Science.gov (United States)

The oxidative dehydrogenation (OXDH) of n-butane, 1-butene, and trans-2-butene on different vanadia catalysts has been compared. MgO, alumina, and Mg-Al mixed oxides with Mg/(Al + Mg) ratios of 0.25 and 0.75 were used as supports. The catalytic data indicate that the higher the acid character of catalysts the lower is both the selectivity to C{sub 4}-olefins from n-butane and the selectivity to butadiene from both 1-butene or trans-2-butene. Thus, OXDH reactions are mainly observed from n-butane and butenes on basic catalysts. The different catalytic performance of both types of catalysts is a consequence of the isomerization of olefins on acid sites, which appears to be a competitive reaction with the selective way, i.e., the oxydehydrogenation process by a redox mechanism. Infrared spectroscopy data of 1-butene adsorbed on supported vanadium oxide catalysts ...

Science.gov (United States)

A method for analyzing the experimental results of coal liquefaction reactions which is applicable to a number of aspects of coal liquefaction research and process control, including rapid selectivity and performance screening for catalysts; correlation of laboratory results with process parameters; and optimization of product yield with plant process conditions is described here. Ternary diagrams of product/by-product distributions for the coal liquefaction using Co/Mo catalysts combined with a hyperbolic relationship for the conversion of various hydrocarbon fractions can be used for catalyst screening. A hydrogen consumption diagram used to provide a more significant selectivity test than the hyperbolic correlation is also included. (BLM)

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The fixed bed pilot plant, the catalyst testing procedure, and the calculations for conversion and selectivities were previously described in the technical progress report covering the period of 3/16/88 to 6/16/88 for Contract DE-AC22-87PC79812. Conversions and hydrocarbon selectivities were calculated using data from an on-line gas chromatography (GC) analyzer. Alcohol selectivities were calculated using data from an on-line boiling point GC analyzer which analyzed the liquid product. The catalysts were prepared via the steps of impregnation, calcination, and reduction on a special Y-zeolite-derived support. The impregnation step consisted of evaporation of metal salts on to the support from an aqueous solution. For one catalyst (No. 6531-188) the metal salts were evaporated on to the support from a reverse micelle solution containing the metal salts. All the ...

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The purpose of this study is to prevent the deactivation of catalysts recycled in the 0.1 t/d bench scale unit (BSU). Catalysts recovered during reactions in the BSU and after reactions in the 5-liter autoclave were analyzed, to investigate the influences of the reaction condition on the property and activity of catalysts. Were used {gamma}-iron oxyhydroxide ({gamma}-FeOOH), {alpha}-iron oxyhydroxide ({alpha}-FeOOH), and natural pyrite (FeS2) as catalysts. At the S/Fe atomic ration of 1.2 under the BSU reaction condition, troilite was more easily formed from {gamma}-FeOOH compared with pyrite and {alpha}-FeOOH. As the reaction proceeded through the first, second, and third reactors, the crystal size increased, the pyrrhotite content decreased, and the troilite content increased. Deactivation due to the formation of troilite was irreversible. At the S/Fe of 3.0, however, both the ...

Scientific Electronic Library Online (English)

Abstract in english Higher olefins are produced as a by product in a number of refinery processes and are one of the potential raw materials to produce propylene. In the present study, FCC model feed compound was considered to explore the olefin cracking features and options to enhance propylene using 30% SAPO-34 zeolite as catalyst in a micro-reactor. The superior selectivity of propylene (73 wt%) and higher total olefin selectivity was obtained over 30% SAPO-34 catalyst than over Y or ZSM- (more) 5 zeolite catalysts. The thermodynamical constraints were found to be relatively less serious in the case of 1-hexene conversion. Most of the 1-hexene follows a direct cracking pathway to give two propylene molecules, due to weak acid sites and better diffusion opportunities. The higher temperature and short residence time could also suppress the hydrogen transfer reactions. From OPE (olefins performance envelop) the products ...

British Library Electronic Table of Contents (United Kingdom)

The author analyzes conference materials, emphasizing the studies and latest developments useful for industrial heterogeneous catalysis in view of the requirements of green chemistry. Industrial catalysts is developing along a nanometer scale, so especial attention is devoted to analyzing the reports in the Nanochemistry section on the creation of nanocatalysts, the production of active phase nanoparticles, and the formation of new synthesized material properties. The catalysts developed earlier by Russian research in cooperation with Belarusian scientists are considered, and it is shown that not only are expensive nanocontacts extremely promising for industry, but the efficient and economic low-percentage new generation of nanocatalysts synthesized by wet chemistry and containing nanopart...

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Very high cobalt catalysts have been prepared on steamed and acid-washed y zeolite. These catalysts are very active. Some of them have proven to be very stable. Additionally, if provisions are made to control the temperature build up on the catalyst bed, low methane selectivities result. Additional work is indicated, for instance, perhaps even higher activity catalysts can result from higher levels of cobalt or changes in the catalyst preparation procedure. Since the issue of whether small amounts of ruthenium can promote the catalyst is not completely resolved, catalyst preparation procedure experiments should continue with ruthenium vs. ruthenium-free catalysts. For instance, different methods of impregnation and/or activation should be investigated.

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A phosphorus-containing low alkali metal content zeolitic catalyst made from a clay starting material is provided. The catalyst is obtained by contacting a partially cation exchanged calcined zeolite-containing catalyst with an anion such as a dihydrogen phosphate anion or a dihydrogen phosphite anion and additionally with an ammonium salt other than a salt of an inorganic acid of phosphorus. A hydrocarbon catalytic cracking process utilizing the phosphorus-containing catalyst is also provided.

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In order to replace industrial cobalt and nickel and molybdenum catalysts, more economical catalysts, red muds, are used. Comparative data about the chemical, structural and thermal properties of different samples of red muds, which are important for catalytic hydrogenation, are cited. The different conditions for hydrogenation of coals in a reactor are examined.

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This patent describes a catalyst composition. It consists of the catalytic oxides of iron, bismuth, molybdenum and magnesium as essential components and optionally the oxides of cobalt, nickel, phosphorus and arsenic.

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Short communication.

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Red mud is a by-product of bauxite processing through Bayer process. The amount of red mud generated depends largely on the type of ore used and the processing. Use of red mud as a catalyst can be a good alternative to the existing commercial catalysts. Its properties such as iron content in form of ferric oxide (Fe{sub 2}O{sub 3}), high surface area, sintering resistance, resistance to poisoning and low cost make it an attractive potential catalyst for many reactions. Besides red mud, ferric ion sludge from wastewater treatment plant has also been studied for its catalytic properties, mainly due to its ferric oxide constituent. This paper reviews the studies on red mud as a catalyst. The catalyst characteristics, reaction mechanisms involved and performance are examined and compared with iron oxide catalyst and commercial catalysts. ...

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Energy from biomass is a CO{sub 2} neutral, sustainable form of energy. Anaerobic digestion is an established technology for converting biomass to biogas, which contains around 60% methane, besides CO{sub 2} and various contaminants. Most types of biomass contain material that cannot be digested; in woody biomass, this portion is particularly high. Therefore, conventional anaerobic digestion is not suited for the production of biogas from woody biomass. While wood is already being converted to energy by conventional thermal methods (gasification with subsequent methanation), dung, manure, and sewage sludge represent types of biomass whose energy potential remains largely untapped (present energetic use of manure in Switzerland: 0.4%). Conventional gas phase processes suffer from a low efficiency due to the high water content of the feed (enthalpy of vaporization). An alternative technology is the hydrothermal gasification: the water contained within the biomass serves as reaction ...

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It has been discovered that when Taiheiyo coal pulverized to 200 mesh or smaller is dispersed in naphthalene, a non-hydrogen-donor solvent, and reacted under hydrogen pressure in the presence of a red mud/sulfur catalyst, the catalyst exhibits activity in the regeneration of hydrogen donor solvents which have been hydrogen-depleted in the course of coal liquefaction. It is already known that inorganic matter contained in coal acts as a catalyst in liquefaction. This suggests that the reported effect of the red mud/sulfur catalyst is due to the iron oxide reacting with the sulfur and forming pyrrhotite. 22 refs., 6 figs., 1 tab.

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The objective of this 3.5 year project is to develop a commercially competitive vehicle powered by ethanol (or ethanol blend) that can meet California`s ultra-low emission vehicle (ULEV) standards and equivalent corporate average fuel economy (CAFE) energy efficiency for a light-duty passenger car application. The definition of commercially competitive is independent of fuel cost, but does include technical requirements for competitive power, performance, refueling times, vehicle range, driveability, fuel handling safety, and overall emissions performance. This report summarizes a system design study completed after six months of effort on this project. The design study resulted in recommendations for ethanol-fuel blends that shall be tested for engine low-temperature cold-start performance and other criteria. The study also describes three changes to the engine, and two other changes to the vehicle to improve low-temperature starting, efficiency, and emissions. The three engine ...

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A thermal analyzer-differential scanning calorimeter-mass spectrometer (TG-DSC-MS) was used to study oxygen carriers (OC) for their potential use for the application of chemical looping combustion (CLC) to solid fuels. Reaction rates, changes in reaction rates with repeated oxidation-reductions, exothermic heats during oxidation, and the effect of changing reduction gas compositions were studied. Oxidation rates were greater than reduction rates and reaction rates were reproducible through multiple oxidation-reduction cycles except where agglomeration occurred with powders. Iron oxide (Fe{sub 2}O{sub 3} powder) and iron-based catalysts were found suitable for CLC of solid fuels having rapid reduction rates which increased with higher reducing gas concentrations. Fe{sub 2}O{sub 3} powder was used to oxidize a high carbon coal char in an inert gas removing 88% of the carbon from the char. Other properties such as cost and durability indicated ...

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The indirect conversion of coal to liquid hydrocarbons via steam gasification followed by synthesis gas (CO/H/sub 2/) chemistry has been the subject of intensive study for a number of decades. A key technological challenge facing researchers in this area is control over the product distribution during the hydrocarbon synthesis step. In the case of iron Fischer-Tropsch catalysts, it has been known that the addition of alkali to the metal catalyst has a significant impact on the product distribution. Iron catalysts treated with alkali produce less methane more alkenes and higher molecular weight products. In spite of numerous investigations, the details of this promotional effect are not understood on a molecular level. To explore the role of alkali in the surface chemistry of iron catalysts, the authors have carried out a combined surface science and catalytic kinetic study of a model iron ...

British Library Electronic Table of Contents (United Kingdom)

Co catalysts, obtained from a layered double Co?Zn?Al hydroxide, are highly active and stable towards the hydrogenolysis of glycerol to 1,2-propanediol (1,2-PDO) in aqueous media. The Co-673 catalyst, containing a CoO species, provided a glycerol conversion of 67.7% and a 1,2-PDO selectivity of 50.5%. The Co-873 catalyst comprising 16?nm Co nanoparticles gave a glycerol conversion of 70.6% and a 1,2-PDO selectivity of 57.8%. It was revealed that the CoO species in the Co-673 catalyst was readily converted to 50?nm Co particles under the glycerol hydrogenolysis conditions. The Co catalysts maintained a stable size and phase in recycling tests. Graphical Abstract

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In the dehydrodesulfurization of ethanethiol at 400/sup 0/C, the activities of sodium X, Y, and A zeolites decreased in the order given as did the activities of nickel, cobalt, zinc, cadmium, copper, silver, lead, manganese, barium, calcium, sodium, and iron Y zeolite catalysts. A volcano-shape order was observed between the catalytic activity and the electronegativity of the metal ions. The changes in the activity of hydrogen Y zeolite catalyst in ethanethiol dehydrodesulfurization and cumene dealkylation by calcination agreed with the decrease in the Broensted acidity but were independent of Lewis acidity. For hydrodesulfurization of thiophene, the activities of nickel, cobalt, copper, and silver Y zeolite catalysts decreased in the order given and were greater than for a commercial hydrodesulfurization catalyst; reduced and presulfided catalysts showed selective ...

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Y-zeolite supported catalysts were applied to the hydrocracking of coal-derived liquids. By the introduction of two-stage upgrading consisting of hydrotreating and hydrocracking, Wandoan coal-derived middle distillate was hydrocracked over Ni-Mo/Y-zeolite, producing a high gasoline fraction yield. Zeolite supported catalysts gave little hydrocracked compounds in the hydroprocessing of coal-derived heavy oils, even after hydrotreatment. The reaction inhibitors which seriously poison the active sites of zeolites were found to be small nitrogen-containing molecules. In the hydroprocessing of coal-derived heavy oils, zeolite supported catalysts were inferior to alumina supported catalysts. This is due to the high hydrocracking but low hydrogenation activity of zeolite supported catalysts. 22 refs., 5 figs., 11 tabs.

Energy Technology Data Exchange (ETDEWEB)

This work studied the effect of the nature of the metal on the performance of Co/CeO{sub 2}, Pd/CeO{sub 2} and Pt/CeO{sub 2} catalysts in the partial oxidation of ethanol. Infrared spectroscopy of adsorbed ethanol and temperature programmed desorption of ethanol were performed in order to establish the reaction mechanism. Catalytic experiments revealed that the product distribution is strongly affected by the nature of the metal. Acetaldehyde was practically the only product formed on a Co/CeO{sub 2} catalyst while methane was also produced on Pt/CeO{sub 2} and Pd/CeO{sub 2} catalysts. These results were explained through a reaction mechanism proposed by the characterization techniques. Co/CeO{sub 2} and Pt/CeO{sub 2} catalysts show mainly ethoxy species at room temperature whereas acetate species is mainly formed on the Pd/CeO{sub 2} catalyst. The ethoxy species can undergo further ...

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The authors investigate the possibility of the direct heterogeneous catalytic synthesis of ethylbenzoate from benzonitrile. The catalysts tested were oxides of aluminium, titanium, and vanadium. The main conversion product detected chromatographically was ethylbenzoate; benzaldehyde, benzamide, and benzanilide were also identified. Aluminium oxide was found to be the most effective catalyst.

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The abstracts of all the presentations (1 plenary session, 2 keynotes, 52 oral communications, 496 posters) of the thematic session 1: 'catalyst preparation and characterization' are gathered in the CD-Rom of the conference. The main application described concerns the petroleum industry. (O.M.)

Science.gov (United States)

Pd-Ag bimetallic catalysts, supported on gamma-Al2O3, have been evaluated as exhaust catalysts for methanol-fueled vehicles. Laboratory studies have shown that a 0.01% Pd-5% Ag catalyst has greater CO and CH3OH oxidation activity than either 0.01% Pd or 5% Ag catalysts alone. Moreover, Pd and Ag interact synergistically in the bimetallic catalyst to produce greater CO and CH3OH oxidation rates and lower yields of methanol partial oxidation products than expected from a mixture of the single-component catalysts. The Pd-Ag synergism results from Pd promoting the rate of O2 adsorption and reaction with CO and CH3OH on Ag. Rate enhancement by the bimetallic catalyst is greatest at short reactor residence times where the oxygen adsorption rate limits the overall reaction rate.

J-STORE (Japan)

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Promoted antimony phosphate oxide complexes are excellent catalysts for the ammoxidation of methanol to HCN especially at high methanol throughputs.

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The catalytic properties of molybdena-alumina catalysts reduced in hydrogen were studied in the function of the reduction temperature, i.e. in the function of the extent of reduction. The deuterium exchange reaction of benzene was used as model catalytic reaction. It was concluded that the reaction rate constant and the multiplicity factor decreased with the extent of reduction parallel with the change in the extent of dehydroxylation of the catalysts. (orig.)

Science.gov (United States)

Platinum and ruthenium in carbon supported Pt and Pt-Ru catalysts were determined by direct and derivative spectrophotometric methods. Complexes of platinum and ruthenium with SnCl(3)(-) ligands (tin(II) chloride in HCl) were used to determine both metals in solutions obtained after digestion of the samples of the catalysts. Platinum in the Pt/C catalyst can be determined in solutions obtained by digestion of the samples in aqua regia. Derivative spectrophotometry was used to determine both metals in the presence of each other in solutions obtained after digestion of samples of the Pt-Ru/C catalyst in the mixture of HCl+HNO(3) (6:1). The first derivative at 377 nm (;zero-crossing' point of ruthenium) and the second-derivative values at 495 nm (;zero-crossing' point of platinum) were used to estimate the concentration of platinum and ruthenium, respectively. PMID:18967441

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Rye straw was completely hydroliquefied, using red mud or CoO-MoO{sub 3} as the catalyst. Red mud catalyst exhibited a satisfactory activity only in the presence of sulphur at {approx} 673 K. Depending on reaction conditions, different amounts of gaseous and liquid products were formed. Their product distributions were comparable to those obtained in hydroliquefaction of cellulose and lignin. All results could be described by a model which assumed that: pyrolysis precedes hydrogenation of pyrolysis products; CO and CO{sub 2} are products of pyrolysis reaction; and hydrogen is consumed mainly in hydrodeoxygenation reactions. Therefore, from a practical point of view, red mud, which is known as a coal liquefaction catalyst, can also be recommended as a cheap and powerful catalyst in the hydroliquefaction of biomass. 29 refs., 6 figs., 11 tabs.

Energy Technology Data Exchange (ETDEWEB)

The vast majority of fundamental studies of metal oxide selective oxidation catalysts have been performed with single phase systems. These investigations established the basic tenents of the redox mechanism of selective oxidation and ammoxidation catalysis. By comparison, structural and kinetic investigations of multiphase oxide catalysts are less numerous because of the inherent difficulties in understanding the relative contributions of separate phases to the catalytic behavior of the composite catalyst. Some attempts have been made in the past to understand the complex chemistry of multiphase catalysts and additional important insights have been realized more recently. However, a clear understanding of the most significant catalytic interactions between individual phases of a multiphase multicomponent redox catalyst is still lacking. In an effort to provide an understanding and a ...

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The aim of this work is to test the catalytic oxidation of pyridine over zeolite-supported catalysts and to compare the difference in their activities for the oxidation of pyridine. The catalytic oxidation of pyridine pollutant on a series of copper-supported catalysts, inclusive of Cu/beta, Cu/ZSM-5, Cu/MCM-41 and Cu/{gamma}-Al{sub 2}O{sub 3}, in the presence of excess oxygen was studied. The activity of the copper-supported catalysts for the pyridine oxidation could be correlated with the binding energy of oxygen coordinated to metal copper, while the ability to control the yield of NO{sub x} appeared to be strongly dependent on the binding energy of NO bonded to metal copper. On these catalysts, two copper species, Cu(H{sub 2}O){sub 6}{sup 2+} ions and CuO were identified, in which Cu{sup 2+} ions had higher activity for the NO{sub x} control but poorer activity for the pyridine oxidation. Amongst ...

Energy Technology Data Exchange (ETDEWEB)

Influence of residual K{sup +} on the preferential oxidation of CO in excess hydrogen (PROX) over CuO-CeO{sub 2} catalysts was investigated. CuO-CeO{sub 2} catalysts were characterized by BET, ICP, XRD, UV-Raman and TPR techniques. The results showed that the existence of residual K{sup +} made {alpha} peak in TPR of CuO-CeO{sub 2} catalysts shift to higher temperatures and depressed the PROX in the absence of CO{sub 2} and H{sub 2}O in the feed over CuO-CeO{sub 2} catalysts. However, small amount of residual K{sup +} was beneficial to the catalytic performance of CuO-CeO{sub 2} catalysts in the PROX in the presence of CO{sub 2} and H{sub 2}O in the feed. Consequently, residual K{sup +} with an appropriate content was beneficial to improve the catalytic performance of CuO-CeO{sub 2} catalysts in the presence of CO{sub 2} and H{sub 2}O. (author)

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Performance of various catalysts for hydrogenation of recycle solvent was evaluated for the operation of NEDOL process 1 t/d process supporting unit (PSU). Distillate between 220 and 538{degree}C derived from the liquefaction of Tanito Harum coal was used as recycle solvent. Deactivation behaviors of catalysts were compared using a prediction equation of catalyst life, by which aromatic carbon index (fa) after hydrogenation can be determined from the fa of recycle oil before hydrogenation, reaction temperature, and total hydrogenation time. Total hydrogenation time satisfying the {Delta}fa, 0.05 before and after hydrogenation were 8,000, 4,000, and 2,000 hours for NiMo-based catalysts C, A, and B, respectively. Catalyst C showed the longest life. Used catalysts were also characterized. The catalyst C showed larger mean pore size than those ...

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The paper discusses two petrochemical selective oxidation reactions namely the practised formation of styrene (STY) and the desired oxidative functionalisation of propane. The present knowledge about the mode of operation of oxide catalysts is critically considered. The dehydrogenation of ethylbenzene (EB) should be described by an oxidehydration with water acting as oxidant. The potential role of the coke formed during catalytic reaction as co-catalyst will be discussed. Selective oxidation is connected with the participation of lattice oxygen mechanism which transforms unselective gas phase oxygen into selective oxygen. The atomistic description of this process is still quite unclear as well as the electron structural properties of the activated oxygen atom. The Role of solid state acidity as compared to the role of lattice oxygen is much less well investigated modern multiphase-multielement oxide (MMO) catalysts. The ...

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Chloromethane, dichloromethane and 1,2-dichloroethane were completely decomposed in air on perovskite-type catalysts (LaMnO{sub 3}, LaCoO{sub 3}, (La{sub 0.84},Sr{sub 0.16})(Mn{sub 0.67},Co{sub 0.33})O{sub 3}) at reaction temperatures above 550C. Besides the main reaction products (carbon dioxide, water and hydrochloric acid), by-products (higher chlorinated-, C-C coupling- and cracking products) were formed in the low temperature range. Depending on the reaction temperature, residence time and kind of chlorinated hydrocarbon a reversible catalyst deactivation takes place. In the case of LaCoO{sub 3} catalysts an irreversible deactivation was observed. X-ray diffraction (XRD) and electron probe microanalysis (EPMA) measurements with the perovskite-type catalysts after interaction of chlorinated hydrocarbons indicate the formation of chlorinated species on the catalyst surface and in ...

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The oxidative dehydrodimerization of propylene to C/sub 3/-dimers (1,5-hexadiene and benzene) has been examined at 600/sup 0/C and atmospheric pressure using a (Bi/sub 2/O/sub 3/)/sub 0.85/(La/sub 2/O/sub 3/)/sub 0.15/ oxide ion-conducting catalyst in a reactor where a catalyst disk separates a feed of propylene in helium from air. The surface of the disk exposed to propylene was reoxidized not by gaseous O/sub 2/, but by the dissociative adsorption and reduction of dioxygen at the oxidant side of the disk, followed by oxide ion conduction to replace spent lattice oxygen. Selectivity to C/sub 3/-dimers when using lattice oxide migration to reoxidize the catalyst was considerably greater than when O/sub 2/ was added to the propylene feed under the same reaction conditions. This result supports the proposal that lattice oxygen is predominantly involved in the selective oxidation of propylene to C/sub 3/-dimers, and ...

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The NiMo sulfide supported on Ketjen Black (KB) was more effective and yielded lighter oil products containing light fractions with their boiling point below 300{degree}C during the two stage liquefaction combining low temperature and high temperature hydrogenation the conventional NiMo/alumina catalyst and FeS2 catalyst. Although the NiMo/alumina yielded increased oil products during the two stage liquefaction, the lighter oil fractions did not increase and the heavier fractions increased mainly. This suggests that the hydrogenation of aromatic rings and successive cleavage of the rings are necessary for producing the light oil, which is derived from the sufficient hydrogenation of aromatic rings using catalysts. For the two stage reaction with NiMo/KB catalyst, it was considered that sufficient hydrogen was directly transferred to coal molecules at the first stage of the low temperature reaction, ...

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Special CoMo/Al{sub 2}O{sub 3} catalysts were prepared for testing in coal liquefaction: a conventional CoMo/Al{sub 2}O{sub 3} catalyst, one containing Zn as a second promoter and one having the alumina acidified with fluorine. Their activities were compared with that of red mud. The experiments were conducted in a stirred autoclave with a subbituminous coal and solvent (tetralin, anthracene oil or creosote oil) at 425{degree}C and 17 MPa. The liquefaction products were fractionated into oils, asphaltenes and preasphaltenes with pentane, toluene and THF. The Co(Zn)Mo/Al{sub 2}O{sub 3} catalysts have far higher activities than red mud. Zn and fluorine have beneficial effects on the catalyst activity. Coal tar distillates give higher conversions and oil + gas yields than tetralin when the prepared catalysts are used. 17 refs., 7 tabs.

Energy Technology Data Exchange (ETDEWEB)

This quarterly report for the period April through June 1984 summarizes activities in Sandia National Laboratories' continuing program of coal liquefaction research. The primary goals are to: explore novel catalytic concepts and materials for conversion of coal to liquid fuels; determine the effects of process variables on catalyst deactivation; determine the effects of coal structure and solvent properties on low temperature dissolution; study the kinetics and catalysis of hydrogen transfer reactions; develop an understanding of slurry gelling phenomena; and provide a technical assessment of coal liquefaction processes. During this period, work was performed on: analysis of catalyst samples from Wilsonville Run 246; catalyst presulfiding; catalyst activity testing using pyrene as a chemical probe; catalyst deactivation using a high-pressure model compound test reactor; ...

Science.gov (United States)

Grassroots education is imperative if economic development is to be actualized. Therefore, it becomes necessary to study the primary school teachers' perception of the Universal Basic Education (UBE). This study attempted to find out the primary school teachers' perception of the Universal Basic Education (UBE) programme and their perceived contribution towards the success of the programme. It further examined how favorable perception towards the scheme could be a catalyst in the successful implementation of the UBE. To accomplish this task, two research questions and a hypothesis were raised to guide the study. The opinion of one hundred and eighteen (118) teachers, out of four hundred and forty-seven teachers (447) that constituted the population of the teachers in Esan West Public Primary Schools was obtained. The respondents were randomly selected. The questionnaire was used for data collection. A 1-4 Likert-type scale ranging from Strongly Agreed to Strongly ...

Energy Technology Data Exchange (ETDEWEB)

The batchwise preparation of molecular sieves for methanol conversion shows some inconsistency in catalytic stability. This is a result mainly of the change of SiO/SUB/2/Al/SUB/2O/SUB/3 in ion exchange to an H-type sieve. The dealumination during ion exchange depends upon crystal size and structural factors, which can be characterised by the cyclohexane adsorption of the raw molecular sieve. A high SiO/SUB/2/Al/SUB/2O/SUB/3 H-molecular sieve can be prepared from a molecular sieve of high adsorption capacity, this leading to a catalyst of higher stability. (4 refs.)

British Library Electronic Table of Contents (United Kingdom)

Palladium silicide was formed on the sol-gel derived SiO2 supported Pd catalysts prepared by ion-exchange method (Pd/SiO2-SG-ion). However, the catalysts exhibited superior performances than commercial SiO2 supported ones in liquid-phase semihydrogenation of phenylacetylene. It was probably due to an inhibition of a product of styrene, which is adsorbed on the surface of Pd, more strongly on Pd/SiO2-SG in which Pd is electron-deficient as shown by larger binding energy from XPS results.

British Library Electronic Table of Contents (United Kingdom)

One-pot multi-component condensation of benzyl, aldehydes, ammonium acetate and primary amines were used for synthesis of 2,4,5-trisubstituted and 1,2,4,5-tetrasubstituted-1H-imidazole derivatives under MW radiation using amberlyst A-15 as a catalysts. This catalyst has several advantages (simple work-up, low cost and reusability).

British Library Electronic Table of Contents (United Kingdom)

It was demonstrated that R 2?R 4 saturated monohydric alcohols can be synthesized from CO and H2 in the presence of Fe catalysts containing a carbon support of the Sibunit type with granule sizes of 3?5, 1?2, and 0.05?0.1 mm in a fixed-bed reactor at 3 MPa and 240?300?C. It was found that the activity of Fe/Sibunit catalysts and their selectivity for the formation of liquid synthetic products increased with the size of granules and the amount of iron. The catalysts make it possible to obtain fatty alcohols, in which the fraction of R 2?R 4 alcohols is as high as 75%, in yields to 56 g/m3.

International Nuclear Information System (INIS)

Graphical abstract: - Abstract: Low loading platinum-cobalt (Pt-Co) cathode catalyst on a Nafion(Na+)-bonded carbon layer is fabricated by using galvanostatic pulse technique to show the advantage of electrodeposition for high utilization of catalyst in proton exchange membrane fuel cell (PEMFC). We observed that Pt-Co catalysts evenly exist on the surface of carbon electrode and its thickness is about 5.8 ?m, which is four times thinner than conventional Pt/C. Improved single cell power performance of Pt-Co cathode catalysts with a ratio of 3.2:1 compared with Pt/C is clearly presented.

Energy Technology Data Exchange (ETDEWEB)

The photocatalyzed degradation of pyridine in the gas phase was investigated using titanium dioxide semiconductor supported on mordenite. The complete mineralization was found to occur over a catalyst containing 75 wt% TiO{sub 2} and 25 wt% mordenite in about 180 min in the presence of saturated water vapor at O{degrees}C (4.6 Torr). Low water vapor pressure of 0.096 Torr was found to be sufficient to achieve a reasonably high percentage and rate of degradation. Diffusion of pyridine within the catalyst adversely affects the activity when the thickness of the catalyst coating exceeds the penetration depth of illumination. The activity of the zeolite-supported catalysts was higher than that of TiO{sub 2}. The photonic efficiency for the complete mineralization of pyridine to CO{sub 2} was determined to be 0.48. 29 refs., 6 refs., 1 tab.

British Library Electronic Table of Contents (United Kingdom)

A new method of the synthesis of high molecular polybutylene terephthalate (PBT) is developed with the use of Irganox 1010, tris(nonylphenyl) phosphite and hypophosphite as stabilizers and boron nitride or boron oxide as a catalyst is proposed.

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Acrylonitrile is a versatile intermediate and is produced by the Sohio ammoxidation process world-wide at a level of 8 billion pounds per year. In the catalytic process, propylene, ammonia and air are converted to acrylonitrile directly. The most widely used catalysts are mixed metal molybdates or antimonates. The current investigation deals with metal tellurates as possible low temperature ammoxidation catalysts. Of the catalysts investigated, iron-selenium-tellurates are of particular interest since they exhibit good ammoxidation activity already at 320/sup 0/C which is about 100/sup 0/C lower than the temperature required for molybdate or antimonate systems. Mechanistically, the tellurates behave more similarly to the antimonates than the molybdates. 3 tabs., 4 figs., 13 refs.

International Nuclear Information System (INIS)

Isopropyl chloroacetate has been synthesized by esterification of chloroacetic acid and isopropanol, using lanthanum dodecyl sulfate (LDDS) as the catalyst. Various factors that affected the esterification have been investigated, such as reaction time, different water-carrying agent and the amount of catalyst. Under the condition of 1.2/1 molar ratio of isopropanol to chloroacetic acid, 1.0% catalyst (molar percent of chloroacetic acid), 2.5 h reaction time, 5 mL cyclohexane as water-carrying agent and reflux temperature, the esterification conversion of isopropyl chloroacetate reaches 98.3%. The catalytic activity of LDDS is almost equal to that of a Bronsted acid. LDDS, as one kind of water-tolerant Lewis acid, is an excellent catalyst compared to the traditional Lewis acid. (author)

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Alkali metal doped double perovskites containing manganese and at least one of cobalt, iron and nickel are useful in the oxidative coupling of alkane to higher hydrocarbons.

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Platinum(II) complexes have been investigated in the hydration of alkynes. These catalysts offer improved regioselectivity over Hg(II) counterparts. 1 fig., 2 tabs.

British Library Electronic Table of Contents (United Kingdom)

The mechanism of the IndolPhos-Rh-catalyzed asymmetric hydrogenation of prochiral olefins has been investigated by means of X-ray crystal structure determination, kinetic measurements, high-pressure NMR spectroscopy, and DFT calculations. The mechanistic study indicates that the reaction follows an unsaturate/dihydride mechanism according to Michaelis-Menten kinetics. A large value of KM (KM=5.01+-0.16 M) is obtained, which indicates that the Rh-solvate complex is the catalyst resting state, which has been observed by high-pressure NMR spectroscopy. DFT calculations on the substrate-catalyst complexes, which are undetectable by experimental means, suggest that the major substrate-catalyst complex leads to the product. Such a mechanism is in accordance with previous studies on the mechanism...

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Ni catalysts supported on {gamma}-Al{sub 2}O{sub 3}, CeO{sub 2} and CeO{sub 2}-Al{sub 2}O{sub 3} systems were tested for catalytic CO{sub 2} reforming of methane into synthesis gas. Ni/CeO{sub 2}-Al{sub 2}O{sub 3} catalysts showed much better catalytic performance than either CeO{sub 2}- or {gamma}-Al{sub 2}O{sub 3}-supported Ni catalysts. CeO{sub 2} as a support for Ni catalysts produced a strong metal-support interaction (SMSI), which reduced the catalytic activity and carbon deposition. However, CeO{sub 2} had positive effect on catalytic activity, stability, and carbon suppression when used as a promoter in Ni/{gamma}-Al{sub 2}O{sub 3} catalysts for this reaction. A weight loading of 1-5wt% CeO{sub 2} was found to be the optimum. Ni catalysts with CeO{sub 2} promoters reduced the chemical interaction between nickel and support, resulting in an increase in ...

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Standard SCR catalysts possess high activity for the hydrolysis of HNCO and thus explain the suitability of urea as a selective reducing agent for NO{sub x}. At high space velocities HNCO-slip can get perceptible over the entire temperature range. This can be attributed to the fact that the temperature dependence is strong for the SCR reaction, but weak for the hydrolysis reaction. (author) 3 figs., 5 refs.

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On handling nitric solutions in the glove box nitrous gases are formed that are sucked off via a heated activated charcoal filter and a catalyst cartridge containing e.g. the FG 590 H catalist (Degussa). By the activated charcoal the nitrous gases are reduced to N/sub 2/ and CO gas; the catalyst will oxidize CO to CO/sub 2/. The CO/sub 2/ obtained is discharged through an exhaust air filter in the glove box.

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CeO{sub 2}-TiO{sub 2} 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. CeO{sub 2}-TiO{sub 2} mixed oxides show the higher activity than pure CeO{sub 2} and TiO{sub 2}, and CeO{sub 2}-TiO{sub 2} 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 CeO{sub 2}-TiO{sub 2} 1/1 catalyst at reaction temperature of 150 {sup o}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 CeO{sub 2}-TiO{sub 2} 1/1 particle catalyst, over 91% COD and 80% TOC removals are obtained at the reaction temperature of 140 {sup o}C, the air total pressure of 3.5 MPa, the phenol ...

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Process solvent was hydrogenated in the brown coal liquefaction, to investigate the influence of it on the prethermal treatment and liquefaction. Consequently, it was found that the n-hexane soluble (HS) yield was improved. In this study, capacity of hydrogen transfer from solvent during prethermal treatment and effects of catalyst were investigated. Since prethermal treatment in oil was effective for improving the oil yield in the presence of hydrogen/catalyst or high hydrogen-donor solvent, influence of hydrogen-donor performance of solvent or addition of catalyst on the hydrogenation behavior of coal and the characteristics of products during prethermal treatment were investigated in relation to successive liquefaction results. As a result, it was found that the increase of HS yield was due to the acceleration of conversion of THF-insoluble using high hydrogen-donor solvent and/or by adding catalyst. ...

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This patent describes a process for the preparation of acrylonitrile or methacrylonitrile by the reaction of propylene or isobutylene, molecular oxygen and ammonia at a temperature of about 200/sup 0/ to 600/sup 0/C in the presence of an oxidation catalyst. The improvement consists of using as the oxidation catalyst an antimony-free catalyst having the atomic ratios described by the formula: X/sub a/A/sub b/C/sub c/Fe/sub d/Bi/sub e/Mo/sub 12/O/sub x/ wherein X is Ga, In or mixtures thereof; A is alkali metal; C is Ni, Co or mixture thereof; and wherein a is 0.01 to about 4; b is 0 to about 4; c and d are 0.01 to about 12; e is 0.01 to about 6; and x is a number sufficient to satisfy the valence requirements of the other elements present. In a process for the preparation of acrylonitrile or methacryloniotrile by the reaction of propylene or isobutylene, molecular oxygen and ammonia at a temperature of about 200/sup 0/ to ...

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It is thought that iron-based catalysts for coal liquefaction exercise their catalytic activity by forming pyrrhotite (Fe(1-x)S). However, there are still a lot of unknown problems remained concerning the formation and agglomeration behaviors of pyrrhotite. These make a difficulty for improving the activity of iron-based catalysts. In this study, sulfiding behaviors of {alpha}-iron oxyhydroxide ({alpha}-FeOOH) and {gamma}-iron oxyhydroxide ({gamma}-FeOOH) were investigated to reveal the formation and agglomeration behaviors of pyrrhotite. It was found that pyrrhotite was easily converted from ferric oxyhydroxide catalysts having large specific surface areas at the sulfiding temperature below 250{degree}C, and fine crystallites of pyrrhotite were formed at the initial stage of sulfiding. Crystal growth of pyrrhotite at the sulfiding temperature over 350{degree}C depended on the catalyst forms. It was ...

International Nuclear Information System (INIS)

Palladium/magnetite nanoparticulate catalysts were developed for efficient elimination of halogenated organic pollutants from contaminated wastewater. Particle recovery from treated water can be ensured via magnetic separation. However, in worst-case scenarios, this catalyst removal step might fail, leading to particle release into the environment. Therefore, a toxicological study was conducted to investigate the impact of both pure magnetite and palladium/magnetite nanoparticle exposure upon human skin (HaCaT) and human colon (CaCo-2) cell lines and a cell line from rainbow trout gills (RTgill-W1). To quantify cell viability after particle exposure, three endpoints were examined for all tested cell lines. Additionally, the formation of reactive oxygen species was studied for the human cells. The results showed only minor effects of the particles on the tested cell systems and support the assumption that palladium/magnetite ...

Science.gov (United States)

In October 1980, Air Products and Chemicals, Inc. began a three year contract with the DOE: Catalyst and Reactor Development for a Liquid Phase Fischer-Tropsch Process. The program contains four major tasks: (1) Project Work Plan, (2) Slurry Catalyst Development, (3) Slurry Reactor Design Studies, and (4) Pilot Facility Design. This report describes work on Tasks 2 and 3 carried out in the third quarter of the contract. In Task 2, the computerized search of the Fischer-Tropsch literature was continued, and improvements were made in data processing programs. Shakedown tests were completed on the first 300 ml slurry reactor, and construction of the second and third reactors began. Five modified conventional slurry catalysts were prepared, and two batches were tested in the gas phase giving information on selectivity as a function of composition and activation. Four supported cluster catalyst were ...

Science.gov (United States)

This report presents the results of Run 261 performed at the Advanced Coal Liquefaction R & D Facility in Wilsonville, Alabama. The run started on January 12, 1991 and continued until May 31, 1991, operating in the Close-Coupled Integrated Two-Stage Liquefaction mode processing Illinois No. 6 seam bituminous coal (from Burning star No. 2 mine). In the first part of Run 261, a new bimodal catalyst, EXP-AO-60, was tested for its performance and attrition characteristics in the catalytic/catalytic mode of the CC-ITSL process. The main objective of this part of the run was to obtain good process performance in the low/high temperature mode of operation along with well-defined distillation product end boiling points. In the second part of Run 261, Criterion (Shell) 324 catalyst was tested. The objective of this test was to evaluate the operational stability and catalyst and process performance while processing the high ash ...

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... Biogas Analyzers Equipment on Environmental Expert Find and compare a variety of biogas analyzers equipment on the world's largest environmental industry portal. View ...

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Sulfur poisoning from engine fuel and lube is one of the most recognizable degradation mechanisms of a NOx adsorber catalyst system for diesel emission reduction. Even with the availability of 15 ppm sulfur diesel fuel, NOx adsorber will be deactivated without an effective sulfur management. Two general pathways are currently being explored for sulfur management: (1) the use of a disposable SOx trap that can be replaced or rejuvenated offline periodically, and (2) the use of diesel fuel injection in the exhaust and high temperature de-sulfation approach to remove the sulfur poisons to recover the NOx trapping efficiency. The major concern of the de-sulfation process is the many prolonged high temperature rich cycles that catalyst will encounter during its useful life. It is shown that NOx adsorber catalyst suffers some loss of its trapping capacity upon high temperature lean-rich exposure. With the use of a disposable SOx ...

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The effect of thermal pretreatment in N[sub 2] up to 723 K and the activation treatments in H[sub 2] and an inert atmosphere on the properties of Ni and Co activated-charcoal-supported catalysts were studied. Catalysts were characterized by means of N[sub 2] adsorption at 77 K, H[sub 2] chemisorption at room temperature, thermogravimetric analysis (TGA), X-ray diffraction (XRD), and transmission electron microscopy (TEM). The catalysts' activity and selectivity for acetone hydrogenation to 2-propanol under unusual and severe conditions (473 K and high overall acetone conversion) were also measured. TGA and XRD evidence was found for the charcoal-support-promoted NiO and CoO reduction to the metallic states when the catalysts were subjected to an inert atmosphere above 723 K caused a loss of acetone hydrogenation activity (calculated on a metal load basis) for both the Ni and Co ...

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Selective catalytic reduction (SCR) of nitrogen oxides(NO{sub x}) in flue gas or engine exhaust gas with hydrocarbons as the reductant has great potential for less expense, less pollution, and easier operation than SCR with ammonia. Methane is the preferred reducing gas because of its low cost and low toxicity. Stable, low-cost catalysts for SCR with methane are required to demonstrate this technology for controlling NO{sub x} emissions. Several cobalt and nickel catalysts on synthetic clay and uranium oxide supports were investigated for their activities in reducing NO{sub x} with methane in the presence of air. The efficiency of the synthetic clay-supported nickel and cobalt catalysts for nitric oxide (NO) reduction with methane as the reducing gas was poor. The nickel oxide-uranium oxide catalyst, which was chosen for its high stability, was also ineffective. Results from the two-step experiments ...

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In pre-experiments a tubular reactor was checked whether it is suitable for kinetic measurement on the system of the silver-catalysed partial oxidation of methanol to formaldehyde. Detrimental effects of heat-transfer and mass-transfer on the experimental results were ruled out. Investigations on the characteristics of the reaction showed that it is possible to manipulate the composition of the product mixture by changing the inlet concentration of the reactants. A modified power-law model was established to describe the reaction kinetics. It considers the preadsorption step of oxygen on the catalysts surface and fits the experimental data quite well. During the rapid oxidation the catalysts surface undergoes a drastic change. It gets coarse and has an adsorption capacity of 11 m{sup 2}/g after being exposed to the reaction mixture. (orig.)

Science.gov (United States)

Porcine pancreatic lipase immobilized on celite particles has been employed as a catalyst for the esterification of dodecanol and decanoic acid in a predominantly organic system. Solvent influence on the equilibrium position and on the catalyst activity has been studied using 20 solvents, including aliphatic and aromatic hydrocarbons, ethers, ketones, nitro- and halogenated hydrocarbons, and esters. The equilibrium constant for esterification correlates well with the solubility of water in the organic solvent, which in turn shows a good relationship with a function of Guttman's donor number and the electron pair acceptance index number of the solvent. This may be rationalized in terms of the requirements for solvation of water and of the reactants. The catalyst activity, measured as the initial rate of the esterification reaction, is best correlated as a function of both n-octanol-water partition coefficient (log P) and ...

British Library Electronic Table of Contents (United Kingdom)

A dense Pd-Ag membrane reactor (MR) with 100% hydrogen selectivity packed with either Rh/La2O3 or Rh/La2O3-SiO2 as catalysts was used to carry out the dry reforming of methane. The membrane reactor simulation was performed using a well-known reactor model. For this purpose, we employed the equations derived from complete kinetic studies of the dry reforming of methane reaction in connection with both catalysts. In addition, we developed the kinetic equation for the reverse water gas shift reaction (RWGS). The combination of detailed kinetic studies with the measured permeation flux for the Pd-Ag membrane allowed a complete comparison between experimental and simulated operation variables. The variables studied for both catalysts were methane conversion and hydrogen permeation as a function...

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A kinetic model based on the Mars-van Krevelen mechanism that allows to describe the microkinetics of the heterogeneously catalysed partial oxidation of {alpha}, {beta}-unsaturated aldehydes is presented. This conversion is represented by a network, composed of the oxidation of the {alpha}, {beta}-unsaturated aldehyde towards the {alpha}, {beta}-unsaturated carboxylic acid and the consecutive oxidation of the acid as well as the parallel reaction of the aldehyde to products of deeper oxidation. The reaction steps of aldehyde respectively acid oxidation and catalyst reoxidation have been investigated separately in transient experiments. The combination of steady state and transient experiments has led to an improved understanding of the interaction of the catalyst with the aldehyde and the carboxylic acids as well as to a support of the kinetic model assumptions. (orig.)

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Hydrogenation of napthalene to tetralin using activated red mud as catalyst was studied as a typical hydrogen-donor system. Under the chosen reaction conditions, unprocessed red mud resulted in a conversion of napthalene of 3.55%. The most active catalyst, prepared by adding 20 wt% of TiO/SUB/2 to the red mud, followed by acid digestion and re-precipitation, resulted in a 58% conversion of naphthalene. This technology may have an important bearing on processes such as coal hydrogenation or crude-oil-residue processing, where the rate of reaction and product quality may depend upon the rate at which a hydrogen-donor solvent can be re-hydrogenated. (7 refs.)

British Library Electronic Table of Contents (United Kingdom)

Abstract Dynamic testing of a phosphoric acid-based high temperature PEM fuel cell shows a peculiar phenomenon. A certain current loss is observed after temperature cycling at constant voltage. This loss is incidentally recovered by applying a cell voltage spike to open circuit voltage. Experimental investigations into temperature, cell voltage, and ageing effects show that this phenomenon might occur due to the orientation of the adsorbed phosphate species on the platinum catalyst surface. Along with some supporting literature and experimental results, a hypothesis is presented in order to explain this occurrence. Phosphoric acid adsorption hysteresis on platinum catalyst due to temperature cycling could cause the temporary cell current loss. Electrode potential-dependent molecule symmetr...

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A residue in the production of alumina by the Bayer process is red mud. It contains oxides of Fe and Ti, active as hydrogenation catalyst in sulfided form, and whose catalytic activity can be improved by the activation method proposed by Pratt and Christoverson. The paper describes how the development of its activity and selectivity with reaction time was studied for the hydrogenation of a light fraction of an anthracene oil, and compared with untreated sulfided red mud. Catalyst samples were collected at different reaction times, and their texture, morphology and composition characterized by nitrogen adsorption, SEM and SEM-EDX. The loss of catalytic activity of activated sulfided red mud is slower than for untreated sulfided red mud. The main cause of this decrease in catalytic activity is the loss of surface area and superficial Fe.

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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).

British Library Electronic Table of Contents (United Kingdom)

A new heterogeneous catalyst for the esterification of free fatty acids and the transesterification of vegetable oils is reported. The layered compound zinc hydroxide nitrate (Zn5(OH)8(NO3)22H2O) was very effective in the alcoholysis of palm oil and the esterification of lauric acid with m(ethanol), even when hydrated ethanol was used. Over the range of 100-140degreeC, the ester yield was the highest at 140degreeC, while the catalyst concentration had a much greater effect on ester yields than the molar ratio of alcohol to acid did. Total ester contents above 95wt% were obtained in both reactions and 93.2wt% glycerin streams were recovered as a result of methanolysis.

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Correlations between structural aspects of solid materials and their behavior as catalysts are relatively recent. This 20-chapter book focuses on understanding of solid-state mechanisms in heterogeneous catalysis and relationship between catalytic behavior and solid state structure, emphasizing catalysis with oxides, sulfides, and zeolites.

International Nuclear Information System (INIS)

A series of silylated Co/SBA-15 catalysts were prepared via the reaction of surface Si-OH of SBA-15 with hexamethyldisilazane (HMDS) under anhydrous, vapor-phase conditions, and then characterized by FT-IR, N2 physisorption, TG, XRD, and TPR-MS. The results showed that organic modification led to a silylated SBA-15 surface composed of stable hydrophobic Si-(CH3)3 species even after calcinations and H2 reduction at 673 K. Furthermore, the hydrophobic surface strongly influenced both metal dispersion and reducibility. Compared with non-silylated Co/SBA, Co/S-SBA (impregnation after silylation) showed a high activity, due to the better cobalt reducibility on the hydrophobic support. However, S-Co/SBA (silylation after impregnation) had the lowest FT activity among all the catalysts, due to the lower cobalt reducibility along with the steric hindrance of grafted -Si(CH3)3 for the re-adsorption of ?-olefins. -- Graphical abstract: The silylation of ...

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Propylene polymerizations were carried out with {phi}{sub 2}C(Flu)(Cp)ZrCl{sub 2} and SiMe{sub 2}(Ind)2ZrCl{sub 2} catalysts supported on silica, zeolite sodic mordenite (NaM) and acid mordenite (HM). The polymerizations were performed at different temperatures and varying aluminium/zirconium molar ratios ([Al]/[Zr]). The effect of these reaction parameters on the catalyst activity was investigated using a proposed statistical experimental planning. In the case of f{sub 2}C(Flu)(Cp)ZrCl{sub 2}, SiO{sub 2} and NaM were used as support and the catalyst performance evaluated using toluene and pentane as polymerization solvent. The molecular weight, molecular weight distribution, melting point and crystallinity of the polymers were examined. The results indicate very high activities for the syndiospecific heterogeneous system. Also, the polymers obtained had superior Mw and stereo regularity. (author)

Science.gov (United States)

A laboratory-scale well-mixed thermostatic reactor with continuously blasting air was used to investigate the oxidation inhibition of sulfite in dual alkali flue gas desulfurization (FGD) system. The effects of operating parameters such as pH value and catalyst concentration on the oxidation were studied. Sodium thiosulfate was used in the system, and was found that it significantly inhabited the sulfite oxidation. In the absence of catalyst, sodium thiosulfate at 12.67 mmol/L had an inhibition efficiency of approximately 98%. While in the presence of catalyst, sodium thiosulfate at 26.72 mmol/L had an inhibition efficiency less than 85.0%. The oxidation reaction order of sulfite in the sodium thiosulfate was determined to be -1.90 and -0.55 in the absence and presence of the catalyst, respectively. Apparent activation energy of oxidation inhibition was calculated to be 53.9 kJ/mol. Pilot tests showed ...

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...wood smoke, emissions, pollution, heaters, environment, Earthbeat - 25/5/2002: Woodsmoke, Health & the Environment Love that Planet All in the Mind The Buzz Health Report In Conversation Ockhams Razor Science Show The Lab Health Matters Catalyst Quantum ...

Energy Technology Data Exchange (ETDEWEB)

Work continued on the correlations of catalytic activity of metals and surface structure. Work is described in the following areas: CO oxidation on a Cu/Rh(100) Bimetallic catalysts; electronic properties of bimetallic surfaces; and reflection absorption spectroscopy of bimetallic surfaces. 5 figs. (CBS)

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This thesis is in the field of gas emission control from automobile and stationary sources. Out of the possible approaches to the elimination of pollutant gases, such as nitrogen oxides (NO{sub x}), one consists in the selective catalytic reduction (SCR) of these NO{sub x} on a suitable heterogeneous catalyst. Ammonia or hydrocarbons are employed as reducing agents. The most important catalysts active in the SCR of NO{sub x} are based on ions of transition metal either supported on several oxides or dispersed in zeolites. The catalysts have been characterized by electron magnetic resonance techniques (EPR, ENDOR, ESEEM) and the interaction of catalysts with nitrogen oxides, with reducing and poisoned agents have been followed with the same techniques. Copper dispersed on alumina and its interaction with both NO and ammonia has been investigated. Also the interaction between both water and ammonia with ...

Energy Technology Data Exchange (ETDEWEB)

Modern combined cycle power plants with natural gas as the only fuel reach efficiencies of up to 58% for electric power generation. Nevertheless the reserves of natural gas are more limited compared to the reserves of coal. Therefore possibilities should be investigated to use coal for such plants also. One concept, that combines the use of coal in a combined cycle application with high efficiencies is examined in this paper. According to this concept the exhaust gas of the gas turbine (vitiated air) is the combustion air for the pulverised coal combustion, that takes place in the bottoming steam generator. Due to the low oxygen content of the vitiated air the burnout of the coal may be incomplete. In order to avoid the incomplete combustion of the coal and the resulting decrease of the efficiency of the plant and possible emission problems, a catalyst, that converts carbon monoxide and unburnt carbon to carbon dioxide should be installed between the heating ...

Energy Technology Data Exchange (ETDEWEB)

Despite the rapid development of literature pertaining to fundamental (1-4) studies of oxidation catalysis, a general theory of heterogeneous selective oxidation catalysis explaining the selectivity behavior of different metal oxide systems has not yet been developed. Redox mechanisms have been widely invoked in the kinetic and mechanistic descriptions of selective oxidation reactions, suggesting a dynamic behavior of hydrocarbon and oxygen interactions with the catalyst surface. Nevertheless, most of the recent theoretical approaches of this subject matter (5-7) are essentially static in nature. Correlations are made with surface structure on the basis of crystallographic considerations with selectivity being related to the nature, number, bond-strength and nearness of oxygen atoms in the neighborhood of adsorption centers. The effect of the reaction medium on the configuration of the catalyst surface, and thus its influence on the reaction ...

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An investigation of the effect of blending of two different coals in various ratios on the hydrogenation reaction was carried out using a red mud-sulphur catalyst. Three Japanese coals and an Australian brown coal were used in the study. The conversion of the blended coals was compared with that obtained with each of the coals alone. A blend of the Yallourn brown coal and Shin-Yubari coal showed a synergism: it is considered that hydroaromatics from the Japanese coal promote the hydrogenation of the Yallourn coal. (The tables and captions in this paper are in English).

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Applying the thermochemical selectivity criterion of Hadnett et al. It is shown that the selectivity of the furan formation is not limited by a too low strength of the C-H bonds in furan when compared with the C-H bond dissociation energy in the educt molecule butadiene. In the oxidation of butadiene on a CsH{sub 2}PMo{sub 12}O{sub 40} catalyst a maximum yield of 22 mol% furan has been obtained. To improve this comparatively low furan yield oxidation activity of the catalyst must be lowered to prevent the consecutive reaction to maleic anhydride. (orig.)

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The authors measured the absorption of CO{sub 2} in alkaline 0.5 M/0.5 M sodium carbonate/bicarbonate buffers containing either saccharose and sodium arsenite or saccharose and formaldehyde. Absorption enhancement increased upon increasing the concentration of either of the catalysts, but the joint action of the two was always less than the sum of their individual effects, the difference being a function of the acidities and concentrations of the catalysts and the pH of the carbonate/bicarbonate buffer solution

Energy Technology Data Exchange (ETDEWEB)

Hydrogenolysis reactions of a mixture of coal liquid and coal liquefaction residue were carried out using red mud - sulfur or Co-Mo/Al{sub 2}O{sub 3} catalyst. The effect of deashing treatment of coal liquefaction residue were also investigated. Notable synergistic effects such as the increase of n-hexane soluble and the decrease of dichloromethane insoluble were observed only with the hydrogenolysis of the basic fraction of coal liquid and nondeashed coal liquefaction residue using red mud-sulfur catalyst. 4 refs., 2 figs., 2 tabs.

Energy Technology Data Exchange (ETDEWEB)

Among the items of the Sunshine Project in fiscal 1981 for development of a solvent extraction and liquefaction plant, this paper describes the achievements in developing secondary hydrogenation. A small continuous hydrogenation device equipped with three reaction columns that can be filled with catalyst of 50 cc, and a dedicated testing room were designed, and orders were placed with manufacturers. The fabrication, assembly, delivery, installation, piping and wiring were all completed. The device passed a completion inspection based on the high-pressure gas safety assurance law in December 1981. After leakage due to gas and material oil was checked, a trial operation was performed, and verified of normal operation. A screening test was carried out on three kinds of commercially available and prototype catalysts before testing the SRC containing material for studying the secondary hydrogenation. The circulating solvent having a boiling point ...

Energy Technology Data Exchange (ETDEWEB)

The current work continues a project completed in 1999 by ReMaxCo Technologies in which a novel, microwave based, VLS Silicon Carbide Fibrils concept was verified. This project continues the process development of a pilot scale commercial reactor. Success will lead to sufficient quantities of fibrils to expand work by ORNL and others on heat exchanger tube development. A semicontinuous, microwave heated, vacuum reactor was designed, fabricated and tested in these experiments. Cylindrical aluminum oxide reaction boats are coated, on the inner surface, with a catalyst and placed into the reactor under a light vacuum. A series of reaction boats are then moved, one at a time, through the reactor. Each boat is first preheated with resistance heaters to 850 C to 900 C. Each reaction boat is then moved, in turn, to the microwave heated section. The catalyst is heated to the required temperature of 1200 C to 1300 C while a mixture of MTS (methyl ...

Science.gov (United States)

The overall objective of this project was to develop a new approach for the direct liquefaction of coal to produce an all-distillate product slate at a sizable cost reduction over current technology. The approach integrated coal selection, pretreatment, coal swelling with catalyst impregnation, liquefaction, product recovery with characterization, alternate bottoms processing, and a technical assessment including an economic evaluation. Heterofunctional solvents were the most effective in swelling coals. Also solvent blends such as isopropanol/water were more effective than pure solvents alone. Impregnating slurry catalysts simultaneously during coal swelling showed that better uptake was achieved with nonswelling solvent and higher impregnation temperature. Some enhancement in initial coal conversion was seen liquefying SO{sub 2}-treated Black Thunder coal with slurry catalysts, and also when hydrogen donor liquefaction ...

Energy Technology Data Exchange (ETDEWEB)

{sup 14}C is a is a long-lived beta-emitting nuclide (T{sub 1/2} = 5730 years) produced naturally in the upper atmosphere as a result of reactions between neutrons and stable {sup 14}N({sup 14}N(n,p){sup 14}C). Although in a lesser extent, nuclear power plants produce {sup 14}C as well during their routine operation. Since it is converted in {sup 14}CO{sub 2} and mixed throughout the atmosphere, it is incorporated into plant tissues, via photosynthesis process, and hence in food chain. Because of the biological importance of {sup 14}C and long half-life, it is of interest to quantify the amounts released by nuclear industry. The Brazilian nuclear central named Nuclear Central Admiral Alvaro Alberto (CNAAA) has two nuclear reactors of PWR type in operation, Angra I (657 MWe) and Angra II (1350 MWe), and one under construction, Angra III (1309 MWe PWR). The aim of this study was to determine the strength of the sources and the {sup 14}C content in the environment through analyses of air, ...

Energy Technology Data Exchange (ETDEWEB)

The behaviour of two different catalytic precursors based on iron (FeSO{sub 4}.7H{sub 2}O) and Fe{sub 2}O{sub 3} in direct hydroconversion of two coals are studied in this paper. Coal itself was the catalytic support of the dispersed iron sulfide (from iron sulfate); when the catalyst precursor was iron oxide (from red mud), coal and catalyst were directly mixed as powders. The reaction conditions were: 10 MPa (H{sub 2}, cold) initial pressure, 30 min, and reaction temperatures of 300, 350, 400, and 425{degree}C, reaching 450 and 500{degree}C for the high-rank coal. The results from Moessbauer spectroscopy demonstrate that pyrite in all the runs, inherent to coal or added as catalyst precursor, is converted into pyrrhotite to a variable extent according to the previous iron distribution and the iron chemical state in the catalyst precursors as well as the CS{sub 2} addition. Important chemical and ...

Science.gov (United States)

This report presents the operating results for Run 245 at the Advanced Coal Liquefaction R and D Facility in Wilsonville, Alabama. This run was made in an all-distillate Integrated Two-Stage Liquefaction (ITSL) mode using Illinois 6 coal from the Burning Star mine. The primary run objective was to obtain steady-state ITSL performance by replacing spent HTR reactor catalyst with fresh, sulfided catalyst. Secondary objectives were to maintain an all-distillate (minimum resid production) product slate and to demonstrate the effects of catalyst addition on the net gas production and hydrogen consumption. Run 245 began on 7 November, 1983, and continued through 12 February, 1984. During this period, 179.0 tons of coal was fed in 2045 hours of operation. Eight special product workup material balances were defined, and the results are presented herein. 6 references, 28 figures, 20 tables.

Energy Technology Data Exchange (ETDEWEB)

Essential to today's modern refineries and the gasoline production process are fluidized catalytic cracking units. By using a computational fluid dynamics (CFD) code developed at Argonne National Laboratory to simulate the riser, parametric and sensitivity studies were performed to determine the effect of catalyst inlet conditions on the riser hydrodynamics and on the product yields. Simulations were created on the basis of a general riser configuration and operating conditions. The results of this work are indications of riser operating conditions that will maximize specific product yields. The CFD code is a three-dimensional, multiphase, turbulent, reacting flow code with phenomenological models for particle-solid interactions, droplet evaporation, and chemical kinetics. The code has been validated against pressure, particle loading, and product yield measurements. After validation of the code, parametric studies were performed on various parameters such ...

Energy Technology Data Exchange (ETDEWEB)

For the coal liquefaction, improvement of liquefaction conditions and increase of liquefied oil yield are expected by suppressing the recombination through rapid stabilization of pyrolytic radicals which are formed at the initial stage of liquefaction. Two-stage liquefaction combining prethermal treatment and liquefaction was performed under various conditions, to investigate the effects of reaction conditions on the yields and properties of products as well as to increase liquefied oil yield. Consequently, it was found that the catalyst contributes greatly to the hydrogen transfer to coal at the prethermal treatment. High yield of n-hexane soluble fraction with products having low condensation degree could be obtained by combining the prethermal treatment in the presence of hydrogen and catalyst with the concentration of slurry after the treatment. This was considered to be caused by the synergetic effect between the improvement of ...

International Nuclear Information System (INIS)

A process is described for the selective oxidation of ammonia to nitric oxide in about 90% or greater yield with a minimum of nitrogen or dinitrogen oxide (N/sub 2/O) as by-products, comprising: (1) contacting gaseous ammonia in an oxygen containing gas optionally with an inert gaseous diluent with a mixed metal perovskite catalyst of the general formula: ABO/sub 3/, wherein: A is selected from the alkali, alkaline earth, lanthanide, or actinide metals or a mixture of these metals having a relatively large ionic, radius, and B is selected from an element or a combination of elements selected from Groups IB, IVB, VB, VIB, VIIB, or VIII of the Periodic Table, wherein the perovskite phase of the catalyst has an equilibrium partial pressure of oxygen at 1000"0C of greater than about 10/sup -15/ bar; and (2) heating the reactants of step (1) at greater than about 500"0C under conditions of 10 to 100,000 hr/sup -1/ hourly space velocity.

Energy Technology Data Exchange (ETDEWEB)

The selective catalytic reduction of nitric oxide by methane over copper ion-exchanged natural zeolites was investigated in a packed-bed tubular reactor. The catalytic activity of Cu-N and Cu-H-N catalysts was confirmed as NO, CH{sub 4}, and O{sub 2} displayed very little reaction in the absence of any catalyst and zeolite without ion exchange was totally inactive. A maximum NO conversion of 33% at 650 C for Cu-N-66 was achieved with 2% NO and 1% CH{sub 4} and a contact time of 0.9 g s/cm{sup 3}, but the introduction of 2% O{sub 2} reduced the NO conversion to only 12%. Ion exchange for the H-form prior to copper ion exchange was essential for oxygen to promote catalytic activity over the temperature range 250--650 C, with a maximum conversion of 30% at 450 C with O{sub 2} present. The direct reduction of NO by methane was ruled out as a possible reaction pathway.

Energy Technology Data Exchange (ETDEWEB)

Ionic liquids can enhance the activity, selectivity, and stability of enzyme catalysts. Enzymes and ionic liquids as catalysts are seen as a more environmentally friendly technology than the use of traditional catalyst materials in biofuels production. This study investigated the lipase catalyzed esterification reaction for biodiesel production in the presence of the ionic liquid BMIM PF{sub 6}. Methyl acetate was used as the acyl acceptor. A titremetric assay was conducted to measure the activity of the lipase with various amounts of ionic liquid. Reaction parameters were investigated in order to determine their effects on biodiesel conversion. An 80 per cent overall methyl oleate biodiesel yield was successfully produced in the presence of the ionic liquid. The ionic liquid improved lipase activity as well as overall biodiesel yield. Results also showed that the addition of the ionic liquid facilitated the separation of ...

Energy Technology Data Exchange (ETDEWEB)

Taiheiyo coal deashed using acid treatment and loaded with potassium or calcium was hydro-cracked under gaseous phase to discuss effects of these metals on liquefaction reaction. In addition, the loaded coal was added with red mud catalyst to examine effects of the addition. The loaded potassium has a softening power, and particularly the potassium adsorbed into surface and micropores in the coal decomposes selectively HI-BS and BI-PS and generates gas and HS. On the other hand, potassium deposited on coal surface promotes direct gas production from the coal. Irrespective of its loading modes, calcium has a catalytic nature to produce HI-BS selectively. Calcium also acts to impede decomposition of HI-BS into HS. Adding red mud catalyst to potassium loaded coal increases the inversion rate and the liquefaction yield, and most of the increase is accounted for by HI -BS, and BI-PS. When red mud catalyst is added to calcium ...

Science.gov (United States)

The objectives of this contract are to conduct exploratory coal liquefaction research on modified solvents with slurry phase catalysts and on coal pretreatment. This report describes a review of the existing literature as well as currently on-going research in the areas of: (1) solvent quality effects on coal liquefaction; (2) role of heteroatoms in liquefaction of coal; (3) heteroatoms removal through solvent treatment, extraction and hydrogenation; (4) slurry phase catalysts in hydroprocessing of coal; and (5) effect of coal preparation and pretreatment on liquefaction. The review encompasses both technical papers and presentations as well as the patent literature. This report is comprised of two distinct parts. In Part I all the literature available on the effect of solvent quality, heteroatoms, heteroatoms removal, and slurry phase catalysts on coal liquefaction is incorporated. The existing literature and currently ...

Energy Technology Data Exchange (ETDEWEB)

Cyclopropane isomerization to propylene over various Eu[sup 3+] loadings in NaX zeolite have been studied by measurements of steady-state and transient kinetics and by Fourier transform infrared spectroscopy. As Eu[sup 3+] loading increases, the rate of deactivation increases, the conversion increases, apparent activation energies are lowered, and Bronsted acid site strength and amounts increase. Apparent activation energies of 13-15 kcal/mol for propylene formation have been observed for these systems, consistent with literature reports for other metal supported heterogeneous catalyst systems. Deactivation studies have shown that activity can be restored by heating in He at 380[degrees]C between various temperature runs, and that gases desorbed during regeneration are predominantly propylene. Poisoning studies of Bronsted sites with Na vapor lead to deactivation of these catalysts. A reaction mechanism scheme based on [pi] allyl intermediates ...

Energy Technology Data Exchange (ETDEWEB)

This quarterly report for the period July through September 1984 summarizes activities in Sandia National Laboratories' continuing program of coal liquefaction research. The primary goals are to: explore novel catalytic concepts and materials for conversion of coal to liquid fuels; determine the effects of process variables on catalyst deactivation; determine the effects of coal structure and solvent properties on low temperature dissolution; study the kinetics and catalysis of hydrogen transfer reactions; develop an understanding of slurry gelling phenomena; and provide a technical assessment of coal liquefaction processes. During this period, work was performed on: the rheology of Illinois No. 6 coal in hydrogenated creosote oil; dissolution chemistry of subbituminous coal; pyrite catalysis; liquefaction of Illinois No. 6 coal in indole; characterization and activity testing of catalyst samples from Wilsonville Run 246; ...

British Library Electronic Table of Contents (United Kingdom)

Cobalt supported on Beta zeolite catalysts were prepared by impregnation of metal salts in aqueous solution and were tested for the Fischer Tropsch reaction. The support consisted of a Beta zeolite composed by crystallites of nanometric dimensions and a SiO2/Al2O3 molar ratio of about 50. This support was impregnated with Co(NO3)2 aqueous solution using different metal loads of 7.5, 10, 15 and 20wt% Co. These materials were characterized by X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM), N2 adsorption (BET), thermal programmed reduction (TPR) and FTIR of adsorbed pyridine (i.e., surface acid sites distribution). All the catalysts showed a significant catalytic activity for the F-T reaction from synthesis gas (CO+2H2), in a continuous fixed bed reactor sys...

Science.gov (United States)

This topical report presents data and results obtained from the hydrogen microautoclave. The autoclave has been used to test for the quality of hydrotreater residue product and hydrotreater catalyst activity. Data obtained from Run 242 and the first part of Run 243 is presented in a convenient format and conclusions based upon this data are summarized. Some of the topics discussed in this report are the following: development and description of procedures for the catalyst and hydrotreater residue, the significance of test results and their meaning, and the relationship of test results to process performance. 7 references, 13 tables, 22 figures.

International Nuclear Information System (INIS)

The potential use of uranium in the field of catalysis is presented in the first part of this paper. Numerous applications of uranium binary oxides, as well as mixed oxides, are reviewed with a special emphasis on the role of U-Sb-O catalysts in selective oxidation (and ammoxidation) processes. Attempts are made to correlate the electronic structure of uranium, and especially the role that 5f electrons play in bonding, with its promising catalytic properties. In the second part, new data are given for uranium-bismuth mixed oxides in the catalytic oxidation of CO by O_2. Kinetic tests performed in a flow microreactor allow a mechanism to be proposed that involves the direct participation of lattice oxygen of the catalyst in the chemical process (redox mechanism). The high activity can be related to the ability of uranium to change reversibly its oxidation state. (author).

British Library Electronic Table of Contents (United Kingdom)

Natural gas is a promising alternative fuel to meet strict engine emission regulations in many countries. Natural gas engines can operate at lean burn and stoichiometric conditions with different combustion and emission characteristics. In this paper, the operating envelope, fuel economy, emissions, cycle-to-cycle variations in indicated mean effective pressure and strategies to achieve stable combustion of lean burn natural gas engines are highlighted. Stoichiometric natural gas engines are briefly reviewed. To keep the output power and torque of natural gas engines comparable to those of their gasoline or Diesel counterparts, high boost pressure should be used. High activity catalyst for methane oxidation and lean deNOx system or three way catalyst with precise air-fuel ratio control str...

Energy Technology Data Exchange (ETDEWEB)

X-ray photoelectron spectroscopy measurements indicate that the Ce{sup 3+} like fraction in {gamma}-Al{sub 2}O{sub 3} supported CeO{sub 2} can be decreased by the incorporation of La{sup 3+}. If La{sup 3+} is incorporated into the {gamma}-Al{sub 2}O{sub 3} before CeO{sub 2} is added, a higher CeO{sub 2} dispersion and a greater range of reversible reducibility of the CeO{sub 2} may also be obtained. These changes offer potential for improvement in the oxygen storage capacity provided by CeO{sub 2} in three-way catalysts. The actual effect of La{sup 3+} incorporation on the activity and durability of a Pt catalyst is assessed by a combination of temperature programmed reduction and flow reactor measurements.

British Library Electronic Table of Contents (United Kingdom)

Nowadays, the studies are focused on the search of better electrocatalysts that promote the complete oxidation of ethanol/bioethanol to CO2. To that end, amorphous bi-catalytic catalysts of composition Ni59Nb40Pt1-xYx (Y=Cu, Ru, x=0.4% at.) have been developed, obtained by mechanical alloying, resulting in higher current densities and an improvement in tolerance to adsorbed CO vs. Ni59Nb40Pt1 catalyst. By using voltammetric techniques, the appearance of three oxidation peaks can be observed. The first peak could be associated with the electrooxidative process of ethanol/bioethanol to acetaldehyde, the second peak could be the oxidation of acetaldehyde to acetic acid, and the last peak might be the final oxidation to CO2. Chrono-amperometric experiments show qualitative poisoning of catalyt...

British Library Electronic Table of Contents (United Kingdom)

Iron nanoparticles were produced using extracts of green tea leaves (GT-Fe NPs). The materials were characterized using TEM, SEM/EDX, XPS, XRD, and FTIR techniques and were shown to contain mainly iron oxide and iron oxohydroxide. The obtained nanoparticles were then utilized as a Fenton-like catalyst for decolorization of aqueous solutions containing methylene blue (MB) and methyl orange (MO) dyes. The related experiments investigated the removal kinetics and the effect of concentration for both MB and MO. The concentrations of dyes in aqueous solution were monitored using ultraviolet-visible (UV-vis) spectroscopy. The results indicated fast removal of the dyes with the kinetic data of MB following a second order removal rate, while those of MO were closer to a first order removal rate. T...

Energy Technology Data Exchange (ETDEWEB)

Catalytic activity of industrial metallic wastes in coal liquefaction was examined in a 100lb/day continuous coal processing development unit. Red mud, a waste material from the aluminium industry, and an electric furnace flue dust containing Ni, Mo, Co and Fe showed a pronounced effect on the conversion of a Kentucky bituminous coal. Coal conversion and oil production increased significantly with the addition of red mud and flue dust. Comparison of the catalytic activity of pyrite, red mud, and flue dust, based on selectivity analysis, showed that red mud was the most desirable disposable catalyst. However, if the primary goal of coal liquefaction is high oil production, irrespective of hydrogen consumption, pyrite is the most active catalyst among those discussed in the paper.

Energy Technology Data Exchange (ETDEWEB)

All of the direct reaction schemes described and the corresponding process schemes are still in an exploratory state. Ethylene by oxidative coupling of methane could become competitive if process schemes are developed with significantly less expenditures for separation of the product from unconverted feed. No encouragement for formaldehyde from methane can be presently derived from the existing knowledge. Liquid-phase oxidation of methane to methanol appears to be attractive but no final judgement is possible at present. Oxidative dehydrogenation of ethylene and propane look promising although further catalyst improvement is required. Acetic acid from ethane and acrylonitrile from propane have a certain potential as an alternative to present technology. The outlook for acrolein and acrylic acid from propane is less favourable; new concepts for catalyst design are necessary. (orig.)

Energy Technology Data Exchange (ETDEWEB)

The cyclic voltammetry indicated that the oxygen reduction reaction (ORR) proceeded by the four-electron pathway mechanism on larger Ag particles (174 nm), and that the ORR proceeded by the four-electron pathway and the two-electron pathway mechanisms on finer Ag particles (4.1 nm), simultaneously. The kinetics towards ORR was measured at a rotating disk electrode (RDE) with Ag/C electrode. The number of exchanged electrons for the ORR was found to be close to four on larger Ag particles (174 nm) and close to three on finer Ag particles (4.1 nm). The zinc-air battery with Ag/C catalysts (25.9 nm) was fabricated and examined. (author)

British Library Electronic Table of Contents (United Kingdom)

The monoanionic bidentate Schiff base, N-(phenolyl)-benzaldimine (HL), has been employed to synthesize a new vanadium(IV) complex of general composition [VO(L)2] (where L = O, N donor of Schiff base). The ligand and complex have been fully characterized by elemental analyses, molar conductance data, FT-IR, 1H- and 13C-NMR, and UV-Vis spectroscopies. Oxidation of alcohols to their corresponding aldehydes and ketones was conducted by this complex catalyst using Oxone as oxidant under biphasic reaction conditions (CH2Cl2/H2O) and tetra-n-butylammonium bromide as phase transfer agent under air at room temperature.

Energy Technology Data Exchange (ETDEWEB)

Possible explanations are given for the observed asymmetry of the analyzing power in several (rho,..pi../sup -/) reactions.

Energy Technology Data Exchange (ETDEWEB)

The costs of establishing a computer-based training program for FFTF reactor operators are analyzed.

British Library Electronic Table of Contents (United Kingdom)

Only 15mol% of l-proline in ethanol proved to be a very efficient catalyst for the one-pot synthesis of a wide variety of highly substituted pyridines at room temperature. The methodology is mild, efficient, high yielding, and the products can be directly recrystallized from hot ethanol.

Energy Technology Data Exchange (ETDEWEB)

The diffusion of alkali vapours in the anode compartment of a DIR-MCFC produces the deactivation of the internal reforming catalyst. Sets of ceramic porous membranes purposed to limit the diffusion have been manufactured by different techniques and the influence of the preparation technique and of the preparative variables on the morphological characteristics of the membranes structures has been studied.

Energy Technology Data Exchange (ETDEWEB)

The present results indicate that maximum selectivity to acrylic acid can be reached over V-P-Zr-O catalysts. When the hydrocarbon concentration is 5.1 vol.% the selectivity is about 30% at quite high paraffin conversion. Conclusively, some explanations to the observed facts can be given. The V-P-O catalyst promotion with lanthanum by means of mechanochemical treatment is distinguished by the additive uniform spreading all over the matrix surface. Such twophase system is highly active in propane conversion (lanthanum oxide) and further oxidation of the desired products. The similar properties are attributed to V-P-Bi-La-O catalyst. Bismuth, tellurium and zirconium additives having clearly defined acidic properties provoke the surface acidity strengthening and make easier desorption of the acidic product (acrylic acid) from the surface lowering its further oxidation. Additionally, since bismuth and zirconium are able to form ...

International Nuclear Information System (INIS)

Structural units of a hydrogen fuel cell whose characteristics are advisable to investigate by different neutron scattering methods are discussed. The results obtained with the use of Bragg diffraction and small-angle neutron scattering from fuel membranes, nanocarbon-platinum catalysts, and Zn_1_-_xCu_xO hydrogen storage systems are presented.

Energy Technology Data Exchange (ETDEWEB)

Single and binary metal molybdates, supported on silica (80 wt% active phase/20 wt% SiO{sub 2}), having the formula AMoO{sub 4}, where A = Ni, Co, Mg, Mn, and/or Zn, and some ternary molybdates having the formula Ni{sub 0.45}Co{sub 0.45}X{sub 0.066}MoO{sub 4}, where X = P, Bi, Fe, Cr, V, and Ce, were investigated for the oxydehydrogenation of propane to propylene. The reaction is catalytic and is first order in propane disappearance, consistent with the abstraction of a methylene hydrogen being the rate limiting step. Propane conversion and yields of propylene produced vary greatly with the choice of the A metal of the molybdate and the surface area of the catalyst. At 560{degrees}C and atmospheric pressure, the highest propane conversion and highest propylene yields are obtained with NiMoO{sub 4}/SiO{sub 2} (16% at 27% conversion), closely followed by Ni{sub 0.5}Co{sub 0.5}MoO{sub 4}/SiO{sub 2}. The molybdenum content of the compositions greatly influences the ...

Energy Technology Data Exchange (ETDEWEB)

This report forms part of a joint study on a PEFC propulsion system for surface ships, summarized in a presentation to this Seminar, entitled {open_quotes}Study on a Polymer Electrolyte Fuel Cell (PEFC) Propulsion System for Surface Ships{close_quotes}, and which envisages application to a 1,500 DWT cargo vessel. The aspect treated here concerns an experiment in reducing by methanation to a level below 10 ppm the CO that is contained to around 1% in reformate gas.

Energy Technology Data Exchange (ETDEWEB)

The catalytic dehydration of methanol to dimethyl ether was investigated for application on-board a methanol fuelled vehicle. Several catalysts have been tested in a fixed bed reactor. Our approach is to develop a small and efficient reactor converting liquid MeOH under pressure and at low reaction temperatures. (author) 2 figs., 5 refs.

British Library Electronic Table of Contents (United Kingdom)

The catalytic performance of alkaline-treated zeolite H-ZSM-5 in the conversion of methanol to gasoline has been studied. After treatment with 0.20M NaOH, the total conversion capacity increased by a factor of 3.3, and the selectivity towards the gasoline fraction increased by a factor of 1.7. Physical characterization indicated the formation of mesopores and improved crystallinity.

Energy Technology Data Exchange (ETDEWEB)

Details of a series of reactions for the production of ethylene glycol using a catalyst of Nafion solid perfluorosulfonic acid resin was detailed. The reactions included the carbonylation of formaldehyde and esterification and then hydrogenation of the product of the carbonylation, glycolic acid. Other preparations included in the work included methyl glycolate, acetylglycolic acid, methyl acetylglycolate, and methyl methoxyacetate.

Environmental Research Database

DescriptionEnzymes are natural catalysts that are used increasingly to replace environmentally harmful chemicals and to achieve better catalytic selectivity during pulp and paper processing. The main objective of this project is to identify novel plant enzymes for deeper understanding of the process of fibre formation and for future improvement of the quality parameters of wood fibres. Specific modification of the fibre characteristics will facilitate their use as raw materials for the current pulp and pap [continued...

Science.gov (United States)

Processes for the hydrogenation of carbon monoxide have had commercial importance since about 1920, when the commercial production of methanol and higher alcohols on oxide catalysts began. Soon thereafter Fischer and Tropsch discovered that liquid hydrocarbons could be synthesized from carbon monoxide and hydrogen over Group VIII metal catalysts. Following extensive catalyst and process development efforts, this technology provided Germany with a source of liquid fuels during World War II. The period following the war saw an acceleration in research and development on the Fischer-Tropsch process, but the only commercial application that was to emerge was the SASOL process in the Union of South Africa. The oil crises of the 1970s have rekindled worldwide interest in indirect liquefaction technologies for the production of clean, high-quality motor fuels from coal. The development of more efficient coal gasification processes ...

Energy Technology Data Exchange (ETDEWEB)

Progress reports are presented for the following two areas: catalytic cracking studies with water-wet silica-alumina catalysts; and Fischer-Tropsch reactor studies where similarities and differences between fixed bed and slurry type reactors are investigated and further experiments conducted to measure mass transfer coefficients and reaction kinetics which are to be used in a model slurry reactor. The following are some of the conclusions. (1) The premise that the presence of liquid water might increase catalytic cracking activity was found to be invalid. It was demonstrated that cracking can occur at previously unobserved low temperatures (though at low conversions) and that an anomaly exists in that one of the catalysts tested shows an entirely different cracking behavior and probably follows a different cracking mechanism. (2) the diameter of a fixed-bed Fischer-Tropsch reactor critically affected the resistance of the reactor to plugging ...

Energy Technology Data Exchange (ETDEWEB)

Most chemical reactions in industry and biology are catalytic and play a role at some stage of the processing of about 80% of the goods manufactured in the U.S., yet catalysis is a neglected subject in chemical education. This book integrates the fragmentary treatment accorded the topic until now. It covers, in a unified way, catalysis in solutions, by enzymes, in synthetic polymers within the molecular scale cages of zeolites and other molecular sieves, and on surfaces of inorganic solids. The central ideas are chemical; and principles are illustrated by emphasizing industrial reactions and catalysts.

Science.gov (United States)

A process is provided for conducting organic compound conversion over a catalyst composition comprising a supported crystalline zeolite having a high initial silica-to-alumina mole ratio, said supported zeolite being prepared by compositing said crystalline zeolite with alumina, reacting the composite with a particular hydrogen fluoride solution in a specified way, drying the hydrogen fluoride reacted composite, treating the dried composite by hydrolysis, ammonolysis and/or by contact with an ammonium salt solution, and calcining the resulting material.

Energy Technology Data Exchange (ETDEWEB)

For the first time in scientific literature, in our joint work with Dr. G. Ladwig in 1978 it was established phase portraite of the oxide vanadium-phosphorus system within wide range of P/V ratios from 0.5 to 3.2. Some later those data were confirmed. By investigation of the properties of individual vanadium-phosphorus phases it was also shown that the active component of such catalysts in n-butane oxidation was vanadyl pyrophosphate phase (VO){sub 2}Pr{sub 2}O{sub 7}. From then the conclusion has been evidenced by numerous publications and at present it has been out of doubt practically all over the world. It was hypothized that the unique properties of (VO){sub 2}P{sub 2}O{sub 7} in the reaction of n-butane oxidation could be explained by the presence of paired vanadyl groups and nearness of the distances between neighbouring vanadyl pairs and that between the first and fourth carbon atoms in n-butane molecule. The molecule activation occured at the latter atoms ...

Energy Technology Data Exchange (ETDEWEB)

This was a university-based research project in support of distributed reforming production technologies for hydrogen. Our objective was to examine the steam reforming of bio-ethanol and other related bio-derived liquids over non-precious metal catalyst systems to enable small-scale distributed hydrogen production technologies from renewable sources. The study targeted development of a catalytic system that does not rely on precious metals and that can be active in the 350-550 C temperature range, with high selectivity and high stability. To this end, we adopted a multi-prong research strategy, that included catalyst formulation and synthesis, detailed catalyst characterization, reaction kinetics and reaction engineering, molecular modeling and economic analysis studies. Our approach was an iterative one, where the knowledge gained in one aspect of the study was utilized to modify and fine-tune catalyst ...

Science.gov (United States)

The phase space beam analyzer is a measurement instrument that is applied in laser technology to perform analyses of the spatial and angular distribution of rays. We are interested in this instrument as a means to characterize non-coherent light sources. In this context, a closer look at the tolerances of this optical instrument was considered useful. Having a so-called quadrupole lens as a key element, the phase space beam analyzer is a device that features anamorphic optical properties. To describe these anamorphic properties, recurrence was made to a description by extended ray-transfer matrices. This formalism allows for an analysis of the alignment tolerances of the phase space beam analyzer and facilitates a study of the sensitivities of the instrument. The analysis is complemented using numerical ray tracing.

Science.gov (United States)

... analyze importance sampling schemes for stochastic networks ... an interesting mixed open/closed queueing network ... with a suitable terminal condition ...

International Nuclear Information System (INIS)

... Authority (Turkey) The Scientific and Technical Research Council of Turkey

Science.gov (United States)

... In 1982 an acousto-optic spectrum analyzer incorporated ... the OPTIMP is the optically controlled optical ... switch that changes the intensity reflectance ...

Science.gov (United States)

... In this paper research aimed at creating a computer vision system to power such an optimal edging and ... ...

Energy Technology Data Exchange (ETDEWEB)

One of the design targets for the ITER Tokamak Exhaust Processing system is not to lose more than 10{sup -5} g h{sup -1} into the Normal Vent Detritiation System of the Tritium Plant. The plasma exhaust gas, therefore, needs to be processed in a way that an overall tritium removal efficiency of about 10{sup 8} is reached. Such a high decontamination factor can only be achieved by multistage processes. The third step of the three step CAPER process developed at the TLK is based on a so-called permeator catalyst (PERMCAT) reactor, a direct combination of a Pd/Ag permeation membrane and a catalyst bed. The PERMCAT principle is based on isotopic swamping in a counter current mode. Previous tritium experiments employing laboratory scale PERMCAT reactors have revealed decontamination factors as high as 10{sup 5} for the third CAPER step. First tritium tests with a technical scale PERMCAT reactor led to similar decontamination factors and clearly ...

Science.gov (United States)

The investigation of various Two-Stage Liquefaction (TSL) process configurations was conducted at the Wilsonville Advanced Coal Liquefaction R D Facility between July 1982 and September 1986. The facility combines three process units. There are the liquefaction unit, either thermal (TLU) or catalytic, for the dissolution of coal, the Critical Solvent Deashing unit (CSD) for the separation of ash and undissolved coal, and a catalytic hydrogenation unit (HTR) for product upgrading and recycle process solvent replenishment. The various TSL process configurations were created by changing the process sequence of these three units and by recycling hydrotreated solvents between the units. This report presents a description of the TSL configurations investigated and an analysis of the operating and performance data from the period of study. Illinois No. 6 Burning Star Mine coal Wyodak Clovis Point Mine coal were processed. Cobalt-molybdenum and disposable iron-oxide ...

Energy Technology Data Exchange (ETDEWEB)

The knowledge shown in this work of the relationships between the oxidation stage of chromium, molybdenum and tungsten and their catalytic activity in some hydrocarbon reactions was achieved by the combination of separate investigations of reduction properties and the catalytic activity of the catalysts concerned. To characterize the electronic state of the reduced surfaces, X-ray photo-electronic spectroscopy was mainly used, supplemented by electron spin resonance. The catalyst activity was measured in conventional apparatus (flow, pulse and gradient-free reactors). (orig.) [Deutsch] Die in dieser Arbeit dargestellten Erkenntnisse ueber die Zusammenhaenge zwischen der Oxidationsstufe von Chrom, Molybdaen und Wolfram und ihrer katalytischen Aktivitaet in einigen Kohlenwasserstoffreaktionen wurden durch die Kombination getrennter Untersuchungen ueber Reduktionseigenschaften und katalytische Aktivitaet der betreffenden Katalysatoren erzielt. ...

Science.gov (United States)

Certain materials, especially Sn, passivate the rare earth-exchanged Y zeolite (REY) used in petrochemical fluid-cracking catalysts against vanadium degradation caused by V impurities in the feed oil. The mechanism of passivation was investigated here from the standpoint of high-temperature oxide acid-base reaction; i.e., where the controlling factors were considered to be Lewis acid-base reactions between V{sub 2}O{sub 5}, the RE oxides, SnO{sub 2}, etc. Molten salt tests at 680{degree}C showed SnO{sub 2}, presumably because of its acidic nature, to be essentially nonreactive with V{sub 2}O{sub 5} or Na{sub 2}O-V{sub 2}O{sub 5} compounds. A hypothesis was developed to explain how the passivation effect by Sn might result from the unique resistivity of SnO{sub 2} to reaction with V{sub 2}O{sub 5}.

International Nuclear Information System (INIS)

This paper reports on the superiority of zeolites over amorphous solids which is well documented for solid acid catalysts of industrial use. Crystalline supports, likewise, open attractive perspectives for catalysis by metals, alloys, and ligated metal clusters. Size and location of clusters can be controlled by careful design of the preparation conditions. Pore dimensions control the access of reactants to active sites and escape paths for products. Cage dimensions determine which transition states can be attained; window apertures are functional in isolating metal clusters from each other, thus preventing ther coalescence and growth. The ship-in-a-bottle method permits deisgn of fairly large active complexes entrapped in zeolite cages. Orientation of non-spherical molecules in a zeolite proe helps to direct their collision with a metal particle to the head on mode; however, isolated Pt atoms hidden in niches of the pore walls can attack passing molecules at their ...

Energy Technology Data Exchange (ETDEWEB)

Nine coals from Spanish, British, German and American mining basins were hydrogenated using Fe catalyst precursors (red mud and FeSO{sub 4}), without solvent at 300, 350, and 400 {degree}C and 10 MPa of H{sub 2}. Overall conversion and product distribution are related to the textural characteristics of the original coals and are studies throughout the distinct hydrogenation processes. Results reveal that with FeSO{sub 4} as a catalyst precursor, conversions increase with coal surface area. However, when red mud (RM) is used, conversions are independent of coal textural characteristics. Higher conversions are obtained with FeSO{sub 4} than with RM at 300 and 350 {degree}C whereas at 400 {degree}C higher conversions are obtained with RM. This different catalytic activity is also reflected in the changes of the textural characteristics observed in each case. Up to 350 {degree}C, the residues from FeSO{sub 4}-catalyzed processes reveal increased ...

Energy Technology Data Exchange (ETDEWEB)

In the past three years, we followed the work plan as we suggested in the proposal and made every efforts to fulfill the project objectives. Based on our large amount of creative and productive work, including both of experimental and theoretic aspects, we received important technical breakthrough on naphthenic acid removal process and obtained deep insight on catalytic decarboxylation chemistry. In detail, we established an integrated methodology to serve for all of the experimental and theoretical work. Our experimental investigation results in discovery of four type effective catalysts to the reaction of decarboxylation of model carboxylic acid compounds. The adsorption experiment revealed the effectiveness of several solid materials to naphthenic acid adsorption and acidity reduction of crude oil, which can be either natural minerals or synthesized materials. The test with crude oil also received promising results, which can be potentially developed into a ...

Science.gov (United States)

During this reporting period four direct coal liquefaction experiments have been completed and a fifth is underway. These experiments have produced conversion and selectivity data on samples of Utah coal slurried in tetralin and catalyzed using iron-titanium hydride. Hydrogen loading of the alloy, catalyst particle size, coal particle size, operating temperatures for alloy addition and liquefaction without the catalysts present, have all been studied during these four experiments. Conversions of 61% DAF in 30 min have been recorded at 485/sup 0/F and 520 psia. The fifth run using the same coal at a reduced particle size has begun, after which we will move to samples of Kentucky and Alabama coals. Equipment manufacture, delivery, and installation delays, totaling over 6 months, greatly reduced the time available for research, making a 6 month no cost extension necessary. The extended time will permit completion of the proposed research tasks. 4 ...

Energy Technology Data Exchange (ETDEWEB)

For the removal and recycle of CO2, a global warming gas, utilization of photosynthesis by micro algae is investigated. Formed micro algae are decomposed into CO2, H2O and CH4 again, which does not result in the permanent fixation. For the effective utilization of these micro algae, creation of petroleum alternate energy was tried through the co-liquefaction of micro algae with coal. Were investigated influences of the reaction temperature during the co-liquefaction and influences of catalysts, such as Fe(CO)5-S, Ru(CO)12, and Mo(CO)6-S, which are effective for the coal liquefaction. Micro algae, such as chlorella, spirulina, and littorale, and Yallourn brown coal were tested. It was found that co-liquefaction of micro algae with coal can be successfully proceeded under the same conditions as the liquefaction of coal. The oil yield obtained from the co-liquefaction in the presence of Fe(CO)5-S, an effective catalyst for coal liquefaction, ...

Energy Technology Data Exchange (ETDEWEB)

This report presents the results of Run 260 performed at the Advanced Coal Liquefaction R&D Facility in Wilsonville. The run was started on July 17, 1990 and continued until November 14, 1990, operating in the Close-Coupled Integrated Two-Stage Liquefaction mode processing Black Thunder mine subbituminous coal (Wyodak-Anderson seam from Wyoming Powder River Basin). Both thermal/catalytic and catalytic/thermal tests were performed to determine the methods for reducing solids buildup in a subbituminous coal operation, and to improve product yields. A new, smaller interstage separator was tested to reduce solids buildup by increasing the slurry space velocity in the separator. In order to obtain improved coal and resid conversions (compared to Run 258) full-volume thermal reactor and 3/4-volume catalytic reactor were used. Shell 324 catalyst, 1/16 in. cylindrical extrudate, at a replacement rate of 3 lb/ton of MF coal was used in the catalytic stage. Iron oxide ...

Energy Technology Data Exchange (ETDEWEB)

The investigations showed that the new adsorber/catalyst composites are well suited for chemical degradation of persistent water pollutants. Compared with alternative processes, the reaction selectivity and the consumption of oxidant are more favourable as the reaction now takes place on/inside the solid. The process, which was developed originally for purification of contaminated water, can be transferred to many other systems of materials. For example, it is expected that the soot emissions of diesel engines will be reduced significantly after efficient hydrogenation of the aromatics contained in the diesel engine on molybdenum-charged mesoporous composites. [German] Mit den vorliegenden Untersuchungen konnte ein erster Nachweis gefuehrt werden, dass die neu entwickelten Adsorber/Katalysator-Komposite fuer den chemischen Abbau persistenter Wasserschadstoffe geeignet sind. Im Vergleich zu alternativen Verfahrensloesungen kann die Selektivitaet der Reaktion und der ...

Energy Technology Data Exchange (ETDEWEB)

Research activity during the 1991--1992 funding period has been concerned with the following topics relevant to carbon monoxide activation. (1) Exploratory studies of water gas shift catalysts heterogenized on polystyrene based polymers. (2) Mechanistic investigation of the nucleophilic activation of CO in metal carbonyl clusters. (3) Application of fast reaction techniques to prepare and to investigate reactive organometallic intermediates relevant to the activation of hydrocarbons toward carbonylation and to the formation of carbon-carbon bonds via the migratory insertion of CO into metal alkyl bonds.

Energy Technology Data Exchange (ETDEWEB)

The methods of diffuse-reflection optical spectroscopy and EPR were used to study the state of molybdenum in catalysts prepared by impregnating ultrastable zeolite with molybdenum salt solutions and by mixing in the solid phase with MoCl/sub 5/. It has been shown that molybdenum introduced into zeolites in small amounts is found basically in the form of isolated hexavalent ions of molybdenum. In addition, Mo/sup 5 +/ and Mo/sup 4 +/ ions are also present. Heteropolycompounds also form. The molybdenum ions are most readily reduced in the zeolite prepared by impregnation with a solution of ammonium paramolybdate.

Science.gov (United States)

According to W. H. Wiser and A. G. Oblad, the program at the University of Utah to develop coal conversion techniques, which has received federal grants of $1.35 million since 1969, recently was awarded $425,000 from the U.S. Office of Coal Research for the development of catalysts for coal conversion and low-sulfur fuel oil production. In tests, 100 lb of coal have been converted into 95 lb of products composed of 30 lb liquid fuel like gasoline, 5 lb of diesel or fuel oil, 30 lb of gaseous fuel, and 30 lb of char.

International Nuclear Information System (INIS)

The method of programmed thermodesorption has been used to study the forms of hydrogen adsorption in ZrNiHsub(x) hydride. It is shown that high concentration of the hydrogen, which extracted from hydride in the temperature range of 240-260 deg C results in appearance of ''reverse'' peak. Charge of hydride adsorption properties during its oxidation-reduction treatment is studied. Comparison with spectra of hydrogen thermodesorption from the surface of Ni/ZrO_2 deposited catalyst and zirconium oxide is carried out.

British Library Electronic Table of Contents (United Kingdom)

Doped ultrafine silicon dioxide powder with a narrow particle size distribution was obtained by RF discharge-stimulated dichlorosilane (SiH2C) oxidation at a low pressure using isobutylene as the combustion inhibitor and chromium hexacarbonyl (Cr(CO)6) as the dopant. The formation and morphology of the ultrafine particles are governed by the parameters of the RF discharge and by the chemical mechanism of the combustion reaction yielding the aerosol. Submicron-sized filamentous carbon structures can be obtained by isobutylene decomposition under spark discharge conditions in the presence of a molybdenum metal catalyst.

Energy Technology Data Exchange (ETDEWEB)

Zeolite Y is the active component of most commercial cracking catalysts. Interaction of H[sub 3]PO[sub 4] with extraframework aluminum of ultra-stable zeolite (USY) leads to the formation of different types of aluminum phosphates, while there is no indication of the formation of SAPO zeotype structures. The total acidity of USY slightly decreases upon the H[sub 3]PO[sub 4] treatment, while the maximum in the distribution of acid strength is shifted to milder acidities. Dealumination of the zeolite and creation of POH sites associated with AIPO[sub 4] are responsible for the modifications observed. 37 refs., 8 figs., 3 tabs.

Energy Technology Data Exchange (ETDEWEB)

In order to improve the handling capability of red mud, it is mixed with fine-grain coal material such as brown coal or lignite in dust form, in a ratio by weight of between 0.5-10:1. The liquid present in the red mud is bound by the very fine coal admixed therewith so that the resulting mixture can be stored in a silo and even pneumatically conveyed, and the oily properties of the red mud are removed by the treatment. The mixture is particularly suitable for use in connection with the hydrogenating liquefaction of coal in which the red mud is used as a catalyst.

Energy Technology Data Exchange (ETDEWEB)

Scientists of the Institute of Wood Chemistry of the Latvian Academy of Sciences have developed two highly efficient processes for producing furfural, a feedstock for varnishes, synthetic resins and plastics. It is made of production wastes, including branches and small-dimension timber. By one process, the raw material is chipped, treated first with diluted sulphuric acid and then with steam heated to 250 degrees C. The other uses concentrated sulphuric acid as a catalyst. Besides furfural, this process also yields sugar solutions used in alcohol and nutrient yeast production.

Science.gov (United States)

We have investigated the stability and catalytic activity of epitaxial overlayers of rhodium on Au(111) and Pd(111). Both surfaces show a strong affinity for hydrogen. We have calculated the energy of adsorption both for a strongly and a more weakly adsorbed species; the latter is the intermediate in the hydrogen evolution reaction. Both the energy of activation for hydrogen adsorption (Volmer reaction) and hydrogen recombination (Tafel reaction) are very low, suggesting that these overlayers are excellent catalysts. PMID:21847482

Energy Technology Data Exchange (ETDEWEB)

The Balandin type volcano plots have been considered for the main criterion both in catalysis and electrocatalysis to estimate their fundamental properties and optimal activity: ({alpha}) The ones, when some physical feature or catalytic activity itself is plotted usually along transition series, and ({beta}) The others, when catalytic activity arises as a function of some energetic property, the most usually of the adsorption enthalpy of intermediates bonding upon the substrate in the rate determining step (rds). 29 refs.

Science.gov (United States)

Results of research programs in coal liquefaction are presented. Areas of research include: desulfurization by bioprocessing; characterization of coal liquefaction processes by XAFS spectroscopy; coprocessing of coal with heavy oil and petroleum residuals; liquefaction research in pyrolysis, catalysis and coal dissolution; novel catalysts; data base development; resource evaluation; depolymerization; solvent extraction and chromatography; correlations of liquefaction yields and coal structure. Individual projects are processed separately for the data bases. (CBS)

Energy Technology Data Exchange (ETDEWEB)

The performance of a solar chemical heat pipe was studied using CO{sub 2}reforming of methane as the endothermic reaction. A directly heated vertical reactor, packed with a rhodium catalyst was used. The solar tests were carried out in the Schaeffer solar furnace of the Weizmann Institute of Science. The power absorbed was up to 6.3 KW, the maximal flow rates of the gases reached 11,000 1/h, and the methane conversions reached 85%. A computer model was developed to simulate the process. Agreement of the calculations with the experimental results was quite satisfactory.

Science.gov (United States)

Research programs on coal and coal liquefaction are presented. Topics discussed are: coal science, combustion, kinetics, surface science; advanced technology projects in liquefaction; two stage liquefaction and direct liquefaction; catalysts of liquefaction; Fischer-Tropsch synthesis and thermodynamics; alternative fuels utilization; coal preparation; biodegradation; advanced combustion technology; flue gas cleanup; environmental coordination, and technology transfer. Individual projects are processed separately for the data base. (CBS)

Energy Technology Data Exchange (ETDEWEB)

Hydrocarbon synthesis during CO hydrogenation over Pd/M-ZSM5 (M=H,Na,La) and Pd/SiO/sub 2/ has been investigated. Overall activity depended on the cation-exchanged form of the support and decreased in the order Pd/La-ZSM5 = Pd/Na-ZSM5 > Pd/H-ZSM5 > Pd/SiO/sub 2/. The zeolite-supported catalysts showed high selectivity towards saturated C/sub 2/-C/sub 6/ hydrocarbons, whereas Pd/SiO/sub 2/ favored methanol production. Increasing temperature and H/sub 2//CO feed ratio led to higher reaction rates, lower yields of C/sub 2/-C/sub 6/ products, and increased lighter hydrocarbons. A mechanical mixture of Pd/SiO/sub 2/ and Na-ZSM5 showed similar product distribution as Pd/Na-ZSM5. Infrared spectra of the catalysts under reaction conditions indicate the presence of adsorbed oxygenates on the zeolite. Changes in the IR bands during the initial stages of the reaction suggest that surface species on the zeolite are not methanol synthesis ...

Energy Technology Data Exchange (ETDEWEB)

Rhodium (Rh) is a critical component of current automotive three-way catalysts (TWCs), particularly with regard to NO{sub x} and CO conversion at rich and stoichiometric air-fuel ratios (A/F). Rh supported on CeO{sub 2} was active for NO{sub x} and CO conversions but could be deactivated easily by high temperature aging. The cause of the deactivation is ascribed to the sintering of CeO{sub 2}. ZrO{sub 2} incorporation into CeO{sub 2} is reported to have high thermal durability in terms of oxygen storage capacity (OSC). There has been no report showing direct experimental evidence that Rh-loaded on CeO{sub 2}-ZrO{sub 2} mixed oxides induced effects on TWC performance improvement in the actual automotive exhaust. In the present paper, the Rh-CeO{sub 2} interaction contributing to NO{sub x} reduction and the catalytic behavior of Rh-loaded CeO{sub 2}-ZrO{sub 2} mixed oxide is addressed. Incorporating CeO{sub 2}-ZrO{sub 2} into a catalyst offered ...

International Nuclear Information System (INIS)

An energy analyzer has been constructed and operated in UHV for the purpose of analyzing the energy of neutral atoms scattered from solid surfaces. The analyzer consists of a LiF single crystal located at an angle close to the normal to the sample crystal so that the diffraction pattern obtained by scanning the LiF crystal yields the energy of the scattered atoms. Two designs which have been used are described. The temperature of both sample and analyzer crystal is near 20 K and once cleaned they can be maintained in the state of initial preparation for many weeks. The sample was a (001) Cu surface in this case. Such an energy analyzer can only be used, in most cases, for He atom scattering although Ne atoms could be used if the scattered intensities were adequate. The detector developed in this study is able to detect about 2 x 10"5 atoms/s. The resolution of the spectrometer ...

International Nuclear Information System (INIS)

A historical background is first given in which the role of biomass is described in relation to its competition with fossil biomass for the production of chemicals and energy. Occurrences of reserves from both sources are then compared. Petrochemical and biomass routes are then analyzed in terms of their relative competitive advantages. The oleochemical and biotechnology cases are analyzed in more detail as examples of biomass utilization. Latin American examples of industrial manufacturing of biomass derived chemicals are then provided. Alcochemicals are analyzed in detail as well as essential oils and other chemicals. Finally, references are made to regional Latin American initiatives regarding biomass and the objectives, organization and nature of the initiative are presented.

UK PubMed Central (United Kingdom)

AIM: To analyze the contribution of Orvosi Hetilap (Hungarian Medical Journal) to the field of gastroenterology.METHODS: All issues of the journal between 1857 and 2008 and identified...Full Text Available

International Nuclear Information System (INIS)

Experimental data on high energy cumulative particle production are analyzed in the frame of flucton models. The performed analysis evidence for the flucton as a multiquark system with high baryon dnsity.

Science.gov (United States)

... Those functions are fundamental routines to build a power model for more complex circuits or functional blocks. ... 21 of 54 6. Memory Power Model ...

Energy Technology Data Exchange (ETDEWEB)

Stochastic models for the simulation of global radiation are discussed. Thermal transients in the ground are analyzed. The performance of buried-pipe storage and a space heating system with long-term storage is described.

Energy Technology Data Exchange (ETDEWEB)

A headspace gas chromatographic (GC) method, which can be automated, has been developed for determination of methyl bromide. This method has been applied to wheat, flour, cocoa, and peanuts. Samples to be analyzed are placed in headspace sample vials, water is added, and the vials are sealed with Teflon-lined septa. After an appropriate equilibration time at 32 degrees C, the samples are analyzed within 10 h. A sample of the headspace is withdrawn and analyzed on a gas chromatograph equipped with an electron capture detector (ECD). Methyl bromide levels were quantitated by comparison of peak area with a standard. The standard was generated by adding a known amount of methyl bromide to a portion of the matrix being analyzed and which was known to be methyl bromide free. The detection limit of the method was 0.4 ppb. The coefficient of variation (CV) was 6.5% for wheat, 8.3% for flour, 3.3% for cocoa, and ...

International Nuclear Information System (INIS)

The possibility of gamma-absorption identification of the analyzed substance is considered. the basic provisions of the proposed method are concentrated on the example of carbohydrates and hydrocarbons. The above method is tested experimentally on polyethylenes and polystyrene

UK PubMed Central (United Kingdom)

Given growing interest in Functional Data Analysis (FDA) as a useful method for analyzing human movement data, it is critical to understand the effects of standard FDA procedures, including...Full Text Available

Science.gov (United States)

This data set consists of land derived from high resolution imagery and was analyzed according to the Coastal Change ... ...

Science.gov (United States)

This data set consists of land derived from high resolution imagery and was analyzed according to the Coastal Change ... ...

UK PubMed Central (United Kingdom)

Cyanobacteria have become a major model system for analyzing clock phenomena. The temporal program in this organism enhances fitness in rhythmic environments and is truly global—essentially...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

This CD-ROM contains 34 contributions which were held on the 36th MPA seminar 2010 in Stuttgart (Germany). 32 contributions are separately analyzed for the ETDE database.

Energy Technology Data Exchange (ETDEWEB)

The zinc-air battery/fuel cell is an old technology invented one hundred years ago. However, there is renewed interest in this technology in response to the growing need for clean energy technology. The zinc-air battery/fuel cell is more attractive than similar technologies because its characteristics include high power density, safe operation and storage, and low cost. Zinc-air battery/fuel cells can be made in milliwatts to mega watts to accommodate different applications. The zinc-air battery/fuel cell has four major designs, namely primary, mechanically rechargeable, continuous feed and electrically rechargeable zinc-air battery/fuel cells. Among the different designs, the most common is the air cathode. There are 3 generations of catalysts used in the air cathodes. This paper discussed the different designs of the zinc-air battery/fuel cell, and more specifically, the air cathode structure and performance.

Energy Technology Data Exchange (ETDEWEB)

Coal can be converted to liquid fuels via three generically defined technologies: pyrolysis, direct hydroliquefaction, and indirect liquefaction. This paper presents a general overview of the indirect liquefaction technology and a discussion of processes tht are commercially available as well as those in the development stage. Finally, the objective of the DOE research and development program in conversion of synthesis gas derived from coal to transportation fuels is summarized. The current outlook for indirect liquefaction is encouraging. New facilities are being built in South Africe and New Zealand, and commercial plants could be designed and built for operation in the United States using proven technology. At the same time, developments in gasification as well as liquefaction catalysts and reactor technology promise significant improvements in indirect liquefaction processes in the years to come.

Energy Technology Data Exchange (ETDEWEB)

We prepared cathodes with various types of activated carbon and measured the cathodes' electrochemical performance according to the kind of activated carbon. Activated carbon supplies airflow channels and reaction sites in the cathode of zinc air batteries. When we use activated carbon with a high specific surface area as the cathode's catalyst substrate, we expect high electrochemical performance because this type of carbon provides more air flow channels and reaction sites. We focused on investigating the relationship between the cathode's pore structure and its electrochemical characterizations. We also studied the effects of the various activated carbon materials on the zinc air batteries' performance. Increasing the macropores or mesopores in the activated carbon resulted in achieving more power from the battery. (author)

Energy Technology Data Exchange (ETDEWEB)

The morphology and size characteristics of the population of AlP particles produced by treatment of a pure aluminium melt with an Al-Fe-P inoculant addition have been determined. The particles are shown to be polyhedral like the primary silicon they nucleate in hypereutectic Al-Si alloy melts and to be prone to clustering at increased phosphorus addition levels. The number of AlP particles per unit area is shown to be comparable with the corresponding number density of polyhedral primary silicon in Al-20 wt.% Si treated in the same way under identical conditions which is consistent with earlier conclusions that AlP acts as a nucleation catalyst for primary silicon in hypereutectic Al-Si casting alloys. (orig.)

Energy Technology Data Exchange (ETDEWEB)

Sasol, a South-African company, has converted coal into synthetic fuels for 40 years; in order to increase by 6 pc its annual production (40 Mt coal are processed), Sasol has launched the Sky High project and intends to replace the ancient Sasol Synthol reactors by Advanced Synthol reactors using conventional fluidized beds instead of circulating fluidized beds. Coal is first gasified under high pressure and high temperature conditions (the Secunda site uses the Fischer-Tropsch conversion process) and is then processed in the reactor through a single phase process using an iron-base catalyst, leading to significant cost reductions.

Energy Technology Data Exchange (ETDEWEB)

Neopentane, because of its unique structural features, was found to be a useful probe for the assay of the acidity of various zeolites. The C-C bond was attacked by catalyst protons yielding CH/sub 4/ and the isobutyl carbenium ion in equal quantities. The latter either decomposed to produce isobutene or underwent secondary reactions. New avenues for reaction were opened with isobutane. The reaction of the Bronsted protons with the tertiary CH bonds produced H/sub 2/ and the same isobutyl carbenium ion. Hydride ion transfer of the same tertiary hydrogen to existing carbenium ions also occurred and the results showed that about half of the reaction was carried by this pathway. As with Neopentane, the C-C bond could also be attacked yielding the sec-propyl carbenium ion. These tools are being further developed.

Energy Technology Data Exchange (ETDEWEB)

An experimental and modelling study was performed for a reverse flow catalytic converter attached to a natural gas/diesel dual fuel engine. The catalytic converter had a segmented ceramic monolith honeycomb substrate and a catalytic washcoat containing a predominantly palladium catalyst. A one-dimensional single channel model was used to simulate the operation of the converter. The kinetics of the CO and methane oxidation followed first-order behaviour. The activation energy for the oxidation of methane showed a change with temperature, dropping from a value of 129 to 35 kJ/mol at a temperature of 874 K. The reverse flow converter was able to achieve high reactor temperature under conditions of low inlet gas temperature, provided that the initial reactor temperature was sufficiently high. (author)