hydrocarbon conversion reactions: Topics by WorldWideScience.org

Sample records for hydrocarbon conversion reactions

Conversion of hydrocarbon oils into motor fuels

Energy Technology Data Exchange (ETDEWEB)

1937-11-09

The abstract describes a process for producing lower boiling hydrocarbon motor fuels with a starting material of wide boiling range composed primarily of hydrocarbon oils boiling substantially above the boiling range of the desired product. Separate catalytic and pyrolytic conversion zones are simultaneously maintained in an interdependent relationship. Higher boiling constituents are separated from residual constituents by fractionation while desirable reaction conditions are maintained. All or at least a portion of the products from the catalytic and pyrolytic conversion zones are blended to yield the desired lower boiling hydrocarbons or motor fuels.
First principles modeling of hydrocarbons conversion in non-equilibrium plasma

Energy Technology Data Exchange (ETDEWEB)

Deminsky, M.A.; Strelkova, M.I.; Durov, S.G.; Jivotov, V.K.; Rusanov, V.D.; Potapkin, B.V. [Russian Research Centre Kurchatov Inst., Moscow (Russian Federation)

2001-07-01

Theoretical justification of catalytic activity of non-equilibrium plasma in hydrocarbons conversion process is presented in this paper. The detailed model of highest hydrocarbons conversion includes the gas-phase reactions, chemistry of the growth of polycyclic aromatic hydrocarbons (PAHs), precursor of soot particles formation, neutral, charged clusters and soot particle formation, ion-molecular gas-phase and heterogeneous chemistry. The results of theoretical analysis are compared with experimental results. (authors)
Methods for natural gas and heavy hydrocarbon co-conversion

Science.gov (United States)

Kong, Peter C [Idaho Falls, ID; Nelson, Lee O [Idaho Falls, ID; Detering, Brent A [Idaho Falls, ID

2009-02-24

A reactor for reactive co-conversion of heavy hydrocarbons and hydrocarbon gases and includes a dielectric barrier discharge plasma cell having a pair of electrodes separated by a dielectric material and passageway therebetween. An inlet is provided for feeding heavy hydrocarbons and other reactive materials to the passageway of the discharge plasma cell, and an outlet is provided for discharging reaction products from the reactor. A packed bed catalyst may optionally be used in the reactor to increase efficiency of conversion. The reactor can be modified to allow use of a variety of light sources for providing ultraviolet light within the discharge plasma cell. Methods for upgrading heavy hydrocarbons are also disclosed.
Formalization of hydrocarbon conversion scheme of catalytic cracking for mathematical model development

Science.gov (United States)

Nazarova, G.; Ivashkina, E.; Ivanchina, E.; Kiseleva, S.; Stebeneva, V.

2015-11-01

The issue of improving the energy and resource efficiency of advanced petroleum processing can be solved by the development of adequate mathematical model based on physical and chemical regularities of process reactions with a high predictive potential in the advanced petroleum refining. In this work, the development of formalized hydrocarbon conversion scheme of catalytic cracking was performed using thermodynamic parameters of reaction defined by the Density Functional Theory. The list of reaction was compiled according to the results of feedstock structural-group composition definition, which was done by the n-d-m-method, the Hazelvuda method, qualitative composition of feedstock defined by gas chromatography-mass spectrometry and individual composition of catalytic cracking gasoline fraction. Formalized hydrocarbon conversion scheme of catalytic cracking will become the basis for the development of the catalytic cracking kinetic model.
Conversion of Methane to C2 Hydrocarbons and Hydrogen Using a Gliding Arc Reactor

International Nuclear Information System (INIS)

Hu Shuanghui; Wang Baowei; Lv Yijun; Yan Wenjuan

2013-01-01

Methane conversion has been studied using gliding arc plasma in the presence of argon. The process was conducted at atmospheric pressure and ambient temperature. The focus of this research was to develop a process of converting methane to C 2 hydrocarbons and hydrogen. The main parameters, including the CH 4 /Ar mole ratio, the CH 4 flow rate, the input voltage, and the minimum electrode gap, were varied to investigate their effects on methane conversion rate, product distribution, energy consumption, carbon deposit, and reaction stability. The specific energy requirement (SER) was used to express the energy utilization efficiency of the process and provided a practical guidance for optimizing reaction conditions for improving energy efficiency. It was found that the carbon deposition was not conducive to methane conversion, and the gliding arc plasma discharge reached a stable state twelve minutes later. Optimum conditions for methane conversion were suggested. The maximum methane conversion rate of 43.39% was obtained under the optimum conditions. Also, C 2 hydrocarbons selectivity, C 2 hydrocarbons yield, H 2 selectivity, H 2 yield and SER were 87.20%, 37.83%, 81.28%, 35.27%, and 2.09 MJ/mol, respectively.
Halogen-Mediated Conversion of Hydrocarbons to Commodities.

Science.gov (United States)

Lin, Ronghe; Amrute, Amol P; Pérez-Ramírez, Javier

2017-03-08

Halogen chemistry plays a central role in the industrial manufacture of various important chemicals, pharmaceuticals, and polymers. It involves the reaction of halogens or halides with hydrocarbons, leading to intermediate compounds which are readily converted to valuable commodities. These transformations, predominantly mediated by heterogeneous catalysts, have long been successfully applied in the production of polymers. Recent discoveries of abundant conventional and unconventional natural gas reserves have revitalized strong interest in these processes as the most cost-effective gas-to-liquid technologies. This review provides an in-depth analysis of the fundamental understanding and applied relevance of halogen chemistry in polymer industries (polyvinyl chloride, polyurethanes, and polycarbonates) and in the activation of light hydrocarbons. The reactions of particular interest include halogenation and oxyhalogenation of alkanes and alkenes, dehydrogenation of alkanes, conversion of alkyl halides, and oxidation of hydrogen halides, with emphasis on the catalyst, reactor, and process design. Perspectives on the challenges and directions for future development in this exciting field are provided.
Oxygen-containing coke species in zeolite-catalyzed conversion of methanol to hydrocarbons

KAUST Repository

Liu, Zhaohui; Dong, Xinglong; Liu, Xin; Han, Yu

2016-01-01

Zeolites are the most commonly used catalysts for methanol-to-hydrocarbon (MTH) conversion. Here, we identified two oxygen-containing compounds as coke species in zeolite catalysts after MTH reactions. We investigated the possible influences
On energetics of hydrocarbon chemical reactions by ionizing irradiation

International Nuclear Information System (INIS)

Zaykin, Yu.A.; Zaykina, R.F.; Mirkin, G.

2002-01-01

Complete text of publication follows. The present global energy crisis requires the industry to look for technologies that are more effective and, particularly, less energy consuming. The hydrocarbon processing technology based on the electron radiation-induced thermal chemical conversion has a great potential. Comparing the presently predominant thermocatalytic processing, it is much more energy efficient, because chemical conversions go at a minimal processing temperature and pressure. To compare energy consumption by electron irradiation with thermal and thermocatalytic technologies of hydrocarbon processing one must see major differences between them. While traditional thermocatalytic processes are equilibrium and their energetics can be evaluated based on principles of classic thermodynamics, HEET processing is non-equilibrium and this evaluation approach is not valid for it. However, a theoretical description of radiation-chemical conversion using reaction rate constants determined in thermally equilibrium systems is approximately adequate to radiation processes by substituting equilibrium concentrations of reacting particles as their non-equilibrium concentrations under irradiation. In particular, description of radical reactions initiated by radiation requires substitution of thermally equilibrium radical concentration by much higher concentration defined by the dynamic equilibrium of radical radiation generation and their recombination. The paper presents the comparative analysis of energy consumption in different stages of hydrocarbon processing using classic thermal cracking by heating versus radiation induced cracking. It is shown that in the most energy-consuming stage of processing - the chain reaction initiation necessary for concentration of active radicals, irradiation processing has the great advantage compared to thermal cracking by heating and allows cutting down the total energy consumption by approximately 40%
Catalyst for hydrocarbon conversion

International Nuclear Information System (INIS)

Duhaut, P.; Miquel, J.

1975-01-01

A description is given for a catalyst and process for hydrocarbon conversions, e.g., reforming. The catalyst contains an alumina carrier, platinum, iridium, at least one metal selected from uranium, vanadium, and gallium, and optionally halogen in the form of metal halide of one of the aforesaid components. (U.S.)
Conversion of oligomeric starch, cellulose, or sugars to hydrocarbons

Energy Technology Data Exchange (ETDEWEB)

Silks, Louis A.; Sutton, Andrew; Kim, Jin Kyung; Gordon, John Cameron; Wu, Ruilian; Kimball, David B.

2016-10-18

The present invention is directed to the one step selective conversion of starch, cellulose, or glucose to molecules containing 7 to 26 contiguous carbon atoms. The invention is also directed to the conversion of those intermediates to saturated hydrocarbons. Such saturated hydrocarbons are useful as, for example, fuels.
Oxygen-containing coke species in zeolite-catalyzed conversion of methanol to hydrocarbons

KAUST Repository

Liu, Zhaohui

2016-10-06

Zeolites are the most commonly used catalysts for methanol-to-hydrocarbon (MTH) conversion. Here, we identified two oxygen-containing compounds as coke species in zeolite catalysts after MTH reactions. We investigated the possible influences of the oxygen-containing compounds on coke formation, catalyst deactivation, product selectivity, and the induction period of the MTH reaction through a series of controlled experiments in which one of the identified compounds (2,3-dimethyl-2-cyclopenten-1-one) was co-fed with methanol over a zeolite H-ZSM-5 catalyst. Our results allow us to infer that once produced, the oxygen-containing compounds block the Brønsted acid sites by strong chemisorption and their rapid conversion to aromatics expedites the formation of coke and thus the deactivation of the catalyst. A minor effect of the production of such compounds during the MTH reaction is that the aromatic-based catalytic cycle can be slightly promoted to give higher selectivity to ethylene.
Using Ionic Liquids in Selective Hydrocarbon Conversion Processes

Energy Technology Data Exchange (ETDEWEB)

Tang, Yongchun; Periana, Roy; Chen, Weiqun; van Duin, Adri; Nielsen, Robert; Shuler, Patrick; Ma, Qisheng; Blanco, Mario; Li, Zaiwei; Oxgaard, Jonas; Cheng, Jihong; Cheung, Sam; Pudar, Sanja

2009-09-28

This is the Final Report of the five-year project Using Ionic Liquids in Selective Hydrocarbon Conversion Processes (DE-FC36-04GO14276, July 1, 2004- June 30, 2009), in which we present our major accomplishments with detailed descriptions of our experimental and theoretical efforts. Upon the successful conduction of this project, we have followed our proposed breakdown work structure completing most of the technical tasks. Finally, we have developed and demonstrated several optimized homogenously catalytic methane conversion systems involving applications of novel ionic liquids, which present much more superior performance than the Catalytica system (the best-to-date system) in terms of three times higher reaction rates and longer catalysts lifetime and much stronger resistance to water deactivation. We have developed in-depth mechanistic understandings on the complicated chemistry involved in homogenously catalytic methane oxidation as well as developed the unique yet effective experimental protocols (reactors, analytical tools and screening methodologies) for achieving a highly efficient yet economically feasible and environmentally friendly catalytic methane conversion system. The most important findings have been published, patented as well as reported to DOE in this Final Report and our 20 Quarterly Reports.
Valorization of Waste Lipids through Hydrothermal Catalytic Conversion to Liquid Hydrocarbon Fuels with in Situ Hydrogen Production

Energy Technology Data Exchange (ETDEWEB)

Kim, Dongwook; Vardon, Derek R.; Murali, Dheeptha; Sharma, Brajendra K.; Strathmann, Timothy J.

2016-03-07

We demonstrate hydrothermal (300 degrees C, 10 MPa) catalytic conversion of real waste lipids (e.g., waste vegetable oil, sewer trap grease) to liquid hydrocarbon fuels without net need for external chemical inputs (e.g., H2 gas, methanol). A supported bimetallic catalyst (Pt-Re/C; 5 wt % of each metal) previously shown to catalyze both aqueous phase reforming of glycerol (a triacylglyceride lipid hydrolysis coproduct) to H2 gas and conversion of oleic and stearic acid, model unsaturated and saturated fatty acids, to linear alkanes was applied to process real waste lipid feedstocks in water. For reactions conducted with an initially inert headspace gas (N2), waste vegetable oil (WVO) was fully converted into linear hydrocarbons (C15-C17) and other hydrolyzed byproducts within 4.5 h, and H2 gas production was observed. Addition of H2 to the initial reactor headspace accelerated conversion, but net H2 production was still observed, in agreement with results obtained for aqueous mixtures containing model fatty acids and glycerol. Conversion to liquid hydrocarbons with net H2 production was also observed for a range of other waste lipid feedstocks (animal fat residuals, sewer trap grease, dry distiller's grain oil, coffee oil residual). These findings demonstrate potential for valorization of waste lipids through conversion to hydrocarbons that are more compatible with current petroleum-based liquid fuels than the biodiesel and biogas products of conventional waste lipid processing technologies.
Hydrocarbon conversion with an attenuated superactive multimetallic catalytic composite

International Nuclear Information System (INIS)

Antos, G.J.

1981-01-01

Hydrocarbons are converted by contacting them at hydrocarbon conversion conditions with a novel attenuated superactive multimetallic catalytic composite comprising a combination of a catalytically effective amount of a pyrolyzed rhenium carbonyl component with a porous carrier material containing a uniform dispersion of catalytically effective amounts of a platinum group component, which is maintained in the elemental metallic state during the incorporation and pyrolysis of the rhenium carbonyl component, and of an iron component. In a highly preferred embodiment, this novel catalytic composite also contains a catalytically effective amount of a halogen component. The platinum group component, pyrolyzed rhenium carbonyl component, iron component and optional halogen component are preferably present in the multimetallic catalytic composite in amounts, calculated on an elemental basis, corresponding to about 0.01 to about 2 wt. % platinum group metal, about 0.01 to about 5 wt. % rhenium, about 0.005 to about 4 wt. % iron and about 0.1 to about 5 wt. % halogen. A key feature associated with the preparation of the subject catalytic composite is reaction of a rhenium carbonyl complex with a porous carrier material containing a uniform dispersion of an iron component and of a platinum group component maintained in the elemental state, whereby the interaction of the rhenium moiety with the platinum group moiety is maximized due to the platinophilic (i.e., platinum-seeking) propensities of the carbon monoxide ligands associated with the rhenium reagent. A specific example of the type of hydrocarbon conversion process disclosed herein is a process for the catalytic reforming of a low octane gasoline fraction wherein the gasoline fraction and a hydrogen stream are contacted with the attenuated superactive multimetallic catalytic composite at reforming conditions
Process for conversion of lignin to reformulated hydrocarbon gasoline

Science.gov (United States)

Shabtai, Joseph S.; Zmierczak, Wlodzimierz W.; Chornet, Esteban

1999-09-28

A process for converting lignin into high-quality reformulated hydrocarbon gasoline compositions in high yields is disclosed. The process is a two-stage, catalytic reaction process that produces a reformulated hydrocarbon gasoline product with a controlled amount of aromatics. In the first stage, a lignin material is subjected to a base-catalyzed depolymerization reaction in the presence of a supercritical alcohol as a reaction medium, to thereby produce a depolymerized lignin product. In the second stage, the depolymerized lignin product is subjected to a sequential two-step hydroprocessing reaction to produce a reformulated hydrocarbon gasoline product. In the first hydroprocessing step, the depolymerized lignin is contacted with a hydrodeoxygenation catalyst to produce a hydrodeoxygenated intermediate product. In the second hydroprocessing step, the hydrodeoxygenated intermediate product is contacted with a hydrocracking/ring hydrogenation catalyst to produce the reformulated hydrocarbon gasoline product which includes various desirable naphthenic and paraffinic compounds.
Effect of Ce2O3, La2O3 and ZnO additives on the oxygenates conversion into liquid hydrocarbons

Science.gov (United States)

Kachalov, V. V.; Lavrenov, V. A.; Lishchiner, I. I.; Malova, O. V.; Tarasov, A. L.; Zaichenko, V. M.

2018-01-01

A selective modifying effect of cerium, magnesium and zinc oxide additives on the activity and the selectivity of a pentasil group zeolite catalyst in the reaction of conversion of oxygenates (methanol and dimethyl ether) to liquid hydrocarbons was found. It was found that zinc oxide contributes to the stable operation of the zeolite catalyst in the conversion of oxygenates in the synthesis gas stream and leads to the production of gasolines with low durene content (not more than 6.1 wt%). The obtained results demonstrate the rationale for producing hydrocarbons from synthesis gas without the stage of oxygenate separation with their subsequent conversion to synthetic gasoline.
Biological Conversion of Sugars to Hydrocarbons Technology Pathway

Energy Technology Data Exchange (ETDEWEB)

Davis, R.; Biddy, M.; Tan, E.; Tao, L.; Jones, S.

2013-03-01

This technology pathway case investigates the biological conversion of biomass-derived sugars to hydrocarbon biofuels, utilizing data from recent literature references and information consistent with recent pilot-scale demonstrations at NREL. Technical barriers and key research needs have been identified that should be pursued for the pathway to become competitive with petroleum-derived gasoline-, diesel-, and jet-range hydrocarbon blendstocks.
Influence on moisture and hydrocarbons on conversion rate of tritium in catalytic reactors of fusion-DEMO detritiation system

International Nuclear Information System (INIS)

Edao, Yuki; Sato, Katsumi; Iwai, Yasunori; Hayashi, Takumi

2017-01-01

Thoughtful consideration of abnormal events such as fire is required to design and qualify a detritiation system (DS) of a nuclear fusion facility. Since conversion of tritium to tritiated vapor over catalyst is the key process of the DS, it is indispensable to evaluate the effect of excess moisture and hydrocarbons produced by combustion of cables on tritium conversion rate considering fire events. We conducted demonstration tests on tritium conversion under the following representative conditions: (I) leakage of tritium, (II) leakage of tritium plus moisture, and (III) leakage of tritium plus hydrocarbons. Detritiation behavior in the simulated room was assessed, and the amount of catalyst to fulfill the requirement on tritium conversion rate was evaluated. The dominant parameters for detritiation are the concentration of hydrogen in air and catalyst temperature. The tritium in the simulated room was decreased for condition (I) following ventilation theory. An initial reduction in conversion rate was measured for condition (II). To recover the reduction smoothly, it is suggested to optimize the power of preheater. An increase in catalyst temperature by heat of reaction of hydrocarbon combustion was evaluated for condition (III). The heat balance of catalytic reactor is a point to be carefully investigated to avoid runaway of catalyst temperature. (author)
Biological Conversion of Sugars to Hydrocarbons Technology Pathway

Energy Technology Data Exchange (ETDEWEB)

Davis, Ryan; Biddy, Mary J.; Tan, Eric; Tao, Ling; Jones, Susanne B.

2013-03-31

In support of the Bioenergy Technologies Office, the National Renewable Energy Laboratory (NREL) and the Pacific Northwest National Laboratory (PNNL) are undertaking studies of biomass conversion technologies to identify barriers and target research toward reducing conversion costs. Process designs and preliminary economic estimates for each of these pathway cases were developed using rigorous modeling tools (Aspen Plus and Chemcad). These analyses incorporated the best information available at the time of development, including data from recent pilot and bench-scale demonstrations, collaborative industrial and academic partners, and published literature and patents. This technology pathway case investigates the biological conversion of biomass derived sugars to hydrocarbon biofuels, utilizing data from recent literature references and information consistent with recent pilot scale demonstrations at NREL. Technical barriers and key research needs have been identified that should be pursued for the pathway to become competitive with petroleum-derived gasoline, diesel and jet range hydrocarbon blendstocks.
Method for the conversion of hydrocarbon charges

Energy Technology Data Exchange (ETDEWEB)

Whittam, T V

1976-11-11

The basis of the invention is the application of defined zeolites as catalysts to hydrocarbon conversion processes such as reformation, isomerization, dehydrocyclization, and cracking. By charging the zeolite carrier masses with 0.001 to 5% metal of the 8th group of the periodic system, preferably noble metals, a wide region of applications for the catalysts is achieved. A method for the isomerization of an alkyl benzene (or mixture of alkyl benzenes) in the liquid or gas phase under suitable temperature, pressure and flow-rate conditions, as well as in the presence of a cyclic hydrocarbon, is described as preferential model form of the invention; furthermore, a method for the reformation of a hydrocarbon fraction boiling in the gasoline or benzene boiling region and a method for the hydrocracking of hydrocarbon charge (e.g. naphtha, kerosine, gas oils) are given. Types of performance of the methods are explained using various examples.

Metal-Exchanged β Zeolites as Catalysts for the Conversion of Acetone to Hydrocarbons

Directory of Open Access Journals (Sweden)

Aurora J. Cruz-Cabeza

2012-01-01

Full Text Available Various metal-β zeolites have been synthesized under similar ion-exchange conditions. During the exchange process, the nature and acid strength of the used cations modified the composition and textural properties as well as the Brönsted and Lewis acidity of the final materials. Zeolites exchanged with divalent cations showed a clear decrease of their surface Brönsted acidity and an increase of their Lewis acidity. All materials were active as catalysts for the transformation of acetone into hydrocarbons. Although the protonic zeolite was the most active in the acetone conversion (96.8% conversion, the metal-exchanged zeolites showed varied selectivities towards different products of the reaction. In particular, we found the Cu-β to have a considerable selectivity towards the production of isobutene from acetone (over 31% yield compared to 7.5% of the protonic zeolite. We propose different reactions mechanisms in order to explain the final product distributions.
Reaction-transport simulations of non-oxidative methane conversion with continuous hydrogen removal: Homogeneous-heterogeneous methane reaction pathways

International Nuclear Information System (INIS)

Li, Lin; Borry, Richard W.; Iglesia, Enrique

2000-01-01

Detailed kinetic-transport models were used to explore thermodynamic and kinetic barriers in the non-oxidative conversion of CH4 via homogeneous and homogeneous-heterogeneous pathways and the effects of continuous hydrogen removal and of catalytic sites on attainable yields of useful C2-C10 products. The homogeneous kinetic model combines separately developed models for low-conversion pyrolysis and for chain growth to form large aromatics and carbon. The H2 formed in the reaction decreases CH4 pyrolysis rates and equilibrium conversions and it favors the formation of lighter products. The removal of H2 along tubular reactors with permeable walls increases reaction rates and equilibrium CH4 conversions. C2-C10 yields reach values greater than 90 percent at intermediate values of dimensionless transport rates (delta=1-10), defined as the ratio hydrogen transport and methane conversion rates. Homogeneous reactions require impractical residence times, even with H2 removal, because of slow initiation and chain transfer rates. The introduction of heterogeneous chain initiation pathways using surface sites that form methyl radicals eliminates the induction period without influencing the homogeneous product distribution. Methane conversion, however, occurs predominately in the chain transfer regime, within which individual transfer steps and the formation of C2 intermediates become limited by thermodynamic constraints. Catalytic sites alone cannot overcome these constraints. Catalytic membrane reactors with continuous H2 removal remove these thermodynamic obstacles and decrease the required residence time. Reaction rates become limited by homogeneous reactions of C2 products to form C6+ aromatics. Higher delta values lead to subsequent conversion of the desired C2-C10 products to larger polynuclear aromatics. We conclude that catalytic methane pyrolysis at the low temperatures required for restricted chain growth and the elimination of thermodynamics constraints via
Elucidation of the mechanism of conversion of methanol and ethanol to hydrocarbons on a new type of synthetic zeolite

NARCIS (Netherlands)

Derouane, E.G.; Nagy, J.B.; Dejaifve, P.; Hooff, van J.H.C.; Spekman, B.P.A.; Védrine, J.C.; Naccache, C.

1978-01-01

13C nuclear magnetic resonance and vapor-phase chromatography have been used to investigate the conversions of methanol and ethanol to hydrocarbons on a synthetic zeolite of the type H-ZSM-5 as described by Mobil. Methanol is first dehydrated to dimethyl ether and ethylene. Then the reaction
Fractional separation of hydrocarbon vapours

Energy Technology Data Exchange (ETDEWEB)

1937-07-10

A process is described for converting higher boiling hydrocarbons to lower boiling hydrocarbons by subjecting them at elevated temperatures to a conversion operation, then separating the higher and lower boiling fractions. The separation takes place while the reaction products are maintained in the vapor phase by contact with a mass of solid porous material which has little or no catalytic activity but does have a preferential absorption property for higher boiling hydrocarbons so that the lower boiling part of the reaction products pass through the separation zone while the heavier hydrocarbons are retained. The separation is accomplished without substantial loss of heat of these reaction products.
Process Design and Economics for the Conversion of Lignocellulosic Biomass to Hydrocarbons: Dilute-Acid and Enzymatic Deconstruction of Biomass to Sugars and Biological Conversion of Sugars to Hydrocarbons

Energy Technology Data Exchange (ETDEWEB)

Davis, R.; Tao, L.; Tan, E. C. D.; Biddy, M. J.; Beckham, G. T.; Scarlata, C.; Jacobson, J.; Cafferty, K.; Ross, J.; Lukas, J.; Knorr, D.; Schoen, P.

2013-10-01

This report describes one potential conversion process to hydrocarbon products by way of biological conversion of lingnocellulosic-dervied sugars. The process design converts biomass to a hydrocarbon intermediate, a free fatty acid, using dilute-acid pretreatement, enzymatic saccharification, and bioconversion. Ancillary areas--feed handling, hydrolysate conditioning, product recovery and upgrading (hydrotreating) to a final blendstock material, wastewater treatment, lignin combusion, and utilities--are also included in the design.
Syngas Conversion to Gasoline-Range Hydrocarbons over Pd/ZnO/Al2O3 and ZSM-5 Composite Catalyst System

Energy Technology Data Exchange (ETDEWEB)

Dagle, Robert A.; Lizarazo Adarme, Jair A.; Lebarbier, Vanessa MC; Gray, Michel J.; White, James F.; King, David L.; Palo, Daniel R.

2014-07-01

A composite Pd/ZnO/Al2O3-HZSM-5 (Si/Al=40) catalytic system was evaluated for the synthesis of gasoline-range hydrocarbons directly from synthesis gas. Bifunctional catalyst comprising PdZn metal and acid sites present the required catalytically active sites necessary for the methanol synthesis, methanol dehydration, and methanol-to-gasoline reactions. This system provides a unique catalytic pathway for the production of liquid hydrocarbons directly from syngas. However, selectivity control is difficult and poses many challenges. The composite catalytic system was evaluated under various process conditions. Investigated were the effects of temperature (310-375oC), pressure (300-1000 psig), time-on-stream (50 hrs), and gas-hour space velocity (740-2970 hr-1), using a H2/CO molar syngas ratio of 2.0. By operating at the lower end of the temperature range investigated, liquid hydrocarbon formation was favored, as was decreased amounts of undesirable light hydrocarbons. However, lower operating temperatures also facilitated undesirable CO2 formation via the water-gas shift reaction. Higher operating pressures slightly favored liquid synthesis. Operating at relatively low pressures (e.g. 300 psig) was made possible, whereas for methanol synthesis alone higher pressure are usually required to achieve similar conversion levels (e.g. 1000 psig). Thermodynamic constraints on methanol synthesis are eased by pushing the equilibrium through hydrocarbon formation. Catalytic performance was also evaluated by altering Pd and Zn composition of the Pd/ZnO/Al2O3 catalyst. Of the catalysts and conditions tested, selectivity toward liquid hydrocarbon was highest when using a 5% Pd metal loading and Pd/Zn molar ratio of 0.25 and mixed with HZMS-5, operating at 310oC and 300 psig, CO conversion was 43 % and selectivity (carbon weight basis) to hydrocarbons was 49 wt. %. Of the hydrocarbon fraction, 44wt. % was in the C5-C12 liquid product range and consisted primarily of aromatic
Conversion of oligomeric starch, cellulose, hydrolysates or sugars to hydrocarbons

Energy Technology Data Exchange (ETDEWEB)

Silks, Louis A; Sutton, Andrew; Kim, Jin Kyung; Gordon, John Cameron; Wu, Ruilian; Kimball, David B.

2017-09-05

Embodiments of the present invention are directed to the conversion of a source material (e.g., a depolymerized oligosaccharide mixture, a monomeric sugar, a hydrolysate, or a mixture of monomeric sugars) to intermediate molecules containing 7 to 26 contiguous carbon atoms. These intermediates may also be converted to saturated hydrocarbons. Such saturated hydrocarbons are useful as, for example, fuels.
Heterobimetallic Zeolite, InV-ZSM-5, Enables Efficient Conversion of Biomass Derived Ethanol to Renewable Hydrocarbons.

Science.gov (United States)

Narula, Chaitanya K; Li, Zhenglong; Casbeer, Erik M; Geiger, Robert A; Moses-Debusk, Melanie; Keller, Martin; Buchanan, Michelle V; Davison, Brian H

2015-11-03

Direct catalytic conversion of ethanol to hydrocarbon blend-stock can increase biofuels use in current vehicles beyond the ethanol blend-wall of 10-15%. Literature reports describe quantitative conversion of ethanol over zeolite catalysts but high C2 hydrocarbon formation renders this approach unsuitable for commercialization. Furthermore, the prior mechanistic studies suggested that ethanol conversion involves endothermic dehydration step. Here, we report the complete conversion of ethanol to hydrocarbons over InV-ZSM-5 without added hydrogen and which produces lower C2 (dehydration step is not necessary. Thus, our method of direct conversion of ethanol offers a pathway to produce suitable hydrocarbon blend-stock that may be blended at a refinery to produce fuels such as gasoline, diesel, JP-8, and jet fuel, or produce commodity chemicals such as BTX.
Cobalt catalysts for the conversion of methanol and for Fischer-tropsch synthesis to produce hydrocarbons

International Nuclear Information System (INIS)

Mauldin, C.H.; Davis, S.M.; Arcuri, K.B.

1987-01-01

A regeneration stable catalyst is described for the conversion at reaction conditions of methanol or synthesis gas to liquid hydrocarbons which consists essentially of from about 2 percent to about 25 percent cobalt, based on the weight of the catalyst composition, composited with titania, or a titania-containing support, to which is added sufficient of a zirconium, hafnium, cerium, or uranium promoter to provide a weight ratio of the zirconium, hafnium, cerium, or uranium metal:cobalt greater than about 0.101:1
Green technology for conversion of renewable hydrocarbon based on plasma-catalytic approach

Science.gov (United States)

Fedirchyk, Igor; Nedybaliuk, Oleg; Chernyak, Valeriy; Demchina, Valentina

2016-09-01

The ability to convert renewable biomass into fuels and chemicals is one of the most important steps on our path to green technology and sustainable development. However, the complex composition of biomass poses a major problem for established conversion technologies. The high temperature of thermochemical biomass conversion often leads to the appearance of undesirable byproducts and waste. The catalytic conversion has reduced yield and feedstock range. Plasma-catalytic reforming technology opens a new path for biomass conversion by replacing feedstock-specific catalysts with free radicals generated in the plasma. We studied the plasma-catalytic conversion of several renewable hydrocarbons using the air plasma created by rotating gliding discharge. We found that plasma-catalytic hydrocarbon conversion can be conducted at significantly lower temperatures (500 K) than during the thermochemical ( 1000 K) and catalytic (800 K) conversion. By using gas chromatography, we determined conversion products and found that conversion efficiency of plasma-catalytic conversion reaches over 85%. We used obtained data to determine the energy yield of hydrogen in case of plasma-catalytic reforming of ethanol and compared it with other plasma-based hydrogen-generating systems.
Conversion of hydrocarbons in solid oxide fuel cells

DEFF Research Database (Denmark)

Mogensen, Mogens Bjerg; Kammer Hansen, K.

2003-01-01

Recently, a number of papers about direct oxidation of methane and hydrocarbon in solid oxide fuel cells (SOFC) at relatively low temperatures (about 700degreesC) have been published. Even though the conversion of almost dry CH4 at 1000degreesC on ceramic anodes was demonstrated more than 10 years...
Chemistry of Furan Conversion into Aromatics and Olefins over HZSM-5: A Model Biomass Conversion Reaction

Energy Technology Data Exchange (ETDEWEB)

Cheng, Yu-Ting; Huber, George W.

2011-06-03

The conversion of furan (a model of cellulosic biomass) over HZSM-5 was investigated in a thermogravimetric analysis–mass spectrometry system, in situ Fourier transform infrared analysis, and in a continuous-flow fixed-bed reactor. Furan adsorbed as oligomers at room temperature with a 1.73 of adsorbed furan/Al ratio. These oligomers were polycyclic aromatic compounds that were converted to CO, CO₂, aromatics, and olefins at temperatures from 400 to 600 °C. Aromatics (e.g., benzene, toluene, and naphthalene), oligomer isomers (e.g., benzofuran, 2,2-methylenebisfuran, and benzodioxane), and heavy oxygenates (C₁₂{sub +} oligomers) were identified as intermediates formed inside HZSM-5 at different reaction temperatures. During furan conversion, graphite-type coke formed on the catalyst surface, which caused the aromatics and olefins formation to deactivate within the first 30 min of time on-stream. We have measured the effects of space velocity and temperature for furan conversion to help us understand the chemistry of biomass conversion inside zeolite catalysts. The major products for furan conversion included CO, CO₂, allene, C₂–C₆ olefins, benzene, toluene, styrene, benzofuran, indene, and naphthalene. The aromatics (benzene and toluene) and olefins (ethylene and propylene) selectivity decreased with increasing space velocity. Unsaturated hydrocarbons such as allene, cyclopentadiene, and aromatics selectivity increased with increasing space velocity. The product distribution was selective to olefins and CO at high temperatures (650 °C) but was selective to aromatics (benzene and toluene) at intermediate temperatures (450–600 °C). At low temperatures (450 °C), benzofuran and coke contributed 60% of the carbon selectivity. Several different reactions were occurring for furan conversion over zeolites. Some important reactions that we have identified in this study include Diels–Alder condensation (e.g., two furans form benzofuran and water
Catalytic conversion of carboxylic acids in bio-oil for liquid hydrocarbons production

International Nuclear Information System (INIS)

Wang, Shurong; Guo, Zuogang; Cai, Qinjie; Guo, Long

2012-01-01

Bio-oil must be upgraded to be suitable for use as a high-grade transport fuel. Crude bio-oil has a high content of carboxylic acids which can cause corrosion, and the high oxygen content of these acids also reduces the oil’s heating value. In this paper, acetic acid and propanoic acid were chosen as the model carboxylic acids in bio-oil. Their behavior in the production of liquid hydrocarbons during a catalytic conversion process was investigated in a micro-fixed bed reactor. The liquid organic phase from this catalytic conversion process mainly consisted of liquid hydrocarbons and phenol derivatives. Under the condition of low Liquid Hourly Space Velocity (LHSV), the liquid organic phase from acetic acid cracking had a selectivity of 22% for liquid hydrocarbons and a selectivity of 65% for phenol derivatives. The composition of the organic products changed considerably with the LHSV increasing to 3 h −1 . The selectivity for liquid hydrocarbons increased up to 52% while that for phenol derivatives decreased to 32%. Propanoic acid performed much better in producing liquid hydrocarbons than acetic acid. Its selectivity for liquid hydrocarbons was as high as 80% at LHSV = 3 h −1 . A mechanism for this catalytic conversion process was proposed according to the analysis of the components in the liquid organic phases. The pathways of the main compounds formation in the liquid organic phases were proposed, and the reason why liquid hydrocarbons were more effectively produced when using propanoic acid rather than acetic acid was also successfully explained. In addition, BET and SEM characterization were used to analyze the catalyst coke deposition. -- Graphical abstract: Display Omitted Highlights: ► High content of carboxylic acids in bio-oil causes its corrosiveness. ► Acetic acid and propanoic acid are two dominant acids in bio-oil. ► Liquid hydrocarbons were produced by cracking of these two dominant acids. ► A mechanism model was proposed to explain
Fractional Multistage Hydrothermal Liquefaction of Biomass and Catalytic Conversion into Hydrocarbons

Energy Technology Data Exchange (ETDEWEB)

Cortright, Randy [Virent, Inc., Madison, WI (United States); Rozmiarek, Robert [Virent, Inc., Madison, WI (United States); Dally, Brice [Virent, Inc., Madison, WI (United States); Holland, Chris [Virent, Inc., Madison, WI (United States)

2017-08-31

The objective of this project was to develop an improved multistage process for the hydrothermal liquefaction (HTL) of biomass to serve as a new front-end, deconstruction process ideally suited to feed Virent’s well-proven catalytic technology, which is already being scaled up. This process produced water soluble, partially de-oxygenated intermediates that are ideally suited for catalytic finishing to fungible distillate hydrocarbons. Through this project, Virent, with its partners, demonstrated the conversion of pine wood chips to drop-in hydrocarbon distillate fuels using a multi-stage fractional conversion system that is integrated with Virent’s BioForming® process. The majority of work was in the liquefaction task and included temperature scoping, solvent optimization, and separations.
Catalytic conversion of alcohols to hydrocarbons with low benzene content

Energy Technology Data Exchange (ETDEWEB)

Narula, Chaitanya K.; Davison, Brian H.; Keller, Martin

2016-03-08

A method for converting an alcohol to a hydrocarbon fraction having a lowered benzene content, the method comprising: converting said alcohol to a hydrocarbon fraction by contacting said alcohol, under conditions suitable for converting said alcohol to said hydrocarbon fraction, with a metal-loaded zeolite catalyst catalytically active for converting said alcohol to said hydrocarbon fraction, and contacting said hydrocarbon fraction with a benzene alkylation catalyst, under conditions suitable for alkylating benzene, to form alkylated benzene product in said hydrocarbon fraction. Also described is a catalyst composition useful in the method, comprising a mixture of (i) a metal-loaded zeolite catalyst catalytically active for converting said alcohol to said hydrocarbon, and (ii) a benzene alkylation catalyst, in which (i) and (ii) may be in a mixed or separated state. A reactor for housing the catalyst and conducting the reaction is also described.
Catalytic conversion of alcohols to hydrocarbons with low benzene content

Energy Technology Data Exchange (ETDEWEB)

Narula, Chaitanya K.; Davison, Brian H.; Keller, Martin

2016-09-06

A method for converting an alcohol to a hydrocarbon fraction having a lowered benzene content, the method comprising: converting said alcohol to a hydrocarbon fraction by contacting said alcohol, under conditions suitable for converting said alcohol to said hydrocarbon fraction, with a metal-loaded zeolite catalyst catalytically active for converting said alcohol to said hydrocarbon fraction, and contacting said hydrocarbon fraction with a benzene alkylation catalyst, under conditions suitable for alkylating benzene, to form alkylated benzene product in said hydrocarbon fraction. Also described is a catalyst composition useful in the method, comprising a mixture of (i) a metal-loaded zeolite catalyst catalytically active for converting said alcohol to said hydrocarbon, and (ii) a benzene alkylation catalyst, in which (i) and (ii) may be in a mixed or separated state. A reactor for housing the catalyst and conducting the reaction is also described.
Effect of NiO/SiO2 on thermo-chemical conversion of waste cooking oil to hydrocarbons

Directory of Open Access Journals (Sweden)

J. Sani

2017-05-01

Full Text Available Increase in organic waste generation, dwindling nature of global oil reserves coupled with environmental challenges caused by waste oil disposal and burning of fossil fuels necessitated the need for alternative energy resources. Waste cooking oil obtained from the frying fish outlet was analyzed for its physicochemical properties using ASTM D-975 methods. Acid and Iodine values of the oil were 30.43 ± 0.32 mgKOH/g and 57.08 ± 0.43 mgI2/100 g respectively. Thermo-chemical conversion of the oil using NiO/SiO2 at different reaction conditions (pressure, temperature, and catalyst concentration at a residence time of 3 h yielded 33.63% hydrocarbons. Hydro-catalytic pyrolysis of waste cooking oil at 400 °C, H2 pressure of 15 bars, and catalyst to oil ratio of 0.25 g/100 cm3 resulted in highest hydrocarbon yield (41.98%. The fuel properties of the product were: cetane number (71.16, high heating value (41.43 MJ/kg, kinematic viscosity (2.01 mm2/s, density (0.94 g/ml, saponification value (185.1 ± 3.96 mgKOH/g, and iodine value (20.57 ± 0.20 I2/100 g respectively. These results show that the NiO/SiO2 could be a suitable catalyst for conversion of waste vegetable oil to hydrocarbons. Keywords: Energy, Chemical engineering
Conversion of Dimethyl Ether to Branched Hydrocarbons Over Cu/BEA: the Roles of Lewis Acidic and Metallic Sites in H2 Incorporation

Energy Technology Data Exchange (ETDEWEB)

Hensley, Jesse E.; Schaidle, Joshua A.; Ruddy, Daniel A.; Cheah, Singfoong; Habas, Susan E.; Pan, Ming; Zhang, Guanghui; Miller, Jeffrey T.

2017-04-26

Conversion of biomass to fuels remains as one of the most promising approach to support our energy needs. It has been previously shown that the gasification of non-edible cellulosic biomass can be used to derive fuels like methanol and dimethyl ether (DME). However, the use of methanol and DME is limited due to the fact that they have low energy densities, poor lubricity and lower viscosity when compared to long-chain hydrocarbons. Increasing the blending percentage can also lead to undesired amounts of oxygenated molecules in the transportation fuel infrastructure, which restrict their applicability as jet or diesel fuels. Consequently, the petroleum-derived hydrocarbons remain as the main constituent of the middle-distillate based fuels. One way to increase the share of biofuels in middle-distillates is to use methanol/DME as building blocks for producing renewable, energy-dense hydrocarbons. One way to achieve this is by catalytically converting the DME and methanol to light olefins, followed by oligomerization to higher molecular weight premium alkanes, which can directly be used as kerosene/diesel fuels. Here, we report the catalytic dimerization of biomass-derived deoxygenated olefins into transportation fuel-range hydrocarbons under liquid-phase stirred-batch conditions. Specifically, the effect of operating conditions, such as reaction temperature, solvent-type, reaction duration and olefin-structure, on the conversion, selectivity and kinetics of dimerization of triptene (2,3,3-trimethyl-1-butene) were investigated. Triptene, as previously reported, is one of the major products of DME-homologation reaction over a BEA zeolite4. We show that triptene can be converted to high quality middle-distillates using a commercially available ion-exchange acid resin, Amberlyst-35 (dry) by the process of catalytic dimerization.
Process Design and Economics for the Conversion of Lignocellulosic Biomass to Hydrocarbons: Dilute-Acid and Enzymatic Deconstruction of Biomass to Sugars and Catalytic Conversion of Sugars to Hydrocarbons

Energy Technology Data Exchange (ETDEWEB)

Davis, R. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Tao, L. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Scarlata, C. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Tan, E. C. D. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Ross, J. [Harris Group Inc., New York, NY (United States); Lukas, J. [Harris Group Inc., New York, NY (United States); Sexton, D. [Harris Group Inc., New York, NY (United States)

2015-03-01

This report describes one potential conversion process to hydrocarbon products by way of catalytic conversion of lignocellulosic-derived hydrolysate. This model leverages expertise established over time in biomass deconstruction and process integration research at NREL, while adding in new technology areas for sugar purification and catalysis. The overarching process design converts biomass to die die diesel- and naphtha-range fuels using dilute-acid pretreatment, enzymatic saccharification, purifications, and catalytic conversion focused on deoxygenating and oligomerizing biomass hydrolysates.
Process of converting phenols into hydrocarbons

Energy Technology Data Exchange (ETDEWEB)

Seelig, S

1929-02-02

A process is disclosed for the conversion of phenols into hydrocarbons, characterized by preheating a mixture of phenols and hydrogen or hydrogen-producing gases to approximately the reaction temperature under pressure, heating by passage percussion-like through a bath of metal to the reaction temperature, and rapidly cooling.

Process Design and Economics for the Conversion of Lignocellulosic Biomass to Hydrocarbons via Indirect Liquefaction. Thermochemical Research Pathway to High-Octane Gasoline Blendstock Through Methanol/Dimethyl Ether Intermediates

Energy Technology Data Exchange (ETDEWEB)

Tan, E. C. D.; Talmadge, M.; Dutta, A.; Hensley, J.; Schaidle, J.; Biddy, M.; Humbird, D.; Snowden-Swan, L. J.; Ross, J.; Sexton, D.; Yap, R.; Lukas, J.

2015-03-01

This report was developed as part of the U.S. Department of Energy’s Bioenergy Technologies Office’s (BETO’s) efforts to enable the development of technologies for the production of infrastructure-compatible, cost-competitive liquid hydrocarbon fuels from lignocellulosic biomass feedstocks. The research funded by BETO is designed to advance the state of technology of biomass feedstock supply and logistics, conversion, and overall system sustainability. It is expected that these research improvements will be made within the 2022 timeframe. As part of their involvement in this research and development effort, the National Renewable Energy Laboratory and the Pacific Northwest National Laboratory investigate the economics of conversion pathways through the development of conceptual biorefinery process models and techno-economic analysis models. This report describes in detail one potential conversion process for the production of high-octane gasoline blendstock via indirect liquefaction of biomass. The processing steps of this pathway include the conversion of biomass to synthesis gas or syngas via indirect gasification, gas cleanup, catalytic conversion of syngas to methanol intermediate, methanol dehydration to dimethyl ether (DME), and catalytic conversion of DME to high-octane, gasoline-range hydrocarbon blendstock product. The conversion process configuration leverages technologies previously advanced by research funded by BETO and demonstrated in 2012 with the production of mixed alcohols from biomass. Biomass-derived syngas cleanup via reforming of tars and other hydrocarbons is one of the key technology advancements realized as part of this prior research and 2012 demonstrations. The process described in this report evaluates a new technology area for the downstream utilization of clean biomass-derived syngas for the production of high-octane hydrocarbon products through methanol and DME intermediates. In this process, methanol undergoes dehydration to
The coupling effect of gas-phase chemistry and surface reactions on oxygen permeation and fuel conversion in ITM reactors

KAUST Repository

Hong, Jongsup

2015-08-01

© 2015 Elsevier B.V. The effect of the coupling between heterogeneous catalytic reactions supported by an ion transport membrane (ITM) and gas-phase chemistry on fuel conversion and oxygen permeation in ITM reactors is examined. In ITM reactors, thermochemical reactions take place in the gas-phase and on the membrane surface, both of which interact with oxygen permeation. However, this coupling between gas-phase and surface chemistry has not been examined in detail. In this study, a parametric analysis using numerical simulations is conducted to investigate this coupling and its impact on fuel conversion and oxygen permeation rates. A thermochemical model that incorporates heterogeneous chemistry on the membrane surface and detailed chemical kinetics in the gas-phase is used. Results show that fuel conversion and oxygen permeation are strongly influenced by the simultaneous action of both chemistries. It is shown that the coupling somewhat suppresses the gas-phase kinetics and reduces fuel conversion, both attributed to extensive thermal energy transfer towards the membrane which conducts it to the air side and radiates to the reactor walls. The reaction pathway and products, in the form of syngas and C2 hydrocarbons, are also affected. In addition, the operating regimes of ITM reactors in which heterogeneous- or/and homogeneous-phase reactions predominantly contribute to fuel conversion and oxygen permeation are elucidated.
Methanol conversion to hydrocarbons using modified clinoptilolite catalysts. Investigation of catalyst lifetime and reactivation

Energy Technology Data Exchange (ETDEWEB)

Hutchings, G J; Themistocleous, T; Copperthwaite, R G

1988-10-17

A study of the deactivation and reactivation of modified clinoptilolite catalysts for methanol conversion to hydrocarbons is reported. Clinoptilolite catalysts, modified by either ammonium ion exchange or hydrochloric acid treatment, exhibit a short useful catalyst lifetime for this reaction (ca. 2-3 h) due to a high rate of coke deposition (3-5.10/sup -3/ g carbon/g catalyst/h). A comparative study of reactivation using oxygen, nitrous oxide and ozone/oxygen as oxidants indicated that nitrous oxide reactivation gives improved catalytic performance when compared to the activity and lifetime of the fresh catalyst. Both oxygen and ozone/oxygen were found to be ineffective for the reactivation of clinoptilolite. Initial studies of in situ on-line reactivation are also described. 3 figs., 15 refs., 4 tabs.
Cobalt catalysts, and use thereof for the conversion of methanol and for fischer-tropsch synthesis, to produce hydrocarbons

International Nuclear Information System (INIS)

Mauldin, C.H.; Davis, S.M.; Arcuri, K.B.

1988-01-01

This patent describes a process useful for the conversion of methanol to hydrocarbons which comprises contacting the methanol at reaction conditions with a catalyst which comprises from about 2 percent to about 25 percent cobalt, based on the weight of the catalyst composition, composited with titania, or a titania-containing support, to which is added a zirconium, hafnium, cerium, or uranium promoter, the weight ratio of the zirconium, hafnium, cerium, or uranium metal:cobalt being greater than about 0.010:1; the reaction conditions being defined within ranges as follows: Methanol:H/sub 2/ ratio: greater than about 4:1, Space Velocities, Hr/sup -1/:about 0.1 to 10, Temperatures, 0 C.:about 150 to 350, Methanol Partial Pressure, psia: about 100 to 1000
Motor fuels by hydrogenation of liquid hydrocarbons

Energy Technology Data Exchange (ETDEWEB)

1938-05-07

A process is disclosed for the production of knock-stable low-boiling motor fuels by conversion of liquid hydrocarbons which are vaporizable under the reaction conditions, which comprises passing the initial material at a temperature above 380/sup 0/C in a true vapor phase under pressure of more than 40 atmospheres together with hydrogen and gaseous hydrocarbons containing more than 1 carbon atom in the molecule in an amount by volume larger than that of the hydrogen over catalysts stable to poisoning stationarily confined in the reaction vessel.
Reaction kinetics and reaction heat on thermal decomposition of solvent containing unstable reactive hydrocarbons with nitric acid at Tomsk-7 reprocessing plant

International Nuclear Information System (INIS)

Nishio, Gunji; Watanabe, Kouji; Koike, Tadao; Miyato, Teijiro.

1996-12-01

For analyzing a cause of the Tomsk-7 accident at Russian reprocessing plant, it is necessary to determine reaction-rate constant and reaction heat for a thermal decomposition of TBP/kerosine containing unstable reactive hydrocarbons with nitric acid. In JAERI, the rate constant and reaction heat were obtained from data measured with a differential thermal analyzer (DTA) for unstable hydrocarbons such as n-butanol, n-butyl nitrate, aromatic hydrocarbons, and cyclic compounds. The safety evaluation of Tomsk tank ruptured by the reaction was carried out by heat balance calculations between heat generation and heat loss in the tank using these rate constants and reaction heats. Consequently, it is clear that the cause of the tank rupture would be due to an exothermic reaction of aromatic hydrocarbons in kerosine made by petroleum with the concentrated nitric acid of 14.2N. (author)
Process and catalysts for hydrocarbon conversion. [high antiknock motor fuel

Energy Technology Data Exchange (ETDEWEB)

1940-02-14

High anti-knock motor fuel is produced from hydrocarbons by subjecting it at an elevated temperature to contact with a calcined mixture of hydrated silica, hydrated alumina, and hydrated zirconia, substantially free from alkali metal compounds. The catalyst may be prepared by precipitating silica gel by the acidification of an aqueous solution of an alkali metal silicate, intimately mixing hydrated alumina and hydrated zirconia therewith, drying, purifying the composite to substantially remove alkali metal compounds, again drying, forming the dried material into particles, and finally calcining. The resultant conversion products may be fractionated to produce gasoline, hydrocarbon oil above gasoling boiling point range, and a gaseous fraction of olefins which are polymerized into gasoline boiling range polymers.
Modification of Catalysts for Steam Reforming of Fluid Hydrocarbons. Research of Gas-Dynamic Duct Cooling Using Planar and Framework Catalysts (CD-ROM)

National Research Council Canada - National Science Library

Kuranov, Alexander L

2005-01-01

.... One way of fuel conversion is the catalytic steam reforming of hydrocarbon. This reaction has a large heat capacity and gives maximum quantity of molecular hydrogen among known reactions of hydrocarbons...
Hydrocarbon conversion with cracking catalyst having co-combustion promoters lanthanum and iron

International Nuclear Information System (INIS)

Csicsery, S.M.

1979-01-01

A composition useful in hydrocarbon conversion processes such as catalytic cracking comprises 0.05 to 10 weight percent lanthanum associated with a refractory support. The composition may also include 0.02 to 10 weight percent iron. The refractory support is a zeolitic crystalline aluminosilicate
Autothermal reforming of liquid hydrocarbons for H{sub 2} production

Energy Technology Data Exchange (ETDEWEB)

Palm, C.; Montel, S.; Cremer, P.; Peters, R.; Stolten, D. [Forschungszentrum Juelich GmbH (Germany). Inst. for Materials and Processes in Energy Systems IWV-3: Process Engineering

2001-07-01

The process of autothermal reforming of hydrocarbons can be used for the production of hydrogen within a fuel cell system. The application of three precious metal catalysts for the autothermal reforming of alkane mixtures with boiling ranges between 235 and 325 C was examined. The experiments were carried out at n(O{sub 2})/n(C) = 0.40, n(H{sub 2}O)/n(C) = 2.20, a catalyst bed temperature between 730 and 570 C and a hydrocarbon feed of 30 g/h. The catalysts yielded different hydrocarbon conversions, which can be explained by differences in the activity for the steam reforming reaction. The most active catalyst was also successfully utilized in the conversion of 400 g/h hydrocarbon feed. (orig.)
Plasma Thermal Conversion of Methane to Acetylene

International Nuclear Information System (INIS)

Fincke, James Russell; Anderson, Raymond Paul; Hyde, Timothy Allen; Detering, Brent Alan; Wright, Randy Ben; Bewley, Randy Lee; Haggard, Delon C; Swank, William David

2002-01-01

This paper describes a re-examination of a known process for the direct plasma thermal conversion of methane to acetylene. Conversion efficiencies (% methane converted) approached 100% and acetylene yields in the 90-95% range with 2-4% solid carbon production were demonstrated. Specificity for acetylene was higher than in prior work. Improvements in conversion efficiency, yield, and specificity were due primarily to improved injector design and reactant mixing, and minimization of temperature gradients and cold boundary layers. At the 60-kilowatt scale cooling by wall heat transfer appears to be sufficient to quench the product stream and prevent further reaction of acetylene resulting in the formation of heavier hydrocarbon products or solid carbon. Significantly increasing the quenching rate by aerodynamic expansion of the products through a converging-diverging nozzle led to a reduction in the yield of ethylene but had little effect on the yield of other hydrocarbon products. While greater product selectivity for acetylene has been demonstrated, the specific energy consumption per unit mass of acetylene produced was not improved upon. A kinetic model that includes the reaction mechanisms resulting in the formation of acetylene and heavier hydrocarbons, through benzene, is described
evaluation of commercial FCC catalysts for hydrocarbon conversion. I. Physicochemical characterization and n-hexane conversion.

NARCIS (Netherlands)

Brait, A.; Brait, A.; Seshan, Kulathuiyer; Lercher, J.A.

1998-01-01

The physicochemical properties of six steam-stabilized, commercial FCC catalysts were compared in respect of their catalytic activity for n-hexane conversion. The conversion of n-hexane over these catalysts could be fully explained by three reaction pathways: protolytic cracking, protolytic
Microplasma reforming of hydrocarbons for fuel cell power

Science.gov (United States)

Besser, R. S.; Lindner, P. J.

The implementation of a microplasma approach for small scale reforming processes is explored as an alternative to more standard catalyst-based processes. Plasmas are a known approach to activating a chemical reaction in place of catalysts, and microplasmas are particularly attractive owing to their extremely high electron and power densities. Their inherent compactness gives them appeal for portable applications, but their modularity leads to scalability for higher capacity. We describe the realization of experimental microplasma reactors based on the microhollow cathode discharge (MHCD) structure by silicon micromachining for device fabrication. Experiments were carried out with model hydrocarbons methane and butane in the reactors within a microfluidic flow and analytical setup. We observe several key phenomena, including the ability to liberate hydrogen from the hydrocarbons at temperatures near ambient and sub-Watt input power levels, the tendency toward hydrocarbon decomposition rather than oxidation even in the presence of oxygen, and the need for a neutral carrier to obtain conversion. Mass and energy balances on these experiments revealed conversions up to nearly 50%, but the conversion of electrical power input to chemical reaction enthalpy was only on the order of 1%. These initial, exploratory results were recorded with devices and at process settings without optimization, and are hence promising for an emerging, catalyst-free reforming approach.
Theoretical Studies of Elementary Hydrocarbon Species and Their Reactions

Energy Technology Data Exchange (ETDEWEB)

Allen, Wesley D. [Univ. of Georgia, Athens, GA (United States). Dept. of Chemistry. Center for Computational Quantum Chemistry; Schaefer, III, Henry F. [Univ. of Georgia, Athens, GA (United States). Dept. of Chemistry. Center for Computational Quantum Chemistry

2015-11-14

This is the final report of the theoretical studies of elementary hydrocarbon species and their reactions. Part A has a bibliography of publications supported by DOE from 2010 to 2016 and Part B goes into recent research highlights.
Methane Conversion to C2 Hydrocarbons by Abnormal Glow Discharge at Atmospheric Pressure

International Nuclear Information System (INIS)

Dai Wei; Yu Hui; Chen Qi; Yin Yongxiang; Dai Xiaoyan

2005-01-01

Methane conversion to C 2 hydrocarbons has been investigated with the addition of hydrogen in a plasma reactor of abnormal glow discharge at atmospheric pressure. The aim of this experiment is to minimize coke formation and improve discharge stability. The typical conditions in the experiment are 300 ml of total feed flux and 400 W of discharge power. The experimental results show that methane conversion is from 91.6% to 35.2% in mol, acetylene selectivity is from 90.2% to 57.6%, and ethylene selectivity is approximately from 7.8% to 3.6%, where the coke increases gradually along with the increase of CH 4 /H 2 from 2: 8 to 9: 1. A stable discharge for a considerable running time can be obtained only at a lower ratio of CH 4 /H 2 2: 8 or 3: 7. These phenomena indicate that the coke deposition during methane conversion is obviously reduced by adding a large amount of hydrogen during an abnormal glow discharge. A qualitative interpretation is presented, namely, with abundant hydrogen, the possibility that hydrogen molecules are activated to hydrogen radicals is increased with the help of the abnormal glow discharge. These hydrogen radicals react with carbon radicals to form C 2 hydrocarbon products. Therefore, the deposition of coke is restrained
Subcritical hydrothermal conversion of organic wastes and biomass. Reaction pathways

Directory of Open Access Journals (Sweden)

Alejandro Amadeus Castro Vega

2007-01-01

Full Text Available Hydrothermal conversion is a procedure which emulates organic matter’s natural conversion into bio-crude having physical and chemical properties analogous to petroleum. The artificial transformation of biomass requi- res previous knowledge of the main reaction routes and product availability. The main component of biomass (depolymerisation by hydrolysis is presented in hydrothermal cellulose conversion, producing oligosaccharides which exhibit dehydration and retro-aldol condensation reactions for transforming into furfurals and carboxylic acids. Other biomass components (such as lignin, proteins, and fat esters present both hydrolysis and pyrolysis reaction routes. As long as biomass mainly contains carbohydrates, subcritical hydrothermal conversion products and their wastes will be fundamentally analogous to those displaying cellulose. These substances have added- value by far surpassing raw material’s acquisition cost. When the main hydrothermal conversion products’ O/C, H/C molar ratios as reported in literature are plotted, an evolutionary tralectory for conversion products appears to be closely or even overlapped with fossil fuels’ geological evolution.
Anaerobic Microbial Degradation of Hydrocarbons: From Enzymatic Reactions to the Environment.

Science.gov (United States)

Rabus, Ralf; Boll, Matthias; Heider, Johann; Meckenstock, Rainer U; Buckel, Wolfgang; Einsle, Oliver; Ermler, Ulrich; Golding, Bernard T; Gunsalus, Robert P; Kroneck, Peter M H; Krüger, Martin; Lueders, Tillmann; Martins, Berta M; Musat, Florin; Richnow, Hans H; Schink, Bernhard; Seifert, Jana; Szaleniec, Maciej; Treude, Tina; Ullmann, G Matthias; Vogt, Carsten; von Bergen, Martin; Wilkes, Heinz

2016-01-01

Hydrocarbons are abundant in anoxic environments and pose biochemical challenges to their anaerobic degradation by microorganisms. Within the framework of the Priority Program 1319, investigations funded by the Deutsche Forschungsgemeinschaft on the anaerobic microbial degradation of hydrocarbons ranged from isolation and enrichment of hitherto unknown hydrocarbon-degrading anaerobic microorganisms, discovery of novel reactions, detailed studies of enzyme mechanisms and structures to process-oriented in situ studies. Selected highlights from this program are collected in this synopsis, with more detailed information provided by theme-focused reviews of the special topic issue on 'Anaerobic biodegradation of hydrocarbons' [this issue, pp. 1-244]. The interdisciplinary character of the program, involving microbiologists, biochemists, organic chemists and environmental scientists, is best exemplified by the studies on alkyl-/arylalkylsuccinate synthases. Here, research topics ranged from in-depth mechanistic studies of archetypical toluene-activating benzylsuccinate synthase, substrate-specific phylogenetic clustering of alkyl-/arylalkylsuccinate synthases (toluene plus xylenes, p-cymene, p-cresol, 2-methylnaphthalene, n-alkanes), stereochemical and co-metabolic insights into n-alkane-activating (methylalkyl)succinate synthases to the discovery of bacterial groups previously unknown to possess alkyl-/arylalkylsuccinate synthases by means of functional gene markers and in situ field studies enabled by state-of-the-art stable isotope probing and fractionation approaches. Other topics are Mo-cofactor-dependent dehydrogenases performing O2-independent hydroxylation of hydrocarbons and alkyl side chains (ethylbenzene, p-cymene, cholesterol, n-hexadecane), degradation of p-alkylated benzoates and toluenes, glycyl radical-bearing 4-hydroxyphenylacetate decarboxylase, novel types of carboxylation reactions (for acetophenone, acetone, and potentially also benzene and
On the impact of olefins and aromatics in the methanol-to-hydrocarbon conversion over H-ZSM-5 catalysts

Energy Technology Data Exchange (ETDEWEB)

Sun, X.; Mueller, S.; Veen, A.C. van; Lercher, J.A. [Technische Univ. Muenchen, Garching (Germany). Dept. of Chemistry

2012-07-01

Methanol-to-hydrocarbons processes using HZSM-5 archetype acidic zeolites or zeotype SAPO-34 catalysts are regarded as a vital suite of conversion technologies to bypass petroleum-based routes for the production of specific fuels and petrochemical commodities. Special significance of the methanol chemistry originates from its versatility enabling selective transformations towards various products. Industry demonstrated successfully implementations of Methanol-To-Gasoline, Methanol-To-Olefin, and Methanol-To-Propylene processes, although the typical single-pass selectivity remained limited and recycling is necessary. Considerable fundamental research efforts both from experimental and computational sides contributed to unravel the underlying complex reaction mechanism. The indirect hydrocarbon pool mechanism, in which Broensted acid sites combined with adsorbed light olefins or lower methylbenzenes act as active centers, is generally accepted to explain the formation of light olefins. As olefin and aromatics populated catalytic sites show different reactivity in terms of activity and selectivity to ethylene or propylene, one could envision optimizing the product distribution by suitable co-feeding of specific hydrocarbons. The present work addresses three questions with an experimental study conducted under realistic MTP operation conditions: (1) How are ethylene and propylene formed at molecular level? (2) Which reaction pathway leads to the formation of undesired hydrogen transfer products? (3) Does olefin or aromatics co-feeding change the selectivity to ethylene or propylene? Xylenes and various olefins were co-fed with methanol to achieve a detailed understanding of the reaction mechanism over acidic HZSM-5 zeolites. Results suggest, that an olefin homologation/cracking route (olefin cycle) accounts for the autocatalytic (-like) nature and the majority of methanol consumption rather than the route involving aromatic intermediates (aromatics cycle). Co
Comparison of techniques for the determination of conversion during suspension polymerization reactions

Directory of Open Access Journals (Sweden)

J. C. Santos

2008-06-01

Full Text Available The determination of conversion during suspension polymerization reactions is not an easy task due to the heterogeneity of the reaction medium and the tendency of particles to agglomerate rapidly when stirring is stopped. Usually, bulk polymerization in ampoules is employed to study the kinetics of suspension polymerization reactions. In this work, a comparison of different techniques for the determination of conversion during suspension polymerization reactions is presented. Results showed a good agreement between the conversion obtained by gravimetry during styrene suspension polymerization and on-line conversion monitoring data using fiber-optic based Raman Spectroscopy. Nevertheless, the polymerization rate of styrene bulk polymerization carried out in ampoules was higher than the real reaction rate of styrene suspension polymerization due to slightly higher reaction temperatures. Simulation results using the experimental temperature data in a mathematical model confirmed these results.
Hydrocarbons conversions over mineral ion-exchangers used in uranium ore waste treatment

International Nuclear Information System (INIS)

Azzouz, A.

1988-05-01

Preliminary experiments were carried out in order to investigate catalytic activities in hydrocarbons reactions of natural and synthetic zeolites previously loaded with heavy elements as lanthanides and actinides in yellow cake treatment. This way could be considered as an interesting low coast alternative in revalorifying these mineral ion-exchangers. (author)

L'hydrodésazotation des distillats issus de la conversion des hydrocarbures lourds Hydrodenitrogenation of Distillates Issuing from the Conversion of Heavy Hydrocarbons

Directory of Open Access Journals (Sweden)

Toulhoat H.

2006-11-01

Full Text Available L'hydrodésazotation catalytique (HDN est un des points clés de la valorisation des hydrocarbures lourds par leur conversion en carburants. Les coupes lourdes sont riches en azote, et leur conversion produit des distillats eux-mêmes très riches en azote, qui ne pourront être absorbés par une raffinerie classique sans un sévère prétraitement désazotant. Ce problème se pose quel que soit le procédé de conversion mis en oeuvre. On propose donc une analyse de l'HDN comprenant la description des structures azotées rencontrées dans les coupes à traiter, la mise en évidence des réactions à promouvoir, et les règles de choix de catalyseurs et de conditions opératoires en découlant compte tenu des principales déterminantes thermodynamiques et cinétiques. Cette analyse s'appuie sur des résultats de recherche très récents. Elle conduit à la mise en évidence de solutions actuelles au problème posé, et ouvre des perspectives pour des améliorations futures. Catalytic hydrodenitrogenation (HDN is one of the key steps in the upgrading of heavy hydrocarbons by converting them into fuels. Heavy cuts are rich in nitrogen, and their conversion produces distillates that are also very rich in nitrogen, making them unable to be absorbed by a conventional refinery without a severe denitrogenation pretreatment. This problem occurs no matter what conversion process is implemented. Therefore, an analysis of HDN is proposed, including the description of the nitrogen structures encountered in the cuts to be treated, the description of the reactions to be promoted, and the resulting rules for choosing catalysts and operating conditions, in the light of the principal thermodynamic and kinetic constraints. This analysis is based on very recent research results. It leads to the recommending of solutions to the problem at hand and opens up prospects for future improvements.
Plasma conversion of methane into higher hydrocarbons at surfaces

Energy Technology Data Exchange (ETDEWEB)

Sackinger, W.M.; Kamath, V.A. [Univ. of Alaska, Fairbanks, AK (United States)

1995-12-31

Natural gas is widely abundant, is easily withdrawn from reservoirs, is commonly produced as an associated gas along with crude oil production, and is found in many geologic settings as a resource separate from oil. A much larger fraction of the natural gas may be produced from a gas reservoir, as compared with a crude oil reservoir. However, natural gas is normally transported by pipeline, and the energy throughput of such a pipeline is perhaps only 20% to 30% of the throughput of an oil pipeline of the same size and cost. Gas is difficult to transport in moderate quantities at low cost, as it must either have a special pipeline or must be liquified into LNG, shipped in cryogenic LNG tankers, and regasified chemical stability of methane has made it difficult to convert it directly into conventional hydrocarbon fuel mixtures, and has also impeded its use as a feedstock for petrochemical production. Experiments are described in which a methane plasma is created, and the resulting methyl and hydrogen ions have been accelerated within a microchannel array so that they interact with neutral methane molecules on the inside surfaces of the microchannels. No catalysts are used, and the device operates at room temperature. Impact energies of the ions are in the range of 15 ev to greater than 100 ev, and the energy delivered in the interaction at the surfaces has caused the production of larger hydrocarbon molecules, such as C{sub 2}H{sub 2}, C{sub 2}H{sub 4}, and C{sub 2}H{sub 6}, along with C{sub 3}, C{sub 4}, C{sub 5}, C{sub 6}, C{sub 7}, and C{sub 8} molecules. Conversion effectiveness is greater at higher pressure, due to the increased ionic activity. The costs of production of the plasma conversion devices are projected to be quite low, and the technology appears to be commercially and economically feasible.
Investigating the Influence of Mesoporosity in Zeolite Beta on its Catalytic Performance for the Conversion of Methanol to Hydrocarbons

KAUST Repository

Liu, Zhaohui

2015-08-26

Hierarchically porous zeolite Beta (Beta-MS) synthesized by a soft-templating method contains remarkable intra-crystalline mesoporosity, which reduces the diffusion length in zeolite channels down to several nanometers and alters the distribution of Al among distinct crystallographic sites. When used as a catalyst for the conversion of methanol to hydrocarbons (MTH) at 330 oC, Beta-MS exhibited a 2.7-fold larger conversion capacity, a 2.0-fold faster reaction rate, and a remarkably longer lifetime than conventional zeolite Beta (Beta-C). The superior catalytic performance of Beta-MS is attributed to its hierarchical structure, which offers full accessibility to all catalytic active sites. In contrast, Beta-C was easily deactivated because a layer of coke quickly deposited on the outer surfaces of the catalyst crystals, impeding access to interior active sites. This difference is clearly demonstrated by using electron microscopy combined with electron energy loss spectroscopy to probe the distribution of coke in the deactivated catalysts. At both low and high conversions, ranging from 20% to 100%, Beta-MS gave higher selectivity towards higher aliphatics (C4-C7) but lower ethene selectivity compared to Beta-C. Therefore, we conclude that a hierarchical structure decreases the residence time of methylbenzenes in zeolite micropores, disfavoring the propagation of the aromatic-based catalytic cycle. This conclusion is consistent with a recent report on ZSM-5 and is also strongly supported by our analysis of soluble coke species residing in the catalysts. Moreover, we identified an oxygen-containing compound, 4-methyl-benzaldehyde, in the coke, which has not been observed in the MTH reaction before.
Investigating the Influence of Mesoporosity in Zeolite Beta on its Catalytic Performance for the Conversion of Methanol to Hydrocarbons

KAUST Repository

Liu, Zhaohui; Dong, Xinglong; Zhu, Yihan; Emwas, Abdul-Hamid M.; Zhang, Daliang; Tian, Qiwei; Han, Yu

2015-01-01

Hierarchically porous zeolite Beta (Beta-MS) synthesized by a soft-templating method contains remarkable intra-crystalline mesoporosity, which reduces the diffusion length in zeolite channels down to several nanometers and alters the distribution of Al among distinct crystallographic sites. When used as a catalyst for the conversion of methanol to hydrocarbons (MTH) at 330 oC, Beta-MS exhibited a 2.7-fold larger conversion capacity, a 2.0-fold faster reaction rate, and a remarkably longer lifetime than conventional zeolite Beta (Beta-C). The superior catalytic performance of Beta-MS is attributed to its hierarchical structure, which offers full accessibility to all catalytic active sites. In contrast, Beta-C was easily deactivated because a layer of coke quickly deposited on the outer surfaces of the catalyst crystals, impeding access to interior active sites. This difference is clearly demonstrated by using electron microscopy combined with electron energy loss spectroscopy to probe the distribution of coke in the deactivated catalysts. At both low and high conversions, ranging from 20% to 100%, Beta-MS gave higher selectivity towards higher aliphatics (C4-C7) but lower ethene selectivity compared to Beta-C. Therefore, we conclude that a hierarchical structure decreases the residence time of methylbenzenes in zeolite micropores, disfavoring the propagation of the aromatic-based catalytic cycle. This conclusion is consistent with a recent report on ZSM-5 and is also strongly supported by our analysis of soluble coke species residing in the catalysts. Moreover, we identified an oxygen-containing compound, 4-methyl-benzaldehyde, in the coke, which has not been observed in the MTH reaction before.
Crystal-plane effects of MFI zeolite in catalytic conversion of methanol to hydrocarbons

KAUST Repository

Wang, Ning; Sun, Wenjing; Hou, Yilin; Ge, Binghui; Hu, Ling; Nie, Jingqi; Qian, Weizhong; Wei, Fei

2018-01-01

We report the direct characterization of coke information in the clearly resolved (0 1 0) and (1 0 0) planes of various anisotropic MFI zeolites using EELS techniques, in a model reaction of methanol to hydrocarbons. For the first time, we found
Coupling of separation and reaction in zeolite membrane reactor for hydroisomerization of hydrocarbons

Energy Technology Data Exchange (ETDEWEB)

Gora, L.; Jansen, J.C. [Ceramic Membrane Centre, The Pore, DelftChemTech, Delft Univ. of Technology, Delft (Netherlands)

2005-03-01

A zeolite membrane reactor has been developed for the hydroisomerization of hydrocarbons, in which the linear molecules are separated from branched ones on the silicalite-1 membrane prior to conversion of the permeated linear hydrocarbons to equilibrium levels on the catalyst bed. Model studies using C{sub 6} components are conducted. n-C{sub 6} separated from 2MP (selectivity 24) is converted for 72% with 36% selectivity towards di-branched isomers (at 393 K). The results indicate that platinum containing chlorinated alumina/silicalite-1 membrane reactor has a potential in upgrading octane values and offers advantages such as higher efficiency, better process control and lower consumption of energy. (orig.)
Coupling of separation and reaction in zeolite membrane reactor for hydroisomerization of hydrocarbons

Energy Technology Data Exchange (ETDEWEB)

Gora, L.; Maloncy, M.L.; Jansen, J.C. [Ceramic Membrane Centre, The Pore, DelftChemTech, Delft Univ. of Technology (Netherlands)

2004-07-01

A zeolite membrane reactor has been developed for the hydroisomerization of hydrocarbons, in which the linear molecules are separated from branch ones on the silicalite-1 membrane prior to conversion of the permeated linear hydrocarbons to equilibrium levels on the catalyst bed. A model studies using C6 components are conduct. Separated n-C6 from 2MP (selectivity 24) is converted for 72% with 36% selectivity towards di-branched isomers (at 393 K). The results indicate that platinum containing chlorinated alumina/silicalite-1 membrane reactor has a potential in upgrading octane values and offers advantages such as higher efficiency, better process control and lower consumption of energy. (orig.)
Low temperature coal depolymerization-liquefaction: conversion of a North Dakota lignite to a light hydrocarbon oil

Energy Technology Data Exchange (ETDEWEB)

Shabtai, J.; Yuan Zhang (University of Utah, Salt Lake City, UT (USA). Dept. of Fuels Engineering)

1989-10-01

A new low temperature method of coal liquefaction is described which includes intercalation of the coal with FeCl{sub 3}, depolymerization under supercritical conditions, and hydroprocessing of the depolymerized product. Results indicate a high yield conversion of lignites to light hydrocarbon oils. 6 refs., 4 figs., 1 tab.
A reaction mechanism for gasoline surrogate fuels for large polycyclic aromatic hydrocarbons

KAUST Repository

Raj, Abhijeet; Charry Prada, Iran David; Amer, Ahmad Amer; Chung, Suk-Ho

2012-01-01

This work aims to develop a reaction mechanism for gasoline surrogate fuels (n-heptane, iso-octane and toluene) with an emphasis on the formation of large polycyclic aromatic hydrocarbons (PAHs). Starting from an existing base mechanism for gasoline
An experimental and theoretical study of reaction steps relevant to the methanol-to-hydrocarbons reaction

Energy Technology Data Exchange (ETDEWEB)

Svelle, Stian

2004-07-01

The primary objective of the present work is to obtain new insight into the reaction mechanism of the zeolite catalyzed methanol-to-hydrocarbons (MTH) reaction. It was decided to use both experimental and computational techniques to reach this goal. An investigation of the n-butene + methanol system was therefore initiated. Over time, it became apparent that it was possible to determine the rate for the methylation of n-butene by methanol. The ethene and propene systems were therefore reexamined in order to collect kinetic information also for those cases. With the development of user-friendly quantum chemistry programs such as the Gaussian suite of programs, the possibility of applying quantum chemical methods to many types of problems has become readily available even for non-experts. When performing mechanistic studies, there is quite often a considerable synergy effect when combining experimental and computational approaches. The methylation reactions mentioned above turned out to be an issue well suited for quantum chemical investigations. The incentive for examining the halomethane reactivity was the clear analogy to the MTH reaction system. Alkene dimerization was also a reaction readily examined with quantum chemistry. As discussed in the introduction of this thesis, polymethylbenzenes, or their cationic counterparts, are suspected to be key intermediates in the MTH reaction. It was therefore decided to investigate the intrinsic reactivity of these species in the gas-phase by employing sophisticated mass spectrometric (MS) techniques in collaboration with the MS group at the Department of Chemistry, University of Oslo The data thus obtained will also be compared with results from an ongoing computational study on gas phase polymethylbenzenium reactivity. 6 papers presenting various studies are included. The titles are: 1) A Theoretical Investigation of the Methylation of Alkenes with Methanol over Acidic Zeolites. 2) A Theoretical Investigation of the
Reaction of active uranium and thorium with aromatic carbonyls and pinacols in hydrocarbon solvents

International Nuclear Information System (INIS)

Kahn, B.E.; Rieke, R.D.

1988-01-01

Highly reactive uranium and thorium metal powders have been prepared by reduction of the anhydrous metal(IV) chlorides in hydrocarbon solvents. The reduction employs the crystalline hydrocarbon-soluble reducing agent [(TMEDA)Li] 2 [Nap] (TMEDA = N,N,N',N'-tetramethylethylenediamine, Nap = naphthalene). The resulting active metal powders have been shown to be extremely reactive with oxygen-containing compounds and have been used in the reductive coupling of aromatic ketones giving tetra-arylethylenes. Reactions with pinacols have given some mechanistic insight into the ketone coupling reaction. These finely divided metal powders activate very weakly acidic C-H bonds forming metal hydrides, which can be transferred to organic substrates
Heterogeneous kinetic modeling of the catalytic conversion of cycloparaffins

Science.gov (United States)

Al-Sabawi, Mustafa N.

The limited availability of high value light hydrocarbon feedstocks along with the rise in crude prices has resulted in the international recognition of the vast potential of Canada's oil sands. With the recent expansion of Canadian bitumen production come, however, many technical challenges, one of which is the significant presence of aromatics and cycloparaffins in bitumen-derived feedstocks. In addition to their negative environmental impact, aromatics limit fluid catalytic cracking (FCC) feedstock conversion, decrease the yield and quality of valuable products such as gasoline and middle distillates, increase levels of polyaromatic hydrocarbons prone to form coke on the catalyst, and ultimately compromise the FCC unit performance. Although cycloparaffins do not have such negative impacts, they are precursors of aromatics as they frequently undergo hydrogen transfer reactions. However, cycloparaffin cracking chemistry involves other competing reactions that are complex and need much investigation. This dissertation provides insights and understanding of the fundamentals of the catalytic cracking of cycloparaffins using carefully selected model compounds such as methylcyclohexane (MCH) and decalin. Thermal and catalytic cracking of these cycloparaffins on FCC-type catalysts are carried out using the CREC Riser Simulator under operating conditions similar to those of the industrial FCC units in terms of temperature, reaction time, reactant partial pressure and catalyst-to-hydrocarbon ratio. The crystallite size of the supported zeolites is varied between 0.4 and 0.9 microns, with both activity and selectivity being monitored. Catalytic conversions ranged between 4 to 16 wt% for MCH and between 8 to 27 wt% for decalin. Reaction pathways of cycloparaffins are determined, and these include ring-opening, protolytic cracking, isomerization, hydrogen transfer and transalkylation. The yields and selectivities of over 60 and 140 products, formed during MCH and decalin
SiC Conversion Coating Prepared from Silica-Graphite Reaction

Directory of Open Access Journals (Sweden)

Back-Sub Sung

2017-01-01

Full Text Available The β-SiC conversion coatings were successfully synthesized by the SiO(v-graphite(s reaction between silica powder and graphite specimen. This paper is to describe the effects on the characteristics of the SiC conversion coatings, fabricated according to two different reaction conditions. FE-SEM, FE-TEM microstructural morphologies, XRD patterns, pore size distribution, and oxidation behavior of the SiC-coated graphite were investigated. In the XRD pattern and SAD pattern, the coating layers showed cubic SiC peak as well as hexagonal SiC peak. The SiC coatings showed somewhat different characteristics with the reaction conditions according to the position arrangement of the graphite samples. The SiC coating on graphite, prepared in reaction zone (2, shows higher intensity of beta-SiC main peak (111 in XRD pattern as well as rather lower porosity and smaller main pore size peak under 1 μm.
Utilization of biomass: Conversion of model compounds to hydrocarbons over zeolite H-ZSM-5

DEFF Research Database (Denmark)

Mentzel, Uffe Vie; Holm, Martin Spangsberg

2011-01-01

Zeolite catalyzed deoxygenation of small oxygenates present in bio-oil or selected as model compounds was performed under Methanol-to-Hydrocarbons (MTH) like reaction conditions using H-ZSM-5 as the catalyst. Co-feeding of the oxygenates with methanol generally decreases catalyst lifetime due...
Nature of hydrocarbon activation in oxidative ammonolysis of propane to acrylonitrile over a gallium-antimony oxide catalyst

Energy Technology Data Exchange (ETDEWEB)

Osipova, Z.G.; Sokolovskii, V.D.

1979-03-01

The nature of hydrocarbon activation in oxidative ammonolysis of propane to acrylonitrile over a gallium-antimony oxide catalyst GaSbNiPOx (1:3:1.5:1 atomic ratios of the elements) was studied by comparing the rate of this reaction at 550/sup 0/C and 5Vertical Bar3< by vol propane/6Vertical Bar3< ammonia/18.6Vertical Bar3< oxygen/70.4Vertical Bar3< helium reactant mixture with that of isobutane ammoxidation to methacrylonitrile under the same conditions, at low (Vertical Bar3; 20Vertical Bar3<) conversions that prevent secondary oxidation of the products. Both the over-all hydrocarbon conversion rate and that of nitrile formation were higher for propane, suggesting that the reactions proceed via the respective carbanions (probably primary carbanions), rather than carbocations or uncharged radicals.
Pulse radiolysis of alkanes in the gas-phase, ion-molecule reactions and neutralization mechanisms of hydrocarbon ions

International Nuclear Information System (INIS)

Ausloos, P.

1975-01-01

A discussion is presented of the fate of unreactive hydrocarbon ions in various selected gaseous systems. It is shown that experiments performed with the high radiation dose rates obtained in pulse radiolysis experiments have several advantages over conventional low dose rate experiments for the elucidation of the mechanism of homogeneous neutralization of unreactive hydrocarbon ions. This is so because the charged species has a much shorter lifetime with respect to neutralization under high dose rate (pulse radiolysis) conditions, so that the reaction of the ions with minor impurities or accumulated products is much less probable than in low dose rate experiments. It is further shown through a few examples, that quantitative information about the rate contants of neutralization events and ion-molecule reactions can be obtained when the dose rate is high enough for neutralization and chemical reaction to be in competition. Once reliable rate constants for neutralization and ion-molecule reactions are derived, one can obtain a quantitative evaluation of the products which will by formed in the pulse radiolysis of a hydrocarbon gas mixture from a computer calculation. (author)
Selective Synthesis of Gasoline-Ranged Hydrocarbons from Syngas over Hybrid Catalyst Consisting of Metal-Loaded ZSM-5 Coupled with Copper-Zinc Oxide

Directory of Open Access Journals (Sweden)

Ting Ma

2014-04-01

Full Text Available The conversion of syngas (CO + H2 to gasoline-ranged hydrocarbons was carried out using a hybrid catalyst consisting of metal-loaded ZSM-5 coupled with Cu-ZnO in a near-critical n-hexane solvent. Methanol was synthesized from syngas over Cu-ZnO; subsequently, was converted to hydrocarbons through the formation of dimethyl ether (DME over the metal-loaded ZSM-5. When 0.5 wt% Pd/ZSM-5 and 5 wt% Cu/ZSM-5 among the metal-loaded ZSM-5 catalysts with Pd, Co, Fe or Cu were employed as a portion of the hybrid catalyst, the gasoline-ranged hydrocarbons were selectively produced (the gasoline-ranged hydrocarbons in all hydrocarbons: 59% for the hybrid catalyst with Pd/ZSM-5 and 64% for that with Cu/ZSM-5 with a similar CO conversion during the reaction. An increase in the Cu loading on ZSM-5 resulted in increasing the yield of the gasoline-ranged hydrocarbons, and in decreasing the yield of DME. Furthermore, the hybrid catalyst with Cu/ZSM-5 exhibited no deactivation for 30 h of the reaction. It was revealed that a hybrid catalyst containing Cu/ZSM-5 was efficient in the selective synthesis of gasoline-ranged hydrocarbons from syngas via methanol in the near-critical n-hexane fluid.
An experimental and theoretical study of reaction steps relevant to the methanol-to-hydrocarbons reaction

Energy Technology Data Exchange (ETDEWEB)

Svelle, Stian

2004-07-01

The primary objective of the present work is to obtain new insight into the reaction mechanism of the zeolite catalyzed methanol-to-hydrocarbons (MTH) reaction. It was decided to use both experimental and computational techniques to reach this goal. An investigation of the n-butene + methanol system was therefore initiated. Over time, it became apparent that it was possible to determine the rate for the methylation of n-butene by methanol. The ethene and propene systems were therefore reexamined in order to collect kinetic information also for those cases. With the development of user-friendly quantum chemistry programs such as the Gaussian suite of programs, the possibility of applying quantum chemical methods to many types of problems has become readily available even for non-experts. When performing mechanistic studies, there is quite often a considerable synergy effect when combining experimental and computational approaches. The methylation reactions mentioned above turned out to be an issue well suited for quantum chemical investigations. The incentive for examining the halomethane reactivity was the clear analogy to the MTH reaction system. Alkene dimerization was also a reaction readily examined with quantum chemistry. As discussed in the introduction of this thesis, polymethylbenzenes, or their cationic counterparts, are suspected to be key intermediates in the MTH reaction. It was therefore decided to investigate the intrinsic reactivity of these species in the gas-phase by employing sophisticated mass spectrometric (MS) techniques in collaboration with the MS group at the Department of Chemistry, University of Oslo The data thus obtained will also be compared with results from an ongoing computational study on gas phase polymethylbenzenium reactivity. 6 papers presenting various studies are included. The titles are: 1) A Theoretical Investigation of the Methylation of Alkenes with Methanol over Acidic Zeolites. 2) A Theoretical Investigation of the
Spatial Distribution of Zeolite ZSM-5 within Catalyst Bodies Affects Selectivity and Stability of Methanol-to-Hydrocarbons Conversion

NARCIS (Netherlands)

Castaño, P.; Ruiz-Martinez, J.; Epelde, E.; Gayubo, A.G.; Weckhuysen, B.M.

2013-01-01

Solid acids, such as zeolites, are used as catalyst materials in a wide variety of important crude oil refinery, bulk chemical synthesis, and green processes. Examples include fluid catalytic cracking (FCC),[1] methanol-to-hydrocarbons (MTH) conversion,[ 2] plastic waste valorization,[3] and biomass
Inertial confinement fusion reaction chamber and power conversion system study

International Nuclear Information System (INIS)

Maya, I.; Schultz, K.R.; Battaglia, J.M.

1984-09-01

GA Technologies has developed a conceptual ICF reactor system based on the Cascade rotating-bed reaction chamber concept. Unique features of the system design include the use of low activation SiC in a reaction chamber constructed of box-shaped tiles held together in compression by prestressing tendons to the vacuum chamber. Circulating Li 2 O granules serve as the tritium breeding and energy transport material, cascading down the sides of the reaction chamber to the power conversion system. The total tritium inventory of the system is 6 kg; tritium recovery is accomplished directly from the granules via the vacuum system. A system for centrifugal throw transport of the hot Li 2 O granules from the reaction chamber to the power conversion system has been developed. A number of issues were evaluated during the course of this study. These include the response of first-layer granules to the intense microexplosion surface heat flux, cost effective fabrication of Li 2 O granules, tritium inventory and recovery issues, the thermodynamics of solids-flow options, vacuum versus helium-medium heat transfer, and the tradeoffs of capital cost versus efficiency for alternate heat exchange and power conversion system option. The resultant design options appear to be economically competitive, safe, and environmentally attractive

Effect of temperature on photochemical smog reactions

Energy Technology Data Exchange (ETDEWEB)

Bufalini, J J; Altshuller, A P

1963-01-01

In the present investigation the photo-oxidation reactions to trans-2-butene-nitric oxide and 1,3,5-trimethylbenzene (mesitylene)-nitric oxide in air have been followed. The rates of formation and disappearance of nitrogen dioxide and the rate of reaction of the hydrocarbons have been measured at 20 and 40/sup 0/. The results obtained indicate about a twofold decrease in conversion times over the 20/sup 0/ interval and a corresponding increase in rates of reactions. 5 references.
Conversion of associated natural gas to liquid hydrocarbons. Final report, June 1, 1995--January 31, 1997

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-12-31

The original concept envisioned for the use of Fischer-Tropsch processing (FTP) of United States associated natural gas in this study was to provide a way of utilizing gas which could not be brought to market because a pipeline was not available or for which there was no local use. Conversion of gas by FTP could provide a means of utilizing offshore associated gas which would not require installation of a pipeline or re-injection. The premium quality F-T hydrocarbons produced by conversion of the gas can be transported in the same way as the crude oil or in combination (blended) with it, eliminating the need for a separate gas transport system. FTP will produce a synthetic crude oil, thus increasing the effective size of the resource. The two conventional approaches currently used in US territory for handling of natural gas associated with crude petroleum production are re-injection and pipelining. Conversion of natural gas to a liquid product which can be transported to shore by tanker can be accomplished by FTP to produce hydrocarbons, or by conversion to chemical products such as methanol or ammonia, or by cryogenic liquefaction (LNG). This study considers FTP and briefly compares it to methanol and LNG. The Energy International Corporation cobalt catalyst, ratio adjusted, slurry bubble column F-T process was used as the basis for the study and the comparisons. An offshore F-T plant can best be accommodated by an FPSO (Floating Production, Storage, Offloading vessel) based on a converted surplus tanker, such as have been frequently used around the world recently. Other structure types used in deep water (platforms) are more expensive and cannot handle the required load.
Reactions between 52100 steel and tricresyl phosphate neat and mixed with hydrocarbon oil

International Nuclear Information System (INIS)

Arezzo, F.; Moore, R.L.

1987-01-01

Some of the results from a previous study which showed reactions between iron surfaces (52100 steel) and tricresyl phosphate (TCP) dissolved in hydrocarbon oil are discussed in this paper. This study had shown that microscale oxidation of the hydrocarbon oil and preferential adsorption phenomena within the oil system components may result in a desirable phosphate type of coating. This phosphate is organic and it is converted into iron phosphate on argon ion sputtering. Also discussed in this paper are the results of a more recent work which shows the reactivity of neat TCP with an identical 52100 steel surface. The results of electron spectroscopy for chemical analysis indicate that neat TCP behaves quite differently from TCP diluted in hydrocarbon oil. The phosphate generated on the metal surface by neat TCP yields predominantly a phosphide when subjected to argon ion sputtering. (orig.)
Selective conversion of butane into liquid hydrocarbon fuels on alkane metathesis catalysts

KAUST Repository

Szeto, Kaï Chung; Hardou, Lucie; Merle, Nicolas; Basset, Jean-Marie; Thivolle-Cazat, Jean; Papaioannou, Charalambos; Taoufik, Mostafa

2012-01-01

We report a selective direct conversion of n-butane into higher molecular weight alkanes (C 5+) by alkane metathesis reaction catalysed by silica-alumina supported tungsten or tantalum hydrides at moderate temperature and pressure. The product
Zeolitic catalytic conversion of alcohols to hydrocarbons

Science.gov (United States)

Narula, Chaitanya K.; Davison, Brian H.; Keller, Martin

2018-04-10

A method for converting an alcohol to a hydrocarbon, the method comprising contacting said alcohol with a metal-loaded zeolite catalyst at a temperature of at least 100.degree. C. and up to 550.degree. C., wherein said alcohol can be produced by a fermentation process, said metal is a positively-charged metal ion, and said metal-loaded zeolite catalyst is catalytically active for converting said alcohol to said hydrocarbon.
Zeolitic catalytic conversion of alochols to hydrocarbons

Energy Technology Data Exchange (ETDEWEB)

Narula, Chaitanya K.; Davison, Brian H.; Keller, Martin

2017-01-03

A method for converting an alcohol to a hydrocarbon, the method comprising contacting said alcohol with a metal-loaded zeolite catalyst at a temperature of at least 100.degree. C. and up to 550.degree. C., wherein said alcohol can be produced by a fermentation process, said metal is a positively-charged metal ion, and said metal-loaded zeolite catalyst is catalytically active for converting said alcohol to said hydrocarbon.
Formation of polycyclic aromatic hydrocarbons and soot in fuel-rich oxidation of methane in a laminar flow reactor

DEFF Research Database (Denmark)

Skjøth-Rasmussen, Martin Skov; Glarborg, Peter; Østberg, M.

2004-01-01

Conversion of methane to higher hydrocarbons, polycyclic aromatic hydrocarbons (PAHs), and soot was investigated under fuel-rich conditions in a laminar flow reactor. The effects of stoichiometry, dilution, and water vapor addition were studied at temperatures between 1073 and 1823 K. A chemical...... kinetic mechanism was established for methane oxidation, with emphasis on formation of higher hydrocarbons and PAH. A submodel for soot formation was adopted from the work of Frenklach and co-workers without changes. Modeling predictions showed good agreement with experimental results. Reactants, stable...... decrease with increasing addition of water vapor. The effect is described qualitatively by the reaction mechanism. The enhanced oxidation of acetylene is attributed to higher levels of hydroxyl radicals, formed from the reaction between the water vapor and hydrogen atoms....
Fundamentals of Hydrocarbon Upgrading to Liquid Fuels and Commodity Chemicals over Catalytic Metallic Nanoparticles

Science.gov (United States)

Chen, Tao

Promising new technologies for biomass conversion into fuels and chemical feedstocks rely on the production of bio-oils, which need to be upgraded in order to remove oxygen-containing hydrocarbons and water. A high oxygen concentration makes bio-oils acidic and corrosive, unstable during storage, and less energetically valuable per unit weight than petroleum-derived hydrocarbons. Although there are efficient processes for the production of bio-oils, there are no efficient technologies for their upgrading. Current technologies utilize traditional petroleum refining catalysts, which are not optimized for biomass processing. New upgrading technologies are, therefore, urgently needed for development of sustainable energy resources. Development of such new technologies, however, is severely hindered by a lack of fundamental understanding of how oxygen and oxygen-containing hydrocarbons derived from biomass interact with promising noble-metal catalysts. In this study, kinetic reaction measurements, catalyst characterization and quantum chemical calculations using density functional theory were combined for determining adsorption modes and reaction mechanisms of hydrocarbons in the presence of oxygen on surfaces of catalytic noble-metal nanoparticles. The results were used for developing improved catalyst formulations and optimization of reaction conditions. The addition of molybdenum to platinum catalysts was shown to improve catalytic activity, stability, and selectivity in hydrodeoxygenation of acetic acid, which served as a model biomass compound. The fundamental results that describe interactions of oxygen and hydrocarbons with noble-metal catalysts were extended to other reactions and fields of study: evaluation of the reaction mechanism for hydrogen peroxide decomposition, development of improved hydrogenation catalysts and determination of adsorption modes of a spectroscopic probe molecule.
Reaction mechanism of oxygen atoms with unsaturated hydrocarbons by the crossed molecular beams method

Energy Technology Data Exchange (ETDEWEB)

Buss, R.J.; Baseman, R.J.; Guozhong, H.; Lee, Y.T.

1982-04-01

From a series of studies of the reaction of oxygen atoms with unsaturated hydrocarbons using the crossed molecular beam method, the dominant reaction mechanisms were found to be the simple substitution reactions with oxygen atoms replacing H, Cl, Br atom or alkyl groups. Complication due to secondary reaction was avoided by carrying out experiments under single collisions and observing primary products directly. Primary products were identified by measuring the angular and velocity distributions of products at all the mass numbers which could be detected by the mass spectrometer, and from comparison of these distributions, applying the requirement of energy and momentum conservation.
Reaction Mechanism of Oxygen Atoms with Unsaturated Hydrocarbons by the Crossed-Molecular-Beams Method

Science.gov (United States)

Buss, R. J.; Baseman, R. J.; Guozhong, H.; Lee, Y. T.

1982-04-01

From a series of studies of the reaction of oxygen atoms with unsaturated hydrocarbons using the crossed molecular beam method, the dominant reaction mechanisms were found to be the simple substitution reactions with oxygen atoms replacing H, Cl, Br atom or alkyl groups. Complication due to secondary reaction was avoided by carrying out experiments under single collisions and observing primary products directly. Primary products were identified by measuring the angular and velocity distributions of products at all the mass numbers which could be detected by the mass spectrometer, and from comparison of these distributions, applying the requirement of energy and momentum conservation.
Effect of Cooling Methods on Methane Conversion via Dielectric-Barrier Discharges

International Nuclear Information System (INIS)

Wang Baowei; Yang Kuanhui; Xu Genhui

2008-01-01

Effects of cooling methods on stability and methane conversion rate using dielectric-barrier discharges (DBD) were systematically investigated in this article. The results showed that the methane conversion rate was as high as 44.43% in a pure methane system at a flow rate of 100 mL ± min -1 and an input power of 234.2 W with air cooling. A dark greenish and soft film-like carbon was deposited on the outer surface of quartz tube when the outer electrode was water-cooled, which decreased the methane conversion. With air cooling of inner electrode the selectivity of C 2 hydrocarbons was higher than that with other cooling methods, while the C 3 hydrocarbons had higher selectivity with flowing water cooling. Cooling the inner electrode could restrain the carbon deposition, but would decrease the methane conversion rate. The stability of both reaction and plasma operation can be improved through cooling the reactor. From thermodynamic analysis, it was found that the effective collisions frequency among the reactant molecules and free electrons (e - ) increased with temperature, which in turn led to a higher methane conversion rate and a change in the distribution of products.
Recent Advances in the Mechanistic Studies of Alkylaromatic Conversions over Zeolite Catalysts

International Nuclear Information System (INIS)

Min, Hyung-Ki; Hong, Suk Bong

2013-01-01

The transformation of alkylaromatic hydrocarbons using zeolite catalysts play big part in the current petrochemical industry. Here we review recent advances in the understanding of the reaction mechanisms of various alkylaromatic conversions with respect to the structural and physicochemical properties of zeolite catalysts employed. Indeed, the shape-selective nature of zeolite catalysts determines the type of reaction intermediates and hence the prevailing reaction mechanism together with the product distribution. The prospect of zeolite catalysis in the development of more efficient petrochemical processes is also described
Reversible aqueous zinc/manganese oxide energy storage from conversion reactions

Energy Technology Data Exchange (ETDEWEB)

Pan, Huilin; Shao, Yuyan; Yan, Pengfei; Cheng, Yingwen; Han, Kee Sung; Nie, Zimin; Wang, Chongmin; Yang, Jihui; Li, Xiaolin; Bhattacharya, Priyanka; Mueller, Karl T.; Liu, Jun

2016-04-18

Rechargeable aqueous batteries are attracting growing interest for energy storage due to their low cost and high safety. Fundamental understanding of highly reversible aqueous reactions is critical for building high-performance batteries. Herein, we studied the reversibility of Zn/MnO2 battery chemistry in mild aqueous MnSO4 electrolytes. α-MnO2 nanofibers were used as a high performance cathode. Our study provides good evidence for a conversion reaction mechanism through reversible formation of short nanorods and nanoparticle aggregates. This reversible conversion reaction provides an operating voltage of 1.44 V, high capacity of 285 mAh g-1, excellent rate and capacity retention of 92% after 5000 cycles. Zn metal anode also shows high reversibility in the mild aqueous MnSO4 electrolytes. The highly reversible and stable chemistries in aqueous Zn/MnO2 batteries open new opportunity for energy storage technologies with potentially high energy density, high safety, and low cost.
Steam cracking of hydrocarbons 6. Effect of dibenzyl sulfide and dibenzyl disulfide on reaction kinetics and coking

NARCIS (Netherlands)

Bajus, M.; Baxa, J.; Leclercq, P.A.; Rijks, J.A.

1983-01-01

The influence of aromatic sulfides on the kinetics and selectivity of hydrocarbon conversion by steam cracking and on pyrolytic coke formation was investigated in stainless steel tubular reactors with relatively large inner surface.The rate of decomposition of heptane (at 700 ‘C, 100 kPa, and a mass
Hydrogen addition reactions of aliphatic hydrocarbons in comets

Science.gov (United States)

Kobayashi, Hitomi; Watanabe, N.; Watanabe, Y.; Fukushima, T.; Kawakita, H.

2013-10-01

Comets are thought as remnants of early solar nebula. Their chemical compositions are precious clue to chemical and physical evolution of the proto-planetary disk. Some hydrocarbons such as C2H6, C2H2 and CH4 in comets have been observed by using near-infrared spectroscopy. Although the compositions of C2H6 were about 1% relative to the water in normal comets, there are few reports on the detection of C2H6 in ISM. Some formation mechanisms of C2H6 in ISM have been proposed, and there are two leading hypotheses; one is the dimerizations of CH3 and another is the hydrogen addition reactions of C2H2 on cold icy grains. To evaluate these formation mechanisms for cometary C2H6 quantitatively, it is important to search the C2H4 in comets, which is the intermediate product of the hydrogen addition reactions toward C2H6. However, it is very difficult to detect the C2H4 in comets in NIR (3 microns) regions because of observing circumstances. The hydrogen addition reactions of C2H2 at low temperature conditions are not well characterized both theoretically and experimentally. For example, there are no reports on the reaction rate coefficients of those reaction system. To determine the production rates of those hydrogen addition reactions, we performed the laboratory experiments of the hydrogenation of C2H2 and C2H4. We used four types of the initial composition of the ices: pure C2H4, pure C2H2, C2H2 on amorphous solid water (ASW) and C2H4 on ASW at three different temperatures of 10, 20, and 30K. We found 1) reactions are more efficient when there are ASW in the initial compositions of the ice; 2) hydrogenation of C2H4 occur more rapid than that of C2H2.
Thermal conversion of biomass to valuable fuels, chemical feedstocks and chemicals

Science.gov (United States)

Peters, William A [Lexington, MA; Howard, Jack B [Winchester, MA; Modestino, Anthony J [Hanson, MA; Vogel, Fredreric [Villigen PSI, CH; Steffin, Carsten R [Herne, DE

2009-02-24

A continuous process for the conversion of biomass to form a chemical feedstock is described. The biomass and an exogenous metal oxide, preferably calcium oxide, or metal oxide precursor are continuously fed into a reaction chamber that is operated at a temperature of at least 1400.degree. C. to form reaction products including metal carbide. The metal oxide or metal oxide precursor is capable of forming a hydrolizable metal carbide. The reaction products are quenched to a temperature of 800.degree. C. or less. The resulting metal carbide is separated from the reaction products or, alternatively, when quenched with water, hydolyzed to provide a recoverable hydrocarbon gas feedstock.
GAS-PHASE REACTIONS OF POLYCYCLIC AROMATIC HYDROCARBON ANIONS WITH MOLECULES OF INTERSTELLAR RELEVANCE

International Nuclear Information System (INIS)

Demarais, Nicholas J.; Yang Zhibo; Martinez, Oscar; Wehres, Nadine; Bierbaum, Veronica M.; Snow, Theodore P.

2012-01-01

We have studied reactions of small dehydrogenated polycyclic aromatic hydrocarbon anions with neutral species of interstellar relevance. Reaction rate constants are measured at 300 K for the reactions of phenide (C 6 H – 5 ), naphthalenide (C 10 H – 7 ), and anthracenide (C 14 H – 9 ) with atomic H, H 2 , and D 2 using a flowing afterglow-selected ion flow tube instrument. Reaction rate constants of phenide with neutral molecules (CO, O 2 , CO 2 , N 2 O, C 2 H 2 , CH 3 OH, CH 3 CN, (CH 3 ) 2 CO, CH 3 CHO, CH 3 Cl, and (CH 3 CH 2 ) 2 O) are also measured under the same conditions. Experimental measurements are accompanied by ab initio calculations to provide insight into reaction pathways and enthalpies. Our measured reaction rate constants should prove useful in the modeling of astrophysical environments, particularly when applied to dense regions of the interstellar and circumstellar medium.
Gas-phase Reactions of Polycyclic Aromatic Hydrocarbon Anions with Molecules of Interstellar Relevance

Science.gov (United States)

Demarais, Nicholas J.; Yang, Zhibo; Martinez, Oscar; Wehres, Nadine; Snow, Theodore P.; Bierbaum, Veronica M.

2012-02-01

We have studied reactions of small dehydrogenated polycyclic aromatic hydrocarbon anions with neutral species of interstellar relevance. Reaction rate constants are measured at 300 K for the reactions of phenide (C6H- 5), naphthalenide (C10H- 7), and anthracenide (C14H- 9) with atomic H, H2, and D2 using a flowing afterglow-selected ion flow tube instrument. Reaction rate constants of phenide with neutral molecules (CO, O2, CO2, N2O, C2H2, CH3OH, CH3CN, (CH3)2CO, CH3CHO, CH3Cl, and (CH3CH2)2O) are also measured under the same conditions. Experimental measurements are accompanied by ab initio calculations to provide insight into reaction pathways and enthalpies. Our measured reaction rate constants should prove useful in the modeling of astrophysical environments, particularly when applied to dense regions of the interstellar and circumstellar medium.
Tailoring gas-phase CO2 electroreduction selectivity to hydrocarbons at Cu nanoparticles

Science.gov (United States)

Merino-Garcia, I.; Albo, J.; Irabien, A.

2018-01-01

Copper-based surfaces appear as the most active catalysts for CO2 electroreduction to hydrocarbons, even though formation rates and efficiencies still need to be improved. The aim of the present work is to evaluate the continuous gas-phase CO2 electroreduction to hydrocarbons (i.e. ethylene and methane) at copper nanoparticulated-based surfaces, paying attention to particle size influence (ranging from 25-80 nm) on reaction productivity, selectivity, and Faraday efficiency (FE) for CO2 conversion. The effect of the current density and the presence of a microporous layer within the working electrode are then evaluated. Copper-based gas diffusion electrodes are prepared by airbrushing the catalytic ink onto carbon supports, which are then coupled to a cation exchange membrane (Nafion) in a membrane electrode assembly. The results show that the use of smaller copper nanoparticles (25 nm) leads to a higher ethylene production (1148 μmol m-2 s-1) with a remarkable high FE (92.8%), at the same time, diminishing the competitive hydrogen evolution reaction in terms of FE. This work demonstrates the importance of nanoparticle size on reaction selectivity, which may be of help to design enhanced electrocatalytic materials for CO2 valorization to hydrocarbons.
Selective conversion of butane into liquid hydrocarbon fuels on alkane metathesis catalysts

KAUST Repository

Szeto, Kaï Chung

2012-01-01

We report a selective direct conversion of n-butane into higher molecular weight alkanes (C 5+) by alkane metathesis reaction catalysed by silica-alumina supported tungsten or tantalum hydrides at moderate temperature and pressure. The product is unprecedented, asymmetrically distributed towards heavier alkanes. This journal is © 2012 The Royal Society of Chemistry.

Carbonyl atmospheric reaction products of aromatic hydrocarbons in ambient air

Science.gov (United States)

Obermeyer, Genevieve; Aschmann, Sara M.; Atkinson, Roger; Arey, Janet

To convert gaseous carbonyls to oximes during sampling, an XAD-4 resin denuder system pre-coated with O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine and followed by analysis with methane positive chemical ionization gas chromatography/mass spectrometry was used to measure carbonyls in ambient air samples in Riverside, CA. In conjunction with similar analyses of environmental chamber OH radical-initiated reactions of o- and p-xylene, 1,2,4-trimethylbenzene, ethylbenzene, 4-hydroxy-2-butanone and 1,4-butanediol, we identified benzaldehyde, o-, m- and p-tolualdehyde and acetophenone and the dicarbonyls glyoxal, methylglyoxal, biacetyl, ethylglyoxal, 1,4-butenedial, 3-hexene-2,5-dione, 3-oxo-butanal, 1,4-butanedial and malonaldehyde in the ambient air samples. As discussed, these carbonyls and dicarbonyls can be formed from the OH radical-initiated reactions of aromatic hydrocarbons and other volatile organic compounds emitted into the atmosphere, and we conclude that in situ atmospheric formation is a major source of these carbonyls in our Riverside, CA, ambient air samples.
Secondary reactions of tar during thermochemical biomass conversion[Dissertation 14341

Energy Technology Data Exchange (ETDEWEB)

Morf, P.O.

2001-07-01

This dissertation submitted to the Swiss Federal Institute of Technology in Zurich presents and discusses the results obtained during the examination of the processes involved in the formation and conversion of tar in biomass gasification plant. Details are given on the laboratory reactor system used to provide separated tar production and conversion for the purposes of the experiments carried out. The results of analyses made of the tar and the gaseous products obtained after its conversion at various temperatures are presented. The development of kinetic models using the results of the experiments that were carried out is described. The results of the experiments and modelling are compared with the corresponding results obtained using a full-scale down-draft, fixed-bed gasifier. The author is of the opinion that the reaction conditions found in full-scale gasifiers can be well simulated using heterogeneous tar conversion experiments using the lab reactor system.
Conversion of heavy aromatic hydrocarbons to valuable synthetic feed for steamcrackers

Energy Technology Data Exchange (ETDEWEB)

Cesana, A.; Dalloro, L.; Rivetti, F.; Buzzoni, R.; Bignazzi, R. [ENI S.p.A., Novara (Italy). Refining and Marketing Div.

2007-07-01

The scope of the present study was upgrading a set of heavy aromatic hydrocarbons mixtures whose commercial value ranks close to fuel oil and should become even lower in the next future because of the introduction of more stringent regulations on fuels, through hydro-conversion to a synthetic feed for steam-cracking. The resulting process provides an opportunity to improve the economic return of a steamcracking plant, offering the chance of converting low-value mixtures produced by the plant itself, such as fuel oil of cracking (FOK), saving an equivalent amount of naphtha. The method can also be used for converting pyrolysis gasoline (pygas). Although pygas has at present a fair commercial value, it could suffer a significant penalization in the future due to further limitations on total aromatic content in gasoline. Pygas hydro-conversion to a synthetic steam-cracking feedstock has been recently reported. Fractions from refinery, such as heavy distillates (e.g. Heavy Vacuum Gas Oil, VGO), deasphalted resides (DAO), or some FCC streams (e.g. LCO) resulted suitable and very attractive mixtures to be treated as well. No more than deasphalting was required as pretreatment of the feed mixture and only when the asphalts were >2%. Hetero-elements are often present in such kind of feeds at quite high concentrations, but no problems were observed due to the presence of sulphur and nitrogen, respectively, up to 15000 and 5500 ppm. (orig.)
Studies of Catalytic Properties of Inorganic Rock Matrices in Redox Reactions

Directory of Open Access Journals (Sweden)

Nikolay M. Dobrynkin

2017-09-01

Full Text Available Intrinsic catalytic properties of mineral matrices of various kinds (basalts, clays, sandstones were studied, which are of interest for in-situ heavy oil upgrading (i.e., underground to create advanced technologies for enhanced oil recovery. The elemental, surface and phase composition and matrix particle morphology, surface and acidic properties were studied using elemental analysis, X-ray diffraction, adsorption and desorption of nitrogen and ammonia. The data on the catalytic activity of inorganic matrices in ammonium nitrate decomposition (reaction with a large gassing, oxidation of hydrocarbons and carbon monoxide, and hydrocracking of asphaltenes into maltenes (the conversion of heavy hydrocarbons into more valuable light hydrocarbons were discussed. In order to check their applicability for the asphaltenes hydrocracking catalytic systems development, basalt and clay matrices were used as supports for iron/basalt, nickel/basalt and iron/clay catalysts. The catalytic activity of the matrices in the reactions of the decomposition of ammonium nitrate, oxidation of hydrocarbons and carbon monoxide, and hydrocracking of asphaltens was observed for the first time.
Technologies for hydrogen production based on direct contact of gaseous hydrocarbons and evaporated water with Molten Pb or Pb-Bi

International Nuclear Information System (INIS)

Gulevich, A. V.; Martynov, P. N.; Gulevsky, V. A.; Ulyanov, V. V.

2007-01-01

Results of studies intended for the substantiation of a new energy-saving and safe technology for low cost hydrogen production have been presented. The technology's basis is direct mixing of water and (or) gaseous hydrocarbons with heavy liquid metal coolants (HLMC) Pb or Pb-Bi. Preliminary research has been done on thermal dynamics and kinetics of the processes taking place in the interaction of HLMC with hydrocarbon-containing gases. It has been shown as a result that water and gaseous hydrocarbons interact with molten Pb and Pb-Bi relatively quietly in chemical aspect (without ignition and explosions). Therefore, (and taking into account the thermal physics, physical and chemical properties of HLMC such as low pressure of saturated vapor of Pb and Pb- Bi in enhanced temperatures, their good heat conductivity and heat capacity, low viscosity, etc.) heat transfer is possible from the molten metal to water and hydrocarbons without heat transferring partitions (that is, by direct contact of the working media). Devices to implement this method of heating liquid and gaseous media provide essential advantages: - A simple design; - None heat-transferring surfaces subject to corrosion, contamination, thermal fatigue, vibration impacts; - A high effectiveness owing to a larger heat exchanging surface per volume unit; - A small hydraulic resistance. The possibility and effectiveness of heating various gaseous and liquid media in their direct contact with molten Pb and Pb-Bi has been substantiated convincingly by experimental results at IPPE. Besides, the following processes of hydrogen-containing media conversion have been proved feasible thereby. 1. Water decomposition into hydrogen and oxygen. The process can develop at temperatures of 400-1000 degree C. It is necessary to provide constant removal of oxygen from the reaction zone and maintain a minimum possible content of chemically active oxygen in the melt. 2. Pyrolytic decomposition of hydrocarbons into carbon and
Catalytic Upgrading of Sugars to Hydrocarbons Technology Pathway

Energy Technology Data Exchange (ETDEWEB)

Biddy, M.; Jones, S.

2013-03-01

This technology pathway case investigates the catalytic conversion of solubilized carbohydrate streams to hydrocarbon biofuels, utilizing data from recent efforts within the National Advanced Biofuels Consortium (NABC) in collaboration with Virent, Inc. Technical barriers and key research needs that should be pursued for the catalytic conversion of sugars pathway to be competitive with petroleum-derived gasoline-, diesel-, and jet-range hydrocarbon blendstocks have been identified.
Cross sections and rate coefficients for charge exchange reactions of protons with hydrocarbon molecules

International Nuclear Information System (INIS)

Janev, R.K.; Kato, T.; Wang, J.G.

2001-05-01

The available experimental and theoretical cross section data on charge exchange processes in collisions of protons with hydrocarbon molecules have been collected and critically assessed. Using well established scaling relationships for the charge exchange cross sections at low and high collision energies, as well as the known rate coefficients for these reactions in the thermal energy region, a complete cross section database is constructed for proton-C x H y charge exchange reactions from thermal energies up to several hundreds keV for all C x H y molecules with x=1, 2, 3 and 1 ≤ y ≤ 2x + 2. Rate coefficients for these charge exchange reactions have also been calculated in the temperature range from 0.1 eV to 20 keV. (author)
Catalytic Upgrading of Sugars to Hydrocarbons Technology Pathway

Energy Technology Data Exchange (ETDEWEB)

Biddy, Mary J.; Jones, Susanne B.

2013-03-31

In support of the Bioenergy Technologies Office, the National Renewable Energy Laboratory (NREL) and the Pacific Northwest National Laboratory (PNNL) are undertaking studies of biomass conversion technologies to hydrocarbon fuels to identify barriers and target research toward reducing conversion costs. Process designs and preliminary economic estimates for each of these pathway cases were developed using rigorous modeling tools (Aspen Plus and Chemcad). These analyses incorporated the best information available at the time of development, including data from recent pilot and bench-scale demonstrations, collaborative industrial and academic partners, and published literature and patents. This technology pathway case investigates the catalytic conversion of solubilized carbohydrate streams to hydrocarbon biofuels, utilizing data from recent efforts within the National Advanced Biofuels Consortium (NABC) in collaboration with Virent, Inc.. Technical barriers and key research needs that should be pursued for the catalytic conversion of sugars pathway to be competitive with petroleum-derived gasoline, diesel and jet range hydrocarbon blendstocks have been identified.
Stability of Transition-metal Carbides in Liquid Phase Reactions Relevant for Biomass-Based Conversion

NARCIS (Netherlands)

Souza Macêdo, L.; Stellwagen, D.R.; Teixeira da Silva, V.; Bitter, J.H.

2015-01-01

Transition-metal carbides have been employed for biobased conversions aiming to replace the rare noble metals. However, when reactions are in liquid phase, many authors have observed catalyst deactivation. The main routes of deactivation in liquid phase biobased conversions are coke deposition,
Rate constants for the reaction of CF3O radicals with hydrocarbons at 298 K

DEFF Research Database (Denmark)

Kelly, C.; Treacy, J.; Sidebottom, H.W.

1993-01-01

Rate constant ratios of the reactions of CF3O radicals with a number of hydrocarbons have been determined at 298 +/- 2 K and atmospheric pressure using a relative rate method. Using a previously determined value k(CF30 + C2H6) = 1.2 x 10(-12) cm3 molecule-1 s-1 these rate constant ratios provide...... estimates of the rate constants: k(CF3O + CH4) = (1.2 +/- 0.1) x 10(-14), k(CF3O + c-C3H6) = (3.6 +/- 0.2) x 10(-13), k(CF3O + C3H8) = (4.7 +/- 0.7) x 10(-12), k(CF3O + (CH3)3CH) = (7.2 +/- 0.5) x 10(-12), k(CF3O + C2H4) = (3.0 +/- 0.1) x 10(-11) and k(CF3O + C6H6) = (3.6 +/- 0.1) x 10(-11) cm3 molecule-1 s......-1. The importance of the reactions of CF3O radicals with hydrocarbons under atmospheric conditions is discussed....
Special issue: Plasma Conversion

NARCIS (Netherlands)

Nozaki, T.; Bogaerts, A.; Tu, X.; van de Sanden, M. C. M.

2017-01-01

With growing concern of energy and environmental issues, the combination of plasma and heterogeneous catalysts receives special attention in greenhouse gas conversion, nitrogen fixation and hydrocarbon chemistry. Plasma gas conversion driven by renewable electricity is particularly important for the
Influence of vegetable oils fatty acid composition on reaction temperature and glycerides conversion to biodiesel during transesterification.

Science.gov (United States)

Pinzi, S; Gandía, L M; Arzamendi, G; Ruiz, J J; Dorado, M P

2011-01-01

Presence of unreacted glycerides in biodiesel may reduce drastically its quality. This is why conversion of raw material in biodiesel through transesterification needs to readjust reaction parameter values to complete. In the present work, monitoring of glycerides transformation in biodiesel during the transesterification of vegetable oils was carried out. To check the influence of the chemical composition on glycerides conversion, selected vegetable oils covered a wide range of fatty acid composition. Reactions were carried out under alkali-transesterification in the presence of methanol. In addition, a multiple regression model was proposed. Results showed that kinetics depends on chemical and physical properties of the oils. It was found that the optimal reaction temperature depends on both length and unsaturation degree of vegetable oils fatty acid chains. Vegetable oils with higher degree of unsaturation exhibit faster monoglycerides conversion to biodiesel. It can be concluded that fatty acid composition influences reaction parameters and glycerides conversion, hence biodiesel yield and economic viability. Copyright Â© 2010 Elsevier Ltd. All rights reserved.
Optrode for sensing hydrocarbons

Science.gov (United States)

Miller, H.; Milanovich, F.P.; Hirschfeld, T.B.; Miller, F.S.

1988-09-13

A two-phase system employing the Fujiwara reaction is provided for the fluorometric detection of halogenated hydrocarbons. A fiber optic is utilized to illuminate a column of pyridine trapped in a capillary tube coaxially attached at one end to the illuminating end of the fiber optic. A strongly alkaline condition necessary for the reaction is maintained by providing a reservoir of alkali in contact with the column of pyridine, the surface of contact being adjacent to the illuminating end of the fiber optic. A semipermeable membrane caps the other end of the capillary tube, the membrane being preferentially permeable to the halogenated hydrocarbon and but preferentially impermeable to water and pyridine. As the halogenated hydrocarbon diffuses through the membrane and into the column of pyridine, fluorescent reaction products are formed. Light propagated by the fiber optic from a light source, excites the fluorescent products. Light from the fluorescence emission is also collected by the same fiber optic and transmitted to a detector. The intensity of the fluorescence gives a measure of the concentration of the halogenated hydrocarbons. 5 figs.
Crystal-plane effects of MFI zeolite in catalytic conversion of methanol to hydrocarbons

KAUST Repository

Wang, Ning

2018-02-15

We report the direct characterization of coke information in the clearly resolved (0 1 0) and (1 0 0) planes of various anisotropic MFI zeolites using EELS techniques, in a model reaction of methanol to hydrocarbons. For the first time, we found that the main coke species varied between different planes and depended on the crystal structure. The coke species was graphite carbon and polyaromatic hydrocarbon over MFI nanosheets and MFI with b-axis length 60 nm, respectively. The diffusion of aromatics out of conventional MFI zeolites was found only through the straight channels, while small molecules randomly diffused through both channels, resulting in different coke deposition on the (0 1 0) plane and the (1 0 0) plane from different precursors. As all product molecules diffused only through the straight channels, the MFI nanosheet showed a distinct crystal-plane selective effect of coke deposition, in contrast to nearly uniform coke distribution throughout the entire external surface for conventional zeolites. This anisotropic diffusion behavior influenced the gaseous and liquid products significantly, providing deep insight into the MFI catalyst for the selective control of products via crystal structure.
Process and catalyst for the catalytic conversion of hydrocarbons

Energy Technology Data Exchange (ETDEWEB)

1939-10-27

A process is disclosed for converting hydrocarbon oils of higher than gasoline end boiling point, into large yields of motor fuel of high anti-knock value and substantial yields of normally gaseous readily polymerizable olefins, which comprises subjecting said hydrocarbon oils at a temperature within the approximate range of 425 to 650/sup 0/C. to contact with a catalytic material comprising hydrated silica and hydrated zirconia substantially free from alkali metal compounds.
Cross sections and rate coefficients for charge exchange reactions of protons with hydrocarbon molecules

Energy Technology Data Exchange (ETDEWEB)

Janev, R.K.; Kato, T. [National Inst. for Fusion Science, Toki, Gifu (Japan); Wang, J.G. [Department of Physics and Astronomy, University of Georgia, Athens (United States)

2001-05-01

The available experimental and theoretical cross section data on charge exchange processes in collisions of protons with hydrocarbon molecules have been collected and critically assessed. Using well established scaling relationships for the charge exchange cross sections at low and high collision energies, as well as the known rate coefficients for these reactions in the thermal energy region, a complete cross section database is constructed for proton-C{sub x}H{sub y} charge exchange reactions from thermal energies up to several hundreds keV for all C{sub x}H{sub y} molecules with x=1, 2, 3 and 1 {<=} y {<=} 2x + 2. Rate coefficients for these charge exchange reactions have also been calculated in the temperature range from 0.1 eV to 20 keV. (author)
Microbial conversion of higher hydrocarbons to methane in oil and coal reservoirs

Energy Technology Data Exchange (ETDEWEB)

Kruger, Martin; Beckmaann, Sabrina; Siegert, Michael; Grundger, Friederike; Richnow, Hans [Geomicrobiology Group, Federal Institute for Geosciences and Natural Resources (Germany)

2011-07-01

In recent years, oil production has increased enormously but almost half of the oil now remaining is heavy/biodegraded and cannot be put into production. There is therefore a need for new technology and for diversification of energy sources. This paper discusses the microbial conversion of higher hydrocarbons to methane in oil and coal reservoirs. The objective of the study is to identify microbial and geochemical controls on methanogenesis in reservoirs. A graph shows the utilization of methane for various purposes in Germany from 1998 to 2007. A degradation process to convert coal to methane is shown using a flow chart. The process for converting oil to methane is also given. Controlling factors include elements such as Fe, nitrogen and sulfur. Atmospheric temperature and reservoir pressure and temperature also play an important role. From the study it can be concluded that isotopes of methane provide exploration tools for reservoir selection and alkanes and aromatic compounds provide enrichment cultures.
Preparation of Peleted Ni-Pt/Zeolite for Conversion of Amyl and Isoamyl Alcohol to Hydrocarbon

Directory of Open Access Journals (Sweden)

Abdullah Abdullah

2010-06-01

Full Text Available Catalysts with Ni and Pt as active metals in peleted zeolite were used for conversion of amyl alcohol, isoamyl alcohol and their mixture to hydrocarbon compounds. The catalysts were prepared by impregnation the peleted zeolite in NiCl2.6H2O and PtCI4 solution, while stirring for 24 hours then followed by oxidation with 02 gas at 350 °C for 2 hours and reduced by hydrogen gas at 400 °C for 1 hour. Ni and Pt in catalysts were determined by MS, specific surface area, total pore volume and gas sorption analyzer NOVA-1000 determined pore radius average. Determination of catalysts acidity was carried out by absorption of ammonia method. The activity of catalysts was evaluated in a micro reactor by flow system. Experimental temperature by varied between 300 and 400 °C with the increment of 25 °C. Products were analyzed by gas chromatographic and mass spectrometric method. The result shows that Ni-Pt/zeolite is more active than Ni/zeolite can be used for converting all of the alcohol. Products for conversion are 2-pentene, 2-methyl-1-butene, 2-methyl-2-butene, cyclopentane, 3-methyl-1-butanaldehide and acetone. The highest conversion was observed on isoamyl alcohol (31.37% at 400 °C.
Hydrodeoxygenation of lignin-derived phenolic compounds to hydrocarbons over Ni/SiO2-ZrO2 catalysts.

Science.gov (United States)

Zhang, Xinghua; Zhang, Qi; Wang, Tiejun; Ma, Longlong; Yu, Yuxiao; Chen, Lungang

2013-04-01

Inexpensive non-sulfided Ni-based catalysts were evaluated for hydrodeoxygenation (HDO) using guaiacol as model compound. SiO2-ZrO2 (SZ), a complex oxide synthesized by precipitation method with different ratio of Si/Zr, was impregnated with Ni(NO3)2·6H2O and calcined at 500°C. Conversion rates and product distribution for guaiacol HDO at 200-340°C were determined. Guaiacol conversion reached the maximum at 300°C in the presence of Ni/SZ-3. When HDO reaction was carried out with real lignin-derived phenolic compounds under the optimal conditions determined for guaiacol, the total yield of hydrocarbons was 62.81%. These hydrocarbons were comprised of cyclohexane, alkyl-substituted cyclohexane and alkyl-substituted benzene. They have high octane number, would be the most desirable components for fungible liquid transportation fuel. Copyright © 2013 Elsevier Ltd. All rights reserved.
Zn-Mo/HZSM-5 Catalyst for Gasoil Range Hydrocarbon Production by Catalytic Hydrocracking of Ceiba pentandra oil

Directory of Open Access Journals (Sweden)

Yustia Wulandari Mirzayanti

2018-01-01

Full Text Available Biofuel from vegetable oil becomes one of the most suitable and logical alternatives to replace fossil fuel. The research focused on various metal ratio Zinc/Molybdenum/HZSM-5 (Zn-Mo/HZSM-5 catalyst to produce liquid hydrocarbon via catalytic hydrocracking of Ceiba penandra oil. The catalytic hydrocracking process has been applied in this study to crack Ceiba pentandra oil into a gasoil range hydrocarbon using Zn-Mo/HZSM-5 as a catalyst. The effect of various reaction temperature on the catalytic hydrocracking of Ceiba pentandra oil were studied. The Zn-Mo/HZSM-5 catalyst with metal ratio was prepared by incipient wetness impregnation method. This process used slurry pressure batch reactor with a mechanical stirrer. A series of experiments were carried out in the temperature range from 300-400 oC for 2 h at pressure between 10-15 bar. The conversion and selectivity were estimated. The liquid hydrocarbon product were identified to gasoline, kerosene, and gas oil. The results show that the use of Zn-Mo/HZSM-5 can produce gas oil as the most component in the product. Overall, the highest conversion and selectivity of gas oil range hydrocarbon was obtained when the ZnMo/HZSM-5 metal ratio was Zn(2.86 wt.%-Mo(5.32 wt.%/HZSM-5 and the name is Zn-Mo/HZSM-5_102. The highest conversion was obtained at 63.31 % and n-paraffin (gas oil range selectivity was obtained at 90.75 % at a temperature of 400 oC. Ceiba pentandra oil can be recommended as the source of inedible vegetable oil to produce gasoil as an environmentally friendly transportation fuel. Copyright © 2018 BCREC Group. All rights reserved Received: 8th September 2017; Revised: 9th September 2017; Accepted: 17th September 2017; Available online: 22nd January 2018; Published regularly: 2nd April 2018 How to Cite: Mirzayanti, Y.W., Kurniawansyah, F., Prajitno, D.H., Roesyadi, A. (2018. Zn-Mo/HZSM-5 Catalyst for Gasoil Range Hydrocarbon Production by Catalytic Hydrocracking of Ceiba pentandra

Hydrocarbons and air pollution

International Nuclear Information System (INIS)

Herz, O.

1992-01-01

This paper shows the influence of hydrocarbons vapors, emitted by transports or by volatile solvents using, on air pollution. Hydrocarbons are the principal precursors of photochemical pollution. After a brief introduction on atmospheric chemistry and photochemical reactions, the author describes the french prevention program against hydrocarbons emissions. In the last chapter, informations on international or european community programs for photochemical pollution study are given. 5 figs., 10 tabs
Rate constants and temperature effects for reactions of Cl2sm-bullet- with unsaturated alcohols and hydrocarbons in aqueous and acetonitrile/water solutions

International Nuclear Information System (INIS)

Padmaja, S.; Neta, P.; Huie, R.E.

1992-01-01

Absolute rate constants for reactions of the dichlorine radical anion, Cl 2 sm-bullet- , with unsaturated alcohols and hydrocarbons have been measured at various temperatures. The alcohol reactions were measured in aqueous solutions and the hydrocarbon reactions in 1:1 aqueous acetonitirle (ACN) solutions. The rate constants for two alcohols and one hydrocarbon were also examined as a function of solvent composition. The room temperature rate constants varied between 10 6 and 10 9 M -1 s -1 . The pre-exponential factors, A, were about (1-5) x 10 9 M -1 s -1 for the alcohols in aqueous solutions and about (0.1-1) x 10 9 M -1 s -1 for the hydrocarbons in aqueous ACN solutions. The activation energies, E a , varied considerably, between 4 and 12 kJ mol -1 for the alcohols and between 2 and 8 kJ mol -1 for the hydrocarbons. The rate constants, k 298 , decrease with increasing ionization potential (IP) of the unsaturated compound, in agreement with an electrophilic addition mechanism. The activation energies for the unsaturated alcohols decrease when the IP decreases from 9.7 to 9.1 eV but appear to level off at lower IP. Most alkenes studied had IP a . Upon addition of ACN to the aqueous solution, the values of log k 298 decreased linearly by more than 1 order of magnitude with increasing ACN mole fraction. This decrease appears to result from a combination of changes in the activation energy and in the pre-exponential factor. The reason for these changes may lie in changes in the solvation shell of the Cl 2 sm-bullet- radical, which will affect the A factor, in combination with changes in solvation of Cl - , which will affect the energetics of the reactions as well. 20 refs., 7 figs., 6 tabs
MULTICOMPONENT DETERMINATION OF CHLORINATED HYDROCARBONS USING A REACTION-BASED CHEMICAL SENSOR .2. CHEMICAL SPECIATION USING MULTIVARIATE CURVE RESOLUTION

NARCIS (Netherlands)

Tauler, R.; Smilde, A. K.; HENSHAW, J. M.; BURGESS, L. W.; KOWALSKI, B. R.

1994-01-01

A new multivariate curve resolution method that can extract analytical information from UV/visible spectroscopic data collected from a reaction-based chemical sensor is proposed. The method is demonstrated with the determination of mixtures of chlorinated hydrocarbons by estimating the kinetic and
[Alanine solution as enzyme reaction buffer used in A to O blood group conversion].

Science.gov (United States)

Li, Su-Bo; Zhang, Xue; Zhang, Yin-Ze; Tan, Ying-Xia; Bao, Guo-Qiang; Wang, Ying-Li; Ji, Shou-Ping; Gong, Feng; Gao, Hong-Wei

2014-06-01

The aim of this study was to investigate the effect of alanine solution as α-N-acetylgalactosaminidase enzyme reaction buffer on the enzymatic activity of A antigen. The binding ability of α-N-acetylgalactosaminidase with RBC in different reaction buffer such as alanine solution, glycine solution, normal saline (0.9% NaCl), PBS, PCS was detected by Western blot. The results showed that the efficiency of A to O conversion in alanine solution was similar to that in glycine solution, and Western blot confirmed that most of enzymes blinded with RBC in glycine or alanine solution, but few enzymes blinded with RBC in PBS, PCS or normal saline. The evidences indicated that binding of enzyme with RBC was a key element for A to O blood group conversion, while the binding ability of α-N-acetylgalactosaminidase with RBC in alanine or glycine solution was similar. It is concluded that alanine solution can be used as enzyme reaction buffer in A to O blood group conversion. In this buffer, the α-N-acetylgalactosaminidase is closely blinded with RBC and α-N-acetylgalactosaminidase plays efficient enzymatic activity of A antigen.
Modification of the performance of WO3-ZrO2 catalysts by metal addition in hydrocarbon reactions

Directory of Open Access Journals (Sweden)

Gerardo Carlos Torres

2012-01-01

Full Text Available A study of the different hydrocarbon reactions over Ni doped WO3-ZrO2 catalysts was performed. Ni was found as NiO at low Ni concentration while at high Ni concentrations a small fraction was present as a metal. For both cases, Ni strongly modified total acidity and concentration of strong acid sites. In the cyclohexane dehydrogenation reaction, Ni addition promotes both benzene and methyl cyclopentane production. The hydroconversion activity (n-butane and n-octane increases with the augment of total acidity produced by Ni. The selectivity to reaction products is modified according to the acid strength distribution changes produced by Ni addition.
The photochemical reaction of hydrocarbons under extreme thermobaric conditions

Science.gov (United States)

Serovaiskii, Aleksandr; Kolesnikov, Anton; Mukhina, Elena; Kutcherov, Vladimir

2017-10-01

The photochemical reaction of hydrocarbons was found to play an important role in the experiments with the synthetic petroleum conducted in Diamond Anvil Cell (DAC). Raman spectroscopy with a green laser (514.5 nm) was used for in situ sample analysis. This photochemical effect was investigated in the pressure range of 0.7-5 GPa, in the temperature interval from the ambient conditions to 450°C. The power of laser used in these experiment series was from 0.05 W to 0.6 W. The chemical transformation was observed when the necessary threshold pressure (~2.8 GPa) was reached. This transformation correlated with the luminescence appearance on the Raman spectra and a black opaque spot in the sample was observed in the place where the laser focus was forwarded. The exposure time and laser power (at least in the 0.1-0.5 W range) did not play a role in the 0.1-0.5 GPa range.
Study of parameters affecting the conversion in a plug flow reactor for reactions of the type 2A→B

Science.gov (United States)

Beltran-Prieto, Juan Carlos; Long, Nguyen Huynh Bach Son

2018-04-01

Modeling of chemical reactors is an important tool to quantify reagent conversion, product yield and selectivity towards a specific compound and to describe the behavior of the system. Proposal of differential equations describing the mass and energy balance are among the most important steps required during the modeling process as they play a special role in the design and operation of the reactor. Parameters governing transfer of heat and mass have a strong relevance in the rate of the reaction. Understanding this information is important for the selection of reactor and operating regime. In this paper we studied the irreversible gas-phase reaction 2A→B. We model the conversion that can be achieved as function of the reactor volume and feeding temperature. Additionally, we discuss the effect of activation energy and the heat of reaction on the conversion achieved in the tubular reactor. Furthermore, we considered that dimerization occurs instantaneously in the catalytic surface to develop equations for the determination of rate of reaction per unit area of three different catalytic surface shapes. This data can be combined with information about the global rate of conversion in the reactor to improve regent conversion and yield of product.
Steam hydrocarbon cracking and reforming

NARCIS (Netherlands)

Golombok, M.

2004-01-01

Many industrial chemical processes are taught as distinct contrasting reactions when in fact the unifying comparisons are greater than the contrasts. We examine steam hydrocarbon reforming and steam hydrocarbon cracking as an example of two processes that operate under different chemical reactivity
Systems and processes for conversion of ethylene feedstocks to hydrocarbon fuels

Science.gov (United States)

Lilga, Michael A.; Hallen, Richard T.; Albrecht, Karl O.; Cooper, Alan R.; Frye, John G.; Ramasamy, Karthikeyan Kallupalayam

2018-04-03

Systems, processes, and catalysts are disclosed for obtaining fuel and fuel blends containing selected ratios of open-chain and closed-chain fuel-range hydrocarbons suitable for production of alternate fuels including gasolines, jet fuels, and diesel fuels. Fuel-range hydrocarbons may be derived from ethylene-containing feedstocks and ethanol-containing feedstocks.
Systems and processes for conversion of ethylene feedstocks to hydrocarbon fuels

Science.gov (United States)

Lilga, Michael A.; Hallen, Richard T.; Albrecht, Karl O.; Cooper, Alan R.; Frye, John G.; Ramasamy, Karthikeyan Kallupalayam

2017-09-26

Systems, processes, and catalysts are disclosed for obtaining fuels and fuel blends containing selected ratios of open-chain and closed-chain fuel-range hydrocarbons suitable for production of alternate fuels including gasolines, jet fuels, and diesel fuels. Fuel-range hydrocarbons may be derived from ethylene-containing feedstocks and ethanol-containing feedstocks.
Production of light hydrocarbons, etc. [from heavy hydrocarbons

Energy Technology Data Exchange (ETDEWEB)

1937-10-07

A process is given for the production of light hydrocarbons of the gasoline type and, if desired, of the middle-oil type, from liquid or fusible heavy or medium heavy hydrocarbon materials. The process comprises subjecting the said initial materials in the first stage to catalytic hydrofining, separating the lower boiling constituents and the hydrogenating gas from the resulting products and then subjecting the higher boiling constituents in a second stage to a splitting destructive hydrogenation and then recycling substantially the entire reaction mixture obtained in the second stage to the frst stage.
Catalytic conversion of light alkanes

Energy Technology Data Exchange (ETDEWEB)

Lyons, J.E.

1992-06-30

The second Quarterly Report of 1992 on the Catalytic Conversion of Light Alkanes reviews the work done between April 1, 1992 and June 31, 1992 on the Cooperative Agreement. The mission of this work is to devise a new catalyst which can be used in a simple economic process to convert the light alkanes in natural gas to oxygenate products that can either be used as clean-burning, high octane liquid fuels, as fuel components or as precursors to liquid hydrocarbon uwspomdon fuel. During the past quarter we have continued to design, prepare, characterize and test novel catalysts for the mild selective reaction of light hydrocarbons with air or oxygen to produce alcohols directly. These catalysts are designed to form active metal oxo (MO) species and to be uniquely active for the homolytic cleavage of the carbon-hydrogen bonds in light alkanes producing intermediates which can form alcohols. We continue to investigate three molecular environments for the active catalytic species that we are trying to generate: electron-deficient macrocycles (PHASE I), polyoxometallates (PHASE II), and regular oxidic lattices including zeolites and related structures as well as other molecular surface structures having metal oxo groups (PHASE I).
Pyrochlore-type catalysts for the reforming of hydrocarbon fuels

Science.gov (United States)

Berry, David A [Morgantown, WV; Shekhawat, Dushyant [Morgantown, WV; Haynes, Daniel [Morgantown, WV; Smith, Mark [Morgantown, WV; Spivey, James J [Baton Rouge, LA

2012-03-13

A method of catalytically reforming a reactant gas mixture using a pyrochlore catalyst material comprised of one or more pyrochlores having the composition A.sub.2-w-xA'.sub.wA''.sub.xB.sub.2-y-zB'.sub.yB''.sub.zO.sub.7-.DELTA.. Distribution of catalytically active metals throughout the structure at the B site creates an active and well dispersed metal locked into place in the crystal structure. This greatly reduces the metal sintering that typically occurs on supported catalysts used in reforming reactions, and reduces deactivation by sulfur and carbon. Further, oxygen mobility may also be enhanced by elemental exchange of promoters at sites in the pyrochlore. The pyrochlore catalyst material may be utilized in catalytic reforming reactions for the conversion of hydrocarbon fuels into synthesis gas (H.sub.2+CO) for fuel cells, among other uses.
Purifying hydrocarbon oils

Energy Technology Data Exchange (ETDEWEB)

Rostin, H

1938-08-11

A process is described for continuously purifying hydrocarbon oils consisting in conducting the vapors of the same at a temperature of 300 to 400/sup 0/C over the oelitic ore minette together with reducing gases in presence of steam the proportion of the reducing gases and steam being such that the sulfur of the hydrocarbons escapes from the reaction chamber in the form of sulfuretted hydrogen without permanent sulfide of iron being formed.
Conversion of tritiated hydrogen to tritiated water on heated metal surfaces

International Nuclear Information System (INIS)

Dickson, R.S.

1993-05-01

The conversion of tritium to tritiated water on metal surfaces was studied under conditions relevant to releases into a fusion reactor hall (metal temperatures between 473 K and 623 K, air or inert gas atmospheres). The rate constant of oxidation per unit geometric surface area was found to be about a factor of ten higher than the rate constant per unit gas adsorption surface area for H 2 to H 2 O conversion on metal oxides in excess oxygen, probably because of the roughness of the metal surfaces on a gas adsorption scale. Surface roughness and oxides were found to have a major influence on the reaction rate. The reaction exhibited a first-order dependence on Q 2 concentration. Changing the dew point of the atmosphere did not affect the rate significantly, and rate constants for most metals were independent of whether the atmosphere was argon or air. Coatings of hydrocarbon and silicone polymers did not significantly affect the reaction rate on carbon steel and ferrous metals and brass all had about the same conversion rate constant. Aluminum alloy gave about three times lower and copper in Ar gave ten times higher conversion rate constants. Based on these data, an accident scenario involving exposure of 1000 m 2 of stainless steel at 573 K to a 10 4 m 3 room would cause conversion of ca. 0.1% of the Q 2 present to Q 2 O in 24 hours, while air ingress to the torus without leakage of the tritium into the room would cause 1.2% conversion in that time. The rate values are only accurate within a multiplicative factor of three, so they should be applied cautiously in model calculations. (author). 27 refs., 4 tabs., 4 figs
Metal hydrides: an innovative and challenging conversion reaction anode for lithium-ion batteries

Directory of Open Access Journals (Sweden)

Luc Aymard

2015-08-01

Full Text Available The state of the art of conversion reactions of metal hydrides (MH with lithium is presented and discussed in this review with regard to the use of these hydrides as anode materials for lithium-ion batteries. A focus on the gravimetric and volumetric storage capacities for different examples from binary, ternary and complex hydrides is presented, with a comparison between thermodynamic prediction and experimental results. MgH2 constitutes one of the most attractive metal hydrides with a reversible capacity of 1480 mA·h·g−1 at a suitable potential (0.5 V vs Li+/Li0 and the lowest electrode polarization (2, TiH2, complex hydrides Mg2MHx and other Mg-based hydrides. The reversible conversion reaction mechanism of MgH2, which is lithium-controlled, can be extended to others hydrides as: MHx + xLi+ + xe− in equilibrium with M + xLiH. Other reaction paths—involving solid solutions, metastable distorted phases, and phases with low hydrogen content—were recently reported for TiH2 and Mg2FeH6, Mg2CoH5 and Mg2NiH4. The importance of fundamental aspects to overcome technological difficulties is discussed with a focus on conversion reaction limitations in the case of MgH2. The influence of MgH2 particle size, mechanical grinding, hydrogen sorption cycles, grinding with carbon, reactive milling under hydrogen, and metal and catalyst addition to the MgH2/carbon composite on kinetics improvement and reversibility is presented. Drastic technological improvement in order to the enhance conversion process efficiencies is needed for practical applications. The main goals are minimizing the impact of electrode volume variation during lithium extraction and overcoming the poor electronic conductivity of LiH. To use polymer binders to improve the cycle life of the hydride-based electrode and to synthesize nanoscale composite hydride can be helpful to address these drawbacks. The development of high-capacity hydride anodes should be inspired by the emergent
Metal hydrides: an innovative and challenging conversion reaction anode for lithium-ion batteries.

Science.gov (United States)

Aymard, Luc; Oumellal, Yassine; Bonnet, Jean-Pierre

2015-01-01

The state of the art of conversion reactions of metal hydrides (MH) with lithium is presented and discussed in this review with regard to the use of these hydrides as anode materials for lithium-ion batteries. A focus on the gravimetric and volumetric storage capacities for different examples from binary, ternary and complex hydrides is presented, with a comparison between thermodynamic prediction and experimental results. MgH2 constitutes one of the most attractive metal hydrides with a reversible capacity of 1480 mA·h·g(-1) at a suitable potential (0.5 V vs Li(+)/Li(0)) and the lowest electrode polarization (lithium are subsequently detailed for MgH2, TiH2, complex hydrides Mg2MH x and other Mg-based hydrides. The reversible conversion reaction mechanism of MgH2, which is lithium-controlled, can be extended to others hydrides as: MH x + xLi(+) + xe(-) in equilibrium with M + xLiH. Other reaction paths-involving solid solutions, metastable distorted phases, and phases with low hydrogen content-were recently reported for TiH2 and Mg2FeH6, Mg2CoH5 and Mg2NiH4. The importance of fundamental aspects to overcome technological difficulties is discussed with a focus on conversion reaction limitations in the case of MgH2. The influence of MgH2 particle size, mechanical grinding, hydrogen sorption cycles, grinding with carbon, reactive milling under hydrogen, and metal and catalyst addition to the MgH2/carbon composite on kinetics improvement and reversibility is presented. Drastic technological improvement in order to the enhance conversion process efficiencies is needed for practical applications. The main goals are minimizing the impact of electrode volume variation during lithium extraction and overcoming the poor electronic conductivity of LiH. To use polymer binders to improve the cycle life of the hydride-based electrode and to synthesize nanoscale composite hydride can be helpful to address these drawbacks. The development of high-capacity hydride anodes should
Catalytic conversion of alcohols having at least three carbon atoms to hydrocarbon blendstock

Science.gov (United States)

Narula, Chaitanya K.; Davison, Brian H.

2015-11-13

A method for producing a hydrocarbon blendstock, the method comprising contacting at least one saturated acyclic alcohol having at least three and up to ten carbon atoms with a metal-loaded zeolite catalyst at a temperature of at least 100°C and up to 550°C, wherein the metal is a positively-charged metal ion, and the metal-loaded zeolite catalyst is catalytically active for converting the alcohol to the hydrocarbon blendstock, wherein the method directly produces a hydrocarbon blendstock having less than 1 vol % ethylene and at least 35 vol % of hydrocarbon compounds containing at least eight carbon atoms.
Catalytic conversion of alcohols having at least three carbon atoms to hydrocarbon blendstock

Science.gov (United States)

Narula, Chaitanya K.; Davison, Brian H.

2018-04-17

A method for producing a hydrocarbon blendstock, the method comprising contacting at least one saturated acyclic alcohol having at least three and up to ten carbon atoms with a metal-loaded zeolite catalyst at a temperature of at least 100.degree. C. and up to 550.degree. C., wherein the metal is a positively-charged metal ion, and the metal-loaded zeolite catalyst is catalytically active for converting the alcohol to the hydrocarbon blendstock, wherein the method directly produces a hydrocarbon blendstock having less than 1 vol % ethylene and at least 35 vol % of hydrocarbon compounds containing at least eight carbon atoms.
Natural gas conversion new route using halogen derivatives; Nova rota de conversao de gas natural utilizando derivados halogenados

Energy Technology Data Exchange (ETDEWEB)

Noronha, Leandro A.; Mota, Claudio J.A. [Universidade Federal, Rio de Janeiro, RJ (Brazil). Centro de Tecnologia]. E-mail: noronha@iq.ufrj.br; Sousa Aguiar, E. Falabella [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil). Centro de Pesquisas

2003-07-01

Natural gas will have important position in the next decades. Nowadays, there is high demand for petrochemicals products, such as ethene and propene. With the nafta price variation, the development of alternative routes from natural gas will be stimulate, as occur in Rio de Janeiro. Between the main technologies for the natural gas use, arise the gas to liquids (GTL) routes for the conversion to hydrocarbons. Therefore, will be studied the transformation of methyl chloride to light olefins (ethene and propene) and other hydrocarbons in zeolitic catalysts. All of these reactions will be simulate occurring in the zeolitic surface, using a cluster that represents very much the catalyst structure. (author)

High-pressure vapor-phase hydrodeoxygenation of lignin-derived oxygenates to hydrocarbons by a PtMo bimetallic catalyst: Product selectivity, reaction pathway, and structural characterization

Energy Technology Data Exchange (ETDEWEB)

Yohe, Sara L.; Choudhari, Harshavardhan J.; Mehta, Dhairya D.; Dietrich, Paul J.; Detwiler, Michael D.; Akatay, Cem M.; Stach, Eric A.; Miller, Jeffrey T.; Delgass, W. Nicholas; Agrawal, Rakesh; Ribeiro, Fabio H.

2016-12-01

High-pressure, vapor-phase, hydrodeoxygenation (HDO) reactions of dihydroeugenol (2-methoxy-4-propylphenol), as well as other phenolic, lignin-derived compounds, were investigated over a bimetallic platinum and molybdenum catalyst supported on multi-walled carbon nanotubes (5%Pt2.5%Mo/MWCNT). Hydrocarbons were obtained in 100% yield from dihydroeugenol, including 98% yield of the hydrocarbon propylcyclohexane. The final hydrocarbon distribution was shown to be a strong function of hydrogen partial pressure. Kinetic analysis showed three main dihydroeugenol reaction pathways: HDO, hydrogenation, and alkylation. The major pathway occurred via Pt catalyzed hydrogenation of the aromatic ring and methoxy group cleavage to form 4-propylcyclohexanol, then Mo catalyzed removal of the hydroxyl group by dehydration to form propylcyclohexene, followed by hydrogenation of propylcyclohexene on either the Pt or Mo to form the propylcyclohexane. Transalkylation by the methoxy group occurred as a minor side reaction. Catalyst characterization techniques including chemisorption, scanning transmission electron microscopy, X-ray absorption spectroscopy, and X-ray photoelectron spectroscopy were employed to characterize the catalyst structure. Catalyst components identified were Pt particles, bimetallic PtMo particles, a Mo carbide-like phase, and Mo oxide phases.
Method for upgrading diene-containing hydrocarbon mixtures

Energy Technology Data Exchange (ETDEWEB)

Kidwell, L.E. Jr.; Holcomb, D.E.

1984-05-22

There is disclosed a method for upgrading of hydrocarbon mixtures, so as to reduce their content of gum precursors such as diolefins and pseudo-diolefins, and provide a resulting product mixture suitable for mild hydrogenation, for use as a motor fuel or as a feed stock to an extraction unit. The process comprises obtaining a hydrocarbon mixture containing about 60-90 wt. % of aromatic components, about 3-40 wt. % of dienes and pseudodienes, and monoolefins, and up to about 6 wt. % of relatively unreactive organic compounds, reacting this mixture with elemental sulfur in the approximate weight ratio of about 5-95 wt. % of the hydrocarbon mixture with about 95-5 wt. % of elemental sulfur, the reaction being carried out at a temperature in the range of 100/sup 0/-150/sup 0/ C. for about 10 minutes to 24 hours with good mixing, removing the unreacted materials by distillation and separating a sulfur-hydrocarbon reaction product to provide the upgraded hydrocarbon mixture.
Effect of hydrocarbons on plasma treatment of NOx

Energy Technology Data Exchange (ETDEWEB)

Penetrante, B.M.; Pitz, W.J.; Hsaio, M.C.; Merritt, B.T.; Vogtlin, G.E. [Lawrence Livermore National Lab., CA (United States)

1997-12-31

Lean burn gasoline engine exhausts contain a significant amount of hydrocarbons in the form of propene. Diesel engine exhausts contain little gaseous hydrocarbon; however, they contain a significant amount of liquid-phase hydrocarbons (known as the volatile organic fraction) in the particulates. The objective of this paper is to examine the fate of NO{sub x} when an exhaust gas mixture that contains hydrocarbons is subjected to a plasma. The authors will show that the hydrocarbons promote the oxidation of NO to NO{sub 2}, but not the reduction of NO to N{sub 2}. The oxidation of NO to NO{sub 2} is strongly coupled with the hydrocarbon oxidation chemistry. This result suggests that gas-phase reactions in the plasma alone cannot lead to the chemical reduction of NO{sub x}. Any reduction of NO{sub x} to N{sub 2} can only be accomplished through heterogeneous reactions of NO{sub 2} with surfaces or particulates.
Thermal conversion of waste polyolefins to the mixture of hydrocarbons in the reactor with molten metal bed

Energy Technology Data Exchange (ETDEWEB)

Stelmachowski, M. [Department of Environmental Engineering, Faculty of Process and Environmental Engineering, Technical University of Lodz, 90-924 Lodz, Wolczanska 213 (Poland)

2010-10-15

Energy crisis and environmental degradation by polymer wastes have been imperative to find and propose technologies for recovery of raw materials and energy from non-conventional sources like organic wastes, plastic wastes, scrap tires, etc. A variety of methods and processes connected with global or national policies have been proposed worldwide. A new type of a tubular reactor with the molten metal bed is proposed for conversion of waste plastics to fuel-like mixture of hydrocarbons. The results of the thermal degradation of polyolefins in the laboratory scale set-up based on this reactor are presented in the paper. The melting and cracking processes were carried out in a single apparatus at the temperature 390-420 C. The problems with: disintegration of wastes, heat transfer from the wall to the particles of polymers, cooking at the walls of reactor, and mixing of the molten volume of wastes were significantly reduced. The final product consisted of gaseous stream (8-16 wt% of the input) and liquid (84-92 wt%) stream. No solid products were produced. The light, ''gasoline'' fraction of the liquid hydrocarbons mixture (C{sub 4}-C{sub 10}) made over 50% of the liquid product. It may by used for fuel production or electricity generation. (author)
Thermal conversion of waste polyolefins to the mixture of hydrocarbons in the reactor with molten metal bed

International Nuclear Information System (INIS)

Stelmachowski, M.

2010-01-01

Energy crisis and environmental degradation by polymer wastes have been imperative to find and propose technologies for recovery of raw materials and energy from non-conventional sources like organic wastes, plastic wastes, scrap tires, etc. A variety of methods and processes connected with global or national policies have been proposed worldwide. A new type of a tubular reactor with the molten metal bed is proposed for conversion of waste plastics to fuel like mixture of hydrocarbons. The results of the thermal degradation of polyolefins in the laboratory scale set-up based on this reactor are presented in the paper. The melting and cracking processes were carried out in a single apparatus at the temperature 390-420 deg. C. The problems with: disintegration of wastes, heat transfer from the wall to the particles of polymers, cooking at the walls of reactor, and mixing of the molten volume of wastes were significantly reduced. The final product consisted of gaseous stream (8-16 wt% of the input) and liquid (84-92 wt%) stream. No solid products were produced. The light, 'gasoline' fraction of the liquid hydrocarbons mixture (C 4 -C 10 ) made over 50% of the liquid product. It may by used for fuel production or electricity generation.
Modification of the performance of WO{sub 3}-ZrO{sub 2} catalysts by metal addition in hydrocarbon reactions

Energy Technology Data Exchange (ETDEWEB)

Torres, Gerardo Carlos; Manuale, Debora Laura; Benitez, Viviana Monica; Vera, Carlos Roman; Yori, Juan Carlos, E-mail: jyori@fiq.unl.edu.ar [Instituto de Investigaciones en Catalisis y Petroquimica, Facultad de Ingenieria Quimica, Universidad Nacional del Litoral, Consejo Nacional de Investigaciones Cientifica y Tecnicas, Santiago del Estero Santa Fe (Argentina)

2012-07-01

A study of the different hydrocarbon reactions over Ni doped WO{sub 3}-ZrO{sub 2} catalysts was performed. Ni was found as NiO at low Ni concentration while at high Ni concentrations a small fraction was present as a metal. For both cases, Ni strongly modified total acidity and concentration of strong acid sites. In the cyclohexane dehydrogenation reaction, Ni addition promotes both benzene and methyl cyclopentane production. The hydroconversion activity (n-butane and n-octane) increases with the augment of total acidity produced by Ni. The selectivity to reaction products is modified according to the acid strength distribution changes produced by Ni addition. (author)
Influence of the Reaction Temperature on the Nature of the Active and Deactivating Species during Methanol to Olefins Conversion over H-SSZ-13

NARCIS (Netherlands)

Borodina, E.; Meirer, F.; Lezcano-Gonzalez, I.; Mokhtar, M.; Asiri, A. M.; Al-Thabaiti, S. A.; Basahel, S. N.; Ruiz-Martinez, J.; Weckhuysen, B. M.

The formation of hydrocarbon species during the methanol to olefins (MTO) reaction over zeolite H-SSZ-13 has been systematically studied at reaction temperatures between 573 and 723 K with a combination of operando UV-vis spectroscopy and online gas chromatography. It was found that the applied
Nonthermal plasma reactors for the production of light hydrocarbon olefins from heavy oil

Directory of Open Access Journals (Sweden)

G. Prieto

2003-03-01

Full Text Available During the last decade, nonthermal plasma technology was applied in many different fields, focusing attention on the destruction of harmful compounds in the air. This paper deals with nonthermal plasma reactors for the conversion of heavy oil into light hydrocarbon olefins, to be employed as gasoline components or to be added in small amounts for the catalytic reduction of nitrogen oxide compounds in the treatment of exhaust gas at power plants. For the process, the plate-plate nonthermal plasma reactor driven by AC high voltage was selected. The reactor was modeled as a function of parameter characteristics, using the methodology provided by the statistical experimental design. The parameters studied were gap distance between electrodes, carrier gas flow and applied power. Results indicate that the reactions occurring in the process of heavy oil conversion have an important selective behavior. The products obtained were C1-C4 hydrocarbons with ethylene as the main compound. Operating the parameters of the reactor within the established operative window of the system and close to the optimum conditions, efficiencies as high as 70 (mul/joule were obtained. These values validate the process as an in-situ method to produce light olefins for the treatment of nitrogen oxides in the exhaust gas from diesel engines.
Production of hydrogen via conversion of hydrocarbons using a microwave plasma

International Nuclear Information System (INIS)

Jasinski, Mariusz; Dors, Miroslaw; Nowakowska, Helena; Mizeraczyk, Jerzy; Nichipor, Gerietta V

2011-01-01

In this paper, results of hydrogen production from hydrocarbons in an atmospheric pressure microwave plasma are presented. As sources of hydrogen, both methane CH 4 and tetrafluoroethane C 2 H 2 F 4 were tested. A new waveguide-based nozzleless cylinder-type microwave plasma source was used to convert hydrocarbons into hydrogen. The processed gaseous hydrocarbons were introduced into the plasma by four gas ducts which formed a swirl flow in the plasma reactor. The absorbed microwave power was up to 5 kW. The gas flow rate was up to 212 L min -1 . The hydrogen mass yield rate and the corresponding energetic hydrogen mass yield were up to 866 g[H 2 ] h -1 and 577 g [H 2 ] kWh -1 of microwave energy absorbed by the plasma, respectively. These parameters are better than our previous results when nitrogen was used as a swirl gas and much better than those typical for other plasma methods of hydrogen production (electron beam, gliding arc, plasmatron).
Effects of hydrocarbon contamination on ozone generation with dielectric barrier discharges

Science.gov (United States)

Lopez, Jose L.; Vezzu, Guido; Freilich, Alfred; Paolini, Bernhard

2013-08-01

The increasing usage of the feed gases of lower grade liquid oxygen (LOX) containing higher levels of trace hydrocarbon impurities in dielectric barrier discharge (DBD) for ozone generation requires a better understanding of the kinetics of the by-product formation resulting from reactions involving these hydrocarbon impurities. As a case study of hydrocarbon impurities, the kinetics of CH4 conversion in DBDs and the subsequent HNO3 formation were investigated by means of gas-phase plasma diagnostics, supported by detailed process modeling, and extensive in-situ and ex-situ by-product analysis. The by-products formation in the plasma with the presence of CH4, were found to differ significantly in oxygen-fed generators as compared to generators fed with oxygen/nitrogen mixtures. The amount of HNO3 formed depends on the concentration of NOx formed in the plasma and the amount of CH4 that is converted, but not on the O3 concentration. In the present work we have investigated CH4 concentrations of up to 1.95 wt% of the feed gas. The rate of deterioration of the overall ozone generator performance was found to be affected by the concentration of nitrogen in the oxygen/nitrogen mixture.
Task 3.3: Warm Syngas Cleanup and Catalytic Processes for Syngas Conversion to Fuels Subtask 3: Advanced Syngas Conversion to Fuels

Energy Technology Data Exchange (ETDEWEB)

Lebarbier Dagel, Vanessa M.; Li, J.; Taylor, Charles E.; Wang, Yong; Dagle, Robert A.; Deshmane, Chinmay A.; Bao, Xinhe

2014-03-31

activity was to develop methods and enabling materials for syngas conversion to SNG with readily CO2 separation. Suitable methanation catalyst and CO2 sorbent materials were developed. Successful proof-of-concept for the combined reaction-sorption process was demonstrated, which culminated in a research publication. With successful demonstration, a decision was made to switch focus to an area of fuels research of more interest to all three research institutions (CAS-NETL-PNNL). Syngas-to-Hydrocarbon Fuels through Higher Alcohol Intermediates There are two types of processes in syngas conversion to fuels that are attracting R&D interest: 1) syngas conversion to mixed alcohols; and 2) syngas conversion to gasoline via the methanol-to-gasoline process developed by Exxon-Mobil in the 1970s. The focus of this task was to develop a one-step conversion technology by effectively incorporating both processes, which is expected to reduce the capital and operational cost associated with the conversion of coal-derived syngas to liquid fuels. It should be noted that this work did not further study the classic Fischer-Tropsch reaction pathway. Rather, we focused on the studies for unique catalyst pathways that involve the direct liquid fuel synthesis enabled by oxygenated intermediates. Recent advances made in the area of higher alcohol synthesis including the novel catalytic composite materials recently developed by CAS using base metal catalysts were used.
Modeling of the interplay between single-file diffusion and conversion reaction in mesoporous systems

Energy Technology Data Exchange (ETDEWEB)

Wang, Jing [Iowa State Univ., Ames, IA (United States)

2013-01-11

We analyze the spatiotemporal behavior of species concentrations in a diffusion-mediated conversion reaction which occurs at catalytic sites within linear pores of nanometer diameter. A strict single-file (no passing) constraint occurs in the diffusion within such narrow pores. Both transient and steady-state behavior is precisely characterized by kinetic Monte Carlo simulations of a spatially discrete lattice–gas model for this reaction–diffusion process considering various distributions of catalytic sites. Exact hierarchical master equations can also be developed for this model. Their analysis, after application of mean-field type truncation approximations, produces discrete reaction–diffusion type equations (mf-RDE). For slowly varying concentrations, we further develop coarse-grained continuum hydrodynamic reaction–diffusion equations (h-RDE) incorporating a precise treatment of single-file diffusion (SFD) in this multispecies system. Noting the shortcomings of mf-RDE and h-RDE, we then develop a generalized hydrodynamic (GH) formulation of appropriate gh-RDE which incorporates an unconventional description of chemical diffusion in mixed-component quasi-single-file systems based on a refined picture of tracer diffusion for finite-length pores. The gh-RDE elucidate the non-exponential decay of the steady-state reactant concentration into the pore and the non-mean-field scaling of the reactant penetration depth. Then an extended model of a catalytic conversion reaction within a functionalized nanoporous material is developed to assess the effect of varying the reaction product – pore interior interaction from attractive to repulsive. The analysis is performed utilizing the generalized hydrodynamic formulation of the reaction-diffusion equations which can reliably capture the complex interplay between reaction and restricted transport for both irreversible and reversible reactions.
Investigation of Thermochemistry Associated with the Carbon–Carbon Coupling Reactions of Furan and Furfural Using ab Initio Methods

Energy Technology Data Exchange (ETDEWEB)

Liu, Cong; Assary, Rajeev S.; Curtiss, Larry A.

2014-06-26

Upgrading of furan and small oxygenates obtained from the decomposition of cellulosic materials via formation of carbon-carbon bonds is critical to effective conversion of biomass to liquid transportation fuels. Simulation-driven molecular level understanding of carbon-carbon bond formation is required to design efficient catalysts and processes. Accurate quantum chemical methods are utilized here to predict the reaction energetics for conversion of furan (C4H4O) to C5-C8 ethers and the transformation of furfural (C5H6O2) to C13-C26 alkanes. Furan, can be coupled with various C1 to C4 lower molecular weight carbohydrates obtained from the pyrolysis via Diels-Alder type reactions in the gas phase to produce C5-C8 cyclic ethers. The computed reaction barriers for these reactions (~25 kcal/mol) are lower than the cellulose activation or decomposition reactions (~50 kcal/mol). Cycloaddition of C5-C8 cyclo-ethers with furans can also occur in the gas phase, and the computed activation energy is similar to that of the first Diels-Alder reaction. Furfural, obtained from biomass, can be coupled with aldehydes or ketones with α-hydrogen atoms to form longer chain aldol products and these aldol products can undergo vapor phase hydrocycloaddition (activation barrier of ~20 kcal/mol) to form the precursors of C26 cyclic hydrocarbons. These thermochemical studies provide the basis for further vapor phase catalytic studies required for upgrading of furans/furfurals to longer chain hydrocarbons.
Production of hydrogen via conversion of hydrocarbons using a microwave plasma

Energy Technology Data Exchange (ETDEWEB)

Jasinski, Mariusz; Dors, Miroslaw; Nowakowska, Helena; Mizeraczyk, Jerzy [Centre for Plasma and Laser Engineering, The Szewalski Institute of Fluid-Flow Machinery, Polish Academy of Sciences, Fiszera 14, 80-952 Gdansk (Poland); Nichipor, Gerietta V, E-mail: mj@imp.gda.pl [Joint Institute of Power and Nuclear Research, Academy of Sciences of Belarus, Minsk, Sosny 220109 (Belarus)

2011-05-18

In this paper, results of hydrogen production from hydrocarbons in an atmospheric pressure microwave plasma are presented. As sources of hydrogen, both methane CH{sub 4} and tetrafluoroethane C{sub 2}H{sub 2}F{sub 4} were tested. A new waveguide-based nozzleless cylinder-type microwave plasma source was used to convert hydrocarbons into hydrogen. The processed gaseous hydrocarbons were introduced into the plasma by four gas ducts which formed a swirl flow in the plasma reactor. The absorbed microwave power was up to 5 kW. The gas flow rate was up to 212 L min{sup -1}. The hydrogen mass yield rate and the corresponding energetic hydrogen mass yield were up to 866 g[H{sub 2}] h{sup -1} and 577 g [H{sub 2}] kWh{sup -1} of microwave energy absorbed by the plasma, respectively. These parameters are better than our previous results when nitrogen was used as a swirl gas and much better than those typical for other plasma methods of hydrogen production (electron beam, gliding arc, plasmatron).
Biomass thermochemical conversion program: 1987 annual report

Energy Technology Data Exchange (ETDEWEB)

Schiefelbein, G.F.; Stevens, D.J.; Gerber, M.A.

1988-01-01

The objective of the Biomass Thermochemical Conversion Program is to generate a base of scientific data and conversion process information that will lead to establishment of cost-effective processes for conversion of biomass resources into clean fuels. To accomplish this objective, in fiscal year 1987 the Thermochemical Conversion Program sponsored research activities in the following four areas: Liquid Hydrocarbon Fuels Technology; Gasification Technology; Direct Combustion Technology; Program Support Activities. In this report an overview of the Thermochemical Conversion Program is presented. Specific research projects are then described. Major accomplishments for 1987 are summarized.
Plasma-catalytic reforming of liquid hydrocarbons

International Nuclear Information System (INIS)

Nedybaliuk, O.A.; Chernyak, V.Ya; Kolgan, V.V.; Iukhymenko, V.V.; Solomenko, O.V.; Fedirchyk, I.I.; Martysh, E.V.; Demchina, V.P.; Klochok, N.V.; Dragnev, S.V.

2015-01-01

The series of experiments studying the plasma-catalytic reforming of liquid hydrocarbons was carried out. The dynamic plasma-liquid system based on a low-power rotating gliding arc with solid electrodes was used for the investigation of liquid hydrocarbons reforming process. Conversion was done via partial oxidation. A part of oxidant flow was activated by the discharge. Synthesis-gas composition was analysed by means of mass-spectrometry and gas-chromatography. A standard boiler, which operates on natural gas and LPG, was used for the burning of synthesis-gas
Formation of Nitriles in the Interstellar Medium via Reactions of Cyano Radicals, CN(X2Σ+), with Unsaturated Hydrocarbons

Science.gov (United States)

Balucani, N.; Asvany, O.; Huang, L. C. L.; Lee, Y. T.; Kaiser, R. I.; Osamura, Y.; Bettinger, H. F.

2000-12-01

Crossed molecular beam experiments of cyano radicals, CN(X2Σ+, ν=0), in their electronic and vibrational ground state reacting with unsaturated hydrocarbons acetylene, C2H2(X1Σ+g), ethylene, C2H4(X1Ag), methylacetylene, CH3CCH(X1A1), allene, H2CCCH2(X1A1), dimethylacetylene, CH3CCCH3(X1A1'), and benzene, C6H6 (X1A1g), were performed at relative collision energies between 13.3 and 36.4 kJ mol-1 to unravel the formation of unsaturated nitriles in the outflows of late-type AGB carbon stars and molecular clouds. In all reactions, the CN radical was found to attack the π electron density of the hydrocarbon molecule with the radical center located at the carbon atom; the formation of an initial addition complex is a prevalent pathway on all the involved potential energy surfaces. A subsequent carbon-hydrogen bond rupture yields the nitriles cyanoacetylene, HCCCN (X1Σ+), vinylcyanide, C2H3CN (X1A'), 1-methylcyanoacetylene, CH3CCCN (X1A1), cyanoallene, H2CCCH(CN) (X1A'), 3-methylcyanoacetylene, HCCCH2CN(X1A'), 1,1-cyanomethylallene, H2CCC(CN)(CH3) (X1A'), and cyanobenzene, C6H5CN (X1A1). In case of acetylene and ethylene, a second reaction channel involves a [1, 2]-H atom shift in the initial HCCHCN and H2CCH2CN collision complexes prior to a hydrogen atom release to form cyanoacetylene, HCCCN (X1Σ+), and vinylcyanide, C2H3CN (X1A'). Since all these radical-neutral reactions show no entrance barriers, have exit barriers well below the energy of the reactant molecules, and are exothermic, the explicit identification of this CN versus H atom exchange pathway under single collision conditions makes this reaction class a compelling candidate to synthesize unsaturated nitriles in interstellar environments holding temperatures as low as 10 K. This general concept makes it even feasible to predict the formation of nitriles once the corresponding unsaturated hydrocarbons are identified in the interstellar medium. Here HCCCN, C2H3CN, and CH3CCCN have been already observed
Integration of direct carbon and hydrogen fuel cells for highly efficient power generation from hydrocarbon fuels

Energy Technology Data Exchange (ETDEWEB)

Muradov, Nazim; Choi, Pyoungho; Smith, Franklyn; Bokerman, Gary [Florida Solar Energy Center, University of Central Florida, 1679 Clearlake Road, Cocoa, FL 32922-5703 (United States)

2010-02-15

In view of impending depletion of hydrocarbon fuel resources and their negative environmental impact, it is imperative to significantly increase the energy conversion efficiency of hydrocarbon-based power generation systems. The combination of a hydrocarbon decomposition reactor with a direct carbon and hydrogen fuel cells (FC) as a means for a significant increase in chemical-to-electrical energy conversion efficiency is discussed in this paper. The data on development and operation of a thermocatalytic hydrocarbon decomposition reactor and its coupling with a proton exchange membrane FC are presented. The analysis of the integrated power generating system including a hydrocarbon decomposition reactor, direct carbon and hydrogen FC using natural gas and propane as fuels is conducted. It was estimated that overall chemical-to-electrical energy conversion efficiency of the integrated system varied in the range of 49.4-82.5%, depending on the type of fuel and FC used, and CO{sub 2} emission per kW{sub el}h produced is less than half of that from conventional power generation sources. (author)
Theoretical Studies of Elementary Hydrocarbon Species and Their Reactions

Energy Technology Data Exchange (ETDEWEB)

Allen, Wesley D. [University of Georgia, Department of Chemistry and Center for Computational Quantum Chemistry; Schaefer, Henry F. [University of Georgia, Center for Computational Quantum Chemistry

2018-04-08

The research program supported by this DOE grant carried out both methodological development and computational applications of first-principles theoretical chemistry based on quantum mechanical wavefunctions, as directed toward understanding and harnessing the fundamental chemical physics of combustion. To build and refine the world’s database of thermochemistry, spectroscopy, and chemical kinetics, predictive and definitive computational methods are needed that push the envelope of modern electronic structure theory. The application of such methods has been made to gain comprehensive knowledge of the paradigmatic reaction networks by which the n- and i-propyl, t-butyl, and n-butyl radicals are oxidized by O₂. Numerous ROO and QOOH intermediates in these R + O₂ reaction systems have been characterized along with the interconnecting isomerization transition states and the barriers leading to fragmentation. Other combustion-related intermediates have also been studied, including methylsulfinyl radical, cyclobutylidene, and radicals derived from acetaldehyde and vinyl alcohol. Theoretical advances have been achieved and made available to the scientific community by implementation into PSI4, an open-source electronic structure computer package emphasizing automation, advanced libraries, and interoperability. We have pursued the development of universal explicitly correlated methods applicable to general electronic wavefunctions, as well as a framework that allows multideterminant reference functions to be expressed as a single determinant from quasiparticle operators. Finally, a rigorous analytical tool for correlated wavefunctions has been created to elucidate dispersion interactions, which play essential roles in many areas of chemistry, but whose effects are often masked and enigmatic. Our research decomposes and analyzes the coupled-cluster electron correlation energy in molecular systems as a function of interelectronic distance. Concepts
A parametric duration model of the reaction times of drivers distracted by mobile phone conversations.

Science.gov (United States)

Haque, Md Mazharul; Washington, Simon

2014-01-01

The use of mobile phones while driving is more prevalent among young drivers-a less experienced cohort with elevated crash risk. The objective of this study was to examine and better understand the reaction times of young drivers to a traffic event originating in their peripheral vision whilst engaged in a mobile phone conversation. The CARRS-Q advanced driving simulator was used to test a sample of young drivers on various simulated driving tasks, including an event that originated within the driver's peripheral vision, whereby a pedestrian enters a zebra crossing from a sidewalk. Thirty-two licensed drivers drove the simulator in three phone conditions: baseline (no phone conversation), hands-free and handheld. In addition to driving the simulator each participant completed questionnaires related to driver demographics, driving history, usage of mobile phones while driving, and general mobile phone usage history. The participants were 21-26 years old and split evenly by gender. Drivers' reaction times to a pedestrian in the zebra crossing were modelled using a parametric accelerated failure time (AFT) duration model with a Weibull distribution. Also tested where two different model specifications to account for the structured heterogeneity arising from the repeated measures experimental design. The Weibull AFT model with gamma heterogeneity was found to be the best fitting model and identified four significant variables influencing the reaction times, including phone condition, driver's age, license type (provisional license holder or not), and self-reported frequency of usage of handheld phones while driving. The reaction times of drivers were more than 40% longer in the distracted condition compared to baseline (not distracted). Moreover, the impairment of reaction times due to mobile phone conversations was almost double for provisional compared to open license holders. A reduction in the ability to detect traffic events in the periphery whilst distracted

Kinetic particularities of strained alicyclic compounds formation in catalytic methanol to hydrocarbon transformation process

OpenAIRE

Doluda V.; Brovko R.; Giniatullina N.; Sulman M.

2017-01-01

The catalytic transformation of methanol into hydrocarbons is a complex chemical process, accompanied by chain parallel chemical transformation reactions. The most valuable products of the methanol to hydrocarbons catalytic transformation reaction are the strained hydrocarbons — cyclopropane derivatives. These compounds can be used as a high-energy fuel, and also as a valuable chemical raw material. However, the yield of strained compounds in methanol to hydrocarbons catalytic transformation ...
Renewable energy based catalytic CH4 conversion to fuels

NARCIS (Netherlands)

Baltrusaitis, Jonas; Jansen, I.; Schuttlefield, J.D.S.

2014-01-01

Natural gas is envisioned as a primary source of hydrocarbons in the foreseeable future. With the abundance of shale gas, the main concerns have shifted from the limited hydrocarbon availability to the sustainable methods of CH4 conversion to fuels. This is necessitated by high costs of natural gas
Radiolysis of hydrocarbons in liquid phase (Modern state of problem)

International Nuclear Information System (INIS)

Saraeva, V.V.

1986-01-01

Problems of ionizing radiation effect on hydrocarbons and hydrocarbon systems in a liquid phase are considered. Modern representations on the mechanism of hydrocarbon radiolysis are presented. Electron moderation and ion-electron pair formation, behaviour of charged particles, excited states, radical formation and their reactions are discussed. Behaviour of certain hydrocarbon classes: alkanes, cyclic hydrocarbons, olefines, aromatic hydrocarbons as well as different hydrocarbon mixtures is considered in detail. Radiation-chemical changes in organic coolants and ways of increasing radiation resistance are considered. Polyphenyl compounds are noted to be most perspective here
Radioactive (14C) tracer studies of methanol conversion over a Ni-ZSM-5 zeolite

International Nuclear Information System (INIS)

Hwu, F.S.; Hightower, J.W.

1983-01-01

Secondary reactions have been identified in the overall conversion of methanol to hydrocarbons over a Ni-ZSM-5 catalyst. The major conclusions are: (1) The alkylation of light olefins with methanol or methyl ether is one pathway for the formation of larger olefins with one more carbon atom. (2) Paraffins are produced primarily by hydrogen transfer to the corresponding olefin. (3) Except for minor cracking reactions, paraffins with no more than 7 carbon atoms, are final stable products; isomerization among paraffin isomers does not take place at 368 0 C. (4) Light olefins, e.g. ethylene, propylene, and butenes, are reactive intermediates for aromatics formation. (5) Aromatic compounds may also be produced by methanol- methyl ether-alkylation of benzene and subsequent alkylated benezenes. 2 figures, 3 tables
A reaction mechanism for gasoline surrogate fuels for large polycyclic aromatic hydrocarbons

KAUST Repository

Raj, Abhijeet

2012-02-01

This work aims to develop a reaction mechanism for gasoline surrogate fuels (n-heptane, iso-octane and toluene) with an emphasis on the formation of large polycyclic aromatic hydrocarbons (PAHs). Starting from an existing base mechanism for gasoline surrogate fuels with the largest chemical species being pyrene (C 16H 10), this new mechanism is generated by adding PAH sub-mechanisms to account for the formation and growth of PAHs up to coronene (C 24H 12). The density functional theory (DFT) and the transition state theory (TST) have been adopted to evaluate the rate constants for several PAH reactions. The mechanism is validated in the premixed laminar flames of n-heptane, iso-octane, benzene and ethylene. The characteristics of PAH formation in the counterflow diffusion flames of iso-octane/toluene and n-heptane/toluene mixtures have also been tested for both the soot formation and soot formation/oxidation flame conditions. The predictions of the concentrations of large PAHs in the premixed flames having available experimental data are significantly improved with the new mechanism as compared to the base mechanism. The major pathways for the formation of large PAHs are identified. The test of the counterflow diffusion flames successfully predicts the PAH behavior exhibiting a synergistic effect observed experimentally for the mixture fuels, irrespective of the type of flame (soot formation flame or soot formation/oxidation flame). The reactions that lead to this synergistic effect in PAH formation are identified through the rate-of-production analysis. © 2011 The Combustion Institute.
Conversion of polycyclic aromatic hydrocarbons on diesel particulate matter upon exposure to ppm levels of ozone

Science.gov (United States)

Van Vaeck, L.; Van Cauwenberghe, K.

Diesel exhaust particlulate matter samples were collected from a dilution tunnel using a Hi-Vol cascade impactor. The fraction of the aerosol with aerodynamic diameter below 0.5 μm, retained on the glass fiber back-up filter, was exposed to a flow of ozonised particle free air for periods of 0.5-4 h (1.5 ppm of O 3, flow rate about 40 m 3 h -1). Both exposed and non-exposed reference niters were Soxhlet-extracted with benzene and methanol, and the polycyclic aromatic hydrocarbon fraction (PAH) was isolated by a liquid-liquid partition procedure described in the literature, using cyclohexane and dimethylformamid-water as solvents, modified for quantitative recovery of PAH. The conversion yields of PAH upon exposure to O 3 were determined by single ion monitoring mass spectrometry using a fused silica capillary column for their separation. Significant conversion was observed for PAH from molecular weight 226 to 276. Approximate half lives are of the order of 0.5-1 h for most PAH measured. This high reactivity of PAH on a carbonaceous matrix is probably related to the large specific surface of soot particles as well as to their high adsorptive capacity for gaseous compounds. Lower molecular weight PAH up to chrysene also undergo important physical losses by volatilisation and the extent to which chemical transformations occurred could not be determined accurately. Different reactivities are observed for several isomeric pairs of PAH: benzo(a)pyrene is much faster converted than benzo(e)pyrene, benz(a)anthracene reacts faster than chrysene. The benzo-fluoranthenes are most resistant toward O 3 attack. The implications of these results with respect to atmospheric degradation of PAH, as well as to the occurrence of artefactual conversion upon Hi-Vol sampling are discussed.
Preparing valuable hydrocarbons by hydrogenation

Energy Technology Data Exchange (ETDEWEB)

Pier, M

1930-08-22

A process is described for the preparation of valuable hydrocarbons by treatment of carbonaceous materials, like coal, tars, minerals oils, and their distillation and conversion products, and for refining of liquid hydrocarbon mixture obtained at raised temperature and under pressure, preferably in the presence of catalysts, by the use of hydrogen-containing gases, purified and obtained by distilling solid combustibles, characterized by the purification of the hydrogen-containing gases being accomplished for the purpose of practically complete removal of the oxygen by heating at ordinary or higher pressure in the presence of a catalyst containing silver and oxides of metals of group VI of the periodic system.
Effects of non-thermal plasmas and electric field on hydrocarbon/air flames

Science.gov (United States)

Ganguly, Biswa

2009-10-01

Need to improve fuel efficiency, and reduce emission from hydrocarbon combustor in automotive and gas turbine engines have reinvigorated interest in reducing combustion instability of a lean flame. The heat generation rate in a binary reaction is HQ =N^2 c1c2 Q exp(-E/RT), where N is the density, c1 and c2 are mol fractions of the reactants, Q is the reaction heat release, E is the activation energy, R is the gas constant and T is the average temperature. For hydrocarbon-air reactions, the typical value of E/R ˜20, so most heat release reactions are confined to a thin reaction sheet at T >=1400 K. The lean flame burning condition is susceptible to combustion instability due to a critical balance between heat generation and heat loss rates, especially at high gas flow rate. Radical injection can increase flame speed by reducing the hydrocarbon oxidation reaction activation barrier and it can improve flame stability. Advances in nonequilibrium plasma generation at high pressure have prompted its application for energy efficient radical production to enhance hydrocarbon-air combustion. Dielectric barrier discharges and short pulse excited corona discharges have been used to enhance combustion stability. Direct electron impact dissociation of hydrocarbon and O2 produces radicals with lower fuel oxidation reaction activation barriers, initiating heat release reaction CnHm+O CnHm-1+ OH (and other similar sets of reactions with partially dissociated fuel) below the typical cross-over temperature. Also, N2 (A) produced in air discharge at a moderate E/n can dissociate O2 leading to oxidation of fuel at lower gas temperature. Low activation energy reactions are also possible by dissociation of hydrocarbon CnHm+e -> CnHm-2+H2+e, where a chain propagation reaction H2+ O OH+H can be initiated at lower gas temperature than possible under thermal equilibrium kinetics. Most of heat release comes from the reaction CO+OH-> CO2 +H, nonthermal OH production seem to improve
Recovery of hydrocarbon oils

Energy Technology Data Exchange (ETDEWEB)

1941-02-10

A process is disclosed for recovery of hydrocarbon oils, especially lubricating oils or diesel oils, through pressure hydrogenation of distillation, extraction of hydrogenation products from coal or coaly materials or from oils such as mineral oils or tars in liquid phase by use in a reaction vessel of fixed-bed catalysts, characterized in that as starting material is employed material which has been freed of asphaltic and resinous material by hydrogenation refining, vacuum-steam distillation, treatment with hydrogen-rich hydrocarbons (hydroforming), or sulfuric acid.
Biomass Thermochemical Conversion Program: 1986 annual report

Energy Technology Data Exchange (ETDEWEB)

Schiefelbein, G.F.; Stevens, D.J.; Gerber, M.A.

1987-01-01

Wood and crop residues constitute a vast majority of the biomass feedstocks available for conversion, and thermochemical processes are well suited for conversion of these materials. Thermochemical conversion processes can generate a variety of products such as gasoline hydrocarbon fuels, natural gas substitutes, or heat energy for electric power generation. The US Department of Energy is sponsoring research on biomass conversion technologies through its Biomass Thermochemical Conversion Program. Pacific Northwest Laboratory has been designated the Technical Field Management Office for the Biomass Thermochemical Conversion Program with overall responsibility for the Program. This report briefly describes the Thermochemical Conversion Program structure and summarizes the activities and major accomplishments during fiscal year 1986. 88 refs., 31 figs., 5 tabs.
Co-conversion of Ethane and Methanol into Higher Hydrocarbons over Ga/H-ZSM-5, Mo/H-ZSM-5 and Ga-Mo/H-ZSM-5

DEFF Research Database (Denmark)

Mentzel, Uffe Vie; Rovik, Anne; Christensen, Claus H.

2009-01-01

Ethane and methanol are converted simultaneously over Ga/H-ZSM-5, Mo/H-ZSM-5 and Ga-Mo/H-ZSM-5 to produce light olefins and aromatics. The presence of methanol in the reactant stream is intended to facilitate activation of ethane following literature reports on co-conversion of methane and methan...... and in the carbonaceous compounds deposited on the catalysts. This indicates that both reactants take part in the formation of the hydrocarbon pool, which is the origin of all products....
Methanol to olefin Conversion on HSAPO-34 zeolite from periodic density functional theory calculations: a complete cycle of side chain hydrocarbon pool mechanism

Energy Technology Data Exchange (ETDEWEB)

Wang, C.M.; Wang, Y.D.; Xie, Z.K.; Liu, Z.P. [SINOPEC, Shanghai (China)

2009-03-15

For its unique position in the coal chemical industry, the methanol to olefin (MTO) reaction has been a hot topic in zeolite catalysis. Due to the complexities of catalyst structure and reaction networks, many questions such as how the olefin chain is built from methanol remain elusive. On the basis of periodic density functional theory calculations, this work establishes the first complete catalytic cycle for MTO reaction via hexamethylbenzene (HMB) trapped in HSAPO-34 zeolite based on the so-called side chain hydrocarbon pool mechanism. The cycle starts from the methylation of HMB that leads to heptamethylbenzenium ion (heptaMB{sup +}) intermediate. This is then followed by the growth of side chain via repeated deprotonation of benzenium ions and methylation of the exocyclic double bond. Ethene and propene can finally be released from the side ethyl and isopropyl groups of benzenium ions by deprotonation and subsequent protonation steps. We demonstrate that (i) HMB/HSAPO-34 only yields propene as the primary product based on the side chain hydrocarbon pool mechanism and (ii) an indirect proton-shift step mediated by water that is always available in the system is energetically more favorable than the traditionally regarded internal hydrogen-shift step. Finally, the implications of our results toward understanding the effect of acidity of zeolite on MTO activity are also discussed.
Direct electroreduction of CO2 into hydrocarbon

International Nuclear Information System (INIS)

Winea, Gauthier; Ledoux, Marc-Jacques; Pham-Huu, Cuong; Gangeri, Miriam; Perathoner, Siglinda; Centi, Gabriele

2006-01-01

A lot of methods exist to directly reduce carbon dioxide into hydrocarbons: the photoelectrochemical process is certainly the most interesting, essentially due to the similarities with photosynthesis. As the human activities produce a great quantity of CO 2 , this one can then be considered as an infinite source of carbon. The products of this reaction are identical to those obtained during a Fischer-Tropsch reaction, that is to say hydrocarbons, alcohols and carboxylic acids. These works deal with the electrochemical reduction of CO 2 in standard conditions of temperature and pressure. The photochemical part has been replaced by a current generator as electrons source and a KHCO 3 aqueous solution as protons source. The first catalytic results clearly show that it is possible to reduce CO 2 into light hydrocarbons, typically from C1 to C9. (O.M.)
Renewable synthesis-gas-production. Do hydrocarbons in the reactant flow of the reverse water-gas shift reaction cause coke formation?

Energy Technology Data Exchange (ETDEWEB)

Wolf, A.; Kern, C.; Jess, A. [Bayreuth Univ. (Germany). Dept. of Chemical Engineering

2013-11-01

In a two-step synthetic fuel production process based on carbon dioxide and renewable hydrogen, the best possible selectivity towards liquid hydrocarbons (Hc) shall be implemented. The process consists of a combination of the Reverse Water-Gas Shift reaction and the Fischer-Tropsch synthesis. To achieve this goal, gaseous short-chained Hc from the FTS reactor are recycled in the RWGS unit. In this paper, challenges coming up with the implementation of a recycle loop are discussed. First of all, it has to be examined whether Hc are converted under conditions present in the RWGS reactor. The coking caused by the recycle of Hc is regarded, including thermal coking in the heating zone of the reactor and catalytic coking in the catalyst bed. Coking of course is unwanted, as it deactivates the catalyst. The scope of this work is to find out to which extent and under which conditions gaseous Hc can be recycled. Therefore, experiments were carried out in both, a quartz glass reactor using a commercial Ni-catalyst at ambient pressure and in a pressurized steel reactor (without catalyst) to examine coking during the thermal decomposition of Hc. The catalytic experiments at atmospheric pressure showed that a recycle of CH{sub 4} did not cause coking up to a ratio of CH{sub 4}/CO{sub 2} below one. For these conditions, long term stability was proved. The reaction rates of the CH{sub 4} conversion were below those of the RWGS reaction. However, replacing CH{sub 4} by C{sub 3}H{sub 8} leads to thermal and catalytic coking. Catalytic coking hits the maximum level at about 700 C and decreases for higher temperatures and, thus is not regarded as a problem for the RWGS reactor. In contrast to that, thermal coking raises with higher temperatures, but it can be supressed efficiently with additional injection of H{sub 2}O, which of course shifts the equilibrium towards the undesired reactant side. (orig.)
Process for treating hydrocarbons, etc

Energy Technology Data Exchange (ETDEWEB)

1933-09-15

A process is described for treating simultaneously bituminous substances and hydrocarbon oils for the production of low-boiling hydrocarbons and volatilization of the bituminous substances, characterized by the fact that it consists of heating a current of charge constituted by a mixture of the bituminous substances and hydrocarbon oils, to a high temperature, passing the heated current into a zone of extended reaction where the vapors are separated from the liquid or solid residue to favor transformation of the liquid hydrocarbons and volatilization of the bituminous substances, owing to the utilization of a heating agent carried to a high temperature being brought in contact with the heated charge in order to communicate its heat to the charge, while this later presents itself as relatively fine pellet or in the condition of distinct particles, particularly separated from one another.
Interactions between oxygen permeation and homogeneous-phase fuel conversion on the sweep side of an ion transport membrane

KAUST Repository

Hong, Jongsup

2013-02-01

The interactions between oxygen permeation and homogeneous fuel oxidation reactions on the sweep side of an ion transport membrane (ITM) are examined using a comprehensive model, which couples the dependency of the oxygen permeation rate on the membrane surface conditions and detailed chemistry and transport in the vicinity of the membrane. We assume that the membrane surface is not catalytic to hydrocarbon or syngas oxidation. Results show that increasing the sweep gas inlet temperature and fuel concentration enhances oxygen permeation substantially. This is accomplished through promoting oxidation reactions (oxygen consumption) and the transport of the products and reaction heat towards the membrane, which lowers the oxygen concentration and increases the gas temperature near the membrane. Faster reactions at higher fuel concentration and higher inlet gas temperature support substantial fuel conversion and lead to a higher oxygen permeation flux without the contribution of surface catalytic activity. Beyond a certain maximum in the fuel concentration, extensive heat loss to the membrane (and feed side) reduces the oxidation kinetic rates and limits oxygen permeation as the reaction front reaches the membrane. The sweep gas flow rate and channel height have moderate impacts on oxygen permeation and fuel conversion due to the residence time requirements for the chemical reactions and the location of the reaction zone relative to the membrane surface. © 2012 Elsevier B.V.
Chemical Kinetics of Hydrocarbon Ignition in Practical Combustion Systems

International Nuclear Information System (INIS)

Westbrook, C.K.

2000-01-01

Chemical kinetic factors of hydrocarbon oxidation are examined in a variety of ignition problems. Ignition is related to the presence of a dominant chain branching reaction mechanism that can drive a chemical system to completion in a very short period of time. Ignition in laboratory environments is studied for problems including shock tubes and rapid compression machines. Modeling of the laboratory systems are used to develop kinetic models that can be used to analyze ignition in practical systems. Two major chain branching regimes are identified, one consisting of high temperature ignition with a chain branching reaction mechanism based on the reaction between atomic hydrogen with molecular oxygen, and the second based on an intermediate temperature thermal decomposition of hydrogen peroxide. Kinetic models are then used to describe ignition in practical combustion environments, including detonations and pulse combustors for high temperature ignition, and engine knock and diesel ignition for intermediate temperature ignition. The final example of ignition in a practical environment is homogeneous charge, compression ignition (HCCI) which is shown to be a problem dominated by the kinetics intermediate temperature hydrocarbon ignition. Model results show why high hydrocarbon and CO emissions are inevitable in HCCI combustion. The conclusion of this study is that the kinetics of hydrocarbon ignition are actually quite simple, since only one or two elementary reactions are dominant. However, there are many combustion factors that can influence these two major reactions, and these are the features that vary from one practical system to another
A PROCESS FOR THE CATALYTIC OXIDATION OF HYDROCARBONS

DEFF Research Database (Denmark)

1999-01-01

A process for producing an alcohol from a gaseous hydrocarbon, e.g. a lower alkane such as methane, via oxidative reaction of the hydrocarbon in a concentrated sulfuric acid medium in the presence of a catalyst employs an added catalyst comprising a substance selected from iodine, iodine compounds...
Conversion of hydrocarbons and alcohols for fuel cells

Science.gov (United States)

Joensen, Finn; Rostrup-Nielsen, Jens R.

The growing demand for clean and efficient energy systems is the driving force in the development of fuel processing technology for providing hydrogen or hydrogen-containing gaseous fuels for power generation in fuel cells. Successful development of low cost, efficient fuel processing systems will be critical to the commercialisation of this technology. This article reviews various reforming technologies available for the generation of such fuels from hydrocarbons and alcohols. It also briefly addresses the issue of carbon monoxide clean-up and the question of selecting the appropriate fuel(s) for small/medium scale fuel processors for stationary and automotive applications.
Effects of operating conditions on compositional characteristics and reaction kinetics of liquid derived by delayed coking of nigerian petroleum residue

Directory of Open Access Journals (Sweden)

O. O. Bello

2006-09-01

Full Text Available The thermal upgrading of Nigerian petroleum residue was studied at relatively low pressure in a delayed coking reactor system. In this work, the intent was to investigate the effects of process variables such as reaction temperature (200(0C to 600(0C, reaction time (0 to 120min, additive concentration loading and additive-to-residue ratio on the amounts and quality of organic liquid product (OLP. The liquid products derived from the delayed coking process were characterized by means of instrumental analysis of gas-liquid chromatography. Results obtained from the analyses of the OLP revealed an upward trend of the conversion process and the selectivity of the aromatic compounds with additive-to-residue ratio (ARR and increase in temperature. This led to maximum yield of 37.2% achieved with ARR of 5 compared to 31% achieved with ordinary thermal conversion. The selectivity for aromatic hydrocarbons was maximum at 83.1wt% the selectivity towards aromatics and aliphatic hydrocarbons were highest for methanol-potassium hydroxide and methanol respectively. In all additive system cases, maximum OLP was produced at an optimum reaction temperature of 370(0C in the delayed coking reactor and at higher residence time. The gaseous product consisted of carbon monoxide and carbon dioxide and C1 - C6 hydrocarbons, which amounted to about 20 to 30 wt% of liquid distillate. The information obtained in this study show that the organic liquid products are amenable to characterization procedure and provided the basis for the identification of processes for upgrading Nigerian petroleum residue and such other starting materials such as bitumen or fossil fuel coal liquids.

Crossed-beam reaction of carbon atoms with hydrocarbon molecules. IV. Chemical dynamics of methylpropargyl radical formation, C4H5, from reaction of C(3Pj) with propylene, C3H6 (X1A)

International Nuclear Information System (INIS)

Kaiser, R.I.; Stranges, D.; Bevsek, H.M.; Lee, Y.T.; Suits, A.G.

1997-01-01

The reaction between ground state carbon atoms and propylene, C 3 H 6 , was studied at average collision energies of 23.3 and 45.0 kJmol -1 using the crossed molecular beam technique. Product angular distributions and time-of-flight spectra of C 4 H 5 at m/e=53 were recorded. Forward-convolution fitting of the data yields a maximum energy release as well as angular distributions consistent with the formation of methylpropargyl radicals. Reaction dynamics inferred from the experimental results suggest that the reaction proceeds on the lowest 3 A surface via an initial addition of the carbon atom to the π-orbital to form a triplet methylcyclopropylidene collision complex followed by ring opening to triplet 1,2-butadiene. Within 0.3 endash 0.6 ps, 1,2-butadiene decomposes through carbon endash hydrogen bond rupture to atomic hydrogen and methylpropargyl radicals. The explicit identification of C 4 H 5 under single collision conditions represents a further example of a carbon endash hydrogen exchange in reactions of ground state carbon with unsaturated hydrocarbons. This versatile machine represents an alternative pathway to build up unsaturated hydrocarbon chains in combustion processes, chemical vapor deposition, and in the interstellar medium. copyright 1997 American Institute of Physics
Experimental comparison among hydrocarbon and oxygenated compounds for their elimination by three-way automotive catalysts

International Nuclear Information System (INIS)

Bart, J.M.; Prigent, M.F.

1992-01-01

Many hydrocarbon species are present in automotive exhaust gases, and three-way Pt-Rh catalysts are commonly used for their elimination. However, most published work on individual hydrocarbon conversion concerns their oxidation in simulated exhaust gases with excess oxygen. This paper reports that this study was therefore undertaken to determine the reactivity of saturated alkanes, olefins, acetylene, aromatics, alcohols or various other oxygenated compounds in steady state conditions with synthetic exhaust gases near stoichiometry. In a first series of measurements, conversion rates were determined as a function of temperature at stoichiometry. The partial pressure effect of O 2 , NO and H 2 O was then determined at constant temperature in the region of catalyst light-off. NO and mainly O 2 were shown to have a negative effect on the first terms of saturated alkane conversion under lean conditions. Water vapor has a positive effect in rich conditions (without SO 2 ), but is more pronounced for Pt-Rh than for a Pt catalyst. Finally, the role played by SO 2 in hydrocarbon conversion was evaluated
Estimating fair-market value for hydrocarbon producing properties

International Nuclear Information System (INIS)

Garb, F.A.

1996-01-01

The generally accepted appraisal methods used to evaluate hydrocarbon properties and prospects were described. Fair-market-value (FMV) estimates have been used in the petroleum industry in attempts to protect a purchaser against an unwise acquisition, or conversely, to establish a just price to compensate a seller. Four methods were identified for determining FMV for hydrocarbon producing properties. They are: (1) comparative sales, (2) rule of thumb, (3) income forecast, and (4) replacement cost. The differences between oil and gas FMV and real estate FMV were explained
Natural gas conversion. Part VI

International Nuclear Information System (INIS)

Iglesia, E.; Spivey, J.J.; Fleisch, T.H.

2001-01-01

This volume contains peer-reviewed manuscripts describing the scientific and technological advances presented at the 6th Natural Gas Conversion Symposium held in Alaska in June 2001. This symposium continues the tradition of excellence and the status as the premier technical meeting in this area established by previous meetings. The 6th Natural Gas Conversion Symposium is conducted under the overall direction of the Organizing Committee. The Program Committee was responsible for the review, selection, editing of most of the manuscripts included in this volume. A standing International Advisory Board has ensured the effective long-term planning and the continuity and technical excellence of these meetings. The titles of the contributions are: Impact of syngas generation technology selection on a GTL FPSO; Methane conversion via microwave plasma initiated by a metal initiator; Mechanism of carbon deposit/removal in methane dry reforming on supported metal catalysts; Catalyst-assisted oxidative dehydrogenation of light paraffins in short contact time reactors; Catalytic dehydrogenation of propane over a PtSn/SiO 2 catalyst with oxygen addition: selective oxidation of H2 in the presence of hydrocarbons; Hydroconversion of a mixture of long chain n-paraffins to middle distillate: effect of the operating parameters and products properties; Decomposition/reformation processes and CH4 combustion activity of PdO over Al2O3 supported catalysts for gas turbine applications; Lurgi's mega-methanol technology opens the door for a new era in down-stream applications;Expanding markets for GTL fuels and specialty products; Some critical issues in the analysis of partial oxidation reactions in monolith reactors
Nanoscale intimacy in bifunctional catalysts for selective conversion of hydrocarbons

Science.gov (United States)

Zecevic, Jovana; Vanbutsele, Gina; de Jong, Krijn P.; Martens, Johan A.

2015-12-01

The ability to control nanoscale features precisely is increasingly being exploited to develop and improve monofunctional catalysts. Striking effects might also be expected in the case of bifunctional catalysts, which are important in the hydrocracking of fossil and renewable hydrocarbon sources to provide high-quality diesel fuel. Such bifunctional hydrocracking catalysts contain metal sites and acid sites, and for more than 50 years the so-called intimacy criterion has dictated the maximum distance between the two types of site, beyond which catalytic activity decreases. A lack of synthesis and material-characterization methods with nanometre precision has long prevented in-depth exploration of the intimacy criterion, which has often been interpreted simply as ‘the closer the better’ for positioning metal and acid sites. Here we show for a bifunctional catalyst—comprising an intimate mixture of zeolite Y and alumina binder, and with platinum metal controllably deposited on either the zeolite or the binder—that closest proximity between metal and zeolite acid sites can be detrimental. Specifically, the selectivity when cracking large hydrocarbon feedstock molecules for high-quality diesel production is optimized with the catalyst that contains platinum on the binder, that is, with a nanoscale rather than closest intimacy of the metal and acid sites. Thus, cracking of the large and complex hydrocarbon molecules that are typically derived from alternative sources, such as gas-to-liquid technology, vegetable oil or algal oil, should benefit especially from bifunctional catalysts that avoid locating platinum on the zeolite (the traditionally assumed optimal location). More generally, we anticipate that the ability demonstrated here to spatially organize different active sites at the nanoscale will benefit the further development and optimization of the emerging generation of multifunctional catalysts.
Inertial confinement fusion reaction chamber and power conversion system study. Final report

International Nuclear Information System (INIS)

Maya, I.; Schultz, K.R.; Bourque, R.F.

1985-10-01

This report summarizes the results of the second year of a two-year study on the design and evaluation of the Cascade concept as a commercial inertial confinement fusion (ICF) reactor. We developed a reactor design based on the Cascade reaction chamber concept that would be competitive in terms of both capital and operating costs, safe and environmentally acceptable in terms of hazard to the public, occupational exposure and radioactive waste production, and highly efficient. The Cascade reaction chamber is a double-cone-shaped rotating drum. The granulated solid blanket materials inside the rotating chamber are held against the walls by centrifugal force. The fusion energy is captured in a blanket of solid carbon, BeO, and LiAlO 2 granules. These granules are circulated to the primary side of a ceramic heat exchanger. Primary-side granule temperatures range from 1285 K at the LiAlO 2 granule heat exchanger outlet to 1600 K at the carbon granule heat exchanger inlet. The secondary side consists of a closed-cycle gas turbine power conversion system with helium working fluid, operating at 1300 K peak outlet temperature and achieving a thermal power conversion efficiency of 55%. The net plant efficiency is 49%. The reference design is a plant producing 1500 MW of D-T fusion power and delivering 815 MW of electrical power for sale to the utility grid. 88 refs., 44 figs., 47 tabs
Microbial consortia involved in the anaerobic degradation of hydrocarbons.

Science.gov (United States)

Zwolinski; Harris, R F; Hickey, W J

2000-01-01

In this review, we examine the energetics of well-characterized biodegradation pathways and explore the possibilities for these to support growth of multiple organisms interacting in consortia. The relevant phenotypic and/or phylogenetic characteristics of isolates and consortia mediating hydrocarbon degradation coupled with different terminal electron-accepting processes (TEAP) are also reviewed. While the information on metabolic pathways has been gained from the analysis of individual isolates, the energetic framework presented here demonstrates that microbial consortia could be readily postulated for hydrocarbon degradation coupled to any TEAP. Several specialized reactions occur within these pathways, and the organisms mediating these are likely to play a key role in defining the hydrocarbon degradation characteristics of the community under a given TEAP. Comparing these processes within and between TEAPs reveals biological unity in that divergent phylotypes display similar degradation mechanisms and biological diversity in that hydrocarbon-degraders closely related as phylotypes differ in the type and variety of hydrocarbon degradation pathways they possess. Analysis of microcosms and of field samples suggests that we have only begun to reveal the diversity of organisms mediating anaerobic hydrocarbon degradation. Advancements in the understanding of how hydrocarbon-degrading communities function will be significantly affected by the extent to which organisms mediating specialized reactions can be identified, and tools developed to allow their study in situ.
Reactions and reaction intermediates on iron surfaces--1. Methanol, ethanol, and isopropanol on Fe(100). 2. Hydrocarbons and carboxylic acids

Energy Technology Data Exchange (ETDEWEB)

Benziger, J.B.; Madix, R.J.

1980-09-01

Temperature-programed desorption and ESCA showed that the alcohols formed alkoxy intermediates on Fe(100) surfaces at room temperature, but that the methoxy and ethoxy species were much more stable than the isopropoxy intermediate. The alkoxy species reacted above 400/sup 0/K by decomposing into carbon monoxide and hydrogen, hydrogenation to alcohol, and scission of C-C and C-O bonds with hydrogenation of the hydrocarbon fragments. Ethylene, acetylene, and cis-2-butene formed stable, unidentified surface species. Methyl chloride formed stable surface methyl groups which decomposed into hydrogen and surface carbide at 475/sup 0/K. Formic and acetic acids yielded stable carboxylate intermediates which decomposed above 490/sup 0/K to hydrogen, carbon monoxide, and carbon dioxide. The studies suggested that the alkoxy surface species may be important intermediates in the Fischer-Tropsch reaction on iron.
Neutralization of methyl cation via chemical reactions in low-energy ion-surface collisions with fluorocarbon and hydrocarbon self-assembled monolayer films.

Science.gov (United States)

Somogyi, Arpád; Smith, Darrin L; Wysocki, Vicki H; Colorado, Ramon; Lee, T Randall

2002-10-01

Low-energy ion-surface collisions of methyl cation at hydrocarbon and fluorocarbon self-assembled monolayer (SAM) surfaces produce extensive neutralization of CH3+. These experimental observations are reported together with the results obtained for ion-surface collisions with the molecular ions of benzene, styrene, 3-fluorobenzonitrile, 1,3,5-triazine, and ammonia on the same surfaces. For comparison, low-energy gas-phase collisions of CD3+ and 3-fluorobenzonitrile molecular ions with neutral n-butane reagent gas were conducted in a triple quadrupole (QQQ) instrument. Relevant MP2 6-31G*//MP2 6-31G* ab initio and thermochemical calculations provide further insight in the neutralization mechanisms of methyl cation. The data suggest that neutralization of methyl cation with hydrocarbon and fluorocarbon SAMs occurs by concerted chemical reactions, i.e., that neutralization of the projectile occurs not only by a direct electron transfer from the surface but also by formation of a neutral molecule. The calculations indicate that the following products can be formed by exothermic processes and without appreciable activation energy: CH4 (formal hydride ion addition) and C2H6 (formal methyl anion addition) from a hydrocarbon surface and CH3F (formal fluoride addition) from a fluorocarbon surface. The results also demonstrate that, in some cases, simple thermochemical calculations cannot be used to predict the energy profiles because relatively large activation energies can be associated with exothermic reactions, as was found for the formation of CH3CF3 (formal addition of trifluoromethyl anion).
Hydrocarbon-soluble calcium hydride: a "worker-bee" in calcium chemistry.

Science.gov (United States)

Spielmann, Jan; Harder, Sjoerd

2007-01-01

The reactivity of the hydrocarbon-soluble calcium hydride complex [{CaH(dipp-nacnac)(thf)}(2)] (1; dipp-nacnac=CH{(CMe)(2,6-iPr(2)C(6)H(3)N)}(2)) with a large variety of substrates has been investigated. Addition of 1 to C=O and C=N functionalities gave easy access to calcium alkoxide and amide complexes. Similarly, reduction of the C[triple chemical bond]N bond in a cyanide or an isocyanide resulted in the first calcium aldimide complexes [Ca{N=C(H)R}(dipp-nacnac)] and [Ca{C(H)=NR}(dipp-nacnac)], respectively. Complexation of 1 with borane or alane Lewis acids gave the borates and alanates as contact ion pairs. In reaction with epoxides, nucleophilic ring-opening is observed as the major reaction. The high reactivity of hydrocarbon-soluble 1 with most functional groups contrasts strongly with that of insoluble CaH(2), which is essentially inert and is used as a common drying agent. Crystal structures of the following products are presented: [{Ca{OC(H)Ph(2)}(dipp-nacnac)}(2)], [{Ca{N=C(H)Ph}(dipp-nacnac)}(2)], [{Ca{C(H)=NC(Me)(2)CH(2)C(Me)(3)}(dipp-nacnac)}(2)], [{Ca{C(H)=NCy}(dipp-nacnac)}(2)], [Ca(dipp-nacnac)(thf)](+)[H(2)BC(8)H(14)](-) and [{Ca(OCy)(dipp-nacnac)}(2)]. The generally smooth and clean conversions of 1 with a variety of substrates and the stability of most intermediates against ligand exchange make 1 a valuable key precursor in the syntheses of a wide variety of beta-diketiminate calcium complexes.
A mechanistic basis for the effect of aluminum content on ethene selectivity in methanol-to-hydrocarbons conversion on HZSM-5

KAUST Repository

Khare, Rachit; Liu, Zhaohui; Han, Yu; Bhan, Aditya

2017-01-01

Increasing crystallize size or aluminum content in MFI-type zeolites independently enhances the propagation of the aromatics-based methylation/dealkylation cycle relative to that of the olefins-based methylation/cracking cycle in methanol-to-hydrocarbons (MTH) conversion and consequentially results in higher ethene selectivity. Ethene selectivity increases monotonically with increasing aluminum content for HZSM-5 samples with nearly identical crystallite size consequent to an increase in the intracrystalline contact time analogous to our recent report detailing the effects of crystallite size (Khare et al., 2015) on MTH selectivity. The confected effects of crystallite size and site density on MTH selectivity can therefore, be correlated using a descriptor that represents the average number of acid sites that an olefin-precursor will interact with before elution.
A mechanistic basis for the effect of aluminum content on ethene selectivity in methanol-to-hydrocarbons conversion on HZSM-5

KAUST Repository

Khare, Rachit

2017-03-20

Increasing crystallize size or aluminum content in MFI-type zeolites independently enhances the propagation of the aromatics-based methylation/dealkylation cycle relative to that of the olefins-based methylation/cracking cycle in methanol-to-hydrocarbons (MTH) conversion and consequentially results in higher ethene selectivity. Ethene selectivity increases monotonically with increasing aluminum content for HZSM-5 samples with nearly identical crystallite size consequent to an increase in the intracrystalline contact time analogous to our recent report detailing the effects of crystallite size (Khare et al., 2015) on MTH selectivity. The confected effects of crystallite size and site density on MTH selectivity can therefore, be correlated using a descriptor that represents the average number of acid sites that an olefin-precursor will interact with before elution.
Imaging fluid/solid interactions in hydrocarbon reservoir rocks.

Science.gov (United States)

Uwins, P J; Baker, J C; Mackinnon, I D

1993-08-01

The environmental scanning electron microscope (ESEM) has been used to image liquid hydrocarbons in sandstones and oil shales. Additionally, the fluid sensitivity of selected clay minerals in hydrocarbon reservoirs was assessed via three case studies: HCl acid sensitivity of authigenic chlorite in sandstone reservoirs, freshwater sensitivity of authigenic illite/smectite in sandstone reservoirs, and bleach sensitivity of a volcanic reservoir containing abundant secondary chlorite/corrensite. The results showed the suitability of using ESEM for imaging liquid hydrocarbon films in hydrocarbon reservoirs and the importance of simulating in situ fluid-rock interactions for hydrocarbon production programmes. In each case, results of the ESEM studies greatly enhanced prediction of reservoir/borehole reactions and, in some cases, contradicted conventional wisdom regarding the outcome of potential engineering solutions.
Recovering hydrocarbons with surfactants from lignin

Energy Technology Data Exchange (ETDEWEB)

Naae, D.G.; Whittington, L.E.; Ledoux, W.A.; Debons, F.E.

1988-11-29

This patent describes a method of recovering hydrocarbons from an underground hydrocarbon formation penetrated by at least one injection well and at least one production well, which comprises: injecting into the formation through an injection well a surfactant slug comprising about 0.1% to about 10% by weight of surfactants produced from lignin, the surfactants produced by placing lignin in contact with water, converting the lignin into low molecular weight lignin phenols by reducing the lignin in the presence of a reducing agent of carbon monoxide or hydrogen creating a reduction reaction mixture comprising oil soluble lignin phenols, the reduction occurring at a temperature greater than about 200/sup 0/C and a pressure greater than about 100 psi, recovering the oil soluble lignin phenols from the reduction mixture, and converting the lignin phenols into lignin surfactants by a reaction selected from the group consisting of alkoxylation, sulfonation, sulfation, aklylation, sulfomethylation, and alkoxysulfation; injecting into the formation through the injection well a drive fluid to push the surfactant slug towards a production well; and recovering hydrocarbons at the production well.
Feedstock Supply System Design and Economics for Conversion of Lignocellulosic Biomass to Hydrocarbon Fuels: Conversion Pathway: Biological Conversion of Sugars to Hydrocarbons The 2017 Design Case

Energy Technology Data Exchange (ETDEWEB)

Kevin Kenney; Kara G. Cafferty; Jacob J. Jacobson; Ian J Bonner; Garold L. Gresham; William A. Smith; David N. Thompson; Vicki S. Thompson; Jaya Shankar Tumuluru; Neal Yancey

2013-09-01

The U.S. Department of Energy promotes the production of a range of liquid fuels and fuel blendstocks from lignocellulosic biomass feedstocks by funding fundamental and applied research that advances the state of technology in biomass collection, conversion, and sustainability. As part of its involvement in this program, the Idaho National Laboratory (INL) investigates the feedstock logistics economics and sustainability of these fuels. Between 2000 and 2012, INL conducted a campaign to quantify the economics and sustainability of moving biomass from standing in the field or stand to the throat of the biomass conversion process. The goal of this program was to establish the current costs based on conventional equipment and processes, design improvements to the current system, and to mark annual improvements based on higher efficiencies or better designs. The 2012 programmatic target was to demonstrate a delivered biomass logistics cost of $35/dry ton. This goal was successfully achieved in 2012 by implementing field and process demonstration unit-scale data from harvest, collection, storage, preprocessing, handling, and transportation operations into INL’s biomass logistics model. Looking forward to 2017, the programmatic target is to supply biomass to the conversion facilities at a total cost of $80/dry ton and on specification with in-feed requirements. The goal of the 2017 Design Case is to enable expansion of biofuels production beyond highly productive resource areas by breaking the reliance of cost-competitive biofuel production on a single, abundant, low-cost feedstock. If this goal is not achieved, biofuel plants are destined to be small and/or clustered in select regions of the country that have a lock on low-cost feedstock. To put the 2017 cost target into perspective of past accomplishments of the cellulosic ethanol pathway, the $80 target encompasses total delivered feedstock cost, including both grower payment and logistics costs, while meeting all
Two-stage Catalytic Reduction of NOx with Hydrocarbons

Energy Technology Data Exchange (ETDEWEB)

Umit S. Ozkan; Erik M. Holmgreen; Matthew M. Yung; Jonathan Halter; Joel Hiltner

2005-12-21

A two-stage system for the catalytic reduction of NO from lean-burn natural gas reciprocating engine exhaust is investigated. Each of the two stages uses a distinct catalyst. The first stage is oxidation of NO to NO{sub 2} and the second stage is reduction of NO{sub 2} to N{sub 2} with a hydrocarbon. The central idea is that since NO{sub 2} is a more easily reduced species than NO, it should be better able to compete with oxygen for the combustion reaction of hydrocarbon, which is a challenge in lean conditions. Early work focused on demonstrating that the N{sub 2} yield obtained when NO{sub 2} was reduced was greater than when NO was reduced. NO{sub 2} reduction catalysts were designed and silver supported on alumina (Ag/Al{sub 2}O{sub 3}) was found to be quite active, able to achieve 95% N{sub 2} yield in 10% O{sub 2} using propane as the reducing agent. The design of a catalyst for NO oxidation was also investigated, and a Co/TiO{sub 2} catalyst prepared by sol-gel was shown to have high activity for the reaction, able to reach equilibrium conversion of 80% at 300 C at GHSV of 50,000h{sup -1}. After it was shown that NO{sub 2} could be more easily reduced to N{sub 2} than NO, the focus shifted on developing a catalyst that could use methane as the reducing agent. The Ag/Al{sub 2}O{sub 3} catalyst was tested and found to be inactive for NOx reduction with methane. Through iterative catalyst design, a palladium-based catalyst on a sulfated-zirconia support (Pd/SZ) was synthesized and shown to be able to selectively reduce NO{sub 2} in lean conditions using methane. Development of catalysts for the oxidation reaction also continued and higher activity, as well as stability in 10% water, was observed on a Co/ZrO{sub 2} catalyst, which reached equilibrium conversion of 94% at 250 C at the same GHSV. The Co/ZrO{sub 2} catalyst was also found to be extremely active for oxidation of CO, ethane, and propane, which could potential eliminate the need for any separate
Catalytic cracking of hydrocarbon oils

Energy Technology Data Exchange (ETDEWEB)

1940-09-12

A process is described for the vapor phase catalytic cracking of hydrocarbon oils boiling substantially in the gas oil range. The reaction takes place in the presence of a solid catalyst between 700 to 900/sup 0/F under pressure between atmospheric and 400 psi. A gas containing between 20 and 90 mol % of free hydrogen is used. The reaction is allowed to proceed until consumption of the free begins. The reaction is discontinued at that point and the catalyst is regenerated for further use.
Heterogeneous OH oxidation of motor oil particles causes selective depletion of branched and less cyclic hydrocarbons.

Science.gov (United States)

Isaacman, Gabriel; Chan, Arthur W H; Nah, Theodora; Worton, David R; Ruehl, Chris R; Wilson, Kevin R; Goldstein, Allen H

2012-10-02

Motor oil serves as a useful model system for atmospheric oxidation of hydrocarbon mixtures typical of anthropogenic atmospheric particulate matter, but its complexity often prevents comprehensive chemical speciation. In this work we fully characterize this formerly "unresolved complex mixture" at the molecular level using recently developed soft ionization gas chromatography techniques. Nucleated motor oil particles are oxidized in a flow tube reactor to investigate the relative reaction rates of observed hydrocarbon classes: alkanes, cycloalkanes, bicycloalkanes, tricycloalkanes, and steranes. Oxidation of hydrocarbons in a complex aerosol is found to be efficient, with approximately three-quarters (0.72 ± 0.06) of OH collisions yielding a reaction. Reaction rates of individual hydrocarbons are structurally dependent: compared to normal alkanes, reaction rates increased by 20-50% with branching, while rates decreased ∼20% per nonaromatic ring present. These differences in rates are expected to alter particle composition as a function of oxidation, with depletion of branched and enrichment of cyclic hydrocarbons. Due to this expected shift toward ring-opening reactions heterogeneous oxidation of the unreacted hydrocarbon mixture is less likely to proceed through fragmentation pathways in more oxidized particles. Based on the observed oxidation-induced changes in composition, isomer-resolved analysis has potential utility for determining the photochemical age of atmospheric particulate matter with respect to heterogeneous oxidation.
Catalytic-Dielectric Barrier Discharge Plasma Reactor For Methane and Carbon Dioxide Conversion

Directory of Open Access Journals (Sweden)

Istadi Istadi

2007-10-01

Full Text Available A catalytic - DBD plasma reactor was designed and developed for co-generation of synthesis gas and C2+ hydrocarbons from methane. A hybrid Artificial Neural Network - Genetic Algorithm (ANN-GA was developed to model, simulate and optimize the reactor. Effects of CH4/CO2 feed ratio, total feed flow rate, discharge voltage and reactor wall temperature on the performance of catalytic DBD plasma reactor was explored. The Pareto optimal solutions and corresponding optimal operating parameters ranges based on multi-objectives can be suggested for catalytic DBD plasma reactor owing to two cases, i.e. simultaneous maximization of CH4 conversion and C2+ selectivity, and H2 selectivity and H2/CO ratio. It can be concluded that the hybrid catalytic DBD plasma reactor is potential for co-generation of synthesis gas and higher hydrocarbons from methane and carbon dioxide and showed better than the conventional fixed bed reactor with respect to CH4 conversion, C2+ yield and H2 selectivity for CO2 OCM process. © 2007 BCREC UNDIP. All rights reserved.[Presented at Symposium and Congress of MKICS 2007, 18-19 April 2007, Semarang, Indonesia][How to Cite: I. Istadi, N.A.S. Amin. (2007. Catalytic-Dielectric Barrier Discharge Plasma Reactor For Methane and Carbon Dioxide Conversion. Bulletin of Chemical Reaction Engineering and Catalysis, 2 (2-3: 37-44. doi:10.9767/bcrec.2.2-3.8.37-44][How to Link/DOI: http://dx.doi.org/10.9767/bcrec.2.2-3.8.37-44 || or local: http://ejournal.undip.ac.id/index.php/bcrec/article/view/8][Cited by: Scopus 1 |
Mechanistic studies on the OH-initiated atmospheric oxidation of selected aromatic hydrocarbons

Energy Technology Data Exchange (ETDEWEB)

Nehr, Sascha

2012-07-01

Benzene, toluene, the xylenes, and the trimethylbenzenes are among the most abundant aromatic trace constituents of the atmosphere mainly originating from anthropogenic sources. The OH-initiated atmospheric photo-oxidation of aromatic hydrocarbons is the predominant removal process resulting in the formation of O{sub 3} and secondary organic aerosol. Therefore, aromatics are important trace constituents regarding air pollution in urban environments. Our understanding of aromatic photo-oxidation processes is far from being complete. This work presents novel approaches for the investigation of OH-initiated atmospheric degradation mechanisms of aromatic hydrocarbons. Firstly, pulsed kinetic studies were performed to investigate the prompt HO{sub 2} formation from OH+ aromatic hydrocarbon reactions under ambient conditions. For these studies, the existing OH reactivity instrument, based on the flash photolysis/laser-induced fluorescence (FP/LIF) technique, was extended to the detection of HO{sub 2} radicals. The experimental design allows for the determination of HO{sub 2} formation yields and kinetics. Results of the pulsed kinetic experiments complement previous product studies and help to reduce uncertainties regarding the primary oxidation steps. Secondly, experiments with aromatic hydrocarbons were performed under atmospheric conditions in the outdoor atmosphere simulation chamber SAPHIR (Simulation of Atmospheric PHotochemistry In a large Reaction chamber) located at Forschungszentrum Juelich. The experiments were aimed at the evaluation of up-to-date aromatic degradation schemes of the Master Chemical Mechanism (MCMv3.2). The unique combination of analytical instruments operated at SAPHIR allows for a detailed investigation of HO{sub x} and NO{sub x} budgets and for the determination of primary phenolic oxidation product yields. MCMv3.2 deficiencies were identified and most likely originate from shortcomings in the mechanistic representation of ring

A Hierarchically Micro-Meso-Macroporous Zeolite CaA for Methanol Conversion to Dimethyl Ether

Directory of Open Access Journals (Sweden)

Yan Wang

2016-11-01

Full Text Available A hierarchical zeolite CaA with microporous, mesoporous and macroporous structure was hydrothermally synthesized by a ”Bond-Blocking” method using organo-functionalized mesoporous silica (MS as a silica source. The characterization by XRD, SEM/TEM and N2 adsorption/desorption techniques showed that the prepared material had well-crystalline zeolite Linde Type A (LTA topological structure, microspherical particle morphologies, and hierarchically intracrystalline micro-meso-macropores structure. With the Bond-Blocking principle, the external surface area and macro-mesoporosity of the hierarchical zeolite CaA can be adjusted by varying the organo-functionalized degree of the mesoporous silica surface. Similarly, the distribution of the micro-meso-macroporous structure in the zeolite CaA can be controlled purposely. Compared with the conventional microporous zeolite CaA, the hierarchical zeolite CaA as a catalyst in the conversion of methanol to dimethyl ether (DME, exhibited complete DME selectivity and stable catalytic activity with high methanol conversion. The catalytic performances of the hierarchical zeolite CaA results clearly from the micro-meso-macroporous structure, improving diffusion properties, favoring the access to the active surface and avoiding secondary reactions (no hydrocarbon products were detected after 3 h of reaction.
Final technical report for the Center for Catalytic Hydrocarbon Functionalization (an EFRC)

Energy Technology Data Exchange (ETDEWEB)

Gunnoe, Thomas Brent [Univ. of Virginia, Charlottesville, VA (United States)

2016-11-11

Greater than 95% of all materials produced by the chemical industry are derived from a small slate of simple hydrocarbons that are derived primarily from natural gas and petroleum, predominantly through oxygenation, C–C bond formation, halogenation or amination. Yet, current technologies for hydrocarbon conversion are typically high temperature, multi-step processes that are energy and capital intensive and result in excessive emissions (including carbon dioxide). The Center for Catalytic Hydrocarbon Functionalization (CCHF) brought together research teams with the broad coalition of skills and knowledge needed to make the fundamental advances in catalysis required for next-generation technologies to convert hydrocarbons (particularly light alkanes and methane) at high efficiency and low cost. Our new catalyst technologies offer many opportunities including enhanced utilization of natural gas in the transportation sector (via conversion to liquid fuels), more efficient generation of electricity from natural gas using direct methane fuel cells, reduced energy consumption and waste production for large petrochemical processes, and the preparation of high value molecules for use in biological/medical applications or the agricultural sector. The five year collaborative project accelerated fundamental understanding of catalyst design for the conversion of C–H bonds to functionalized products, essential to achieve the goals listed above, as evidenced by the publication of 134 manuscripts. Many of these fundamental advancements provide a foundation for potential commercialization, as evidenced by the submission of 11 patents from research support by the CCHF.
Structured catalyst bed and method for conversion of feed materials to chemical products and liquid fuels

Science.gov (United States)

Wang, Yong , Liu; Wei, [Richland, WA

2012-01-24

The present invention is a structured monolith reactor and method that provides for controlled Fischer-Tropsch (FT) synthesis. The invention controls mass transport limitations leading to higher CO conversion and lower methane selectivity. Over 95 wt % of the total product liquid hydrocarbons obtained from the monolithic catalyst are in the carbon range of C.sub.5-C.sub.18. The reactor controls readsorption of olefins leading to desired products with a preselected chain length distribution and enhanced overall reaction rate. And, liquid product analysis shows readsorption of olefins is reduced, achieving a narrower FT product distribution.
Algal Lipid Extraction and Upgrading to Hydrocarbons Technology Pathway

Energy Technology Data Exchange (ETDEWEB)

Davis, Ryan; Biddy, Mary J.; Jones, Susanne B.

2013-03-31

In support of the Bioenergy Technologies Office, the National Renewable Energy Laboratory (NREL) and the Pacific Northwest National Laboratory (PNNL) are undertaking studies of biomass conversion technologies to identify barriers and target research toward reducing conversion costs. Process designs and preliminary economic estimates for each of these pathway cases were developed using rigorous modeling tools (Aspen Plus and Chemcad). These analyses incorporated the best information available at the time of development, including data from recent pilot and bench-scale demonstrations, collaborative industrial and academic partners, and published literature and patents. This technology pathway case investigates the cultivation of algal biomass followed by further lipid extraction and upgrading to hydrocarbon biofuels. Technical barriers and key research needs have been assessed in order for the algal lipid extraction and upgrading pathway to be competitive with petroleum-derived gasoline, diesel and jet range hydrocarbon blendstocks.
Liquid-assisted grinding and ion pairing regulates percentage conversion and diastereoselectivity of the Wittig reaction under mechanochemical conditions.

Science.gov (United States)

Denlinger, Kendra Leahy; Ortiz-Trankina, Lianna; Carr, Preston; Benson, Kingsley; Waddell, Daniel C; Mack, James

2018-01-01

Mechanochemistry is maturing as a discipline and continuing to grow, so it is important to continue understanding the rules governing the system. In a mechanochemical reaction, the reactants are added into a vessel along with one or more grinding balls and the vessel is shaken at high speeds to facilitate a chemical reaction. The dielectric constant of the solvent used in liquid-assisted grinding (LAG) and properly chosen counter-ion pairing increases the percentage conversion of stilbenes in a mechanochemical Wittig reaction. Utilizing stepwise addition/evaporation of ethanol in liquid-assisted grinding also allows for the tuning of the diastereoselectivity in the Wittig reaction.
Conversion of methane to methanol in an ac dielectric barrier discharge

International Nuclear Information System (INIS)

Aghamir, F M; Matin, N S; Jalili, A H; Esfarayeni, M H; Khodagholi, M A; Ahmadi, R

2004-01-01

A dielectric barrier discharge (DBD) has been used to investigate the conversion of methane to methanol and higher hydrocarbons in ac non-equilibrium plasmas. Experiments were carried out at atmospheric pressure and ambient temperature. A non-equilibrium plasma was generated in a DBD reactor by applying a high voltage to the reactor electrodes. Activation of methane molecules led to the production of C 2 hydrocarbons and methanol. The effect of the applied voltage, residence time and feed mixture such as helium and oxygen on the methane conversion and product selectivity was studied. Helium appears to have no effect on the conversion and selectivity at our applied voltages. The methane conversion increases significantly on introduction of oxygen in the feed stream. Inclusion of oxygen leads to the formation of methanol. Our results show that production of methanol is initiated around an applied voltage of 12 kV and the conversion of methane increases with increasing voltage and residence time, while the product selectivity is independent of the applied voltage
Cyclic Versus Linear Isomers Produced by Reaction of the Methylidyne Radical (CH) with Small Unsaturated Hydrocarbons

Energy Technology Data Exchange (ETDEWEB)

Goulay, Fabien; Trevitt, Adam J.; Meloni, Giovanni; Selby, Talitha M.; Osborn, David L.; Taatjes, Craig A.; Vereecken, Luc; Leone, Stephen R.

2008-12-05

The reactions of the methylidyne radical (CH) with ethylene, acetylene, allene, and methylacetylene are studied at room temperature using tunable vacuum ultraviolet (VUV) photoionization and time-resolved mass spectrometry. The CH radicals are prepared by 248 nm multiphoton photolysis of CHBr3 at 298 K and react with the selected hydrocarbon in a helium gas flow. Analysis of photoionization efficiency versus VUV photon wavelength permits isomer-specific detection of the reaction products and allows estimation of the reaction product branching ratios. The reactions proceed by either CH insertion or addition followed by H atom elimination from the intermediate adduct. In the CH + C2H4 reaction the C3H5 intermediate decays by H atom loss to yield 70(+-8)percent allene, 30(+-8)percent methylacetylene and less than 10percent cyclopropene, in agreement with previous RRKM results. In the CH + acetylene reaction, detection of mainly the cyclic C3H2 isomer is contrary to a previous RRKM calculation that predicted linear triplet propargylene to be 90percent of the total H-atom co-products. High-level CBS-APNO quantum calculations and RRKM calculation for the CH + C2H2 reaction presented in this manuscript predict a higher contribution of the cyclic C3H2 (27.0percent) versus triplet propargylene (63.5percent) than these earlier predictions. Extensive calculations on the C3H3 and C3H2D system combined with experimental isotope ratios for the CD + C2H2 reaction indicate that H-atom assisted isomerization in the present experiments is responsible for the discrepancy between the RRKM calculations and the experimental results. Cyclic isomers are also found to represent 30(+-6)percent of the detected products in the case of CH + methylacetylene, together with 33(+-6)percent 1,2,3-butatriene and 37(+-6)percent vinylacetylene. The CH + allene reaction gives 23(+-5)percent 1,2,3-butatriene and 77(+-5)percent vinylacetylene, whereas cyclic isomers are produced below the detection limit
One-step hydroprocessing of fatty acids into renewable aromatic hydrocarbons over Ni/HZSM-5: insights into the major reaction pathways.

Science.gov (United States)

Xing, Shiyou; Lv, Pengmei; Wang, Jiayan; Fu, Junying; Fan, Pei; Yang, Lingmei; Yang, Gaixiu; Yuan, Zhenhong; Chen, Yong

2017-01-25

For high caloricity and stability in bio-aviation fuels, a certain content of aromatic hydrocarbons (AHCs, 8-25 wt%) is crucial. Fatty acids, obtained from waste or inedible oils, are a renewable and economic feedstock for AHC production. Considerable amounts of AHCs, up to 64.61 wt%, were produced through the one-step hydroprocessing of fatty acids over Ni/HZSM-5 catalysts. Hydrogenation, hydrocracking, and aromatization constituted the principal AHC formation processes. At a lower temperature, fatty acids were first hydrosaturated and then hydrodeoxygenated at metal sites to form long-chain hydrocarbons. Alternatively, the unsaturated fatty acids could be directly deoxygenated at acid sites without first being saturated. The long-chain hydrocarbons were cracked into gases such as ethane, propane, and C 6 -C 8 olefins over the catalysts' Brønsted acid sites; these underwent Diels-Alder reactions on the catalysts' Lewis acid sites to form AHCs. C 6 -C 8 olefins were determined as critical intermediates for AHC formation. As the Ni content in the catalyst increased, the Brønsted-acid site density was reduced due to coverage by the metal nanoparticles. Good performance was achieved with a loading of 10 wt% Ni, where the Ni nanoparticles exhibited a polyhedral morphology which exposed more active sites for aromatization.
Chemical kinetic models for combustion of hydrocarbons and formation of nitric oxide

Science.gov (United States)

Jachimowski, C. J.; Wilson, C. H.

1980-01-01

The formation of nitrogen oxides NOx during combustion of methane, propane, and a jet fuel, JP-4, was investigated in a jet stirred combustor. The results of the experiments were interpreted using reaction models in which the nitric oxide (NO) forming reactions were coupled to the appropriate hydrocarbon combustion reaction mechanisms. Comparison between the experimental data and the model predictions reveals that the CH + N2 reaction process has a significant effect on NO formation especially in stoichiometric and fuel rich mixtures. Reaction models were assembled that predicted nitric oxide levels that were in reasonable agreement with the jet stirred combustor data and with data obtained from a high pressure (5.9 atm (0.6 MPa)), prevaporized, premixed, flame tube type combustor. The results also suggested that the behavior of hydrocarbon mixtures, like JP-4, may not be significantly different from that of pure hydrocarbons. Application of the propane combustion and nitric oxide formation model to the analysis of NOx emission data reported for various aircraft gas turbines showed the contribution of the various nitric oxide forming processes to the total NOx formed.
Hydrocarbons and energy from plants: Final report, 1984-1987

Energy Technology Data Exchange (ETDEWEB)

Calvin, M.; Otvos, J.; Taylor, S.E.; Nemethy, E.K.; Skrukrud, C.L.; Hawkins, D.R.; Lago, R.

1988-08-01

Plant hydrocarbon (isoprenoid) production was investigated as an alternative source to fossil fuels. Because of their high triterpenoid (hydrocarbon) content of 4--8%, Euphorbia lathyris plants were used as a model system for this study. The structure of the E. lathyris triterpenoids was determined, and triterpenoid biosynthesis studied to better understand the metabolic regulation of isoprenoid production. Triterpenoid biosynthesis occurs in two distinct tissue types in E. lathyris plants: in the latex of the laticifer cells; and in the mesophyll cells of the leaf and stem. The latex has been fractionated by centrifugation, and it has been determined that the later steps of isoprenoid biosynthesis, the conversion of mevalonic acid to the triterpenes, are compartmentized within a vacuole. Also identified was the conversion of hydroxymethyl glutaryl-CoA to mevalonic acid, catalyzed by the enzyme Hydroxymethyl glutaryl-CoA Reductase, as a key rate limiting step in isoprenoid biosynthesis. At least two isozymes of this enzyme, one in the latex and another in the leaf plastids, have been identified. Environmental stress has been applied to plants to study changes in carbon allocation. Salinity stress caused a large decrease in growth, smaller decreases in photosynthesis, resulting in a larger allocation of carbon to both hydrocarbon and sugar production. An increase in Hydroxymethyl glutaryl-CoA Reductase activity was also observed when isoprenoid production increased. Other species where also screened for the production of hydrogen rich products such as isoprenoids and glycerides, and their hydrocarbon composition was determined.
Fundamental mechanisms for conversion of volatiles in biomass and waste combustion. Final report

Energy Technology Data Exchange (ETDEWEB)

Glarborg, P.; Hindiyarti, L.; Marshall, P.; Livbjerg, H.; Dagaut, P.; Jensen, Anker; Frandsen, Flemming

2007-03-15

This project deals with the volatile oxidation chemistry in biomass and waste fired systems, emphasizing reactions important for pollutants emissions (NO{sub x}, SO{sub 2}, HCl, aerosols). The project aims to extend existing models and databases with a number of chemical subsystems that are presently not well understood, but are particularly important in connection with combustion of biomass and waste. The project is divided into 3 tasks. Task 1: Conversion of chlorine, sulfur and alkali gas phase components in combustion of biomass. Task 2: Formation mechanisms for NO{sub x} in the freeboard of grate combustion of biomass. Task 3: Oxidation mechanisms for oxygenated hydrocarbons in the volatiles from pyrolysis of biomass. (au)
Radioisotope tracer study of co-reactions of methanol with ethanol using 11C-labelled methanol over alumina and H-ZSM-5

International Nuclear Information System (INIS)

Sarkadi-Priboczki, E.; Kovacs, Z.; Kumar, N.; Salmi, T.; Murzin, D.Yu

2005-01-01

Complete text of publication follows. The transformation of methanol has been investigated over alumina and H-ZSM-5 in our previous experiments by 11 C-radioisotope tracing. The main product in methanol conversion over alumina was dimethyl ether due to Lewis acid sites while over H-ZSM-5 mostly hydrocarbons were formed due to both Lewis and Brrnsted acid sites. With increasing temperature first the ethanol was dehydrated to diethyl ether followed by ethene formation over alumina and H-ZSM-5. In this work, 11 C-labelled methanol as radioisotope tracer was added to non-radioactive methanol for investigation of co-reaction with non-radioactive ethanol over alumina and H- ZSM-5. The 11 C-methanol tracer was used to distinguish the methanol derivates and co-reaction derivates of methanol with ethanol against non-radioactive ethanol derivates. The yield of methyl ethyl ether as mixed ether and the influence of ethanol for the yields of C 1 -C 5 hydrocarbons were studied as a function of reaction temperature and contact time. The 11 C-methanol was formed by a radiochemical process from 11 CO 2 produced at cyclotron. The mixture of methanol and ethanol was added to 11 C-methanol and injected to the catalyst. The catalysis was carried out in a glass tube fixed-bed reactor after its pretreatment. The derivates were analyzed by radio-gas chromatography (gas chromatograph with thermal conductivity detector coupled on-line with a radioactivity detector). The comparative analysis of yields of radioactive and non-radioactive products as a function of reaction temperature gives information about the reaction pathways. Over alumina the yields of dimethyl ether and methyl ethyl ether (co-product) as radioactive and diethyl ether with ethene as non-radioactive main products were monitored as a function of reaction temperature and reaction time in the range of 513-593 K. Alongside ethanol derivates the ethene turns into main product in contrast with methyl ethyl ether and diethyl
Carbon dioxide/methanol conversion cycle based on cascade enzymatic reactions supported on superparamagnetic nanoparticles

Directory of Open Access Journals (Sweden)

CATERINA G.C. MARQUES NETTO

2017-10-01

Full Text Available ABSTRACT The conversion of carbon dioxide into important industrial feedstock is a subject of growing interest in modern society. A possible way to achieve this goal is by carrying out the CO2/methanol cascade reaction, allowing the recycle of CO2 using either chemical catalysts or enzymes. Efficient and selective reactions can be performed by enzymes; however, due to their low stability, immobilization protocols are required to improve their performance. The cascade reaction to reduce carbon dioxide into methanol has been explored by the authors, using, sequentially, alcohol dehydrogenase (ADH, formaldehyde dehydrogenase (FalDH, and formate dehydrogenase (FDH, powered by NAD+/NADH and glutamate dehydrogenase (GDH as the co-enzyme regenerating system. All the enzymes have been immobilized on functionalized magnetite nanoparticles, and their reactions investigated separately in order to establish the best performance conditions. Although the stepwise scheme led to only 2.3% yield of methanol per NADH; in a batch system under CO2 pressure, the combination of the four immobilized enzymes increased the methanol yield by 64 fold. The studies indicated a successful regeneration of NADH in situ, envisaging a real possibility of using immobilized enzymes to perform the cascade CO2-methanol reaction.
Process for scavenging hydrogen sulfide from hydrocarbon gases

International Nuclear Information System (INIS)

Fox, I.

1981-01-01

A process for scavenging hydrogen sulfide from hydrocarbon gases utilizes iron oxide particles of unique chemical and physical properties. These particles have large surface area, and are comprised substantially of amorphous Fe 2 O 3 containing a crystalline phase of Fe 2 O 3 , Fe 3 O 4 and combinations thereof. In scavenging hydrogen sulfide, the iron oxide particles are suspended in a liquid which enters into intimate mixing contact with hydrocarbon gases; the hydrogen sulfide is reacted at an exceptional rate and only acid-stable reaction products are formed. Thereafter, the sweetened hydrocarbon gases are collected
Kinetic modeling of ethane pyrolysis at high conversion.

Science.gov (United States)

Xu, Chen; Al Shoaibi, Ahmed Sultan; Wang, Chenguang; Carstensen, Hans-Heinrich; Dean, Anthony M

2011-09-29

The primary objective of this study is to develop an improved first-principle-based mechanism that describes the molecular weight growth kinetics observed during ethane pyrolysis. A proper characterization of the kinetics of ethane pyrolysis is a prerequisite for any analysis of hydrocarbon pyrolysis and oxidation. Flow reactor experiments were performed with ~50/50 ethane/nitrogen mixtures with temperatures ranging from 550 to 850 °C at an absolute pressure of ~0.8 atm and a residence time of ~5 s. These conditions result in ethane conversions ranging from virtually no reaction to ~90%. Comparisons of predictions using our original mechanism to these data yielded very satisfactory results in terms of the temperature dependence of ethane conversion and prediction of the major products ethylene and hydrogen. However, there were discrepancies in some of the minor species concentrations that are involved in the molecular weight growth kinetics. We performed a series of CBS-QB3 analyses for the C(3)H(7), C(4)H(7), and C(4)H(9) potential energy surfaces to better characterize the radical addition reactions that lead to molecular weight growth. We also extended a published C(6)H(9) PES to include addition of vinyl to butadiene. The results were then used to calculate pressure-dependent rate constants for the multiple reaction pathways of these addition reactions. Inclusion of the unadjusted rate constants resulting from these analyses in the mechanism significantly improved the description of several of the species involved in molecular weight growth kinetics. We compare the predictions of this improved model to those obtained with a consensus model recently published as well as to ethane steam cracking data. We find that a particularly important reaction is that of vinyl addition to butadiene. Another important observation is that several radical addition reactions are partially equilibrated. Not only does this mean that reliable thermodynamic parameters are essential
Activity and selectivity regulation of synthesis gas reaction over supported ruthenium catalysts

Energy Technology Data Exchange (ETDEWEB)

Fujimoto, K; Nobusawa, T; Fukushima, T; Tominaga, H

1985-01-01

The catalytic activities of supported ruthenium for synthesis-gas conversion to hydrocarbons was found to be in the following order: TiOS > Nb2O3 > ZrO2 > SiO2 > Ta2O5 > Al2O3 > V2O5 > MoO3 > WO3 > MnO2 > ZnO. Turnover frequencies of the supported ruthenium increased with decrease in dispersion of the metal particles for every carrier material. Even the activities per unit weight of metals were higher for low-dispersion ruthenium of Al2O3, TiO2, and ZrO2. The chain-growth probability of a hydrocarbon product, which is characterized by the Schulz-Flory distribution, increased markedly with decrease in the metal dispersion irrespective of the carrier material. The catalytic activity of ruthenium particles with a dispersed ruthenium increased almost linearly with an increase in reaction pressure (up to at least 2.0 MPa). 23 references, 10 figures, 3 tables.
Partial oxidation of jet fuels over Rh/Al_2O_3. Design and reaction kinetics of sulfur-containing surrogates

International Nuclear Information System (INIS)

Baer, Julian Nicolaas

2016-01-01

The conversion of logistic fuels via catalytic partial oxidation (CPOX) on Rh/Al_2O_3 at short contact times is an efficient method for generating hydrogen-rich synthesis gas. Depending on the inlet conditions, fuel, and catalyst, high syngas yields, low by-product formation, and rates of high fuel conversion can be achieved. CPOX is relevant for mobile hydrogen generation, e.g., on board of airplanes in order to increase the fuel efficiency via fuel cell-based auxiliary power units. Jet fuels contain hundreds of different hydrocarbons and a significant amount of sulfur. The hydrocarbon composition and sulfur content of a jet fuel vary depending on distributor, origin, and refinement of the crude oil. Little is known about the influence of the various compounds on the synthesis-gas yield and the impact of sulfur on the product yield. In this work, the influence of three main chemical compounds of a jet fuel (aromatics, alkanes, and sulfur compounds) on syngas selectivity, the catalyst deactivation process, and reaction sequence is unraveled. As representative components of alkanes and aromatics, n-dodecane and 1,2,4-trimethylbenzene were chosen for ex-situ and in-situ investigations on the CPOX over Rh/Al_2O_3, respectively. Additionally, for a fixed paraffin-to-aromatics ratio, benzothiophene or dibenzothiophene were added as a sulfur component in three different concentrations. The knowledge gained about the catalytic partial oxidation of jet fuels and their surrogates is used to identify requirements for jet fuels in mobile applications based on CPOX and to optimize the overall system efficiency. The results show an influence of the surrogate composition on syngas selectivity. The tendency for syngas formation increases with higher paraffin contents. A growing tendency for by-product formation can be observed with increasing aromatics contents in the fuel. The impact of sulfur on the reaction system shows an immediate change in the product distribution. An
Direct conversion of fusion energy

International Nuclear Information System (INIS)

Johansson, Markus

2003-03-01

Deuterium and tritium are expected to be used as fuel in the first fusion reactors. Energy is released as kinetic energy of ions and neutrons, when deuterium reacts with tritium. One way to convert the kinetic energy to electrical energy, is to let the ions and neutrons hit the reactor wall and convert the heat that is caused by the particle bombardment to electrical energy with ordinary thermal conversion. If the kinetic energy of the ions instead is converted directly to electrical energy, a higher efficiency of the energy conversion is possible. The majority of the fusion energy is released as kinetic energy of neutrons, when deuterium reacts with tritium. Fusion reactions such as the D-D reactions, the D- 3 He reaction and the p- 11 B reaction, where a larger part of the fusion energy becomes kinetic energy of charged particles, appears therefore more suitable for direct conversion. Since they have lower reactivity than the D-T reaction, they need a larger βB 2 0 to give sufficiently high fusion power density. Because of this, the fusion configurations spherical torus (ST) and field-reversed configuration (FRC), where high β values are possible, appear interesting. Rosenbluth and Hinton come to the conclusion that efficient direct conversion isn't possible in closed field line systems and that open geometries, which facilitate direct conversion, provide inadequate confinement for D- 3 He. It is confirmed in this study that it doesn't seem possible to achieve as high direct conversion efficiency in closed systems as in open systems. ST and FRC fusion power plants that utilize direct conversion seem however interesting. Calculations with the help of Maple indicate that the reactor parameters needed for a D-D ST and a D 3 He ST hopefully are possible to achieve. The best energy conversion option for a D-D or D 3 He ST appears to be direct electrodynamic conversion (DEC) together with ordinary thermal conversion or liquid metal MHD conversion (LMMHD). For a D
Direct conversion of fusion energy

Energy Technology Data Exchange (ETDEWEB)

Johansson, Markus

2003-03-01

Deuterium and tritium are expected to be used as fuel in the first fusion reactors. Energy is released as kinetic energy of ions and neutrons, when deuterium reacts with tritium. One way to convert the kinetic energy to electrical energy, is to let the ions and neutrons hit the reactor wall and convert the heat that is caused by the particle bombardment to electrical energy with ordinary thermal conversion. If the kinetic energy of the ions instead is converted directly to electrical energy, a higher efficiency of the energy conversion is possible. The majority of the fusion energy is released as kinetic energy of neutrons, when deuterium reacts with tritium. Fusion reactions such as the D-D reactions, the D-{sup 3}He reaction and the p-{sup 11}B reaction, where a larger part of the fusion energy becomes kinetic energy of charged particles, appears therefore more suitable for direct conversion. Since they have lower reactivity than the D-T reaction, they need a larger {beta}B{sup 2}{sub 0} to give sufficiently high fusion power density. Because of this, the fusion configurations spherical torus (ST) and field-reversed configuration (FRC), where high {beta} values are possible, appear interesting. Rosenbluth and Hinton come to the conclusion that efficient direct conversion isn't possible in closed field line systems and that open geometries, which facilitate direct conversion, provide inadequate confinement for D-{sup 3}He. It is confirmed in this study that it doesn't seem possible to achieve as high direct conversion efficiency in closed systems as in open systems. ST and FRC fusion power plants that utilize direct conversion seem however interesting. Calculations with the help of Maple indicate that the reactor parameters needed for a D-D ST and a D{sub 3} He ST hopefully are possible to achieve. The best energy conversion option for a D-D or D{sub 3} He ST appears to be direct electrodynamic conversion (DEC) together with ordinary thermal conversion
Converting higher to lower boiling hydrocarbons. [Australian patent

Energy Technology Data Exchange (ETDEWEB)

1937-06-16

To transform or convert higher boiling hydrocarbons into lower boiling hydrocarbons for the production of motor fuel, the hydrocarbons are maintained in vapor phase until the desired conversion has been effected and the separation of the high from low boiling hydrocarbons is carried out by utilization of porous contact material with a preferential absorption for the former. The vapor is passed by supply line to a separator containing the porous material and heated to 750 to 950/sup 0/F for a few seconds, the higher boiling parts being retained by the porous material and the lower passing to a vent line. The latter is closed and the vapor supply cut off and an ejecting medium is passed through a line to carry the higher boiling parts to an outlet line from which it may be recycled through the apparatus. The porous mass may be regenerated by introducing medium from a line that carries off impurities to another line. A modified arrangement shows catalytic cracking apparatus through which the vaporized material is passed on the way to the separators.

Sources of polyaromatic hydrocarbons (PAH); Kildebestemmelse af polyaromatiske kulbrinter (PAH)

Energy Technology Data Exchange (ETDEWEB)

Egsgaard, H. [Forskningscenetr Risoe, Ald. for Plantebiologi og Biokemi (DK); Larsen, E. [Forskningscenter Risoe, Ald. for Optic og Fluid Dynamik (Denmark)

2000-03-01

Aromatic hydrocarbons including PAH compounds are thermally and chemically very stable compounds and are formed by gasification/pyrolysis of biomass. With reference to the tar compounds present in the produced gas from updraft gasifiers the sources responsible for the formation of naphthalene and poly-aromatic hydrocarbons have been investigated. The focus has been on thermal and oxidative conversions of compounds related to the lignin building blocks. Thus, phenols, 2-methoxy-phenols and 4-substituted-2-methoxy-phenols were investigated by introducing water solutions of the compounds into a continuos flow system operating in the temperature range 600-850 deg. C. The pyrolysis products were identified by GC/MS. The tar compounds reveal a well-defined and characteristic thermal transformation. Phenol is a strong source to naphthalene and indenes while 2-methoxyphenols are sources to aromatic oxo-compounds such as cinnamaldehyde. More complex systems are sources to higer PAH compounds. Thus, oligomers of phenol and 2-methoxyphenol give dibenzofuran and oligomers of isoeugenol are important sources to acenaphthylene. It is characteristic that the simple tar compounds investigated undergo loss of CO and hereby loss of the aromatic structure. The intermediary compounds are very reactive cyclo-pentadienes entering Diels-Alder reactions. The later products are transformed to aromatic compounds. The results may facilitate the determination of optimum conditions for updraft gasifiers and hence a reduction of PAH formation. (au)
Chemical conversion pathways and kinetic modeling for the OH-initiated reaction of triclosan in gas-phase.

Science.gov (United States)

Zhang, Xue; Zhang, Chenxi; Sun, Xiaomin; Kang, Lingyan; Zhao, Yan

2015-04-10

As a widely used antimicrobial additive in daily consumption, attention has been paid to the degradation and conversion of triclosan for a long time. The quantum chemistry calculation and the canonical variational transition state theory are employed to investigate the mechanism and kinetic property. Besides addition and abstraction, oxidation pathways and further conversion pathways are also considered. The OH radicals could degrade triclosan to phenols, aldehydes, and other easily degradable substances. The conversion mechanisms of triclosan to the polychlorinated dibenzopdioxin and furan (PCDD/Fs) and polychlorinated biphenyls (PCBs) are clearly illustrated and the toxicity would be strengthened in such pathways. Single radical and diradical pathways are compared to study the conversion mechanism of dichlorodibenzo dioxin (DCDD). Furthermore, thermochemistry is discussed in detail. Kinetic property is calculated and the consequent ratio of k add/k total and k abs/k total at 298.15 K are 0.955 and 0.045, respectively. Thus, the OH radical addition reactions are predominant, the substitute position of OH radical on triclosan is very important to generate PCDD and furan, and biradical is also a vital intermediate to produce dioxin.
Chemical Conversion Pathways and Kinetic Modeling for the OH-Initiated Reaction of Triclosan in Gas-Phase

Directory of Open Access Journals (Sweden)

Xue Zhang

2015-04-01

Full Text Available As a widely used antimicrobial additive in daily consumption, attention has been paid to the degradation and conversion of triclosan for a long time. The quantum chemistry calculation and the canonical variational transition state theory are employed to investigate the mechanism and kinetic property. Besides addition and abstraction, oxidation pathways and further conversion pathways are also considered. The OH radicals could degrade triclosan to phenols, aldehydes, and other easily degradable substances. The conversion mechanisms of triclosan to the polychlorinated dibenzopdioxin and furan (PCDD/Fs and polychlorinated biphenyls (PCBs are clearly illustrated and the toxicity would be strengthened in such pathways. Single radical and diradical pathways are compared to study the conversion mechanism of dichlorodibenzo dioxin (DCDD. Furthermore, thermochemistry is discussed in detail. Kinetic property is calculated and the consequent ratio of kadd/ktotal and kabs/ktotal at 298.15 K are 0.955 and 0.045, respectively. Thus, the OH radical addition reactions are predominant, the substitute position of OH radical on triclosan is very important to generate PCDD and furan, and biradical is also a vital intermediate to produce dioxin.
Temperature dependence of He(2 3PJ) reactions: Collision-induced mixing and conversion to He2( 3Πg) molecules

International Nuclear Information System (INIS)

Zhao, X.; Soletsky, P.A.; Bryan, W.H.; Dunning, F.B.; Walters, G.K.

1993-01-01

The rate coefficients for mixing between He(2 3 P J, MJ) levels during collisions with ground-state helium atoms and for conversion of He(2 3 P J ) atoms to He 2 (b 3 Π g ) molecules via three-body reactions in helium gas have been investigated over the temperature range 1.6--300 K. The measured rate coefficients for collisionally induced P-state mixing decrease slowly with decreasing temperature, from (1.8±0.5)x10 -9 cm 3 s -1 at 300 K to (4.5±0.5)x10 -10 cm 3 s -1 at 4.2 K. The rate coefficients for the production of He 2 (b 3 Π g ) molecules via three-body reactions are observed to increase with decreasing temperature and are described by the relation k P congruent(2.5+267T -1 )x10 -32 cm 6 s -1 . This behavior, which is very different from that noted in earlier studies of the conversion of He(2 3 S 1 ) atoms to He 2 (a 3 Σ u + ) molecules through three-body reactions, suggests that the reaction is not thermally activated
Process for preparing hydrocarbons

Energy Technology Data Exchange (ETDEWEB)

Krauch, C; Anther, E; Pier, M

1926-04-07

A process is described for the conversion of coal of all kinds, wood, oil, shale, as well as other carbonaceous materials into liquid hydrocarbons in two steps, characterized by treatment of the coal and so forth with a stream of hydrogen or hydrogen-containing gases at raised temperatures and raised pressures and producing a tarry product which, after separation of the ashlike residue, is converted by a further treatment, in the presence of catalysts, with hydrogen or hydrogen-containing gases at raised temperature and pressure, largely into low-boiling products.
The coupling effect of gas-phase chemistry and surface reactions on oxygen permeation and fuel conversion in ITM reactors

KAUST Repository

Hong, Jongsup; Kirchen, Patrick; Ghoniem, Ahmed F.

2015-01-01

© 2015 Elsevier B.V. The effect of the coupling between heterogeneous catalytic reactions supported by an ion transport membrane (ITM) and gas-phase chemistry on fuel conversion and oxygen permeation in ITM reactors is examined. In ITM reactors
Controlling Solid–Liquid Conversion Reactions for a Highly Reversible Aqueous Zinc–Iodine Battery

Energy Technology Data Exchange (ETDEWEB)

Pan, Huilin; Li, Bin; Mei, Donghai; Nie, Zimin; Shao, Yuyan; Li, Guosheng; Li, Xiaohong S.; Han, Kee Sung; Muller, Karl T.; Sprenkle, Vincent L.; Liu, Jun

2017-10-30

Aqueous rechargeable batteries are desirable for many energy storage applications due to their low cost and high safety. However, low capacity and short cycle life are the significant obstacles to their practical applications. Here, we demonstrate a highly reversible aqueous zinc-iodine battery using encapsulated iodine in microporous active carbon fibers (ACFs) as cathode materials through the rational control of solid-liquid conversion reactions. The experiments and density function theory (DFT) calculations were employed to investigate the effects of solvents and properties of carbon hosts, e.g. pore size, surface chemistries, on the adsorption of iodine species. The rational manipulation of the competition between the adsorption in carbon and solvation in electrolytes for iodine species is responsible for the high reversibility and cycling stability. The zinc-iodine batteries deliver a high capacity of 180 mAh g-1 at 1C and a stable cycle life over 3000 cycles with ~90% capacity retention as well as negligible self-discharge. We believe the principles for stabilizing the zinc-iodine system could provide new insight into conversion systems such as Li-S systems.
Modeling the Influence of Diffusion-Controlled Reactions and Residual Termination and Deactivation on the Rate and Control of Bulk ATRP at High Conversions

Directory of Open Access Journals (Sweden)

Ali Mohammad Rabea

2015-04-01

Full Text Available In high-conversion atom transfer radical polymerization (ATRP, all the reactions, such as radical termination, radical deactivation, dormant chain activation, monomer propagation, etc. could become diffusion controlled sooner or later, depending on relative diffusivities of the involved reacting species. These diffusion-controlled reactions directly affect the rate of polymerization and the control of polymer molecular weight. A model is developed to investigate the influence of diffusion-controlled reactions on the high conversion ATRP kinetics. Model simulation reveals that diffusion-controlled termination slightly increases the rate, but it is the diffusion-controlled deactivation that causes auto-acceleration in the rate (“gel effect” and loss of control. At high conversions, radical chains are “trapped” because of high molecular weight. However, radical centers can still migrate through (1 radical deactivation–activation cycles and (2 monomer propagation, which introduce “residual termination” reactions. It is found that the “residual termination” does not have much influence on the polymerization kinetics. The migration of radical centers through propagation can however facilitate catalytic deactivation of radicals, which improves the control of polymer molecular weight to some extent. Dormant chain activation and monomer propagation also become diffusion controlled and finally stop the polymerization when the system approaches its glass state.
Electrochemical removal of NOx and hydrocarbons

DEFF Research Database (Denmark)

Friedberg, Anja Zarah

on the electrodes during polarisation, probably because of strong adsorption of the hydrocarbon relative to NO. On LSF/CGO electrode the impregnation of ionic conducting material increased the oxidation of NO to NO2 which is an important step before nitrogen formation. The propene inhibited this reaction because....... This could only be done if the electrode was impregnated with BaO. The nitrate formation did not seem to be inhibited by the presence of the hydrocarbon. However, the oxidation of propene was inhibited by the BaO because the active sites for oxidations were partially covered by the BaO nanoparticles...
Partial oxidation of jet fuels over Rh/Al{sub 2}O{sub 3}. Design and reaction kinetics of sulfur-containing surrogates

Energy Technology Data Exchange (ETDEWEB)

Baer, Julian Nicolaas

2016-07-01

The conversion of logistic fuels via catalytic partial oxidation (CPOX) on Rh/Al{sub 2}O{sub 3} at short contact times is an efficient method for generating hydrogen-rich synthesis gas. Depending on the inlet conditions, fuel, and catalyst, high syngas yields, low by-product formation, and rates of high fuel conversion can be achieved. CPOX is relevant for mobile hydrogen generation, e.g., on board of airplanes in order to increase the fuel efficiency via fuel cell-based auxiliary power units. Jet fuels contain hundreds of different hydrocarbons and a significant amount of sulfur. The hydrocarbon composition and sulfur content of a jet fuel vary depending on distributor, origin, and refinement of the crude oil. Little is known about the influence of the various compounds on the synthesis-gas yield and the impact of sulfur on the product yield. In this work, the influence of three main chemical compounds of a jet fuel (aromatics, alkanes, and sulfur compounds) on syngas selectivity, the catalyst deactivation process, and reaction sequence is unraveled. As representative components of alkanes and aromatics, n-dodecane and 1,2,4-trimethylbenzene were chosen for ex-situ and in-situ investigations on the CPOX over Rh/Al{sub 2}O{sub 3}, respectively. Additionally, for a fixed paraffin-to-aromatics ratio, benzothiophene or dibenzothiophene were added as a sulfur component in three different concentrations. The knowledge gained about the catalytic partial oxidation of jet fuels and their surrogates is used to identify requirements for jet fuels in mobile applications based on CPOX and to optimize the overall system efficiency. The results show an influence of the surrogate composition on syngas selectivity. The tendency for syngas formation increases with higher paraffin contents. A growing tendency for by-product formation can be observed with increasing aromatics contents in the fuel. The impact of sulfur on the reaction system shows an immediate change in the product
Biogeochemistry of Halogenated Hydrocarbons

Science.gov (United States)

Adriaens, P.; Gruden, C.; McCormick, M. L.

2003-12-01

Halogenated hydrocarbons originate from both natural and industrial sources. Whereas direct anthropogenic emissions to the atmosphere and biosphere are often easy to assess, particularly when they are tied to major industrial activities, the attribution of emissions to other human activities (e.g., biomass burning), diffuse sources (e.g., atmospheric discharge, run off), and natural production (e.g., soils, fungi, algae, microorganisms) are difficult to quantify. The widespread occurrence of both alkyl and aryl halides in groundwater, surface water, soils, and various trophic food chains, even those not affected by known point sources, suggests a substantial biogeochemical cycling of these compounds (Wania and Mackay, 1996; Adriaens et al., 1999; Gruden et al., 2003). The transport and reactive fate mechanisms controlling their reactivity are compounded by the differences in sources of alkyl-, aryl-, and complex organic halides, and the largely unknown impact of biogenic processes, such as enzymatically mediated halogenation of organic matter, fungal production of halogenated hydrocarbons, and microbial or abiotic transformation reactions (e.g., Asplund and Grimvall, 1991; Gribble, 1996; Watling and Harper, 1998; Oberg, 2002). The largest source may be the natural halogenation processes in the terrestrial environment, as the quantities detected often exceed the amount that can be explained by human activities in the surrounding areas ( Oberg, 1998). Since biogeochemical processes result in the distribution of a wide range of halogenated hydrocarbon profiles, altered chemical structures, and isomer distributions in natural systems, source apportionment (or environmental forensics) can often only be resolved using multivariate statistical methods (e.g., Goovaerts, 1998; Barabas et al., 2003; Murphy and Morrison, 2002).This chapter will describe the widespread occurrence of halogenated hydrocarbons, interpret their distribution and biogeochemical cycling in light of
Four-body conversion of atomic helium ions

International Nuclear Information System (INIS)

de Vries, C.P.; Oskam, H.J.

1980-01-01

The conversion of atomic helium ions into molecular ions was studied in pure helium and in helium-neon mixtures containing between 0.1 at. % and 50 at. % neon. The experiments showed that the termolecular conversion reaction, He + +2He → He 2 + +He, is augmented by the four-body conversion reaction He + +3He → products, where the products could include either He 2 + or He 3 + ions. Conversion rate coefficients of (5.7 +- 0.8) x 10 -32 cm 6 sec -1 and (2.6 +- 0.4) x 10 -49 cm 9 sec -1 were found for the termolecular and four-body conversion reactions, respectively. In addition, rate coefficients for the following Ne + conversion reactions were measured: Ne + +He+He → (HeNe) + +He, (2.3 +- 0.1) x 10 -32 cm 6 sec -1 ; Ne + +He+Ne → (HeNe) + +Ne or Ne 2 + +He, (8.0 +- 0.8) x 10 -32 cm 6 sec -1 ; and Ne + +Ne+Ne → Ne 2 + +Ne, (5.1 +- 0.3) x 10 -32 cm 6 sec -1 . All rate coefficients are at a gas temperature of 295 K
Microbial production of gaseous hydrocarbons

Energy Technology Data Exchange (ETDEWEB)

Fukuda, Hideo

1987-10-20

Microbial production of ethylene, isobutane and a saturated gaseous hydrocarbon mixture was described. Microbial ethylene production was studied with Penicillium digitatum IFO 9372 and a novel pathway of the ethylene biosynthesis through alpha-ketoglutarate was proposed. Rhodotorula minuta IFO 1102 was selected for the microbial production of isobutane and the interesting actions of L-leucine and L-phenylalanine for the isobutane production were found. It was finally presented about the microbial production of a saturated gaseous hydrocarbon mixture with Rhizopus japonicus IFO 4758 was described. A gas mixture was produced through a chemical reaction of SH compounds and some cellular component such as squalene under aerobic conditions. (4 figs, 7 tabs, 41 refs)
Catalytic treatment of hydrocarbon oils

Energy Technology Data Exchange (ETDEWEB)

1940-02-23

A process is described for increasing the octane number of a hydrocarbon oil. The substance is subjected under pressure to a temperature between 800 and 1100/sup 0/C. Catalysts include metal compounds of Groups IV, V, Vi, or VIII (Group VI is perferred). Experiments are performed under a hydrogen atmosphere. Reaction time, temperature, pressure, and partial pressure of the hydrogen are adjusted so that there will be no net hydrogen consumption. The reaction gases (including the products) are recycled in whole or in part to supply the hydrogen gas required.
Catalytic conversion reactions mediated by single-file diffusion in linear nanopores: hydrodynamic versus stochastic behavior.

Science.gov (United States)

Ackerman, David M; Wang, Jing; Wendel, Joseph H; Liu, Da-Jiang; Pruski, Marek; Evans, James W

2011-03-21

We analyze the spatiotemporal behavior of species concentrations in a diffusion-mediated conversion reaction which occurs at catalytic sites within linear pores of nanometer diameter. Diffusion within the pores is subject to a strict single-file (no passing) constraint. Both transient and steady-state behavior is precisely characterized by kinetic Monte Carlo simulations of a spatially discrete lattice-gas model for this reaction-diffusion process considering various distributions of catalytic sites. Exact hierarchical master equations can also be developed for this model. Their analysis, after application of mean-field type truncation approximations, produces discrete reaction-diffusion type equations (mf-RDE). For slowly varying concentrations, we further develop coarse-grained continuum hydrodynamic reaction-diffusion equations (h-RDE) incorporating a precise treatment of single-file diffusion in this multispecies system. The h-RDE successfully describe nontrivial aspects of transient behavior, in contrast to the mf-RDE, and also correctly capture unreactive steady-state behavior in the pore interior. However, steady-state reactivity, which is localized near the pore ends when those regions are catalytic, is controlled by fluctuations not incorporated into the hydrodynamic treatment. The mf-RDE partly capture these fluctuation effects, but cannot describe scaling behavior of the reactivity.
Insights into hydrocarbon formation by nitrogenase cofactor homologs.

Science.gov (United States)

Lee, Chi Chung; Hu, Yilin; Ribbe, Markus W

2015-04-14

The L-cluster is an all-iron homolog of nitrogenase cofactors. Driven by europium(II) diethylenetriaminepentaacetate [Eu(II)-DTPA], the isolated L-cluster is capable of ATP-independent reduction of CO and CN(-) to C1 to C4 and C1 to C6 hydrocarbons, respectively. Compared to its cofactor homologs, the L-cluster generates considerably more CH4 from the reduction of CO and CN(-), which could be explained by the presence of a "free" Fe atom that is "unmasked" by homocitrate as an additional site for methanation. Moreover, the elevated CH4 formation is accompanied by a decrease in the amount of longer hydrocarbons and/or the lengths of the hydrocarbon products, illustrating a competition between CH4 formation/release and C-C coupling/chain extension. These observations suggest the possibility of designing simpler synthetic clusters for hydrocarbon formation while establishing the L-cluster as a platform for mechanistic investigations of CO and CN(-) reduction without complications originating from the heterometal and homocitrate components. Nitrogenase is a metalloenzyme that is highly complex in structure and uniquely versatile in function. It catalyzes two reactions that parallel two important industrial processes: the reduction of nitrogen to ammonia, which parallels the Haber-Bosch process in ammonia production, and the reduction of carbon monoxide to hydrocarbons, which parallels the Fischer-Tropsch process in fuel production. Thus, the significance of nitrogenase can be appreciated from the perspective of the useful products it generates: (i) ammonia, the "fixed" nitrogen that is essential for the existence of the entire human population; and (ii) hydrocarbons, the "recycled" carbon fuel that could be used to directly address the worldwide energy shortage. This article provides initial insights into the catalytic characteristics of various nitrogenase cofactors in hydrocarbon formation. The reported assay system provides a useful tool for mechanistic
Probing molecules on a surface by Cs+ reactive ion scattering: identification of C2Hx (x≤4) hydrocarbons

International Nuclear Information System (INIS)

Kang, H.; Lee, C.W.; Hwang, C.H.; Kim, C.M.

2003-01-01

We studied molecular species appearing in the reactions of ethylene on a Pt(1 1 1) surface by the technique of Cs + reactive ion scattering (Cs + RIS). Dehydrogenation reaction of ethylene was examined for a surface temperature range of 100-800 K, and the RIS result verified the well-known sequence of forming di-σ-bonded ethylene (-CH 2 -CH 2 -), ethylidyne (≡C-CH 3 ), CH, and then surface carbons, as the temperature increased. In particular, the intermediate species in the conversion of ethylene to ethylidyne was closely investigated, which showed the presence of an ethylidene intermediate (≡CH-CH 3 ). In a study of H/D exchange reactions between surface C 2 D 4 and H, we successfully identified the ethylenes in which several deuterium atoms were substituted by hydrogen (C 2 D 4-x H x ,x=0-4), and quantitatively determined their relative populations. These examples demonstrate the ability of the Cs + RIS method to identify small hydrocarbons and their isotope-exchanged species on surfaces
Catalytic conversion of light alkanes. Quarterly progress report, April 1--June 30, 1992

Energy Technology Data Exchange (ETDEWEB)

Lyons, J.E.

1992-06-30

The second Quarterly Report of 1992 on the Catalytic Conversion of Light Alkanes reviews the work done between April 1, 1992 and June 31, 1992 on the Cooperative Agreement. The mission of this work is to devise a new catalyst which can be used in a simple economic process to convert the light alkanes in natural gas to oxygenate products that can either be used as clean-burning, high octane liquid fuels, as fuel components or as precursors to liquid hydrocarbon uwspomdon fuel. During the past quarter we have continued to design, prepare, characterize and test novel catalysts for the mild selective reaction of light hydrocarbons with air or oxygen to produce alcohols directly. These catalysts are designed to form active metal oxo (MO) species and to be uniquely active for the homolytic cleavage of the carbon-hydrogen bonds in light alkanes producing intermediates which can form alcohols. We continue to investigate three molecular environments for the active catalytic species that we are trying to generate: electron-deficient macrocycles (PHASE I), polyoxometallates (PHASE II), and regular oxidic lattices including zeolites and related structures as well as other molecular surface structures having metal oxo groups (PHASE I).
Tuning functionality of photocatalytic materials: an infrared study on hydrocarbon oxidation

NARCIS (Netherlands)

Amrollahi Buky, Rezvaneh

2016-01-01

The focus of the research described in this thesis was on the engineering and design of effective photocatalysts able to catalyze the oxidative conversion of hydrocarbons. The prepared catalysts were synthesized by using different procedures involving sol gel precursors, and impregnation or
The Hydrocarbon Pool in Ethanol-to-Gasoline over HZSM-5 Catalysts

DEFF Research Database (Denmark)

Johansson, Roger; Hruby, S.L.; Hansen, Jeppe Rass

2009-01-01

It is shown that the conversion of ethanol-to-gasoline over an HZSM-5 catalyst yields essentially the same product distribution as for methanol-to-gasoline performed over the same catalyst. Interestingly, there is a significant difference between the identity of the hydrocarbon molecules trapped...... inside the HZSM-5 catalyst when ethanol is used as a feed instead of methanol. In particular, the hydrocarbon pool contains a significant amount of ethylsubstituted aromatics when ethanol is used as feedstock, but there remains only methyl-substituted aromatics in the product slate....

Electrochemical Routes towards Sustainable Hydrocarbon Fuels

DEFF Research Database (Denmark)

Mogensen, Mogens Bjerg

2012-01-01

The potential of renewable energy and possible solution to the intermittency problem of renewable energy sources like sun and wind are explained. The densest storage of energy is in the form of hydrocarbons. The most suitable method of conversion and storage within a foreseeable future is electro...... in the future. In spite of this, it is important to research and develop as many viable sustainable energy technologies as economical possible. © 2012 ECS - The Electrochemical Society ...
Sugarcane bagasse gasification: Global reaction mechanism of syngas evolution

International Nuclear Information System (INIS)

Ahmed, I.I.; Gupta, A.K.

2012-01-01

Highlights: ► Gasification of sugarcane bagasse has been investigated using a semi batch reactor. ► Global reaction mechanism combining pyrolysis and gasification reactions is presented. ► High flow rates of syngas supported fragmentation and secondary reactions. ► CO flow rate increased at higher heating rates at the expense of CO 2 production. ► At high temperatures merger between pyrolysis and char gasification occurs. -- Abstract: Steam gasification of sugarcane bagasse has been investigated. A semi batch reactor with a fixed amount of sugarcane bagasse sample placed in steady flow of high temperature steam at atmospheric pressure has been used. The gasification of bagasse was examined at reactor and steam temperatures of 800, 900 and 1000 °C. The evolution of syngas flow rate and chemical composition has been monitored. The evolution of chemical composition and total flow rate of the syngas has been used to formulate a global reaction mechanism. The mechanism combines pyrolysis reaction mechanisms from the literature and steam gasification/reforming reactions. Steam gasification steps include steam–hydrocarbons reforming, char gasification and water gas shift reactions. Evidence of fragmentation, secondary ring opening reactions and tertiary reactions resulting in formation of gaseous hydrocarbons is supported by higher flow rates of syngas and hydrogen at high heating rates and high reactor temperatures. Increase in carbon monoxide flow rate at the expense of carbon dioxide flow rate with the increase in reactor temperature has been observed. This increase in the ratio of CO/CO 2 flow rate confirms the production of CO and CO 2 from the competing reaction routes. At 1000 °C gasification a total merging between the pyrolysis step and the char gasification step has been observed. This is attributed to acceleration of char gasification reactions and acceleration of steam–hydrocarbons reforming reactions. These hydrocarbons are the precursors to
Formation of polycyclic aromatic hydrocarbons by ionizing radiations

International Nuclear Information System (INIS)

Perez, G.; Lilia, E.; Cristalli, A.

1986-01-01

Gaseous 0-terphenyl, 1-phenylnaphthalene, and 9-phenylanthracene were submitted to gamma rays. The yields of cyclization products, polycyclic aromatic hydrocarbons, show that at least one twentieth of the intermediates formed undergo intramolecular reaction. (author)
Process Design and Economics for the Conversion of Lignocellulosic Biomass to High Octane Gasoline: Thermochemical Research Pathway with Indirect Gasification and Methanol Intermediate

Energy Technology Data Exchange (ETDEWEB)

Tan, Eric [National Renewable Energy Lab. (NREL), Golden, CO (United States); Talmadge, M. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Dutta, Abhijit [National Renewable Energy Lab. (NREL), Golden, CO (United States); Hensley, Jesse [National Renewable Energy Lab. (NREL), Golden, CO (United States); Schaidle, Josh [National Renewable Energy Lab. (NREL), Golden, CO (United States); Biddy, Mary J. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Humbird, David [DWH Process Consulting, Denver, CO (United States); Snowden-Swan, Lesley J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Ross, Jeff [Harris Group, Inc., Seattle, WA (United States); Sexton, Danielle [Harris Group, Inc., Seattle, WA (United States); Yap, Raymond [Harris Group, Inc., Seattle, WA (United States); Lukas, John [Harris Group, Inc., Seattle, WA (United States)

2015-03-01

The U.S. Department of Energy (DOE) promotes research for enabling cost-competitive liquid fuels production from lignocellulosic biomass feedstocks. The research is geared to advance the state of technology (SOT) of biomass feedstock supply and logistics, conversion, and overall system sustainability. As part of their involvement in this program, the National Renewable Energy Laboratory (NREL) and the Pacific Northwest National Laboratory (PNNL) investigate the economics of conversion pathways through the development of conceptual biorefinery process models. This report describes in detail one potential conversion process for the production of high octane gasoline blendstock via indirect liquefaction (IDL). The steps involve the conversion of biomass to syngas via indirect gasification followed by gas cleanup and catalytic syngas conversion to a methanol intermediate; methanol is then further catalytically converted to high octane hydrocarbons. The conversion process model leverages technologies previously advanced by research funded by the Bioenergy Technologies Office (BETO) and demonstrated in 2012 with the production of mixed alcohols from biomass. Biomass-derived syngas cleanup via tar and hydrocarbons reforming was one of the key technology advancements as part of that research. The process described in this report evaluates a new technology area with downstream utilization of clean biomass-syngas for the production of high octane hydrocarbon products through a methanol intermediate, i.e., dehydration of methanol to dimethyl ether (DME) which subsequently undergoes homologation to high octane hydrocarbon products.
Application of Enzyme Coupling Reactions to Shift Thermodynamically Limited Biocatalytic Reactions

DEFF Research Database (Denmark)

Abu, Rohana; Woodley, John M.

2015-01-01

, it can be challenging to combine several engineered enzymes in vitro for the conversion of non-natural substrates. In this mini-review we focus on enzyme coupling reactions as a tool to alleviate thermodynamic constraints in synthetically useful biocatalytic reactions. The implications of thermodynamic...... shift the equilibrium of otherwise thermodynamically unfavourable reactions to give a higher conversion of the target product. By coupling an energetically unfavourable reaction with a more favourable one, the multi-enzyme cascade mimics the approach taken in nature in metabolic pathways. Nevertheless...
Gas-to-particle conversion in the atmospheric environment by radiation-induced and photochemical reactions

International Nuclear Information System (INIS)

Vohra, K.G.

1975-01-01

During the last few years a fascinating new area of research involving ionizing radiations and photochemistry in gas-to-particle conversion in the atmosphere has been developing at a rapid pace. Two problems of major interest and concern in which this is of paramount importance are: (1) radiation induced and photochemical aerosol formation in the stratosphere and, (2) role of radiations and photochemistry in smog formation. The peak in cosmic ray intensity and significant solar UV flux in the stratosphere lead to complex variety of reactions involving major and trace constituents in this region of the atmosphere, and some of these reactions are of vital importance in aerosol formation. The problem is of great current interest because the pollutant gases from industrial sources and future SST operations entering the stratosphere could increase the aerosol burden in the stratosphere and affect the solar energy input of the troposphere with consequent ecological and climatic changes. On the other hand, in the nuclear era, the atmospheric releases from reactors and processing plants could lead to changes in the cloud nucleation behaviour of the environment and possible increase in smog formation in the areas with significant levels of radiations and conventional pollutants. A review of the earlier work, current status of the problem, and conventional pollutants. A review of the earlier work, current status of the problem, and some recent results of the experiments conducted in the author's laboratory are presented. The possible mechanisms of gas-to-particle conversion in the atmosphere have been explained
The 11C-radioisotopic study of methanol conversion on V-MCM-41; the influence of methyl iodide on the transformation

International Nuclear Information System (INIS)

Sarkadi-Priboczki, E.; Szelecsenyi, F.; Kovacs, Z.; Solmaz, A.; Balci, S.; Dogu, T.

2007-01-01

Complete text of publication follows. The MCM-41 mesoporous material has Lewis and even Bronsted acid sites to produce dimethyl ether with some hydrocarbons, while over metal modified MCM-41 mostly formaldehyde and dimethoxy methane (i.e. methylal) or methyl formate are produced. In present experiments V incorporated basically mild acid sites of MCM-41 was prepared by low temperature direct synthesis. The V-MCM-41 has enough main active Lewis sites (by V-) to form formaldehyde and also light Bronsted acid sites to let the adsorbed formaldehyde eliminate and afterwards, with methanol, to form dimethoxy methane in nonoxidative environment. This V-MCM-41 has been tested by ethanol conversion in non-oxidative environments too and diethoxy methane as main product was detected. In present work the methanol conversion, as well as the methanol co-reaction with methyl iodide are studied from the same V-MCM-41 sample using 11 C-technique. The 11 C-labelled radioactive methanol has been already applied for determination of methanol conversion rates on Cu-modified MCM-41. The V-MCM-41 was prepared by direct hydrothermal synthesis method. The adsorption rate of 11 C-methanol and, after the reaction, the desorption rate of the remaining 11 C-derivatives on catalyst were continuously detected by gamma detectors. The derivatives were analyzed by radio-gas chromatography (gas chromatograph with FID coupled on-line with a radioactivity detector). Both dimethyl ether and hydrocarbon formation are also in slight degrees according to weak Lewis and Bronsted acidities. Since the conversion was carried out without added oxygen gas, only the frame oxygen can take part into catalysis. In presence of non-radioactive methyl iodide, the radioactive methanol is converted to radioactive methyl iodide on V-MCM-41. The radio-GC analysis confirmed that the iodide induced change of the reaction performance was reversible i.e. the radioactive methyl iodide was regenerated to non-radioactive methyl
Hydrothermal conversion of biomass

NARCIS (Netherlands)

Knezevic, D.

2009-01-01

This thesis presents research of hydrothermal conversion of biomass (HTC). In this process, hot compressed water (subcritical water) is used as the reaction medium. Therefore this technique is suitable for conversion of wet biomass/ waste streams. By working at high pressures, the evaporation of
Enhancement of in situ Remediation of Hydrocarbon Contaminated Soil

Energy Technology Data Exchange (ETDEWEB)

Palmroth, M.

2006-07-01

Approximately 750 000 sites of contaminated land exist across Europe. The harmful chemicals found in Finnish soils include heavy metals, oil products, polyaromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), chlorophenols, and pesticides. Petroleum and petroleum products enter soil from ruptured oil pipelines, land disposal of refinery products, leaking storage tanks and through accidents. PAH contamination is caused by the spills of coal tar and creosote from coal gasification and wood treatment sites in addition to oil spills. Cleanup of soil by bioremediation is cheaper than by chemical and physical processes. However, the cleaning capacity of natural attenuation and in situ bioremediation is limited. The purpose of this thesis was to find feasible options to enhance in situ remediation of hydrocarbon contaminants. The aims were to increase the bioavailability of the contaminants and microbial activity at the subsurface in order to achieve higher contaminant removal efficiency than by intrinsic biodegradation alone. Enhancement of microbial activity and decrease of soil toxicity during remediation were estimated by using several biological assays. The performance of these assays was compared in order to find suitable indicators to follow the progress of remediation. Phytoremediation and chemical oxidation are promising in situ techniques to increase the degradation of hydrocarbons in soil. Phytoremediation is plant-enhanced decontamination of soil and water. Degradation of hydrocarbons is enhanced in the root zone by increased microbial activity and through the detoxifying enzymes of plants themselves. Chemical oxidation of contaminants by Fenton's reaction can produce degradation products which are more biodegradable than the parent compounds. Fenton's reaction and its modifications apply solutions of hydrogen peroxide and iron for the oxidation of organic chemicals. The cost of oxidation can be reduced by aiming at partial instead of full
Improving Catalyst Efficiency in Bio-Based Hydrocarbon Fuels; NREL (National Renewable Energy Laboratory)

Energy Technology Data Exchange (ETDEWEB)

None

2015-06-01

This article investigates upgrading biomass pyrolysis vapors to form hydrocarbon fuels and chemicals using catalysts with different concentrations of acid sites. It shows that greater separation of acid sites makes catalysts more efficient at producing hydrocarbon fuels and chemicals. The conversion of biomass into liquid transportation fuels has attracted significant attention because of depleting fossil fuel reserves and environmental concerns resulting from the use of fossil fuels. Biomass is a renewable resource, which is abundant worldwide and can potentially be exploited to produce transportation fuels that are less damaging to the environment. This renewable resource consists of cellulose (40–50%), hemicellulose (25–35%), and lignin (16–33%) biopolymers in addition to smaller quantities of inorganic materials such as silica and alkali and alkaline earth metals (calcium and potassium). Fast pyrolysis is an attractive thermochemical technology for converting biomass into precursors for hydrocarbon fuels because it produces up to 75 wt% bio-oil,1 which can be upgraded to feedstocks and/or blendstocks for further refining to finished fuels. Bio-oil that has not been upgraded has limited applications because of the presence of oxygen-containing functional groups, derived from cellulose, hemicellulose and lignin, which gives rise to high acidity, high viscosity, low heating value, immiscibility with hydrocarbons and aging during storage. Ex situ catalytic vapor phase upgrading is a promising approach for improving the properties of bio-oil. The goal of this process is to reject oxygen and produce a bio-oil with improved properties for subsequent downstream conversion to hydrocarbons.
Laser-accelerated proton conversion efficiency thickness scaling

International Nuclear Information System (INIS)

Hey, D. S.; Foord, M. E.; Key, M. H.; LePape, S. L.; Mackinnon, A. J.; Patel, P. K.; Ping, Y.; Akli, K. U.; Stephens, R. B.; Bartal, T.; Beg, F. N.; Fedosejevs, R.; Friesen, H.; Tiedje, H. F.; Tsui, Y. Y.

2009-01-01

The conversion efficiency from laser energy into proton kinetic energy is measured with the 0.6 ps, 9x10 19 W/cm 2 Titan laser at the Jupiter Laser Facility as a function of target thickness in Au foils. For targets thicker than 20 μm, the conversion efficiency scales approximately as 1/L, where L is the target thickness. This is explained by the domination of hot electron collisional losses over adiabatic cooling. In thinner targets, the two effects become comparable, causing the conversion efficiency to scale weaker than 1/L; the measured conversion efficiency is constant within the scatter in the data for targets between 5 and 15 μm, with a peak conversion efficiency of 4% into protons with energy greater than 3 MeV. Depletion of the hydrocarbon contaminant layer is eliminated as an explanation for this plateau by using targets coated with 200 nm of ErH 3 on the rear surface. The proton acceleration is modeled with the hybrid-particle in cell code LSP, which reproduced the conversion efficiency scaling observed in the data.
One-step production of long-chain hydrocarbons from waste-biomass-derived chemicals using bi-functional heterogeneous catalysts.

Science.gov (United States)

Wen, Cun; Barrow, Elizabeth; Hattrick-Simpers, Jason; Lauterbach, Jochen

2014-02-21

In this study, we demonstrate the production of long-chain hydrocarbons (C8+) from 2-methylfuran (2MF) and butanal in a single step reactive process by utilizing a bi-functional catalyst with both acid and metallic sites. Our approach utilizes a solid acid for the hydroalkylation function and as a support as well as a transition metal as hydrodeoxygenation catalyst. A series of solid acids was screened, among which MCM-41 demonstrated the best combination of activity and stability. Platinum nanoparticles were then incorporated into the MCM-41. The Pt/MCM-41 catalyst showed 96% yield for C8+ hydrocarbons and the catalytic performance was stable over four reaction cycles of 20 hour each. The reaction pathways for the production of long-chain hydrocarbons is probed with a combination of infrared spectroscopy and steady-state reaction experiments. It is proposed that 2MF and butanal go through hydroalkylation first on the acid site followed by hydrodeoxygenation to produce the hydrocarbon fuels.
The Effect of Cell Phone Conversation on Drivers’ Reaction Time to Audio Stimulus: Investigating the Theory of Multiple Resources and Central Resource of Attention

Directory of Open Access Journals (Sweden)

Seyed Kazem Mousavi-Sadati

2011-01-01

Full Text Available Objective: This research was aimed at investigating the theory of multiple resources and central resource of attention on secondary task performance of talking with two types of cell phone during driving. Materials & Methods: Using disposal sampling, 25 male participants were selected and their reaction to auditory stimulus in three different driving conditions (no conversation with phone, conversation with handheld phone and hands-free phone were recorded. Driving conditions have been changed from a participant to another participant in order to control the sequence of tests and participants familiarity with the test conditions. Results: the results of data analysis with descriptive statistics and Mauchly’s Test of Sphericity, One- factor repeated measures ANOVA and Paired-Samples T test showed that different driving conditions can affect the reaction time (P0.001. Phone Conversation with hands-free phone increases drivers’ simple reaction time to auditory stimulus (P<0.001. Using handheld phone does not increase drivers’ reaction time to auditory stimulus over hands-free phone (P<0.001. Conclusion: The results confirmed that the performance quality of dual tasks and multiple tasks can be predicted by Four-dimensional multiple resources model of attention and all traffic laws in connection with the handheld phone also have to be spread to the use of hands-free phone.
Variations in the stable isotope ratios of specific aromatic and aliphatic hydrocarbons from coal conversion processes

Energy Technology Data Exchange (ETDEWEB)

McRae, C.; Snape, C.E.; Fallick, A.E. [University of Strathclyde, Glasgow (United Kingdom). Dept. of Pure and Applied Chemistry

1998-07-01

To establish the scope for applying gas chromatography-isotope ratio mass spectrometry ({sup {delta}-13}C GC-IRMS) to molecular recognition problems in coal utilisation, {sup 13}C/{sup 12}C isotope ratios were determined for n-alkanes and polycyclic aromatic hydrocarbons (PAHs) as a function of coal rank and process conditions. Six coals ranging from a lignite to a low volatile bituminous coal were subjected to chloroform extraction, fixed-bed pyrolysis under hydrogen pressure (hydropyrolysis) and fluidised-bed (flash) pyrolysis. No significant variations in the stable isotope ratios of n-alkanes were evident as a function of either rank or conversion regime. In contrast, the isotope ratios of PAHs show large variations with those for hydropyrolysis (-23 to -25 parts per thousand) being similar to the bulk values of the initial coals and being isotopically heavier (less negative) than their fluidised-bed pyrolysis counterparts by 2-3 parts per thousand. However, the PAHs from fluidised-bed pyrolysis, which resemble closely those obtained from high temperature coal carbonization, are still heavier (by 2-3 parts per thousand) than those from diesel particulates and coal gasification and combustion residues. This provides a firm basis for the source apportionment of airborne PAHs in the proximity of coking plants, particularly with no major variations in the PAH isotope ratios being found as a function of rank.
Biomass Conversion over Heteropoly Acid Catalysts

KAUST Repository

Zhang, Jizhe

2015-04-01

Biomass is a natural resource that is both abundant and sustainable. Its efficient utilization has long been the focus of research and development efforts with the aim to substitute it for fossil-based feedstock. In addition to the production of biofuels (e.g., ethanol) from biomass, which has been to some degree successful, its conversion to high value-added chemicals is equally important. Among various biomass conversion pathways, catalytic conversion is usually preferred, as it provides a cost-effective and eco-benign route to the desired products with high selectivities. The research of this thesis is focused on the conversion of biomass to various chemicals of commercial interest by selective catalytic oxidation. Molecular oxygen is chosen as the oxidant considering its low cost and environment friendly features in comparison with commonly used hydrogen peroxide. However, the activation of molecular oxygen usually requires high reaction temperatures, leading to over oxidation and thus lower selectivities. Therefore, it is highly desirable to develop effective catalysts for such conversion systems. We use kegging-type heteropoly acids (HPAs) as a platform for catalysts design because of their high catalytic activities and ease of medication. Using HPA catalysts allows the conversion taking place at relatively low temperature, which is beneficial to saving production cost as well as to improving the reaction selectivity. The strong acidity of HPA promotes the hydrolysis of biomass of giant molecules (e.g. cellulose), which is the first as well as the most difficult step in the conversion process. Under certain circumstances, a HPA combines the merits of homogeneous and heterogeneous catalysts, acting as an efficient homogeneous catalyst during the reaction while being easily separated as a heterogeneous catalyst after the reaction. We have successfully applied HPAs in several biomass conversion systems. Specially, we prepared a HPA-based bi-functional catalyst
Surface Plasmon-Assisted Solar Energy Conversion.

Science.gov (United States)

Dodekatos, Georgios; Schünemann, Stefan; Tüysüz, Harun

2016-01-01

The utilization of localized surface plasmon resonance (LSPR) from plasmonic noble metals in combination with semiconductors promises great improvements for visible light-driven photocatalysis, in particular for energy conversion. This review summarizes the basic principles of plasmonic photocatalysis, giving a comprehensive overview about the proposed mechanisms for enhancing the performance of photocatalytically active semiconductors with plasmonic devices and their applications for surface plasmon-assisted solar energy conversion. The main focus is on gold and, to a lesser extent, silver nanoparticles in combination with titania as semiconductor and their usage as active plasmonic photocatalysts. Recent advances in water splitting, hydrogen generation with sacrificial organic compounds, and CO2 reduction to hydrocarbons for solar fuel production are highlighted. Finally, further improvements for plasmonic photocatalysts, regarding performance, stability, and economic feasibility, are discussed for surface plasmon-assisted solar energy conversion.
Chemical deactivation of Ag/Al2O3 by sulphur for the selective reduction of NOx using hydrocarbons

International Nuclear Information System (INIS)

Houel, Valerie; Millington, Paul; Pollington, Stephen; Poulston, Stephen; Rajaram, Raj R.; Tsolakis, Athanasios

2006-01-01

The hydrocarbon-SCR activity of Ag/Al 2 O 3 catalysts is severely deactivated after low temperature (350 o C) sulphur ageing in the form of SO 2 exposure. Catalysts aged with SO 2 , NO and hydrocarbon present accumulate a significantly larger amount of SO 4 2- than those aged in the presence of only O 2 , H 2 O and SO 2 when exposed to an equivalent amount of S. Following sulphation of the catalyst most of the sulphur can be removed by a high temperature (600 o C) treatment in the reaction gas. Regeneration in the absence of hydrocarbon is ineffective. The hydrocarbon-SCR activity of the sulphated catalyst using model hydrocarbons such as n-C 8 H 18 can be restored after a high temperature pre-treatment in the reaction gases. However this desulphation process fails to regenerate the hydrocarbon-SCR activity when diesel fuel is used in the activity test. TPR studies show that a major fraction of the sulphur species present in the catalyst is removed by such pre-treatment, but the slight residual amount of sulphur is sufficient to inhibit the activation of the diesel fuel on the Ag catalyst. The nature of the hydrocarbon species present for the hydrocarbon-SCR reaction and during the regeneration strongly influences the activity. In general aromatics such as C 7 H 8 are less effective for reducing NO x and regenerating the sulphated catalyst. (author)
One-step Conversion of Levulinic Acid to Succinic Acid Using I2/t-BuOK System: The Iodoform Reaction Revisited.

Science.gov (United States)

Kawasumi, Ryosuke; Narita, Shodai; Miyamoto, Kazunori; Tominaga, Ken-Ichi; Takita, Ryo; Uchiyama, Masanobu

2017-12-21

The iodoform reaction has long been used as a qualitative test for acetyl and/or ethanol units in organic molecules. However, its synthetic applications are quite limited. Here, we describe a tuned iodoform reaction for oxidative demethylation reaction with I 2 and t-BuOK in t-BuOH, in which in situ-generated t-BuOI serves as the chemoselective iodinating agent. This system enables one-step conversion of levulinic acid to succinic acid, a major four-carbon chemical feedstock. This oxidative demethylation is also applicable to other compounds containing an acetyl group/ethanol unit, affording the corresponding carboxylic acids in a selective manner.
The Synthesis, Characterization and Catalytic Reaction Studies of Monodisperse Platinum Nanoparticles in Mesoporous Oxide Materials

Energy Technology Data Exchange (ETDEWEB)

Rioux, Robert M. [Univ. of California, Berkeley, CA (United States)

2006-01-01

A catalyst design program was implemented in which Pt nanoparticles, either of monodisperse size and/or shape were synthesized, characterized and studied in a number of hydrocarbon conversion reactions. The novel preparation of these materials enables exquisite control over their physical and chemical properties that could be controlled (and therefore rationally tuned) during synthesis. The ability to synthesize rather than prepare catalysts followed by thorough characterization enable accurate structure-function relationships to be elucidated. This thesis emphasizes all three aspects of catalyst design: synthesis, characterization and reactivity studies. The precise control of metal nanoparticle size, surface structure and composition may enable the development of highly active and selective heterogeneous catalysts.
Thermal theory of autowave processes in low-temperature solid-phase radiochemical reactions

International Nuclear Information System (INIS)

Barelko, V.V.; Barkalov, I.M.; Vaganov, D.A.; Zanin, A.M.; Kiryukhin, D.P.

1982-01-01

A new phenomenon in radiation cryochemistry concerning the class of autowave processes was previously discovered. It was observed in halogenation and hydrohalogenation of hydrocarbons and consisted of spontaneous, laminar propagation of a chemical transformation wave based on a frozen mixture of reagents previously irradiated with 60 Co γ-rays. The effect of the positive inverse correlation between the chemical conversion and brittle fracture of a solid sample of reagents is the phenomenological basis of the phenomenon; formation of fractures triggers a reactive process which takes place on their active surface (or in the layer adjacent to it), and the chemical reaction, in turn, stimulates the subsequent development of the process of decomposition. As a result, a single brittle fracture and chemical conversion wave which moves along the solid sample arises. Different mechanisms of generation of fracture surfaces under the effect of the reaction are possible. A difference in the densities of the initial reagents and the products of the reaction could be one of the causes of brittle fracture, and the thermal stresses induced by the exothermicity of the chemical processes could be another cause. The present work concerns the analysis of the features of the wave process which occurs based on the second, thermal mechanism. The analysis was conducted within the framework of a phenomenological approach which does not require specific definition of the nature of the chemical activation of the system during its brittle fracture

Free radical hydrogen atom abstraction from saturated hydrocarbons: A crossed-molecular-beams study of the reaction Cl + C{sub 3}H{sub 8} {yields} HCl + C{sub 3}H{sub 7}

Energy Technology Data Exchange (ETDEWEB)

Blank, D.A.; Hemmi, N.; Suits, A.G.; Lee, Y.T. [Lawrence Berkeley National Lab., CA (United States)

1997-04-01

The abstraction of hydrogen atoms from saturated hydrocarbons are reactions of fundamental importance in combustion as well as often being the rate limiting step in free radical substitution reactions. The authors have begun studying these reactions under single collision conditions using the crossed molecular beam technique on beamline 9.0.2.1, utilizing VUV undulator radiation to selectively ionize the scattered hydrocarbon free radical products (C{sub x}H{sub 2x+1}). The crossed molecular beam technique involves two reactant molecular beams fixed at 90{degrees}. The molecular beam sources are rotatable in the plane defined by the two beams. The scattered neutral products travel 12.0 cm where they are photoionized using the VUV undulator radiation, mass selected, and counted as a function of time. In the authors initial investigations they are using halogen atoms as protypical free radicals to abstract hydrogen atoms from small alkanes. Their first study has been looking at the reaction of Cl + propane {r_arrow} HCl + propyl radical. In their preliminary efforts the authors have measured the laboratory scattering angular distribution and time of flight spectra for the propyl radical products at collision energies of 9.6 kcal/mol and 14.9 kcal/mol.
Reaction selectivity studies on nanolithographically-fabricated platinum model catalyst arrays

Energy Technology Data Exchange (ETDEWEB)

Grunes, Jeffrey Benjamin [Univ. of California, Berkeley, CA (United States)

2004-05-01

In an effort to understand the molecular ingredients of catalytic activity and selectivity toward the end of tuning a catalyst for 100% selectivity, advanced nanolithography techniques were developed and utilized to fabricate well-ordered two-dimensional model catalyst arrays of metal nanostructures on an oxide support for the investigation of reaction selectivity. In-situ and ex-situ surface science techniques were coupled with catalytic reaction data to characterize the molecular structure of the catalyst systems and gain insight into hydrocarbon conversion in heterogeneous catalysis. Through systematic variation of catalyst parameters (size, spacing, structure, and oxide support) and catalytic reaction conditions (hydrocarbon chain length, temperature, pressures, and gas composition), the data presented in this dissertation demonstrate the ability to direct a reaction by rationally adjusting, through precise control, the design of the catalyst system. Electron beam lithography (EBL) was employed to create platinum nanoparticles on an alumina (Al₂O₃) support. The Pt nanoparticle spacing (100-150-nm interparticle distance) was varied in these samples, and they were characterized using x-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and atomic force microscopy (AFM), both before and after reactions. The TEM studies showed the 28-nm Pt nanoparticles with 100 and 150-nm interparticle spacing on alumina to be polycrystalline in nature, with crystalline sizes of 3-5 nm. The nanoparticle crystallites increased significantly after heat treatment. The nanoparticles were still mostly polycrystalline in nature, with 2-3 domains. The 28-nm Pt nanoparticles deposited on alumina were removed by the AFM tip in contact mode with a normal force of approximately 30 nN. After heat treatment at 500 C in vacuum for 3 hours, the AFM tip, even at 4000 nN, could not remove the platinum
Low severity conversion of activated coal

Energy Technology Data Exchange (ETDEWEB)

Hirschon, A.S.; Ross, D.S.

1990-01-01

The results suggest that coal contains regions with structural components significantly reactive under the hydrothermal environment. Although the specific mechanism for this process remains to be developed, this activity is reminiscent of findings in studies of accelerated maturation of oil shale, where hydrothermal treatment (hydrous pyrolysis) leads to the production of petroleum hydrocarbons. In line with what has been seen in the oil shale work, the pretreatment-generated hydrocarbons and phenols appear to represent a further or more complete maturation of some fraction of the organic material within the coal. These observations could have an impact in two areas. The first is in the area of coal structure, where immature, reactive regions have not been included in the structures considered at present. The second area of interest is the more practical one of conversions to coal liquids and pyrolytic tars. It seems clear that the hydrothermal pretreatment changes the coal in some manner that favorably affects the product quality substantially and, as in the CO/water liquefaction case, favorably affects the yields. The conversions of coals of lower rank, i.e., less mature coals, could particularly benefit in terms of both product quality and product quantity. The second portion of this project also shows important benefits to coal conversion technology. It deals with synthesizing catalysts designed to cleave the weak links in the coal structure and then linking these catalysts with the pretreatment methods in Task 2. The results show that highly dispersed catalysts can effectively be used to increase the yields of soluble material. An important aspect of highly dispersed catalysts are that they can effectively catalyze coal conversion even in poor liquefaction solvents, thus making them very attractive in processes such as coprocessing where inexpensive liquefaction media such as resids are used.
Hydrocarbon isotope detection by elastic peak electron spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Kostanovskiy, I.A., E-mail: kostanovskiyia@gmail.com [National Research University MPEI, Krasnokazarmennaya 14, 111250 Moscow (Russian Federation); Afanas’ev, V.P. [National Research University MPEI, Krasnokazarmennaya 14, 111250 Moscow (Russian Federation); Naujoks, D. [Max-Planck-Institut für Plasmaphysik, Teilinstitut Greifswald, Wendelsteinstraße 1, D-17491 Greifswald (Germany); Mayer, M. [Max-Planck-Institut für Plasmaphysik, D-85748 Garching (Germany)

2015-07-15

Highlights: • PCVD hydrocarbon coatings containing protium or deuterium are analyzed via NRA, ERD, XPS and EPES. • EPES analysis with modern electron energy analyzer SPECS Phoibos 225 shows a clear signal from the hydrogen isotopes. • Different primary energies and scattering angles help to quantify isotope content from EPES spectra. - Abstract: Experimental results on the hydrocarbon isotope analysis by elastic peak electron spectroscopy are presented. Amorphous hydrocarbon samples (a-C:H, a-C:D) are prepared by PCVD and analyzed by nuclear reaction analysis (NRA), elastic recoil detection analysis (ERD), X-ray photoelectron spectroscopy (XPS) and elastic peak electron spectroscopy (EPES). Electron energy spectra show a clear signal from the hydrogen isotopes deuterium and protium. Different incident energies and scattering geometries help to resolve plasmon and elastic energy losses.
Hydrocarbon isotope detection by elastic peak electron spectroscopy

International Nuclear Information System (INIS)

Kostanovskiy, I.A.; Afanas’ev, V.P.; Naujoks, D.; Mayer, M.

2015-01-01

Highlights: • PCVD hydrocarbon coatings containing protium or deuterium are analyzed via NRA, ERD, XPS and EPES. • EPES analysis with modern electron energy analyzer SPECS Phoibos 225 shows a clear signal from the hydrogen isotopes. • Different primary energies and scattering angles help to quantify isotope content from EPES spectra. - Abstract: Experimental results on the hydrocarbon isotope analysis by elastic peak electron spectroscopy are presented. Amorphous hydrocarbon samples (a-C:H, a-C:D) are prepared by PCVD and analyzed by nuclear reaction analysis (NRA), elastic recoil detection analysis (ERD), X-ray photoelectron spectroscopy (XPS) and elastic peak electron spectroscopy (EPES). Electron energy spectra show a clear signal from the hydrogen isotopes deuterium and protium. Different incident energies and scattering geometries help to resolve plasmon and elastic energy losses
New options for conversion of vegetable oils to alternative fuels

Energy Technology Data Exchange (ETDEWEB)

Demirbas, A.; Kara, H. [Selcuk University, Konya (Turkey). Department of Chemical Engineering

2006-05-15

Biodiesel from transesterification of vegetable oils is an excellent alternative fuel. There is, however, a need to develop a direct process for conversion of vegetable oils into gasoline-competitive biodiesel and other petroleum products. Methyl esters of vegetable oils have several outstanding advantages among other new-renewable and clean engine fuel alternatives. The purpose of the transesterification process is to lower the viscosity of vegetable oil. Compared to No. 2 diesel fuel, all of the vegetable oils are much more viscous, whereas methyl esters of vegetable oils are slightly more viscous. The methyl esters are more volatile than those of the vegetable oils. Conversion of vegetable oils to useful fuels involves the pyrolysis and catalytic cracking of the oils into lower molecular products. Pyrolysis produces more biogasoline than biodiesel fuel. Soap pyrolysis products of vegetable oils can be used as alternative diesel engine fuel. The soaps obtained from the vegetable oils can be pyrolyzed into hydrocarbon-rich products. Zinc chloride catalyst contributed greatly to high amounts of hydrocarbons in the liquid product. The yield of ZnCl2 catalytic conversion of the soybean oil reached the maximum 79.9% at 660 K. (author)
Analysis of graphite gasification by water vapor at different conversions

International Nuclear Information System (INIS)

Xiaowei, Luo; Xiaoyu, Yu; Suyuan, Yu; Jean-Charles, Robin

2014-01-01

Highlights: • Graphite was gasified at different conversions. • The reaction temperature influences on the dimensionless the reaction rate. • The thickness or radius influence on the dimensionless reaction rate. - Abstract: The gasification rate of porous solids varies with the conversions with the rate increasing to a maximum and then decreasing. Many graphite gasification experiments have illustrated that the maximum gasification rates occur at different conversions for different temperatures and sample geometries. Thus, the gasification rate is related to the conversion, temperature and geometry of the graphite. The influences of those factors were studied for the graphite gasification by water vapor. A theoretical analysis was done on the basis of several logical assumptions. The influence of temperatures on the reaction rate was investigated for plate-like and cylindrical graphite. The effects of thickness for a plate-like graphite sample and of radius for a cylindrical sample on the reaction rate were also studied theoretically. The results reveal that the maximum dimensionless reaction rate decreases with reaction temperature. The plate thickness or the cylinder radius also affects the maximum dimensionless reaction rate
One-step catalytic conversion of biomass-derived carbohydrates to liquid fuels

Science.gov (United States)

Sen, Ayusman; Yang, Weiran

2014-03-18

The invention relates to a method for manufacture of hydrocarbon fuels and oxygenated hydrocarbon fuels such as alkyl substituted tetrahydrofurans such as 2,5-dimethyltetrahydrofuran, 2-methyltetrahydrofuran, 5-methylfurfural and mixtures thereof. The method generally entails forming a mixture of reactants that includes carbonaceous material, water, a metal catalyst and an acid reacting that mixture in the presence of hydrogen. The reaction is performed at a temperature and for a time sufficient to produce a furan type hydrocarbon fuel. The process may be adapted to provide continuous manufacture of hydrocarbon fuels such as a furan type fuel.
Biomass Conversion to Hydrocarbon Fuels Using the MixAlcoTM Process Conversion de la biomasse en combustibles hydrocarbonés au moyen du procédé MixAlcoTM

Directory of Open Access Journals (Sweden)

Taco-Vasquez S.

2013-04-01

Full Text Available The MixAlcoTM process converts biomass to hydrocarbons (e.g., gasoline using the following generic steps: pretreatment, fermentation, descumming, dewatering, thermal ketonization, distillation, hydrogenation, oligomerization and saturation. This study describes the production of bio-gasoline from chicken manure and shredded office paper, both desirable feedstocks that do not require pretreatment. Using a mixed culture of microorganisms derived from marine soil, the biomass was fermented to produce a dilute aqueous solution of carboxylate salts, which were subsequently descummed and dried. The dry salts were thermally converted to raw ketones, which were distilled to remove impurities. Using Raney nickel catalyst, the distilled ketones were hydrogenated to mixed secondary alcohols ranging from C3 to C12. Using zeolite HZSM-5 catalyst, these alcohols were oligomerized to hydrocarbons in a plug -flow reactor. Finally, these unsaturated hydrocarbons were hydrogenated to produce a mixture of hydrocarbons that can be blended into commercial gasoline. Le procédé MixAlcoTM convertit la biomasse en hydrocarbures (par exemple, en essence selon les étapes génériques suivantes : prétraitement, fermentation, écumage, déshydratation, cétonisation thermique, distillation, hydrogénation, oligomérisation et saturation. Cette étude décrit la production de bioessence à partir de fumier de poulet et de papier en lambeaux, ces deux sources étant des matières premières convoitées ne nécessitant pas de prétraitement. À l’aide d’une culture mixte de microorganismes dérivés de sols marins, la biomasse a été soumise à une fermentation de manière à produire une solution aqueuse diluée de sels de carboxylates, ultérieurement écumés et séchés. Les sels séchés ont été thermiquement convertis en cétones brutes, ensuite distillées afin d’éliminer les impuretés. À l’aide du catalyseur à base de nickel de Raney, les c
Report compiled by Research Center for Carbonaceous Resources, Institute for Chemical Reaction Science, Tohoku University; Tohoku Daigaku Hanno Kagaku Kenkyusho tanso shigen hanno kenkyu center hokokusho

Energy Technology Data Exchange (ETDEWEB)

NONE

1994-04-01

The Research Center for Carbonaceous Resources was established in April 1991 for the purpose of developing a comprehensive process for converting carbonaceous resources into clean fuels or into materials equipped with advanced functions. In this report, the track records etc. of the center are introduced. Under study in the conversion process research department is the organization of a comprehensive coal conversion process which will be a combination of solvent extraction, catalytic decomposition, and catalytic gasification, whose goal is to convert coal in a clean way at high efficiency. Under study in the conversion catalyst research department are the development of a coal denitrogenation method, development of a low-temperature gasification method by use of inexpensive catalysts, synthesis of C{sub 2} hydrocarbons in a methane/carbon dioxide reaction, etc. Other endeavors under way involve the designing and development of new organic materials such as new carbon materials and a study of the foundation on which such efforts stand, that is, the study of the control of reactions between solids. Furthermore, in the study of interfacial reaction control, the contact gasification of coal, brown coal ion exchange capacity and surface conditions, carbonization of cation exchanged brown coal, etc., are being developed. (NEDO)
Hydrogen photoproduction by photoelectrochemical conversion

International Nuclear Information System (INIS)

Anon.

1989-01-01

The water-splitting reaction by photoelectrochemical processes has gained much more attention than any of many reactions proposed for solar generation of energy-rich molecules (fuels). The conversion efficiency of the photosystem is the key factor. The higher the efficiency, the more economically feasible will be the conversion scheme. The conversion efficiency is a function of the semiconductor properties, light intensity, spectral quality, properties of the electrolyte, counterelectrode, cell configuration, etc. The semiconductor parameters include band gap, absorption coefficient and diffusion length. The area and material used for a counterelectrode are important when considering polarization losses in a two-electrode system. Besides, the stability problem is also a very important one to meet the requirement for practical applications. This paper reviews some important issues on photoelectrochemical generation of hydrogen by water splitting. It includes energy conversion efficiency, market assessment and cost goal, state of the technology, and future directions for research
Chain chemical reactions during matrix devitrification

International Nuclear Information System (INIS)

Barkalov, I.M.

1980-01-01

Investigation results of chain reaction mechanisms, proceeding at devitrification of glass-like matrices under the effect of γ-irradiation are summarized. Peculiarities of kinetics and mechanism of chain reactions proceeding at devitrification are considered: hydrocarbon chlorination, polymerization of vinyl monomers, copolymerization and graft polymerization. Possible application aspects of the chain reaction conducting during matrix devitrification are also considered
NOVEL SUPPORTED BIMETALLIC CARBIDE CATALYSTS FOR COPROCESSING OF COAL WITH WASTE METERIALS

Energy Technology Data Exchange (ETDEWEB)

S. Ted Oyama; David F. Cox; Chunshan Song; Fred Allen; Weilin Wang; Viviane Schwartz; Xinqin Wang; Jianli Yang

2001-01-01

The overall objectives of this project are to explore the potential of novel monometallic and bimetallic Mo-based carbide catalysts for heavy hydrocarbon coprocessing, and to understand the fundamental chemistry related to the reaction pathways of coprocessing and the role of the catalysts in the conversion of heavy hydrocarbon resources into liquid fuels based on the model compound reactions.
Co-processing of standard gas oil and biocrude oil to hydrocarbon fuels

International Nuclear Information System (INIS)

Agblevor, Foster A.; Mante, O.; McClung, R.; Oyama, S.T.

2012-01-01

The major obstacle in thermochemical biomass conversion to hydrocarbon fuels using pyrolysis has been the high oxygen content and the poor stability of the product oils, which cause them to solidify during secondary processing. We have developed a fractional catalytic pyrolysis process to convert biomass feedstocks into a product termed “biocrude oils” (stable biomass pyrolysis oils) which are distinct from unstable conventional pyrolysis oils. The biocrude oils are stable, low viscosity liquids that are storable at ambient conditions without any significant increases in viscosity; distillable at both atmospheric pressure and under vacuum without char or solid formation. About 15 wt% biocrude oils containing 20–25% oxygen were blended with 85 wt% standard gas oil and co-cracked in an Advanced Catalyst Evaluation (ACE™) unit using fluid catalytic cracking (FCC) catalysts to produce hydrocarbon fuels that contain negligible amount of oxygen. For the same conversion of 70% for both the standard gas oil and the biocrude oil/gas oil blends, the product gasoline yield was 44 wt%, light cycle oil (LCO) 17 wt%, heavy cycle oil (HCO) 13 wt%, and liquefied petroleum gas (LPG) 16 wt%. However, the coke yield for the standard gas oil was 7.06 wt% compared to 6.64–6.81 wt% for the blends. There appeared to be hydrogen transfer from the cracking of the standard gas oil to the biocrude oil which subsequently eliminated the oxygen in the fuel without external hydrogen addition. We have demonstrated for the first time that biomass pyrolysis oils can be successfully converted into hydrocarbons without hydrogenation pretreatment. -- Highlights: ► The co-processed product had less than 1% oxygen content and contained biocarbons determined by 14 C analysis. ► The co-processing did not affect the yields of gasoline, LCO, and HCO. ► First demonstration of direct conversion of pyrolysis oils into drop-in hydrocarbon fuels.
Producing light hydrocarbons by destructive hydrogenation

Energy Technology Data Exchange (ETDEWEB)

Fohlen, J H

1928-06-20

A method of obtaining light hydrocarbons from fuels and natural or industrial carbonaceous materials by cracking under pressure from 5 to 200 atmospheres and within a temperature range of 200 to 1,000/sup 0/C, the cracking operation being assisted by the presence of catalysts such as metallic halides, simultaneously, with hydrogenation by means of nascent hydrogen in the reaction chamber.
Automatic reduction of the hydrocarbon reaction mechanisms in fusion edge plasmas

International Nuclear Information System (INIS)

Dauwe, A.; Tytgadt, M.; Reiter, D.; Baelmans, M.

2006-11-01

For predictions of the tritium inventory in future fusion devices like ITER, the amount of eroded carbon and the hydrogen concentrations in co-deposited hydrocarbon layers have to be predicted quantitatively. Predictions about the locations of co-deposited layers are also necessary in order to design deposition diagnostics and layer removal methods. This requires a detailed physical understanding of the erosion and carbon migration processes, and computer simulations. For accurate simulation the multi-species code EIRENE would require to include over 50 participating species. Because such a calculation is computationally prohibitive current codes are being reduced, typically in an ad hoc fashion. In this work the potential of the mathematically sound method of intrinsic low dimensional manifolds (ILDM) for computational speed-up of the hydrocarbon transport problem simulation is thoroughly investigated. It is basically the Monte Carlo implementation of EIRENE that makes this task so challenging. As the method can substantially ameliorate the results in comparison to the conventional reduction mechanisms a step towards ILDM-reduced kinetics is conceived and tested. (orig.)
Removal of polycyclic aromatic hydrocarbons in aqueous environment by chemical treatments: a review.

Science.gov (United States)

Rubio-Clemente, Ainhoa; Torres-Palma, Ricardo A; Peñuela, Gustavo A

2014-04-15

Due to their carcinogenic, mutagenic and teratogenic potential, the removal of polycyclic aromatic hydrocarbons (PAHs) from aqueous environment using physical, biological and chemical processes has been studied by several researchers. This paper reviews the current state of knowledge concerning PAHs including their physico-chemical properties, input sources, occurrence, adverse effects and conventional and alternative chemical processes applied for their removal from water. The mechanisms and reactions involved in each treatment method are reported, and the effects of various variables on the PAH degradation rate as well as the extent of degradation are also discussed. Extensive literature analysis has shown that an effective way to perform the conversion and mineralization of this type of substances is the application of advanced oxidation processes (AOPs). Furthermore, combined processes, particularly AOPs coupled with biological treatments, seem to be one of the best solutions for the treatment of effluents containing PAHs. Copyright © 2013 Elsevier B.V. All rights reserved.
Highly Efficient and Reproducible Nonfullerene Solar Cells from Hydrocarbon Solvents

KAUST Repository

Wadsworth, Andrew; Ashraf, Raja; Abdelsamie, Maged; Pont, Sebastian; Little, Mark; Moser, Maximilian; Hamid, Zeinab; Neophytou, Marios; Zhang, Weimin; Amassian, Aram; Durrant, James R.; Baran, Derya; McCulloch, Iain

2017-01-01

With chlorinated solvents unlikely to be permitted for use in solution-processed organic solar cells in industry, there must be a focus on developing nonchlorinated solvent systems. Here we report high-efficiency devices utilizing a low-bandgap donor polymer (PffBT4T-2DT) and a nonfullerene acceptor (EH-IDTBR) from hydrocarbon solvents and without using additives. When mesitylene was used as the solvent, rather than chlorobenzene, an improved power conversion efficiency (11.1%) was achieved without the need for pre- or post-treatments. Despite altering the processing conditions to environmentally friendly solvents and room-temperature coating, grazing incident X-ray measurements confirmed that active layers processed from hydrocarbon solvents retained the robust nanomorphology obtained with hot-processed chlorinated solvents. The main advantages of hydrocarbon solvent-processed devices, besides the improved efficiencies, were the reproducibility and storage lifetime of devices. Mesitylene devices showed better reproducibility and shelf life up to 4000 h with PCE dropping by only 8% of its initial value.
Highly Efficient and Reproducible Nonfullerene Solar Cells from Hydrocarbon Solvents

KAUST Repository

Wadsworth, Andrew

2017-06-01

With chlorinated solvents unlikely to be permitted for use in solution-processed organic solar cells in industry, there must be a focus on developing nonchlorinated solvent systems. Here we report high-efficiency devices utilizing a low-bandgap donor polymer (PffBT4T-2DT) and a nonfullerene acceptor (EH-IDTBR) from hydrocarbon solvents and without using additives. When mesitylene was used as the solvent, rather than chlorobenzene, an improved power conversion efficiency (11.1%) was achieved without the need for pre- or post-treatments. Despite altering the processing conditions to environmentally friendly solvents and room-temperature coating, grazing incident X-ray measurements confirmed that active layers processed from hydrocarbon solvents retained the robust nanomorphology obtained with hot-processed chlorinated solvents. The main advantages of hydrocarbon solvent-processed devices, besides the improved efficiencies, were the reproducibility and storage lifetime of devices. Mesitylene devices showed better reproducibility and shelf life up to 4000 h with PCE dropping by only 8% of its initial value.
The multichannel n-propyl + O2 reaction surface: Definitive theory on a model hydrocarbon oxidation mechanism

Science.gov (United States)

Bartlett, Marcus A.; Liang, Tao; Pu, Liang; Schaefer, Henry F.; Allen, Wesley D.

2018-03-01

The n-propyl + O2 reaction is an important model of chain branching reactions in larger combustion systems. In this work, focal point analyses (FPAs) extrapolating to the ab initio limit were performed on the n-propyl + O2 system based on explicit quantum chemical computations with electron correlation treatments through coupled cluster single, double, triple, and perturbative quadruple excitations [CCSDT(Q)] and basis sets up to cc-pV5Z. All reaction species and transition states were fully optimized at the rigorous CCSD(T)/cc-pVTZ level of theory, revealing some substantial differences in comparison to the density functional theory geometries existing in the literature. A mixed Hessian methodology was implemented and benchmarked that essentially makes the computations of CCSD(T)/cc-pVTZ vibrational frequencies feasible and thus provides critical improvements to zero-point vibrational energies for the n-propyl + O2 system. Two key stationary points, n-propylperoxy radical (MIN1) and its concerted elimination transition state (TS1), were located 32.7 kcal mol-1 and 2.4 kcal mol-1 below the reactants, respectively. Two competitive β-hydrogen transfer transition states (TS2 and TS2') were found separated by only 0.16 kcal mol-1, a fact unrecognized in the current combustion literature. Incorporating TS2' in master equation (ME) kinetic models might reduce the large discrepancy of 2.5 kcal mol-1 between FPA and ME barrier heights for TS2. TS2 exhibits an anomalously large diagonal Born-Oppenheimer correction (ΔDBOC = 1.71 kcal mol-1), which is indicative of a nearby surface crossing and possible nonadiabatic reaction dynamics. The first systematic conformational search of three hydroperoxypropyl (QOOH) intermediates was completed, uncovering a total of 32 rotamers lying within 1.6 kcal mol-1 of their respective lowest-energy minima. Our definitive energetics for stationary points on the n-propyl + O2 potential energy surface provide key benchmarks for future studies

Conversion Disorder Presenting As Neuritic Leprosy

Directory of Open Access Journals (Sweden)

Sayal SK

2000-01-01

Full Text Available Conversion disorder is not normally listed amongst the conditions in differential diagnosis of leprosy neuropathy. A case conversion reaction who was initially diagnosed as neuritic leprosy is reported. Patient responded to narcosuggestion and psychotherapy.
S-methylmethionine conversion to dimethylsulfoniopropionate: evidence for an unusual transamination reaction

International Nuclear Information System (INIS)

Rhodes, D.; Gage, D.A.; Cooper, A.J.L.; Hanson, A.D.

1997-01-01

Leaves of Wollastonia biflora (L.) DC. synthesize the osmoprotectant 3-dimethylsulfoniopropionate (DMSP) from methionine via S-methylmethionine (SMM) and 3-dimethylsulfoniopropionaldehyde (DMSP-ald); no other intermediates have been detected. To test whether the amino group of SMM is lost by transamination or deamination, [methyl-2H3, 15N]SMM was supplied to leaf discs, and 15N-labeling of amino acids was monitored, along with synthesis of [2H3]DMSP. After short incubations more 15N was incorporated into glutamate than into other amino acids, and the 15N abundance in glutamate exceeded that in the amide group of glutamine (Gln). This is more consistent with transamination than deamination, because deamination would be predicted to give greater labeling of Gln amide N due to reassimilation, via Gln synthetase, of the 15NH4+ released. This prediction was borne out by control experiments with 15NH4Cl. The transamination product of SMM, 4-dimethylsulfonio-2-oxobutyrate (DMSOB), is expected to be extremely unstable. This was confirmed by attempting to synthesize it enzymatically from SMM using L-amino acid oxidase or Gln transaminase K and from 4-methylthio-2-oxobutyrate using methionine S-methyltransferase. In each case, the reaction product decomposed rapidly, releasing dimethylsulfide. The conversion of SMM to DMSP-ald is therefore unlikely to involve a simple transamination that generates free DMSOB. Plausible alternatives are that DMSOB is channeled within a specialized transaminase-decarboxylase complex or that it exists only as the bound intermediate of a single enzyme catalyzing an unusual transamination-decarboxylation reaction
Effect of CO on NO and N2O conversions in nonthermal argon plasma

International Nuclear Information System (INIS)

Zhao Guibing; Argyle, Morris D.; Radosz, Maciej

2006-01-01

200-600 ppm of CO inhibit NO conversion in nonthermal Ar plasma, but do not produce N 2 O. However, 1.01% of CO has no effect on NO conversion, but produces N 2 O. In general, N 2 O conversion in Ar plasma decreases with increasing CO concentration. These experimental results cannot be explained by charge transfer reactions of Ar + . Selectivity analysis of all excited states of Ar possibly contributing to NO x conversion without and with CO suggests that only Ar( 3 P 2 ) contributes to NO x conversion and CO dissociation. A kinetic model of 43 reactions is required to model NO conversion or N 2 O conversion in Ar without CO, whereas 81 reactions are required to model NO conversion and N 2 O conversion in Ar with CO. At constant gas pressure, a single set of model parameters can predict NO conversion or N 2 O conversion without and with CO. All experimental results can be explained using a reaction mechanism in which excited neutral states of Ar are the only active species, which supports the conclusion that cations have a negligible impact on these nonthermal plasma reactions
Mathematical Simulation of High-Conversion Binary Copolymerization

Institute of Scientific and Technical Information of China (English)

JiangWei; QinJiguang

2005-01-01

A new model for mathematical simulation of high-conversion binary copolymerization was established by combination of the concept of the three stage polymerization model (TSPM) proposed by Qin et al. for bulk free radical homopolymerization with the North equation to describe high-conversion copolymerization reaction exhibiting a strong gel effect, and the mathematical expressions of this new model were derived. Like TSPM, the new model also assmnes that the whole course of binary copolymerization can be divided into three different stages: low conversion, gel effect and glass effect stages. In addition, the reaction rate constants and the initiator efficiency at each copolymerization stage do not vary with conversion. Based on the expressions derived, a plot method for determining the overall rate constants and critical conversions was proposed. The literature data on conversion history for styrene (St)-methyl methacrylate (MMA) and ethylene glycol dimethacrylate (EGDMA)-MMA copolymerizations were treated to examine the model, which shows that the model is satisfactory.
High Temperature Chemistry of Aromatic Hydrocarbons. Final Technical Report

Energy Technology Data Exchange (ETDEWEB)

Scott, Lawrence T. [Boston College, Chestnut Hill, MA (United States). Merkert Chemistry Center, Dept. of Chemistry

2017-05-15

The primary goal of this research was to uncover the principal reaction channels available to polycyclic aromatic hydrocarbons (PAHs) at high temperatures in the gas phase and to establish the factors that determine which channels will be followed in varying circumstances. New structure-property relationships for PAHs were also studied. The efficient production of clean energy from fossil fuels will remain a major component of the DOE mission until alternative sources of energy eventually displace coal and petroleum. Hydrocarbons constitute the most basic class of compounds in all of organic chemistry, and as the dominant species in fossil fuels, they figure prominently into the programs of the DOE. Much is already known about the normal chemistry of hydrocarbons under ambient conditions, but far less is known about their intrinsic chemistry at temperatures close to those reached during combustion. An understanding of the fundamental molecular transformations, rearrangements, and interconversions of PAHs at high temperatures in the gas phase, as revealed by careful studies on small, well-designed, molecular systems, provides insights into the underlying chemistry of many important processes that are more complex, such as the generation of energy by the combustion of fossil fuels, the uncatalyzed gasification and liquefaction of coal, the production of fullerenes in fuel-rich flames, and the formation of soot and carcinogenic pollutants in smoke (e.g., benzo[a]pyrene). The rational control of any of these processes, whether it be the optimization of a desirable process or the minimization of an undesirable one, requires a clear knowledge of the basic chemistry that governs the fate of the species involved. Advances in chemistry at the most fundamental level come about primarily from the discovery of new reactions and from new insights into how reactions occur. Harnessing that knowledge is the key to new technologies. The recent commercialization of a combustion
A numerical and experimental study of polycyclic aromatic hydrocarbons in a laminar diffusion flame

NARCIS (Netherlands)

Vogels - Verhoeven, L.M.; Andrade Oliveira, de M.H.; Lantz, A.; Li, B.; Li, Z.S.; Luijten, C.C.M.; Oijen, van J.A.; Aldén, M.; Goey, de L.P.H.

2013-01-01

During the process of biomass gasification tars are formed which exit the gasifier in vapor phase. Tar condensation creates problems like fouling and plugging of after-treatment, conversion and end-use equipment. Gasification tars consist mainly of Polycyclic Aromatic Hydrocarbons (PAHs). Former
Precipitation of the rare earth double sodium and rare earths from the sulfuric liquor and the conversion into rare earth hydroxides through meta ethic reaction

International Nuclear Information System (INIS)

Abreu, Renata D.; Oliveira, Ester F.; Brito, Walter de; Morais, Carlos A.

2007-01-01

This work presents the purification study of the rare earths through precipitation of rare earth and sodium (Na TR (SO 4 ) 2 . x H 2 O)) double sulfate and his conversion to rare earths hydroxide TR(OH) 3 by meta ethic reaction through the addition of sodium hydroxide solution to the solid double sulfate. The study used the sulfuric liquor as rare earth sample, generated in the chemical processing of the monazite with sulfuric acid by the Industrias Nucleares do Brasil - INB, Brazil, after the thorium and uranium extraction. The work investigated the influence of the main variables involved in the precipitation of Na TR(SO 4 ) 2 .xH 2 O and in the conversion for the TR(OH) 3 , as follows: type and excess of the precipitation agent, temperature and time reaction. The obtained solid composites were characterized by X-ray diffraction, infrared and chemical analysis. The double sulfate diffractogram indicated the Na TR(SO 4 ) 2 mono-hydrated. The characterization of the metatese products has shown that, for obtaining the complete conversion of NaTR(SO 4 ) 2 .H 2 O into TR(OH) 3 , the reaction must be hot processed (∼70 deg C) and with small excess of Na OH (≤ 5 percent). (author)
Fundamental spectroscopic studies of carbenes and hydrocarbon radicals

Energy Technology Data Exchange (ETDEWEB)

Gottlieb, C.A.; Thaddeus, P. [Harvard Univ., Cambridge, MA (United States)

1993-12-01

Highly reactive carbenes and carbon-chain radicals are studied at millimeter wavelengths by observing their rotational spectra. The purpose is to provide definitive spectroscopic identification, accurate spectroscopic constants in the lowest vibrational states, and reliable structures of the key intermediates in reactions leading to aromatic hydrocarbons and soot particles in combustion.
Selective transformation of syngas into gasoline-range hydrocarbons over mesoporous H-ZSM-5-supported cobalt nanoparticles.

Science.gov (United States)

Cheng, Kang; Zhang, Lei; Kang, Jincan; Peng, Xiaobo; Zhang, Qinghong; Wang, Ye

2015-01-26

Bifunctional Fischer-Tropsch (FT) catalysts that couple uniform-sized Co nanoparticles for CO hydrogenation and mesoporous zeolites for hydrocracking/isomerization reactions were found to be promising for the direct production of gasoline-range (C5-11 ) hydrocarbons from syngas. The Brønsted acidity results in hydrocracking/isomerization of the heavier hydrocarbons formed on Co nanoparticles, while the mesoporosity contributes to suppressing the formation of lighter (C1-4 ) hydrocarbons. The selectivity for C5-11 hydrocarbons could reach about 70 % with a ratio of isoparaffins to n-paraffins of approximately 2.3 over this catalyst, and the former is markedly higher than the maximum value (ca. 45 %) expected from the Anderson-Schulz-Flory distribution. By using n-hexadecane as a model compound, it was clarified that both the acidity and mesoporosity play key roles in controlling the hydrocracking reactions and thus contribute to the improved product selectivity in FT synthesis. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Characterization of cyanobacterial hydrocarbon composition and distribution of biosynthetic pathways.

Directory of Open Access Journals (Sweden)

R Cameron Coates

Full Text Available Cyanobacteria possess the unique capacity to naturally produce hydrocarbons from fatty acids. Hydrocarbon compositions of thirty-two strains of cyanobacteria were characterized to reveal novel structural features and insights into hydrocarbon biosynthesis in cyanobacteria. This investigation revealed new double bond (2- and 3-heptadecene and methyl group positions (3-, 4- and 5-methylheptadecane for a variety of strains. Additionally, results from this study and literature reports indicate that hydrocarbon production is a universal phenomenon in cyanobacteria. All cyanobacteria possess the capacity to produce hydrocarbons from fatty acids yet not all accomplish this through the same metabolic pathway. One pathway comprises a two-step conversion of fatty acids first to fatty aldehydes and then alkanes that involves a fatty acyl ACP reductase (FAAR and aldehyde deformylating oxygenase (ADO. The second involves a polyketide synthase (PKS pathway that first elongates the acyl chain followed by decarboxylation to produce a terminal alkene (olefin synthase, OLS. Sixty-one strains possessing the FAAR/ADO pathway and twelve strains possessing the OLS pathway were newly identified through bioinformatic analyses. Strains possessing the OLS pathway formed a cohesive phylogenetic clade with the exception of three Moorea strains and Leptolyngbya sp. PCC 6406 which may have acquired the OLS pathway via horizontal gene transfer. Hydrocarbon pathways were identified in one-hundred-forty-two strains of cyanobacteria over a broad phylogenetic range and there were no instances where both the FAAR/ADO and the OLS pathways were found together in the same genome, suggesting an unknown selective pressure maintains one or the other pathway, but not both.
Deep conversion of black oils with Eni Slurry technology

Energy Technology Data Exchange (ETDEWEB)

Panariti, Nicoletta; Rispoli, Giacomo

2010-09-15

Eni Slurry Technology represents a significant technological innovation in residue conversion and unconventional oils upgrading. EST allows the almost total conversion of heavy feedstocks into useful products, mainly transportation fuels, with a great major impact on the economic and environmental valorization of hydrocarbon resources. The peculiar characteristics of EST in terms of yields, products quality, absence of undesired by-products and feedstock flexibility constitute its superior economic and environmental attractiveness. The first full scale industrial plant based on this new technology will be realized in Eni's Sannazzaro refinery (23,000 bpd). Oil in is scheduled by 4th quarter 2012.
Tritium conversion in tritiated water: study of the involved reactions: a literature survey

International Nuclear Information System (INIS)

Ballereau, P.

1987-10-01

According to ICRP publication 30, hazards due to molecular tritium are not significant in comparison to hazards due to the oxidated form: tritiated water. It is thus important to know the kinetics of tritium/tritiated water conversion to obtain a realistic evaluation of the risks for the environment at level of present facilities and of future nuclear fusion facilities. Laboratory experiments in static contained conditions have shown that tritiated water is produced by two mechanisms: gas phase oxidation, hydrogen isotopic exchange with water. The periods found are relatively long and difficult to specify. In terrestrial atmosphere, the two mechanisms intervening in tritiated water formation are photochemical oxidation and biochemical reactions occurring in soil and in vegetation aerial parts. The corresponding periods are of some years for the first one, of some hours for the second one [fr
A suggestion to assess spilled hydrocarbons as a greenhouse gas source

Energy Technology Data Exchange (ETDEWEB)

McAlexander, Benjamin L., E-mail: bmcalexander@trihydro.com

2014-11-15

Petroleum-contaminated site management typically counts destruction of hydrocarbons by either natural or engineered processes as a beneficial component of remediation. While such oxidation of spilled hydrocarbons is often necessary for achieving risk reduction for nearby human and ecological receptors, site assessments tend to neglect that this also means that the pollutants are converted to greenhouse gases and emitted to the atmosphere. This article presents a suggestion that the current and long term greenhouse gas emissions from spilled hydrocarbons be incorporated to petroleum site assessments. This would provide a more complete picture of pollutant effects that could then be incorporated to remedial objectives. At some sites, this additional information may affect remedy selection. Possible examples include a shift in emphasis to remedial technologies that reduce pollutant greenhouse gas effects (e.g., by conversion of methane to carbon dioxide in the subsurface), and a more holistic context for considering remedial technologies with low emission footprints.
Reaction mechanism for the free-edge oxidation of soot by O 2

KAUST Repository

Raj, Abhijeet

2012-11-01

The reaction pathways for the oxidation by O 2 of polycyclic aromatic hydrocarbons present in soot particles are investigated using density functional theory at B3LYP/6-311++G(d,p) level of theory. For this, pyrene radical (4-pyrenyl) is chosen as the model molecule, as most soot models present in the literature employ the reactions involving the conversion of 4-pyrenyl to 4-phenanthryl by O 2 and OH to account for soot oxidation. Several routes for the formation of CO and CO 2 are proposed. The addition of O 2 on a radical site to form a peroxyl radical is found to be barrierless and exothermic with reaction energy of 188kJ/mol. For the oxidation reaction to proceed further, three pathways are suggested, each of which involve the activation energies of 104, 167 and 115kJ/mol relative to the peroxyl radical. The effect of the presence of H atom on a carbon atom neighboring the radical site on the energetics of carbon oxidation is assessed. Those intermediate species formed during oxidation with seven-membered rings or with a phenolic group are found to be highly stable. The rate constants evaluated using transition state theory in the temperature range of 300-3000K for the reactions involved in the mechanism are provided. © 2012 The Combustion Institute.
Reaction mechanism for the free-edge oxidation of soot by O 2

KAUST Repository

Raj, Abhijeet; da Silva, Gabriel; Chung, Suk-Ho

2012-01-01

The reaction pathways for the oxidation by O 2 of polycyclic aromatic hydrocarbons present in soot particles are investigated using density functional theory at B3LYP/6-311++G(d,p) level of theory. For this, pyrene radical (4-pyrenyl) is chosen as the model molecule, as most soot models present in the literature employ the reactions involving the conversion of 4-pyrenyl to 4-phenanthryl by O 2 and OH to account for soot oxidation. Several routes for the formation of CO and CO 2 are proposed. The addition of O 2 on a radical site to form a peroxyl radical is found to be barrierless and exothermic with reaction energy of 188kJ/mol. For the oxidation reaction to proceed further, three pathways are suggested, each of which involve the activation energies of 104, 167 and 115kJ/mol relative to the peroxyl radical. The effect of the presence of H atom on a carbon atom neighboring the radical site on the energetics of carbon oxidation is assessed. Those intermediate species formed during oxidation with seven-membered rings or with a phenolic group are found to be highly stable. The rate constants evaluated using transition state theory in the temperature range of 300-3000K for the reactions involved in the mechanism are provided. © 2012 The Combustion Institute.
Oxygen-assisted conversion of propane over metal and metal oxide catalysts

Energy Technology Data Exchange (ETDEWEB)

Laate, Leiv

2002-07-01

An experimental set-up has been build and applied in activity/selectivity studies of the oxygen-assisted conversion of propane over metals and metal oxide catalysts. The apparatus has been used in order to achieve an improved understanding of the reactions between alkanes/alkenes and oxygen. Processes that have been studied arc the oxidative dehydrogenation of propane over a VMgO catalyst and the selective combustion of hydrogen in the presence of hydrocarbons over Pt-based catalysts and metal oxide catalysts. From the experiments, the following conclusions are drawn: A study of the oxidative dehydrogenation of propane over a vanadium-magnesium-oxide catalyst confirmed that the main problem with this system is the lack of selectivity due to complete combustion. Selectivity to propene up to about 60% was obtained at 10% conversion at 500{sup o}C, but the selectivity decreased with increasing conversion. No oxygenates were detected, the only by- products were CO and CO{sub 2}. The selectivity to propene is a strong function of the conversion of propane. The reaction rate of propane was found to be 1.0 {+-} 0.1 order in propane and 0.07 {+-} 0.02 order in oxygen. The kinetic results are in agreement with a Mars van Krevelen mechanism with the activation of the hydrocarbons as the slow step. The rate of propene oxidation to CO{sub 2} was studied and found to be significantly higher than that of propane. Another possible process involves the simultaneous equilibrium dehydrogenation of alkanes to alkenes and combustion of the hydrogen formed to shift the equilibrium dehydrogenation reaction further to the product alkenes. A study of the selective combustion of hydrogen in the presence of propane/propene was found to be possible under certain reaction conditions over some metal oxide catalysts. In{sub 2}O{sub 3}/SiO{sub 2}, unsupported Bi{sub 2}O{sub 3} and ZSM-5 show the ability to combust hydrogen in a gas mixture with propane and oxygen with good selectivity. Bi{sub 2
Aromatic hydrocarbons

International Nuclear Information System (INIS)

Roder, M.

1985-01-01

Papers dealing with radiolysis of aromatic hydrocarbons of different composition (from benzene to terphenyls and hydrocarbons with condensed rings) as well as their mixtures (with alkanes, alkenes, other aromatic hydrocarbons) are reviewed. High radiation stability of aromatic hydrocarbons in condensed phases associated with peculiarities of molecular structure of compounds is underlined. Mechanisms of radiolytic processes, vaues of product yields are considered
Analysis of hydrocarbons generated in coalbeds

Science.gov (United States)

Butala, Steven John M.

This dissertation describes kinetic calculations using literature data to predict formation rates and product yields of oil and gas at typical low-temperature conditions in coalbeds. These data indicate that gas formation rates from hydrocarbon thermolysis are too low to have generated commercial quantities of natural gas, assuming bulk first-order kinetics. Acid-mineral-catalyzed cracking, transition-metal-catalyzed hydrogenolysis of liquid hydrocarbons, and catalyzed CO2 hydrogenation form gas at high rates. The gaseous product compositions for these reactions are nearly the same as those for typical natural coalbed gases, while those from thermal and catalytic cracking are more representative of atypical coalbed gases. Three Argonne Premium Coals (Upper-Freeport, Pittsburgh #8 and Lewiston-Stockton) were extracted with benzene in both Soxhlet and elevated pressure extraction (EPE) systems. The extracts were compared on the basis of dry mass yield and hydrocarbon profiles obtained by gas chromatography/mass spectrometry. The dry mass yields for the Upper-Freeport coal gave consistent results by both methods, while the yields from the Pittsburgh #8 and Lewiston-Stockton coals were greater by the EPE method. EPE required ˜90 vol. % less solvent compared to Soxhlet extraction. Single-ion-chromatograms of the Soxhlet extracts all exhibited bimodal distributions, while those of the EPE extracts did not. Hydrocarbons analyzed from Greater Green River Basin samples indicate that the natural oils in the basin originated from the coal seams. Analysis of artificially produced oil indicates that hydrous pyrolysis mimics generation of C15+ n-alkanes, but significant variations were found in the branched alkane, low-molecular-weight n-alkanes, and high-molecular-weight aromatic hydrocarbon distributions.
Spin conversion induced by spin-orbit interaction in positronium collisions

International Nuclear Information System (INIS)

Saito, H; Nakayama, T; Hyodo, T

2009-01-01

The positronium spin conversion reaction induced by spin-orbit interaction is investigated. We obtain the reaction rates during positronium-Xe and positronium-Kr collisions by using the Zeeman mixing of positronium states. At thermal energies corresponding to room temperature, the reaction rate for spin conversion due to spin-orbit interaction is found to be almost twice that for the positronium pick-off reaction. We also study the energy dependence of the reaction rate. The mean energy of positronium is controlled by changing the gas temperature and using positronium in thermal equilibrium. We found that the reaction rate increases with the collision energy.
Chemical storage of renewable electricity in hydrocarbon fuels via H{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Eilers, H.; Iglesias Gonzalez, M.; Schaub, G. [Karlsruhe Institute of Technology (KIT), Karlsruhe (Germany). Engler-Bunte-Institute I

2012-07-01

The increased generation of renewable electricity leads to an increasing demand for storage due to its fluctuating production. Electrical energy can be stored as chemical energy carriers e.g. in form of H{sub 2} that can be further processed to hydrocarbons. Storage in form of hydrocarbons is advantageous compared to H{sub 2} storage since (i) a higher volumetric energy density in the product can be achieved and (ii) the infrastructure for hydrocarbon distribution, storage and utilization already exists. The present contribution introduces the potential of H{sub 2} integration in upgrading/production processes to hydrocarbon fuels, based on stoichiometry and kind of carbon feedstock. Processes include petroleum refining, vegetable oil hydrogenation, production of synfuel from lignocellulosic biomass and substitute natural gas from H{sub 2}/CO{sub 2}. In the case of fossil raw materials, yields per feedstock can be increased and fossil CO{sub 2} emissions decreased since fossil resources for H{sub 2} production can be avoided. In the case of biomass conversion to synfuels, product yields per biomass/hectare can be increased. If CO{sub 2} is hydrogenated to fuels, no gasification step is needed, however lower hydrocarbon product yields per H{sub 2} are achieved since CO{sub 2} has the highest oxygen content. (orig.)

Electrocatalytic process for carbon dioxide conversion

Science.gov (United States)

Masel, Richard I.; Salehi-Khojin, Amin; Kutz, Robert

2017-11-14

An electrocatalytic process for carbon dioxide conversion includes combining a Catalytically Active Element and a Helper Polymer in the presence of carbon dioxide, allowing a reaction to proceed to produce a reaction product, and applying electrical energy to said reaction to achieve electrochemical conversion of said carbon dioxide reactant to said reaction product. The Catalytically Active Element can be a metal in the form of supported or unsupported particles or flakes with an average size between 0.6 nm and 100 nm. The reaction products comprise at least one of CO, HCO.sup.-, H.sub.2CO, (HCO.sub.2).sup.-, H.sub.2CO.sub.2, CH.sub.3OH, CH.sub.4, C.sub.2H.sub.4, CH.sub.3CH.sub.2OH, CH.sub.3COO.sup.-, CH.sub.3COOH, C.sub.2H.sub.6, (COOH).sub.2, (COO.sup.-).sub.2, and CF.sub.3COOH.
Dielectric barrier discharges used for the conversion of greenhouse gases : modeling the plasma chemistry by fluid simulations

NARCIS (Netherlands)

De Bie, C.; Martens, T.; Dijk, van J.; Paulussen, S.; Verheyde, B.; Corthals, S.; Bogaerts, A.

2011-01-01

The conversion of methane to value-added chemicals and fuels is considered to be one of the challenges of the 21st century. In this paper we study, by means of fluid modeling, the conversion of methane to higher hydrocarbons or oxygenates by partial oxidation with CO 2 or O 2 in a dielectric barrier
One-pot aqueous phase catalytic conversion of sorbitol to gasoline over nickel catalyst

International Nuclear Information System (INIS)

Weng, Yujing; Qiu, Songbai; Xu, Ying; Ding, Mingyue; Chen, Lungang; Zhang, Qi; Ma, Longlong; Wang, Tiejun

2015-01-01

Highlights: • Directly production gasoline (C5–C12 alkanes) from biomass-derived sugar alcohol sorbitol. • Temperature of STG (553–593 K) was lower than that of traditional methanol to gasoline (MTG) (623–773 K). • Gasoline yield of 46.9% and C7–C12 hydrocarbons reached up to 45.5% in the gasoline products. - Abstract: The carbon chain extension and hydrodeoxygenation steps play critical roles in the high-energy-density hydrocarbons production. In this paper, a systematic study had been carried out to investigate one-pot aqueous phase catalytic conversion of sorbitol to gasoline (STG) over bifunctional Ni-based catalysts. Characterization technologies of N 2 physisorption, X-ray diffraction (XRD), Scanning electron microscopy (SEM), transmission electron microscopy (TEM) and NH 3 temperature-programmed desorption (NH 3 -TPD) were used to study the textural properties, phase compositions, acid behavior and morphologies of the catalysts. The catalytic performances were tested in a fixed bed reactor. It was found that the physically mixed Ni/HZSM-5 and Ni/silica-gel (mesoporous SG) catalyst realized the carbon chain extension and exhibited excellent performances on hydrodeoxygenation (HDO) reaction (46.9% of gasoline (C5–C12) yield and 45.5% of C7–C12 hydrocarbons in the gasoline products). Especially, the temperature of STG (553–593 K) was lower obviously than that of the traditional methanol to gasoline (MTG) process (623–773 K). It provided a novel transformation of sorbitol to long-chain alkanes by one-pot process over the bifunctional catalyst (Ni@HZSM-5/SG), wherein hydrodeoxygenation, ketonization and aldol condensation steps were integrated
A metal-free electrocatalyst for carbon dioxide reduction to multi-carbon hydrocarbons and oxygenates

Science.gov (United States)

Wu, Jingjie; Ma, Sichao; Sun, Jing; Gold, Jake I.; Tiwary, Chandrasekhar; Kim, Byoungsu; Zhu, Lingyang; Chopra, Nitin; Odeh, Ihab N.; Vajtai, Robert; Yu, Aaron Z.; Luo, Raymond; Lou, Jun; Ding, Guqiao; Kenis, Paul J. A.; Ajayan, Pulickel M.

2016-12-01

Electroreduction of carbon dioxide into higher-energy liquid fuels and chemicals is a promising but challenging renewable energy conversion technology. Among the electrocatalysts screened so far for carbon dioxide reduction, which includes metals, alloys, organometallics, layered materials and carbon nanostructures, only copper exhibits selectivity towards formation of hydrocarbons and multi-carbon oxygenates at fairly high efficiencies, whereas most others favour production of carbon monoxide or formate. Here we report that nanometre-size N-doped graphene quantum dots (NGQDs) catalyse the electrochemical reduction of carbon dioxide into multi-carbon hydrocarbons and oxygenates at high Faradaic efficiencies, high current densities and low overpotentials. The NGQDs show a high total Faradaic efficiency of carbon dioxide reduction of up to 90%, with selectivity for ethylene and ethanol conversions reaching 45%. The C2 and C3 product distribution and production rate for NGQD-catalysed carbon dioxide reduction is comparable to those obtained with copper nanoparticle-based electrocatalysts.
A metal-free electrocatalyst for carbon dioxide reduction to multi-carbon hydrocarbons and oxygenates

Science.gov (United States)

Wu, Jingjie; Ma, Sichao; Sun, Jing; Gold, Jake I.; Tiwary, ChandraSekhar; Kim, Byoungsu; Zhu, Lingyang; Chopra, Nitin; Odeh, Ihab N.; Vajtai, Robert; Yu, Aaron Z.; Luo, Raymond; Lou, Jun; Ding, Guqiao; Kenis, Paul J. A.; Ajayan, Pulickel M.

2016-01-01

Electroreduction of carbon dioxide into higher-energy liquid fuels and chemicals is a promising but challenging renewable energy conversion technology. Among the electrocatalysts screened so far for carbon dioxide reduction, which includes metals, alloys, organometallics, layered materials and carbon nanostructures, only copper exhibits selectivity towards formation of hydrocarbons and multi-carbon oxygenates at fairly high efficiencies, whereas most others favour production of carbon monoxide or formate. Here we report that nanometre-size N-doped graphene quantum dots (NGQDs) catalyse the electrochemical reduction of carbon dioxide into multi-carbon hydrocarbons and oxygenates at high Faradaic efficiencies, high current densities and low overpotentials. The NGQDs show a high total Faradaic efficiency of carbon dioxide reduction of up to 90%, with selectivity for ethylene and ethanol conversions reaching 45%. The C2 and C3 product distribution and production rate for NGQD-catalysed carbon dioxide reduction is comparable to those obtained with copper nanoparticle-based electrocatalysts. PMID:27958290
Conversion of glucose into 5-hydroxymethylfurfural in different solvents and catalysts: Reaction kinetics and mechanism

Directory of Open Access Journals (Sweden)

Cunshan Zhou

2017-06-01

Full Text Available Synthesis of 5-hydroxymethylfurfural (HMF from glucose was done in H2O, dimethylsulfoxide (DMSO and 1-butyl-3-methylimidazolium chloride ([Bmim]Cl catalyzed by metal (III chloride (FeCl3·6H2O, CrCl3·6H2O and AlCl3. The effects of solvent/catalyst system and temperature/time on the performance of the reaction are studied. HMF yield in the different solvents follows a decreasing order as DMSO > [Bmim]Cl > H2O. The highest HMF yield is achieved by CrCl3·6H2O, followed by AlCl3 and then FeCl3·6H2O. An optimal temperature/time is found at 393 K or 403 K and a time between 30 min and 480 min. Under the optimal reaction conditions, HMF yields of 54.43% and 52.86% are obtained in DMSO with CrCl3·6H2O at 403 K and 480 min and AlCl3 at 393 K and 240 min, respectively. The mechanism of the halide chlorides catalyzed glucose conversion reaction is proposed. The kinetic model is established to describe the HMF formation and the experimental data conform to the model.
Extraction of Carbon Dioxide and Hydrogen from Seawater and Hydrocarbon Production Therefrom

Science.gov (United States)

2016-04-05

acidification of seawater by subjecting the seawater to an ion exchange reaction to exchange H.sup. ions for Na.sup. ions. Carbon dioxide may be...extracted from the acidified seawater. Optionally, the ion exchange reaction can be conducted under conditions which produce hydrogen as well as carbon dioxide . The carbon dioxide and hydrogen may be used to produce hydrocarbons.
Laboratory Studies of Hydrocarbon Oxidation Mechanisms

Science.gov (United States)

Orlando, J. J.; Tyndall, G. S.; Wallington, T. J.; Burkholder, J. B.; Bertman, S. B.; Chen, W.

2001-12-01

The oxidation of hydrocarbon species (alkanes, alkenes, halogenated species, and oxygenates of both natural and anthropogenic origin) in the troposphere leads to the generation of numerous potentially harmful secondary pollutants, such as ozone, organic nitrates and acids, and aerosols. These oxidations proceed via the formation of alkoxy radicals, whose complex chemistry controls the ultimate product distributions obtained. Studies of hydrocarbon oxidation mechanisms are ongoing at NCAR and Ford, using environmental chamber / FTIR absorption systems. The focus of these studies is often on the product distributions obtained at low temperature; these studies not only provide data of direct relevance to the free/upper troposphere, but also allow for a more fundamental understanding of the alkoxy radical chemistry (eg., from the determination of the Arrhenius parameters for unimolecular processes, and the quantification of the extent of the involvement of chemical activation in the alkoxy radical chemistry). In this paper, data will be presented on some or all of the following topics: kinetics/mechanisms for the reactions of OH with the unsaturated species MPAN, acrolein, and crotonaldehyde; the mechanism for the oxidation of ethyl chloride and ethyl bromide; and the mechanism for the reaction of OH with acetone and acetaldehyde at low temperature. The relevance of the data to various aspects of tropospheric chemistry will be discussed.
Sodium sulfite pH-buffering effect for improved xylose-phenylalanine conversion to N-(1-deoxy-d-xylulos-1-yl)-phenylalanine during an aqueous Maillard reaction.

Science.gov (United States)

Cui, Heping; Duhoranimana, Emmanuel; Karangwa, Eric; Jia, Chengsheng; Zhang, Xiaoming

2018-04-25

The yield of the Maillard reaction intermediate (MRI), prepared in aqueous medium, is usually unsatisfactory. However, the addition of sodium sulfite could improve the conversion of xylose-phenylalanine (Xyl-Phe) to the MRI (N-(1-deoxy-d-xylulos-1-yl)-phenylalanine) in aqueous medium. Sodium sulfite (Na 2 SO 3 ) showed a significant pH-buffering effect during the Maillard reaction, which accounted for its facilitation of the N-(1-deoxy-d-xylulos-1-yl)-phenylalanine yield. The results revealed that the pH could be maintained at a relatively high level (above 7.0) for an optimized pH-buffering effect when Na 2 SO 3 (4.0%) was added before the reaction of Xyl-Phe. Thus, the conversion of Xyl-Phe to N-(1-deoxy-d-xylulos-1-yl)-phenylalanine increased from 47.23% to 74.86%. Furthermore, the addition moment of Na 2 SO 3 and corresponding solution pH were crucial factors in regulating the pH-buffering effect of Na 2 SO 3 on N-(1-deoxy-d-xylulos-1-yl)-phenylalanine yield. Based on the pH-buffering effect of Na 2 SO 3 and maintaining the optimal pH 7.4 relatively stable, the conversion of Xyl-Phe to N-(1-deoxy-d-xylulos-1-yl)-phenylalanine was successfully improved. Copyright © 2017 Elsevier Ltd. All rights reserved.
Low severity conversion of activated coal. Final report

Energy Technology Data Exchange (ETDEWEB)

Hirschon, A.S.; Ross, D.S.

1990-01-01

The results suggest that coal contains regions with structural components significantly reactive under the hydrothermal environment. Although the specific mechanism for this process remains to be developed, this activity is reminiscent of findings in studies of accelerated maturation of oil shale, where hydrothermal treatment (hydrous pyrolysis) leads to the production of petroleum hydrocarbons. In line with what has been seen in the oil shale work, the pretreatment-generated hydrocarbons and phenols appear to represent a further or more complete maturation of some fraction of the organic material within the coal. These observations could have an impact in two areas. The first is in the area of coal structure, where immature, reactive regions have not been included in the structures considered at present. The second area of interest is the more practical one of conversions to coal liquids and pyrolytic tars. It seems clear that the hydrothermal pretreatment changes the coal in some manner that favorably affects the product quality substantially and, as in the CO/water liquefaction case, favorably affects the yields. The conversions of coals of lower rank, i.e., less mature coals, could particularly benefit in terms of both product quality and product quantity. The second portion of this project also shows important benefits to coal conversion technology. It deals with synthesizing catalysts designed to cleave the weak links in the coal structure and then linking these catalysts with the pretreatment methods in Task 2. The results show that highly dispersed catalysts can effectively be used to increase the yields of soluble material. An important aspect of highly dispersed catalysts are that they can effectively catalyze coal conversion even in poor liquefaction solvents, thus making them very attractive in processes such as coprocessing where inexpensive liquefaction media such as resids are used.
Studies on the production of hydrocarbon mixtures from waste methyl ethyl ketone

International Nuclear Information System (INIS)

Kokitkar, P.B.; Roth, O.B.; Debelak, K.A.

1992-01-01

Large quantities of waste solvents are generated annually around the world in a large number of diverse industries, the paints and plastics industry being the largest consumer. The management of these waste solvents is becoming more and more difficult due to stricter environmental regulations by the EPA. The paint and allied products industry is expected to shift its solvent use from aliphatics and aromatics to oxygenated solvents to meet emissions and disposal standards. Many researchers have studied the dehydration reactions of oxygenated solvents to produce dehydration. However, most researchers have obtained only low molecular weight compounds (C 3 - C 4 hydrocarbons) from C 1 - C 4 alcohols and ketones. The kinetics of this class of reactions are not available in the open literature. The objective of this paper is to investigate the thermodynamic feasibility of this class of reactions and to compare the hydrocarbon products obtained using methylethyl ketone with regular unleaded gasoline
Near wall combustion modeling in spark ignition engines. Part B: Post-flame reactions

International Nuclear Information System (INIS)

Demesoukas, Sokratis; Caillol, Christian; Higelin, Pascal; Boiarciuc, Andrei; Floch, Alain

2015-01-01

Highlights: • Models for the post flame reactions (CO and hydrocarbons) and heat release rate are proposed. • ‘Freezing’ effect of CO kinetics is captured but equilibrium CO concentrations are low. • Reactive–diffusive processes are modeled for hydrocarbons and the last stage of combustion is captured. - Abstract: Reduced fuel consumption, low pollutant emissions and adequate output performance are key features in the contemporary design of spark ignition engines. Zero-dimensional numerical simulation is an attractive alternative to engine experiments for the evaluation of various engine configurations. Both flame front reaction and post-flame processes contribute to the heat release rate. The contribution of this work is to highlight and model the role of post-flame reactions (CO and hydrocarbons) in the heat release rate. The modeling approach to CO kinetics used two reactions considered to be dominant and thus more suitable for the description of CO chemical mechanism. Equilibrium concentrations of all the species involved were calculated by a two-zone thermodynamic model. The computed characteristic time of CO kinetics was found to be of a similar order to the results of complex chemistry simulations. The proposed model captured the ‘freezing’ effect (reaction rate is almost zero) for temperatures lower than 1800 K and followed the trends of the measured values at exhaust. However, a consistent underestimation of CO levels at the exhaust was observed. The impact of the remaining CO on the combustion efficiency is considerable especially for rich mixtures. For a remaining 0.4% CO mass fraction, the impact on combustion inefficiency is 0.1%. Unburnt hydrocarbon, which have not reacted within the flame front before quenching, diffuse in the burnt gas and react. In this work, a global reaction rate models the kinetic behavior of hydrocarbon. The diffusion process was modeled by a relaxation equation applied on the calculated kinetic concentration
Microbial utilization of naturally occurring hydrocarbons at the Guaymas Basin hydrothermal vent site

International Nuclear Information System (INIS)

Bazylinski, D.A.; Wirsen, C.O.; Jannasch, H.W.

1989-01-01

The Guaymas Basin (Gulf of California; depth, 2,000 m) is a site of hydrothermal activity in which petroliferous materials is formed by thermal alteration of deposited planktonic and terrestrial organic matter. We investigated certain components of these naturally occurring hydrocarbons as potential carbon sources for a specific microflora at these deep-sea vent sites. Respiratory conversion of [1- 14 C]hexadecane and [1(4,5,8)- 14 C]naphthalene to 14 CO 2 was observed at 4 degree C and 25 degree C, and some was observed at 55 degree C, but none was observed at 80 degree C. Bacterial isolates were capable of growing on both substrates as the sole carbon source. All isolates were aerobic and mesophilic with respect to growth on hydrocarbons but also grew at low temperatures (4 to 5 degree C). These results correlate well with previous geochemical analyses, indicating microbial hydrocarbon degradation, and show that at least some of the thermally produced hydrocarbons at Guaymas Basin are significant carbon sources to vent microbiota
Conversion of methane to hydrogen by a pulsed plasma reactor

International Nuclear Information System (INIS)

Ghorbanzadeh, A. M.; Matin, N.; Parandvar, M. R.; Rasouli, C.; Mazouchi, A. M.

2003-01-01

A pulsed atmospheric glow discharge, employing corona as a preionization, was used to convert methane to hydrogen and higher hydrocarbons. The experimental results showed that the overall conversion and specific energy, defined as energy needed to dissociate one mole methane, was mainly dependent on E/P, banking capacitance, repetition rate and flow rate. The dependence on E/P, especially, is more pronounced. The minimum specific energy was less than 1 MJ and it is expected that it could be further lowered by choosing higher E/P, lower banking capacitance and introducing an oxidizer to enhance the conversion efficiency
Quantum mechanical study of the proton exchange in the ortho-para H2 conversion reaction at low temperature.

Science.gov (United States)

Honvault, P; Jorfi, M; González-Lezana, T; Faure, A; Pagani, L

2011-11-14

Ortho-para H(2) conversion reactions mediated by the exchange of a H(+) proton have been investigated at very low energy for the first time by means of a time independent quantum mechanical (TIQM) approach. State-to-state probabilities and cross sections for H(+) + H(2) (v = 0, j = 0,1) processes have been calculated for a collision energy, E(c), ranging between 10(-6) eV and 0.1 eV. Differential cross sections (DCSs) for H(+) + H(2) (v = 0, j = 1) → H(+) + H(2) (v' = 0, j' = 0) for very low energies only start to develop a proper global minimum around the sideways scattering direction (θ≈ 90°) at E(c) = 10(-3) eV. Rate coefficients, a crucial information required for astrophysical models, are provided between 10 K and 100 K. The relaxation ortho-para process j = 1 → j' = 0 is found to be more efficient than the j = 0 → j' = 1 conversion at low temperatures, in line with the extremely small ratio between the ortho and para species of molecular hydrogen predicted at the temperature of interstellar cold molecular clouds. The results obtained by means of a statistical quantum mechanical (SQM) model, which has previously proved to provide an adequate description of the dynamics of the title reactions at a higher collision energy regime, have been compared with the TIQM results. A reasonable good agreement has been found with the only exception of the DCSs for the H(+) + H(2) (v = 0, j = 1) → H(+) + H(2) (v' = 0, j' = 0) process at very low energy. SQM cross sections are also slightly below the quantum results. Estimates for the rate coefficients, in good accord with the TIQM values, are a clear improvement with respect to pioneering statistical studies on the reaction.
Kinetic modeling of hydrocracking reaction in a trickle-bed reactor with Pt/Y-zeolite catalysts

Energy Technology Data Exchange (ETDEWEB)

Lee, BalSang; Park, Myung-June; Kim, Young-A; Park, Eun Duck [Ajou University, Suwon (Korea, Republic of); Han, Jeongsik [Agency for Defense Development, Daejeon (Korea, Republic of); Jeong, Kwang-Eun; Kim, Chul-Ung; Jeong, Soon-Yong [Korea Research Institute of Chemical Technology (KRICT), Daejeon (Korea, Republic of)

2014-03-15

A kinetic model is developed to predict the entire distribution of hydrocarbon products for the hydrocracking reaction with Pt/Y-zeolite catalysts in a trickle-bed reactor. Operating conditions, such as temperature, pressure, and wax and H{sub 2} flow rates were varied to evaluate their effects on conversion and distribution, and kinetic parameters were estimated using the experimental data that covers the window of operating conditions. The comparison between experimental data and simulated results corroborated the validity of the developed model, and the quantitative prediction of the reactor performance was clearly demonstrated. To make evident the usefulness of the model, an optimization method, genetic algorithm (GA), was applied, and the optimal condition for the maximum production of C{sub 10}-C{sub 17} was successfully calculated.
Kinetic modeling of hydrocracking reaction in a trickle-bed reactor with Pt/Y-zeolite catalysts

International Nuclear Information System (INIS)

Lee, BalSang; Park, Myung-June; Kim, Young-A; Park, Eun Duck; Han, Jeongsik; Jeong, Kwang-Eun; Kim, Chul-Ung; Jeong, Soon-Yong

2014-01-01

A kinetic model is developed to predict the entire distribution of hydrocarbon products for the hydrocracking reaction with Pt/Y-zeolite catalysts in a trickle-bed reactor. Operating conditions, such as temperature, pressure, and wax and H 2 flow rates were varied to evaluate their effects on conversion and distribution, and kinetic parameters were estimated using the experimental data that covers the window of operating conditions. The comparison between experimental data and simulated results corroborated the validity of the developed model, and the quantitative prediction of the reactor performance was clearly demonstrated. To make evident the usefulness of the model, an optimization method, genetic algorithm (GA), was applied, and the optimal condition for the maximum production of C 10 -C 17 was successfully calculated
External heavy atom effect on intersystem crossing reactions of aromatic hydrocarbons

International Nuclear Information System (INIS)

Wojnarovits, L.; Foeldiak, G.

1988-01-01

The external heavy atom effect by xenon on the S 1 → T n and T 1 → S o transitions of naphthalene and pyrene was investigated in hydrocarbon solvents by fluorescence or absorption spectroscopy. The quencher forms a short-lived encounter complex (that may be called exciplex as well) with the excited molecules in equilibrium process. This exciplex formation in solutions with naphthalene leads to some deviation from the Stern-Volmer type concentration dependence of the quenching. (author)
Chevron's technologies for converting unconventional hydrocarbons into transportation fuels

Energy Technology Data Exchange (ETDEWEB)

Zestar, L.P.; Nordrum, L.J. [Chevron Energy Technology Co., San Roman, CA (United States); Farshid, D.; Reynolds, B.E. [Chevron Global Downstream, San Ramon, CA (United States). Technology Marketing Div.

2009-07-01

Molecules laden with metal, sulphur and nitrogen impurities limit the value of unconventional heavy oils and produce large amounts of low-value byproducts during the processing phase. This paper discussed a vacuum resid slurry hydrocracking (VRSH) process for upgrading vacuum resid from bitumens and extra-heavy oil. The process converted all hydrocarbon materials in the field into high quality, high-value products. The technology used a proprietary ultra-fine slurry catalyst to achieve nearly 100 per cent resid conversion. The majority of the product was converted to distillates. The remaining unconverted oil was retained in a slurry reactor with a highly active and concentrated catalyst in order to enable higher resid conversion. The process generated significant amounts of hydrogen. It was concluded that the process can be operated in high conversion or high throughput modes. 1 tab., 4 figs.
Charge transfer reactions in Xe plasma expansion

International Nuclear Information System (INIS)

Jiao, C. Q.; Garscadden, A.; Ganguly, B. N.

2007-01-01

Charge transfer reactions of fast Xe ions with hydrocarbons including methane (CH 4 ), ethene (C 2 H 4 ), and propane (C 3 H 8 ) are studied by adding these hydrocarbon gases into a cross flowing Xe plasma expansion. Branching ratios and relative reaction rates for the charge transfers of fast Xe + with each of the three hydrocarbon gases are measured under different rf powers of the inductively coupled Xe discharge. For CH 4 /Xe system, we find that fast Xe + reacts readily with CH 4 generating CH 4 + and CH 3 + in a ratio of 1:0.56, with an estimated rate coefficient of (2.3±0.3)x10 -10 cm 3 /s at 75 W rf power which slowly increases to (2.9±0.3)x10 -10 cm 3 /s at 250 W (error bars reflect only the uncertainties due to the unknown extent of the ion recombination that follows the charge transfer reaction). These observed charge transfer reactions are made possible by the kinetically excited Xe ions produced by free expansion of the plasma. For the C 2 H 4 /Xe system product ions C 2 H 4 + and C 2 H 2 + are observed, and for C 3 H 8 /Xe, C 2 H 4 + and C 2 H 5 + and minor product ions including C 2 H 2 + and C 3 H 7 + are observed

Investigation of the combustion kinetics and polycyclic aromatic hydrocarbon emissions from polycaprolactone combustion.

Science.gov (United States)

Chien, Y C; Yang, S H

2013-01-01

Polycaprolactone (PCL) is one of the most attractive biodegradable plastics that has been widely used in medicine and agriculture fields. Because of the large increase in biodegradable plastics usage, the production of waste biodegradable plastics will be increasing dramatically, producing a growing environmental problem. Generally, waste PCL is collected along with municipal solid wastes and then incinerated. This study investigates the combustion kinetics and emission factors of 16 US Environmental Protection Agency (EPA) priority polycyclic aromatic hydrocarbons (PAHs) in the PCL combustion. Experimentally, two reactions are involved in the PCL combustion process, possibly resulting in the emission of carbon dioxide, propanal, protonated caprolactone and very small amounts of PAH produced by incomplete combustion. The intermediate products may continuously be oxidized to form CO2. The emission factors for 16 US EPA priority PAHs are n.d. -2.95 microg/g, which are much lower than those of poly lactic acid and other plastics combustion. The conversion of PCL is 100%. Results from this work suggest that combustion is a good choice for the waste PCL disposal.
Continuous process for converting hydrocarbons, etc

Energy Technology Data Exchange (ETDEWEB)

1934-05-01

A continuous process is disclosed for converting hydrocarbons, liquid, semi-liquid, and solid, of all origins and kinds, into incondensable gases, without carbon deposits, characterized by the fact that an intimate mixture of the material and superheated steam before cracking is passed through a contact mass. The contact mass consists of all metals, metal alloys, and mineral salts which, at the reaction temperature, are fused and do not react with the water vapor or gaseous products.
Analytical solutions for non-linear conversion of a porous solid particle in a gas–I. Isothermal conversion

NARCIS (Netherlands)

Brem, Gerrit; Brouwers, J.J.H.

1990-01-01

Analytical description are presented for non-linear heterogeneous conversion of a porous solid particle reacting with a surrounding gas. Account has been taken of a reaction rate of general order with respect to gas concentration, intrinsic reaction surface area and pore diffusion, which change with
Two-step processing of oil shale to linear hydrocarbons

Energy Technology Data Exchange (ETDEWEB)

Eliseev, O.L.; Ryzhov, A.N.; Latypova, D.Zh.; Lapidus, A.L. [Russian Academy of Sciences, Moscow (Russian Federation). N.D. Zelinsky Institute of Organic Chemistry; Avakyan, T.A. [Gubkin Russian State University of Oil and Gas, Moscow (Russian Federation)

2013-11-01

Thermal and catalytic steam reforming of oil shale mined from Leningrad and Kashpir deposits was studied. Experiments were performed in fixed bed reactor by varying temperature and steam flow rate. Data obtained were approximated by empirical formulas containing some parameters calculated by least-squares method. Thus predicting amount of hydrogen, carbon monoxide and methane in producer gas is possible for given particular kind of oil shale, temperature and steam flow rate. Adding Ni catalyst enriches hydrogen and depletes CO content in effluent gas at low gasification temperatures. Modeling gas simulating steam reforming gases (H{sub 2}, CO, CO{sub 2}, and N{sub 2} mixture) was tested in hydrocarbon synthesis over Co-containing supported catalyst. Selectivity of CO conversion into C{sub 5+} hydrocarbons reaches 84% while selectivity to methane is 7%. Molecular weight distribution of synthesized alkanes obeys Anderson-Schulz-Flory equation and chain growth probability 0.84. (orig.)
WO3 and W Thermal Atomic Layer Etching Using "Conversion-Fluorination" and "Oxidation-Conversion-Fluorination" Mechanisms.

Science.gov (United States)

Johnson, Nicholas R; George, Steven M

2017-10-04

The thermal atomic layer etching (ALE) of WO 3 and W was demonstrated with new "conversion-fluorination" and "oxidation-conversion-fluorination" etching mechanisms. Both of these mechanisms are based on sequential, self-limiting reactions. WO 3 ALE was achieved by a "conversion-fluorination" mechanism using an AB exposure sequence with boron trichloride (BCl 3 ) and hydrogen fluoride (HF). BCl 3 converts the WO 3 surface to a B 2 O 3 layer while forming volatile WO x Cl y products. Subsequently, HF spontaneously etches the B 2 O 3 layer producing volatile BF 3 and H 2 O products. In situ spectroscopic ellipsometry (SE) studies determined that the BCl 3 and HF reactions were self-limiting versus exposure. The WO 3 ALE etch rates increased with temperature from 0.55 Å/cycle at 128 °C to 4.19 Å/cycle at 207 °C. W served as an etch stop because BCl 3 and HF could not etch the underlying W film. W ALE was performed using a three-step "oxidation-conversion-fluorination" mechanism. In this ABC exposure sequence, the W surface is first oxidized to a WO 3 layer using O 2 /O 3 . Subsequently, the WO 3 layer is etched with BCl 3 and HF. SE could simultaneously monitor the W and WO 3 thicknesses and conversion of W to WO 3 . SE measurements showed that the W film thickness decreased linearly with number of ABC reaction cycles. W ALE was shown to be self-limiting with respect to each reaction in the ABC process. The etch rate for W ALE was ∼2.5 Å/cycle at 207 °C. An oxide thickness of ∼20 Å remained after W ALE, but could be removed by sequential BCl 3 and HF exposures without affecting the W layer. These new etching mechanisms will enable the thermal ALE of a variety of additional metal materials including those that have volatile metal fluorides.
Hydrogen--deuterium exchange in saturated hydrocarbons on α-chromia catalyst

International Nuclear Information System (INIS)

Kalman, J.; Guczi, L.

1977-01-01

The kinetics of hydrogen--deuterium exchange in methane, ethane, and propane have been studied with unsupported α-chromia as catalyst in the temperature range of 598 to 688 0 K. The apparent activation energies for methane, ethane, and propane are 88, 130, and 84 kJ mol -1 , respectively, similar to those found on chromia gel. The order of reaction with respect to hydrocarbons and deuterium has been determined as also having the kinetic isotope effect. The main initial products are CH 3 D and CD 4 with methane, C 2 H 4 D 2 and C 2 D 6 with ethane, and C 3 H 7 D and C 3 D 8 with propane. A change in product distribution as a function of temperature, conversion, aging, and oxygen--deuterium treatment has been observed. In agreement with the kinetic data and the effect of oxygen, Cr 3+ has been assumed as the active species of the chromia catalyst, whereas Cr 2+ is an inactive site on the surface. There is no direct proof that chromium ion in a valence state higher than 3+ plays an important role in the exchange reaction. It was established that dual Cr 3+ -- Cr 3+ sites are responsible for the formation of ethane-d 2 . After a long deuterium treatment the number of dual sites is decreased, the effect being revealed in the decreased rate of exchange and the small amount of ethane-d 2 . On the contrary, the formation of methane-d 4 is interpreted by the formation of Cr = C bonds by analogy with homogeneous complexes. In the case of propane, the exchange reaction can be adequately interpreted by a π-allyl mechanism
Control of harmful hydrocarbon species in the exhaust of modern advanced GDI engines

Science.gov (United States)

Hasan, A. O.; Abu-jrai, A.; Turner, D.; Tsolakis, A.; Xu, H. M.; Golunski, S. E.; Herreros, J. M.

2016-03-01

A qualitative and quantitative analysis of toxic but currently non-regulated hydrocarbon compounds ranging from C5-C11, before and after a zoned three-way catalytic converter (TWC) in a modern gasoline direct injection (GDI) engine has been studied using gas chromatography-mass spectrometry (GC-MS). The GDI engine has been operated under conventional and advanced combustion modes, which result in better fuel economy and reduced levels of NOx with respect to standard SI operation. However, these fuel-efficient conditions are more challenging for the operation of a conventional TWC, and could lead to higher level of emissions released to the environment. Lean combustion leads to the reduction in pumping losses, fuel consumption and in-cylinder emission formation rates. However, lean HCCI will lead to high levels of unburnt HCs while the presence of oxygen will lower the TWC efficiency for NOx control. The effect on the catalytic conversion of the hydrocarbon species of the addition of hydrogen upstream the catalyst has been also investigated. The highest hydrocarbon engine-out emissions were produced for HCCI engine operation at low engine load operation. The catalyst was able to remove most of the hydrocarbon species to low levels (below the permissible exposure limits) for standard and most of the advanced combustion modes, except for naphthalene (classified as possibly carcinogenic to humans by the International Agency for Research on Cancer) and methyl-naphthalene (which has the potential to cause lung damage). However, when hydrogen was added upstream of the catalyst, the catalyst conversion efficiency in reducing methyl-naphthalene and naphthalene was increased by approximately 21%. This results in simultaneous fuel economy and environmental benefits from the effective combination of advanced combustion and novel aftertreatment systems.
The study of reactions influencing the biomass steam gasification process

Energy Technology Data Exchange (ETDEWEB)

C. Franco; F. Pinto; I. Gulyurtlu; I. Cabrita [INETI-DEECA, Lisbon (Portugal)

2003-05-01

Steam gasification studies were carried out in an atmospheric fluidised bed. The gasifier was operated over a temperature range of 700 900{sup o}C whilst varying a steam/biomass ratio from 0.4 to 0.85 w/w. Three types of forestry biomass were studied: Pinus pinaster (softwood), Eucalyptus globulus and holm-oak (hardwood). The energy conversion, gas composition, higher heating value and gas yields were determined and correlated with temperature, steam/biomass ratio, and species of biomass used. The results obtained seemed to suggest that the operating conditions were optimised for a gasification temperature around 830{sup o}C and a steam/biomass ratio of 0.6 0.7 w/w, because a gas richer in hydrogen and poorer in hydrocarbons and tars was produced. These conditions also favoured greater energy and carbon conversions, as well the gas yield. The main objective of the present work was to determine what reactions were dominant within the operation limits of experimental parameters studied and what was the effect of biomass type on the gasification process. As biomass wastes usually have a problem of availability because of seasonal variations, this work analysed the possibility of replacing one biomass species by another, without altering the gas quality obtained. 19 refs., 8 figs. 2 tabs.
Performance characterization of CNTs and γ-Al2O3 supported cobalt catalysts in Fischer-Tropsch reaction

International Nuclear Information System (INIS)

Ali, Sardar; Zabidi, Noor Asmawati Mohd; Subbarao, Duvvuri

2014-01-01

Catalysts were prepared via a wet impregnation method. Different physicochemical properties of the samples were revealed by transmission electron microscope (TEM), temperature programmed reduction (H 2 -TPR) and carbon dioxide desorption (CO 2 -desorption). Fischer-Tropsch reaction (FTS) was carried out in a fixed-bed microreactor at 220°C and 1 atm, with H 2 /CO = 2v/v and space velocity, SV of 12L/g.h for 5 h. Various characterization techniques revealed that there was a stronger interaction between Co and Al 2 O 3 support compared to that of CNTs support. CNTs support increased the reducibility and decreased Co particle size. A significant increase in % CO conversion and FTS reaction rate was observed over CNTs support compared to that of Co/Al 2 O 3 . Co/CNTs resulted in higher C 5+ hydrocarbons selectivity compared to that of Co/Al 2 O 3 catalyst. CNTs are a better support for Co compared to Al 2 O 3
Direct formation of gasoline hydrocarbons from cellulose by hydrothermal conversion with in situ hydrogen

International Nuclear Information System (INIS)

Yin, Sudong; Mehrotra, Anil Kumar; Tan, Zhongchao

2012-01-01

A new process based on aqueous-phase dehydration/hydrogenation (APD/H) has been developed to directly produce liquid alkanes (C 7–9 ), which are the main components of fossil gasoline, from cellulose in one single batch reactor without the consumption of external hydrogen (H 2 ). In this new process, part of the cellulose is first converted to in situ H 2 by steam reforming (SR) in the steam gas phase mainly; and, in the liquid water phase, cellulose is converted to an alkane precursor, such as 5-(hydroxymethyl)furfural (HMF). In the final reaction step, in situ H 2 reacts with HMF to form liquid alkanes through APD/H. Accordingly, this new process has been named SR(H 2 )-APD/H. Experimental results show that the volumetric ratio of the reactor headspace to the reactor (H/R) and an initial weakly alkaline condition are the two key parameters for SR(H 2 )-APD/H. With proper H/R ratios (e.g., 0.84) and initial weakly alkaline conditions (e.g., pH = 7.5), liquid alkanes are directly formed from the SR(H 2 )-APD/H of cellulose using in situ H 2 instead of external H 2 . In this study, compared with pyrolysis and hydrothermal liquefaction of cellulose at the same temperatures with same retetion time, SR(H 2 )-APD/H greatly increased the liquid alkane yields, by approximately 700 times and 35 times, respectively. Based on this process, direct formation of fossil gasoline from renewable biomass resources without using external H 2 becomes possible. -- Highlights: ► A process of producing gasoline alkanes from cellulose was proposed and studied. ► Alkane precursors and in situ H 2 were formed simultaneously in a single reactor. ► Alkanes subsequently formed by reactions between in situ H 2 and alkane precursors. ► The yields were 700 and 35 times higher than pyrolysis and hydrothermal conversion.
Quantum chemical investigation of the reaction of O( P2) with certain ...

Indian Academy of Sciences (India)

WINTEC

In the case of methyl radical the minimum energy reaction pathway leads to the products CO + H2 + H. In ... Reactions of atomic oxygen with hydrocarbon radicals play an important role in ..... The reaction between singlet oxygen and propyl ...
Hydrocarbon-degrading sulfate-reducing bacteria in marine hydrocarbon seep sediments

OpenAIRE

Kleindienst, Sara

2012-01-01

Microorganisms are key players in our biosphere because of their ability to degrade various organic compounds including a wide range of hydrocarbons. At marine hydrocarbon seeps, more than 90% of sulfate reduction (SR) is potentially coupled to non-methane hydrocarbon oxidation. Several hydrocarbon-degrading sulfate-reducing bacteria (SRB) were enriched or isolated from marine sediments. However, in situ active SRB remained largely unknown. In the present thesis, the global distribution and a...
Discussion of the Investigation Method on the Reaction Kinetics of Metallurgical Reaction Engineering

Science.gov (United States)

Du, Ruiling; Wu, Keng; Zhang, Jiazhi; Zhao, Yong

Reaction kinetics of metallurgical physical chemistry which was successfully applied in metallurgy (as ferrous metallurgy, non-ferrous metallurgy) became an important theoretical foundation for subject system of traditional metallurgy. Not only the research methods were very perfect, but also the independent structures and systems of it had been formed. One of the important tasks of metallurgical reaction engineering was the simulation of metallurgical process. And then, the mechanism of reaction process and the conversion time points of different control links should be obtained accurately. Therefore, the research methods and results of reaction kinetics in metallurgical physical chemistry were not very suitable for metallurgical reaction engineering. In order to provide the definite conditions of transmission, reaction kinetics parameters and the conversion time points of different control links for solving the transmission and reaction equations in metallurgical reaction engineering, a new method for researching kinetics mechanisms in metallurgical reaction engineering was proposed, which was named stepwise attempt method. Then the comparison of results between the two methods and the further development of stepwise attempt method were discussed in this paper. As a new research method for reaction kinetics in metallurgical reaction engineering, stepwise attempt method could not only satisfy the development of metallurgical reaction engineering, but also provide necessary guarantees for establishing its independent subject system.
Biomass conversion to hydrocarbon fuels using the MixAlco™ process at a pilot-plant scale

International Nuclear Information System (INIS)

Taco Vasquez, Sebastian; Dunkleman, John; Chaudhuri, Swades K.; Bond, Austin; Holtzapple, Mark T.

2014-01-01

Texas A and M University has built a MixAlco™ pilot plant that converts biomass to hydrocarbons (i.e., jet fuel, gasoline) using the following steps: fermentation, descumming, dewatering, thermal ketonization, distillation, hydrogenation, and oligomerization. This study describes the pilot plant and reports results from an 11-month production campaign. The focus was to produce sufficient jet fuel to be tested by the U.S. military. Because the scale was relatively small, energy-saving features were not included in the pilot plant. Further, the equipment was operated in a manner to maximize productivity even if yields were low. During the production campaign, a total of 6.015 Mg of shredded paper and 120 kg of chicken manure (dry basis) were fermented to produce 126.5 m 3 of fermentation broth with an average concentration of 12.5 kg m −3 . A total of 1582 kg of carboxylate salts were converted to 587 L of raw ketones, which were distilled and hydrogenated to 470 L of mixed alcohols ranging from C3 to C12. These alcohols, plus 300 L of alcohols made by an industrial partner (Terrabon, Inc.) were shipped to an independent contractor (General Electric) and transformed to jet fuel (∼100 L) and gasoline (∼100 L) byproduct. - Highlights: • We produce hydrocarbons from paper and chicken manure in a pilot-scale production using the MixAlco™ process. • About 100 L of jet fuel were produced for military testing. • High production rates and good product quality were preferred rather than high yields or energy efficiency. • The MixAlco™ process converted successfully lignocellulosic biomass to hydrocarbons and viable for commercial-scale production
Abstracts of the first ORNL workshop on polycyclic aromatic hydrocarbons: characterization and measurement with a view toward personnel protection. [PAH from coal conversion

Energy Technology Data Exchange (ETDEWEB)

Gammage, R.B. (comp.)

1976-11-01

This report contains the abstracts of papers presented at a workshop on polycyclic aromatic hydrocarbons (PAH) such as those produced by coal conversion technologies. Their often carcinogenic nature imposes the obligation of providing adequate protection and measurement devices for workers and for the general public. The primary questions are as follows: What should be measured. Where and how should it be measured. What are the maximum permissible concentrations. This workshop and future workshops are intended to bring these problems into better focus and to help establish a consensus on what needs to be done in order to provide a dosimetry effort that will ensure the adequate protection of personnel. There were 32 attendees of this one-day meeting. The papers and discussions included current industrial hygiene practices, the development of government agency guidelines for worker protection, and a wide range of analytical techniques for PAH detection, some of which are still in the research stage and are unproven. The workshop was held at ORNL on February 26, 1976.
Fast co-pyrolysis of waste newspaper with high-density polyethylene for high yields of alcohols and hydrocarbons.

Science.gov (United States)

Chen, Weimin; Shi, Shukai; Chen, Minzhi; Zhou, Xiaoyan

2017-09-01

Waste newspaper (WP) was first co-pyrolyzed with high-density polyethylene (HDPE) using pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) to enhance the yields of alcohols and hydrocarbons. The effects of WP: HDPE feed ratio (100:0, 75:25, 50:50, 25:75, 0:100) and temperature (500-800°C) on products distribution were investigated and the interaction mechanism during co-pyrolysis was also proposed. Maximum yields of alcohols and hydrocarbons reached 85.88% (feed ratio 50:50wt.%, 600°C). Hydrogen supplements and deoxidation by HDPE and subsequently fragments recombination result in the conversion of aldehydes and ketones into branched hydrocarbons. Radicals from WP degradation favor the secondary crack for HDPE products resulting in the formation of linear hydrocarbons with low carbon number. Hydrocarbons with activated radical site from HDPE degradation were interacted with hydroxyl from WP degradation promoting the formation of linear long chain alcohols. Moreover, co-pyrolysis significantly enhanced condensable oil qualities, which were close to commercial diesel No. 0. Copyright © 2017 Elsevier Ltd. All rights reserved.
Detailed modeling of hydrocarbon nanoparticle nucleation in acetylene discharges

International Nuclear Information System (INIS)

Bleecker, Kathleen de; Bogaerts, Annemie; Goedheer, Wim

2006-01-01

The initial stage of nanoparticle formation and growth in radiofrequency acetylene (C 2 H 2 ) plasmas is investigated by means of a self-consistent one-dimensional fluid model. A detailed chemical kinetic scheme, containing electron impact, ion-neutral, and neutral-neutral reactions, has been developed in order to predict the underlying dust growth mechanisms and the most important dust precursors. The model considers 41 different species (neutrals, radicals, ions, and electrons) describing hydrocarbons (C n H m ) containing up to 12 carbon atoms. Possible routes for particle growth are discussed. Both positive and negative ion reaction pathways are considered, as consecutive anion- and cation-molecule reactions seem to lead to a fast build up of the carbon skeleton
Photocure Reactions of Photoreactive Prepolymers with Cinnamate Groups

International Nuclear Information System (INIS)

Kim, Whan Gun

2011-01-01

The photoreactive prepolymers with multifunctional cinnamate and bisphenol A type cinnamate groups that could perform photodimerization without photoinitiators were synthesized by the reaction of t-cinnamic acids (CAs) and epoxy resins. Their photocure reaction rates and the extent of reaction conversion were measured with Fourier transform infrared spectroscopy, and these increased with the intensity of UV irradiation. The experimental data of these reaction rates showed the characteristics of nth-order kinetics reaction, and all kinetic constants of each photoreactive polymer with this equation were summarized. Although the GTR-1800-HCA and KWG1-EP-HCA with hydroxyl group substituted cinnamate showed lower reaction conversion rates and rate constant than GTR-1800-CA and KWG1-EP-CA with an unsubstituted cinnamate group, GTR-1800-MCAand KWG1-EP-MCA with methoxy group substituted cinnamate showed similar and higher reaction conversion rates than the former, respectively. These results were explained in terms of segmental mobility for photopolymerization by molecular interactions
Catalysts for the production of hydrocarbons from carbon monoxide and water

Science.gov (United States)

Sapienza, R.S.; Slegeir, W.A.; Goldberg, R.I.

1985-11-06

A method of converting low H/sub 2//CO ratio syngas to carbonaceous products comprising reacting the syngas with water or steam at 200 to 350/sup 0/C in the presence of a metal catalyst supported on zinc oxide. Hydrocarbons are produced with a catalyst selected from cobalt, nickel or ruthenium and alcohols are produced with a catalyst selected from palladium, platinum, ruthenium or copper on the zinc oxide support. The ratio of the reactants are such that for alcohols and saturated hydrocarbons: (2n + 1) greater than or equal to x greater than or equal to O and for olefinic hydrocarbons: 2n greater than or equal to x greater than or equal to O where n is the number of carbon atoms in the product and x is the molar amount of water in the reaction mixture.
Kinetic Studies of Oxidative Coupling of Methane Reaction on Model Catalysts

KAUST Repository

Khan, Abdulaziz M.

2016-04-26

With the increasing production of natural gas as a result of the advancement in the technology, methane conversion to more valuable products has become a must. One of the most attractive processes which allow the utilization of the world’s most abundant hydrocarbon is the oxidative coupling. The main advantage of this process is the ability of converting methane into higher paraffins and olefins (primarily C2) in a direct way using a single reactor. Nevertheless, low C2+ yields have prevented the process to be commercialized despite the fact that great number of attempts to prepare catalysts were conducted so that it can be economically viable. Due to these limitations, understanding the mechanism and kinetics of the reaction can be utilized in improving the catalysts’ performance. The reaction involves the formation of methyl radicals that undergo gas-phase radical reactions. CH4 activation is believed to be done the surface oxygen species. However, recent studies showed that, in addition to the surface oxygen mediated pathway, an OH radical mediated pathway have a large contribution on the CH4 activation. The experiments of Li/MgO, Sr/La2O3 and NaWO4/SiO2 catalysts revealed variation of behavior in activity and selectivity. In addition, water effect analysis showed that Li/MgO deactivate at the presence of water due to sintering phenomena and the loss of active sites. On the other hand, negative effect on the C2 yield and CH4 conversion rate was observed with Sr/La2O3 with increasing the water partial pressure. Na2WO4/SiO2 showed a positive behavior with water in terms of CH4 conversion and C2 yield. In addition, the increment in CH4 conversion rate was found to be proportional with PO2 ¼ PH2O ½ which is consistent with the formation of OH radicals and the OH-mediated pathway. Experiments of using ring-dye laser, which is used to detect OH in combustion experiments, were tried in order to detect OH radicals in the gas-phase of the catalyst. Nevertheless

Hydrogenating gaseous hydrocarbons

Energy Technology Data Exchange (ETDEWEB)

Nicolardot, P L.F.

1930-08-06

Gaseous hydrocarbons obtained by the destructive distillation of carbonaceous materials are simultaneously desulfurized and hydrogenated by passing them at 350 to 500/sup 0/C, mixed with carbon monoxide and water vapor over lime mixed with metallic oxides present in sufficient amount to absorb the carbon dioxide as it is formed. Oxides of iron, copper, silver, cobalt, and metals of the rare earths may be used and are mixed with the lime to form a filling material of small pieces filling the reaction vessel which may have walls metallized with copper and zinc dust. The products are condensed and fixed with absorbents, e.g. oils, activated carbon, silica gels. The metallic masses may be regenerated by a hot air stream and by heating in inert gases.
Analysis of petroleum hydrocarbons in soil from view of bioremediation process

International Nuclear Information System (INIS)

Mracnova, R.; Sojak, L.; Kubinec, R.; Kraus, A.; Eszenyiova, A.; Ostrovsky, I.

2002-01-01

The pollution of the environment by petroleum hydrocarbons is the most often pollution of them all. Nevertheless, hydrocarbons present in environment can be not only of petroleum or anthropogenic origin, but of biogenic as well. Typically the hydrocarbons are presented in the environment as very complex mixtures of individual compounds with very different chemical structure, wide range of the boiling points (∼800 0 C) as well as with the wide range of the number of carbon atoms. Immediately they are spread in any environmental matrix the complex physical, chemical and biochemical reactions start. A lot of methods have been developed and new are permanently in progress for the monitoring and control of petroleum hydrocarbons contamination and/or soils bioremediation. Generally, all methods by whose the hydrocarbons contaminants are determined in GC-FID system do not satisfied recommendations for enough accurate and precise results. Hyphenation of capillary gas chromatography and mass selective detector operated in the selective ion monitoring mode essentially allows detailed specification of non-polar extractable hydrocarbons. Isoprenoid alkanes, alkylhomologues of aromatic hydrocarbons and polycyclic alkanes hopanes-like were investigated as markers for recognition of petroleum and biogenic contamination. C 30 17α(H)21β(H)-hopane (C 30 -hopane) seems to be a suitable marker to identify hydrocarbons origin, to determine composting rates for nonpolar extractable compounds and to calculate real content of non-polar extractable compounds in final composting status on the assumption that the contamination is of mineral oil type. This is the survey into the results obtained in this field published in the literature as well as reached in our laboratory. (author)
Accelerated methanogenesis from aliphatic and aromatic hydrocarbons under iron- and sulfate-reducing conditions.

Science.gov (United States)

Siegert, Michael; Cichocka, Danuta; Herrmann, Steffi; Gründger, Friederike; Feisthauer, Stefan; Richnow, Hans-Hermann; Springael, Dirk; Krüger, Martin

2011-02-01

The impact of four electron acceptors on hydrocarbon-induced methanogenesis was studied. Methanogenesis from residual hydrocarbons may enhance the exploitation of oil reservoirs and may improve bioremediation. The conditions to drive the rate-limiting first hydrocarbon-oxidizing steps for the conversion of hydrocarbons into methanogenic substrates are crucial. Thus, the electron acceptors ferrihydrite, manganese dioxide, nitrate or sulfate were added to sediment microcosms acquired from two brackish water locations. Hexadecane, ethylbenzene or 1-(13)C-naphthalene were used as model hydrocarbons. Methane was released most rapidly from incubations amended with ferrihydrite and hexadecane. Ferrihydrite enhanced only hexadecane-dependent methanogenesis. The rates of methanogenesis were negatively affected by sulfate and nitrate at concentrations of more than 5 and 1 mM, respectively. Metal-reducing Geobacteraceae and potential sulfate reducers as well as Methanosarcina were present in situ and in vitro. Ferrihydrite addition triggered the growth of Methanosarcina-related methanogens. Additionally, methane was removed concomitantly by anaerobic methanotrophy. ANME-1 and -2 methyl coenzyme M reductase genes were detected, indicating anaerobic methanotrophy as an accompanying process [Correction added 16 December after online publication: 'methyl coenzyme A' changed to 'methyl coenzyme M' in this sentence]. The experiments presented here demonstrate the feasibility of enhancing methanogenic alkane degradation by ferrihydrite or sulfate addition in different geological settings. © 2010 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.
The bacterial catabolism of polycyclic aromatic hydrocarbons: Characterization of three hydratase-aldolase-catalyzed reactions

Directory of Open Access Journals (Sweden)

Jake A. LeVieux

2016-12-01

Full Text Available Polycyclic aromatic hydrocarbons (PAHs are highly toxic, pervasive environmental pollutants with mutagenic, teratogenic, and carcinogenic properties. There is interest in exploiting the nutritional capabilities of microbes to remove PAHs from various environments including those impacted by improper disposal or spills. Although there is a considerable body of literature on PAH degradation, the substrates and products for many of the enzymes have never been identified and many proposed activities have never been confirmed. This is particularly true for high molecular weight PAHs (e.g., phenanthrene, fluoranthene, and pyrene. As a result, pathways for the degradation of these compounds are proposed to follow one elucidated for naphthalene with limited experimental verification. In this pathway, ring fission produces a species that can undergo a non-enzymatic cyclization reaction. An isomerase opens the ring and catalyzes a cis to trans double bond isomerization. The resulting product is the substrate for a hydratase-aldolase, which catalyzes the addition of water to the double bond of an α,β-unsaturated ketone, followed by a retro-aldol cleavage. Initial kinetic and mechanistic studies of the hydratase-aldolase in the naphthalene pathway (designated NahE and two hydratase-aldolases in the phenanthrene pathway (PhdG and PhdJ have been completed. Crystallographic work on two of the enzymes (NahE and PhdJ provides a rudimentary picture of the mechanism and a platform for future work to identify the structural basis for catalysis and the individual specificities of these hydratase-aldolases.
Catalytic Conversion of Biomass to Fuels and Chemicals Using Ionic Liquids

Energy Technology Data Exchange (ETDEWEB)

Liu, Wei; Zheng, Richard; Brown, Heather; Li, Joanne; Holladay, John; Cooper, Alan; Rao, Tony

2012-04-13

This project provides critical innovations and fundamental understandings that enable development of an economically-viable process for catalytic conversion of biomass (sugar) to 5-hydroxymethylfurfural (HMF). A low-cost ionic liquid (Cyphos 106) is discovered for fast conversion of fructose into HMF under moderate reaction conditions without any catalyst. HMF yield from fructose is almost 100% on the carbon molar basis. Adsorbent materials and adsorption process are invented and demonstrated for separation of 99% pure HMF product and recovery of the ionic liquid from the reaction mixtures. The adsorbent material appears very stable in repeated adsorption/regeneration cycles. Novel membrane-coated adsorbent particles are made and demonstrated to achieve excellent adsorption separation performances at low pressure drops. This is very important for a practical adsorption process because ionic liquids are known of high viscosity. Nearly 100% conversion (or dissolution) of cellulose in the catalytic ionic liquid into small molecules was observed. It is promising to produce HMF, sugars and other fermentable species directly from cellulose feedstock. However, several gaps were identified and could not be resolved in this project. Reaction and separation tests at larger scales are needed to minimize impacts of incidental errors on the mass balance and to show 99.9% ionic liquid recovery. The cellulose reaction tests were troubled with poor reproducibility. Further studies on cellulose conversion in ionic liquids under better controlled conditions are necessary to delineate reaction products, dissolution kinetics, effects of mass and heat transfer in the reactor on conversion, and separation of final reaction mixtures.
Pocess for the conversion of coal into benzine

Energy Technology Data Exchange (ETDEWEB)

Jacob, S M; Kuo, J C.W.; Wise, J J; Garwood, W E

1976-10-21

The effective conversion of coal into liquid hydrocarbon benzine with a high octane number is described in the claimed method for coal enrichment. The coal is converted with O/sub 2/ and H/sub 2/O at about 788 to 982/sup 0/C giving a synthesis product (containing CO, CO/sub 2/, H/sub 2/ and CH/sub 4/). The conversion of the carbon oxides and hydrogen to a product containing H/sub 2/O, C/sup -//sub 4/gas and C/sup +//sub 5/ aromatic benzine is catalyzed with a catalyst consisting of a crystalline alumino silicate zeolite with a SiO/sub 2//AlO/sub 2/ ratio of at least 12 and a forced index of 1 to 12. The C/sup -//sub 4/gas is separated into a C/sup -//sub 2/residual gas (CH/sub 4/, C/sub 2/H/sub 6/, C/sub 2/H/sub 4/) and alkylation material (saturated and unsaturated C/sub 3/, C/sub 4/ hydrocarbons), the latter alkylated with strong acid at about 232/sup 0/C, 35.2Kg/cm/sup 2/ pressure, the C/sub 7//C/sub 8/ product is mixed with the aromatic benzine, the C/sup -//sub 2/residual gas steam reformed to an auxiliary synthesis gas and converted into a synthetic natural gas by methanation catalysts.
Fischer-Tropsch diesel production over calcium-promoted Co/alumina catalyst: Effect of reaction conditions

Energy Technology Data Exchange (ETDEWEB)

A.R. de la Osa; A. De Lucas; A. Romero; J.L. Valverde; P. Sanchez [University of Castilla-La Mancha, Ciudad Real (Spain). Chemical Engineering Department

2011-05-15

The effects of reaction conditions on the Fischer-Tropsch activity and product distribution of an alkali-earth metal promoted cobalt based catalyst were studied. The influence of the promoter on the reducibility and cobalt particle size was studied by different techniques, including N{sub 2} adsorption, X-ray diffraction, temperature-programmed reduction, temperature-programmed desorption and acid-base titrations. Experiments were carried out on a bench-scale fixed bed reactor and catalysts were prepared by incipient wetness impregnation. It was observed that addition of a small amount of calcium oxide as a promoter (0.6 wt.%) improved the cobalt oxide reducibility and reduced the formation of cobalt-aluminate species. A positive correlation between basicity and particle size was observed. In terms of FTS results, CO conversion and C{sub 5}{sup +} selectivity were found to be enhanced by the addition of this promoter. It was important to note that the addition of calcium shifted the distribution to mainly C{sub 16}-C{sub 18} hydrocarbons fraction, which could be greatly considered for a diesel formulation. Furthermore, the variation of the reaction conditions seemed to influence product distribution in a lesser extent than unpromoted catalyst. Also, a displacement of hydrocarbon distribution to higher molecular weight with decreasing space velocity and temperature was observed. Moreover, the addition of calcium to the cobalt based catalyst was found to greatly maintain selectivity to C{sub 5}{sup +} for a wide range of H{sub 2}/CO molar ratios. 60 refs., 10 figs., 5 tabs.
Process Design and Economics for the Conversion of Lignocellulosic Biomass to Hydrocarbon Fuels: Thermochemical Research Pathways with In Situ and Ex Situ Upgrading of Fast Pyrolysis Vapors

Energy Technology Data Exchange (ETDEWEB)

Dutta, Abhijit [National Renewable Energy Lab. (NREL), Golden, CO (United States); Sahir, A. H. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Tan, Eric [National Renewable Energy Lab. (NREL), Golden, CO (United States); Humbird, David [DWH Process Consulting, Denver, CO (United States); Snowden-Swan, Lesley J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Meyer, Pimphan A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Ross, Jeff [Harris Group, Inc., Seattle, WA (United States); Sexton, Danielle [Harris Group, Inc., Seattle, WA (United States); Yap, Raymond [Harris Group, Inc., Seattle, WA (United States); Lukas, John [Harris Group, Inc., Seattle, WA (United States)

2015-03-01

This report was developed as part of the U.S. Department of Energy’s Bioenergy Technologies Office’s efforts to enable the development of technologies for the production of infrastructure-compatible, cost-competitive liquid hydrocarbon fuels from biomass. Specifically, this report details two conceptual designs based on projected product yields and quality improvements via catalyst development and process integration. It is expected that these research improvements will be made within the 2022 timeframe. The two conversion pathways detailed are (1) in situ and (2) ex situ upgrading of vapors produced from the fast pyrolysis of biomass. While the base case conceptual designs and underlying assumptions outline performance metrics for feasibility, it should be noted that these are only two of many other possibilities in this area of research. Other promising process design options emerging from the research will be considered for future techno-economic analysis. Both the in situ and ex situ conceptual designs, using the underlying assumptions, project MFSPs of approximately $3.5/gallon gasoline equivalent (GGE). The performance assumptions for the ex situ process were more aggressive with higher distillate (diesel-range) products. This was based on an assumption that more favorable reaction chemistry (such as coupling) can be made possible in a separate reactor where, unlike in an in situ upgrading reactor, one does not have to deal with catalyst mixing with biomass char and ash, which pose challenges to catalyst performance and maintenance. Natural gas was used for hydrogen production, but only when off gases from the process was not sufficient to meet the needs; natural gas consumption is insignificant in both the in situ and ex situ base cases. Heat produced from the burning of char, coke, and off-gases allows for the production of surplus electricity which is sold to the grid allowing a reduction of approximately 5¢/GGE in the MFSP.
Halogenated hydrocarbons - an environmental problem

Energy Technology Data Exchange (ETDEWEB)

Schoeler, H F; Thofern, E

1984-01-01

The paper provides a survey of the incidence of highly volatile halogenated hydrocarbons in ground, surface and drinking water as well as in the snows of Western Germany. Almost the entire production of chlorinated solvents is released into the environment. The absorption media are mostly soil, water and atmosphere. Whereas in the atmosphere elimination reactions take place, solvents that have passed the soil get into the ground water owing to their persistence and can cause considerable pollutions of drinking water. Moreover haloforms may occur in drinking water, which are produced during chlorine disinfection of pre-treated water.
Study of higher hydrocarbon production during ethylacetylene pyrolysis using laser-generated vacuum-ultraviolet photoionization detection

Energy Technology Data Exchange (ETDEWEB)

Boyle, J.; Pfefferle, L. (Yale Univ., New Haven, CT (USA))

1990-04-19

Higher hydrocarbon formation during the pyrolysis of ethylacetylene in a microjet reactor was studied by vacuum-ultraviolet photoionization time-of-flight mass spectrometry. At the wavelength employed, this ionization technique allows for the simultaneous detection of both stable and intermediate polyatomic species with ionization potentials below 10.49 eV, including most hydrocarbons with two or more carbon atoms. Minimal fragmentation simplifies the determination of parent species and allows identification of probable reaction pathways involving hydrocarbon radicals as well as stable species. The pyrolysis of ethylacetylene was carried out in the fast-flow microjet reactor (residence times 1-2 ms) at temperatures from 300 to 1,600 K.
[Hydroxylamine conversion by anammox enrichment].

Science.gov (United States)

Hu, Anhui; Zheng, Ping; Lu, Huifeng; Ding, Shuang; Wang, Caihua

2010-04-01

Hydroxylamine is an important intermediate product of anammox. This study was focused on the characteristics of hydroxylamine and nitrite conversions by anammox enrichment. The changes of nitrogenous substrates and related products with time were measured using batch tests with anammox enrichment as inoculum. Since hydroxylamine didn't react with nitrite in uninoculated control culture, these two compounds were chemically stable. Both of them decreased with time in anammox enrichment inoculated cultures, in which ammonia as intermediate product would be produced and converted with the maximum concentration being 0.338 mg/L. The total nitrogen concentration decreased from 4.694 mmol/L to 0.812 mmol/L with conversion rate 82.7% in the end. When hydroxylamine and nitrite concentrations were about 2.5 mmol/L respectively, the maximum specific sludge conversion rates of hydroxylamine was 0.535 mmol/(gVSS.h), which was 1.81 times bigger than that of ammonia in ammonia reaction system; the maximum specific sludge rate of total nitrogen was slightly higher than that in ammonia reaction system. When hydroxylamine concentration increased to 5.0 mmol/L, the hydroxylamine and nitrite conversion rates promoted by 26.7% and 120.7% respectively; and the maximum ammonia accumulated was 1.810 mmol/L. When nitrite concentration increased to 5.0 mmol/L, the hydroxylamine and nitrite conversion rates promoted by 6.9% and 9.0% respectively; and the maximum ammonia accumulated was 0.795 mmol/L. Anammox enrichment was capable of converting hydroxylamine and nitrite simultaneously and had the higher conversion rate of hydroxylamine than ammonia conversion rate. Hydroxylamine and nitrite conversion rates were less affected by increase in nitrite concentration, but more significantly influenced by increase in hydroxylamine. The maximum ammonia concentration accumulated would rise as the result of increasing both hydroxylamine and nitrite. The result of experiment was consistent with pathway
Community Structure in Methanogenic Enrichments Provides Insight into Syntrophic Interactions in Hydrocarbon-Impacted Environments

DEFF Research Database (Denmark)

Fowler, Jane; Toth, Courtney R. A.; Gieg, Lisa M.

2016-01-01

, but such information has important implications for bioremediation and microbial enhanced energy recovery technologies. Many factors such as changing environmental conditions or substrate variations can influence the composition and biodegradation capabilities of syntrophic microbial communities in hydrocarbon......The methanogenic biodegradation of crude oil involves the conversion of hydrocarbons to methanogenic substrates by syntrophic bacteria and subsequent methane production by methanogens. Assessing the metabolic roles played by various microbial species in syntrophic communities remains a challenge......-impacted environments. In this study, a methanogenic crude oil-degrading enrichment culture was successively transferred onto the single long chain fatty acids palmitate or stearate followed by their parent alkanes, hexadecane or octadecane, respectively, in order to assess the impact of different substrates...
Overview of biomass conversion technologies

International Nuclear Information System (INIS)

Noor, S.; Latif, A.; Jan, M.

2011-01-01

A large part of the biomass is used for non-commercial purposes and mostly for cooking and heating, but the use is not sustainable, because it destroys soil-nutrients, causes indoor and outdoor pollution, adds to greenhouse gases, and results in health problems. Commercial use of biomass includes household fuelwood in industrialized countries and bio-char (charcoal) and firewood in urban and industrial areas in developing countries. The most efficient way of biomass utilization is through gasification, in which the gas produced by biomass gasification can either be used to generate power in an ordinary steam-cycle or be converted into motor fuel. In the latter case, there are two alternatives, namely, the synthesis of methanol and methanol-based motor fuels, or Fischer-Tropsch hydrocarbon synthesis. This paper deals with the technological overview of the state-of-the-art key biomass-conversion technologies that can play an important role in the future. The conversion routes for production of Heat, power and transportation fuel have been summarized in this paper, viz. combustion, gasification, pyrolysis, digestion, fermentation and extraction. (author)
Formation of polycyclic aromatic hydrocarbons in circumstellar envelopes

International Nuclear Information System (INIS)

Frenklach, M.; Feigelson, E.D.

1989-01-01

Production of polycyclic aromatic hydrocarbons in carbon-rich circumstellar envelopes was investigated using a kinetic approach. A detailed chemical reaction mechanism of gas-phase PAH formation and growth, containing approximately 100 reactions of 40 species, was numerically solved under the physical conditions expected in cool stellar winds. The chemistry is based on studies of soot production in hydrocarbon pyrolysis and combustion. Several first-ring and second-ring cyclization processes were considered. A linear lumping algorithm was used to describe PAH growth beyond the second aromatic ring. PAH production using this mechanism was examined with respect to a grid of idealized constant velocity stellar winds as well as several published astrophysical models. The basic result is that the onset of PAH production in the interstellar envelopes is predicted to occur within the temperature interval of 1100 to 900 K. The absolute amounts of the PAHs formed, however, are very sensitive to a number of parameters, both chemical and astrophysical, whose values are not accurately known. Astrophysically meaningful quantities of PAHs require particularly dense and slow stellar winds and high initial acetylene abundance. It is suggested that most of the PAHs may be produced in a relatively small fraction of carbon-rich red giants. 87 refs
Preliminary experiments aiming the production of `vegetable petroleum` by the catalytic conversion of `babacu` and castor oils; Experimentos preliminares visando a producao de petroleo vegetal, pela conversao catalitica de oleos de mamona e babassu

Energy Technology Data Exchange (ETDEWEB)

Weyne, Gastao Rubio de Sa [Sao Paulo Univ., SP (Brazil). Escola Politecnica. Dept. de Engenharia Quimica

1989-09-01

The catalytic conversion of vegetable oils produces hydrocarbons and despite the industrial production of that raw materials being expensive and even insufficient for a substitution program, Brazil has conditions to increase it and to get lower cost because the very much favourable conditions of soil to plant oleaginous seeds. In this work are presented the preliminary experimentalresults of this catalytic conversion in laboratory scale carried out in the Department of Chemical Engineering at Polytechnical School of Sao Paulo University, using babassu and castor oils and several catalysts at bentonits, zeolites and sodium chloride. The `vegetable petroleum` produced was quantitatively analysed, being determined the paraffin, olefinic, naphtene and aromatic hydrocarbons. ASTM distillation was carried out. At the temperature of 300 deg C and atmospheric pression, the batter catalyst was the sodium chloride, giving a yield larges than 80% volume. It shows that, in spite of producing hydrocarbons at higher costs than the ones obtained from petroleum, it is necessary to enlarge the studies for the conversion to hydrocarbons as one of the answers to the Brazilian energetic problem. (author) 13 refs., 4 tabs.
Efficient electrochemical CO2 conversion powered by renewable energy.

Science.gov (United States)

Kauffman, Douglas R; Thakkar, Jay; Siva, Rajan; Matranga, Christopher; Ohodnicki, Paul R; Zeng, Chenjie; Jin, Rongchao

2015-07-22

The catalytic conversion of CO2 into industrially relevant chemicals is one strategy for mitigating greenhouse gas emissions. Along these lines, electrochemical CO2 conversion technologies are attractive because they can operate with high reaction rates at ambient conditions. However, electrochemical systems require electricity, and CO2 conversion processes must integrate with carbon-free, renewable-energy sources to be viable on larger scales. We utilize Au25 nanoclusters as renewably powered CO2 conversion electrocatalysts with CO2 → CO reaction rates between 400 and 800 L of CO2 per gram of catalytic metal per hour and product selectivities between 80 and 95%. These performance metrics correspond to conversion rates approaching 0.8-1.6 kg of CO2 per gram of catalytic metal per hour. We also present data showing CO2 conversion rates and product selectivity strongly depend on catalyst loading. Optimized systems demonstrate stable operation and reaction turnover numbers (TONs) approaching 6 × 10(6) molCO2 molcatalyst(-1) during a multiday (36 h total hours) CO2 electrolysis experiment containing multiple start/stop cycles. TONs between 1 × 10(6) and 4 × 10(6) molCO2 molcatalyst(-1) were obtained when our system was powered by consumer-grade renewable-energy sources. Daytime photovoltaic-powered CO2 conversion was demonstrated for 12 h and we mimicked low-light or nighttime operation for 24 h with a solar-rechargeable battery. This proof-of-principle study provides some of the initial performance data necessary for assessing the scalability and technical viability of electrochemical CO2 conversion technologies. Specifically, we show the following: (1) all electrochemical CO2 conversion systems will produce a net increase in CO2 emissions if they do not integrate with renewable-energy sources, (2) catalyst loading vs activity trends can be used to tune process rates and product distributions, and (3) state-of-the-art renewable-energy technologies are sufficient
Process Design and Economics for the Conversion of Lignocellulosic Biomass to Hydrocarbon Fuels. Thermochemical Research Pathways with In Situ and Ex Situ Upgrading of Fast Pyrolysis Vapors

Energy Technology Data Exchange (ETDEWEB)

Dutta, A.; Sahir, A.; Tan, E.; Humbird, D.; Snowden-Swan, L. J.; Meyer, P.; Ross, J.; Sexton, D.; Yap, R.; Lukas, J.

2015-03-01

This report was developed as part of the U.S. Department of Energy’s Bioenergy Technologies Office’s efforts to enable the development of technologies for the production of infrastructurecompatible, cost-competitive liquid hydrocarbon fuels from biomass. Specifically, this report details two conceptual designs based on projected product yields and quality improvements via catalyst development and process integration. It is expected that these research improvements will be made within the 2022 timeframe. The two conversion pathways detailed are (1) in situ and (2) ex situ upgrading of vapors produced from the fast pyrolysis of biomass. While the base case conceptual designs and underlying assumptions outline performance metrics for feasibility, it should be noted that these are only two of many other possibilities in this area of research. Other promising process design options emerging from the research will be considered for future techno-economic analysis.
A Hierarchy of Homodesmotic Reactions for Thermochemistry

Science.gov (United States)

Schleyer, Paul v. R.

2009-01-01

Chemical equations that balance bond types and atom hybridization to different degrees are often used in computational thermochemistry, for example, to increase accuracy when lower levels of theory are employed. We expose the widespread confusion over such classes of equations and demonstrate that the two most widely used definitions of “homodesmotic” reactions are not equivalent. New definitions are introduced and a consistent hierarchy of reaction classes (RC1 – RC5) for hydrocarbons is constructed: isogyric (RC1) ⊇ isodesmic (RC2) ⊇ hypohomodesmotic (RC3) ⊇ homodesmotic (RC4) ⊇ hyperhomodesmotic (RC5). Each of these successively conserves larger molecular fragments. The concept of isodesmic bond separation reactions is generalized to all classes in this hierarchy, providing a unique sectioning of a given molecule for each reaction type. Several ab initio and density functional methods are applied to the bond separation reactions of 38 hydrocarbons containing five or six carbon atoms. RC4 and RC5 reactions provide bond separation enthalpies with errors consistently less than 0.4 kcal mol−1 across a wide range of theoretical levels, performing significantly better than the other reaction types and far superior to atomization routes. Our recommended bond separation reactions were demonstrated by determining the enthalpies of formation (at 298 K) of 1,3,5-hexatriyne (163.7 ± 0.4 kcal mol−1), 1,3,5,7-octatetrayne (217.6 ± 0.6 kcal mol−1), the larger polyynes C10H2 through C26H2, and an infinite acetylenic carbon chain. PMID:19182999
A New Global Open Source Marine Hydrocarbon Emission Site Database

Science.gov (United States)

Onyia, E., Jr.; Wood, W. T.; Barnard, A.; Dada, T.; Qazzaz, M.; Lee, T. R.; Herrera, E.; Sager, W.

2017-12-01

Hydrocarbon emission sites (e.g. seeps) discharge large volumes of fluids and gases into the oceans that are not only important for biogeochemical budgets, but also support abundant chemosynthetic communities. Documenting the locations of modern emissions is a first step towards understanding and monitoring how they affect the global state of the seafloor and oceans. Currently, no global open source (i.e. non-proprietry) detailed maps of emissions sites are available. As a solution, we have created a database that is housed within an Excel spreadsheet and use the latest versions of Earthpoint and Google Earth for position coordinate conversions and data mapping, respectively. To date, approximately 1,000 data points have been collected from referenceable sources across the globe, and we are continualy expanding the dataset. Due to the variety of spatial extents encountered, to identify each site we used two different methods: 1) point (x, y, z) locations for individual sites and; 2) delineation of areas where sites are clustered. Certain well-known areas, such as the Gulf of Mexico and the Mediterranean Sea, have a greater abundance of information; whereas significantly less information is available in other regions due to the absence of emission sites, lack of data, or because the existing data is proprietary. Although the geographical extent of the data is currently restricted to regions where the most data is publicly available, as the database matures, we expect to have more complete coverage of the world's oceans. This database is an information resource that consolidates and organizes the existing literature on hydrocarbons released into the marine environment, thereby providing a comprehensive reference for future work. We expect that the availability of seafloor hydrocarbon emission maps will benefit scientific understanding of hydrocarbon rich areas as well as potentially aiding hydrocarbon exploration and environmental impact assessements.
Distribution of hydrocarbon-utilizing microorganisms and hydrocarbon biodegradation potentials in Alaskan continental shelf areas

International Nuclear Information System (INIS)

Roubal, G.; Atlas, R.M.

1978-01-01

Hydrocarbon-utilizing microogranisms were enumerated from Alaskan continental shelf areas by using plate counts and a new most-probable-number procedure based on mineralization of 14 C-labeled hydrocarbons. Hydrocarbon utilizers were ubiquitously distributed, with no significant overall concentration differences between sampling regions or between surface water and sediment samples. There were, however, significant seasonal differences in numbers of hydrocarbon utilizers. Distribution of hydrocarbon utilizers within Cook Inlet was positively correlated with occurrence of hydrocarbons in the environment. Hydrocarbon biodegradation potentials were measured by using 14 C-radiolabeled hydrocarbon-spiked crude oil. There was no significant correlation between numbers of hydrocarbon utilizers and hydrocarbon biodegradation potentials. The biodegradation potentials showed large seasonal variations in the Beaufort Sea, probably due to seasonal depletion of available nutrients. Non-nutrient-limited biodegradation potentials followed the order hexadecane > naphthalene >> pristane > benzanthracene. In Cook Inlet, biodegradation potentials for hexadecane and naphthalene were dependent on availability of inorganic nutrients. Biodegradation potentials for pristane and benzanthracene were restricted, probably by resistance to attack by available enzymes in the indigenous population

Green synthesis of gold and silver nanoparticles using gallic acid: catalytic activity and conversion yield toward the 4-nitrophenol reduction reaction

Science.gov (United States)

Park, Jisu; Cha, Song-Hyun; Cho, Seonho; Park, Youmie

2016-06-01

In the present report, gallic acid was used as both a reducing and stabilizing agent to synthesize gold and silver nanoparticles. The synthesized gold and silver nanoparticles exhibited characteristic surface plasmon resonance bands at 536 and 392 nm, respectively. Nanoparticles that were approximately spherical in shape were observed in high-resolution transmission electron microscopy and atomic force microscopy images. The hydrodynamic radius was determined to be 54.4 nm for gold nanoparticles and 33.7 nm for silver nanoparticles in aqueous medium. X-ray diffraction analyses confirmed that the synthesized nanoparticles possessed a face-centered cubic structure. FT-IR spectra demonstrated that the carboxylic acid functional groups of gallic acid contributed to the electrostatic binding onto the surface of the nanoparticles. Zeta potential values of -41.98 mV for the gold nanoparticles and -53.47 mV for the silver nanoparticles indicated that the synthesized nanoparticles possess excellent stability. On-the-shelf stability for 4 weeks also confirmed that the synthesized nanoparticles were quite stable without significant changes in their UV-visible spectra. The synthesized nanoparticles exhibited catalytic activity toward the reduction reaction of 4-nitrophenol to 4-aminophenol in the presence of sodium borohydride. The rate constant of the silver nanoparticles was higher than that of the gold nanoparticles in the catalytic reaction. Furthermore, the conversion yield (%) of 4-nitrophenol to 4-aminophenol was determined using reversed-phase high-performance liquid chromatography with UV detection at 254 nm. The silver nanoparticles exhibited an excellent conversion yield (96.7-99.9 %), suggesting that the synthesized silver nanoparticles are highly efficient catalysts for the 4-nitrophenol reduction reaction.
Green synthesis of gold and silver nanoparticles using gallic acid: catalytic activity and conversion yield toward the 4-nitrophenol reduction reaction

Energy Technology Data Exchange (ETDEWEB)

Park, Jisu [Inje University, College of Pharmacy (Korea, Republic of); Cha, Song-Hyun; Cho, Seonho [Seoul National University, Department of Naval Architecture and Ocean Engineering (Korea, Republic of); Park, Youmie, E-mail: youmiep@inje.ac.kr [Inje University, College of Pharmacy (Korea, Republic of)

2016-06-15

In the present report, gallic acid was used as both a reducing and stabilizing agent to synthesize gold and silver nanoparticles. The synthesized gold and silver nanoparticles exhibited characteristic surface plasmon resonance bands at 536 and 392 nm, respectively. Nanoparticles that were approximately spherical in shape were observed in high-resolution transmission electron microscopy and atomic force microscopy images. The hydrodynamic radius was determined to be 54.4 nm for gold nanoparticles and 33.7 nm for silver nanoparticles in aqueous medium. X-ray diffraction analyses confirmed that the synthesized nanoparticles possessed a face-centered cubic structure. FT-IR spectra demonstrated that the carboxylic acid functional groups of gallic acid contributed to the electrostatic binding onto the surface of the nanoparticles. Zeta potential values of −41.98 mV for the gold nanoparticles and −53.47 mV for the silver nanoparticles indicated that the synthesized nanoparticles possess excellent stability. On-the-shelf stability for 4 weeks also confirmed that the synthesized nanoparticles were quite stable without significant changes in their UV–visible spectra. The synthesized nanoparticles exhibited catalytic activity toward the reduction reaction of 4-nitrophenol to 4-aminophenol in the presence of sodium borohydride. The rate constant of the silver nanoparticles was higher than that of the gold nanoparticles in the catalytic reaction. Furthermore, the conversion yield (%) of 4-nitrophenol to 4-aminophenol was determined using reversed-phase high-performance liquid chromatography with UV detection at 254 nm. The silver nanoparticles exhibited an excellent conversion yield (96.7–99.9 %), suggesting that the synthesized silver nanoparticles are highly efficient catalysts for the 4-nitrophenol reduction reaction.
Green synthesis of gold and silver nanoparticles using gallic acid: catalytic activity and conversion yield toward the 4-nitrophenol reduction reaction

International Nuclear Information System (INIS)

Park, Jisu; Cha, Song-Hyun; Cho, Seonho; Park, Youmie

2016-01-01

In the present report, gallic acid was used as both a reducing and stabilizing agent to synthesize gold and silver nanoparticles. The synthesized gold and silver nanoparticles exhibited characteristic surface plasmon resonance bands at 536 and 392 nm, respectively. Nanoparticles that were approximately spherical in shape were observed in high-resolution transmission electron microscopy and atomic force microscopy images. The hydrodynamic radius was determined to be 54.4 nm for gold nanoparticles and 33.7 nm for silver nanoparticles in aqueous medium. X-ray diffraction analyses confirmed that the synthesized nanoparticles possessed a face-centered cubic structure. FT-IR spectra demonstrated that the carboxylic acid functional groups of gallic acid contributed to the electrostatic binding onto the surface of the nanoparticles. Zeta potential values of −41.98 mV for the gold nanoparticles and −53.47 mV for the silver nanoparticles indicated that the synthesized nanoparticles possess excellent stability. On-the-shelf stability for 4 weeks also confirmed that the synthesized nanoparticles were quite stable without significant changes in their UV–visible spectra. The synthesized nanoparticles exhibited catalytic activity toward the reduction reaction of 4-nitrophenol to 4-aminophenol in the presence of sodium borohydride. The rate constant of the silver nanoparticles was higher than that of the gold nanoparticles in the catalytic reaction. Furthermore, the conversion yield (%) of 4-nitrophenol to 4-aminophenol was determined using reversed-phase high-performance liquid chromatography with UV detection at 254 nm. The silver nanoparticles exhibited an excellent conversion yield (96.7–99.9 %), suggesting that the synthesized silver nanoparticles are highly efficient catalysts for the 4-nitrophenol reduction reaction.
Plasma devices for hydrocarbon reformation

KAUST Repository

Cha, Min Suk

2017-02-16

Plasma devices for hydrocarbon reformation are provided. Methods of using the devices for hydrocarbon reformation are also provided. The devices can include a liquid container to receive a hydrocarbon source, and a plasma torch configured to be submerged in the liquid. The plasma plume from the plasma torch can cause reformation of the hydrocarbon. The device can use a variety of plasma torches that can be arranged in a variety of positions in the liquid container. The devices can be used for the reformation of gaseous hydrocarbons and/or liquid hydrocarbons. The reformation can produce methane, lower hydrocarbons, higher hydrocarbons, hydrogen gas, water, carbon dioxide, carbon monoxide, or a combination thereof.
Conversion of tritium gas to tritiated water in the environment

International Nuclear Information System (INIS)

Noguchi, Hiroshi; Kato, Shohei

1985-01-01

The literature on conversion of tritium gas to tritiated water in various environments is reviewed. The conversion mechanisms and the conversion rates are as follows. 1. In the oxidation with oxygen and the isotopic exchange with water, tritium β-rays and metal catalyst are effective. The oxidation rate is ∼ 0.02 %/day at initial tritium concentration ≤ 10 -2 Ci/l and ∼ 2 %/day at 1 Ci/l. In the presence of oxygen and water, it is not clear whether the exchange reaction occurs or not because of the small amount of data. 2. For biological conversion, soil microorganisms contribute significantly. The conversion rate is greater than 10 %/hr. The tritium gas deposition velocity, which includes the uptake rate of tritium gas by soil and the conversion rate, ranges from 0.0025 to 0.11 cm/sec and is influenced by temperature and moisture of the soil. 3. Tritium gas is converted to the tritiated water through the reaction with hydroxyl radical produced by sunlight in the atmosphere. (author)
Growth and Destruction of PAH Molecules in Reactions with Carbon Atoms

Energy Technology Data Exchange (ETDEWEB)

Krasnokutski, Serge A.; Huisken, Friedrich; Jäger, Cornelia; Henning, Thomas [Laboratory Astrophysics Group of the Max Planck Institute for Astronomy at the Friedrich Schiller University Jena, Helmholtzweg 3, D-07743 Jena (Germany)

2017-02-10

A very high abundance of atomic carbon in the interstellar medium (ISM), and the high reactivity of these species toward different hydrocarbon molecules including benzene, raise questions regarding the stability of polycyclic aromatic hydrocarbon (PAH) molecules in space. To test the efficiency of destruction of PAH molecules via reactions with atomic carbon, we performed a set of laboratory and computational studies of the reactions of naphthalene, anthracene, and coronene molecules with carbon atoms in the ground state. The reactions were investigated in liquid helium droplets at T = 0.37 K and by quantum chemical computations. Our studies suggest that all small and all large catacondensed PAHs react barrierlessly with atomic carbon, and therefore should be efficiently destroyed by such reactions in a broad temperature range. At the same time, large compact pericondensed PAHs should be more inert toward such a reaction. In addition, taking into account their higher photostability, much higher abundances of pericondensed PAHs should be expected in various astrophysical environments. The barrierless reactions between carbon atoms and small PAHs also suggest that, in the ISM, these reactions could lead to the bottom-up formation of PAH molecules.
Petroleum hydrocarbons

International Nuclear Information System (INIS)

Farrington, J.W.; Teal, J.M.; Parker, P.L.

1976-01-01

Methods for analysis of petroleum hydrocarbons in marine samples are presented. Types of hydrocarbons present and their origins are discussed. Principles and methods of analysis are outlined. Infrared spectrometry, uv spectrometry, gas chromatography, mass spectroscopy, and carbon 14 measurements are described
The rate of the reaction between C2H and C2H2 at interstellar temperatures

Science.gov (United States)

Herbst, E.; Woon, D. E.

1997-01-01

The reaction between the radical C2H and the stable hydrocarbon C2H2 is one of the simplest neutral-neutral hydrocarbon reactions in chemical models of dense interstellar clouds and carbon-rich circumstellar shells. Although known to be rapid at temperatures > or = 300 K, the reaction has yet to be studied at lower temperatures. We present here ab initio calculations of the potential surface for this reaction and dynamical calculations to determine its rate at low temperature. Despite a small potential barrier in the exit channel, the calculated rate is large, showing that this reaction and, most probably, more complex analogs contribute to the formation of complex organic molecules in low-temperature sources.
Linear-dendritic supramolecular complexes as nanoscale reaction vessels for "green" chemistry. Diels-Alder reactions between fullerene C60 and polycyclic aromatic hydrocarbons in aqueous medium.

Science.gov (United States)

Simonyan, Arsen; Gitsov, Ivan

2008-10-21

This study describes the first Diels-Alder (DA) reaction performed in aqueous medium with highly hydrophobic compounds-fullerene (C 60) as the dienophile and anthracene (An) or tetracene (Tet) as the dienes, respectively. The reactions are performed in nanocontainers, constructed by self-assembly of linear-dendritic amphiphilic copolymers with poly(ethylene glycol), PEG or poly(ethylene oxide), PEO as the hydrophilic blocks and poly(benzyl ether) monodendrons as the hydrophobic fragments: G3PEO13k, dG3 and dG2. Comparative studies under identical conditions are carried out with an amphiphilic linear-linear copolymer, poly(styrene)1800- block-PEO2100, PSt-PEO, and the nonionic surfactant Igepal CO-720, IP720. The binding affinity of supermolecules built of these amphiphiles toward the DA reagents decreases in the following order: G3PEO13k > dG3 > PSt-PEO > dG2 > IP720. The kinetic constant of binding is evaluated for tetracene and decreases in a similar fashion: 5 x 10 (-7) M/min (G3PEO13k), through 4 x 10 (-7) M/min (PSt-PEO) down to 1.5 x 10 (-7) M/min for IP720. The mobility of substrates encapsulated in the micellar core, estimated by pyrene fluorescence decay, is 95-121 ns for the micelles of the linear-dendritic copolymers and notably higher for PSt-PEO (152 ns), revealing the much denser interior of the linear analogue. The apparent kinetic constant for the DA reaction of C 60 and Tet within the G3PEO13k supermolecule in aqueous medium is markedly higher than in organic solvent (toluene), 208 vs 1.82 M /min. With G3PEO13k the conversions reach 49% for the DA reaction between C 60 and An, and 55% for C 60 and Tet. Besides the monoadduct (26.5% yield) the reaction with An produces exclusively increasing amounts of D 2 h -symmetric antipodal bis-adduct, whose yield reaches up to 22.5% after 48 h. In addition to the environmentally friendly conditions notable advantages of the synthetic strategy described are the extended stability of the linear
Low energy ion-molecule reactions

International Nuclear Information System (INIS)

Farrar, J.M.

1986-01-01

The authors work during the past year has focused on several problems in the condensation reactions of C + and CH 3 + with small molecules, particularly hydrocarbons. Their emphasis has been on understanding the dynamics of collision complex formation and isomerization of transient intermediates along the reaction coordinate. In many ionic reactions, intermediates having non-classical valence structures may be nearly as stable as their classical analogs, in contrast with neutral systems where the non-classical structures are much less stable. The C + + NH 3 system shows this behavior, indicating that the non-classical HCNH 2 + structure formed by insertion of C + into the N-H bond serves as a precursor to the products. N-H bond cleavage in this intermediate to form HCNH + occurs over a large barrier and occurs more readily than the 1,2 hydrogen atom shift to form the classical H 2 C = NH + intermediate. Their experimental kinetic energy distribution for this channel is consistent with the presence of a large exit channel barrier. Their recently published work on C + + H 2 O also demonstrates this phenomenon. The CHOH + hydroxycarbene cation serves as the initial intermediate and isomerization to the classical H 2 CO + cation is competitive with O-H or C-H cleavage to yield the formyl, HCO + , or isoformyl, COH + , cations. They have also completed studies on the reactions of C + with O 2 , CH 3 OH, HCN, and the two-carbon containing hydrocarbons ethane, ethylene, and acetylene
Selective Conversion of Lignin-Derivable 4-Alkylguaiacols to 4-Alkylcyclohexanols over Noble and Non-Noble-Metal Catalysts

Energy Technology Data Exchange (ETDEWEB)

Schutyser, Wouter; Van den Bossche, Gil; Raaffels, Anton; Van den Bosch, Sander; Koelewijn, Steven-Friso; Renders, Tom; Sels, Bert F.

2016-10-03

Recent lignin-first catalytic lignocellulosic biorefineries produce large quantities of two potential platform chemicals, 4-n-propylguaiacol (PG) and 4-n-propylsyringol. Because conversion into 4-n-propylcyclohexanol (PCol), a precursor for novel polymer building blocks, presents a promising valorization route, reductive demethoxylation of PG was examined here in the liquid-phase over three commercial hydrogenation catalysts, viz. 5 wt % Ru/C, 5 wt % Pd/C and 65 wt % Ni/SiO2-Al2O3, at elevated temperatures ranging from 200 to 300 degrees C under hydrogen atmosphere. Kinetic profiles suggest two parallel conversion pathways: Pathway I involves PG hydrogenation to 4-n-propyl-2-methoxycyclohexanol (PMCol), followed by its demethoxylation to PCol, whereas Pathway II constitutes PG hydrodemethoxylation to 4-n-propylphenol (PPh), followed by its hydrogenation into PCol. The slowest step in the catalytic formation of PCol is the reductive methoxy removal from PMCol. Moreover, under the applied reaction conditions, PCol may react further into hydrocarbons. The following criteria are therefore essential to reach a high PCol yield: (i) catalytic pathway II is preferred as this route does not involve stable intermediates; (ii) reactivity of PMCol should be higher than that of PCol, and (iii) the overall carbon balance should be high. Both the catalyst type and the reaction conditions have a substantial impact on the PCol yield. Only the commercial Ni catalyst meets the three criteria, provided the reaction is performed at 250 degrees C in hexadecane. Additional advantages of this solvent choice are a high boiling point (low operational pressure in closed reactor systems), high solubility of PG and derived products, high thermal, reductive stability, and easy derivability from fatty biomass feedstock. This Ni catalyst also showed an excellent stability in recycling runs and is capable of converting highly concentrated (up to 20 wt %) PG in hexadecane. Ru and Pd on carbon
Possibilities of rationalizing gas storage in hydrocarbon deposits

International Nuclear Information System (INIS)

Stricker; Gilch; Kretzschmar

1990-01-01

A number of criteria on the utilization of gas fields for storage and major methods for rationalizing such storage reservoirs (such as pressure optimization and increase of well performance) are indicated. The pressure reduction/ pressure increase conducted in phases and the investigations involved are discussed in detail. In particular, experiences and results for fixing the maximum allowable storage pressures are analyzed critically. Problems of gas blending in case of different compositions of residual gas and storage gas are dealt with. Finally, some recommendations are given for the necessary investigations to increase efficiency in the conversion of depleted hydrocarbon deposits to gas storage. 3 figs
Catalytic conversion of ethanol on H-Y zeolite

Directory of Open Access Journals (Sweden)

Čegar Nedeljko

2005-01-01

Full Text Available The catalytic activity of the H-form of synthetic zeolite NaY was examined in this study. The catalytic activity was determined according to the rate of ethanol conversion in a gas phase in the static system. In the conversion of ethanol on synthetic NaY zeolite at 585, 595, and 610 K, on which the reaction develops at an optimal rate, ethene and diethyl ether are evolved in approximately the same quantity. After transforming the NaY zeolite into the H-form, its catalytic activity was extremely increases so, the reaction develops at a significantly lower temperature with a very large increase in the reaction rate. The distribution of the products also changes, so that at lower temperatures diethyl ether is elvolved in most cases, and the development of ethene is favored at higher ones, and after a certain period of time there is almost complete conversion of ethanol into ethene. The increase in catalytic activity, as well as the change of selectivity of conversion of ethanol on the H-form of zeolite, is the result of removing Na+ cations in the NaY zeolite, so that more acidic catalyst is obtained which contains a number of acidic catalytically active centers, as well as a more powerful one compared to the original NaY zeolite.
Converting high boiling hydrocarbons

Energy Technology Data Exchange (ETDEWEB)

Terrisse, H; DuFour, L

1929-02-12

A process is given for converting high boiling hydrocarbons into low boiling hydrocarbons, characterized in that the high boiling hydrocarbons are heated to 200 to 500/sup 0/C in the presence of ferrous chloride and of such gases as hydrogen, water gas, and the like gases under a pressure of from 5 to 40 kilograms per square centimeter. The desulfurization of the hydrocarbons occurs simultaneously.
Final Technical Report: Tandem and Bimetallic Catalysts for Oxidative Dehydrogenation of Light Hydrocarbon with Renewable Feedstock

Energy Technology Data Exchange (ETDEWEB)

Abu-Omar, Mahdi [Purdue Univ., West Lafayette, IN (United States)

2017-01-06

An estimated 490 million metric tons of lignocellulosic biomass is available annually from U.S. agriculture and forestry. With continuing concerns over greenhouse gas emission, the development of efficient catalytic processes for conversion of biomass derived compounds is an important area of research. Since carbohydrates and polyols are rich in oxygen, approximately one oxygen atom per carbon, removal of hydroxyl groups via deoxygenation is needed. The necessary hydrogen required for hydrodeoxygenation (HDO) would either come from reforming biomass itself or from steam reforming of natural gas. Both processes contribute to global CO2 emission. The hope is that eventually renewable sources such as wind and solar for hydrogen production will become more viable and economic in the future. In the meantime, unconventional natural gas production in North America has boomed. As a result, light hydrocarbons present an opportunity when coupled with biomass derived oxygenates to generate valuable products from both streams without co-production of carbon dioxide. This concept is the focus of our current funding period. The objective of the project requires coupling two different types of catalysis, HDO and dehydrogenation. Our hypothesis was formulated around our success in establishing oxorhenium catalysts for polyol HDO reactions and known literature precedence for the use of iridium hydrides in alkane dehydrogenation. To examine our hypothesis we set out to investigate the reaction chemistry of binuclear complexes of oxorhenium and iridium hydride.
Effective conversion of biomass tar into fuel gases in a microwave reactor

Energy Technology Data Exchange (ETDEWEB)

Anis, Samsudin, E-mail: samsudin-anis@yahoo.com [Department of Mechanical Engineering, Universitas Negeri Semarang, Kampus Sekaran, Gunungpati, 50229 Semarang, 8508101 (Indonesia); Zainal, Z. A., E-mail: mezainal@usm.my [School of Mechanical Engineering, Universiti Sains Malaysia, Engineering Campus, 14300 Nibong Tebal, Penang (Malaysia)

2016-06-03

This work deals with conversion of naphthalene (C{sub 10}H{sub 8}) as a biomass tar model compound by means of thermal and catalytic treatments. A modified microwave oven with a maximum output power of 700 W was used as the experimental reactor. Experiments were performed in a wide temperature range of 450-1200°C at a predetermined residence time of 0.24-0.5 s. Dolomite and Y-zeolite were applied to convert naphthalene catalytically into useful gases. Experimental results on naphthalene conversion showed that conversion efficiency and yield of gases increased significantly with the increase of temperature. More than 90% naphthalene conversion efficiency was achieved by thermal treatment at 1200°C and 0.5 s. Nevertheless, this treatment was unfavorable for fuel gases production. The main product of this treatment was soot. Catalytic treatment provided different results with that of thermal treatment in which fuel gases formation was found to be the important product of naphthalene conversion. At a high temperature of 900°C, dolomite had better conversion activity where almost 40 wt.% of naphthalene could be converted into hydrogen, methane and other hydrocarbon gases.
Catalytic Conversion of Cellulose to Levulinic Acid by Metal Chlorides

Directory of Open Access Journals (Sweden)

Beixiao Zhang

2010-08-01

Full Text Available The catalytic performance of various metal chlorides in the conversion of cellulose to levulinic acid in liquid water at high temperatures was investigated. The effects of reaction parameters on the yield of levulinic acid were also explored. The results showed that alkali and alkaline earth metal chlorides were not effective in conversion of cellulose, while transition metal chlorides, especially CrCl3, FeCl3 and CuCl2 and a group IIIA metal chloride (AlCl3, exhibited high catalytic activity. The catalytic performance was correlated with the acidity of the reaction system due to the addition of the metal chlorides, but more dependent on the type of metal chloride. Among those metal chlorides, chromium chloride was found to be exceptionally effective for the conversion of cellulose to levulinic acid, affording an optimum yield of 67 mol % after a reaction time of 180 min, at 200 °C, with a catalyst dosage of 0.02 M and substrate concentration of 50 wt %. Chromium metal, most of which was present in its oxide form in the solid sample and only a small part in solution as Cr3+ ion, can be easily separated from the resulting product mixture and recycled. Finally, a plausible reaction scheme for the chromium chloride catalyzed conversion of cellulose in water was proposed.
Analytical solutions for non-linear conversion of a porous solid particle in a gas–II. Non-isothermal conversion and numerical verification

NARCIS (Netherlands)

Brem, Gerrit; Brouwers, J.J.H.

1990-01-01

In Part I, analytical solutions were given for the non-linear isothermal heterogeneous conversion of a porous solid particle. Account was taken of a reaction rate of general order with respect to the gas reactant, intrinsic reaction surface area and effective pore diffusion, which change with solid
Analytical solutions for non-linear conversion of a porous solid particle in a gas : II. non-isothermal conversion and numerical verification

NARCIS (Netherlands)

Brem, G.; Brouwers, J.J.H.

1990-01-01

In Part I, analytical solutions were given for the non-linear isothermal heterogeneous conversion of a porous solid particle. Account was taken of a reaction rate of general order with respect to the gas reactant, intrinsic reaction surface area and effective pore diffusion, which change with solid
Mesoporous Zeolite Single Crystals for Catalytic Hydrocarbon Conversion

DEFF Research Database (Denmark)

Schmidt, I.; Christensen, Claus H.; Kustova, Marina

2005-01-01

Recently, mesoporous zeolite single crystals were discovered. They constitute a novel family of materials that features a combined micropore and mesopore architecture within each individual crystal. Here, we briefly summarize recent catalytic results from cracking and isomerization of alkalies......, alkylation of aromatics and present new results on isomerization of aromatics. Specifically, the shape-selective isomerization of meta-xylenc into para-xylene and ortho-xylene is studied. In all these reactions, rnesoporous zeolite single crystals prove to be unique catalysts since they provide easy...... transport to and from active sites and at the same time maintain the shape-selectivity required. Thus, all these results support the idea that the beneficial effect of the mesopores system in the mesoporous zeolite single crystals call be solely attributed to enhanced mass transport....

Catalytic conversion of methane: Carbon dioxide reforming and oxidative coupling

KAUST Repository

Takanabe, Kazuhiro

2012-01-01

Natural gas conversion remains one of the essential technologies for current energy needs. This review focuses on the mechanistic aspects of the development of efficient and durable catalysts for two reactions, carbon dioxide reforming and the oxidative coupling of methane. These two reactions have tremendous technological significance for practical application in industry. An understanding of the fundamental aspects and reaction mechanisms of the catalytic reactions reviewed in this study would support the design of industrial catalysts. CO 2 reforming of methane utilizes CO 2, which is often stored in large quantities, to convert as a reactant. Strategies to eliminate carbon deposition, which is the major problem associated with this reaction, are discussed. The oxidative coupling of methane directly produces ethylene in one reactor through a slightly exothermic reaction, potentially minimizing the capital cost of the natural gas conversion process. The focus of discussion in this review will be on the attainable yield of C 2 products by rigorous kinetic analyses.
Effect of Water on Ethanol Conversion over ZnO

Energy Technology Data Exchange (ETDEWEB)

Rahman, Muhammad Mahfuzur; Davidson, Stephen D.; Sun, Junming; Wang, Yong

2015-10-01

This work focuses on understanding the role of water on ethanol conversion over zinc oxide (ZnO). It was found that a competitive adsorption between ethanol and water occurs on ZnO, which leads to the blockage of the strong Lewis acid site by water on ZnO. As a result, both dehydration and dehydrogenation reactions are inhibited. However, the extent of inhibition for dehydration is orders of magnitude higher than that for dehydrogenation, leading to the shift of reaction pathway from ethanol dehydration to dehydrogenation. In the secondary reactions for acetaldehyde conversion, water inhibits the acetaldehyde aldol-condensation to crotonaldehyde, favoring the oxidation of acetaldehyde to acetic acid, and then to acetone via ketonization at high temperature (i.e., 400 °C).
Production of hydrocarbons

Energy Technology Data Exchange (ETDEWEB)

Day, D T; Day, R E

1920-04-27

A process is disclosed of converting hydro-carbon oils having high boiling points to hydro-carbon oils having low boiling points, which process comprises adding the oil to be treated to a mass of hydro-carbon oil bearing shale, passing the shale with the oil through a conveyor retort and subjecting the material while in the retort to a heat treatment involving a temperature of at least 500/sup 0/F.
A computational study of ethylene–air sooting flames: Effects of large polycyclic aromatic hydrocarbons

KAUST Repository

Selvaraj, Prabhu; Arias, Paul G.; Lee, Bok Jik; Im, Hong G.; Wang, Yu; Gao, Yang; Park, Sungwoo; Sarathy, Mani; Lu, Tianfeng; Chung, Suk-Ho

2015-01-01

formation to various chemical pathways for large polycyclic aromatic hydrocarbons (PAH). The gas-phase chemical mechanism adopted the KAUST-Aramco PAH Mech 1.0, which utilized the AramcoMech 1.3 for gas-phase reactions validated for up to C2 fuels
An efficient catalyst for asymmetric Reformatsky reaction

Indian Academy of Sciences (India)

rate enantioselectivity using N,N-dialkylnorephedrines as chiral ligands. ..... temperatures also, there was no product conversion. ... Optimization of reaction conditions for asymmetric Reformatsky reaction between benzaldehyde and α-.
Heterogeneous Reactions of Limonene on Mineral Dust: Impacts of Adsorbed Water and Nitric Acid.

Science.gov (United States)

Lederer, Madeline R; Staniec, Allison R; Coates Fuentes, Zoe L; Van Ry, Daryl A; Hinrichs, Ryan Z

2016-12-08

Biogenic volatile organic compounds (BVOCs), including the monoterpene limonene, are a major source of secondary organic aerosol (SOA). While gas-phase oxidation initiates the dominant pathway for BVOC conversion to SOA, recent studies have demonstrated that biogenic hydrocarbons can also directly react with acidic droplets. To investigate whether mineral dust may facilitate similar reactive uptake of biogenic hydrocarbons, we studied the heterogeneous reaction of limonene with mineral substrates using condensed-phase infrared spectroscopy and identified the formation of irreversibly adsorbed organic products. For kaolinite, Arizona Test Dust, and silica at 30% relative humidity, GC-MS identified limonene-1,2-diol as the dominant product with total organic surface concentrations on the order of (3-5) × 10 18 molecules m -2 . Experiments with 18 O-labeled water support a mechanism initiated by oxidation of limonene by surface redox sites forming limonene oxide followed by water addition to the epoxide to form limonenediol. Limonene uptake on α-alumina, γ-alumina, and montmorillonite formed additional products in high yield, including carveol, carvone, limonene oxide, and α-terpineol. To model tropospheric processing of mineral aerosol, we also exposed each mineral substrate to gaseous nitric acid prior to limonene uptake and identified similar surface adsorbed products that were formed at rates 2 to 5 times faster than without nitrate coatings. The initial rate of reaction was linearly dependent on gaseous limonene concentration between 5 × 10 12 and 5 × 10 14 molecules cm -3 (0.22-20.5 ppm) consistent with an Eley-Rideal-type mechanism in which gaseous limonene reacts directly with reactive surface sites. Increasing relative humidity decreased the amount of surface adsorbed products indicating competitive adsorption of surface adsorbed water. Using a laminar flow tube reactor we measured the uptake coefficient for limonene on kaolinite at 25% RH to range from
Hydrodeoxygenation processes: advances on catalytic transformations of biomass-derived platform chemicals into hydrocarbon fuels.

Science.gov (United States)

De, Sudipta; Saha, Basudeb; Luque, Rafael

2015-02-01

Lignocellulosic biomass provides an attractive source of renewable carbon that can be sustainably converted into chemicals and fuels. Hydrodeoxygenation (HDO) processes have recently received considerable attention to upgrade biomass-derived feedstocks into liquid transportation fuels. The selection and design of HDO catalysts plays an important role to determine the success of the process. This review has been aimed to emphasize recent developments on HDO catalysts in effective transformations of biomass-derived platform molecules into hydrocarbon fuels with reduced oxygen content and improved H/C ratios. Liquid hydrocarbon fuels can be obtained by combining oxygen removal processes (e.g. dehydration, hydrogenation, hydrogenolysis, decarbonylation etc.) as well as by increasing the molecular weight via C-C coupling reactions (e.g. aldol condensation, ketonization, oligomerization, hydroxyalkylation etc.). Fundamentals and mechanistic aspects of the use of HDO catalysts in deoxygenation reactions will also be discussed. Copyright © 2014 Elsevier Ltd. All rights reserved.
Photo-assisted removal of fuel oil hydrocarbons from wood and concrete.

Science.gov (United States)

Popova, Inna E; Kozliak, Evguenii I

2008-08-01

A novel photo-treatment to decontaminate building structural elements polluted with fuel oil hydrocarbons as a result of spillage and/or a catastrophic flood was examined. A proof-of-concept study evaluating the photocatalytic removal of hydrocarbons (n-hexadecane and fuel oil #2) from contaminated wood (southern yellow pine) and concrete was conducted using scintillation counting (with (14)C-labeled n-hexadecane) and gas chromatography. Contaminated samples were irradiated by UV or fluorescent light in the absence or presence of a photocatalyst, TiO(2). As a result of the treatment, under various scenarios, up to 80-98% of the originally applied n-hexadecane was removed, within a wide range of contaminant concentrations (4-250 mg/g wood). The essential treatment time increased from 1-7 days for low concentrations to several weeks for high concentrations. Mass balance experiments showed that the only product formed from (14)C-labeled n-hexadecane in detectable amounts was (14)CO(2). For low amounts of applied hydrocarbon (4-20 mg/g wood), the overall process rate was limited by the contaminant transport/mobility whereas for high n-hexadecane concentrations (150-250 mg/g, corresponding to 50-80% filling of wood pores), the key factor was the photochemical reaction. Photodegradation experiments conducted with standard heating fuel oil #2 (a representative real-world contaminant) resulted in a significant (up to 80%) photochemical removal of mid-size hydrocarbons (C(13)-C(17)) in 3 weeks whereas heavier hydrocarbons (> C(17)) were not affected; light hydrocarbons (evaporation. These results point toward a promising technique to reclaim wooden and concrete structures contaminated with semi-volatile chemicals.
Minimum Energy Pathways for Chemical Reactions

Science.gov (United States)

Walch, S. P.; Langhoff, S. R. (Technical Monitor)

1995-01-01

Computed potential energy surfaces are often required for computation of such parameters as rate constants as a function of temperature, product branching ratios, and other detailed properties. We have found that computation of the stationary points/reaction pathways using CASSCF/derivative methods, followed by use of the internally contracted CI method to obtain accurate energetics, gives useful results for a number of chemically important systems. The talk will focus on a number of applications to reactions leading to NOx and soot formation in hydrocarbon combustion.
Mechanistic aspects of ionic reactions in flames

DEFF Research Database (Denmark)

Egsgaard, H.; Carlsen, L.

1993-01-01

Some fundamentals of the ion chemistry of flames are summarized. Mechanistic aspects of ionic reactions in flames have been studied using a VG PlasmaQuad, the ICP-system being substituted by a simple quartz burner. Simple hydrocarbon flames as well as sulfur-containing flames have been investigated...
Performance of a Throttle Cycle Refrigerator with Nitrogen-Hydrocarbon and Argon-Hydrocarbon Mixtures

Science.gov (United States)

Venkatarathnam, G.; Senthil Kumar, P.; Srinivasa Murthy, S.

2004-06-01

Throttle cycle refrigerators are a class of vapor compression refrigerators that can provide refrigeration at cryogenic temperatures and operate with refrigerant mixtures. The performance of our prototype refrigerators with nitrogen-hydrocarbon, nitrogen-hydrocarbon-helium and argon-hydrocarbon refrigerant mixtures is presented in this paper.
Petroleum hydrocarbons and polycyclic aromatic hydrocarbons (PAHs) in Hong Kong marine sediments

International Nuclear Information System (INIS)

Zheng, G.J.; Richardson, B.J.

1999-01-01

A total of 20 surficial sediment samples, obtained from Hong Kong coastal waters, were analysed for petroleum hydrocarbons (PHCs) and a suite of 15 polycyclic aromatic hydrocarbons (PAHs). The results indicate that Hong Kong coastal sediments are often seriously polluted with petroleum related hydrocarbons. This is especially so in heavily urbanised or industrialized localities, such as Kowloon Bay (Victoria Harbour), Tsing Yi North and Tolo Harbour. Petroleum hydrocarbon pollutants in marine sediments are believed to be mainly derived from the transportation of oil, shipping activities, spillages, and industrial, stormwater and waste wastewater discharge. The ratio of unresolved complex mixture (UCM) to n-alkanes, carbon preference index (CPI), and n-C 16 values indicate that the main contribution to petroleum hydrocarbon contamination is via oil and its products. Pollutant sources appear to be stable and continuing when compared with previous data. (author)
Purifying hydrocarbons

Energy Technology Data Exchange (ETDEWEB)

Demoulins, H D; Garner, F H

1923-02-07

Hydrocarbon distillates, including natural gases and vapors produced by cracking hydrocarbon oils, are desulfurized etc. by treating the vapor with an aqueous alkaline solution of an oxidizing agent. The hydrocarbons may be previously purified by sulfuric acid. In examples aqueous solutions of sodium or calcium hydrochlorite containing 1.5 to 5.0 grams per liter of available chlorine and sufficient alkali to give an excess of 0.1 percent in the spent reagent are preheated to the temperature of the vapor, and either sprayed or atomized into the vapors near the outlet of the dephlegmator or fractionating tower, or passed in countercurrent to the vapors through one or a series of scrubbers.
Configuration of a pulse radiolysis system for the study of gas-phase reactions and kinetic investigations of the reactions of hydroxyl radicals with methyl and ethyl radicals

International Nuclear Information System (INIS)

Fagerstroem, K.

1993-01-01

The work that is presented in this thesis deals with the assembling and testing of a pulse radiolysis system for kinetic studies of gas-phase reactions as well as with the kinetics of the gas-phase reactions of hydroxyl radicals with methyl and ethyl radicals. These radicals are very important as these are formed at an early stage in hydrocarbon combustion processes. The two studied reactions are key reactions in those processes. (6 refs., 4 figs., 2 tabs.)
Reactions of BBr(n)(+) (n = 0--2) at fluorinated and hydrocarbon self-assembled monolayer surfaces: observations of chemical selectivity in ion--surface scattering.

Science.gov (United States)

Wade, N; Shen, J; Koskinen, J; Cooks, R G

2001-07-01

Ion-surface reactions involving BBr(n)(+) (n = 0--2) with a fluorinated self-assembled monolayer (F-SAM) surface were investigated using a multi-sector scattering mass spectrometer. Collisions of the B(+) ion yield BF(2)(+) at threshold energy with the simpler product ion BF(+)* appearing at higher collision energies and remaining of lower abundance than BF(2)(+) at all energies examined. In addition, the reactively sputtered ion CF(+) accompanies the formation of BF(2)(+) at low collision energies. These results stand in contrast with previous data on the ion-surface reactions of atomic ions with the F-SAM surface in that the threshold and most abundant reaction products in those cases involved the abstraction of a single fluorine atom. Gas-phase enthalpy data are consistent with BF(2)(+) being the thermodynamically favored product. The fact that the abundance of BF(2)(+) is relatively low and relatively insensitive to changes in collision energy suggests that this reaction proceeds through an entropically demanding intermediate at the vacuum--surface interface, one which involves interaction of the B(+) ion simultaneously with two fluorine atoms. By contrast with the reaction of B(+), the odd-electron species BBr(+)* reacts with the F-SAM surface to yield an abundant single-fluorine abstraction product, BBrF(+). Corresponding gas-phase ion--molecule experiments involving B(+) and BBr(+)* with C(6)F(14) also yield the products BF(+)* and BF(2)(+), but only in extremely low abundances and with no preference for double fluorine abstraction. Ion--surface reactions were also investigated for BBr(n)(+) (n = 0-2) with a hydrocarbon self-assembled monolayer (H-SAM) surface. Reaction of the B(+) ion and dissociative reactions of BBr(+)* result in the formation of BH(2)(+), while the thermodynamically less favorable product BH(+)* is not observed. Collisions of BBr(2)(+) with the H-SAM surface yield the dissociative ion-surface reaction products, BBrH(+) and BBrCH(3
Interaction of oxides of nitrogen and aromatic hydrocarbons under simulated atmospheric conditions

International Nuclear Information System (INIS)

Obrien, R.J.; Green, P.J.; Doty, R.A.; Vanderzanden, J.W.; Easton, R.R.; Irwin, R.P.

1979-01-01

The reactions of nitrogen oxides with aromatic hydrocarbons under simulated atmospheric conditions are investigated. Gaseous reaction products formed when toluene is irradiated under simulated atmospheric conditions in the presence of nitrogen oxides were analyzed by gas chromatography. Reaction products detected include acetylene, water, acetaldehyde, acetone, toluene, benzaldehyde, ortho-, meta- and para-cresol, benzyl nitrate and meta- and para-nitrotoluene. Reaction mechanisms yielding the various products are illustrated. The assumption that all the nitrogen oxides observed to be lost from the reaction products can be accounted for by nitric acid formation in the absence of ozone formation is verified by a model in which the hydroxyl radical is assumed to be the only means of removing toluene. Under conditions in which ozone is formed, nitrogen oxide loss is accounted for by ozone formation in addition to nitric acid formation
Microbial Physiology of the Conversion of Residual Oil to Methane: A Protein Prospective

Science.gov (United States)

Morris, Brandon E. L.; Bastida-Lopez, Felipe; von Bergen, Martin; Richnow, Hans-Hermann; Suflita, Joseph M.

2010-05-01

Traditional petroleum recovery techniques are unable to extract the majority of oil in most petroliferous deposits. The recovery of even a fraction of residual hydrocarbon in conventional reserves could represent a substantive energy supply. To this end, the microbial conversion of residual oil to methane has gained increasing relevance in recent years [1,2]. Worldwide demand for methane is expected to increase through 2030 [3], as it is a cleaner-burning alternative to traditional fuels [4]. To investigate the microbial physiology of hydrocarbon-decomposition and ultimate methanogenesis, we initiated a two-pronged approach. First, a model alkane-degrading sulfate-reducing bacterium, Desulfoglaeba alkanexedens, was used to interrogate the predominant metabolic pathway(s) differentially expressed during growth on either n-decane or butyrate. A total of 81 proteins were differentially expressed during bacterial growth on butyrate, while 100 proteins were unique to the alkane-grown condition. Proteins related to alkylsuccinate synthase, or the homologous 1-methyl alkylsuccinate synthase, were identified only in the presence of the hydrocarbon. Secondly, we used a newly developed stable isotope probing technique [5] targeted towards proteins to monitor the flux of carbon through a residual oil-degrading bacterial consortium enriched from a gas-condensate contaminated aquifer [1]. Combined carbon and hydrogen stable isotope fractionation identified acetoclastic methanogenesis as the dominant process in this system. Such findings agree with the previous clone library characterization of the consortium. Furthermore, hydrocarbon activation was determined to be the rate-limiting process during the net conversion of residual oil to methane. References 1. Gieg, L.M., K.E. Duncan, and J.M. Suflita, Bioenegy production via microbial conversion of residual oil to natural gas. Appl Environ Micro, 2008. 74(10): p. 3022-3029. 2. Jones, D.M., et al., Crude-oil biodegradation via
Collisions of polyatomic ions with surfaces: incident energy partitioning and chemical reactions

International Nuclear Information System (INIS)

Zabka, J.; Roithova, J.; Dolejsek, Z.; Herman, Z.

2002-01-01

Collision of polyatomic ions with surfaces were investigated in ion-surface scattering experiments to obtain more information on energy partitioning in ion-surface collision and on chemical reactions at surfaces. Mass spectra, translation energy and angular distributions of product ions were measured in dependence on the incident energy and the incident angle of polyatomic projectiles. From these data distributions of energy fractions resulting in internal excitation of the projectile, translation energy of the product ions, and energy absorbed by the surface were determined. The surface investigated were a standard stainless steel surface, covered by hydrocarbons, carbon surfaces at room and elevated temperatures, and several surfaces covered by a self-assembled monolayers (C 12 -hydrocarbon SAM, C 11 -perfluorohydrocarbon SAM, and C 11 hydrocarbon with terminal -COOH group SAM). The main processes observed at collision energies of 10 - 50 eV were: neutralization of the ions at surfaces, inelastic scattering and dissociations of the projectile ions, quasi elastic scattering of the projectile ions, and chemical reactions with the surface material (usually hydrogen-atom transfer reactions). The ion survival factor was estimated to be a few percent for even-electron ions (like protonated ethanol ion, C 2 H 5 O + , CD 5 + ) and about 10 - 10 2 times lower for radical ions (like ethanol and benzene molecular ions, CD 4 + ). In the polyatomic ion -surface energy transfer experiments, the ethanol molecular ion was used as a well-characterized projectile ion. The results with most of the surfaces studied showed in the collision energy range of 13 - 32 eV that most collisions were strongly inelastic with about 6 - 8 % of the incident projectile energy transformed into internal excitation of the projectile (independent of the incident angle) and led partially to its further dissociation in a unimolecular way after the interaction with the surface. The incident energy
Performance characterization of CNTs and γ-Al{sub 2}O{sub 3} supported cobalt catalysts in Fischer-Tropsch reaction

Energy Technology Data Exchange (ETDEWEB)

Ali, Sardar, E-mail: alikhan-635@yahoo.com [Centralized Analytical Laboratory, Universiti Teknologi PETRONAS, Bandar Seri Iskandar, 31750 Tronoh, Perak (Malaysia); Zabidi, Noor Asmawati Mohd, E-mail: noorasmawati-mzabidi@petronas.com.my [Department of Fundamental and Applied Sciences, Universiti Teknologi PETRONAS, Bandar Seri Iskandar, 31750 Tronoh, Perak (Malaysia); Subbarao, Duvvuri, E-mail: duvvuri-subbarao@petronas.com.my [Department of Chemical Engineering, Universiti Teknologi PETRONAS, Bandar Seri Iskandar, 31750 Tronoh, Perak (Malaysia)

2014-10-24

Catalysts were prepared via a wet impregnation method. Different physicochemical properties of the samples were revealed by transmission electron microscope (TEM), temperature programmed reduction (H{sub 2}-TPR) and carbon dioxide desorption (CO{sub 2}-desorption). Fischer-Tropsch reaction (FTS) was carried out in a fixed-bed microreactor at 220°C and 1 atm, with H{sub 2}/CO = 2v/v and space velocity, SV of 12L/g.h for 5 h. Various characterization techniques revealed that there was a stronger interaction between Co and Al{sub 2}O{sub 3} support compared to that of CNTs support. CNTs support increased the reducibility and decreased Co particle size. A significant increase in % CO conversion and FTS reaction rate was observed over CNTs support compared to that of Co/Al{sub 2}O{sub 3}. Co/CNTs resulted in higher C{sub 5+} hydrocarbons selectivity compared to that of Co/Al{sub 2}O{sub 3} catalyst. CNTs are a better support for Co compared to Al{sub 2}O{sub 3}.
Covalent Organic Framework Electrocatalysts for Clean Energy Conversion.

Science.gov (United States)

Lin, Chun-Yu; Zhang, Detao; Zhao, Zhenghang; Xia, Zhenhai

2018-02-01

Covalent organic frameworks (COFs) are promising for catalysis, sensing, gas storage, adsorption, optoelectricity, etc. owning to the unprecedented combination of large surface area, high crystallinity, tunable pore size, and unique molecular architecture. Although COFs are in their initial research stage, progress has been made in the design and synthesis of COF-based electrocatalysis for the oxygen reduction reaction, oxygen evolution reaction, hydrogen evolution reaction, and CO 2 reduction in energy conversion and fuel generation. Design principles are also established for some of the COF materials toward rational design and rapid screening of the best electrocatalysts for a specific application. Herein, the recent advances in the design and synthesis of COF-based catalysts for clean energy conversion and storage are presented. Future research directions and perspectives are also being discussed for the development of efficient COF-based electrocatalysts. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Method of preparing and utilizing a catalyst system for an oxidation process on a gaseous hydrocarbon stream

Science.gov (United States)

Berry, David A; Shekhawat, Dushyant; Smith, Mark; Haynes, Daniel

2013-07-16

The disclosure relates to a method of utilizing a catalyst system for an oxidation process on a gaseous hydrocarbon stream with a mitigation of carbon accumulation. The system is comprised of a catalytically active phase deposited onto an oxygen conducting phase, with or without supplemental support. The catalytically active phase has a specified crystal structure where at least one catalytically active metal is a cation within the crystal structure and coordinated with oxygen atoms within the crystal structure. The catalyst system employs an optimum coverage ratio for a given set of oxidation conditions, based on a specified hydrocarbon conversion and a carbon deposition limit. Specific embodiments of the catalyst system are disclosed.
Jet-Fuel Range Hydrocarbons from Biomass-Derived Sorbitol over Ni-HZSM-5/SBA-15 Catalyst

Directory of Open Access Journals (Sweden)

Yujing Weng

2015-12-01

Full Text Available Aromatics and cyclic-hydrocarbons are the significant components of jet fuel with high energy-density. However, conventional technologies for bio-fuel production cannot produce these products without further aromatization and isomerization. In this work, renewable liquid fuel with high content of aromatics and cyclic-hydrocarbons was obtained through aqueous catalytic conversion of biomass sorbitol over Ni-HZSM-5/SBA-15 catalyst. Texture characteristics of the catalyst were determined by physisorption of N2, which indicated its bimodal pore structures were microporous (HZSM-5, pore width: 0.56 nm and mesoporous (SBA-15, pore width: 8 nm. The surface acidity included weak and strong acid sites, predominantly Lewis type, and was further confirmed by the NH3-TPD and Py-IR analysis. The catalytic performances were tested in a fixed-bed reactor under the conditions of 593 K, WHSV of 0.75 h−1, GHSV of 2500 h−1 and 4.0 MPa of hydrogen pressure, whereby oil yield of 40.4 wt. % with aromatics and cyclic-hydrocarbons content of 80.0% was obtained.
Characterization of hydrocarbons, halocarbons and carbonyls in the atmosphere of Hong Kong.

Science.gov (United States)

Guo, H; Lee, S C; Louie, P K K; Ho, K F

2004-12-01

Ambient air quality measurements of 156 species including 39 alkanes, 32 alkenes, 2 alkynes, 24 aromatic hydrocarbons, 43 halocarbons and 16 carbonyls, were carried out for 120 air samples collected at two sampling stations (CW and TW) in 2001 throughout Hong Kong. Spatial variations of volatile organic compounds (VOCs) in the atmosphere were investigated. Levels of most alkanes and alkenes at TW site were higher than that at the CW site, while the BTEX concentrations at the two sites were close. The BTEX ratios at CW and TW were 1.6:10.1:1.0:1.6 and 2.1:10.8:1.0:2.0, respectively. For major halogenated hydrocarbons, the mean concentrations of chloromethane, CFCs 12 and 22 did not show spatial variations at the two sites. However, site-specific differences were observed for trichloroethene and tetrachloroethene. Furthermore, there were no significant differences for carbonyls such as formaldehyde, acetaldehyde and acetone between the two sites. The levels of selected hydrocarbons in winter were 1-5 times that in summer. There were no common seasonal trends for carbonyls in Hong Kong. The ambient level of formaldehyde, the most abundant carbonyl, was higher in summer. However, levels of acetaldehyde, acetone and benzaldehyde in winter were 1.6-3.8 times that in summer. The levels of CFCs 11 and 12, and chloromethane in summer were higher than that in winter. Strong correlation of most hydrocarbons with propene and n-butane suggested that the primary contributors of hydrocarbons were vehicular emissions in Hong Kong. In addition, gasoline evaporation, use of solvents, leakage of liquefied petroleum gas (LPG), natural gas leakage and other industrial emissions, and even biogenic emissions affected the ambient levels of hydrocarbons. The sources of halocarbons were mainly materials used in industrial processes and as solvents. Correlation analysis suggested that photochemical reactions made significant contributions to the ambient levels of carbonyls in summer whereas
Production of Jet Fuel-Range Hydrocarbons from Hydrodeoxygenation of Lignin over Super Lewis Acid Combined with Metal Catalysts

International Nuclear Information System (INIS)

Wang, Hongliang; Wang, Huamin; Kuhn, Eric; Tucker, Melvin P.; Yang, Bin

2017-01-01

Super Lewis acids containing the triflate anion [e.g., Hf(OTf) 4 , Ln(OTf) 3 , In(OTf) 3 , Al(OTf) 3 ] and noble metal catalysts (e.g., Ru/C, Ru/Al2O 3 ) formed efficient catalytic systems to generate saturated hydrocarbons from lignin in high yields. In such catalytic systems, the metal triflates mediated rapid ether bond cleavage through selective bonding to etheric oxygens while the noble metal catalyzed subsequent hydrodeoxygenation (HDO) reactions. Near theoretical yields of hydrocarbons were produced from lignin model compounds by the combined catalysis of Hf(OTf)4 and ruthenium-based catalysts. When a technical lignin derived from a pilot-scale biorefinery was used, more than 30 wt % of the hydrocarbons produced with this catalytic system were cyclohexane and alkylcyclohexanes in the jet fuel range. Super Lewis acids are postulated to strongly interact with lignin substrates by protonating hydroxyl groups and ether linkages, forming intermediate species that enhance hydrogenation catalysis by supported noble metal catalysts. Meanwhile, the hydrogenation of aromatic rings by the noble metal catalysts can promote oxygenation reactions catalyzed by super Lewis acids.
Production of Jet Fuel-Range Hydrocarbons from Hydrodeoxygenation of Lignin over Super Lewis Acid Combined with Metal Catalysts

Energy Technology Data Exchange (ETDEWEB)

Wang, Hongliang [Department of Biological Systems Engineering, Washington State University, Richland WA 99354 USA; Current address: Center of Biomass Engineering/College of Agronomy and Biotechnology, China Agricultural University, Beijing 100193 PR China; Wang, Huamin [Pacific Northwest National Laboratory, 902 Battelle Boulevard Richland WA 99354 USA; Kuhn, Eric [National Bioenergy Center, National Renewable Energy Laboratory, 15013 Denver West Parkway Golden CO 80401 USA; Tucker, Melvin P. [National Bioenergy Center, National Renewable Energy Laboratory, 15013 Denver West Parkway Golden CO 80401 USA; Yang, Bin [Department of Biological Systems Engineering, Washington State University, Richland WA 99354 USA

2017-11-14

Super Lewis acids containing the triflate anion (e.g. Hf(OTf)4, Ln(OTf)3, Al(OTf)3) and noble metal catalysts (e.g. Ru/C, Ru/Al2O3) formed efficient catalytic systems to generate saturated hydrocarbons from lignin in high yields. In such catalytic systems, the metal triflates mediated rapid ether bond cleavage via selective bonding to etheric oxygens while the noble metal catalysed subsequent hydrodeoxygenation (HDO) reactions. Near theoretical yields of hydrocarbons were produced from lignin model compounds by the combined catalysis of Hf(OTf)4 and ruthenium-based catalysts. When a technical lignin derived from a pilot-scale biorefinery was used, more than 30 wt% of the hydrocarbons produced with this catalytic system were cyclohexane and alkylcyclohexanes in the jet fuel range. Super Lewis acids are postulated to strongly interact with lignin substrates via protonating hydroxyls and ether linkages, forming intermediate species that enhance hydrogenation catalysis by supported noble metal catalysts. Meanwhile, the hydrogenation of aromatic rings by the noble metal catalysts can promote oxygenation reactions catalysed by super Lewis acids.
A simple one-step chemistry model for partially premixed hydrocarbon combustion

Energy Technology Data Exchange (ETDEWEB)

Fernandez-Tarrazo, Eduardo [Instituto Nacional de Tecnica Aeroespacial, Madrid (Spain); Sanchez, Antonio L. [Area de Mecanica de Fluidos, Universidad Carlos III de Madrid, Leganes 28911 (Spain); Linan, Amable [ETSI Aeronauticos, Pl. Cardenal Cisneros 3, Madrid 28040 (Spain); Williams, Forman A. [Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, CA 92093-0411 (United States)

2006-10-15

This work explores the applicability of one-step irreversible Arrhenius kinetics with unity reaction order to the numerical description of partially premixed hydrocarbon combustion. Computations of planar premixed flames are used in the selection of the three model parameters: the heat of reaction q, the activation temperature T{sub a}, and the preexponential factor B. It is seen that changes in q with equivalence ratio f need to be introduced in fuel-rich combustion to describe the effect of partial fuel oxidation on the amount of heat released, leading to a universal linear variation q(f) for f>1 for all hydrocarbons. The model also employs a variable activation temperature T{sub a}(f) to mimic changes in the underlying chemistry in rich and very lean flames. The resulting chemistry description is able to reproduce propagation velocities of diluted and undiluted flames accurately over the whole flammability limit. Furthermore, computations of methane-air counterflow diffusion flames are used to test the proposed chemistry under nonpremixed conditions. The model not only predicts the critical strain rate at extinction accurately but also gives near-extinction flames with oxygen leakage, thereby overcoming known predictive limitations of one-step Arrhenius kinetics. (author)
A review of catalytic aqueous-phase reforming of oxygenated hydrocarbons derived from biorefinery water fractions

NARCIS (Netherlands)

Coronado, I.; Stekrova, M.; Reinikainen, M.; Simell, P.; Lefferts, Leonardus; Lehtonen, J.

2016-01-01

Aqueous-phase reforming (APR) of oxygenated hydrocarbons is a process for the production of hydrogen and light alkanes. The reactants of APR remain in liquid phase during the reaction avoiding an energetically demanding vaporization-step compared to processes such as steam reforming (SR).
Thermal Characteristics of Conversion-Type FeOF Cathode in Li-ion Batteries

Directory of Open Access Journals (Sweden)

Liwei Zhao

2017-10-01

Full Text Available Rutile FeOF was used as a conversion-type cathode material for Li-ion batteries. In the present study, 0.6Li, 1.4Li, and 2.7Li per mole lithiation reactions were carried out by changing the electrochemical discharge reaction depth. The thermal characteristics of the FeOF cathode were investigated by thermogravimetric mass spectrometric (TG-MS and differential scanning calorimeter (DSC systems. No remarkable HF release was detected, even up to 700 °C, which indicated a low toxic risk for the FeOF cathode. Changes in the thermal properties of the FeOF cathode via different conversion reaction depths in the associated electrolyte were studied by changing the cathode/electrolyte ratio in the mixture. LiFeOF was found to exothermically react with the electrolyte at about 210 °C. Similar exothermic reactions were found with charged FeOF cathodes because of the irreversible Li ions. Among the products of the conversion reaction of FeOF, Li2O was found to exothermically react with the electrolyte at about 120 °C, which induced the main thermal risk of the FeOF cathode. It suggests that the oxygen-containing conversion-type cathodes have a higher thermal risk than the oxygen-free ones, but controlling the cathode/electrolyte ratio in cells successfully reduced the thermal risk. Finally, the thermal stability of the FeOF cathode was evaluated in comparison with FeF3 and LiFePO4 cathodes.
A chemical and thermodynamic model of oil generation in hydrocarbon source rocks

Science.gov (United States)

Helgeson, Harold C.; Richard, Laurent; McKenzie, William F.; Norton, Denis L.; Schmitt, Alexandra

2009-02-01

Thermodynamic calculations and Gibbs free energy minimization computer experiments strongly support the hypothesis that kerogen maturation and oil generation are inevitable consequences of oxidation/reduction disproportionation reactions caused by prograde metamorphism of hydrocarbon source rocks with increasing depth of burial.These experiments indicate that oxygen and hydrogen are conserved in the process.Accordingly, if water is stable and present in the source rock at temperatures ≳25 but ≲100 °C along a typical US Gulf Coast geotherm, immature (reduced) kerogen with a given atomic hydrogen to carbon ratio (H/C) melts incongruently with increasing temperature and depth of burial to produce a metastable equilibrium phase assemblage consisting of naphthenic/biomarker-rich crude oil, a type-II/III kerogen with an atomic hydrogen/carbon ratio (H/C) of ˜1, and water. Hence, this incongruent melting process promotes diagenetic reaction of detritus in the source rock to form authigenic mineral assemblages.However, in the water-absent region of the system CHO (which is extensive), any water initially present or subsequently entering the source rock is consumed by reaction with the most mature kerogen with the lowest H/C it encounters to form CO 2 gas and a new kerogen with higher H/C and O/C, both of which are in metastable equilibrium with one another.This hydrolytic disproportionation process progressively increases both the concentration of the solute in the aqueous phase, and the oil generation potential of the source rock; i.e., the new kerogen can then produce more crude oil.Petroleum is generated with increasing temperature and depth of burial of hydrocarbon source rocks in which water is not stable in the system CHO by a series of irreversible disproportionation reactions in which kerogens with higher (H/C)s melt incongruently to produce metastable equilibrium assemblages consisting of crude oil, CO 2 gas, and a more mature (oxidized) kerogen with a lower
Reaction of a (Salen)ruthenium(VI) nitrido complex with thiols. C-H bond activation by (Salen)ruthenium(IV) sulfilamido species.

Science.gov (United States)

Man, Wai-Lun; Lam, William W Y; Kwong, Hoi-Ki; Peng, Shie-Ming; Wong, Wing-Tak; Lau, Tai-Chu

2010-01-04

The reaction of [Ru(VI)(N)(L)(MeOH)](PF(6)) [1; L = N,N'-bis(salicylidene)-o-cyclohexyldiamine dianion] with a stoichiometric amount of RSH in CH(3)CN gives the corresponding (salen)ruthenium(IV) sulfilamido species [Ru(IV){N(H)SR}(L)(NCCH(3))](PF(6)) (2a, R = (t)Bu; 2b, R = Ph). Metathesis of 2a with NaN(3) in methanol affords [Ru(IV){N(H)S(t)Bu}(L)(N(3))] (2c). 2a undergoes further reaction with 1 equiv of RSH to afford a (salen)ruthenium(III) sulfilamine species, [Ru(III){N(H)(2)S(t)Bu}(L)(NCCH(3))](PF(6)) (3). On the other hand, 2b reacts with 2 equiv of PhSH to give a (salen)ruthenium(III) ammine species [Ru(III)(NH(3))(L)(NCCH(3))](PF(6)) (4); this species can also be prepared by treatment of 1 with 3 equiv of PhSH. The X-ray structures of 2c and 4 have been determined. Kinetic studies of the reaction of 1 with excess RSH indicate the following schemes: 1 --> 2a --> 3 (R = (t)Bu), 1 --> 2b --> 4 (R = Ph). The conversion of 1 to 2 probably involves nucleophilic attack of RSH at the nitrido ligand, followed by a proton shift. The conversions of 2a to 3 and 2b to 4 are proposed to involve rate-limiting H-atom abstraction from RSH by 2a or 2b. 2a and 2b are also able to abstract H atoms from hydrocarbons with weak C-H bonds. These reactions occur with large deuterium isotope effects; the kinetic isotope effect values for the oxidation of 9,10-dihydroanthracene, 1,4-cyclohexadiene, and fluorene by 2a are 51, 56, and 11, respectively.
Hydrogen production by reforming of hydrocarbons and alcohols in a dielectric barrier discharge

Energy Technology Data Exchange (ETDEWEB)

Sarmiento, Belen; Brey, J. Javier; Viera, Inmaculada G. [Hynergreen Technologies, S.A. Avda. de la Buhaira, 2. 41018 Sevilla (Spain); Gonzalez-Elipe, Agustin R.; Cotrino, Jose; Rico, Victor J. [Instituto de Ciencia de los Materiales de Sevilla (CSIC-University Sevilla), Avda. Americo Vespucio, 49, 41092 Sevilla (Spain)

2007-06-10

This work reports about the use of plasmas to obtain hydrogen by reforming of hydrocarbons or alcohols in mixtures with CO{sub 2} or H{sub 2}O. The plasma is activated in a dielectric barrier discharge (DBD) reactor working at atmospheric pressure and low temperatures (i.e., about 100 C). The reactor presents a great versatility in operation and a low manufacturing cost. Results are presented for the reforming of methane, methanol and ethanol. Methane transforms up to a 70% into CO and H{sub 2} without formation of any kind of superior hydrocarbon. For the two alcohols 100% conversion into the same products is found for flows much higher than in the case of methane. The work reports a description of the reactor and the operational conditions of the power supply enabling the ignition of the plasma and its steady state operation. (author)
Towards comprehensive hydrocarbons analysis of middle distillates by LC-GCxGC.

Science.gov (United States)

Adam, Frédérick; Bertoncini, Fabrice; Thiébaut, Didier; Esnault, Sébastien; Espinat, Didier; Hennion, M C

2007-01-01

The detailed characterization of middle distillates is essential for a better understanding of reactions involved in refining processes. Owing to a higher resolution power and an enhanced sensitivity, but especially to a group-type ordering in the chromatographic plane, comprehensive two-dimensional gas chromatography (GCxGC) offers unsurpassed characterization possibilities for petroleum samples. However, GCxGC fails to totally discriminate naphthenes from unsaturates occurring in hydrotreated diesel samples. This article aims at promoting the implementation of LC-GCxGC for the quantitative determination of hydrocarbon distribution in middle distillates, including naphthenes. In this configuration, liquid chromatography (LC) enables the separation of hydrocarbons into two fractions (viz., saturated and unsaturated) before the subsequent analysis of each fraction by GCxGC. In this paper, the choice of GCxGC conditions in order to achieve the separation and identification of hydrocarbons by chemical class is discussed; under these conditions, naphthenes are separated according to the number of saturated rings. For the first time, the presence of di-, tri-, and tetra-naphthenes resulting from the hydroconversion of aromatics can clearly be evidenced. A quantitative procedure for the determination of the distribution of hydrocarbons, including the distribution of naphthenes according to the number of saturated rings, is also proposed and discussed in detail. LC-GCxGC is found to provide an unequalled degree of information that will widely contribute to a better understanding of hydroconversion processes.
Pyrolytic conversion of plastic and rubber waste to hydrocarbons with basic salt catalysts

Science.gov (United States)

Wingfield, Jr., Robert C.; Braslaw, Jacob; Gealer, Roy L.

1985-01-01

The invention relates to a process for improving the pyrolytic conversion of waste selected from rubber and plastic to low molecular weight olefinic materials by employing basis salt catalysts in the waste mixture. The salts comprise alkali or alkaline earth compounds, particularly sodium carbonate, in an amount of greater than about 1 weight percent based on the waste feed.
Plasma devices for hydrocarbon reformation

KAUST Repository

Cha, Min

2017-01-01

Plasma devices for hydrocarbon reformation are provided. Methods of using the devices for hydrocarbon reformation are also provided. The devices can include a liquid container to receive a hydrocarbon source, and a plasma torch configured
Zeolite synthesis from the pyrrolidine containing system and their catalytic properties in the methanol conversion reaction

Energy Technology Data Exchange (ETDEWEB)

Suzuki, Kunio; Kiyozumi, Yoshimichi; Shin, Shigemitsu; Ogawa, Kiyoshi; Yamazaki, Yasuyoshi; Watanabe, Hideo

1987-12-18

Systhesis of zeolite from a system containing cheaper pyrrolidine as a crystallization regulator than quaternary ammonium ion was carried out and the methanol conversion reaction was studied over the systhesized zeolite to get C/sub 2/ and C/sub 3/ olefins. Hydrous gels were prepared by adding and agitating pyrrolidine, water glass and sulfuric acid to aluminum sulfate solution; and aluminum nitrate, colloidal silica and pyrrolidine to NaOH solution. Five zeolite, that is, ZSM-5, ZSM-35, ZSM-39, ZSM-48 and KZ-1 were synthesized by changing gel components. X-ray powder diffraction, BET specific surface areas, micropore diameters, micropore volumes, oxygen contents by scanning electron photomicrographs and infra-red spectra were examined. The organic base in hydrous gels influenced greatly on the zeolite composition and structure. The ZSM-5 zeolite exhibited the superior performance as to a high selectivity of light olefins over the target of development. (12 figs, 1 tab, 20 refs)
11C-radioisotope study of methanol co-reaction with ethanol over Ni-MCM-41 silica-alumina and Ni-alumina

International Nuclear Information System (INIS)

Sarkadi-Priboczki, E.; Kovacs, Z.; Tsoncheva, T.; Kumar, N.; Murzin, D.Yu.

2009-01-01

, appears beside 11 C-dimethyl ether considerably on H-MCM-41 while slighter on Ni-alumina and Ni-MCM-41 in favor of methane. The 11 C-labeled carbon dioxide and formaldehyde were also radiodetected on Ni-alumina and Ni- MCM-41 silica-alumina between 240-350 degC but with variant ratios compared to single methanol transformation. The selectivities of non-radioactive ethanol to hydrocarbons as well as 11 C-methyl ethyl co-ether transformation to 11 C-hydrocarbons were different along H-MCM-41, Ni-MCM-41 and Ni-Al 2 O 3 . The ethanol formed to hydrocarbons on all of catalysts and acetaldehyde was also detected on Ni-Al 2 O 3 and on Ni-MCM-41. Conclusion Methanol conversion over H-MCM-41, Ni-MCM-41 and Ni/Al 2 O 3 could be significantly changed in the presence of ethanol as a coreactant. At lower temperature, formation of methyl ethyl co-ether is observed, while with the temperature increase its conversion to methane and C 2 -C 5 hydrocarbons becomes the main reaction pathway.
Solar energy conversion. Chemical aspects

Energy Technology Data Exchange (ETDEWEB)

Likhtenshtein, Gertz [Ben-Gurion Univ. of the Negev, Beersheba (Israel). Dept. of Chemistry

2012-07-01

Finally filling a gap in the literature for a text that also adopts the chemist's view of this hot topic, Professor Likhtenshtein, an experienced author and internationally renowned scientist, considers different physical and engineering aspects in solar energy conversion. From theory to real-life systems, he shows exactly which chemical reactions take place when converting light energy, providing an overview of the chemical perspective from fundamentals to molecular harvesting systems and solar cells. This essential guide will thus help researchers in academia and industry better understand solar energy conversion, and so ultimately help this promising, multibillion euro/dollar field to expand. (orig.)
The direct conversion of synthesis gas to chemicals / Ernest du Toit

OpenAIRE

Du Toit, Ernest

2002-01-01

The catalytic conversion of synthesis gas, obtainable from the processing of coal, biomass or natural gas, to a complex hydrocarbon product stream can be achieved via the Fischer-Tropsch process. The Fischer-Tropsch synthesis process has evolved from being mainly a fuel producing process in the early 1950's to that of a solvent and speciality wax production process towards the end of the 1970's. From the early 1980's there has been a clear shift towards the production of commod...
Reactions of charged and neutral recoil particles following nuclear transformations. Progress report No. 13

International Nuclear Information System (INIS)

Ache, H.J.

1979-09-01

Research is reported on: caging and solvent effects in hot 38 Cl substitution reactions in chlorinated hydrocarbons (dichlorobenzene), excitation labelling of organic compounds using 80 Br, reactions of energetic tritium with graphite and SiC surfaces, and micellar systems and microemulsions studied by positron annihilation
High Zn/Al ratios enhance dehydrogenation vs hydrogen transfer reactions of Zn-ZSM-5 catalytic systems in methanol conversion to aromatics

DEFF Research Database (Denmark)

Pinilla-Herrero, Irene; Borfecchia, Elisa; Holzinger, Julian

2018-01-01

suggest that catalytic activity is associated with [Zn(H2O)n(OH)]+ species located in the exchange positions of the materials with little or no contribution of ZnO or metallic Zn. The effect of Zn/Al ratio on their catalytic performance in methanol conversion to aromatics has been investigated. In all...... cases, higher Zn content causes an increase in the yield of aromatics while keeping the production of alkanes low. For similar Zn contents, high densities of Al sites favour the hydrogen transfer reactions and alkane formation whereas in samples with low Al contents, and thus higher Zn/Al ratio...

Analysing destruction channels of interstellar hydrocarbon anions with a 22pol ion-trap

Energy Technology Data Exchange (ETDEWEB)

Endres, Eric; Lakhmanskaya, Olga; Best, Thorsten; Hauser, Daniel; Kumar, Sunil; Wester, Roland [Universitaet Innsbruck, Institut fuer Ionenphysik und Angewandte Physik (Austria)

2014-07-01

In the interstellar medium (ISM), ion-molecule reactions are considered to play a key role in the formation of complex molecules. The detection of the first interstellar anions, which happen to be carbon chain anions, has raised new interest in the quantitative composition of the ISM and the underlying reaction network. To understand the observed abundance of these carbon chain anions, a detailed analysis of the possible destruction channels is indispensable. A cryogenic 22-pol radio frequency ion trap is an ideal tool to observe reactions that take place slowly, such as carbon chain anions with molecular hydrogen. Furthermore, measurements over a large temperature scale are feasible. Longitudinal optical access to the trap also provides the possibility to make precise photodetachment measurements. Temperature dependent measurements of the reaction rates for the reaction between hydrocarbon chain anions and H{sub 2} are presented.
Reactions of model compounds in the presence of pyrene and MoS sub 2 to simulate coprocessing

Energy Technology Data Exchange (ETDEWEB)

Ting, P.-S.; Curtis, C.W.; Cronauer, D.C. (Auburn University, Auburn, AL (USA). Chemical Engineering Dept.)

Catalytic reactions of pyrene using in situ generated MoS{sub 2} from molybdenum naphthenate and excess sulfur were evaluated in the presence of added model species, both hydrocarbons and heteroatomic species. The added hydrocarbons and heteroatomic compounds containing oxygen and sulfur had little effect on the hydrogenation of pyrene at either 400 or 425{degree}C, but quinoline at 400{degree}C reduced the hydrogenation of pyrene by half. Reactions at 425{degree}C also reduced the hydrogenation of pyrene by half regardless of the added model species. The added model species underwent different degrees of reaction: the hydrocarbons underwent little or no reaction, dibenzofuran showed little hydrodeoxygenation, dibenzothiophene yielded substantial hydrodesulfurization and quinoline was almost totally hydrodenitrogenated. The addition of quinoline at increasing concentration resulted in substantial lowering of pyrene hydrogenation and quinoline hydrodenitrogenation. Introduction of quinoline at a low concentration of 0.4 wt% gave a pyrene hydrogenation rate constant of 0.073 min{sup -1} at 400{degree}C while an increase in quinoline to 10.0 wt% yielded a rate constant of 0.020 min{sup -1}. 21 refs., 7 figs., 6 tabs.
Specific biases for identifying facial expression of emotion in children and adolescents with conversion disorders.

Science.gov (United States)

Kozlowska, Kasia; Brown, Kerri J; Palmer, Donna M; Williams, Lea M

2013-04-01

This study aimed to assess how children and adolescents with conversion disorders identify universal facial expressions of emotion and to determine whether identification of emotion in faces relates to subjective emotional distress. Fifty-seven participants (41 girls and 16 boys) aged 8.5 to 18 years with conversion disorders and 57 age- and sex-matched healthy controls completed a computerized task in which their accuracy and reaction times for identifying facial expressions were recorded. To isolate the effect of individual emotional expressions, participants' reaction times for each emotion (fear, anger, sadness, disgust, and happiness) were subtracted from their reaction times for the neutral control face. Participants also completed self-report measures of subjective emotional distress. Children/Adolescents with conversion disorders showed faster reaction times for identifying expressions of sadness (t(112) = -2.2, p = .03; 444 [609] versus 713 [695], p = .03) and slower reactions times for happy expressions (t(99.3) = 2.28, p ≤ .024; -33 [35] versus 174 [51], p = .024), compared with controls (F(33.75, 419.81) = 3.76, p .018). There were also no differences in identification accuracy for any emotion (p > .82). The observation of faster reaction times to sad faces in children and adolescents with conversion disorders suggests increased vigilance and motor readiness to emotional signals that are potential threats to self or to close others. These effects may occur before conscious processing.
Reaction kinetics for preparation of silica film with Stoeber method

International Nuclear Information System (INIS)

Shang Mengying; Jiang Xiaodong; Liu Miao; Luo Xuan; Tang Yongjian; Cao Linhong

2013-01-01

A new formula was proposed to investigate the relationship between reaction time and tetraethylorthosilicate (TEOS) conversion rate for preparation of silica sol with Stöber method, by studying the reaction kinetics of TEOS hydrolytic process. An appropriate conversion rate was then determined and used to calculate the theoretical optimal reaction time. Meanwhile, silica sols were prepared by sol-gel process using TEOS as precursor and ammonia as catalyst. It was found that the reaction time decreases with an increasing amount of ammonia and water. The values of experimental optimal reaction time were obtained, and agree with the theoretical results (the errors are within 5%), which shows good applicability of our formula. (authors)
The Non-Ergodic Nature of Internal Conversion

DEFF Research Database (Denmark)

Sølling, Theis I.; Kuhlman, Thomas Scheby; Stephansen, Anne B.

2014-01-01

The absorption of light by molecules can induce ultrafast dynamics and coupling of electronic and nuclear vibrational motion. The ultrafast nature in many cases rests on the importance of several potential energy surfaces in guiding the nuclear motion—a concept of central importance in many aspects...... of chemical reaction dynamics. This Minireview focuses on the non-ergodic nature of internal conversion, that is, on the concept that the nuclear dynamics only sample a reduced phase space, potentially resulting in localization of the dynamics in real space. A series of results that highlight...... it takes to reach it. 2) Localization of energy into a single reactive mode, which is dictated by the internal conversion process. 3) Initiation of the internal conversion by activation of a single complex motion, which then specifically couples to a reactive mode. 4) Nonstatistical internal conversion...
Molecular networks in Position, Momentum, and Phase Space: A Case Study on Simple Hydrocarbons

DEFF Research Database (Denmark)

Schmider, Hartmut; Ho, Minhhuy

1996-01-01

are identified in a series of nine small hydrocarbonic molecules, and the resulting "molecular graphs" are interpreted in terms of symmetry and topology. For the example of a symmetric SN2 reaction, it is shown that the topology of the Husimi function based graphs can be useful for the classification of chemical...
Catalysis of Nuclear Reactions by Electrons

Science.gov (United States)

Lipoglavšek, Matej

2018-01-01

Electron screening enhances nuclear reaction cross sections at low energies. We studied the nuclear reaction 1H(19F,αγ)16O in inverse kinematics in different solid hydrogen targets. Measured resonance strengths differed by up to a factor of 10 in different targets. We also studied the 2H(p,γ)3He fusion reaction and observed electrons emitted as reaction products instead of γ rays. In this case electron screening greatly enhances internal conversion probability.
First-principles quantum-mechanical investigations: The role of water in catalytic conversion of furfural on Pd(111)

Science.gov (United States)

Xue, Wenhua; Borja, Miguel Gonzalez; Resasco, Daniel E.; Wang, Sanwu

2015-03-01

In the study of catalytic reactions of biomass, furfural conversion over metal catalysts with the presence of water has attracted wide attention. Recent experiments showed that the proportion of alcohol product from catalytic reactions of furfural conversion with palladium in the presence of water is significantly increased, when compared with other solvent including dioxane, decalin, and ethanol. We investigated the microscopic mechanism of the reactions based on first-principles quantum-mechanical calculations. We particularly identified the important role of water and the liquid/solid interface in furfural conversion. Our results provide atomic-scale details for the catalytic reactions. Supported by DOE (DE-SC0004600). This research used the supercomputer resources at NERSC, of XSEDE, at TACC, and at the Tandy Supercomputing Center.
Detection of hydrocarbons in irradiated foods

International Nuclear Information System (INIS)

Miyahara, Makoto; Maitani, Tamio; Saito, Akiko; Kamimura, Tomomi; Nagasawa, Taeko; Kobayashi, Yasuo; Ito, Hitoshi

2003-01-01

The hydrocarbon method for the detection of irradiated foods is now recognized as the international technique. This method is based on radiolysis of fatty acids in food to give hydrocarbons. In order to expand this technique's application, ten foods (butter, cheese, chicken, pork, beef, tuna, dry shrimp, avocado, papaya, and mango) were irradiated in the range from 0.5 to 10 kGy and the hydrocarbons in them were detected. Recoveries of the hydrocarbons from most foods were acceptable (38-128%). Some hydrocarbons were found in non-irradiated foods, particularly, in butter, cheese, tuna, and shrimp. Seven irradiated foods, butter, cheese, chicken, beef, pork, tuna, dry shrimp, and avocado were detectable at their practical doses by measuring the appropriate marker hydrocarbons. In most case, marker hydrocarbon will be 1,7-hexadecadiene. However, the marker hydrocarbons produced only in irradiated foods varied from food to food; therefore, it is necessary to check a specific irradiated food for marker hydrocarbons. On the other hand, two irradiated foods (papaya and mango which were irradiated at their practical doses) were difficult to distinguish from non-irradiated foods using this method. (author)
Detection of hydrocarbons in irradiated foods

Energy Technology Data Exchange (ETDEWEB)

Miyahara, Makoto; Maitani, Tamio [National Inst. of Health Sciences, Tokyo (Japan); Saito, Akiko; Kamimura, Tomomi; Nagasawa, Taeko [Kitasato Univ., Sagamihara, Kanagawa (Japan). School of Allied Health Sciences; Kobayashi, Yasuo; Ito, Hitoshi [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Establishment

2003-06-01

The hydrocarbon method for the detection of irradiated foods is now recognized as the international technique. This method is based on radiolysis of fatty acids in food to give hydrocarbons. In order to expand this technique's application, ten foods (butter, cheese, chicken, pork, beef, tuna, dry shrimp, avocado, papaya, and mango) were irradiated in the range from 0.5 to 10 kGy and the hydrocarbons in them were detected. Recoveries of the hydrocarbons from most foods were acceptable (38-128%). Some hydrocarbons were found in non-irradiated foods, particularly, in butter, cheese, tuna, and shrimp. Seven irradiated foods, butter, cheese, chicken, beef, pork, tuna, dry shrimp, and avocado were detectable at their practical doses by measuring the appropriate marker hydrocarbons. In most case, marker hydrocarbon will be 1,7-hexadecadiene. However, the marker hydrocarbons produced only in irradiated foods varied from food to food; therefore, it is necessary to check a specific irradiated food for marker hydrocarbons. On the other hand, two irradiated foods (papaya and mango which were irradiated at their practical doses) were difficult to distinguish from non-irradiated foods using this method. (author)
Pretreated Landfill Gas Conversion Process via a Catalytic Membrane Reactor for Renewable Combined Fuel Cell-Power Generation

Directory of Open Access Journals (Sweden)

Zoe Ziaka

2013-01-01

Full Text Available A new landfill gas-based reforming catalytic processing system for the conversion of gaseous hydrocarbons, such as incoming methane to hydrogen and carbon oxide mixtures, is described and analyzed. The exit synthesis gas (syn-gas is fed to power effectively high-temperature fuel cells such as SOFC types for combined efficient electricity generation. The current research work is also referred on the description and design aspects of permreactors (permeable reformers carrying the same type of landfill gas-reforming reactions. Membrane reactors is a new technology that can be applied efficiently in such systems. Membrane reactors seem to perform better than the nonmembrane traditional reactors. The aim of this research includes turnkey system and process development for the landfill-based power generation and fuel cell industries. Also, a discussion of the efficient utilization of landfill and waste type resources for combined green-type/renewable power generation with increased processing capacity and efficiency via fuel cell systems is taking place. Moreover, pollution reduction is an additional design consideration in the current catalytic processors fuel cell cycles.
Problems Caused by Microbes and Treatment Strategies Anaerobic Hydrocarbon Biodegradation and Biocorrosion: A Case Study

Science.gov (United States)

Suflita, Joseph M.; Duncan, Kathleen E.

The anaerobic biodegradation of petroleum hydrocarbons is important for the intrinsic remediation of spilt fuels (Gieg and Suflita, 2005), for the conversion of hydrocarbons to clean burning natural gas (Gieg et al., 2008; Jones et al., 2008) and for the fundamental cycling of carbon on the planet (Caldwell et al., 2008). However, the same process has also been implicated in a host of difficult problems including reservoir souring (Jack and Westlake, 1995), oil viscosity alteration (Head et al., 2003), compromised equipment performance and microbiologically influenced corrosion (Duncan et al., 2009). Herein, we will focus on the role of anaerobic microbial communities in catalysing biocorrosion activities in oilfield facilities. Biocorrosion is a costly problem that remains relatively poorly understood. Understanding of the underlying mechanisms requires reliable information on the carbon and energy sources supporting biofilm microorganisms capable of catalysing such activities.
Enzymatic Upgrading of Heavy Crudes via Partial Oxidation or Conversion of PAHs

Energy Technology Data Exchange (ETDEWEB)

Borole, A P; Davison, B H; Kuritz, T

2002-07-01

The objective of this program was to investigate new enzyme-based technologies for upgrading of heavy oils. Enzymes were selected for screening from those capable of conversion of polyaromatic hydrocarbons (PAHs) reported in the literature. Oxidative reactions of PAHs using hydrogen peroxide as an oxidant with conversion to partially oxidized products were used. The enzymes (lignin peroxidase, cytochrome c) were tested in various organic solvents and found to loose activity in pure organic solvents. A thermodynamic analysis revealed lack of effective interaction between the substrate and enzyme as the cause for low activity. The protein cytochrome c was modified to work in organic media by chemical hydrophobic group attachment. Two different modifications were made: attachment of polyethylene glycol (PEG) and alkyl groups. Alkyl groups, being small could be attached at interior locations within the core of the enzyme and possibly near the active site. Increase in the threshold solvent concentration where maximum enzyme activity occurred indicated potential of this strategy for effective enzyme-substrate interaction. Further improvements in enzyme activity called for other diverse methods due to the unavailability of sufficient chemical modification sites. Genetic techniques were therefore explored for further improvements. These experiments focused on cloning of a gene for the fungal enzyme lignin peroxidase (lip) into yeast Pichia pastoris, which would allow easy manipulation of the gene. However, differences in the fungal and yeast cellular machinery impeded significant expression of the fungal enzyme. Several strategies were explored to allow higher-level expression of the enzyme, which was required for enzyme improvement. The strategies used in this investigation are described in the report. Industrial in-kind support was available throughout the project period. review of the research results was carried out on a regular basis (bimonthly reports and annual
Tolerance of Antarctic soil fungi to hydrocarbons

Energy Technology Data Exchange (ETDEWEB)

Hughes, Kevin A.; Bridge, Paul; Clark, Melody S. [British Antarctic Survey, Natural Environment Research Council, High Cross, Madingley Road, Cambridge CB3 0ET (United Kingdom)

2007-01-01

Little is known about the effects of hydrocarbons and fuel oil on Antarctic filamentous fungi in the terrestrial Antarctic environment. Growth of fungi and bacteria from soils around Rothera Research Station (Adelaide Island, Antarctic Peninsula) was assessed in the presence of ten separate aromatic and aliphatic hydrocarbons [marine gas oil (MGO), dodecane, hexadecane, benzoic acid, p-hydroxybenzoic acid, toluene, phenol, biphenyl, naphthalene and m- and p-xylenes with ethylbenzene]. Aromatic hydrocarbons inhibited soil microbial growth more than aliphatic hydrocarbons. Soil microorganisms from a moss patch, where little previous impact or hydrocarbon contamination had occurred, were less tolerant of hydrocarbons than those from high impact sites. Fungal growth rates of Mollisia sp., Penicillium commune, Mortierella sp., Trichoderma koningii, Trichoderma sp. and Phoma herbarum were assessed in the presence of hydrocarbons. Generally, aromatic hydrocarbons inhibited or stopped hyphal extension, though growth rates increased with some aliphatic hydrocarbons. Hyphal dry weight measurements suggested that Mortierella sp. may be able to use dodecane as sole carbon and energy source. Hydrocarbon-degrading Antarctic fungi may have use in future hydrocarbon spill bioremediation. (author)
Methanol conversion to light olefins over nanostructured CeAPSO-34 catalyst: Thermodynamic analysis of overall reactions and effect of template type on catalytic properties and performance

Energy Technology Data Exchange (ETDEWEB)

Aghamohammadi, Sogand [Chemical Engineering Faculty, Sahand University of Technology, P.O. Box 51335-1996, Sahand New Town, Tabriz (Iran, Islamic Republic of); Reactor and Catalysis Research Center (RCRC), Sahand University of Technology, P.O. Box 51335-1996, Sahand New Town, Tabriz (Iran, Islamic Republic of); Haghighi, Mohammad, E-mail: haghighi@sut.ac.ir [Chemical Engineering Faculty, Sahand University of Technology, P.O. Box 51335-1996, Sahand New Town, Tabriz (Iran, Islamic Republic of); Reactor and Catalysis Research Center (RCRC), Sahand University of Technology, P.O. Box 51335-1996, Sahand New Town, Tabriz (Iran, Islamic Republic of); Charghand, Mojtaba [Chemical Engineering Faculty, Sahand University of Technology, P.O. Box 51335-1996, Sahand New Town, Tabriz (Iran, Islamic Republic of); Reactor and Catalysis Research Center (RCRC), Sahand University of Technology, P.O. Box 51335-1996, Sahand New Town, Tabriz (Iran, Islamic Republic of)

2014-02-01

Graphical abstract: In this research nanostructured CeAPSO-34 was synthesized to explore the effect of TEAOH and morpholine on its physiochemical properties and MTO performance. Prepared catalysts were characterized with XRD, FESEM, BET, FTIR and NH3-TPD techniques. The results indicated that the nature of the template determines the physiochemical properties of CeAPSO-34 due to different rate of crystal growth. The catalyst obtained by using morpholine showed longer life time as well as sustaining light olefins selectivity at higher values. Furthermore, a comprehensive thermodynamic analysis of overall reactions network was carried out to address the major channels of methanol to olefins conversion. - Highlights: • Introduction of Ce into SAPO-34 framework. • Comparison of CeAPSO-34 synthesized using morpholine and TEAOH. • The nature of the template determines the physiochemical properties of CeAPSO-34. • Morpholine enhances catalyst lifetime in MTO process. • Presenting a complete reaction network for MTO process. - Abstract: TEAOH and morpholine were employed in synthesis of nanostructured CeAPSO-34 molecular sieve and used in methanol to olefins conversion. Prepared samples were characterized by XRD, FESEM, EDX, BET, FTIR and NH{sub 3}-TPD techniques. XRD patterns reflected the higher crystallinity of the catalyst synthesized with morpholine. The FESEM results indicated that the nature of the template determines the morphology of nanostructured CeAPSO-34 due to different rate of crystal growth. There was a meaningful difference in the strength of both strong and weak acid sites for CeAPSO-34 catalysts synthesized with TEAOH and morpholine templates. The catalyst synthesized with morpholine showed higher desorption temperature of both weak and strong acid sites evidenced by NH{sub 3}-TPD characterization. The catalyst obtained using morpholine template had the longer lifetime and sustained desired light olefins at higher values. A comprehensive
Methanol conversion to light olefins over nanostructured CeAPSO-34 catalyst: Thermodynamic analysis of overall reactions and effect of template type on catalytic properties and performance

International Nuclear Information System (INIS)

Aghamohammadi, Sogand; Haghighi, Mohammad; Charghand, Mojtaba

2014-01-01

Graphical abstract: In this research nanostructured CeAPSO-34 was synthesized to explore the effect of TEAOH and morpholine on its physiochemical properties and MTO performance. Prepared catalysts were characterized with XRD, FESEM, BET, FTIR and NH3-TPD techniques. The results indicated that the nature of the template determines the physiochemical properties of CeAPSO-34 due to different rate of crystal growth. The catalyst obtained by using morpholine showed longer life time as well as sustaining light olefins selectivity at higher values. Furthermore, a comprehensive thermodynamic analysis of overall reactions network was carried out to address the major channels of methanol to olefins conversion. - Highlights: • Introduction of Ce into SAPO-34 framework. • Comparison of CeAPSO-34 synthesized using morpholine and TEAOH. • The nature of the template determines the physiochemical properties of CeAPSO-34. • Morpholine enhances catalyst lifetime in MTO process. • Presenting a complete reaction network for MTO process. - Abstract: TEAOH and morpholine were employed in synthesis of nanostructured CeAPSO-34 molecular sieve and used in methanol to olefins conversion. Prepared samples were characterized by XRD, FESEM, EDX, BET, FTIR and NH 3 -TPD techniques. XRD patterns reflected the higher crystallinity of the catalyst synthesized with morpholine. The FESEM results indicated that the nature of the template determines the morphology of nanostructured CeAPSO-34 due to different rate of crystal growth. There was a meaningful difference in the strength of both strong and weak acid sites for CeAPSO-34 catalysts synthesized with TEAOH and morpholine templates. The catalyst synthesized with morpholine showed higher desorption temperature of both weak and strong acid sites evidenced by NH 3 -TPD characterization. The catalyst obtained using morpholine template had the longer lifetime and sustained desired light olefins at higher values. A comprehensive thermodynamic
A thermogravimetric analysis (TGA) method to determine the catalytic conversion of cellulose from carbon-supported hydrogenolysis process

International Nuclear Information System (INIS)

Leal, Glauco F.; Ramos, Luiz A.; Barrett, Dean H.; Curvelo, Antonio Aprígio S.; Rodella, Cristiane B.

2015-01-01

Graphical abstract: - Highlights: • A new method to determine the catalytic conversion of cellulose using TGA has been developed. • TGA is able to differentiate between carbon from cellulose and carbon from the catalyst. • Building an analytical curve from TGA results enables the accurate determination of cellulose conversion. - Abstract: The ability to determine the quantity of solid reactant that has been transformed after a catalytic reaction is fundamental in accurately defining the conversion of the catalyst. This quantity is also central when investigating the recyclability of a solid catalyst as well as process control in an industrial catalytic application. However, when using carbon-supported catalysts for the conversion of cellulose this value is difficult to obtain using only a gravimetric method. The difficulty lies in weighing errors caused by loss of the solid mixture (catalyst and non-converted cellulose) after the reaction and/or moisture adsorption by the substrate. These errors are then propagated into the conversion calculation giving erroneous results. Thus, a quantitative method using thermogravimetric analysis (TGA) has been developed to determine the quantity of cellulose after a catalytic reaction by using a tungsten carbide catalyst supported on activated carbon. Stepped separation of TGA curves was used for quantitative analysis where three thermal events were identified: moisture loss, cellulose decomposition and CO/CO 2 formation. An analytical curve was derived and applied to quantify the residual cellulose after catalytic reactions which were performed at various temperatures and reaction times. The catalytic conversion was calculated and compared to the standard gravimetric method. Results showed that catalytic cellulose conversion can be determined using TGA and exhibits lower uncertainty (±2%) when compared to gravimetric determination (±5%). Therefore, it is a simple and relatively inexpensive method to determine catalytic
NMR Isotope Tracking Reveals Cascade Steps in Carbohydrate Conversion by Sn-Beta

DEFF Research Database (Denmark)

Elliot, Samuel Gilbert; Taarning, Esben; Madsen, Robert

2017-01-01

Quantitative isotope tracking studies were used to investigate the reaction pathways occurring for Sn-Beta catalyzed carbohydrate conversion to various alpha-hydroxy esters. Experimental insight into the conversion of pentoses was sought (i) by identifying pathways based on isotope patterns in th...
A comprehensive model to determine the effects of temperature and species fluctuations on reaction rates in turbulent reaction flows

Science.gov (United States)

Magnotti, F.; Diskin, G.; Matulaitis, J.; Chinitz, W.

1984-01-01

The use of silane (SiH4) as an effective ignitor and flame stabilizing pilot fuel is well documented. A reliable chemical kinetic mechanism for prediction of its behavior at the conditions encountered in the combustor of a SCRAMJET engine was calculated. The effects of hydrogen addition on hydrocarbon ignition and flame stabilization as a means for reduction of lengthy ignition delays and reaction times were studied. The ranges of applicability of chemical kinetic models of hydrogen-air combustors were also investigated. The CHARNAL computer code was applied to the turbulent reaction rate modeling.
Thermocatalytic CO2-Free Production of Hydrogen from Hydrocarbon Fuels

Energy Technology Data Exchange (ETDEWEB)

University of Central Florida

2004-01-30

The main objective of this project is the development of an economically viable thermocatalytic process for production of hydrogen and carbon from natural gas or other hydrocarbon fuels with minimal environmental impact. The three major technical goals of this project are: (1) to accomplish efficient production of hydrogen and carbon via sustainable catalytic decomposition of methane or other hydrocarbons using inexpensive and durable carbon catalysts, (2) to obviate the concurrent production of CO/CO{sub 2} byproducts and drastically reduce CO{sub 2} emissions from the process, and (3) to produce valuable carbon products in order to reduce the cost of hydrogen production The important feature of the process is that the reaction is catalyzed by carbon particulates produced in the process, so no external catalyst is required (except for the start-up operation). This results in the following advantages: (1) no CO/CO{sub 2} byproducts are generated during hydrocarbon decomposition stage, (2) no expensive catalysts are used in the process, (3) several valuable forms of carbon can be produced in the process depending on the process conditions (e.g., turbostratic carbon, pyrolytic graphite, spherical carbon particles, carbon filaments etc.), and (4) CO{sub 2} emissions could be drastically reduced (compared to conventional processes).

Dedolomitization Potential of Fluids from Gypsum-to-Anhydrite Conversion: Mass Balance Constraints from the Late Permian Zechstein-2-Carbonates in NW Germany

Directory of Open Access Journals (Sweden)

M. Hallenberger

2018-01-01

Full Text Available The Zechstein-2-Carbonates represent one of the most prolific hydrocarbon systems of Central Europe. Carbonate reservoir quality is primarily controlled by mineralogy, with dolomite representing moderate-to-good porosities and calcite commonly representing low porosities. Current models suggest that this calcite is the result of a basin-wide phase of dedolomitization. The calcium (Ca source for the dedolomites is thought to be derived from the fluids liberated during gypsum-to-anhydrite conversion. We present an easy-to-use and generally applicable template to estimate the dedolomitization potential of these fluids. Depending on reaction stoichiometry, salinity, and temperature, we estimate that between 2.8⁎10−3 m3 and 6.2⁎10−3 m3 of calcite may replace dolomite for each m3 of anhydrite created. Within the constraints dictated by the environment of the late Permian Zechstein basin, we estimate that about 5⁎10−3 m3 of dedolomite is created for each m3 of anhydrite. Mass balance constraints indicate that fluids derived from gypsum-to-anhydrite conversion account for less than 1% of the observed dedolomite in most of the studied industry wells from northern Germany.
Production of Jet Fuel-Range Hydrocarbons from Hydrodeoxygenation of Lignin over Super Lewis Acid Combined with Metal Catalysts.

Science.gov (United States)

Wang, Hongliang; Wang, Huamin; Kuhn, Eric; Tucker, Melvin P; Yang, Bin

2018-01-10

Super Lewis acids containing the triflate anion [e.g., Hf(OTf) 4 , Ln(OTf) 3 , In(OTf) 3 , Al(OTf) 3 ] and noble metal catalysts (e.g., Ru/C, Ru/Al 2 O 3 ) formed efficient catalytic systems to generate saturated hydrocarbons from lignin in high yields. In such catalytic systems, the metal triflates mediated rapid ether bond cleavage through selective bonding to etheric oxygens while the noble metal catalyzed subsequent hydrodeoxygenation (HDO) reactions. Near theoretical yields of hydrocarbons were produced from lignin model compounds by the combined catalysis of Hf(OTf) 4 and ruthenium-based catalysts. When a technical lignin derived from a pilot-scale biorefinery was used, more than 30 wt % of the hydrocarbons produced with this catalytic system were cyclohexane and alkylcyclohexanes in the jet fuel range. Super Lewis acids are postulated to strongly interact with lignin substrates by protonating hydroxyl groups and ether linkages, forming intermediate species that enhance hydrogenation catalysis by supported noble metal catalysts. Meanwhile, the hydrogenation of aromatic rings by the noble metal catalysts can promote deoxygenation reactions catalyzed by super Lewis acids. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.
Catalytic Routes for the Conversion of Biomass Derivatives to Hydrocarbons and/or Platform Chemicals

Energy Technology Data Exchange (ETDEWEB)

Silks, III, Louis A. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2015-10-07

Unprotected carbohydrates were reacted in amine-catalyzed cascade reactions with various methyl ketones to give a direct access to C-glycosides by an operationally simple protocol. As the reaction mechanism,an aldol condensation followed by an intramolecular conjugate addition is assumed.
H3PO4/Al2O3 catalysts: characterization and catalytic evaluation of oleic acid conversion to biofuels and biolubricant

Directory of Open Access Journals (Sweden)

Lucia Regina Raddi de Araujo

2006-06-01

Full Text Available Al2O3 and H3PO4/Al2O3 catalysts were investigated in the conversion of oleic acid to biofuels and biolubricant at 1 atm and at 623 K. The catalytic tests were performed in a fixed bed and continuous flow reactor, using an oleic acid-catalyst ratio of 4 and N2 as the carrier gas. The reaction products were analyzed by gas chromatography and acidity measurements. N2 adsorption-desorption, X ray diffraction, 31P nuclear magnetic resonance and FT-IR spectroscopy were also employed to evaluate the textural, structural and acidic properties of the catalysts. The results showed that phosphoric acid impregnation improved the alumina decarboxylation activities, generating hydrocarbons in the range of gasoline, diesel oil and lubricant oil. The best catalytic performance was achieved with the highest surface area alumina impregnated with H3PO4, which was the solid that allied high total acidity with a large quantity of mesopores.
Valorization of biogas into liquid hydrocarbons in plasma-catalyst reactor

Science.gov (United States)

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

2016-09-01

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

Energy Technology Data Exchange (ETDEWEB)

Summons, R.E.

1987-01-01

Linked scanning of a tandem sector mass spectrometer has been used to identify abundant, first field free region (FFR1) unimolecular fragmentations in branched and isoprenoid hydrocarbons. The most intense, structure-specific reactions were selected to establish multiple reaction monitoring (MRM) parameters for GC/MS analysis. This methodology has been used to study the identify of co-eluting and closely eluting hydrocarbon biomarkers from modern and ancient sediments and from extant microorganisms. Some sediments of Cambrian and Proterozoic age have been found to contain suites of monomethylalkanes with all possible isomers present and with little apparent preference for the site of branching.
Endophytic Bacteria Associated with Hieracium piloselloides: Their Potential for Hydrocarbon-Utilizing and Plant Growth-Promotion.

Science.gov (United States)

Pawlik, Małgorzata; Piotrowska-Seget, Zofia

2015-01-01

The aim of this study was to assess the potential of 18 crude-oil-degrading endophytic bacteria for removal of hydrocarbons and promotion of plant growth. Strains were isolated from Hieracium piloselloides (tall hawkweed), which grows in soil heavily polluted with petroleum hydrocarbons. Bacteria from the genus Pseudomonas were abundant among the isolates. The potential for hydrocarbon degradation was evaluated by polymerase chain reaction (PCR) analyses of the genes alkB, alkH, C23O, P450, and pah. It was found that 88.89% of the endophytic bacteria contained gene-encoding polycyclic aromatic hydrocarbon (PAH) initial dioxygenase, 61% possessed the 2,3-catechol dioxygenase gene, and 39% of strains that were tested had the cytochrome P-450 hydroxylase gene. All isolates were capable of producing indole-3-acetic acid (1.8-76.4 μg/ml). Only 17% of them were able to produce siderophores, excrete cellulase, and solubilize phosphate. Hydrogen cyanide synthesis occurred in 33% of endophytic bacteria. The 1-aminocyclopropane-1-carboxylate deaminase activity in isolates that were screened was in the range of 2.6 to 74.1 μmol α-ketobutyrate/mg/h. This feature of the bacteria indicated that isolates may enhance the phytoremediation process. Data suggest that crude-oil-degrading endophytic bacteria possess potential to be promising candidates for enhancement of phytoremediation of hydrocarbon-contaminated soil. Further evaluation of these bacteria is needed in order to assess the role played in the degradation of petroleum hydrocarbons.
Monetization of Nigeria coal by conversion to hydrocarbon fuels through Fischer-Tropsch process

Energy Technology Data Exchange (ETDEWEB)

Oguejiofor, G.C. [Nnamdi Azikiwe University, Awka (Nigeria). Dept. of Chemical Engineering

2008-07-01

Given the instability of crude oil prices and the disruptions in crude oil supply chains, this article offers a complementing investment proposal through diversification of Nigeria's energy source and dependence. Therefore, the following issues were examined and reported: A comparative survey of coal and hydrocarbon reserve bases in Nigeria was undertaken and presented. An excursion into the economic, environmental, and technological justifications for the proposed diversification and roll-back to coal-based resource was also undertaken and presented. The technology available for coal beneficiation for environmental pollution control was reviewed and reported. The Fischer-Tropsch synthesis and its advances into Sasol's slurry phase distillate process were reviewed. Specifically, the adoption of Sasol's advanced synthol process and the slurry phase distillate process were recommended as ways of processing the products of coal gasification. The article concludes by discussing all the above-mentioned issues with regard to value addition as a means of wealth creation and investment.
A Reduced Reaction Scheme for Volatile Nitrogen Conversion in Coal Combustion

DEFF Research Database (Denmark)

Pedersen, Lars Saaby; Glarborg, Peter; Dam-Johansen, Kim

1998-01-01

In pulverised coal flames, the most important volatile nitrogen component forming NOx is HCN. To be able to model the nitrogen chemistry in coal flames it is necessary to have an adequate model for HCN oxidation. The present work was concerned with developing a model for HCN/NH3/NO conversion based...... that the CO/H-2 chemistry was described adequately, the reduced HCN/NH3/NO model compared very well with the detailed model over a wide range of stoichiometries. Decoupling of the HCN chemistry from the CO/H-2 chemistry resulted in over-prediction of the HCN oxidation rate under fuel rich conditions, but had...... negligible effect on the CO/H-2 chemistry. Comparison with simplified HCN models from the literature revealed significant differences, indicating that these models should be used cautiously in modelling volatile nitrogen conversion....
Achievement report for fiscal 2000 on international research cooperation project. Research on technologies to decompose heavy hydrocarbon resources; 2000 nendo jushitsu tanka suiso shigen no bunkai gijutsu ni kansuru kenkyu seika hokokusho

Energy Technology Data Exchange (ETDEWEB)

NONE

2001-03-01

Researches have been made on structuring a hydrocracking process for vacuum distillation residue of Marlim crude oil produced in Brazil (Marlim-VR) being one of the heavy hydrocarbon resources. This paper summarizes the achievements in fiscal 2000. In discussing the hydrocracking conditions, discussions were given on the effects of different iron-based catalysts, reaction pressures, reaction temperatures, effects of solvent addition, and the catalyst made of natural limonite produced in Brazil. As a result, the bottom yield was reduced successfully to 5.5% VR, and conversely oil yield was enhanced up to 84.8% VR by using the limonite produced in Brazil as a catalyst, and by performing bottom recycles under the conditions of 450 degrees C and 10 MPa. In discussing the up-grading of hydrocracking produced oil, a result of 99% by weight or higher was obtained in both of denitration and desulfurization rates. In the fuel evaluation test, a product exceeding 45 being the JIS standard for light oil was derived, which was found a clean product having lower sulfur concentration than the existing heavy oil. (NEDO)
Toluene pyrolysis studies and high temperature reactions of propargyl chloride

Energy Technology Data Exchange (ETDEWEB)

Kern, R.D.; Chen, H.; Qin, Z. [Univ. of New Orleans, LA (United States)

1993-12-01

The main focus of this program is to investigate the thermal decompositions of fuels that play an important role in the pre-particle soot formation process. It has been demonstrated that the condition of maximum soot yield is established when the reaction conditions of temperature and pressure are sufficient to establish a radical pool to support the production of polyaromatic hydrocarbon species and the subsequent formation of soot particles. However, elevated temperatures result in lower soot yields which are attributed to thermolyses of aromatic ring structures and result in the bell-shaped dependence of soot yield on temperature. The authors have selected several acyclic hydrocarbons to evaluate the chemical thermodynamic and kinetic effects attendant to benzene formation. To assess the thermal stability of the aromatic ring, the authors have studied the pyrolyses of benzene, toluene, ethylbenzene, chlorobenzene and pyridine. Time-of-flight mass spectrometry (TOF) is employed to analyze the reaction zone behind reflected shock waves. Reaction time histories of the reactants, products, and intermediates are constructed and mechanisms are formulated to model the experimental data. The TOF work is often performed with use of laser schlieren densitometry (LS) to measure density gradients resulting from the heats of various reactions involved in a particular pyrolytic system. The two techniques, TOF and LS, provide independent and complementary information about ring formation and ring rupture reactions.
Hydrodeoxygenation of methyl esters on sulphided NiMo/{gamma}-Al{sub 2}O{sub 3} and CoMo/{gamma}-Al{sub 2}O{sub 3} catalysts

Energy Technology Data Exchange (ETDEWEB)

Senol, O.I; Viljava, T.R.; Krause, A.O.I. [Laboratory of Industrial Chemistry, Helsinki University of Technology, P.O. Box 6100, FIN-02015 Hut (Finland)

2005-02-28

Wood-derived bio-oil contains high amounts of compounds with different oxygen-containing functional groups that must be removed to improve the fuel characteristics. Elimination of oxygen from carboxylic groups was studied with model compounds, methyl heptanoate and methyl hexanoate, on sulphided NiMo/{gamma}-Al{sub 2}O{sub 3} and CoMo/{gamma}-Al{sub 2}O{sub 3} catalysts in a flow reactor. Catalyst performances and reaction schemes were addressed. Aliphatic methyl esters produced hydrocarbons via three main paths: The first path gave alcohols followed by dehydration to hydrocarbons. Deesterification yielded an alcohol and a carboxylic acid in the second path. Carboxylic acid was further converted to hydrocarbons either directly or with an alcohol intermediate. Decarboxylation of the esters led to hydrocarbons in the third path. No oxygen-containing compounds were detected at complete conversions. However, the product distributions changed with time, even at complete conversions, indicating that both catalysts deactivated under the studied conditions.
Conversion of ammonium uranyl carbonate to UO2 in a fluidized bed

International Nuclear Information System (INIS)

Zhao Jun; Qiu Lufu; Zhong Xing; Xu Heqing

1989-11-01

The conversion of AUC (Ammonium Uranyl Carbonate) to UO 2 was studied in a fluidized bed of 60 mm inner diameter based on the thermodynamics and kinetics data of decomposition-reduction of AUC. The influence of the reaction temperature, composition of fluidization gas and fluidization velocity on conversion were investigated by using N 2 , Ar and circulation gas (mixing gas of H 2 and CO obtained from the exhaust gas of the decomposition of AUC by catalyst crack-conversion) as the fluidization gas. The throughput is up to the high levels (3.32 kg(wet)/h·L) by using circulation gas or mixing of circulation gas and Ar (< 21%) as the fluidization gas when the reaction temperature exceeds 570 deg C
Exhaustive Conversion of Inorganic Nitrogen to Nitrogen Gas Based on a Photoelectro-Chlorine Cycle Reaction and a Highly Selective Nitrogen Gas Generation Cathode.

Science.gov (United States)

Zhang, Yan; Li, Jinhua; Bai, Jing; Shen, Zhaoxi; Li, Linsen; Xia, Ligang; Chen, Shuai; Zhou, Baoxue

2018-02-06

A novel method for the exhaustive conversion of inorganic nitrogen to nitrogen gas is proposed in this paper. The key properties of the system design included an exhaustive photoelectrochemical cycle reaction in the presence of Cl - , in which Cl· generated from oxidation of Cl - by photoholes selectively converted NH 4 + to nitrogen gas and some NO 3 - or NO 2 - . The NO 3 - or NO 2 - was finally reduced to nitrogen gas on a highly selective Pd-Cu-modified Ni foam (Pd-Cu/NF) cathode to achieve exhaustive conversion of inorganic nitrogen to nitrogen gas. The results indicated total nitrogen removal efficiencies of 30 mg L -1 inorganic nitrogen (NO 3 - , NH 4 + , NO 3 - /NH 4 + = 1:1 and NO 2 - /NO 3 - /NH 4 + = 1:1:1) in 90 min were 98.2%, 97.4%, 93.1%, and 98.4%, respectively, and the remaining nitrogen was completely removed by prolonging the reaction time. The rapid reduction of nitrate was ascribed to the capacitor characteristics of Pd-Cu/NF that promoted nitrate adsorption in the presence of an electric double layer, eliminating repulsion between the cathode and the anion. Nitrate was effectively removed with a rate constant of 0.050 min -1 , which was 33 times larger than that of Pt cathode. This system shows great potential for inorganic nitrogen treatment due to the high rate, low cost, and clean energy source.
A Field Scale Investigation of Enhanced Petroleum Hydrocarbon Biodegradation in the Vadose Zone Combining Soil Venting as an Oxygen Source with Moisture and Nutrient Addition

Science.gov (United States)

1990-01-01

herbicides, insecticides, and fungicides is dependent upon both biotic and abiotic reactions, and the rate of these reactions determines the required...The most commonly isolated I hydrocarbon degrading fungi in decreasing order include: Trichoderma , i Penicillium, Aspergillus, and Mortierella (Dragun
Dynamics of O(3P) Reactions with Gaseous Liquid and Solid Hydrocarbons

National Research Council Canada - National Science Library

Hase, William L

2006-01-01

...) were applied to model reactions, including 0 + ethane and related reactions. In the second phase, a semiempirical quantum chemistry method, PM3-SRP, was developed by modifying and reparametrizing the standard PM3 method to fit the ab initio data...
DFT studies of hydrocarbon combustion on metal surfaces.

Science.gov (United States)

Arya, Mina; Mirzaei, Ali Akbar; Davarpanah, Abdol Mahmood; Barakati, Seyed Masoud; Atashi, Hossein; Mohsenzadeh, Abas; Bolton, Kim

2018-02-02

Catalytic combustion of hydrocarbons is an important technology to produce energy. Compared to conventional flame combustion, the catalyst enables this process to operate at lower temperatures; hence, reducing the energy required for efficient combustion. The reaction and activation energies of direct combustion of hydrocarbons (CH → C + H) on a series of metal surfaces were investigated using density functional theory (DFT). The data obtained for the Ag, Au, Al, Cu, Rh, Pt, and Pd surfaces were used to investigate the validity of the Brønsted-Evans-Polanyi (BEP) and transition state scaling (TSS) relations for this reaction on these surfaces. These relations were found to be valid (R 2 = 0.94 for the BEP correlation and R 2 = 1.0 for the TSS correlation) and were therefore used to estimate the energetics of the combustion reaction on Ni, Co, and Fe surfaces. It was found that the estimated transition state and activation energies (E TS = -69.70 eV and E a = 1.20 eV for Ni, E TS = -87.93 eV and E a = 1.08 eV for Co and E TS = -92.45 eV and E a = 0.83 eV for Fe) are in agreement with those obtained by DFT calculations (E TS = -69.98 eV and E a = 1.23 eV for Ni, E TS = -87.88 eV and E a = 1.08 eV for Co and E TS = -92.57 eV and E a = 0.79 eV for Fe). Therefore, these relations can be used to predict energetics of this reaction on these surfaces without doing the time consuming transition state calculations. Also, the calculations show that the activation barrier for CH dissociation decreases in the order Ag ˃ Au ˃ Al ˃ Cu ˃ Pt ˃ Pd ˃ Ni > Co > Rh > Fe.
Solar energy conversion

CERN Document Server

Likhtenshtein, Gertz I

2012-01-01

Finally filling a gap in the literature for a text that also adopts the chemist?s view of this hot topic, Prof Likhtenshtein, an experienced author and internationally renowned scientist, considers different physical and engineering aspects in solar energy conversion. From theory to real-life systems, he shows exactly which chemical reactions take place when converting light energy, providing an overview of the chemical perspective from fundamentals to molecular harvesting systems and solar cells. This essential guide will thus help researchers in academia and industry better understa
Pyrolysis and liquefaction of acetone and mixed acetone/ tetralin swelled Mukah Balingian Malaysian sub-bituminous coal-The effect on coal conversion and oil yield

International Nuclear Information System (INIS)

Mohd Pauzi Abdullah; Mohd Azlan Mohd Ishak; Khudzir Ismail

2008-01-01

The effect of swelling on Mukah Balingian (MB) Malaysian sub-bituminous coal macrostructure was observed by pyrolysing the swelled coal via thermogravimetry under nitrogen at ambient pressure. The DTG curves of the pyrolyzed swelled coal samples show the presence of evolution peaks at temperature ranging from 235 - 295 degree Celsius that are due to releasing of light molecular weight hydrocarbons. These peaks, however, were not present in the untreated coal, indicating some changes in the coal macrostructure has occurred in the swelled coal samples. The global pyrolysis kinetics for coal that follows the first-order decomposition reaction was used to evaluate the activation energy of the pyrolyzed untreated and swelled coal samples. The results thus far have shown that the activation energy for the acetone and mixed acetone/ tetralin-swelled coal samples exhibit lower values than untreated coal, indicating less energy is required during the pyrolysis process due to the weakening of the coal-coal macromolecular interaction network. Moreover, liquefaction on the swelled coal samples that was carried out at temperatures ranging from 360 to 450 degree Celsius at 4 MPa of nitrogen pressure showed the enhancement of the coal conversion and oil yield at temperature of 420 degree Celsius, with retrogressive reaction started to dominate at higher temperature as indicated by decreased and increased in oil yield and high molecular weight pre-asphaltene, respectively. These observations suggest that the solvent swelling pre-treatment using acetone and mixed acetone/ tetralin can improve the coal conversion and oil yields at less severe liquefaction condition. (author)
Semi-Batch Reactive Distillation of Consecutive Reaction : The Saponification Reaction of Diethyl Adipate with Sodium Hydroxide Solution

Directory of Open Access Journals (Sweden)

Raghad Fareed Kasim

2016-03-01

Full Text Available This research presents a new study in reactive distillation by using consecutive reaction: the saponification reaction of diethyl adipate (DA with sodium hydroxide solution . The effect of three parameters were studied through a design of experiments applying 23 factorial design . These parameters were : the mole ratio of DA to NaOH solution (0.1 and 1 , NaOH solution concentration (3 N and 8 N , and batch time (1.5 hr. and 3.5 hr. . The conversion of DA to sodium monoethyladipate(SMA(intermediate product was the effect of these parameters which was detected . Also , the percentage purity of the intermediate product was recorded . The results showed that increasing mole ratio of DA to NaOHsolution increases the conversion and percentage purity to a maximum value within the range of study . The effect of NaOH solution concentration decreases the conversion and percentage purity to specified value within the range of study . The effect of batch time on conversion and percentage purity , when NaOH solution concentration (3 N is as follows : the increasing in batch time decreases the conversion and percentage purity to specified value within the range of study . When NaOH solution concentration (8 N increasing batch time decreases the conversion , while percentage purity increases with increasing batch time to a maximum value within the range of study . The maximum attainable conversion within the studied range of parameters was eighteen fold of the base case , while the maximum percentage purity was (99.40 % . Empirical equation was obtained using statistical analysis of experimental results . The empirical results of relative conversion was drawn . The empirical graphs showed linear variation .

Versatility of hydrocarbon production in cyanobacteria.

Science.gov (United States)

Xie, Min; Wang, Weihua; Zhang, Weiwen; Chen, Lei; Lu, Xuefeng

2017-02-01

Cyanobacteria are photosynthetic microorganisms using solar energy, H 2 O, and CO 2 as the primary inputs. Compared to plants and eukaryotic microalgae, cyanobacteria are easier to be genetically engineered and possess higher growth rate. Extensive genomic information and well-established genetic platform make cyanobacteria good candidates to build efficient biosynthetic pathways for biofuels and chemicals by genetic engineering. Hydrocarbons are a family of compounds consisting entirely of hydrogen and carbon. Structural diversity of the hydrocarbon family is enabled by variation in chain length, degree of saturation, and rearrangements of the carbon skeleton. The diversified hydrocarbons can be used as valuable chemicals in the field of food, fuels, pharmaceuticals, nutrition, and cosmetics. Hydrocarbon biosynthesis is ubiquitous in bacteria, yeasts, fungi, plants, and insects. A wide variety of pathways for the hydrocarbon biosynthesis have been identified in recent years. Cyanobacteria may be superior chassis for hydrocabon production in a photosynthetic manner. A diversity of hydrocarbons including ethylene, alkanes, alkenes, and terpenes can be produced by cyanobacteria. Metabolic engineering and synthetic biology strategies can be employed to improve hydrocarbon production in cyanobacteria. This review mainly summarizes versatility and perspectives of hydrocarbon production in cyanobacteria.
Subduction zone earthquake probably triggered submarine hydrocarbon seepage offshore Pakistan

Science.gov (United States)

Fischer, David; José M., Mogollón; Michael, Strasser; Thomas, Pape; Gerhard, Bohrmann; Noemi, Fekete; Volkhard, Spiess; Sabine, Kasten

2014-05-01

Seepage of methane-dominated hydrocarbons is heterogeneous in space and time, and trigger mechanisms of episodic seep events are not well constrained. It is generally found that free hydrocarbon gas entering the local gas hydrate stability field in marine sediments is sequestered in gas hydrates. In this manner, gas hydrates can act as a buffer for carbon transport from the sediment into the ocean. However, the efficiency of gas hydrate-bearing sediments for retaining hydrocarbons may be corrupted: Hypothesized mechanisms include critical gas/fluid pressures beneath gas hydrate-bearing sediments, implying that these are susceptible to mechanical failure and subsequent gas release. Although gas hydrates often occur in seismically active regions, e.g., subduction zones, the role of earthquakes as potential triggers of hydrocarbon transport through gas hydrate-bearing sediments has hardly been explored. Based on a recent publication (Fischer et al., 2013), we present geochemical and transport/reaction-modelling data suggesting a substantial increase in upward gas flux and hydrocarbon emission into the water column following a major earthquake that occurred near the study sites in 1945. Calculating the formation time of authigenic barite enrichments identified in two sediment cores obtained from an anticlinal structure called "Nascent Ridge", we find they formed 38-91 years before sampling, which corresponds well to the time elapsed since the earthquake (62 years). Furthermore, applying a numerical model, we show that the local sulfate/methane transition zone shifted upward by several meters due to the increased methane flux and simulated sulfate profiles very closely match measured ones in a comparable time frame of 50-70 years. We thus propose a causal relation between the earthquake and the amplified gas flux and present reflection seismic data supporting our hypothesis that co-seismic ground shaking induced mechanical fracturing of gas hydrate-bearing sediments
Cherenkov radiation conversion and collection considerations for a gamma bang time/reaction history diagnostic for the NIF.

Science.gov (United States)

Herrmann, Hans W; Mack, Joseph M; Young, Carlton S; Malone, Robert M; Stoeffl, Wolfgang; Horsfield, Colin J

2008-10-01

Bang time and reaction history measurements are fundamental components of diagnosing inertial confinement fusion (ICF) implosions and will be essential contributors to diagnosing attempts at ignition on the National Ignition Facility (NIF). Fusion gammas provide a direct measure of fusion interaction rate without being compromised by Doppler spreading. Gamma-based gas Cherenkov detectors that convert fusion gamma rays to optical Cherenkov photons for collection by fast recording systems have been developed and fielded at Omega. These systems have established their usefulness in illuminating ICF physics in several experimental campaigns. Bang time precision better than 25 ps has been demonstrated, well below the 50 ps accuracy requirement defined by the NIF system design requirements. A comprehensive, validated numerical study of candidate systems is providing essential information needed to make a down selection based on optimization of sensitivity, bandwidth, dynamic range, cost, and NIF logistics. This paper presents basic design considerations arising from the two-step conversion process from gamma rays to relativistic electrons to UV/visible Cherenkov radiation.
Cherenkov radiation conversion and collection considerations for a gamma bang time/reaction history diagnostic for the NIF

International Nuclear Information System (INIS)

Herrmann, Hans W.; Mack, Joseph M.; Young, Carlton S.; Malone, Robert M.; Stoeffl, Wolfgang; Horsfield, Colin J.

2008-01-01

Bang time and reaction history measurements are fundamental components of diagnosing inertial confinement fusion (ICF) implosions and will be essential contributors to diagnosing attempts at ignition on the National Ignition Facility (NIF). Fusion gammas provide a direct measure of fusion interaction rate without being compromised by Doppler spreading. Gamma-based gas Cherenkov detectors that convert fusion gamma rays to optical Cherenkov photons for collection by fast recording systems have been developed and fielded at Omega. These systems have established their usefulness in illuminating ICF physics in several experimental campaigns. Bang time precision better than 25 ps has been demonstrated, well below the 50 ps accuracy requirement defined by the NIF system design requirements. A comprehensive, validated numerical study of candidate systems is providing essential information needed to make a down selection based on optimization of sensitivity, bandwidth, dynamic range, cost, and NIF logistics. This paper presents basic design considerations arising from the two-step conversion process from γ rays to relativistic electrons to UV/visible Cherenkov radiation.
Hydrocarbon Plume Dynamics in the Worldś Most Spectacular Hydrocarbon Seeps, Santa Barbara Channel, California

Science.gov (United States)

Mau, S.; Reed, J.; Clark, J.; Valentine, D.

2006-12-01

Large quantities of natural gas are emitted from the seafloor into the coastal ocean near Coal Oil Point, Santa Barbara Channel (SBC), California. Methane, ethane, and propane were quantified in the surface water at 79 stations in a 270 km2 area in order to map the surficial hydrocarbon plume and to quantify air-sea exchange of these gases. A time series was initiated for 14 stations to identify the variability of the mapped plume, and biologically-mediated oxidation rates of methane were measured to quantify the loss of methane in surface water. The hydrocarbon plume was found to comprise ~70 km2 and extended beyond study area. The plume width narrowed from 3 km near the source to 0.7 km further from the source, and then expanded to 6.7 km at the edge of the study area. This pattern matches the cyclonic gyre which is the normal current flow in this part of the Santa Barbara Channel - pushing water to the shore near the seep field and then broadening the plume while the water turns offshore further from the source. Concentrations of gaseous hydrocarbons decrease as the plume migrates. Time series sampling shows similar plume width and hydrocarbon concentrations when normal current conditions prevail. In contrast, smaller plume width and low hydrocarbon concentrations were observed when an additional anticyclonic eddy reversed the normal current flow, and a much broader plume with higher hydrocarbon concentrations was observed during a time of diminished speed within the current gyre. These results demonstrate that surface currents control hydrocarbon plume dynamics in the SBC, though hydrocarbon flux to the atmosphere is likely less dependent on currents. Estimates of air- sea hydrocarbon flux and biological oxidation rates will also be presented.
Light energy conversion by photocatalytic reaction

Energy Technology Data Exchange (ETDEWEB)

Fujishima, Akira; Yamagata, Sadamu [Univ. of Tokyo (Japan)

1989-01-01

The photocatalytic reaction, to be made to a suspended semiconductor powder system, was explained in summary. By using semiconductor as an electrode for the electrolyzation, etc. and projecting light on it to generate photoelectromotive force, a photocell can be composed. eg., by composing titanium oxide electrode, n-type semiconductor and platinum electrode, and irradiating light on the former electrode to generate electric current, oxygen and hydrogen are produced from the titanium oxide electrode and platinum electrode, respectively, which means the possibility of obtainment of clean energy from water as raw material. Such a wet type photocell, easy to produce, is active also in research. With white titanium oxide powder being suspended in water solution, hydrogen is produced by projecting light into it. Such a semiconductor is called photocatalyst, in which the research has been widely developed, mainly by taking notice of the hydrogen production on reduction side, since 1972. The photocatalysis using colloid and, differently, that doing heteropolyacid are also taken notice of. 24 refs., 6 figs.
Monitoring biodegradation of hydrocarbons by stable isotope fractionation

Science.gov (United States)

Dorer, Conrad; Fischer, Anko; Herrmann, Steffi; Richnow, Hans-Hermann; Vogt, Carsten

2010-05-01

In the last decade, several studies have demonstrated that stable isotope tools are highly applicable for monitoring anaerobic biodegradation processes. An important methodological approach is to characterize distinct degradation pathways with respect to the specific mechanism of C-H-bond cleavage and to quantify the extent of biodegradation by compound specific isotope analysis (CSIA). Here, enrichment factors (ɛbulk) needed for a CSIA field site approach must be determined in laboratory reference experiments. Recent research results from different laboratories have shown that single ɛbulk values for similar degradation pathways can be highly variable; thus, the use of two-dimensional compound specific isotope analysis (2D-CSIA) has been encouraged for characterizing biodegradation pathways more precisely. 2D-CSIA for hydrocarbons can be expressed by the slope of the linear regression for hydrogen versus carbon discrimination known as lambda ≈ ɛHbulk/ɛCbulk. We determined the carbon and hydrogen isotope fractionation for the biodegradation of benzene, toluene and xylenes by various reference cultures. Specific enzymatic reactions initiating different biodegradation pathways could be distinguished by 2D-CSIA. For the aerobic di- and monohydroxylation of the benzene ring, lambda values always lower than 9 were observed. Enrichment cultures degrading benzene anaerobically produced significant different values: lambda values between 8-19 were oberved for nitrate-reducing consortia, whereas sulfate-reducing and methanogenic consortia showed always lambda values greater than 20 [1,2]. The observed variations suggest that (i) aerobic benzene biodegradation can be distinguished from anaerobic biodegradation, and (ii) that more than a single mechanism seems to exist for the activation of benzene under anoxic conditions. lambda values for anaerobic toluene degradation initiated by the enzyme benzylsuccinate synthase (BSS) ranged from 4 to 41, tested with strains using
Catalytic and Noncatalytic Conversion of Methane to Olefins and Synthesis Gas in an AC Parallel Plate Discharge Reactor

Directory of Open Access Journals (Sweden)

Mohammad Ali Khodagholi

2013-01-01

Full Text Available Direct conversion of methane to ethylene, acetylene, and synthesis gas at ambient pressure and temperature in a parallel plate discharge reactor was investigated. The experiments were carried out using a quartz reactor of outer diameter of 9 millimeter and a driving force of ac current of 50 Hz. The input power to the reactor to establish a stable gas discharge varied from 9.6 to maximum 15.3 watts (w. The effects of ZSM5, Fe–ZSM5, and Ni–ZSM5 catalysts combined with corona discharge for conversion of methane to more valued products have been addressed. It was found that in presence or absence of a catalyst in gas discharge reactor, the rate of methane and oxygen conversion increased upon higher input power supplied to the reactor. The effect of Fe–ZSM5 catalyst combined with gas discharge plasma yields C2 hydrocarbons up to 21.9%, which is the highest productions of C2 hydrocarbons in this work. The effect of combined Ni–ZSM5 and gas discharge plasma was mainly production of synthesis gas. The advantage of introducing ZSM5 to the plasma zone was increase in synthesis gas and acetylene production. The highest energy efficiency was 0.22 mmol/kJ, which belongs to lower rate of energy injection to the reactor.
Predicting hydrocarbon release from soil

International Nuclear Information System (INIS)

Poppendieck, D.; Loehr, R.C.

2002-01-01

'Full text:' The remediation of hazardous chemicals from soils can be a lengthy and costly process. As a result, recent regulatory initiatives have focused on risk-based corrective action (RBCA) approaches. Such approaches attempt to identify the amount of chemical that can be left at a site with contaminated soil and still be protective of human health and the environment. For hydrocarbons in soils to pose risk to human heath and the environment, the hydrocarbons must be released from the soil and accessible to microorganisms, earthworms, or other higher level organisms. The sorption of hydrocarbons to soil can reduce the availability of the hydrocarbon to receptors. Typically in soils and sediments, there is an initial fast release of a hydrocarbon from the soil to the aqueous phase followed by a slower release of the remaining hydrocarbon to the aqueous phase. The rate and extent of slow release can influence aqueous hydrocarbon concentrations and the fate and transport of hydrocarbons in the subsurface. Once the fast fraction of the chemical has been removed from the soil, the remaining fraction of a chemical may desorb at a rate that natural mechanisms can attenuate the released hydrocarbon. Hence, active remediation may be needed only until the fast fraction has been removed. However, the fast fraction is a soil and chemical specific parameter. This presentation will present a tier I type protocol that has been developed to quickly estimate the fraction of hydrocarbons that are readily released from the soil matrix to the aqueous phase. Previous research in our laboratory and elsewhere has used long-term desorption (four months) studies to determine the readily released fraction. This research shows that a single short-term (less than two weeks) batch extraction procedure provides a good estimate of the fast released fraction derived from long-term experiments. This procedure can be used as a tool to rapidly evaluate the release and bioavailability of
Biogenic non-methane hydrocarbons (NMHC). Nature`s contribution to regional and global atmospheric chemistry

Energy Technology Data Exchange (ETDEWEB)

Klockow, D.; Hoffman, T. [Inst. of Spectrochemistry and Applied Spectroscopy, Dortmund (Germany)

1995-12-31

Terrestrial vegetation provides an important source of volatile hydrocarbons, especially isoprene, monoterpenes and in addition possibly sesquiterpenes as well as oxygenated compounds. Although there exist considerable uncertainties in the estimation of the magnitude of these biogenic NMHC emissions, it is generally accepted that the majority of global NMHC release is from natural and not from anthropogenic sources. Taking into consideration the high reactivity of the mostly unsaturated biogenic emissions, their impact on tropospheric processes can be assumed to be of great importance. Together with anthropogenic NO{sub x} emissions, the highly reactive natural alkenes can act as precursors in photochemical oxidant formation and contribute to regional-scale air pollution. Their oxidation in the atmosphere and the subsequent gas-to-particle conversion of the products lead to the formation of organic aerosols. Because of the formation of phytotoxic compounds, the interaction of the biogenic hydrocarbons with ozone inside or outside the leaves and needles of plants has been suggested to play a role in forest decline. (author)
Biogenic non-methane hydrocarbons (NMHC). Nature`s contribution to regional and global atmospheric chemistry

Energy Technology Data Exchange (ETDEWEB)

Klockow, D; Hoffman, T [Inst. of Spectrochemistry and Applied Spectroscopy, Dortmund (Germany)

1996-12-31

Terrestrial vegetation provides an important source of volatile hydrocarbons, especially isoprene, monoterpenes and in addition possibly sesquiterpenes as well as oxygenated compounds. Although there exist considerable uncertainties in the estimation of the magnitude of these biogenic NMHC emissions, it is generally accepted that the majority of global NMHC release is from natural and not from anthropogenic sources. Taking into consideration the high reactivity of the mostly unsaturated biogenic emissions, their impact on tropospheric processes can be assumed to be of great importance. Together with anthropogenic NO{sub x} emissions, the highly reactive natural alkenes can act as precursors in photochemical oxidant formation and contribute to regional-scale air pollution. Their oxidation in the atmosphere and the subsequent gas-to-particle conversion of the products lead to the formation of organic aerosols. Because of the formation of phytotoxic compounds, the interaction of the biogenic hydrocarbons with ozone inside or outside the leaves and needles of plants has been suggested to play a role in forest decline. (author)
Hydrocarbons

Energy Technology Data Exchange (ETDEWEB)

1927-02-22

Coal tar, mineral oils, bitumens, coal extraction products, hydrogenation products of coal, oil schists can be atomized and heated with steam to decompose pyrogenetically and form gases rich in olefins which may be heated with or without pressure and with or without catalysts to produce liquid hydrocarbons of low boiling point, some of which may be aromatic. The apparatus should be lined with copper, silica, or ferrosilicon to prevent contact of the bases with iron which causes deposition of soot. Catalysts used may be metal oxides, silica, graphite, active charcoal, mica, pumice, porcelain, barium carbonate, copper, silver, gold, chromium, boron, or their compounds. At temperatures from 300 to 400/sup 0/C, olefins are produced. At higher temperatures, naphthenes and benzene hydrocarbons are produced.
Recycling Carbon Dioxide into Sustainable Hydrocarbon Fuels: Electrolysis of Carbon Dioxide and Water

Science.gov (United States)

Graves, Christopher Ronald

Great quantities of hydrocarbon fuels will be needed for the foreseeable future, even if electricity based energy carriers begin to partially replace liquid hydrocarbons in the transportation sector. Fossil fuels and biomass are the most common feedstocks for production of hydrocarbon fuels. However, using renewable or nuclear energy, carbon dioxide and water can be recycled into sustainable hydrocarbon fuels in non-biological processes which remove oxygen from CO2 and H2O (the reverse of fuel combustion). Capture of CO2 from the atmosphere would enable a closed-loop carbon-neutral fuel cycle. The purpose of this work was to develop critical components of a system that recycles CO2 into liquid hydrocarbon fuels. The concept is examined at several scales, beginning with a broad scope analysis of large-scale sustainable energy systems and ultimately studying electrolysis of CO 2 and H2O in high temperature solid oxide cells as the heart of the energy conversion, in the form of three experimental studies. The contributions of these studies include discoveries about electrochemistry and materials that could significantly improve the overall energy use and economics of the CO2-to-fuels system. The broad scale study begins by assessing the sustainability and practicality of the various energy carriers that could replace petroleum-derived hydrocarbon fuels, including other hydrocarbons, hydrogen, and storage of electricity on-board vehicles in batteries, ultracapacitors, and flywheels. Any energy carrier can store the energy of any energy source. This sets the context for CO2 recycling -- sustainable energy sources like solar and wind power can be used to provide the most energy-dense, convenient fuels which can be readily used in the existing infrastructure. The many ways to recycle CO2 into hydrocarbons, based on thermolysis, thermochemical loops, electrolysis, and photoelectrolysis of CO2 and/or H 2O, are critically reviewed. A process based on high temperature co
Prospects for development of hydrocarbon raw materials resources reproduction

Science.gov (United States)

Vertakova, Y. V.; Babich, T. N.; Polozhentseva, Y. S.; Zvyagintsev, G. L.

2017-10-01

The article presents data on the influence of factors in the field of innovative technology of thermocatalytic depolymerization of solid household wastes (SHW) on the efficiency and prospects for the development of technogenic hydrocarbon raw materials resource reproduction. Process thermodynamics, reactions kinetics, the mechanism of thermolysis of secondary polymers in organic solvents have been studied by means of laboratory experiments. It is shown that different morphological groups of wastes dissolve practically at the same rate at temperatures of 250-310°C. A homogeneous product is formed in the liquid phase; the spread of values for the elements lies in the interval of 1.5-4.5 %; technological requirements of the stages of formation of boiler fuels are satisfied. Using the principles of patent analysis, new techniques of processing household waste components are proposed. The basics of energy-efficient and energy-saving processes of technogenic hydrocarbon raw materials resource reproduction have been laid. The possibility of increasing the production payback and intensification is shown. Ecological and demographic safety for population and technical and economic benefits from SHW processing are achieved.
Early events following radiolytic and photogeneration of radical cations in hydrocarbons

International Nuclear Information System (INIS)

Werst, D.W.; Trifunac, A.D.

1992-01-01

Real-time studies in hydrocarbons have revealed a richness of chemistry involving the initial ionic species produced in radiolysis and photoionization. A modified radical cation mechanism patterned after the core mechanism for alkane radiolysis-formation of radical cations and their disappearance via ion-molecule reactions - is capable of explaining a wide range of observations in high-energy photochemistry, and thus unifies two high-energy regimes. Fundamental studies of radical cations suggest strategies for mitigating radiation effects in materials
SOLID FUEL OF HYDROCARBON, WOOD AND AGRICULTURAL WASTE FOR LOCAL HEAT SUPPLY SYSTEMS

Directory of Open Access Journals (Sweden)

B. M. Khroustalev

2017-01-01

Full Text Available In Belarus oil refining and oil producing industries are paid close attention. On the background of the active maintaining the level of oil processing and volume of oil extraction in our country and in the countries of the Eurasian Economic Union there is a steady formation of hydrocarbon-containing waste; therefore recycling of the latter is an urgent task to improve the competitiveness of production. The most cost-effective way of using hydrocarbon waste is the conversion of it into power resources. In this case it is possible to obtain significant power-saving and economic effect of the combined use of a hydrocarbon, wood, agricultural and other combustible waste, meanwhile improving the ecological situation at the sites of waste storage and creating a solid fuel with the necessary energy and specified physical-and-chemical properties. A comprehensive solution of a recycling problem makes it possible to use as energy resources a lot of waste that has not found application in other technologies, to produce alternative multi-component fuel which structure meets environmental and energy requirement for local heating systems. In addition, the implementation of such technology will make it possible to reduce power consumption of enterprises of various kinds that consume fuel and will also increase the share of local fuels in the energy balance of a particular region.
A new HYSYS model for underground gasification of hydrocarbons under hydrothermal conditions

KAUST Repository

Alshammari, Y.M.

2014-08-01

A new subsurface process model was developed using the ASPEN HYSYS simulation environment to analyse the process energy and gasification efficiency at steady-state equilibrium conditions. Injection and production wells were simulated using the HYSYS pipe flow utilities which makes use of the Beggs and Brill flow correlation applicable for vertical pipes. The downhole reservoir hydrothermal reactions were assumed to be in equilibrium, and hence, the Gibbs reactor was used. It was found that high W/C ratios and low O/C ratios are required to maximise gasification efficiency at a constant hydrocarbon feed flowrate, while the opposite is true for the energy efficiency. This occurs due to the dependence of process energy efficiency on the gas pressure and temperature at surface, while the gasification efficiency depends on the gas composition which is determined by the reservoir reaction conditions which affects production distribution. Another effect of paramount importance is the increase in reservoir production rate which was found to directly enhance both energy and gasification efficiency showing conditions where the both efficiencies are theoretically maximised. Results open new routes for techno-economic assessment of commercial implementation of underground gasification of hydrocarbons. © 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.
Wet Oxidation of Fine Soil Contaminated with Petroleum Hydrocarbons: A Way towards a Remediation Cycle

Directory of Open Access Journals (Sweden)

Maria Cristina Collivignarelli

2018-06-01

Full Text Available The aim of this experimental study was to assess the feasibility of using a wet oxidation (WO process for treating fine soil with a high level of total petroleum hydrocarbons (TPHs. Two samples of soil were spiked with two different contaminants (motor oil, and motor oil + diesel. The samples were subjected to a WO bench plant test, where the effect of the main process parameters (i.e., temperature and reaction time on the removal of TPHs was investigated. Results show that the WO process is effective for the decontamination of hydrocarbons, and a strong reduction (>85% can be obtained with the typical working conditions of a full-scale plant (temperature = 250 °C, reaction time = 30 min. The solid residue resulting from the WO process was characterized in order to evaluate the recovery options. In terms of chemical characterization, the contents of the pollutants comply with the Italian regulations for commercial and industrial site use. Moreover, the results of the leaching test suggested that these residues could be reused for ceramic and brick manufacturing processes.
Resident Reactions to Person-Centered Communication by Long-Term Care Staff.

Science.gov (United States)

Savundranayagam, Marie Y; Sibalija, Jovana; Scotchmer, Emma

2016-09-01

Long-term care staff caregivers who are person centered incorporate the life history, preferences, and feelings of residents with dementia during care interactions. Communication is essential for person-centered care. However, little is known about residents' verbal reactions when staff use person-centered communication. Accordingly, this study investigated the impact of person-centered communication and missed opportunities for such communication by staff on resident reactions. Conversations (N = 46) between staff-resident dyads were audio-recorded during routine care tasks over 12 weeks. Staff utterances were coded for person-centered communication and missed opportunities. Resident utterances were coded for positive reactions, such as cooperation, and negative reactions, such as distress. Linear regression analyses revealed that the more staff used person-centered communication, the more likely that residents reacted positively. Additionally, the more missed opportunities in a conversation, the more likely that the residents reacted negatively. Conversation illustrations elaborate on the quantitative findings and implications for staff training are discussed. © The Author(s) 2016.
Innocuous oil as an additive for reductive reactions involving zero valence iron

International Nuclear Information System (INIS)

Cary, J.W.; Cantrell, K.J.

1994-11-01

Reductive reactions involving zero valence iron appear to hold promise for in situ remediation of sites containing chlorinated hydrocarbon solvents and certain reducible metals and radionuclides. Treatment involves the injection of metallic iron and the creation of low levels of dissolved oxygen in the aqueous phase through oxidation of the metallic iron. The use of a biodegradable immiscible and innocuous organic liquid such as vegetable oil as an additive offers several intriguing possibilities. The oil phase creates a large oil-water interface that is immobile with respect to flow in the aqueous phase. This phase will act as a trap for chlorinated hydrocarbons and could potentially increase the reaction efficiency of reductive dehalogenation of chlorinated hydrocarbons by the metallic iron. When iron particles are suspended in the oil before injection they are preferentially held in the oil phase and tend to accumulate at the oil-water interface. Thus oil injection can serve as a mechanism for creating a stable porous curtain of metallic iron in the vadose to maintain a low oxygen environment which will minimize the consumption of the iron by molecular oxygen

Capability of the Direct Dimethyl Ether Synthesis Process for the Conversion of Carbon Dioxide

Directory of Open Access Journals (Sweden)

Ainara Ateka

2018-04-01

Full Text Available The direct synthesis of dimethyl ether (DME is an ideal process to achieve the environmental objective of CO2 conversion together with the economic objective of DME production. The effect of the reaction conditions (temperature, pressure, space time and feed composition (ternary mixtures of H2 + CO + CO2 with different CO2/CO and H2/COx molar ratios on the reaction indices (COx conversion, product yield and selectivity, CO2 conversion has been studied by means of experiments carried out in a fixed-bed reactor, with a CuO-ZnO-MnO/SAPO-18 catalyst, in order to establish suitable ranges of operating conditions for enhancing the individual objectives of CO2 conversion and DME yield. The optimums of these two objectives are achieved in opposite conditions, and for striking a good balance between both objectives, the following conditions are suitable: 275–300 °C; 20–30 bar; 2.5–5 gcat h (molC−1 and a H2/COx molar ratio in the feed of 3. CO2/CO molar ratio in the feed is of great importance. Ratios below 1/3 are suitable for enhancing DME production, whereas CO2/CO ratios above 1 improve the conversion of CO2. This conversion of CO2 in the overall process of DME synthesis is favored by the reverse water gas shift equation, since CO is more active than CO2 in the methanol synthesis reaction.
Conversion of Cassava Starch to Produce Glucose and Fructose by Enzymatic Process Using Microwave Heating

Directory of Open Access Journals (Sweden)

Sumardiono Siswo

2018-01-01

Full Text Available In this study, variation of glycosidase enzyme concentration and saccharification time on enzymatic hydrolysis using microwave have been investigated. Concentration and kinetic parameters rate of glucose and fructose were analyzed. Cassava starch was liquefied and gelatinized by microwave at 80°C. The gelatinized starch was saccharified at 60°C using (0.2;0.4;0.6;0.8;1% (w/v glycosidase enzyme for 24, 48 and 72 hours. The glucose which has been saccharified with 1% glycosidase enzyme for 72 hours gave highest conversion 66.23 %. The optimization process by multilevel reaction gave the highest conversion at enzyme concentrations 0.88 %and saccharification time 29 hours that 68.82%. The highest conversion of glucose was isomerized to fructose. The fructose which has been isomerized for 180 minutes gave highest conversion 20.05 %. The kinetics enzymatic reaction was approached and determined by Michaelis - Menten equation, Km and Vmax of reaction for glucose 22.94 g/L; 2.70 g/L hours and for fructose 3.39 g/L; 0.38 g/L. min respectively.
LOW TEMPERATURE FORMATION OF NITROGEN-SUBSTITUTED POLYCYCLIC AROMATIC HYDROCARBONS (PANHs)—BARRIERLESS ROUTES TO DIHYDRO(iso)QUINOLINES

Energy Technology Data Exchange (ETDEWEB)

Parker, Dorian S. N.; Yang, Tao; Dangi, Beni B.; Kaiser, Ralf I. [Department of Chemistry, University of Hawaii at Manoa, Honolulu, HI 96822 (United States); Bera, Partha P.; Lee, Timothy J., E-mail: ralfk@hawaii.edu, E-mail: Timothy.J.Lee@nasa.gov [Space Science and Astrobiology Division, NASA Ames Research Center, Moffett Field, Mountain View, CA 94035 (United States)

2015-12-20

Meteorites contain bio-relevant molecules such as vitamins and nucleobases, which consist of aromatic structures with embedded nitrogen atoms. Questions remain over the chemical mechanisms responsible for the formation of nitrogen-substituted polycyclic aromatic hydrocarbons (PANHs) in extraterrestrial environments. By exploiting single collision conditions, we show that a radical mediated bimolecular collision between pyridyl radicals and 1,3-butadiene in the gas phase forms nitrogen-substituted polycyclic aromatic hydrocarbons (PANHs) 1,4-dihydroquinoline and to a minor amount 1,4-dihydroisoquinoline. The reaction proceeds through the formation of a van der Waals complex, which circumnavigates the entrance barrier implying it can operate at very low kinetic energy and therefore at low temperatures of 10 K as present in cold molecular clouds such as TMC-1. The discovery of facile de facto barrierless exoergic reaction mechanisms leading to PANH formation could play an important role in providing a population of aromatic structures upon which further photo-processing of ice condensates could occur to form nucleobases.
Upgrading pine sawdust pyrolysis oil to green biofuels by HDO over zinc-assisted Pd/C catalyst

International Nuclear Information System (INIS)

Huang, Yinbin; Wei, Lin; Zhao, Xianhui; Cheng, Shouyun; Julson, James; Cao, Yuhe; Gu, Zhengrong

2016-01-01

Highlights: • The Pd/Zn synergistic catalysis was employed. • The true pyrolysis oil as substrate was used in HDO. • The products (gas and liquid) were analyzed. • The optimal reaction conditions were obtained. - Abstract: Upgrading pyrolysis oil by hydrodeoxygenation (HDO) is a promising route for the production of advanced biofuels. The proper reaction conditions and catalysts are important for the success of this process. Previously our research group investigated the ratio of Zn and Pd on the synergistic effect for HDO bio-oil upgrading. This present research focuses on determining the optimal reaction conditions for HDO conversion of pyrolysis oil produced from pine sawdust. Temperatures of 150, 200 and 250 °C and hydrogen pressures of 1.38, 2.76 and 4.14 MPa were evaluated. Syngas, liquids and coke were the primary products evaluated. Syngas was characterized using a Gas chromatography (GC). The liquids were characterized using a Gas chromatography–mass spectrometry (GC–MS). Increasing reaction temperature resulted in increased coke yields. Treatment at 250 °C and 1.38 MPa resulted in the highest hydrocarbon content (6.06%). The treatment at 200 °C and 1.38 MPa produced the largest amounts of hydrocarbons in C_6–C_1_2 range (5.07%). The physicochemical characterizations further support the GCMS results. Syngas analysis revealed that higher hydrogen pressure leads to increased hydrogen consumption and results in more oxy-compounds conversion to hydrocarbons. The syngas analysis also supports the liquid analysis result.
Surface chemical reactions probed with scanning force microscopy

NARCIS (Netherlands)

Werts, M.P L; van der Vegte, E.W.; Hadziioannou, G

1997-01-01

In this letter we report the study of surface chemical reactions with scanning force microscopy (SFM) with chemical specificity. Using chemically modified SFM probes, we can determine the local surface reaction conversion during a chemical surface modification. The adhesion forces between a
MoS2 monolayer catalyst doped with isolated Co atoms for the hydrodeoxygenation reaction

Science.gov (United States)

Liu, Guoliang; Robertson, Alex W.; Li, Molly Meng-Jung; Kuo, Winson C. H.; Darby, Matthew T.; Muhieddine, Mohamad H.; Lin, Yung-Chang; Suenaga, Kazu; Stamatakis, Michail; Warner, Jamie H.; Tsang, Shik Chi Edman

2017-08-01

The conversion of oxygen-rich biomass into hydrocarbon fuels requires efficient hydrodeoxygenation catalysts during the upgrading process. However, traditionally prepared CoMoS2 catalysts, although efficient for hydrodesulfurization, are not appropriate due to their poor activity, sulfur loss and rapid deactivation at elevated temperature. Here, we report the synthesis of MoS2 monolayer sheets decorated with isolated Co atoms that bond covalently to sulfur vacancies on the basal planes that, when compared with conventionally prepared samples, exhibit superior activity, selectivity and stability for the hydrodeoxygenation of 4-methylphenol to toluene. This higher activity allows the reaction temperature to be reduced from the typically used 300 °C to 180 °C and thus allows the catalysis to proceed without sulfur loss and deactivation. Experimental analysis and density functional theory calculations reveal a large number of sites at the interface between the Co and Mo atoms on the MoS2 basal surface and we ascribe the higher activity to the presence of sulfur vacancies that are created local to the observed Co-S-Mo interfacial sites.
Spin conversion induced by the spin-orbit interaction in positronium collisions

International Nuclear Information System (INIS)

Saito, Haruo; Nakayama, Takashi; Hyodo, Toshio

2009-01-01

We show the existence of a new reaction mechanism of positronium - ortho-Ps - para-Ps conversion reaction induced by the spin-orbit interaction. This interaction was previously believed to be negligibly small. Recently, however, Mitroy has suggested that this interaction could be observed in Ps-Xe collision. In the present work, we have succeeded in observing this effect and obtaining the reaction rate by using the Zeeman mixing of positronium.
Molecular beam studies of reaction dynamics

International Nuclear Information System (INIS)

Lee, Yuan T.

1991-03-01

The major thrust of this research project is to elucidate detailed dynamics of simple elementary reactions that are theoretically important and to unravel the mechanism of complex chemical reactions or photochemical processes that play important roles in many macroscopic processes. Molecular beams of reactants are used to study individual reactive encounters between molecules or to monitor photodissociation events in a collision-free environment. Most of the information is derived from measurement of the product fragment energy, angular, and state distributions. Recent activities are centered on the mechanisms of elementary chemical reactions involving oxygen atoms with unsaturated hydrocarbons, the dynamics of endothermic substitution reactions, the dependence of the chemical reactivity of electronically excited atoms on the alignment of excited orbitals, the primary photochemical processes of polyatomic molecules, intramolecular energy transfer of chemically activated and locally excited molecules, the energetics of free radicals that are important to combustion processes, the infrared-absorption spectra of carbonium ions and hydrated hydronium ions, and bond-selective photodissociation through electric excitation
Molecular beam studies of reaction dynamics

Energy Technology Data Exchange (ETDEWEB)

Lee, Y.T. [Lawrence Berkeley Laboratory, CA (United States)

1993-12-01

The major thrust of this research project is to elucidate detailed dynamics of simple elementary reactions that are theoretically important and to unravel the mechanism of complex chemical reactions or photochemical processes that play important roles in many macroscopic processes. Molecular beams of reactants are used to study individual reactive encounters between molecules or to monitor photodissociation events in a collision-free environment. Most of the information is derived from measurement of the product fragment energy, angular, and state distributions. Recent activities are centered on the mechanisms of elementary chemical reactions involving oxygen atoms with unsaturated hydrocarbons, the dynamics of endothermic substitution reactions, the dependence of the chemical reactivity of electronically excited atoms on the alignment of excited orbitals, the primary photochemical processes of polyatomic molecules, intramolecular energy transfer of chemically activated and locally excited molecules, the energetics of free radicals that are important to combustion processes, the infrared-absorption spectra of carbonium ions and hydrated hydronium ions, and bond-selective photodissociation through electric excitation.
Reactivity and selectivity of arenes in reactions with ozone

International Nuclear Information System (INIS)

Vysotskii, Yu.B.; Mestechkin, M.M.; Sivyakova, L.N.; Tyupalo, N.F.

1987-01-01

The reactions of arenes with ozone, distinguished by the variety of products (quinones, aldehydes, acids), are of interest not only from the theoretical standpoint but also are of preparative value in the case of polycyclic hydrocarbons. In this work a quantitative treatment of this reaction is given on the basis of direct kinetic measurements and simple quantum chemical means, permitting its rate constants and the yield of the products to be related to the elements of electronic structure readily subject to quantum mechanical calculation
GC×GC measurements of C7-C11 aromatic and n-alkane hydrocarbons on Crete, in air from Eastern Europe during the MINOS campaign

Science.gov (United States)

Xu, X.; Williams, C.; Plass-Dülmer, H.; Berresheim, H.; Salisbury, G.; Lange, L.; Lelieveld, J.

2003-09-01

During the Mediterranean Intensive Oxidant Study (MINOS) campaign in August 2001 gas-phase organic compounds were measured using comprehensive two-dimensional gas chromatography (GCxGC) at the Finokalia ground station, Crete. In this paper, C7-C11 aromatic and n-alkane measurements are presented and interpreted. The mean mixing ratios of the hydrocarbons varied from 1±1 pptv (i-propylbenzene) to 43±36 pptv (toluene). The observed mixing ratios showed strong day-to-day variations and generally higher levels during the first half of the campaign. Mean diel profiles showed maxima at local midnight and late morning, and minima in the early morning and evening. Results from analysis using a simplified box model suggest that both the chemical sink (i.e. reaction with OH) and the variability of source strengths were the causes of the observed variations in hydrocarbon mixing ratios. The logarithms of hydrocarbon concentrations were negatively correlated with the OH concentrations integral over a day prior to the hydrocarbon measurements. Slopes of the regression lines derived from these correlations for different compounds are compared with literature rate constants for their reactions with OH. The slopes for most compounds agree reasonably well with the literature rate constants. A sequential reaction model has been applied to the interpretation of the relationship between ethylbenzene and two of its potential products, i.e. acetophenone and benzeneacetaldehyde. The model can explain the good correlation observed between [acetophenone]/[ethylbenzene] and [benzeneacetaldehyde]/[ethylbenzene]. The model results and field measurements suggest that the reactivity of benzeneacetaldehyde may lie between those of acetophenone and ethylbenzene and that the ratio between yields of acetophenone and benzeneacetaldehyde may be up to 28:1. Photochemical ages of trace gases sampled at Finokalia during the campaign are estimated using the sequential reaction model and related data
DC Thermal Plasma Design and Utilization for the Low Density Polyethylene to Diesel Oil Pyrolysis Reaction

Directory of Open Access Journals (Sweden)

Hossam A. Gabbar

2017-06-01

Full Text Available The exponential increase of plastic production produces 100 million tonnes of waste plastics annually which could be converted into hydrocarbon fuels in a thermal cracking process called pyrolysis. In this research work, a direct current (DC thermal plasma circuit is designed and used for conversion of low density polyethylene (LDPE into diesel oil in a laboratory scale pyrolysis reactor. The experimental setup uses a 270 W DC thermal plasma at operating temperatures in the range of 625 °C to 860 °C for a low density polyethylene (LDPE pyrolysis reaction at pressure = −0.95, temperature = 550 °C with τ = 30 min at a constant heating rate of 7.8 °C/min. The experimental setup consists of a vacuum pump, closed system vessel, direct current (DC plasma circuit, and a k-type thermocouple placed a few millimeters from the reactant sample. The hydrocarbon products are condensed to diesel oil and analyzed using flame ionization detector (FID gas chromatography. The analysis shows 87.5% diesel oil, 1,4-dichlorobenzene (Surr, benzene, ethylbenzene and traces of toluene and xylene. The direct current (DC thermal plasma achieves 56.9 wt. % of diesel range oil (DRO, 37.8 wt. % gaseous products and minimal tar production. The direct current (DC thermal plasma shows reliability, better temperature control, and high thermal performance as well as the ability to work for long operation periods.
Bioremediation of soils containing petroleum hydrocarbons, chlorinated phenols, and polycyclic aromatic hydrocarbons

International Nuclear Information System (INIS)

Seech, A.; Burwell, S.; Marvan, I.

1994-01-01

Bench-scale treatability investigations, pilot-scale and full-scale bioremediation projects were conducted to evaluate Daramend trademark bioremediation of soils containing petroleum hydrocarbons, heavy oils, paraffins, chlorinated phenols and polycyclic aromatic hydrocarbons (PAHs). Bench-scale investigations were conducted using glass microcosms. Pilot-scale and full-scale demonstrations were conducted at industrial sites and included treatment of excavated soils and sediments in on-site cells constructed using synthetic liners and covered by steel/polyethylene structures as well as in-situ treatment. A total of approximately 5,000 tons of soil was treated. The soil treatment included organic soil amendments, specialized tillage/aeration apparatus, and strict control of soil moisture. The amendments are composed of naturally-occurring organic materials prepared to soil-specific particle size distributions, nutrient profiles, and nutrient-release kinetics. Bench-scale work indicated that in refinery soil containing high concentrations of heavy oils, extractable hydrocarbon concentrations could be rapidly reduced to industrial clean-up criteria, and that the hydrocarbons were fully mineralized with release of CO 2
Simulation codes to evcaluate dose conversion coefficients for hadrons over 10 GeV

International Nuclear Information System (INIS)

Sato, T.; Tsuda, S.; Sakamoto, Y.; Yamaguchi, Y.; Niita, K.

2002-01-01

The conversion coefficients from fluence to effective dose for high energy hadrons are indispensable for various purposes such as accelerator shielding design and dose evaluation in space mission. Monte Carlo calculation code HETC-3STEP was used to evaluate dose conversion coefficients for neutrons and protons up to 10 GeV with an anthropomorphic model. The scaling model was incorporated in the code for simulation of high energy nuclear reactions. However, the secondary particle energy spectra predicted by the model were not smooth for nuclear reactions over several GeV. We attempted, therefore, to simulate transportation of such high energy particles by two newly developed Monte Carlo simulation codes: one is HETC-3STEP including the model used in EVENTQ instead of the scaling model, and the other is NMTC/JAM. By comparing calculated cross sections by these codes with experimental data for high energy nuclear reactions, it was found that NMTC/JAM had a better agreement with the data. We decided, therefore, to adopt NMTC/JAM for evaluation of dose conversion coefficients for hadrons with energies over 10 GeV. The effective dose conversion coefficients for high energy neutrons and protons evaluated by NMTC/JAM were found to be close to those by the FLUKA code
Characterization of hydrocarbon utilizing fungi from hydrocarbon ...

African Journals Online (AJOL)

Prof. Ogunji

isolated fungi could be useful in the bioremediation of hydrocarbon polluted sites. Keywords: ... Technologies such as mechanical force, burying, evaporation, dispersant application, and ..... The effects of drilling fluids on marine bacteria from a.
Delta-electron spectroscopy: An aid for the determination of reaction times in heavy ion reactions

International Nuclear Information System (INIS)

Skapa, H.

1983-01-01

For the systems I->Au and I->Bi at an incident energy of 6.2 MeV/u (I->Au) and 6.6 MeV/u (I->Bi) the emission probability of delta electrons was determined. In an energy range from 150 KeV to 1000 KeV electrons were spectroscoped in coincidence to elastically, quasielastically, and deep inelastically scattered ions. In deep inelastic reaction between reaction products with high and without a mean mass drift was discriminated. The contribution of the conversion electrons, determined from gamma spectra, extends in the range of deep inelastic reactions of about 60%. While the ratio of conversion electrons for deep inelastic events with large to such without mass drift shows a flat, monotoneous growth for the ratio of the measured emission probabilities a oscillation-like structure with about 400 KeV width results. An interpretation of this structure as interference effect by nuclear time delay yields for the case of large mass drift a nuclear retention time of 7.5 x 10 -21 s. (orig./HSI) [de
Determination of 15 polycyclic aromatic hydrocarbons in aquatic products by solid-phase extraction and GC-MS.

Science.gov (United States)

Liu, Qiying; Guo, Yuanming; Sun, Xiumei; Hao, Qing; Cheng, Xin; Zhang, Lu

2018-02-22

We propose a method for the simultaneous determination of 15 kinds of polycyclic aromatic hydrocarbons in marine samples (muscle) employing gas chromatography with mass spectrometry after saponification with ultrasound-assisted extraction and solid-phase extraction. The experimental conditions were optimized by the response surface method. In addition, the effects of different lyes and extractants on polycyclic aromatic hydrocarbons extraction were discussed, and saturated sodium carbonate was first used as the primary saponification reaction and extracted with 10 mL of ethyl acetate and secondly 1 mol/L of sodium hydroxide and 10 mL of n-hexane were used to achieve better results. The average recovery was 67-112%. Satisfactory data showed that the method has good reproducibility with a relative standard deviation of <13%. The detection limits of polycyclic aromatic hydrocarbons were 0.02-0.13 ng/g. Compared with other methods, this method has the advantages of simple pretreatment, low solvent consumption, maximum polycyclic aromatic hydrocarbons extraction, the fast separation speed, and the high extraction efficiency. It is concluded that this method meets the batch processing requirements of the sample and can also be used to determine polycyclic aromatic hydrocarbons in other high-fat (fish, shrimp, crab, shellfish) biological samples. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Measuring Trace Hydrocarbons in Silanes

Science.gov (United States)

Lesser, L. A.

1984-01-01

Technique rapid and uses standard analytical equipment. Silane gas containing traces of hydrocarbons injected into carrier gas of moist nitrogen having about 0.2 percent water vapor. Carrier, water and silane pass through short column packed with powdered sodium hydroxide which combines moisture and silane to form nonvolatile sodium silicate. Carrier gas free of silane but containing nonreactive hydrocarbons, pass to silica-gel column where chromatographic separation takes place. Hydrocarbons measured by FID.
Sequential Condensation and Hydrodeoxygenation Reaction of Furfural-Acetone Adduct over Mix Catalysts Ni/SiO2 and Cu/SiO2 in Water

Directory of Open Access Journals (Sweden)

Siti Mariyah Ulfa

2018-05-01

Full Text Available Sequential condensation and hydrodeoxygenation reaction were perform using autoclave batch reactor in the presence of water as a solvent. The condensation of furfural and acetone was performed using MgO catalyst followed by hydrodeoxygenation using mix catalyst Ni/SiO2 and Cu/SiO2. The catalyst was prepared by wet-impregnation method and analyzed by XRD, SEM-EDX as well as BET surface. Condensation of furfural and acetone in 1:2 mol ratio was carried out by reflux gave 4-(2-furyl-3-buten-2-one and 1,5-bis-(2-furanyl-1,4-pentadien-3-one. The condensation product was then subjected for hydrodeoxygenation using batch reactor, catalyzed by mixed Ni/SiO2 and Cu/SiO2 at 150 and 180 °C for 2 h. The product identified as alkane derivatives with the conversion at 38.83 and 50.35%, respectively. The selectivity of hydrocarbon is 61.39% at 150 °C and 16.55% at 180 °C. Increasing the reaction temperature to 200 °C did not give any products except the recovery of the precursor. It showed that higher temperature enhanced the catalyst activity but the selectivity is controlled by low reaction temperature.
Process systems engineering issues and applications towards reducing carbon dioxide emissions through conversion technologies

DEFF Research Database (Denmark)

Roh, Kosan; Frauzem, Rebecca; Gani, Rafiqul

2016-01-01

This paper reviews issues and applications for design of sustainable carbon dioxide conversion processes, specifically through chemical conversion, and the integration of the conversion processes with other systems from a process systems engineering (PSE) view-point. Systematic and computer......-aided methods and tools for reaction network generation, processing route generation, process design/optimization, and sustainability analysis are reviewed with respect to carbon dioxide conversion. Also, the relevant gaps and opportunities are highlighted. In addition, the integration of carbon dioxide...

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