Numerical and experimental study is performed to evaluate the reactant by-pass flow in a catalytic plate reactor with a coated wire mesh catalyst for steam reforming of methane for hydrogen generation. By-pass of unconverted methane is evaluated under different wire mesh catalyst width to reactor...

  2. NiO@SiO2 core-shell catalyst for low-temperature methanation of syngas in slurry reactor%NiO@SiO2核壳催化剂在浆态床中低温甲烷化研究

    Institute of Scientific and Technical Information of China (English)

    王辉; 张俊峰; 白云星; 王文峰; 谭猗生; 韩怡卓

    2016-01-01

    采用改进的StÖber方法,可控制备出具有不同形貌的NiO@SiO2核壳结构催化剂,并在浆态床反应器(320℃)上,对其合成气低温甲烷化性能进行评价;同时借助XRD、TEM、XPS和N2物理吸附等方法对反应前后催化剂的物化性质进行了表征。研究表明,实验制备的催化剂形貌规整、粒径均匀,且具有较好的热稳定性。在相同的制备条件下,核颗粒粒径增大,其SiO2壳层的厚度随之增加。在反应过程中,部分催化剂的核壳结构遭到破坏并出现SiO2空壳,是CO与壳层内的Ni作用生成易迁移的Ni羰基化物种( Ni( CO) x )所致。催化剂的甲烷化活性随着核颗粒粒径的增加呈现下降趋势;在不同的反应阶段,催化剂的失活速率存在明显差异,在反应的前20 h内,催化剂出现快速失活,20 h后失活缓慢,但是催化剂的甲烷选择性都保持在80%左右。催化剂的失活,一方面,是因为反应过程中,Ni核颗粒发生了长大;另一方面,是由于壳层中3-5 nm的介孔的减少以及催化剂比表面积、孔容的下降。%A series of NiO@SiO2 core-shell catalysts were prepared using modified St?ber-method. Their catalytic performances in methanation of syngas were investigated in slurry reactor at 320℃. The catalysts before and after reaction were characterized by XRD, TEM, XPS, N2-physisorption, etc. It was found that the NiO@SiO2 core-shell samples had well-shape morphologies and relatively uniform scale. The catalyst test revealed that the methanation activity of these catalysts decreased dramatically with increase of core particle size. The three catalysts with distinct size of core and shell showed remarkably rapid deactivation in the initial period of 20 h and then deactivated slowly during the following reaction, while their CH4 selectivity maintained at about 80%. Void-shell was formed during the reaction probably because easy-migrated Ni ( CO ) x species were generated. Apparently, it was

  3. Chemical Reactors.

    Science.gov (United States)

    Kenney, C. N.

    1980-01-01

    Describes a course, including content, reading list, and presentation on chemical reactors at Cambridge University, England. A brief comparison of chemical engineering education between the United States and England is also given. (JN)

  4. Reactor Neutrinos

    Directory of Open Access Journals (Sweden)

    Soo-Bong Kim

    2013-01-01

    Full Text Available We review the status and the results of reactor neutrino experiments. Short-baseline experiments have provided the measurement of the reactor neutrino spectrum, and their interest has been recently revived by the discovery of the reactor antineutrino anomaly, a discrepancy between the reactor neutrino flux state of the art prediction and the measurements at baselines shorter than one kilometer. Middle and long-baseline oscillation experiments at Daya Bay, Double Chooz, and RENO provided very recently the most precise determination of the neutrino mixing angle θ13. This paper provides an overview of the upcoming experiments and of the projects under development, including the determination of the neutrino mass hierarchy and the possible use of neutrinos for society, for nonproliferation of nuclear materials, and geophysics.

  5. NUCLEAR REACTOR

    Science.gov (United States)

    Miller, H.I.; Smith, R.C.

    1958-01-21

    This patent relates to nuclear reactors of the type which use a liquid fuel, such as a solution of uranyl sulfate in ordinary water which acts as the moderator. The reactor is comprised of a spherical vessel having a diameter of about 12 inches substantially surrounded by a reflector of beryllium oxide. Conventionnl control rods and safety rods are operated in slots in the reflector outside the vessel to control the operation of the reactor. An additional means for increasing the safety factor of the reactor by raising the ratio of delayed neutrons to prompt neutrons, is provided and consists of a soluble sulfate salt of beryllium dissolved in the liquid fuel in the proper proportion to obtain the result desired.

  6. Reactor Engineering

    Science.gov (United States)

    Lema, Juan M.; López, Carmen; Eibes, Gemma; Taboada-Puig, Roberto; Moreira, M. Teresa; Feijoo, Gumersindo

    In this chapter, the engineering aspects of processes catalyzed by peroxidases will be presented. In particular, a discussion of the existing technologies that utilize peroxidases for different purposes, such as the removal of recalcitrant compounds or the synthesis of polymers, is analyzed. In the first section, the essential variables controlling the process will be investigated, not only those that are common in any enzymatic system but also those specific to peroxidative reactions. Next, different reactor configurations and operational modes will be proposed, emphasizing their suitability and unsuitability for different systems. Finally, two specific reactors will be described in detail: enzymatic membrane reactors and biphasic reactors. These configurations are especially valuable for the treatment of xenobiotics with high and poor water solubility, respectively.

  7. A monolithic integrated photonic microwave filter

    Science.gov (United States)

    Fandiño, Javier S.; Muñoz, Pascual; Doménech, David; Capmany, José

    2016-12-01

    Meeting the increasing demand for capacity in wireless networks requires the harnessing of higher regions in the radiofrequency spectrum, reducing cell size, as well as more compact, agile and power-efficient base stations that are capable of smoothly interfacing the radio and fibre segments. Fully functional microwave photonic chips are promising candidates in attempts to meet these goals. In recent years, many integrated microwave photonic chips have been reported in different technologies. To the best of our knowledge, none has monolithically integrated all the main active and passive optoelectronic components. Here, we report the first demonstration of a tunable microwave photonics filter that is monolithically integrated into an indium phosphide chip. The reconfigurable radiofrequency photonic filter includes all the necessary elements (for example, lasers, modulators and photodetectors), and its response can be tuned by means of control electric currents. This is an important step in demonstrating the feasibility of integrated and programmable microwave photonic processors.

  8. Macroporous Monolithic Polymers: Preparation and Applications

    Directory of Open Access Journals (Sweden)

    Cecilia Inés Alvarez Igarzabal

    2009-12-01

    Full Text Available In the last years, macroporous monolithic materials have been introduced as a new and useful generation of polymers used in different fields. These polymers may be prepared in a simple way from a homogenous mixture into a mold and contain large interconnected pores or channels allowing for high flow rates at moderate pressures. Due to their porous characteristics, they could be used in different processes, such as stationary phases for different types of chromatography, high-throughput bioreactors and in microfluidic chip applications. This review reports the contributions of several groups working in the preparation of different macroporous monoliths and their modification by immobilization of specific ligands on the products for specific purposes.

  9. Monolithic pixel detectors for high energy physics

    CERN Document Server

    Snoeys, W

    2013-01-01

    Monolithic pixel detectors integrating sensor matrix and readout in one piece of silicon have revolutionized imaging for consumer applications, but despite years of research they have not yet been widely adopted for high energy physics. Two major requirements for this application, radiation tolerance and low power consumption, require charge collection by drift for the most extreme radiation levels and an optimization of the collected signal charge over input capacitance ratio ( Q / C ). It is shown that monolithic detectors can achieve Q / C for low analog power consumption and even carryout the promise to practically eliminate analog power consumption, but combining suf fi cient Q / C , collection by drift, and integration of readout circuitry within the pixel remains a challenge. An overview is given of different approaches to address this challenge, with possible advantages and disadvantages.

  10. Reactor Neutrinos

    OpenAIRE

    Lasserre, T.; Sobel, H.W.

    2005-01-01

    We review the status and the results of reactor neutrino experiments, that toe the cutting edge of neutrino research. Short baseline experiments have provided the measurement of the reactor neutrino spectrum, and are still searching for important phenomena such as the neutrino magnetic moment. They could open the door to the measurement of coherent neutrino scattering in a near future. Middle and long baseline oscillation experiments at Chooz and KamLAND have played a relevant role in neutrin...

  11. Development and process evaluation of improved Fischer-Tropsch slurry catalysts. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Bukur, D.B.; Mukesh, D.; Patel, S.A.; Zimmerman, W.H.; Rosynek, M.P. [Texas A& M Univ., College Station, TX (United States); Kellogg, L.J. [Air Products and Chemicals, Inc., Allentown, PA (United States)

    1990-04-01

    This report describes results of a study aimed at developing and evaluating improved catalysts for a slurry Fischer-Tropsch (FT) process for converting synthesis gas to high quality transportation fuels (gasoline and distillate). The improvements in catalyst performance were sought by studying effects of pretreatment conditions, promoters and binders/supports. A total of 20 different, iron based, catalysts were evaluated in 58 fixed bed reactor tests and 10 slurry reactor tests. The major accomplishments and conclusions are summarized below. The pretreatment conditions (temperature, duration and the nature of reducing gas) have significant effect on catalyst performance (activity, selectivity and stability) during Fischer-Tropsch synthesis. One of precipitated unsupported catalysts had hydrocarbon selectivity similar to Mobil`s I-B catalyst in high wax mode operation, and had not experienced any loss in activity during 460 hours of testing under variable process conditions in a slurry reactor. The effect of promoters (copper and potassium) on catalyst performance during FT synthesis has been studied in a systematic way. It was found that potassium promotion increases activities of the FT and water-gas-shift (WGS) reactions, the average molecular weight of hydrocarbon products, and suppresses the olefin hydrogenation and isomerization reactions. The addition of binders/supports (silica or alumina) to precipitated Fe/Cu/K catalysts, decreased their activity but improved their stability and hydrocarbon selectivity. The performance of catalysts of this type was very promising and additional studies are recommended to evaluate their potential for use in commercial slurry reactors.

  12. Electrochemical catalyst recovery method

    Science.gov (United States)

    Silva, Laura J.; Bray, Lane A.

    1995-01-01

    A method of recovering catalyst material from latent catalyst material solids includes: a) combining latent catalyst material solids with a liquid acid anolyte solution and a redox material which is soluble in the acid anolyte solution to form a mixture; b) electrochemically oxidizing the redox material within the mixture into a dissolved oxidant, the oxidant having a potential for oxidation which is effectively higher than that of the latent catalyst material; c) reacting the oxidant with the latent catalyst material to oxidize the latent catalyst material into at least one oxidized catalyst species which is soluble within the mixture and to reduce the oxidant back into dissolved redox material; and d) recovering catalyst material from the oxidized catalyst species of the mixture. The invention is expected to be particularly useful in recovering spent catalyst material from petroleum hydroprocessing reaction waste products having adhered sulfides, carbon, hydrocarbons, and undesired metals, and as well as in other industrial applications.

  13. Monolithically integrated interferometer for optical displacement measurement

    Science.gov (United States)

    Hofstetter, Daniel; Zappe, Hans P.

    1996-01-01

    We discuss the fabrication of a monolithically integrated optical displacement sensors using III-V semiconductor technology. The device is configured as a Michelson interferometer and consists of a distributed Bragg reflector laser, a photodetector and waveguides forming a directional coupler. Using this interferometer, displacements in the 100 nm range could be measured at distances of up to 45 cm. We present fabrication, device results and characterization of the completed interferometer, problems, limitations and future applications will also be discussed.

  14. An overview of monolithic zirconia in dentistry

    Directory of Open Access Journals (Sweden)

    Özlem Malkondu

    2016-07-01

    Full Text Available Zirconia restorations have been used successfully for years in dentistry owing to their biocompatibility and good mechanical properties. Because of their lack of translucency, zirconia cores are generally veneered with porcelain, which makes restorations weaker due to failure of the adhesion between the two materials. In recent years, all-ceramic zirconia restorations have been introduced in the dental sector with the intent to solve this problem. Besides the elimination of chipping, the reduced occlusal space requirement seems to be a clear advantage of monolithic zirconia restorations. However, scientific evidence is needed to recommend this relatively new application for clinical use. This mini-review discusses the current scientific literature on monolithic zirconia restorations. The results of in vitro studies suggested that monolithic zirconia may be the best choice for posterior fixed partial dentures in the presence of high occlusal loads and minimal occlusal restoration space. The results should be supported with much more in vitro and particularly in vivo studies to obtain a final conclusion.

  15. 浆态床合成二甲醚用CuZnAlSi催化剂的完全液相法制备及表征%Complete liquid phase preparation and characterization of CuZnAlSi catalysts for DME synthesis in slurry reactor

    Institute of Scientific and Technical Information of China (English)

    李志红; 黄伟; 樊金串; 左志军; 谢克昌

    2009-01-01

    采用完全液相法制备了不同SiO_2含量的二甲醚(DME)合成CuZnAlSi双功能催化剂,并在浆态床反应器中评价其催化反应活性,通过in-situ XPS、XRD、BET、NH_3-TPD等方法对其物理化学性能进行研究.结果表明,CuZnAl催化剂中加入SiO_2组分,能够促进活性组分Cu的分散,并通过与AlOOH的作用调变催化剂的孔结构和表面酸性,从而提高催化剂在DME合成反应中的活性.准原位 XPS表征结果显示,还原后的催化剂表面Cu0和ZnO共同构成DME合成反应中的甲醇合成活性中心.SiO_2的加入可能导致Cu、Zn和Al组分间的相互作用减弱,催化剂稳定性降低.%A series of CuZnAlSi bifunctional catalysts with different SiO_2 contents were prepared by a complete liquid phase method, and the catalysts were characterized by using in-situ XPS, XRD, BET and NH_3-TPD. The catalytic performance was evaluated in a slurry reactor. Based on these results, it was deduced that SiO_2 in the CuZnAlSi catalyst could interact with A1OOH resulting in the change of some physicochemical properties, such as the pore structure and surface acidity, thus the catalytic activity for DME synthesis has got improved. It was found from the in-situ XPS characterization that the surface active species for the methanol synthesis in the process of DME production is composed by the reduced Cu~0 species and ZnO. However, the stability of the catalyst decreased owing to the introduction of SiO_2, which may due to a lower interaction among the components of Cu, Zn and Al.

  16. Study on Olefins Yield from Methanol Conversion over Different Catalysts

    Institute of Scientific and Technical Information of China (English)

    Munib Shahda; Yan Dengchao; Wang Zhihe; Wen Huixin

    2006-01-01

    Conversion of Methanol to Olefins (MTO) under different reaction conditions was experimentally investigated over different catalysts, and comparison was made between the SAPO-34 and GOR-MLC catalysts. Optimization of reaction conditions has been explored. Conversion of methanol to olefins over these catalysts under different reaction temperatures was experimentally studied. In a fixed bed micro-reactor, the influence of temperature was found to be one of the major factors. For both catalysts the olefins yield was increased significantly when water was added to the methanol feed. A temperature range of 460-480 ℃ appeared to be the optimum range suitable for methanol conversion with appropriate catalyst activity and C2-C3 olefins yield. Some other hydrocarbons appeared during the MTO reaction in the presence of the SAPO-34 catalyst, while a lot of dimethylether was formed when the GOR-MLC catalyst was used. In the course of the MTO reaction, the GOR-MLC catalyst was found to have a faster catalyst deactivation rate compared to the SAPO-34 catalyst.

  17. Synthesis of light hydrocarbons over Fe/AC catalysts

    Institute of Scientific and Technical Information of China (English)

    Zhao Jianjun; Zong Zhimin; Wang Taotao; Liu Tong; Wei Xianyong

    2012-01-01

    A series of Fe/AC catalysts for catalytic hydrogenation of CO to light hydrocarbons (LHCs) were prepared by decomposing Fe(CO)5 in an autoclave.The catalysts activities were tested in a high-pressure micro reactor.The results show that both CO conversion and LHCs selectivity were significantly affected by the amount of Fe loaded onto the catalysts.The optimum Fe content was determined to be 10% by weight of the catalyst.Over the corresponding catalyst (i.e.,10% Fe/C catalyst),the conversion of CO and the selectivity of LHC5 were 94.8% and 59.2%,respectively,at 360 ℃.Based on various catalyst characterization techniques,such as XRD,BET and SEM,the catalysts surface areas and pore volume decreased and the smaller particles agglomerated at the edges and corners in the outer region of the support with the increasing Fe content.The agglomerated particles increased greatly when the iron content of the catalyst was higher than 10%.The decrease of catalyst activity can be due to the agglomerated particles.

  18. Preparation of imprinted monolithic column under molecular crowding conditions

    Institute of Scientific and Technical Information of China (English)

    Xiao Xia Li; Xin Liu; Li Hong Bai; Hong Quan Duan; Yan Ping Huang; Zhao Sheng Liu

    2011-01-01

    Molecular crowding is a new concept to obtain molecularly imprinted polymers (MIPs) with greater capacity and selectivity. In this work, molecular crowding agent was firstly applied to the preparation of MIPs monolithic column. A new polymerization system based on molecular crowding surrounding was developed to prepare enrofloxacin-imprinted monolith, which was composed of polystyrene and tetrahydrofuran. The result showed that the monolithic MIPs under molecular crowding conditions presented good molecular recognition for enrofloxacin with an imprinting factor of 3.03.

  19. Modelling and simulation of a membrane reactor for the oxidation of methane with simultaneous steam reforming using O2-selective perowskite hollow fibres

    OpenAIRE

    Hamel, C.; Tota, A.; Wang, H.; Tablet, C.; Caro, J; Tsotsas, E.

    2006-01-01

    The generation of synthesis gas from methane is currently performed by conventional steam reforming or by partial oxidation (POX) in fixed-bed reactors using nickel or noble metal based catalysts. These catalysts offer the possibility to reach high yields at temperatures around 900°C [1]. In the last years several new reactor concepts were suggested to intensify the heat exchange, e.g. auto thermal reformers, catalytic coated wall reactors, fluidised bed or membrane reactors [2]. Improved POX...

  20. Propan-1-ol Oxidation Reaction on Au/TiO2 Catalysts

    African Journals Online (AJOL)

    MBI

    2014-11-27

    Nov 27, 2014 ... Department of pure and applied Chemistry, Bayero University, Kano P.M.B 3011, Kano State, Nigeria ... using Pulse Flow reactor, TPFRP, TPD, and XRD,. ... complete oxidation reaction of propan-1-ol on the catalysts.

  1. Monolithic Lumped Element Integrated Circuit (M2LEIC) Transistors.

    Science.gov (United States)

    INTEGRATED CIRCUITS, *MONOLITHIC STRUCTURES(ELECTRONICS), *TRANSISTORS, CHIPS(ELECTRONICS), FABRICATION, EPITAXIAL GROWTH, ULTRAHIGH FREQUENCY, POLYSILICONS, PHOTOLITHOGRAPHY, RADIOFREQUENCY POWER, IMPEDANCE MATCHING .

  2. Oxidative coupling of methane using inorganic membrane reactor

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Y.H.; Moser, W.R.; Dixon, A.G. [Worcester Polytechnic Institute, MA (United States)] [and others

    1995-12-31

    The goal of this research is to improve the oxidative coupling of methane in a catalytic inorganic membrane reactor. A specific target is to achieve conversion of methane to C{sub 2} hydrocarbons at very high selectivity and relatively higher yields than in fixed bed reactors by controlling the oxygen supply through the membrane. A membrane reactor has the advantage of precisely controlling the rate of delivery of oxygen to the catalyst. This facility permits balancing the rate of oxidation and reduction of the catalyst. In addition, membrane reactors minimize the concentration of gas phase oxygen thus reducing non selective gas phase reactions, which are believed to be a main route for formation of CO{sub x} products. Such gas phase reactions are a cause for decreased selectivity in oxidative coupling of methane in conventional flow reactors. Membrane reactors could also produce higher product yields by providing better distribution of the reactant gases over the catalyst than the conventional plug flow reactors. Modeling work which aimed at predicting the observed experimental trends in porous membrane reactors was also undertaken in this research program.

  3. Improved Fischer-Tropsch Slurry Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Andrew Lucero

    2009-03-20

    The conversion of synthesis gas to hydrocarbons or alcohols involves highly exothermic reactions. Temperature control is a critical issue in these reactors for a number of reasons. Runaway reactions can be a serious safety issue, even raising the possibility of an explosion. Catalyst deactivation rates tend to increase with temperature, particularly of there are hot spots in the reactor. For alcohol synthesis, temperature control is essential because it has a large effect on the selectivity of the catalysts toward desired products. For example, for molybdenum disulfide catalysts unwanted side products such as methane, ethane, and propane are produced in much greater quantities if the temperature increases outside an ideal range. Slurry reactors are widely regarded as an efficient design for these reactions. In a slurry reactor a solid catalyst is suspended in an inert hydrocarbon liquid, synthesis gas is sparged into the bottom of the reactor, un-reacted synthesis gas and light boiling range products are removed as a gas stream, and heavy boiling range products are removed as a liquid stream. This configuration has several positive effects for synthesis gas reactions including: essentially isothermal operation, small catalyst particles to reduce heat and mass transfer effects, capability to remove heat rapidly through liquid vaporization, and improved flexibility on catalyst design through physical mixtures in addition to use of compositions that cannot be pelletized. Disadvantages include additional mass transfer resistance, potential for significant back-mixing on both the liquid and gas phases, and bubble coalescence. In 2001 a multiyear project was proposed to develop improved FT slurry reactors. The planned focus of the work was to improve the reactors by improving mass transfer while considering heat transfer issues. During the first year of the project the work was started and several concepts were developed to prepare for bench-scale testing. Power

  4. Characterization of production of free gluconic acid by Gluconobacter suboxydans adsorbed on ceramic honeycomb monolith.

    Science.gov (United States)

    Shiraishi, F; Kawakami, K; Kono, S; Tamura, A; Tsuruta, S; Kusunoki, K

    1989-05-01

    Gluconobacter suboxydans IFO 3290 was immobilized by adsorption on ceramic honeycomb monolith and continuous production of free gluconic acid from glucose was performed in an aerated reactor. The effects of reactor residence time, aeration rate, and glucose concentration were investigated on the gluconic acid yield. Observation of SEM photographs revealed that the cells were adsorbed with a high density not only on the outer surface of the support but also on the inner surface of large pores. From measurement of the number of the adsorbed cells, it was elucidated that the biofilm comprised a monolayer or bilayer of the cells. Maximum specific rate of growth was estimated for the free and adsorbed cells, and the adsorbed cells were found to grow at a fast rate compared with the free cells. In the continuous fermentation performed for one month at the glucose concentration of 100 kg/m(3), reactor residence time of 3.5 h and aeration rate of 900 cm(3)/min, the activity of the adsorbed cells was appreciably stable. The high productivity of 26.3 kg/(m(3)-reactor . h) was attained with the gluconic acid yield of 84.6% and glucose conversion of 94%.

  5. An easily regenerable enzyme reactor prepared from polymerized high internal phase emulsions.

    Science.gov (United States)

    Ruan, Guihua; Wu, Zhenwei; Huang, Yipeng; Wei, Meiping; Su, Rihui; Du, Fuyou

    2016-04-22

    A large-scale high-efficient enzyme reactor based on polymerized high internal phase emulsion monolith (polyHIPE) was prepared. First, a porous cross-linked polyHIPE monolith was prepared by in-situ thermal polymerization of a high internal phase emulsion containing styrene, divinylbenzene and polyglutaraldehyde. The enzyme of TPCK-Trypsin was then immobilized on the monolithic polyHIPE. The performance of the resultant enzyme reactor was assessed according to the conversion ability of Nα-benzoyl-l-arginine ethyl ester to Nα-benzoyl-l-arginine, and the protein digestibility of bovine serum albumin (BSA) and cytochrome (Cyt-C). The results showed that the prepared enzyme reactor exhibited high enzyme immobilization efficiency and fast and easy-control protein digestibility. BSA and Cyt-C could be digested in 10 min with sequence coverage of 59% and 78%, respectively. The peptides and residual protein could be easily rinsed out from reactor and the reactor could be regenerated easily with 4 M HCl without any structure destruction. Properties of multiple interconnected chambers with good permeability, fast digestion facility and easily reproducibility indicated that the polyHIPE enzyme reactor was a good selector potentially applied in proteomics and catalysis areas.

  6. One-pot synthesis of network supported catalyst using supramolecular gel as template

    Institute of Scientific and Technical Information of China (English)

    Yong Liang; Li Ming Tang; Yu Xia; Kai Chen; Bo Tian Li; Xin Jin

    2010-01-01

    A simple and general strategy is described for preparing network supported catalyst through a one-pot synthetic procedure using supramolecular gel as template. This procedure directly attaches iigand to support during fabricating the support. Using this strategy, supported CuBr/di-(2-picolyl)amine catalyst with U-shaped fibrillar network was prepared and used in atom transfer radical polymerization of methyl methacrylate. XPS and SEM characterization of the catalyst revealed homogeneous distribution of ligand, sufficient reactive sites, adequate mechanical strength and macroporosity. The polymerization results demonstrated high activity and reusability of such catalyst. This strategy might be extended to other supported catalysts used in column reactors.

  7. Crosslinked, cryostructured Lactobacillus reuteri monoliths for production of 3-hydroxypropionaldehyde, 3-hydroxypropionic acid and 1,3-propanediol from glycerol.

    Science.gov (United States)

    Zaushitsyna, Oksana; Dishisha, Tarek; Hatti-Kaul, Rajni; Mattiasson, Bo

    2017-01-10

    Crosslinked, cryostructured monoliths prepared from Lactobacillus reuteri cells were evaluated as potential immobilized whole-cell biocatalyst for conversion of glycerol, to potentially important chemicals for the biobased industry, i.e. 3-hydroxypropionaldehyde (3HPA), 3-hydroxypropionic acid (3HP) and 1,3-propanediol (1,3PDO). Glutaraldehyde, oxidized dextran and activated polyethyleneimine/modified polyvinyl alcohol (PEI/PVA) were evaluated as crosslinkers; the latter gave highly stable preparations with maintained viability and biocatalytic activity. Scanning electron microscopy of the PEI/PVA monoliths showed high density of crosslinked cells with wide channels allowing liquid flow through. Flux analysis of the propanediol-utilization pathway, incorporating glycerol/diol dehydratase, propionaldehyde dehydrogenase, 1,3PDO oxidoreductase, phosphotransacylase, and propionate kinase, for conversion of glycerol to the three chemicals showed that the maximum specific reaction rates were -562.6, 281.4, 62.4 and 50.5mg/gCDWh for glycerol consumption, and 3HPA (extracellular), 3HP and 1,3PDO production, respectively. Under optimal conditions using monolith operated as continuous plug flow reactor, 19.7g/L 3HPA was produced as complex with carbohydrazide at a rate of 9.1g/Lh and a yield of 77mol%. Using fed-batch operation, 1,3PDO and 3HP were co-produced in equimolar amounts with a yield of 91mol%. The monoliths embedded in plastic carriers showed high mechanical stability under different modes in a miniaturized plug flow reactor.

  8. SCALEUP OF ALUMINUM PHOSPHATE CATALYST FOR PILOT PLANT LPDMEtm RUN

    Energy Technology Data Exchange (ETDEWEB)

    Andrew W. Wang

    2002-01-01

    The Liquid Phase Dimethyl Ether (LPDME{trademark}) process converts synthesis gas to dimethyl ether in a single slurry bubble column reactor. A mixed slurry of methanol synthesis catalyst and methanol dehydration catalyst in a neutral mineral oil simultaneously synthesizes methanol from syngas and converts some of it to dimethyl ether and water. The reaction scheme is shown below: 2H{sub 2} + CO = CH{sub 3}OH; 2CH{sub 3}OH = CH{sub 3}OCH{sub 3} + H{sub 2}O; H{sub 2}O + CO = CO{sub 2} + H{sub 2}. Most of the water produced in this reaction is converted to hydrogen by reduction with carbon monoxide (water gas shift reaction). This synergy permits higher per pass conversion than methanol synthesis alone. The enhancement in conversion occurs because dehydration of the methanol circumvents the equilibrium constraint of the syngas-to-methanol step. The slurry bubble column reactor provides the necessary heat transfer capacity to handle the greater heat duty associated with high conversion. In order to improve the stability of the catalyst system, non-stoichiometric aluminum phosphate was proposed as the dehydration catalyst for the LPDME{trademark} process. This aluminum phosphate material is a proprietary catalyst. This catalyst system of a standard methanol catalyst and the aluminum phosphate provided stable process performance that met the program targets under our standard test process conditions in the laboratory. These targets are (1) an initial methanol equivalent productivity of 28 gmol/kg/hr, (2) a CO{sub 2}-free, carbon selectivity of 80% to dimethyl ether and (3) stability of both catalysts equivalent to that of the methanol catalyst in the absence of the aluminum phosphate. A pilot plant trial of the LPDME{trademark} process using the aluminum phosphate catalyst was originally planned for March 1998 at the DOE-owned, Air Products (APCI)-operated facility at LaPorte, Texas. Because the aluminum phosphate catalyst is not commercially available, we initiated a

  9. SCALEUP OF ALUMINUM PHOSPHATE CATALYST FOR PILOT PLANT LPDMEtm RUN

    Energy Technology Data Exchange (ETDEWEB)

    Andrew W. Wang

    2002-05-15

    The Liquid Phase Dimethyl Ether (LPDME{trademark}) process converts synthesis gas to dimethyl ether in a single slurry bubble column reactor. A mixed slurry of methanol synthesis catalyst and methanol dehydration catalyst in a neutral mineral oil simultaneously synthesizes methanol from syngas and converts some of it to dimethyl ether and water. The reaction scheme is: 2H{sub 2} + CO = CH{sub 3}OH 2CH{sub 3}OH = CH{sub 3}OCH{sub 3} + H{sub 2}O H{sub 2}O + CO = CO{sub 2} + H{sub 2}. Most of the water produced in this reaction is converted to hydrogen by reduction with carbon monoxide (water gas shift reaction). This synergy permits higher per pass conversion than methanol synthesis alone. The enhancement in conversion occurs because dehydration of the methanol circumvents the equilibrium constraint of the syngas-to-methanol step. The slurry bubble column reactor provides the necessary heat transfer capacity to handle the greater heat duty associated with high conversion. In order to improve the stability of the catalyst system, non-stoichiometric aluminum phosphate was proposed as the dehydration catalyst for the LPDME{trademark} process. This aluminum phosphate material is a proprietary catalyst. This catalyst system of a standard methanol catalyst and the aluminum phosphate provided stable process performance that met the program targets under our standard test process conditions in the laboratory. These targets are (1) an initial methanol equivalent productivity of 28 gmol/kg/hr, (2) a CO{sub 2}-free, carbon selectivity of 80% to dimethyl ether and (3) stability of both catalysts equivalent to that of the methanol catalyst in the absence of the aluminum phosphate. A pilot plant trial of the LPDME{trademark} process using the aluminum phosphate catalyst was originally planned for March 1998 at the DOE-owned, Air Products (APCI)-operated facility at LaPorte, Texas. Because the aluminum phosphate catalyst is not commercially available, we initiated a scaleup project

  10. A Monolithically Integrated Gallium Nitride Nanowire/Silicon Solar Cell Photocathode for Selective Carbon Dioxide Reduction to Methane.

    Science.gov (United States)

    Wang, Yichen; Fan, Shizhao; AlOtaibi, Bandar; Wang, Yongjie; Li, Lu; Mi, Zetian

    2016-06-20

    A gallium nitride nanowire/silicon solar cell photocathode for the photoreduction of carbon dioxide (CO2 ) is demonstrated. Such a monolithically integrated nanowire/solar cell photocathode offers several unique advantages, including the absorption of a large part of the solar spectrum and highly efficient carrier extraction. With the incorporation of copper as the co-catalyst, the devices exhibit a Faradaic efficiency of about 19 % for the 8e(-) photoreduction to CH4 at -1.4 V vs Ag/AgCl, a value that is more than thirty times higher than that for the 2e(-) reduced CO (ca. 0.6 %).

  11. Bioconversion reactor

    Science.gov (United States)

    McCarty, Perry L.; Bachmann, Andre

    1992-01-01

    A bioconversion reactor for the anaerobic fermentation of organic material. The bioconversion reactor comprises a shell enclosing a predetermined volume, an inlet port through which a liquid stream containing organic materials enters the shell, and an outlet port through which the stream exits the shell. A series of vertical and spaced-apart baffles are positioned within the shell to force the stream to flow under and over them as it passes from the inlet to the outlet port. The baffles present a barrier to the microorganisms within the shell causing them to rise and fall within the reactor but to move horizontally at a very slow rate. Treatment detention times of one day or less are possible.

  12. Foundation Flash Catalyst

    CERN Document Server

    Goralski, Greg

    2010-01-01

    This book offers an introduction to Flash Catalyst for designers with intermediate to advanced skills. It discusses where Catalyst sits within the production process and how it communicates with other programs. It covers all of the features of the Flash Catalyst workspace, teaching you how to create designs from scratch, how to build application designs and add functionality, and how to master the Catalyst/Flex workflow. * Introduces Flash Catalyst * Focuses on production process * Covers the interrelation between Flash Catalyst and Photoshop/Illustrator/Flex/Flash What you'll learn Starting f

  13. Non-Conventional Plasma Assisted Catalysts for Diesel Exhaust Treatment: A Case Study

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    This paper reports the application of pulse discharges along with catalysts in treating the exhaust gas at higher temperatures. In the present work a plasma reactor, filled with catalysts, called as plasma catalytic reactor, is studied for removal of oxides of nitrogen, total hydrocarbons and carbon monoxide. The experiments are conducted on an actual diesel engine exhaust at no-load and at different temperatures starting from room temperature to 300℃. The removal efficiencies of these pollutants are studied. The experiments are carried out with both conventional and non-conventional catalysts. The idea is to explore the pollutant removal efficiency characteristics by non-conventional catalysts. The efficiency results are compared with that of conventional catalysts. The experiments are carried out at a constant pulse repetition rate of 120 pps. Both pellet and honeycomb type catalysts are used in the study.

  14. Toluene Oxidation by Non-Thermal Plasma Combined with Palladium Catalysts

    Directory of Open Access Journals (Sweden)

    Monica eMagureanu

    2013-06-01

    Full Text Available The oxidation of toluene in air was investigated using a dielectric barrier discharge (DBD combined with a Pd/Al2O3 catalyst. When using only plasma, rather low selectivity towards CO2 was obtained: 32-35%. By filling the DBD reactor with Pd/Al2O3 catalyst the CO2 selectivity was significantly enhanced (80-90%, however, a large amount of toluene was desorbed from the catalyst when the discharge was operated. By filling a quarter of the discharge gap with catalyst and placing the rest of the catalyst downstream of the plasma reactor, an important increase of CO2 selectivity (~75% and a 15% increase in toluene conversion were achieved as compared to the results with plasma alone. The catalyst exhibited a very good stability in this reaction.

  15. Microstructural Characteristics of HIP-bonded Monolithic Nuclear Fuels with a Diffusion Barrier

    Energy Technology Data Exchange (ETDEWEB)

    Jan-Fong Jue; Dennis D. Keiser, Jr.; Cynthia R. Breckenridge; Glenn A. Moore; Mitchell K. Meyer

    2014-05-01

    Due to the limitation of maximum uranium load achievable by dispersion fuel type, the Global Threat Reduction Initiative (GTRI) is developing an advanced monolithic fuel to convert US high performance research reactors to low-enriched uranium. Hot-isostatic-press bonding was the single process down-selected to bond monolithic U-Mo fuel meat to aluminum alloy cladding. A diffusion barrier was applied to the U–Mo fuel meat by roll-bonding process to prevent extensive interaction between fuel meat and aluminum-alloy cladding. Microstructural characterization was performed on fresh fuel plates fabricated at Idaho National Laboratory. Interfaces between fuel meat, cladding, and diffusion barrier, as well as U–10Mo fuel meat and Al–6061 cladding were characterized by scanning electron microscopy. Preliminary results indicate that the interfaces contain many different phases while decomposition, second phases, and chemical banding were also observed in the fuel meat. The important attributes of the HIP-bonded monolithic fuel are • A typical Zr diffusion barrier of thickness 25 µm • Transverse cross section that exhibits relatively equiaxed grains with an average grain diameter of 10 µm • Chemical banding, in some areas more than 100 µm in length, that is very pronounced in longitudinal (i.e., rolling) direction with Mo concentration varying from 7–13 wt% • Decomposed areas containing plate-shaped low-Mo phase • A typical Zr/cladding interaction layer of thickness 1-2 µm • A visible UZr2 bearing layer of thickness 1-2 µm • Mo-rich precipitates (mainly Mo2Zr, forming a layer in some areas) followed by a Mo-depleted sub-layer between the visible UZr2-bearing layer and the U–Mo matrix • No excessive interaction between cladding and the uncoated fuel edge • Cladding-to-cladding bonding that exhibits no cracks or porosity with second phases high in Mg, Si, and O decorating the bond line. • Some of these attributes might be critical to the

  16. Microstructural characteristics of HIP-bonded monolithic nuclear fuels with a diffusion barrier

    Energy Technology Data Exchange (ETDEWEB)

    Jue, Jan-Fong, E-mail: dennis.keiser@inl.gov; Keiser, Dennis D.; Breckenridge, Cynthia R.; Moore, Glenn A.; Meyer, Mitchell K.

    2014-05-01

    Due to the limitation of maximum uranium load achievable by dispersion fuel type, the Global Threat Reduction Initiative is developing an advanced monolithic fuel to convert US high-performance research reactors to low-enriched uranium. Hot-isostatic-press (HIP) bonding was the single process down-selected to bond monolithic U–Mo fuel meat to aluminum alloy cladding. A diffusion barrier was applied to the U–Mo fuel meat by roll-bonding process to prevent extensive interaction between fuel meat and aluminum-alloy cladding. Microstructural characterization was performed on fresh fuel plates fabricated at Idaho National Laboratory. Interfaces between the fuel meat, the cladding, and the diffusion barrier, as well as between the U–10Mo fuel meat and the Al-6061 cladding, were characterized by scanning electron microscopy. Preliminary results indicate that the interfaces contain many different phases while decomposition, second phases, and chemical banding were also observed in the fuel meat. The important attributes of the HIP-bonded monolithic fuel are: • A typical Zr diffusion barrier with a thickness of 25 μm. • A transverse cross section that exhibits relatively equiaxed grains with an average grain diameter of 10 μm. • Chemical banding, in some areas more than 100 μm in length, that is very pronounced in longitudinal (i.e., rolling) direction with Mo concentration varying from 7–13 wt.%. • Decomposed areas containing plate-shaped low-Mo phase. • A typical Zr/cladding interaction layer with a thickness of 1–2 μm. • A visible UZr{sub 2} bearing layer with a thickness of 1–2 μm. • Mo-rich precipitates (mainly Mo{sub 2}Zr, forming a layer in some areas) followed by a Mo-depleted sub-layer between the visible UZr{sub 2}-bearing layer and the U–Mo matrix. • No excessive interaction between cladding and the uncoated fuel edge. • Cladding-to-cladding bonding that exhibits no cracks or porosity with second phases high in Mg, Si, and O

  17. Microstructural characteristics of HIP-bonded monolithic nuclear fuels with a diffusion barrier

    Science.gov (United States)

    Jue, Jan-Fong; Keiser, Dennis D.; Breckenridge, Cynthia R.; Moore, Glenn A.; Meyer, Mitchell K.

    2014-05-01

    Due to the limitation of maximum uranium load achievable by dispersion fuel type, the Global Threat Reduction Initiative is developing an advanced monolithic fuel to convert US high-performance research reactors to low-enriched uranium. Hot-isostatic-press (HIP) bonding was the single process down-selected to bond monolithic U-Mo fuel meat to aluminum alloy cladding. A diffusion barrier was applied to the U-Mo fuel meat by roll-bonding process to prevent extensive interaction between fuel meat and aluminum-alloy cladding. Microstructural characterization was performed on fresh fuel plates fabricated at Idaho National Laboratory. Interfaces between the fuel meat, the cladding, and the diffusion barrier, as well as between the U-10Mo fuel meat and the Al-6061 cladding, were characterized by scanning electron microscopy. Preliminary results indicate that the interfaces contain many different phases while decomposition, second phases, and chemical banding were also observed in the fuel meat. The important attributes of the HIP-bonded monolithic fuel are: diffusion barrier with a thickness of 25 μm. A transverse cross section that exhibits relatively equiaxed grains with an average grain diameter of 10 μm. Chemical banding, in some areas more than 100 μm in length, that is very pronounced in longitudinal (i.e., rolling) direction with Mo concentration varying from 7-13 wt.%. Decomposed areas containing plate-shaped low-Mo phase. A typical Zr/cladding interaction layer with a thickness of 1-2 μm. A visible UZr2 bearing layer with a thickness of 1-2 μm. Mo-rich precipitates (mainly Mo2Zr, forming a layer in some areas) followed by a Mo-depleted sub-layer between the visible UZr2-bearing layer and the U-Mo matrix. No excessive interaction between cladding and the uncoated fuel edge. Cladding-to-cladding bonding that exhibits no cracks or porosity with second phases high in Mg, Si, and O decorating the bond line. Some of these attributes might be critical to the

  18. Electrochemical Membrane Reactors for Sustainable Chlorine Recycling

    Directory of Open Access Journals (Sweden)

    Ulrich Kunz

    2012-07-01

    Full Text Available Polymer electrolyte membranes have found broad application in a number of processes, being fuel cells, due to energy concerns, the main focus of the scientific community worldwide. Relatively little attention has been paid to the use of these materials in electrochemical production and separation processes. In this review, we put emphasis upon the application of Nafion membranes in electrochemical membrane reactors for chlorine recycling. The performance of such electrochemical reactors can be influenced by a number of factors including the properties of the membrane, which play an important role in reactor optimization. This review discusses the role of Nafion as a membrane, as well as its importance in the catalyst layer for the formation of the so-called three-phase boundary. The influence of an equilibrated medium on the Nafion proton conductivity and Cl crossover, as well as the influence of the catalyst ink dispersion medium on the Nafion/catalyst self-assembly and its importance for the formation of an ionic conducting network in the catalyst layer are summarized.

  19. Electrochemical Membrane Reactors for Sustainable Chlorine Recycling

    Science.gov (United States)

    Vidakovic-Koch, Tanja; Martinez, Isai Gonzalez; Kuwertz, Rafael; Kunz, Ulrich; Turek, Thomas; Sundmacher, Kai

    2012-01-01

    Polymer electrolyte membranes have found broad application in a number of processes, being fuel cells, due to energy concerns, the main focus of the scientific community worldwide. Relatively little attention has been paid to the use of these materials in electrochemical production and separation processes. In this review, we put emphasis upon the application of Nafion membranes in electrochemical membrane reactors for chlorine recycling. The performance of such electrochemical reactors can be influenced by a number of factors including the properties of the membrane, which play an important role in reactor optimization. This review discusses the role of Nafion as a membrane, as well as its importance in the catalyst layer for the formation of the so-called three-phase boundary. The influence of an equilibrated medium on the Nafion proton conductivity and Cl− crossover, as well as the influence of the catalyst ink dispersion medium on the Nafion/catalyst self-assembly and its importance for the formation of an ionic conducting network in the catalyst layer are summarized. PMID:24958294

  20. Catalytic hydrotreatment of Alcell lignin fractions using a Ru/C catalyst

    NARCIS (Netherlands)

    Kloekhorst, Arjan; Heeres, Hero Jan

    2016-01-01

    We here report the catalytic hydrotreatment of three different Alcell lignin fractions using a Ru/C catalyst in a batch reactor set-up (400 °C, 4 h, 100 bar H2 intake, 5 wt% catalyst on lignin). The fractions, obtained by a solvent fractionation scheme from Alcell lignin, differ in composition and m

  1. Glycerol valorization: dehydration to acrolein over silica-supported niobia catalysts

    NARCIS (Netherlands)

    Shiju, N.R.; Brown, D.R.; Wilson, K.; Rothenberg, G.

    2010-01-01

    The catalytic dehydration of glycerol to acrolein is investigated over silica-supported niobia catalysts in a continuous fixed-bed gas-phase reactor. Various supported niobia catalysts are prepared and characterized using surface analysis and spectroscopic methods (XRD, UV-Vis, XPS, N2 adsorption),

  2. Commercial Application of the ICR Series Lube Isodewaxing Catalysts

    Institute of Scientific and Technical Information of China (English)

    Wang Sijue

    2008-01-01

    This article illustrates the application of the ICR series lube oil isodewaxing catalysts in commercial scale and proposes the strategy on long cycle operation and optimization of catalysts. The results of commercial application of the catalyst have revealed that the catalyst after pretreatment including drying, sulfidation and reduction can process VGO into base oils meeting the HVI Ⅱ and HVI Ⅱ+ standards, and can manufacture base oils meeting the HVI Ⅲ standard after incorporating the filtrate oil or gatch from acetone-benzene solvent dewaxing unit. The nitrogen content of the feed oil to the IDW reactor should be controlled at 1.0-1.5 ppm, while the CO and CO2 contents in fresh hydrogen is strictly controlled to avoid poisoning of the IDW-HDF catalysts.

  3. Hydrogenation of Tetralin over Supported Ni and Ir Catalysts

    Directory of Open Access Journals (Sweden)

    Dipali P. Upare

    2013-01-01

    Full Text Available Selective hydrogenation and ring opening (SRO of tetrahydronaphthalene (tetralin was studied over nickel and iridium supported catalysts in the context of the removal of polynuclear aromatics from diesel fuel. The tetralin hydrogenation was carried out in a fixed-bed reactor at 270°C, using H2 pressure of 30 bars, WHSV of 2.3 h−1, and H2/feed molar ratio of 40; the resultant products were analyzed by GC and GC-MS. The Ir/SiO2 catalyst gave 85% of tetralin conversion and 75.1% of decalin products selectivity whereas Ni/SiO2 catalyst showed an unprecedented high catalytic performance with 88.3% of tetralin conversion and 93% of decalin products selectivity. The catalysts were characterized by using different characterization techniques such as XRD, TPR, and HR-TEM to know the physicochemical properties as well as active sites in the catalysts.

  4. ATTRITION RESISTANT IRON-BASED FISCHER-TROPSCH CATALYSTS

    Energy Technology Data Exchange (ETDEWEB)

    K. Jothimurugesan; James G. Goodwin, Jr.; Santosh K. Gangwal

    1999-10-01

    Fischer-Tropsch (FT) synthesis to convert syngas (CO + H{sub 2}) derived from natural gas or coal to liquid fuels and wax is a well-established technology. For low H{sub 2} to CO ratio syngas produced from CO{sub 2} reforming of natural gas or from gasification of coal, the use of Fe catalysts is attractive because of their high water gas shift activity in addition to their high FT activity. Fe catalysts are also attractive due to their low cost and low methane selectivity. Because of the highly exothermic nature of the FT reaction, there has been a recent move away from fixed-bed reactors toward the development of slurry bubble column reactors (SBCRs) that employ 30 to 90 {micro}m catalyst particles suspended in a waxy liquid for efficient heat removal. However, the use of FeFT catalysts in an SBCR has been problematic due to severe catalyst attrition resulting in fines that plug the filter employed to separate the catalyst from the waxy product. Fe catalysts can undergo attrition in SBCRs not only due to vigorous movement and collisions but also due to phase changes that occur during activation and reaction.

  5. Technology development for iron Fischer-Tropsch catalysts

    Energy Technology Data Exchange (ETDEWEB)

    O`Brien, R.J.; Raje, A.; Keogh, R.A. [and others

    1995-12-31

    The objective of this research project is to develop the technology for the production of physically robust iron-based Fischer-Tropsch catalysts that have suitable activity, selectivity and stability to be used in the slurry phase synthesis reactor development. The catalysts that are developed shall be suitable for testing in the Advanced Fuels Development Facility at LaPorte, Texas, to produce either low-or high-alpha product distributions. Previous work by the offeror has produced a catalyst formulation that is 1.5 times as active as the {open_quotes}standard-catalyst{close_quotes} developed by German workers for slurry phase synthesis. In parallel, work will be conducted to design a high-alpha iron catalyst this is suitable for slurry phase synthesis. Studies will be conducted to define the chemical phases present at various stages of the pretreatment and synthesis stages and to define the course of these changes. The oxidation/reduction cycles that are anticipated to occur in large, commercial reactors will be studied at the laboratory scale. Catalyst performance will be determined for catalysts synthesized in this program for activity, selectivity and aging characteristics.

  6. Attrition Resistant Fischer-Tropsch Catalysts Based on FCC Supports

    Energy Technology Data Exchange (ETDEWEB)

    Adeyiga, Adeyinka

    2010-02-05

    Commercial spent fluid catalytic cracking (FCC) catalysts provided by Engelhard and Albemarle were used as supports for Fe-based catalysts with the goal of improving the attrition resistance of typical F-T catalysts. Catalysts with the Ruhrchemie composition (100 Fe/5 Cu/4.2 K/25 spent FCC on mass basis) were prepared by wet impregnation. XRD and XANES analysis showed the presence of Fe{sub 2}O{sub 3} in calcined catalysts. FeC{sub x} and Fe{sub 3}O{sub 4} were present in the activated catalysts. The metal composition of the catalysts was analyzed by ICP-MS. F-T activity of the catalysts activated in situ in CO at the same conditions as used prior to the attrition tests was measured using a fixed bed reactor at T = 573 K, P = 1.38 MPa and H{sub 2}:CO ratio of 0.67. Cu and K promoted Fe supported over Engelhard provided spent FCC catalyst shows relatively good attrition resistance (8.2 wt% fines lost), high CO conversion (81%) and C{sub 5}+ hydrocarbons selectivity (18.3%).

  7. Mixed phase Pt-Ru catalyst for direct methanol fuel cell anode by flame aerosol synthesis

    DEFF Research Database (Denmark)

    Chakraborty, Debasish; Bischoff, H.; Chorkendorff, Ib

    2005-01-01

    A spray-flame aerosol catalyzation technique was studied for producing Pt-Ru anode electrodes for the direct methanol fuel cell. Catalysts were produced as aerosol nanoparticles in a spray-flame reactor and deposited directly as a thin layer on the gas diffusion layer. The as-prepared catalyst......Ru1/Vulcan carbon. The kinetics of methanol oxidation on the mixed phase catalyst was also explored by electrochemical impedance spectroscopy. (c) 2005 The Electrochemical Society....

  8. Preliminary Study on Reducing Olefin Content of FCC Gasoline over Cracking Catalyst

    Institute of Scientific and Technical Information of China (English)

    梁咏梅; 杨海峰; 刘耀芳; 徐春明

    2003-01-01

    Using fixed bed micro-reactor and cracking catalyst, re-cracking of fluid catalytic cracking (FCC) gasoline at lower temperature than conventional cracking condition has been studied. The results reveal that at lower temperature from 350℃-450℃ and catalyst to feed ratio of 3, the olefin content is reduced from 49% to 27%(by mass) over the catalyst whose micro-reacting activation index is 53, and the octane number is kept on high level.

  9. Preparation of Mesoporous Silica-Supported Palladium Catalysts for Biofuel Upgrade

    OpenAIRE

    Ling Fei; Harvind Kumar Reddy; Joshua Hill; Qianglu Lin; Bin Yuan; Yun Xu; Peter Dailey; Shuguang Deng; Hongmei Luo

    2012-01-01

    We report the preparation of two hydrocracking catalysts Pd/CoMoO4/silica and Pd/CNTs/CoMoO4/silica (CNTs, carbon nanotubes). The structure, morphologies, composition, and thermal stability of catalysts were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman spectroscopy, transmission electron microscopy (TEM), energy-dispersive X-ray (EDX), and thermogravimetric analysis (TGA). The catalyst activity was measured in a Parr reactor with camelina fatty acid methyl est...

  10. Role of dehydration catalyst acid properties on one-step DME synthesis over physical mixtures

    OpenAIRE

    Fraga, Marco André; Appel, Lúcia Gorenstin; Farias, Andréa Maria Duarte de; Ramos,F.S.; Borges, Luiz Eduardo Pizarro; Monteiro, José L. F.; Souza-Aguiar, E. F.

    2005-01-01

    The direct synthesis of dimethyl ether (DME) was studied in a continuous high-pressure unit composed basically of a Berty reactor and online gas chromatograph. A commercial methanol synthesis catalyst and some solid-acid catalysts (alumina. HZSM-S. tungsten-zirconia and sulfated-zirconia) were used as physical mixtures. The dehydration catalysts were characterised by pyridine adsorption followed by IR spectroscopy and tested in the methanol dehydration reaction itself. All samples were active...

  11. Energy Absorption of Monolithic and Fibre Reinforced Aluminium Cylinders

    NARCIS (Netherlands)

    De Kanter, J.L.C.G.

    2006-01-01

    Summary accompanying the thesis: Energy Absorption of Monolithic and Fibre Reinforced Aluminium Cylinders by Jens de Kanter This thesis presents the investigation of the crush behaviour of both monolithic aluminium cylinders and externally fibre reinforced aluminium cylinders. The research is based

  12. Time-based position estimation in monolithic scintillator detectors

    NARCIS (Netherlands)

    Tabacchini, V.; Borghi, G.; Schaart, D.R.

    2015-01-01

    Gamma-ray detectors based on bright monolithic scintillation crystals coupled to pixelated photodetectors are currently being considered for several applications in the medical imaging field. In a typical monolithic detector, both the light intensity and the time of arrival of the earliest

  13. Time-based position estimation in monolithic scintillator detectors

    NARCIS (Netherlands)

    Tabacchini, V.; Borghi, G.; Schaart, D.R.

    2015-01-01

    Gamma-ray detectors based on bright monolithic scintillation crystals coupled to pixelated photodetectors are currently being considered for several applications in the medical imaging field. In a typical monolithic detector, both the light intensity and the time of arrival of the earliest scintilla

  14. Time-based position estimation in monolithic scintillator detectors

    NARCIS (Netherlands)

    Tabacchini, V.; Borghi, G.; Schaart, D.R.

    2015-01-01

    Gamma-ray detectors based on bright monolithic scintillation crystals coupled to pixelated photodetectors are currently being considered for several applications in the medical imaging field. In a typical monolithic detector, both the light intensity and the time of arrival of the earliest scintilla

  15. A Monolithic Perovskite Structure for Use as a Magnetic Regenerator

    DEFF Research Database (Denmark)

    Pryds, Nini; Clemens, Frank; Menon, Mohan

    2011-01-01

    A La0.67Ca0.26Sr0.07Mn1.05O3 (LCSM) perovskite was prepared for the first time as a ceramic monolithic regenerator used in a regenerative magnetic refrigeration device. The parameters influencing the extrusion process and the performance of the regenerator, such as the nature of the monolith paste...

  16. Energy Absorption of Monolithic and Fibre Reinforced Aluminium Cylinders

    NARCIS (Netherlands)

    De Kanter, J.L.C.G.

    2006-01-01

    Summary accompanying the thesis: Energy Absorption of Monolithic and Fibre Reinforced Aluminium Cylinders by Jens de Kanter This thesis presents the investigation of the crush behaviour of both monolithic aluminium cylinders and externally fibre reinforced aluminium cylinders. The research is based

  17. Hydrogel coated monoliths for enzymatic hydrolysis of penicillin G

    NARCIS (Netherlands)

    De Lathouder, K.M.; Smeltink, M.W.; Straathof, A.J.J.; Paasman, M.A.; Van de Sandt, E.J.A.X.; Kapteijn, F.; Moulijn, J.A.

    2008-01-01

    The objective of this work was to develop a hydrogel-coated monolith for the entrapment of penicillin G acylase (E. coli, PGA). After screening of different hydrogels, chitosan was chosen as the carrier material for the preparation of monolithic biocatalysts. This protocol leads to active immobilize

  18. A new large area monolithic silicon telescope

    CERN Document Server

    Tudisco, S; Cabibbo, M; Cardella, G; De Geronimo, G; Di Pietro, A; Fallica, G; Figuera, P; Musumarra, A; Papa, M; Pappalardo, G S; Rizzo, F; Valvo, G

    1999-01-01

    A new prototype of large area (20x20 mm sup 2) monolithic silicon telescope with an ultrathin DELTA E stage (1 mu m) has been built and tested. A particular mask for the ground electrode has been developed to improve the charge collection reducing the induction between the E and DELTA E stages. A special designed preamplifier has been used for the readout of the signal from the DELTA E stage to overcome the problem of the large input capacitance (40 nF). A rather low energy threshold charge discrimination has been obtained. Small side effects due to the electric field deformation near the ground electrode were observed and quantified.

  19. Monolithic aerogels with nanoporous crystalline phases

    Science.gov (United States)

    Daniel, Christophe; Guerra, Gaetano

    2015-05-01

    High porosity monolithic aerogels with nanoporous crystalline phases can be obtained from syndiotactic polystyrene and poly(2,6-dimethyl-1,4-phenylene)oxide thermoreversible gels by removing the solvent with supercritical CO2. The presence of crystalline nanopores in the aerogels based on these polymers allows a high uptake associated with a high selectivity of volatile organic compounds from vapor phase or aqueous solutions even at very low activities. The sorption and the fast kinetics make these materials particularly suitable as sorption medium to remove traces of pollutants from water and moist air.

  20. Sonochemical Reactors.

    Science.gov (United States)

    Gogate, Parag R; Patil, Pankaj N

    2016-10-01

    Sonochemical reactors are based on the generation of cavitational events using ultrasound and offer immense potential for the intensification of physical and chemical processing applications. The present work presents a critical analysis of the underlying mechanisms for intensification, available reactor configurations and overview of the different applications exploited successfully, though mostly at laboratory scales. Guidelines have also been presented for optimum selection of the important operating parameters (frequency and intensity of irradiation, temperature and liquid physicochemical properties) as well as the geometric parameters (type of reactor configuration and the number/position of the transducers) so as to maximize the process intensification benefits. The key areas for future work so as to transform the successful technique at laboratory/pilot scale into commercial technology have also been discussed. Overall, it has been established that there is immense potential for sonochemical reactors for process intensification leading to greener processing and economic benefits. Combined efforts from a wide range of disciplines such as material science, physics, chemistry and chemical engineers are required to harness the benefits at commercial scale operation.

  1. Design of heterogeneous catalysts

    DEFF Research Database (Denmark)

    Frey, Anne Mette

    was inspired by a computational screening, suggesting that alloys such as Ni-Fe, Co-Ni, and Co-Fe should show superior activity to the industrially used nickel catalyst. Especially the Ni-Fe system was considered to be interesting, since such alloy catalysts should be both more active and cheaper than the Ni...... well, and the best catalyst prepared had a C5+ yield almost a factor of two higher than a standard air calcined Co catalyst. In the NH3-SCR reaction it is desirable to develop an active and stable catalyst for NOx removal in automotive applications, since the traditionally used vanadium-based catalyst...... pose an environmental risk. The focus was put on iron-containing zeolite catalysts, since these recently have shown great potential as catalysts for the process. A number of different zeolites were compared. BEA was found to be the most active, thus focus was put on this material. Different preparation...

  2. Gas pollutant cleaning by a membrane reactor

    Directory of Open Access Journals (Sweden)

    Kaldis Sotiris

    2006-01-01

    Full Text Available An alternative technology for the removal of gas pollutants at the integrated gasification combined cycle process for power generation is the use of a catalytic membrane reactor. In the present study, ammonia decomposition in a catalytic reactor, with a simultaneous removal of hydrogen through a ceramic membrane, was investigated. A Ni/Al2O3 catalyst was prepared by the dry and wet impregnation method and characterized by the inductively coupled plasma method, scanning electron microscopy, X-ray diffraction, and N2 adsorption before and after activation. Commercially available a-Al2O3 membranes were also characterized and the permeabilities and permselectivities of H2, N2, and CO2 were measured by the variable volume method. In parallel with the experimental analysis, the necessary mathematical models were developed to describe the operation of the catalytic membrane reactor and to compare its performance with the conventional reactor. .

  3. Membrane reactor technology for ultrapure hydrogen production

    Energy Technology Data Exchange (ETDEWEB)

    Patil, C.S.

    2005-11-17

    The main objectives of this thesis are (1) to compare different reactor types and assess the feasibility of operation; (2) to develop and design a novel reactor concept based on the integration of perm-selective hydrogen and oxygen membranes; and (3) to give an experimental proof of principle of the developed reactor concept. In Chapter 2, available perm-selective hydrogen and oxygen membranes are reviewed. The focus is on the reactor concepts using these membranes and commercial developments that have taken place. In Chapter 3, the feasibility of performing autothermal membrane reforming in a packed bed membrane reactor with perm-selective hydrogen membrane is investigated based on detailed two-dimensional non-isothermal reactor modelling. In Chapter 4, an alternative reactor concept is developed for the autothermal reforming of methane integrating both hydrogen and oxygen perm-selective membranes. In Chapter 5, experimental work on the perm-selective hydrogen membranes that are used in the top section of the proposed reactor concept has been elaborated. These membranes, procured from a commercial supplier, are tested for their perm-selectivity and the permeability of hydrogen at different temperature and hydrogen partial pressures. Using the flux data a lumped flux expression is developed which is subsequently used in the pilot scale reactor design (Chapter 7). In Chapter 6, the kinetic rate measurements for SRM on a highly active Shell CPO catalyst are described. A kinetic rate expression for the steam reforming/ water gas shift top section of the proposed novel reactor concept is developed. The bottom section of this reactor is essentially at thermodynamic equilibrium because of highly active CPO catalyst and high temperatures and hence a detailed kinetic investigation for this section is not undertaken. In Chapter 7, a single membrane prototype of the top section is tested experimentally followed by a scale-up and design to a pilot scale unit with 10 Pd

  4. Improved activity and durability of Rh-based three-way catalyst under diverse aging atmospheres by ZrO2 support.

    Science.gov (United States)

    Cao, Yidan; Ran, Rui; Wu, Xiaodong; Zhao, Baohuai; Weng, Duan

    2017-02-01

    The catalytic activity and durability of Rh/ZrO2 catalyst were investigated compared with Rh/Al2O3 catalyst under diverse aging atmospheres, including lean, rich and lean-rich cyclic aging atmospheres, to simulate the real working conditions of three-way catalyst. Oxidation states and microstructures of rhodium species were investigated to correlate with the catalytic performance of the catalysts. The catalytic performance and durability of the Rh catalyst under diverse aging atmospheres were drastically enhanced by ZrO2 support. ZrO2 support was confirmed to be able to effectively inhibit rhodium sintering even under diverse aging conditions. It can also successfully keep Rh species in an active low-valence state on the surface of the catalyst. The superiority of ZrO2 support compared to Al2O3 was verified by the Rh-based monolith catalyst.

  5. 助剂对Co/Al2O3催化剂浆态床费托合成反应性能影响%Effect of promoters on the performance of Co/Al2O3 catalysts for Fischer-Tropsch synthesis in slurry reactors

    Institute of Scientific and Technical Information of China (English)

    孙燕; 孙启文; 蒋凡凯; 张宗森; 刘继森

    2012-01-01

    The effect of ZrO2, Ru and/or Pt promoters on the structure and performance of Co/Al2O3 catalysts for Fischer-Tropsch synthesis in a slurry reactor was investigated. The results indicated that ZrO2 modification may prevent or reduce the formation of CoAl2O4 phase on the catalysts and improve the reduction of cobalt species, which is beneficial to the increase of the catalytic activity, the decrease of methane selectivity, as well as the improvement of C5+ selectivity. Small amounts of ruthenium and platinum as promoter are able to lower the reduction temperatures of cobalt species (Co3O4→CoO and CoO→Co°) and to get a high reduction extent; as a result, the catalysts promoted with noble metals exhibit much higher activity in CO hydrogenation. Moreover, the impregnation sequence of various components also has an important influence on the performance of resultant catalysts in Fischer-Tropsch synthesis. Impregnation of γ-Al2O3 with Zr at first, the formation of irreducible cobalt aluminate can be prevented; co-impregnation of γ-A12O3 with Co and Ru can enhance the interaction between cobalt and ruthenium, which benefits to the reduction of cobalt oxides; sequential impregnation of γ-Al2O3 with Co and Pt is beneficial to the dispersion of cobalt species. As a result, the sequentially impregnated catalyst Co-Pt-ZrO2/Al2O3 performs excellently in the Fischer-Tropsch synthesis.%考察了ZrO2、Ru或Pt助剂对Co/Al2O3催化剂结构及浆态床费托合成反应性能的影响.实验结果表明,添加ZrO2助剂可阻止或降低难还原铝酸钴的形成、促进催化剂的还原、提高Co/Al2O3催化剂对费托合成反应的催化活性、降低甲烷选择性并提高C5+烃选择性.H2-TPR表征结果表明,少量Ru或Pt助剂均能降低Co-ZrO2/Al2O3催化剂中钴物种还原温度(Co3O4→CoO和CoO→Co0),提高催化剂的还原度,催化剂呈现出良好的CO加氢反应活性.此外,催化剂组分间浸渍次序对费托合成反应性

  6. Influence of pretreatment condition of metal support on performance of metal supported hexaaluminate catalyst for methane combustion%金属载体预处理条件对催化燃烧用整体式六铝酸盐催化剂性能的影响

    Institute of Scientific and Technical Information of China (English)

    翟彦青; 李鑫钢; 李永丹

    2005-01-01

    Catalytic combustion of methane is one of the most promising processes to generate environmentally clean energy. Hexaaluminate (HA) monolithic catalyst is regarded as one of the potential catalytic materials under high temperature condition. In this work, the influence of pretreatment method of metal support (FeCr alloy) on the performance of metal supported hexaaluminate catalyst for methane combustion was studied firstly.

  7. Processing and characterization of multi-cellular monolithic bioceramics for bone regenerative scaffolds

    Science.gov (United States)

    Ari-Wahjoedi, Bambang; Ginta, Turnad Lenggo; Parman, Setyamartana; Abustaman, Mohd Zikri Ahmad

    2014-10-01

    Multicellular monolithic ceramic body is a ceramic material which has many gas or liquid passages partitioned by thin walls throughout the bulk material. There are many currently known advanced industrial applications of multicellular ceramics structures i.e. as supports for various catalysts, electrode support structure for solid oxide fuel cells, refractories, electric/electronic materials, aerospace vehicle re-entry heat shields and biomaterials for dental as well as orthopaedic implants by naming only a few. Multicellular ceramic bodies are usually made of ceramic phases such as mullite, cordierite, aluminum titanate or pure oxides such as silica, zirconia and alumina. What make alumina ceramics is excellent for the above functions are the intrinsic properties of alumina which are hard, wear resistant, excellent dielectric properties, resists strong acid and alkali attacks at elevated temperatures, good thermal conductivities, high strength and stiffness as well as biocompatible. In this work the processing technology leading to truly multicellular monolithic alumina ceramic bodies and their characterization are reported. Ceramic slip with 66 wt.% solid loading was found to be optimum as impregnant to the polyurethane foam template. Mullitic ceramic composite of alumina-sodium alumino disilicate-Leucite-like phases with bulk and true densities of 0.852 and 1.241 g cm-3 respectively, pore linear density of ±35 cm-1, linear and bulk volume shrinkages of 7-16% and 32 vol.% were obtained. The compressive strength and elastic modulus of the bioceramics are ≈0.5-1.0 and ≈20 MPa respectively.

  8. Pd Close Coupled Catalyst

    Institute of Scientific and Technical Information of China (English)

    Zhong Hua SHI; Mao Chu GONG; Yao Qiang CHEN

    2006-01-01

    A catalyst comprised novel high surface area alumina support was prepared to control emission of automobiles. The results showed that prepared catalyst could satisfy the requirements of a high performance close coupled catalyst for its good catalytic activity at low temperature and good stability at high temperature.

  9. Recovery of hydrogen from impurities using a palladium membrane reactor

    Energy Technology Data Exchange (ETDEWEB)

    Willms, R.S. [Los Alamos National Lab., NM (United States); Okuno, K. [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan)

    1993-12-01

    One of the important steps in processing the exhaust from a fusion reactor is recovering tritium which is incorporated into molecules such as water and methane. One device which may prove to be very effective for this purpose is a palladium membrane reactor. This is a reactor which incorporates a Pd/Ag membrane in the reactor geometry. Reactions such as water gas shift, steam reforming and methane cracking can be carried out over the reactor catalyst, and the product hydrogen can be simultaneously removed from the reacting mixture. Because product is removed, greater than usual conversions can be obtained. In addition ultrapure hydrogen is produced, eliminating the need for an additional processing step. A palladium membrane reactor has been built and tested with three different catalysts. Initial results with a Ni-based catalyst show that it is very effective at promoting all three reactions listed above. Under the proper conditions, hydrogen recoveries approaching 100% have been observed. This study serves to experimentally validate the palladium membrane reactor as potentially important tool for fusion fuel processing.

  10. Highly luminescent and ultrastable CsPbBr{sub 3} perovskite quantum dots incorporated into a silica/alumina monolith

    Energy Technology Data Exchange (ETDEWEB)

    Li, Zhichun; Kong, Long; Huang, Shouqiang; Li, Liang [School of Environmental Science and Engineering, Shanghai Jiao Tong University (China)

    2017-07-03

    We successfully prepared QDs incorporated into a silica/alumina monolith (QDs-SAM) by a simple sol-gel reaction of an Al-Si single precursor with CsPbBr{sub 3} QDs blended in toluene solution, without adding water and catalyst. The resultant transparent monolith exhibits high photoluminescence quantum yields (PLQY) up to 90 %, and good photostability under strong illumination of blue light for 300 h. We show that the preliminary ligand exchange of didodecyl dimethyl ammonium bromide (DDAB) was very important to protect CsPbBr{sub 3} QDs from surface damages during the sol-gel reaction, which not only allowed us to maintain the original optical properties of CsPbBr{sub 3} QDs but also prevented the aggregation of QDs and made the monolith transparent. The CsPbBr{sub 3} QDs-SAM in powder form was easily mixed into the resins and applied as color-converting layer with curing on blue light-emitting diodes (LED). The material showed a high luminous efficacy of 80 lm W{sup -1} and a narrow emission with a full width at half maximum (FWHM) of 25 nm. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  11. Direct conversion of methane to aromatics in a catalytic co-ionic membrane reactor

    National Research Council Canada - National Science Library

    Morejudo, S H; Zanón, R; Escolástico, S; Yuste-Tirados, I; Malerød-Fjeld, H; Vestre, P K; Coors, W G; Martínez, A; Norby, T; Serra, J M; Kjølseth, C

    2016-01-01

    .... We show that integration of an electrochemical BaZrO3-based membrane exhibiting both proton and oxide ion conductivity into an MDA reactor gives rise to high aromatic yields and improved catalyst stability...

  12. Monolithic columns in plant proteomics and metabolomics.

    Science.gov (United States)

    Rigobello-Masini, Marilda; Penteado, José Carlos Pires; Masini, Jorge Cesar

    2013-03-01

    Since "omics" techniques emerged, plant studies, from biochemistry to ecology, have become more comprehensive. Plant proteomics and metabolomics enable the construction of databases that, with the help of genomics and informatics, show the data obtained as a system. Thus, all the constituents of the system can be seen with their interactions in both space and time. For instance, perturbations in a plant ecosystem as a consequence of application of herbicides or exposure to pollutants can be predicted by using information gathered from these databases. Analytical chemistry has been involved in this scientific evolution. Proteomics and metabolomics are emerging fields that require separation, identification, and quantification of proteins, peptides, and small molecules of metabolites in complex biological samples. The success of this work relies on efficient chromatographic and electrophoretic techniques, and on mass spectrometric detection. This paper reviews recent developments in the use of monolithic columns, focusing on their applications in "top-down" and "bottom-up" approaches, including their use as supports for immobilization of proteolytic enzymes and their use in two-dimensional and multidimensional chromatography. Whereas polymeric columns have been predominantly used for separation of proteins and polypeptides, silica-based monoliths have been more extensively used for separation of small molecules of metabolites. Representative applications in proteomics and in analysis of plant metabolites are given and summarized in tables.

  13. Growth techniques for monolithic YBCO solenoidal magnets

    Energy Technology Data Exchange (ETDEWEB)

    Scruggs, S.J. [Texas Center for Superconductivity at University of Houston, 4800 Calhoun, Houston, TX 77204 (United States)]. E-mail: Sscruggs2@uh.edu; Putman, P.T. [Texas Center for Superconductivity at University of Houston, 4800 Calhoun, Houston, TX 77204 (United States); Fang, H. [Texas Center for Superconductivity at University of Houston, 4800 Calhoun, Houston, TX 77204 (United States); Alessandrini, M. [Texas Center for Superconductivity at University of Houston, 4800 Calhoun, Houston, TX 77204 (United States); Salama, K. [Texas Center for Superconductivity at University of Houston, 4800 Calhoun, Houston, TX 77204 (United States)

    2006-10-01

    The possibility of growing large single domain YBCO solenoids by the use of a large seed has been investigated. There are two known methods for producing a similar solenoid. This first is a conventional top seeded melt growth process followed by a post processing machining step to create the bore. The second involves using multiple seeds spaced around the magnet bore. The appeal of the new technique lies in decreasing processing time compared to the single seed technique, while avoiding alignment problems found in the multiple seeding technique. By avoiding these problems, larger diameter monoliths can be produced. Large diameter monoliths are beneficial because the maximum magnetic field produced by a trapped field magnet is proportional to the radius of the sample. Furthermore, the availability of trapped field magnets with large diameter could enable their use in applications that traditionally have been considered to require wound electromagnets, such as beam bending magnets for particle accelerators or electric propulsion. A comparison of YBCO solenoids grown by the use of a large seed and grown by the use of two small seeds simulating multiple seeding is made. Trapped field measurements as well as microstructure evaluation were used in characterization of each solenoid. Results indicate that high quality growth occurs only in the vicinity of the seeds for the multiple seeded sample, while the sample with the large seeded exhibited high quality growth throughout the entire sample.

  14. High surface area, high permeability carbon monoliths

    Energy Technology Data Exchange (ETDEWEB)

    Lagasse, R.R.; Schroeder, J.L. [Sandia National Labs., Albuquerque, NM (United States). Organic Materials Processing Dept.

    1994-12-31

    The goal of this work is to prepare carbon monoliths having precisely tailored pore size distribution. Prior studies have demonstrated that poly(acrylonitrile) can be processed into a precursor having tailored macropore structure. Since the macropores were preserved during pyrolysis, this synthetic process provided a route to porous carbon having macropores with size =0.1 to 10{mu}m. No micropores of size <2 nm could be detected in the carbon, however, by nitrogen adsorption. In the present work, the authors have processed a different polymer, poly(vinylidene chloride) into a macroporous precursor, Pyrolysis produced carbon monoliths having macropores derived from the polymer precursor as well as extensive microporosity produced during the pyrolysis of the polymer. One of these carbons had BET surface area of 1,050 m{sup 2}/g and about 1.2 cc/g total pore volume, with about 1/3 of the total pore volume in micropores and the remainder in 1{mu}m macropores. No mesopores in the intermediate size range could be detected by nitrogen adsorption. Carbon materials having high surface area as well as micron size pores have potential applications as electrodes for double layer supercapacitors containing liquid electrolyte, or as efficient media for performing chemical separations.

  15. Hydrothermal method for preparing calcium phosphate monoliths

    Directory of Open Access Journals (Sweden)

    García Carrodeguas Raúl

    2003-01-01

    Full Text Available A new hydrothermal route for preparing biphasic calcium phosphate monoliths is proposed. Firstly, a slurry of beta-tricalcium phosphate/ortho-phosphoric acid (b-TCP/H3PO4 is cast into the desired final shape and size to obtain a block composed of dicalcium phosphate dihydrate (DCPD and b-TCP. This block is then treated in 1.0 M Na2HPO4 at 60 °C in order to hydrolyze the DCPD into Ca10-x(HPO4x(PO4 6-x(OH2-x (CDHA and Ca8H2(PO46 .5H2O (OCP. The result is a monolithic piece which preserves the initial shape and size, but which is composed instead of CDHA, OCP, and b-TCP. During the initial stage, when the pH is slightly alkaline, the product of DCPD hydrolysis is CDHA. However, when a neutral or slightly acidic pH is reached OCP is formed. Test samples processed by this method showed complete conversion of DCPD into CDHA and OCP after 112 h of hydrolysis, and with a compressive strength of 16.2 MPa, similar to cancellous bone.

  16. Catastrophic failure of a monolithic zirconia prosthesis.

    Science.gov (United States)

    Chang, Jae-Seung; Ji, Woon; Choi, Chang-Hoon; Kim, Sunjai

    2015-02-01

    Recently, monolithic zirconia restorations have received attention as an alternative to zirconia veneered with feldspathic porcelain to eliminate chipping failures of veneer ceramics. In this clinical report, a patient with mandibular edentulism received 4 dental implants in the interforaminal area, and a screw-retained monolithic zirconia prosthesis was fabricated. The patient also received a maxillary complete removable dental prosthesis over 4 anterior roots. At the 18-month follow-up, all of the zirconia cylinders were seen to be fractured, and the contacting abutment surfaces had lost structural integrity. The damaged abutments were replaced with new abutments, and a new prosthesis was delivered with a computer-assisted design and computer-assisted manufacturing fabricated titanium framework with denture teeth and denture base resins. At the 6-month recall, the patient did not have any problems. Dental zirconia has excellent physical properties; however, care should be taken to prevent excessive stresses on the zirconia cylinders when a screw-retained zirconia restoration is planned as a definitive prosthesis.

  17. Microstructural Examination to Aid in Understanding Friction Bonding Fabrication Technique for Monolithic Nuclear Fuel

    Energy Technology Data Exchange (ETDEWEB)

    Karen L. Shropshire

    2008-04-01

    Monolithic nuclear fuel is currently being developed for use in research reactors, and friction bonding (FB) is a technique being developed to help in this fuel’s fabrication. Since both FB and monolithic fuel are new concepts, research is needed to understand the impact of varying FB fabrication parameters on fuel plate characteristics. This thesis research provides insight into the FB process and its application to the monolithic fuel design by recognizing and understanding the microstructural effects of varying fabrication parameters (a) FB tool load, and (b) FB tool face alloy. These two fabrication parameters help drive material temperature during fabrication, and thus the material properties, bond strength, and possible formation of interface reaction layers. This study analyzed temperatures and tool loads measured during those FB processes and examined microstructural characteristics of materials and bonds in samples taken from the resulting fuel plates. This study shows that higher tool load increases aluminum plasticization and forging during FB, and that the tool face alloy helps determine the tool’s heat extraction efficacy. The study concludes that successful aluminum bonds can be attained in fuel plates using a wide range of FB tool loads. The range of tool loads yielding successful uranium-aluminum bonding was not established, but it was demonstrated that such bonding can be attained with FB tool load of 48,900 N (11,000 lbf) when using a FB tool faced with a tungsten alloy. This tool successfully performed FB, and with better results than tools faced with other materials. Results of this study correlate well with results reported for similar aluminum bonding techniques. This study’s results also provide support and validation for other nuclear fuel development studies and conclusions. Recommendations are offered for further research.

  18. Estimation of Kinetic Parameters in an Automotive SCR Catalyst Model

    DEFF Research Database (Denmark)

    Åberg, Andreas; Widd, Anders; Abildskov, Jens;

    2016-01-01

    A challenge during the development of models for simulation of the automotive Selective Catalytic Reduction catalyst is the parameter estimation of the kinetic parameters, which can be time consuming and problematic. The parameter estimation is often carried out on small-scale reactor tests, or p...

  19. Irradiation Tests Supporting LEU Conversion of Very High Power Research Reactors in the US

    Energy Technology Data Exchange (ETDEWEB)

    Woolstenhulme, N. E.; Cole, J. I.; Glagolenko, I.; Holdaway, K. K.; Housley, G. K.; Rabin, B. H.

    2016-10-01

    The US fuel development team is developing a high density uranium-molybdenum alloy monolithic fuel to enable conversion of five high-power research reactors. Previous irradiation tests have demonstrated promising behavior for this fuel design. A series of future irradiation tests will enable selection of final fuel fabrication process and provide data to qualify the fuel at moderately-high power conditions for use in three of these five reactors. The remaining two reactors, namely the Advanced Test Reactor and High Flux Isotope Reactor, require additional irradiation tests to develop and demonstrate the fuel’s performance with even higher power conditions, complex design features, and other unique conditions. This paper reviews the program’s current irradiation testing plans for these moderately-high irradiation conditions and presents conceptual testing strategies to illustrate how subsequent irradiation tests will build upon this initial data package to enable conversion of these two very-high power research reactors.

  20. Enhanced dibenzothiophene biodesulfurization in a microchannel reactor.

    Science.gov (United States)

    Noda, Ken-Ichi; Kogure, Tomonari; Irisa, Shiro; Murakami, Yuji; Sakata, Minoru; Kuroda, Akio

    2008-03-01

    A microchannel reactor system was used in a biodesulfurization process in which the rate of biodesulfurization in the oil/water phase of the microchannel reaction was more than nine-fold that in a batch (control) reaction. In addition, the microchannel reaction system using a bacterial cell suspension degraded alkylated dibenzothiophene that was not degraded by the batch reaction system. This work provides a foundation for the application of a microchannel reactor system consisting of biological catalysts using an oil/water phase reaction.

  1. Sequential reactions directed by core/shell catalytic reactors.

    Science.gov (United States)

    Wei, Yanhu; Soh, Siowling; Apodaca, Mario M; Kim, Jiwon; Grzybowski, Bartosz A

    2010-04-09

    Millimeter-sized reactor particles made of permeable polymer doped with catalysts arranged in a core/shell fashion direct sequences of chemical reactions (e.g., alkyne coupling followed by hydrogenation or hydrosilylation followed by hydrogenation). Spatial compartmentalization of catalysts coupled with the diffusion of substrates controls reaction order and avoids formation of byproducts. The experimentally observed yields of reaction sequences are reproduced by a theoretical model, which accounts for the reaction kinetics and the diffusion of the species involved.

  2. Study of cerium-promoted rhodium alumina catalyst as a steam reforming catalyst for treatment of spent solvents

    Institute of Scientific and Technical Information of China (English)

    Hee-Chul Yang; Min-Woo Lee; Ho-Sang Hwang; Jei-Kwon Moon; Dong-Yong Chung

    2014-01-01

    This study attempted to develop an appropriate catalyst used for the steam reforming of gasified spent solvents. Rh2O3/ CeO2-Al2O3 catalysts with various CeO2 loadings were prepared and heated at different temperatures of 500 and 800 ºC, and their surface properties were studied using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron mi-croscopy (TEM), temperature programmed reduction (TPR) and Brumauer-Emmett-Teller (BET) analyses. Rhodium existed in the form of Rh2O3, regardless of the sample composition as well as the heating temperature. In the tested range of cerium addition (up to 12 times the rhodium mass), no significant changes in BET surface areas and binding energy corresponding to Rh 3d5/2were observed. Instead, the addition of cerium led to a greatly enhanced dispersion of rhodium nanoparticles, and no agglomeration of rhodium was observed for samples heated even at 800 ºC. Honeycomb monolith rhodium catalysts promoted with cerium were fabricated and tested for the steam reforming of a gasified spent solvent, mainly consisting of butylene (C4H8). The test results suggested that a ce-rium-promoted rhodium catalyst could be used as an appropriate reforming catalyst for treating low-quality non-methane hydrocar-bons without the formation of coke at high temperatures of up to 900 ºC.

  3. The development of precipitated iron catalysts with improved stability; Final report, September 1987--September 1992

    Energy Technology Data Exchange (ETDEWEB)

    Abrevaya, H.

    1993-12-27

    Precipitated iron catalysts are expected to be used in next generation slurry reactors for large-scale production of transportation fuels from synthesis gas. These reactors are expected to operate at higher temperatures and lower H{sub 2}:CO ratios relative to the Sasol Arge reactor (Table 1A). The feasibility of using iron catalysts has been demonstrated under relatively mild Arge-type conditions but not under more severe slurry conditions. Possibly, an improvement in catalytic stability will be needed to make iron catalysts suitable for slurry operation. This program was aimed at identifying the chemical principles governing the deactivation of precipitated iron catalysts during Fischer-Tropsch synthesis and use of these chemical principles in the design of more stable catalysts. A new precipitated Fe catalyst was developed in this program for slurry reactor operation. The new Fe catalyst is predicted to perform slightly below the performance targets for slurry bubble column operation. Stability targets appear to be achievable. This catalyst did not noticeably deactivate during 1,740 hours on-stream. Compared to the selectivity target, an excess of 2% C{sub 1} + C{sub 2} was formed at 265{degrees}C. Based on the initial catalyst inventory in the autoclave, the catalyst seems to be short of the activity target by a factor of 1.8 at 265{degrees}C and 1.3 at 275{degrees}C. However, actual specific activities are likely to be closer to target because of catalyst inventory loss across the filter during the run and because catalytic activities were underestimated at low conversions.

  4. ATR LEU Monolithic Foil-Type Fuel with Integral Cladding Burnable Absorber – Neutronics Performance Evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Gray Chang

    2012-03-01

    The Advanced Test Reactor (ATR), currently operating in the United States, is used for material testing at very high neutron fluxes. Powered with highly enriched uranium (HEU), the ATR has a maximum thermal power rating of 250 MWth. Because of the large test volumes located in high flux areas, the ATR is an ideal candidate for assessing the feasibility of converting HEU driven reactor cores to low-enriched uranium (LEU) cores. The burnable absorber - 10B, was added in the inner and outer plates to reduce the initial excess reactivity, and to improve the peak ratio of the inner/outer heat flux. The present work investigates the LEU Monolithic foil-type fuel with 10B Integral Cladding Burnable Absorber (ICBA) design and evaluates the subsequent neutronics operating effects of this proposed fuel designs. The proposed LEU fuel specification in this work is directly related to both the RERTR LEU Development Program and the Advanced Test Reactor (ATR) LEU Conversion Project at Idaho National Laboratory (INL).

  5. 'Design of CO-O2 recombination catalysts for closed-cycle CO2 lasers'

    Science.gov (United States)

    Guinn, K.; Goldblum, S.; Noskowski, E.; Herz, R.

    1989-01-01

    Pulsed CO2 lasers have many applications in aeronautics, space research, weather monitoring and other areas. Full exploitation of the potential of these lasers is hampered by the dissociation of CO2 that occurs during laser operation. The development of closed-cycle CO2 lasers requires active CO-O2 recombination (CO oxidation) catalysts and design methods for implementation of catalysts inside lasers. This paper will discuss the performance criteria and constraints involved in the design of monolith catalyst configurations for use in a closed-cycle laser and will present a design study performed with a computerized design program that had been written. Trade-offs between catalyst activity and dimensions, flow channel dimensions, pressure drop, O2 conversion and other variables will be discussed.

  6. The influence of cladding on fission gas release from irradiated U-Mo monolithic fuel

    Science.gov (United States)

    Burkes, Douglas E.; Casella, Amanda J.; Casella, Andrew M.

    2017-04-01

    The monolithic uranium-molybdenum (U-Mo) alloy has been proposed as a fuel design capable of converting the world's highest power research reactors from use of high enriched uranium to low enriched uranium. However, a zirconium (Zr) diffusion barrier must be used to eliminate interactions that form between the U-Mo monolith and aluminum alloy 6061 (AA6061) cladding during fabrication and are enhanced during irradiation. One aspect of fuel development and qualification is to demonstrate an appropriate understanding of the extent of fission product release from the fuel under anticipated service environments. An exothermic reaction has previously been observed between the AA6061 cladding and Zr diffusion layer. In this paper, two fuel segments with different irradiation history were subjected to specified thermal profiles under a controlled atmosphere using a thermogravimetric/differential thermal analyzer coupled with a mass spectrometer inside a hot cell. Samples from each segment were tested with cladding and without cladding to investigate the effect, if any, that the exothermic reaction has on fission gas release mechanisms. Measurements revealed there is an instantaneous effect of the cladding/Zr exothermic reaction, but not necessarily a cumulative effect above approximately 973 K (700 °C). The mechanisms responsible for fission gas release events are discussed.

  7. Measurement of Fission Gas Release from Irradiated U-Mo Monolithic Fuel Samples

    Energy Technology Data Exchange (ETDEWEB)

    Burkes, Douglas; Casella, Amanda J.; Casella, Andrew M.; Luscher, Walter G.; Rice, Francine; Pool, Karl N.

    2015-06-01

    The uranium-molybdenum (U-Mo) alloy in a monolithic form has been proposed as one fuel design capable of converting some of the world’s highest power research reactors from the use of high enriched uranium (HEU) to low enriched uranium (LEU). One aspect of the fuel development and qualification process is to demonstrate appropriate understanding of the extent of fission product release from the fuel under anticipated service environments. An apparatus capable of annealing post-irradiated small-scale samples cut from larger fuel segments according to specified thermal profiles under a controlled atmosphere has been installed into a hot cell. Results show that optimized experimental parameters to investigate fission product release from small samples have been established. Initial measurements conducted on aluminum alloy clad uranium-molybdenum monolithic fuel samples reveal three clear fission gas release events over the temperature range of 30-1050 C. The mechanisms responsible for these events are discussed, and the results have been compared with available information in literature.

  8. Measurement of fission gas release from irradiated U–Mo monolithic fuel samples

    Energy Technology Data Exchange (ETDEWEB)

    Burkes, Douglas E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Casella, Amanda J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Casella, Andrew M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Luscher, Walter G. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Rice, Francine J. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Pool, Karl N. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2015-06-01

    The uranium–molybdenum (U-Mo) alloy in a monolithic form has been proposed as one fuel design capable of converting some of the world’s highest power research reactors from the use of high enriched uranium (HEU) to low enriched uranium (LEU). One aspect of the fuel development and qualification process is to demonstrate appropriate understanding of the extent of fission product release from the fuel under anticipated service environments. An apparatus capable of heating post-irradiated small-scale samples cut from larger fuel segments according to specified thermal profiles under a controlled atmosphere has been installed into a hot cell. Results show that optimized experimental parameters to investigate fission product release from small samples have been established. Initial measurements conducted on aluminum alloy clad uranium–molybdenum monolithic fuel samples reveal three clear fission gas release events over the temperature range of 30-1000 °C. The mechanisms responsible for these events are discussed, and the results have been compared with available information in the literature.

  9. Testing catalysts for production performance and runaway limits

    Energy Technology Data Exchange (ETDEWEB)

    Berty, I.J.; Berty, J.M.; Brinkeroff, P.T.; Chovan, T. (Berty Reaction Engineers, Ltd., Akron, OH (US))

    1989-11-01

    The results of laboratory catalyst tests, conducted in recycle reactors under fixed conditions of feed rate and composition and otherwise at average production conditions, permit the evaluation of catalyst performance for production reactors. These tests are performed in short steady-state runs at stepwise increasing temperatures until a specified product concentration is reached. From these results, in addition to performance evaluation, the thermal stability criteria of the reaction can also be calculated. This information is needed to maximize production within the thermal runaway limit. Since the thermal runaway limit, estimated from the catalyst test, does not contain assumptions on kinetics, the experimentally evaluated runaway limit can be used as a benchmark to help discriminate between kinetic models that were developed from other data sets. The evaluation of the performance as well as the thermal runaway limit is shown on actual experimental measurements made for the production of ethylene oxide by oxidation of ethylene.

  10. Deactivation by carbon of iron catalysts for indirect liquefaction

    Energy Technology Data Exchange (ETDEWEB)

    Bartholomew, C.H.

    1990-10-29

    This report describes recent progress in a fundamental, three-year investigation of carbon formation and its effects on the activity and selectivity of promoted iron catalysts for synthesis, the objectives of which are: determine rates and mechanisms of carbon deactivation of unsupported Fe and Fe/K catalysts during CO hydrogenation over a range of CO concentrations, CO:H{sub 2} ratios, and temperatures; model the rates of deactivation of the same catalysts in fixed-bed reactors. During the fourteenth quarter design of software for a computer-automated reactor system to be used in the kinetic and deactivation studies was continued. Further progress was made toward the completion of the control language, control routines, and software for operating this system. Progress was also made towards testing of the system hardware and software. 47 refs.

  11. Preparation and Characterization of Temperature-responsive Porous Monoliths

    Institute of Scientific and Technical Information of China (English)

    ZHANG, Rongyue; QI, Li; XIN, Peiyong; YANG, Gengliang; CHEN, Yi

    2009-01-01

    A new temperature-responsive porous monolith has been prepared by surface-initiated activators generated by electron transfer atom transfer radical polymerization (AGET ATRP) grafting poly(N-isopropylacrylamide) (PNIPAAm) within the pores of the porous polymer monolith. The grafting copolymerization was carried out by a method based on a continuous flow-through technique without special deoxygenation procedure needed in the general ATRP. The addition of ascorbic acid could counteract the oxidation effect of oxygen diffusing into the reaction system. The resulting grafted monolith was characterized by a mercury intrusion method and the size of macropore was 3.65 μm, which was suitable for flow through the monolith for HPLC. The thermally responsive property of the grafted monolith was evaluated by HPLC using steroids with various hydrophobicities as probes. Through determination of retention factor of each steroid on the grafted monolith at different temperatures using water as mobile phase, it was found that the slope of the plot of retention factor of each steroid versus the temperature changed around the low critical solution temperature (LCST, 32 ℃) of PNIPAAm in water. It was relative to the grafted PNIPAAm temperature sensitivity that a hydrophobic and hydrophilic alternation would take place around its LCST.Based on this thermally responsive property, the grafted monolith was used as stationary phase for HPLC and to separate the steroids using water as mobile phase by changing the column temperature. As a mobile phase, water is much better than organic solvents concerning the environment.

  12. Influence of different carbon monolith preparation parameters on pesticide adsorption

    Directory of Open Access Journals (Sweden)

    Vukčević Marija

    2013-01-01

    Full Text Available The capacity of carbon monolith for pesticide removal from water, and the mechanism of pesticide interaction with carbon surface were examined. Different carbon monolith samples were obtained by varying the carbonization and activation parameters. In order to examine the role of surface oxygen groups in pesticide adsorption, carbon monolith surface was functionalized by chemical treatment in HNO3, H2O2 and KOH. The surface properties of the obtained samples were investigated by BET surface area, pore size distribution and temperature-programmed desorption. Adsorption of pesticides from aqueous solution onto activated carbon monolith samples was studied by using five pesticides belonging to different chemical groups (acetamiprid, dimethoate, nicosulfuron, carbofuran and atrazine. Presented results show that higher temperature of carbonization and the amount of activating agent allow obtaining microporous carbon monolith with higher amount of surface functional groups. Adsorption properties of the activated carbon monolith were more readily affected by the amount of the surface functional groups than by specific surface area. Results obtained by carbon monolith functionalisation showed that π-π interactions were the main force for adsorption of pesticides with aromatic structure, while acidic groups play an important role in adsorption of pesticides with no aromatic ring in the chemical structure.

  13. Dynamic Simulation of Batch Photocatalytic Reactor (BPR) for Wastewater Treatment

    Science.gov (United States)

    Dutta, Suman

    2012-08-01

    Reactive dyes discharged from dyehouse causes a serious environmental problem. UV/TiO2 photocatalysis has been employed effectively for these organic dyes removal from dye-house effluent. This process produces less amount of non-toxic final product. In this paper a photocatalytic reactor has been designed for Reactive red 198 (RR198) removal from aqueous solution. The reactor is operating in batch mode. After each batch, TiO2 catalyst has been separated and recycled in the next batch. Mathematical model equation of this batch photocatalytic reactor (BPR) has been developed considering Langmuir-Hinshelwood kinetics. Simulation of BPR has been carried out using fourth order Runge-Kutta (RK) method and fifth order RK method (Butcher method). This simulation results can be used to develop an automatic photocatlytic reactor for industrial wastewater treatment. Catalyst activity decay and its effect on each batch have been incorporated in this model.

  14. Origin of low temperature deactivation of Ni5Ga3 nanoparticles as catalyst for methanol synthesis

    DEFF Research Database (Denmark)

    Gardini, Diego; Sharafutdinov, Irek; Damsgaard, Christian Danvad

    is subsequently increased, suggesting the presence of carbon containing species blocking the active sites of the alloy nanoparticles (Figure 1). Carbon deposition has furthermore been investigated by temperature programmed oxidation (TPO) of a deactivated catalyst in a fixed-bed reactor connected to a mass......-Ga alloys as active catalysts for methanol production from syngas mixtures and Ni-Ga nanoparticles supported on highly porous silica have been prepared using an incipient wetness impregnation technique from a solution of nickel and gallium nitrates [2]. Tests conducted in a fixed-bed reactor showed...... as catalyst for methanol production. Synthesis, followed by deactivation and a series of regeneration steps at increasing temperature in pure H2 has been carried out in a fixed-bed reactor connected to a gas chromatography system. In each regeneration step, CH4 is generated and the activity of the catalyst...

  15. Catalytic reactor

    OpenAIRE

    Sie, S.T.; Cybulski, A.; Moulijn, J.A

    2000-01-01

    PCT No. PCT/NL93/00231 Sec. 371 Date Jul. 21, 1995 Sec. 102(e) Date Jul. 21, 1995 PCT Filed Nov. 4, 1993 PCT Pub. No. WO94/09901 PCT Pub. Date May 11, 1994There is described a catalyst element (1) consisting of an integral whole having channels (2) extending therethrough. These channels (2) have, in circumferential sense of the cross section thereof, at least one concave wall portion and at least one convex wall portion, preferably provided by longitudinal projections (4) or grooves (7).

  16. Operation of FCC with mixtures of regenerated and deactivated catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Spretz, R.; Sedran, U. [INCAPE, FIQ, UNL - CONICET, Instituto de Investigaciones en Catalisis y Petroquimica, Santiago del Estero 2654, 3000 Santa Fe (Argentina)

    2001-07-13

    The operation of FCC with mixtures of coked and regenerated catalyst was studied with a riser simulator reactor on two equilibrium catalysts at 550C. The coked catalysts maintain an activity level that enables them to be used in the mixtures. The catalytic performances of the regenerated catalysts were used as references against which the behaviors of 25:75 and 50:50 (coked:regenerated) mixtures were compared. It was observed that overall catoil has to be increased to maintain conversion. While the yields of gases, gasoline and LCO showed to be independent of the operative mode, changes were observed in the selectivity to light olefins C4-C6 that are mainly due to changes in the yields of the isoparaffins in the groups. In turn, these changes could be the consequence of the resulting density of paired acid sites in the zeolite components on hydrogen transfer reactions, due to the contributions by the coked and regenerated portions of catalysts. Coke yields in mixtures of coked and regenerated catalysts are not higher, which would allow increasing catalyst circulation without impacting on heat balance. The particularities of this new operation of FCC are very dependent on catalyst properties.

  17. Using Mechanical Alloying to Create Bimetallic Catalysts for Vapor-Phase Carbon Nanofiber Synthesis

    Directory of Open Access Journals (Sweden)

    Laura Guevara

    2015-10-01

    Full Text Available Carbon nanofibers were generated over bimetallic catalysts in an atmospheric pressure chemical vapor deposition (APCVD reactor. Catalyst compositions of Fe 30 at%, Cu and Ni 30 at% and Cu were mechanically alloyed using high-energy ball milling over durations of 4, 8, 12, 16, and 20 h. The catalyst powders were then used to produce carbon nanofibers in ethylene and hydrogen (4:1 at temperatures of 500, 550, and 600 °C. The microstructures of the catalysts were characterized as a function of milling time as well as at deposition temperature. The corresponding carbon deposition rates were assessed and are correlated to the microstructural features of each catalyst. The milling process directly determines the performance of each catalyst toward carbon deposition, and both catalysts performed comparably to those made by traditional co-precipitation methods. Considerations in miscible and immiscible nanostructured alloy systems are discussed.

  18. Synthesis of carbon nanotubes by CCVD of natural gas using hydrotreating catalysts

    Directory of Open Access Journals (Sweden)

    Ahmed E. Awadallah

    2012-12-01

    Full Text Available Carbon nanotubes have been successfully synthesized using the catalytic chemical vapor deposition (CCVD technique over typical refining hydrotreating catalysts (hydrodesulfurization and hydrodenitrogenation containing Ni–Mo and Co–Mo supported on Al2O3 catalysts at 700°C in a fixed bed horizontal reactor using natural gas as a carbon source. The catalysts and the as-grown CNTs were characterized by transmission electron microscopy, HRTEM, X-ray diffraction patterns, EDX and TGA–DTG. The obtained data clarified that the Ni–Mo catalyst gives higher yield, higher purity and selectivity for CNTs compared to Co–Mo catalyst. XRD, TEM and TGA reveal also that the Ni–Mo catalyst produces mostly CNTs with different diameters whereas the Co–Mo catalyst produces largely amorphous carbon.

  19. Preliminary comparison of monolithic and aperture optics for XRMF

    Energy Technology Data Exchange (ETDEWEB)

    Havrilla, G.J.; Worley, C.G.

    1997-08-01

    Comparisons between standard aperture optics and a custom designed monolithic capillary x-ray optic for the Kevex Omicron are presented. The results demonstrate the feasibility of retrofitting an Omicron with a monolithic capillary. Increased flux is observed especially at lower energies which results in an increase in sensitivity and potentially an increase in spatial resolution. Alignment is a critical factor in achieving optimal performance of the monolithic capillary. Further improvements in flux output, spot size and overall sensitivity are expected with better alignment.

  20. On monolithic stability and reinforcement analysis of high arch dams

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Monolithic stability safety and reinforcement based on monolithic stability are very important for arch dam design.In this paper,the issue is addressed based on deformation reinforcement theory.In this approach,plastic complementary energy norm can be taken as safety Index for monolithic stability.According to deformation reinforcement theory,the areas where unbalanced force exists require reinforcement,and the required reinforcement forces are just the unbalanced forces with opposite direction.Results show that areas with unbalanced force mainly concentrate in dam-toes,dam-heels and faults.

  1. Hierarchically Structured Monolithic ZSM-5 through Macroporous Silica Gel Zeolitization

    Institute of Scientific and Technical Information of China (English)

    Lei Qian; Zhao Tianbo; Li Fengyan; Zong Baoning; Tong Yangchuan

    2006-01-01

    The hierarchically structured ZSM-5 monolith was prepared through transforming the skeletons of the macroporous silica gel into ZSM-5 by the steam-assisted conversion method. The morphology and monolithic shapes of macroporous silica gel were well preserved. The hierarchically structured ZSM-5 monolith exhibited the hierarchical porosity, with mesopores and macropores existing inside the macroporous silica gel, and micropores formed by the ZSM-5. The products have been characterized properly by using the XRD, SEM and N2 adsorption-desorption methods.

  2. Preparation of carbon monoliths from orange peel for NOx retention

    Directory of Open Access Journals (Sweden)

    Liliana Giraldo

    2014-12-01

    Full Text Available A series of monoliths are prepared from orange peels and chemically activated with H3PO4, KOH, ZnCl2, and water vapor without a binder. The monoliths were characterized by N2 adsorption-desorption isotherms at 77 K, Boehm titrations and XPS. Thereafter, monoliths were tested for their ability to establish NOx retention. The results show that the retention capacities of NOx were a function of the textural properties and chemistries. The carbons synthesized with ZnCl2 and KOH retained similar amounts of NOx.

  3. A decoupled monolithic projection method for natural convection problems

    Science.gov (United States)

    Pan, Xiaomin; Kim, Kyoungyoun; Lee, Changhoon; Choi, Jung-Il

    2016-06-01

    We propose an efficient monolithic numerical procedure based on a projection method for solving natural convection problems. In the present monolithic method, the buoyancy, linear diffusion, and nonlinear convection terms are implicitly advanced by applying the Crank-Nicolson scheme in time. To avoid an otherwise inevitable iterative procedure in solving the monolithic discretized system, we use a linearization of the nonlinear convection terms and approximate block lower-upper (LU) decompositions along with approximate factorization. Numerical simulations demonstrate that the proposed method is more stable and computationally efficient than other semi-implicit methods, preserving temporal second-order accuracy.

  4. Influence of geometrical and operational parameters on the performance of porous catalytic membrane reactors

    NARCIS (Netherlands)

    Aran, H.C.; Klooster, H.J.G.; Jani, J.M.; Wessling, M.; Lefferts, L.; Lammertink, R.G.H.

    2012-01-01

    In this study, porous membrane reactors with various characteristic length (inner diameter), controllable catalyst support thickness, active catalyst surface area and tunable wetting properties are described for heterogeneously catalyzed gas¿liquid¿solid (G¿L¿S) reactions. We developed porous cerami

  5. Low-temperature SCR of NO{sub x} with NH{sub 3} over carbon-ceramic supported catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Valdes-Solis, Teresa; Marban, Gregorio; Fuertes, Antonio B. [Instituto Nacional del Carbon (CSIC), c/Francisco Pintado Fe No. 26, 33011 Oviedo (Spain)

    2003-11-10

    A new method for preparing vanadium oxide supported on carbon-ceramic cellular monoliths is described. This includes a support oxidation step with HNO{sub 3}, followed by ionic exchange with a NaOH solution, equilibrium adsorption impregnation of VO{sup 2+} and thermal treatment. As a result an active catalyst for low-temperature selective catalytic reduction (SCR) reaction is obtained. The V-catalyst is more resistant to SO{sub 2} poisoning than the previously developed Mn-catalyst. Inhibition by water is reversible for both types of catalysts. Testing of the vanadium catalyst after subjecting it to the outlet gas stream of a power plant shows fast deactivation until constant residual activity is reached. Deactivation seems to be caused by arsenic poisoning and the formation of superficial sulphates.

  6. Monolithically Peltier-cooled laser diodes

    Energy Technology Data Exchange (ETDEWEB)

    Hava, S.; Hunsperger, R.G.; Sequeira, H.B.

    1984-04-01

    A new method of cooling a GaAs/GaAlAs laser in an optical integrated circuit or on a discrete chip, by adding an integral thermoelectric (Peltier) cooling and heat spreading device to the laser, is presented. This cooling both reduces and stabilizes the laser junction temperature to minimize such deleterious effects as wavelength drift due to heating. A unified description of the electrical and thermal properties of a monolithic semiconductor mesa structure is given. Here it is shown that an improvement in thermal characteristics is obtained by depositing a relatively thick metallic layer, and by using this layer as a part of an active Peltier structure. Experimental results reveal a 14-percent increase in emitted power (external quantum efficiency) due to passive heat spreading and a further 8-percent if its Peltier cooler is operated. Fabrication techniques used to obtain devices exhibiting the above performance characteristics are given. 21 references.

  7. LSST primary/tertiary monolithic mirror

    Science.gov (United States)

    Sebag, J.; Gressler, W.; Liang, M.; Neill, D.; Araujo-Hauck, C.; Andrew, J.; Angeli, G.; Cho, M.; Claver, C.; Daruich, F.; Gessner, C.; Hileman, E.; Krabbendam, V.; Muller, G.; Poczulp, G.; Repp, R.; Wiecha, O.; Xin, B.; Kenagy, K.; Martin, H. M.; Tuell, M. T.; West, S. C.

    2016-08-01

    At the core of the Large Synoptic Survey Telescope (LSST) three-mirror optical design is the primary/tertiary (M1M3) mirror that combines these two large mirrors onto one monolithic substrate. The M1M3 mirror was spin cast and polished at the Steward Observatory Mirror Lab at The University of Arizona (formerly SOML, now the Richard F. Caris Mirror Lab at the University of Arizona (RFCML)). Final acceptance of the mirror occurred during the year 2015 and the mirror is now in storage while the mirror cell assembly is being fabricated. The M1M3 mirror will be tested at RFCML after integration with its mirror cell before being shipped to Chile.

  8. A monolithic thin film electrochromic window

    Energy Technology Data Exchange (ETDEWEB)

    Goldner, R.B.; Arntz, F.O.; Berera, G.; Haas, T.E.; Wong, K.K. (Tufts Univ., Medford, MA (United States). Electro-Optics Technology Center); Wei, G. (Mobil Solar Energy Corp., Billerica, MA (United States)); Yu, P.C. (PPG Industries, Inc., Monroeville, PA (United States))

    1991-01-01

    Three closely related thin film solid state ionic devices that are potentially important for applications are: electrochromic smart windows, high energy density thin film rechargeable batteries, and thin film electrochemical sensors. Each usually has at least on mixed ion/electron conductor, an electron-blocking ion conductor, and an ion-blocking electron conductor, and many of the technical issues associated with thin film solid state ionics are common to all three devices. Since the electrochromic window has the added technical requirement of electrically-controlled optical modulation, (over the solar spectrum), and since research at the authors' institution has focused primarily on the window structure, this paper will address the electrochromic window, and particularly a monolithic variable reflectivity electrochromic window, as an illustrative example of some of the challenges and opportunities that are confronting the thin film solid state ionics community. 33 refs.

  9. A monolithic thin film electrochromic window

    Energy Technology Data Exchange (ETDEWEB)

    Goldner, R.B.; Arntz, F.O.; Berera, G.; Haas, T.E.; Wong, K.K. [Tufts Univ., Medford, MA (United States). Electro-Optics Technology Center; Wei, G. [Mobil Solar Energy Corp., Billerica, MA (United States); Yu, P.C. [PPG Industries, Inc., Monroeville, PA (United States)

    1991-12-31

    Three closely related thin film solid state ionic devices that are potentially important for applications are: electrochromic smart windows, high energy density thin film rechargeable batteries, and thin film electrochemical sensors. Each usually has at least on mixed ion/electron conductor, an electron-blocking ion conductor, and an ion-blocking electron conductor, and many of the technical issues associated with thin film solid state ionics are common to all three devices. Since the electrochromic window has the added technical requirement of electrically-controlled optical modulation, (over the solar spectrum), and since research at the authors` institution has focused primarily on the window structure, this paper will address the electrochromic window, and particularly a monolithic variable reflectivity electrochromic window, as an illustrative example of some of the challenges and opportunities that are confronting the thin film solid state ionics community. 33 refs.

  10. Machining distortion prediction of aerospace monolithic components

    Institute of Scientific and Technical Information of China (English)

    Yun-bo BI; Qun-lin CHENG; Hui-yue DONG; Ying-lin KE

    2009-01-01

    To predict the distortion of aerospace monolithic components.a model is established to simulate the numerical control (NC)milling process using 3D finite element method(FEM).In this model,the cutting layer is simplified firstly.Then,the models of cutting force and cutting temperature are established to gain the cutting loads,which are applied to the mesh model of the part.Finally,a prototype of machining simulation environment is developed to simulate the milling process of a spar.Key factors influencing the distortion,such as initial residual stress,cutting loads,fixture layout,cutting sequence,and tool path are considered all together.The total distortion of the spar is predicted and an experiment is conducted to validate the numerical results.It is found that the maximum discrepancy between the simulation results and experiment values is 19.0%

  11. Solid oxide fuel cell having monolithic core

    Science.gov (United States)

    Ackerman, J. P.; Young, J. E.

    1983-10-01

    A solid oxide fuel cell is described for electrochemically combining fuel and oxidant for generating galvanic output, wherein the cell core has an array of electrolyte and interconnect walls that are substantially devoid of any composite inert materials for support. The core is monolithic, where each electrolyte wall consists of thin layers of cathode and anode materials sandwiching a thin layer of electrolyte material. The electrolyte walls are arranged and backfolded between adjacent interconnect walls operable to define a plurality of core passageways alternately arranged where the inside faces have only the anode material or only the cathode material exposed. Each layer of the electrolyte and interconnect materials 0.002 to 0.01 cm thick; and each layer of the cathode and anode materials is 0.002 to 0.05 cm thick.

  12. Silver deposition on chemically treated carbon monolith

    Directory of Open Access Journals (Sweden)

    Jovanović Zoran M.

    2009-01-01

    Full Text Available Carbon monolith was treated with HNO3, KOH and H2O2. Effects of these treatments on the surface functional groups and on the amount of silver deposited on the CM surface were studied by temperature programmed desorption (TPD and atomic absorption spectrometry (AAS. As a result of chemical treatment there was an increase in the amount of surface oxygen complexes. The increase in the amount of silver deposit is proportional to the amount of surface groups that produce CO under decomposition. However, the high amount of CO groups, decomposing above 600°C, induces the smaller Ag crystallite size. Therefore, the high temperature CO evolving oxides are, most likely, the initial centers for Ag deposition.

  13. Characterization of Deactivated Bio-oil Hydrotreating Catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Huamin; Wang, Yong

    2015-10-06

    Deactivation of bio-oil hydrotreating catalysts remains a significant challenge because of the poor quality of pyrolysis bio-oil input for hydrotreating and understanding their deactivation mode is critical to developing improved catalysts and processes. In this research, we developed an understanding of the deactivation of two-step bio-oil hydrotreating catalysts (sulfided Ru/C and sulfided CoMo/C) through detailed characterization of the catalysts using various complimentary analytical techniques. Severe fouling of both catalysts by carbonaceous species was the major form of deactivation, which is consistent with the significant loss of surface area and pore volume of both deactivated catalysts and the significant increase of the bulk density. Further analysis of the carbonaceous species by thermogravimetric analysis and x-ray photoelectron spectroscopy indicated that the carbonaceous species was formed by condensation reaction of active species such as sugars and sugar derivatives (aldehydes and ketones) in bio-oil feedstock during bio-oil hydrotreating under the conditions and catalysts used. Microscopy results did not show metal sintering of the Ru/C catalyst. However, X-ray diffraction indicated a probable transformation of the highly-active CoMoS phase in the sulfided CoMo/C catalyst to Co8S9 and MoS2 phase with low activity. Loss of the active site by transport of inorganic elements from the bio-oil and the reactor construction material onto the catalyst surface also might be a cause of deactivation as indicated by elemental analysis of spent catalysts.

  14. Irradiated microstructure of U-10Mo monolithic fuel plate at very high fission density

    Energy Technology Data Exchange (ETDEWEB)

    Gan, J.; Miller, B. D.; Keiser, D. D.; Jue, J. F.; Madden, J. W.; Robinson, A. B.; Ozaltun, H.; Moore, G.; Meyer, M. K.

    2017-08-01

    Monolithic U-10Mo alloy fuel plates with Al-6061 cladding are being developed for use in research and test reactors as low enrichment fuel (< 20% U-235 enrichment) as a result of its high uranium loading capacity compared to that of U-7Mo dispersion fuel. These fuel plates contain a Zr diffusion barrier between the U-10Mo fuel and Al-6061 cladding that suppresses the interaction between the U-Mo fuel foil and Al alloy cladding that is known to be problematic under irradiation. This paper discusses the TEM results of the U-10Mo/Zr/Al6061 monolithic fuel plate (Plate ID: L1P09T, ~ 59% U-235 enrichment) irradiated in Advanced Test Reactor at Idaho National Laboratory as part of RERTR-9B irradiation campaign with an unprecedented high local fission density of 9.8E+21 fissions/cm3. The calculated fuel foil centerline temperature at the beginning of life and the end of life is 141 and 194 C, respectively. A total of 5 TEM lamellas were prepared using focus ion beam lift-out technique. The estimated U-Mo fuel swelling, based on the fuel foil thickness change from SEM, is approximately 76%. Large bubbles (> 1 µm) are distributed evenly in U-Mo and interlink of these bubbles is evident. The average size of subdivided grains at this fission density appears similar to that at 5.2E+21 fissions/cm3. The measured average Mo and Zr content in the fuel matrix is ~ 30 at% and ~ 7 at%, respectively, in general agreement with the calculated Mo and Zr from fission density.

  15. An easily regenerable enzyme reactor prepared from polymerized high internal phase emulsions

    Energy Technology Data Exchange (ETDEWEB)

    Ruan, Guihua, E-mail: guihuaruan@hotmail.com [Guangxi Key Laboratory of Electrochemical and Magnetochemical Functional Materials, College of Chemistry and Bioengineering, Guilin University of Technology, Guangxi 541004 (China); Guangxi Collaborative Innovation Center for Water Pollution Control and Water Safety in Karst Area, Guilin University of Technology, Guilin 541004 (China); Wu, Zhenwei; Huang, Yipeng; Wei, Meiping; Su, Rihui [Guangxi Key Laboratory of Electrochemical and Magnetochemical Functional Materials, College of Chemistry and Bioengineering, Guilin University of Technology, Guangxi 541004 (China); Du, Fuyou, E-mail: dufu2005@126.com [Guangxi Key Laboratory of Electrochemical and Magnetochemical Functional Materials, College of Chemistry and Bioengineering, Guilin University of Technology, Guangxi 541004 (China); Guangxi Collaborative Innovation Center for Water Pollution Control and Water Safety in Karst Area, Guilin University of Technology, Guilin 541004 (China)

    2016-04-22

    A large-scale high-efficient enzyme reactor based on polymerized high internal phase emulsion monolith (polyHIPE) was prepared. First, a porous cross-linked polyHIPE monolith was prepared by in-situ thermal polymerization of a high internal phase emulsion containing styrene, divinylbenzene and polyglutaraldehyde. The enzyme of TPCK-Trypsin was then immobilized on the monolithic polyHIPE. The performance of the resultant enzyme reactor was assessed according to the conversion ability of N{sub α}-benzoyl-L-arginine ethyl ester to N{sub α}-benzoyl-L-arginine, and the protein digestibility of bovine serum albumin (BSA) and cytochrome (Cyt-C). The results showed that the prepared enzyme reactor exhibited high enzyme immobilization efficiency and fast and easy-control protein digestibility. BSA and Cyt-C could be digested in 10 min with sequence coverage of 59% and 78%, respectively. The peptides and residual protein could be easily rinsed out from reactor and the reactor could be regenerated easily with 4 M HCl without any structure destruction. Properties of multiple interconnected chambers with good permeability, fast digestion facility and easily reproducibility indicated that the polyHIPE enzyme reactor was a good selector potentially applied in proteomics and catalysis areas. - Graphical abstract: Schematic illustration of preparation of hypercrosslinking polyHIPE immobilized enzyme reactor for on-column protein digestion. - Highlights: • A reactor was prepared and used for enzyme immobilization and continuous on-column protein digestion. • The new polyHIPE IMER was quite suit for protein digestion with good properties. • On-column digestion revealed that the IMER was easy regenerated by HCl without any structure destruction.

  16. Effect of Electric Discharge on Properties of Nano-Particulate Catalyst for Plasma-Catalysis.

    Science.gov (United States)

    Lee, Chung Jun; Kim, Jip; Kim, Taegyu

    2016-02-01

    Heterogeneous catalytic processes have been used to produce hydrogen from hydrocarbons. However, high reforming temperature caused serious catalyst deteriorations and low energy efficiency. Recently, a plasma-catalyst hybrid process was used to reduce the reforming temperature and to improve the stability and durability of reforming catalysts. Effect of electric discharges on properties of nanoparticulate catalysts for plasma-catalysis was investigated in the present study. Catalyst-bed porosity was varied by packing catalyst beads with the different size in a reactor. Discharge power and onset voltage of the plasma were measured as the catalyst-bed porosity was varied. The effect of discharge voltage, frequency and voltage waveforms such as the sine, pulse and square was investigated. We found that the optimal porosity of the catalyst-bed exists to maximize the electric discharge. At a low porosity, the electric discharge was unstable to be sustained because the space between catalysts got narrow nearly close to the sheath region. On the other hand, at a high porosity, the electric discharge became weak because the plasma was not sufficient to interact with the surface of catalysts. The discharge power increased as the discharge voltage and frequency increased. The square waveform was more efficient than the sine and pulse one. At a high porosity, however, the effect of the voltage waveform was not considerable because the space between catalysts was too large for plasma to interact with the surface of catalysts.

  17. Catalyst Alloys Processing

    Science.gov (United States)

    Tan, Xincai

    2014-10-01

    Catalysts are one of the key materials used for diamond formation at high pressures. Several such catalyst products have been developed and applied in China and around the world. The catalyst alloy most widely used in China is Ni70Mn25Co5 developed at Changsha Research Institute of Mining and Metallurgy. In this article, detailed techniques for manufacturing such a typical catalyst alloy will be reviewed. The characteristics of the alloy will be described. Detailed processing of the alloy will be presented, including remelting and casting, hot rolling, annealing, surface treatment, cold rolling, blanking, finishing, packaging, and waste treatment. An example use of the catalyst alloy will also be given. Industrial experience shows that for the catalyst alloy products, a vacuum induction remelt furnace can be used for remelting, a metal mold can be used for casting, hot and cold rolling can be used for forming, and acid pickling can be used for metal surface cleaning.

  18. Flame spray deposition of porous catalysts on surfaces and in microsystems

    DEFF Research Database (Denmark)

    Thybo, Susanne; Jensen, Søren; Johansen, Johnny;

    2004-01-01

    . With shadow masks, porous catalyst layers can be deposited selectively into microchannels. Using Au/TiO$_2$ as test catalyst and CO-oxidation as test reaction, it is found that the apparent activation energy of the deposited catalyst is similar to what is normally seen for supported gold catalysts...... in the literature. The surface area of the deposited material is more than twice as large as when the flame-produced material is collected on a filter at the outlet of the flame reactor unit....

  19. A Promising MoOx-based Catalyst for n-Heptane Isomerization

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The SiO2 and γ-Al2O3 supported MoOx catalyst and a MoOx-SiO2 catalyst have been studied in a conventional fixed-bed flow reactor for n-alkanes isomerization. It is shown that the MoOx-SiO2 catalyst with SiO2 framework, in which the bulk MoOx phase is large enough to form typical mesoporous structure, is promising in terms of its advantages of both improved mechanical strength and high catalytic properties over the supported MoOx and bulk MoOx catalyst.

  20. Monolithic Rare Earth Doped PTR Glass Laser Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The main goal of the project is to demonstrate the feasibility of a monolithic solid state laser on the basis of PTR glass co-doped with luminescent rare earth ions....

  1. Application of monolithic chromatographic supports in virus research.

    Science.gov (United States)

    Krajacic, Mladen; Ravnikar, Maja; Štrancar, Aleš; Gutiérrez-Aguirre, Ion

    2017-05-12

    Key properties of monolithic chromatographic supports, make them suitable for separation and/or concentration of large biomolecules, especially virus particles and viral genomes. One by one, the studies that have been completed so far, contributed to the knowledge that monolith chromatography has hardly any limitation to be applied in virus research. Viruses of different sizes, possessing icosahedral structure and symmetrical morphology, as well as rod-shaped or filamentous viruses with helical structure, even enveloped ones, all of them could be successfully managed by means of monolith chromatography. Same is true for viral genomes, primarily when being distinct from other nucleic acid forms present in a host cell. This review is exclusively focused on viruses. It describes the application of monolith chromatography to different problematics within the virus research field. The reviewed achievements offer new possibilities and trigger new aspects in virology. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Monolithic Perovskite Silicon Tandem Solar Cells with Advanced Optics

    Energy Technology Data Exchange (ETDEWEB)

    Goldschmidt, Jan C.; Bett, Alexander J.; Bivour, Martin; Blasi, Benedikt; Eisenlohr, Johannes; Kohlstadt, Markus; Lee, Seunghun; Mastroianni, Simone; Mundt, Laura; Mundus, Markus; Ndione, Paul; Reichel, Christian; Schubert, Martin; Schulze, Patricia S.; Tucher, Nico; Veit, Clemens; Veurman, Welmoed; Wienands, Karl; Winkler, Kristina; Wurfel, Uli; Glunz, Stefan W.; Hermle, Martin

    2016-11-14

    For high efficiency monolithic perovskite silicon tandem solar cells, we develop low-temperature processes for the perovskite top cell, rear-side light trapping, optimized perovskite growth, transparent contacts and adapted characterization methods.

  3. Effect of accelerated aging on translucency of monolithic zirconia

    Directory of Open Access Journals (Sweden)

    O. Abdelbary

    2016-12-01

    Conclusion: Thickness of zirconia has significant effect on translucency. Aging has significant effect on thinner sections of zirconia. More research is required on zirconia towards making the material more translucent for its potential use as esthetic monolithic restoration.

  4. Monolithic CMOS pixel detector for international linear collider vertex detection

    Indian Academy of Sciences (India)

    J E Brau; O Igonkina; N Sinew; D Strom; C Baltay; W Emmet; H Neal; D Rabinowitz

    2007-12-01

    A monolithic CMS pixel detector is under development for an ILC experiment. This chronopixel array provides a time stamp resolution of one bunch crossing, a critical feature for background suppression. The status of this effort is summarized.

  5. Resin Catalyst Hybrids

    Institute of Scientific and Technical Information of China (English)

    S. Asaoka

    2005-01-01

    @@ 1Introduction: What are resin catalyst hybrids? There are typically two types of resin catalyst. One is acidic resin which representative is polystyrene sulfonic acid. The other is basic resin which is availed as metal complex support. The objective items of this study on resin catalyst are consisting of pellet hybrid, equilibrium hybrid and function hybrid of acid and base,as shown in Fig. 1[1-5].

  6. Cu-Zn-Al-Zr浆状催化剂二甲醚合成宏观动力学%Global kinetics of direct synthesis of dimethyl ether from syngas in slurry reactor over Cu-Zn-Al-Zr catalyst

    Institute of Scientific and Technical Information of China (English)

    陈振; 张海涛; 应卫勇; 房鼎业

    2011-01-01

    在压力3MPa~7MPa,温度220℃~260℃,空速0.4 L·g-1·h-1~1.2 L·g1·h-1,气体摩尔分率yH2 0.75~0.65,y∞ 0.14~0.20,y(00)2 0.04~0.08,搅拌转速1000 r·min-1的反应条件下,于500mL高压搅拌釜中进行了合成气在Cu-Zn-Al-Zr浆状催化剂上一步法合成二甲醚工艺过程的宏观动力学研究.基于CO加氢合成甲醇、CO2加氢合成甲醇及甲醇脱水为二甲醚三个独立反应,建立了Langmuir-Hinshelwood型宏观动力学模型.采用通用遗传算法和Levenberg-Marquardt优化算法相结合的方法对实验数据进行拟合、参数寻优,获得模型参数估值,经统计检验和残差分析证实了模型的可靠性.%The global kinetics of the slurry synthesis of dimethyl ether from syngas in a stirred autoclave over Cu-Zn-Al-Zr catalyst was studied at pressure of 3-7MPa, temperature of 220-260'C, WHSV of 0.4-1.2 L-g'-h"1 and mole fractions of H2, CO and CO2 in feed gas of 0.75-0.65, 0.14-0.20 and 0.04-0.08, respectively. Three reactions, CO hydrogenation to methanol, C02 hydrogenation to methanol and methanol dehydration to dimethyl ether, were chosen as the independent reactions and based on that a Langmuir-Hinshelwood type global kinetic model was built. The model parameters were estimated by fitting experimental data and parameter optimization based on general Genetic Algorithm and Levenberg- Marquardt methods, and the reliability of model was verified by statistical test and residual error analysis.

  7. Hybrid adsorptive membrane reactor

    Science.gov (United States)

    Tsotsis, Theodore T. (Inventor); Sahimi, Muhammad (Inventor); Fayyaz-Najafi, Babak (Inventor); Harale, Aadesh (Inventor); Park, Byoung-Gi (Inventor); Liu, Paul K. T. (Inventor)

    2011-01-01

    A hybrid adsorbent-membrane reactor in which the chemical reaction, membrane separation, and product adsorption are coupled. Also disclosed are a dual-reactor apparatus and a process using the reactor or the apparatus.

  8. D and DR Reactors

    Data.gov (United States)

    Federal Laboratory Consortium — The world's second full-scale nuclear reactor was the D Reactor at Hanford which was built in the early 1940's and went operational in December of 1944.D Reactor ran...

  9. Hybrid adsorptive membrane reactor

    Science.gov (United States)

    Tsotsis, Theodore T.; Sahimi, Muhammad; Fayyaz-Najafi, Babak; Harale, Aadesh; Park, Byoung-Gi; Liu, Paul K. T.

    2011-03-01

    A hybrid adsorbent-membrane reactor in which the chemical reaction, membrane separation, and product adsorption are coupled. Also disclosed are a dual-reactor apparatus and a process using the reactor or the apparatus.

  10. Reaction Engineering with Metal-Organic Framework Catalysts

    Science.gov (United States)

    Melkonian, Arek Viken

    To date, there has been no comprehensive attempt to perform and/or describe catalytic reactions in the gas phase that utilize metal-organic frameworks (MOFs) as catalysts. In addition, there has been no attempt to reaction engineer these MOF catalysts in order to determine their regimes of optimal catalytic activity and possible limitations to their use. A zinc-based MOF that has been post-synthetically modified with a homogeneous palladium catalyst, Pd(CH 3CN)2Cl2, is used to catalyze the hydrogenation of propylene. The catalyst is assembled in a packed-bed reactor under a continuous flow of reactants. The reaction is optimized with respect to isoreticular metalation, reactant flow rate, and reactor temperature. Maximum catalytic conversion is found at intermediate metalations of 40% and 60%, high hydrogen flow of 50 ccm, and intermediate reactor temperatures of 100 °C and 150 °C. The MOF-60 catalyst is exposed to a traditional catalyst poison, carbon monoxide (CO). It is found that the MOF is reversibly poisoned upon introduction of CO. Upon poisoning, catalytic conversions rates of 90%-100% are dramatically reduced to less than 10%-30%, depending on the CO flow rate and the reactor temperature. The CO poisoning is shown to be reversible, a similar effect as found with palladium on carbon (Pd/C). The time scale of poisoning and recovery is very fast for both the MOF catalyst and Pd/C (approximately 10-30 seconds). Other effects of temperature on the MOF-40 are also investigated. At fixed reactant flow, the temperature grid is partitioned into finer steps of 10 °C to determine the temperature that yields the highest catalytic conversion. It is found that conversion is nearly uniform in the range between the highest conversions, i.e., conversion plateaus between the optimum temperatures. The catalyst also exhibits a weak thermal hysteresis. There is no significant improvement in conversion with thermal cycling after alternating the reactor temperature between

  11. Carbon nanotube patterning with capillary micromolding of catalyst.

    Science.gov (United States)

    Lee, Jaewon; Ryu, Choonghan; Lee, Sungwoo; Jung, Donggeun; Kim, Hyoungsub; Chae, Heeyeop

    2007-11-01

    Patterning of multi-walled carbon nanotube (MWNT) in a plasma enhanced chemical vapor deposition (PECVD) chamber has been achieved by catalyst patterning using capillary micromolding process. Iron acetate catalyst nanoparticles were dissolved in ethanol and mold was fabricated with polydimethylsiloxane (PDMS). The ethanol solution containing catalyst nanoparticles was filled into the microchannel formed between PDMS mold and Si-wafer by capillary force. The capillary action of different solvents was simulated by commercial CFD-ACE+ simulation code to determine optimal solvents. Simulated result shows that the choice of solvent was critical in this capillary filling process. After the catalyst patterning, MWNT was grown at 700 approximately 800 degrees C by PECVD process using CH4 and Ar gas in a scale of approximately 10 micro-meters in a tubular inductively coupled plasma reactor. Grown CNTs were analyzed by FE-SEM and Raman Spectroscopy.

  12. A novel reverse flow reactor coupling endothermic and exothermic reactions: an experimental study

    NARCIS (Netherlands)

    van Sint Annaland, M.; Nijssen, R.C.

    2002-01-01

    A new reactor concept is studied for highly endothermic heterogeneously catalysed gas phase reactions at high temperatures with rapid but reversible catalyst deactivation. The reactor concept aims to achieve an indirect coupling of energy necessary for endothermic reactions and energy released by

  13. Performance characteristics between monolithic and microservice-based systems

    OpenAIRE

    Flygare, Robin; Holmqvist, Anthon

    2017-01-01

    A new promising technology to face the problem of scalability and availability is the microservice architecture. The problem with this architecture is that there is no significant study that clearly proves the performance differences compared to the monolithic architecture. Our thesis aims to provide a more conclusive answer of how the microservice architecture differs performance wise compared to the monolithic architecture. In this study, we conducted several experiments on a self-developed...

  14. Sol-Gel Synthesis of Non-Silica Monolithic Materials

    Directory of Open Access Journals (Sweden)

    Bartłomiej Gaweł

    2010-04-01

    Full Text Available Monolithic materials have become very popular because of various applications, especially within chromatography and catalysis. Large surface areas and multimodal porosities are great advantages for these applications. New sol-gel preparation methods utilizing phase separation or nanocasting have opened the possibility for preparing materials of other oxides than silica. In this review, we present different synthesis methods for inorganic, non-silica monolithic materials. Some examples of application of the materials are also included.

  15. Reliability Analysis and Optimal Design of Monolithic Vertical Wall Breakwaters

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Burcharth, Hans F.; Christiani, E.

    1994-01-01

    Reliability analysis and reliability-based design of monolithic vertical wall breakwaters are considered. Probabilistic models of the most important failure modes, sliding failure, failure of the foundation and overturning failure are described . Relevant design variables are identified and relia......Reliability analysis and reliability-based design of monolithic vertical wall breakwaters are considered. Probabilistic models of the most important failure modes, sliding failure, failure of the foundation and overturning failure are described . Relevant design variables are identified...

  16. Extended Leach Testing of Simulated LAW Cast Stone Monoliths

    Energy Technology Data Exchange (ETDEWEB)

    Serne, R. Jeffrey [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Westsik, Joseph H. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Williams, Benjamin D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Jung, H. B. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Wang, Guohui [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2015-07-09

    This report describes the results from long-term laboratory leach tests performed at Pacific Northwest National Laboratory (PNNL) for Washington River Protection Solutions (WRPS) to evaluate the release of key constituents from monoliths of Cast Stone prepared with four simulated low-activity waste (LAW) liquid waste streams. Specific objectives of the Cast Stone long-term leach tests described in this report focused on four activities: 1. Extending the leaching times for selected ongoing EPA-1315 tests on monoliths made with LAW simulants beyond the conventional 63-day time period up to 609 days reported herein (with some tests continuing that will be documented later) in an effort to evaluate long-term leaching properties of Cast Stone to support future performance assessment activities. 2. Starting new EPA-1315 leach tests on archived Cast Stone monoliths made with four LAW simulants using two leachants (deionized water [DIW] and simulated Hanford Integrated Disposal Facility (IDF) Site vadose zone pore water [VZP]). 3. Evaluating the impacts of varying the iodide loading (starting iodide concentrations) in one LAW simulant (7.8 M Na Hanford Tank Waste Operations Simulator (HTWOS) Average) by manufacturing new Cast Stone monoliths and repeating the EPA-1315 leach tests using DIW and the VZP leachants. 4. Evaluating the impacts of using a non-pertechnetate form of Tc that is present in some Hanford tanks. In this activity one LAW simulant (7.8 M Na HTWOS Average) was spiked with a Tc(I)-tricarbonyl gluconate species and then solidified into Cast Stone monoliths. Cured monoliths were leached using the EPA-1315 leach protocol with DIW and VZP. The leach results for the Tc-Gluconate Cast Stone monoliths were compared to Cast Stone monoliths pertechnetate.

  17. OXIDATIVE COUPLING OF METHANE USING INORGANIC MEMBRANE REACTORS

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Y.H. Ma; Dr. W.R. Moser; Dr. A.G. Dixon; Dr. A.M. Ramachandra; Dr. Y. Lu; C. Binkerd

    1998-04-01

    The objective of this research is to study the oxidative coupling of methane in catalytic inorganic membrane reactors. A specific target is to achieve conversion of methane to C{sub 2} hydrocarbons at very high selectivity and higher yields than in conventional non-porous, co-feed, fixed bed reactors by controlling the oxygen supply through the membrane. A membrane reactor has the advantage of precisely controlling the rate of delivery of oxygen to the catalyst. This facility permits balancing the rate of oxidation and reduction of the catalyst. In addition, membrane reactors minimize the concentration of gas phase oxygen thus reducing non selective gas phase reactions, which are believed to be a main route for the formation of CO{sub x} products. Such gas phase reactions are a cause of decreased selectivity in the oxidative coupling of methane in conventional flow reactors. Membrane reactors could also produce higher product yields by providing better distribution of the reactant gases over the catalyst than the conventional plug flow reactors. Membrane reactor technology also offers the potential for modifying the membranes both to improve catalytic properties as well as to regulate the rate of the permeation/diffusion of reactants through the membrane to minimize by-product generation. Other benefits also exist with membrane reactors, such as the mitigation of thermal hot-spots for highly exothermic reactions such as the oxidative coupling of methane. The application of catalytically active inorganic membranes has potential for drastically increasing the yield of reactions which are currently limited by either thermodynamic equilibria, product inhibition, or kinetic selectivity.

  18. Catalyst Deactivation: Control Relevance of Model Assumptions

    Directory of Open Access Journals (Sweden)

    Bernt Lie

    2000-10-01

    Full Text Available Two principles for describing catalyst deactivation are discussed, one based on the deactivation mechanism, the other based on the activity and catalyst age distribution. When the model is based upon activity decay, it is common to use a mean activity developed from the steady-state residence time distribution. We compare control-relevant properties of such an approach with those of a model based upon the deactivation mechanism. Using a continuous stirred tank reactor as an example, we show that the mechanistic approach and the population balance approach lead to identical models. However, common additional assumptions used for activity-based models lead to model properties that may deviate considerably from the correct one.

  19. Robust CoAl Alloy: Highly Active, Reusable and Green Catalyst in the Hydrogenolysis of Glycerol%Robust CoAl Alloy: Highly Active, Reusable and Green Catalyst in the Hydrogenolysis of Glycerol

    Institute of Scientific and Technical Information of China (English)

    郭晓洋; 尹安远; 郭晓东; 郭秀英; 戴维林; 范康年

    2011-01-01

    CoAl alloy catalyst is found, for the first time, to be highly active, selective and reusable for the synthesis of diols via the hydrogenolysis of glycerol under mild conditions. The products and the catalyst could be self-separated from the reaction system through a simple reactor.

  20. Novel Solar Photocatalytic Reactor for Wastewater Treatment

    Science.gov (United States)

    Sutisna; Rokhmat, M.; Wibowo, E.; Murniati, R.; Khairurrijal; Abdullah, M.

    2017-07-01

    A new solar photocatalytic reactor (photoreactor) using TiO2 nanoparticles coated onto plastic granules has been designed. Catalyst granules are placed into the cavity of a reactor panel made of glass. A pump is used to circulate wastewater in the photoreactor. Methylene blue (MB) dissolved in water was chosen as the wastewater model. The performance of the photoreactor was evaluated based on changes in MB concentration with respect to time. The photoreactor showed a good performance by degrading 10 L of MB solution up to 96.54% after 48 h of solar irradiation. The photoreactor was scaled up by enlarging the panel area to twice its original size. The increase in the surface area of the reactor panel and therefore of the mass of catalyst granules and reactor volume led to a three-fold increase of the photodegradation rate. In addition, the MB degradation kinetics were also studied. Data analysis confirmed the applicability of the pseudo-first-order Langmuir-Hinshelwood model. The proposed photoreactor has great potential for use in large-scale wastewater treatment.