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Catalysis and Reaction Engineering Commons™

Open Access. Powered by Scholars. Published by Universities.®

1998

Articles 1 - 25 of 25

Full-Text Articles in Catalysis and Reaction Engineering

Oxygen Transfer In A Three-Phase Fluidised Bed Bioreactor With Novel Biomass Support When Used In Industrial Wastewater Treatment, S Manyele, Dec 1998

Oxygen Transfer In A Three-Phase Fluidised Bed Bioreactor With Novel Biomass Support When Used In Industrial Wastewater Treatment, S Manyele,

Tanzania Journal of Engineering and Technology (TJET)

The effect of support mass and liquid height on the oxygen transfer in the three- phase fluidised bed were experi/nenta/ly investigated. Novel biomass support, rhe KMT*, with density of 850 kg/n/ and an equivalent size, dp 8.3 mm, has been used in this work. The oxygen transfer rate was expressed in terms of rhe volumetric oxygen transfer coefficient, kca. It has been found out that the* a values increased with increasing support mass up to a critical solids load of 4.0 kg, above which the kca decreased and that kca decreased with increasing liquid height. It has been recommended that …

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Turbulent Burning Model For Premixed Gaseous Mixtures, E Mushi Dec 1998

Turbulent Burning Model For Premixed Gaseous Mixtures, E Mushi

Tanzania Journal of Engineering and Technology (TJET)

A turbulent burning model for premixed gaseous mixtures has been successfully developed. The model assumes instant burning of vortex Tubes of the order of Kolmogorov scale followed by burning of larger eddies of the order of Taylor micro scale. These eddies burn ar a rate dependent On the stretch rate. The influence of turbulence on the burning rate is introduced in the form of probability density function which gives the probability that a given mixture under turbulence will undergo burning rather than being quenched. The model has been validated againsi experiments involving turbulent explosions in a fan stirred bomb. Model …

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New Technologies For Thermal Disposal Of Sewage Sludge, T Ogada Dec 1998

New Technologies For Thermal Disposal Of Sewage Sludge, T Ogada

Tanzania Journal of Engineering and Technology (TJET)

The traditional methods for the disposal of sewage sludge are landfilling, recycling as fertilisers in agricultural lands, dumping into sea and incineration. In thc recent past, Sludge incineration has been rapidly gaining ground duc to environmental constraints facing the Other methods. However, the cost of pollution control during sewage sludge incineration is currently very high due to the expensive flue gas treatment facility required. Futhermore, large quantity Of ash is produced which is highly contaminated with heavy metals and must be disposed off in special landfilling sites in order to avoid ground water pollution. To reduce the cost Of pollution …

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Experimental Study Of Domestic Charcoal Stoves, Simbo Kimario Dec 1998

Experimental Study Of Domestic Charcoal Stoves, Simbo Kimario

Tanzania Journal of Engineering and Technology (TJET)

The demand of fuelwood for domestic cooking especially the charcoal fuel is increasing in the urban settlements due to the increase in population of low income class earners who are the main consumers Of this type of fuel. This paper is presenting rhe results Of experiments conducted on the popularly used domestic charcoal stoves in Tanzania. The results revealed some significant differences on stoves performances. The type of insulation materials and some design features incorporated into the combustion chambers of the stoves had positive impacts in relative charcoal fuel saving. About two tons of charcoal fuel could be saved by …

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The Significance And Effects Of Oil Injection On The Performance Of Sliding Vane Compressors., M Mkumbwa Dec 1998

The Significance And Effects Of Oil Injection On The Performance Of Sliding Vane Compressors., M Mkumbwa

Tanzania Journal of Engineering and Technology (TJET)

A computer model of a sliding vane air compressor was used to predict the behaviour of machines having different geometries operating at different conditions. The performance parameters which were calculated by the model were the free air delivery, power input and specific capacity which is defined as the free air delivery per unit of power input.The model also included the study of the effects of Oil injection on these mentioned compressor performance parameters. The paper describes the simulation model developed incorporating an analysis Of the effects of the oil injected into the compressor on lhe thermodynamic processes taking place in …

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A Study On Ring Pack Lubrication In Internal Combustion Engine, I Mshoro Dec 1998

A Study On Ring Pack Lubrication In Internal Combustion Engine, I Mshoro

Tanzania Journal of Engineering and Technology (TJET)

Most efthe lubricating oil from Internal Combustion Engine (ICE) is lost through piston rings. Hence, in order to optimally reduce ICE oil consumption, a better insight into tribology of the ring pack is required. This can only be achieved by an inwroved characterization of the lubricant behaviour within the opelating environment of the engine. In The present ieork, an optical tcchnique using laser- induced fluorescence was employed to measure oil film thickness within the ring pack. The experiment was conducted on a Phaser 1000 Series engine, whereby optical access to the ring pack was achieved by a fused silica-window positioned …

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The Latest World Wide Progress In Solid Oxide Fuel Cell, Yi Jiang Nov 1998

The Latest World Wide Progress In Solid Oxide Fuel Cell, Yi Jiang

Journal of Electrochemistry

Solid oxide fuel cell (SOFC) is a novel, green electricity generation technology, which has been showing rapid development since 1980's. In light of its high efficiency, environmental friendly, fuel adaptability and long term stability, the Research, Development and Demonstration (RD&D) of this hype of full cell have been emphasized in a large number of developed countries. Based on the information communicated at the latest symposium on SOFC held last year in Aachen (Germany) and the knowledge gained through years of research in this field, a comprehensive review on the latest development of the tubular, this planar SOFC as well as …

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A Preliminary Study Of The Synthesis Of Tin-Based Amorphous Material And Its Behavior On Lithium Intercalation, Li Liu, Han-Xi Yang, Ju-Tang Sun, Xing-Ping Ai Nov 1998

A Preliminary Study Of The Synthesis Of Tin-Based Amorphous Material And Its Behavior On Lithium Intercalation, Li Liu, Han-Xi Yang, Ju-Tang Sun, Xing-Ping Ai

Journal of Electrochemistry

An amorphous lithium inserting anode material based on Tin oxide glass was synthesized by salification in solution and its properties on lithium intercalation was investigated by X ray diffraction (XRD), microelectrode voltammetry and charge discharge measurements. The results have shown that this kind of material has considerable electrochemical reversibility toward lithium intercalation deintercalation. The available discharge capacity of the material reaches 430 mAh/g with charge-discharge efficiency over 90%, showing a great potential for practical use.

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Direct Electro-Oxidation Synthesis Of D-Arabinose On Spectroscopic Graphite Electrode, Hei Wei, Huang Ying Nov 1998

Direct Electro-Oxidation Synthesis Of D-Arabinose On Spectroscopic Graphite Electrode, Hei Wei, Huang Ying

Journal of Electrochemistry

D Arabinose synthesized by direct electro-oxidative decarboxylation of D gluconate on graphite electrode from aqueous solutions. The effects of D gluconate concentration, electrolysis potential, temperature and electrolyte composition on the current efficiency and product yield of electrosynthsis are discussed. The laboratory scale electrosynthesis was achieved with flow through cell. The optimum technology conditions for electrosynthesis were obtained with orthogonal design method. Both galvanostatic and potentionstatic conditions have been exploited, the later was found to be more effective.

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Study On Electrosynthesis Of Butyl Butyrate At Conducting Oxide Anode Support On Titanium, Jun-Xiang He, Jin-Cheng Zhou, Kang-Ning Chen Nov 1998

Study On Electrosynthesis Of Butyl Butyrate At Conducting Oxide Anode Support On Titanium, Jun-Xiang He, Jin-Cheng Zhou, Kang-Ning Chen

Journal of Electrochemistry

Synthesis of butyl butyrate by direct electroxidation of n butyl alcohol and the electrochemical behaviors of several selected conducting oxide electrodes (Pb/PbO2, Ti/PbO2, i/SnO2+Sb2O3/PbO2 and Ti/SnO2+Sb2O3+PdOx/PbO2) have been investigated. The results demonstrated that the intermediate layers of SnO2, Sb2O3 and PdOx could significantly decrease the interfacial resistance of the electrodes, and that the Ti/SnO2+Sb2O3+PdOx/PbO2 electrode possessed better electrocatelytic performance than others.

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Primary Research Of Reversible Proton Exchange Membrane Regenerative Fuel Cells, Zhi-Gang Shao, Bao-Lian Yi, Ming Han Nov 1998

Primary Research Of Reversible Proton Exchange Membrane Regenerative Fuel Cells, Zhi-Gang Shao, Bao-Lian Yi, Ming Han

Journal of Electrochemistry

In this paper, we report the results of our studies on regenerative proton exchange membrane fuel cell (RPEMRFC) catalysts, electrode preparation and their performances. The Pt catalyst for the oxygen electrode was replaced by 60 w%Pt + 40 w%IrO2 which reduces polarization by 0.2 V in a polymer protone exchange membrane fuel cell. The cycle performance of RPEMRFC was found to be manly effected by the stability of the diffiusion layer of bifunctional oxygen electrode.

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Direct Electrochemical Reaction Of Cytochrome C At The Poly (Ethylene Oxide) Film Modified Gold Electrodes, Xiao-Gang Qu, Gong-Quan Sun, Hui Yang, Tian-Hong Lu Aug 1998

Direct Electrochemical Reaction Of Cytochrome C At The Poly (Ethylene Oxide) Film Modified Gold Electrodes, Xiao-Gang Qu, Gong-Quan Sun, Hui Yang, Tian-Hong Lu

Journal of Electrochemistry

In this paper, the direct electrochemical reaction of cytochrome c was sudied at the poly (ethylene oxide) film modified gold electrodes. It was found the PEO is a good promoter for the electrochemical reaction of cytochrome c, and the reversibility of reaction of cytochrome c was found to depend on the molecular weight of PEO and the morphology of the PEO films.

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Studies On The Electrode Kinetics Of Electrooxidation Of Mn2+, Wan-Li Hu, Tong Su, Wei Guo, Ding Zhou Aug 1998

Studies On The Electrode Kinetics Of Electrooxidation Of Mn2+, Wan-Li Hu, Tong Su, Wei Guo, Ding Zhou

Journal of Electrochemistry

The mechanism of electrooxidation of MnSO4 on Pb Sb As alloy anode was investigated by using rotating disc electrode technique. The results shown that the conditional standard potential of Mn(Ⅲ)/Mn(Ⅱ)in 40% H2SO4 is 0.886 4 V.The rate controlling step of electrode process is mixed controlled by charge transfer and diffusion.

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Study Of Proton Exchange Membrane Fuel Cells(Pemfc), Shan-Hai Ge, Bao-Lian Yi, Hong-Fen Xu, Ming Han, Zhi-Gang Shao Aug 1998

Study Of Proton Exchange Membrane Fuel Cells(Pemfc), Shan-Hai Ge, Bao-Lian Yi, Hong-Fen Xu, Ming Han, Zhi-Gang Shao

Journal of Electrochemistry

The electrode kinetic parameters for proton exchange membrane fuel cells(PEMFC) were investigated by measuring the relations of cell potential and current density. An experimental stack of PEMFC which can be operated at E cell =0.7V, I =0.55A/cm2 steadily is presented, and the effects of electrode structure and operation conditions such as temperature, pressure, humidification, flow rate on the performance of PEMFC are discussed.

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Electrooxidation Of Benzene To Benzoquinone In A Packed Bed Reactor, Xin-Sheng Zhang, Ping Ding, Ying-Chun Dai, Wei-Kang Yuan Aug 1998

Electrooxidation Of Benzene To Benzoquinone In A Packed Bed Reactor, Xin-Sheng Zhang, Ping Ding, Ying-Chun Dai, Wei-Kang Yuan

Journal of Electrochemistry

A packed electrode reactor was used to oxidize to benzoquinone. Anode bed of the reactor has a size of 10～30 mm×450 mm×50 mm(thickness×length×width),and was packed porous lead alloy. A dispersion of benzene in 1 mol/L aqueous sulfuric acid was passed through the reactor. Current efficiency for benzoquinone generation is 62.9% at optimal operating condition: velocity of electrolyte flow, 0.19 ms -1 ;current, 10 A; thickness of anode bed, 10 mm, and percentage of benzene, 24%.

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Design Considerations For A Three-Phase Fluidized-Bed Bioreactor, S Manyele Jun 1998

Design Considerations For A Three-Phase Fluidized-Bed Bioreactor, S Manyele

Tanzania Journal of Engineering and Technology (TJET)

The design Of a three-phase fluidized bed bioreactor using novel biomass support for industrial wastewater treatment is reported in this paper. A column of 0.20 m diameter with variable height up to 6.60 m equipped with a foam breaker tank was designed, commissioned and operated. A novel biomass support, KMTR support, has been used Separate gas and liquid feeding systems were designed to facilitate proper bioreactor operation. A flat distriburor plate with 4 mm holes- diameter was desined A study on the hydrodynamic properties of the three-phase fluidized bed bioreactor revealed high values of bed expansion and air hold-ups. Purification …

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Use Of Dissolved Oxygen Concentration Probes In Biological Wastewater Treatment Plants, S Manyele Jun 1998

Use Of Dissolved Oxygen Concentration Probes In Biological Wastewater Treatment Plants, S Manyele

Tanzania Journal of Engineering and Technology (TJET)

A study on use Of dissolved oxygen probes (DOP) for measurement Of oxygen concentration in warer and wastewater treatment is presented. The principles Of operation, design considerations and selection criteria for Two types of probes, viz. galvanic and polarographic, are discussed Use of polarographic probes in n rhree-phase fluidized bed bioreactor and in laboratory experiments is presented and discussed. The effect of airflow rate and treatment time on dissolved oxygen concentration was found to be significant. It was found that polarographic probes are important equipment in determining the pollution of the industrial effluents. Finally, the use of the DOC probes …

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In-Situ Raman Spectroscopic Study Of The Oxidation And Reduction Of Ag Electrode In Na2So4, Yan-Xia Chen, Kai-Qi Huang, Zhong-Qun Tian May 1998

In-Situ Raman Spectroscopic Study Of The Oxidation And Reduction Of Ag Electrode In Na2So4, Yan-Xia Chen, Kai-Qi Huang, Zhong-Qun Tian

Journal of Electrochemistry

In-situ Raman spectroscopy combined with cyclic voltammogram measurements was used to investigate formation of oxygen species at Ag electrode surfaces during the oxidation and reduction process in 0.1 mol/L Na2SO4 solution. The time dependent Raman spectra show that at potentials positive of 0.2 V, adsorption of oxygen atom occurs, while at the potentials positive of 0.4 V, some oxygen atoms migrate into subsurface of the Ag electrode and the other form strongly bound oxygen on the surface through chemical bond. At the same potentials, part of the silver atoms are oxidized and form Ag2SO4 …

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Studies Of Surface Alloy As High Efficient Electrocatalyst For Glyoxylic Acid Synthesis, Sheng-Pei Chen, Sheng-Qing Xia, Shi-Gang Sun May 1998

Studies Of Surface Alloy As High Efficient Electrocatalyst For Glyoxylic Acid Synthesis, Sheng-Pei Chen, Sheng-Qing Xia, Shi-Gang Sun

Journal of Electrochemistry

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Studies Of Surface Electrochemistry And Electrocatalysis At Atomic And Molecule Level, Shigang Sun Feb 1998

Studies Of Surface Electrochemistry And Electrocatalysis At Atomic And Molecule Level, Shigang Sun

Journal of Electrochemistry

The main progresses achieved during last few years in our research group concerning studies of surface electrochemistry and electrocatalysis were reviewed in this present paper. Four topics were described: 1) the surface electrochemistry and model electrocatalysis of metal single crystal planes, 2) the electrocatalytic reaction mechanism and the control of reaction pathways at molecule level, 3) the reaction kinetics of electrooxidation of small organic molecules, and 4) the relationship between the properties and the surface chemical states of electrocatalyst. This review lays in emphasis on the demonstration of the results as well as the research direction of surface electrochemistry and …

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Study On The Synthesis And Electrochemical Behavior Of Poly (Quinonoid-Disulfide), Xiaohui Tang, Xiuwu Sun, Yongfang Li, Shibi Fang Feb 1998

Study On The Synthesis And Electrochemical Behavior Of Poly (Quinonoid-Disulfide), Xiaohui Tang, Xiuwu Sun, Yongfang Li, Shibi Fang

Journal of Electrochemistry

Organic polydisulfide containing quinonoid structure was synthesized by chloromethylation, oxidation by nitric acid, and condensation polymerization with sodium disulfide. The effect of quinonoid structure on the electrochemical behavior of organic polydisulfide was investigated with cyclic voltammetry and chargedischarge measurement. The result shows that quinonoid struture mainly affects the positions of redox peaks of organic polydisulfide, open circuit voltage and discharge platform voltage of cell with the organic polydisulfide as cathode.

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The Investigations Of Surface Treatment Methods And Characterization Of Oxide Films On Ab5 Based Metal Hydride Electrodes Ⅰ. New NiRich Treatment Methods And Photoelectrochemical Characterization Of Oxide Films, Junmin Nan, Yong Yang, Jun Li, Zugeng Lin Feb 1998

The Investigations Of Surface Treatment Methods And Characterization Of Oxide Films On Ab5 Based Metal Hydride Electrodes Ⅰ. New NiRich Treatment Methods And Photoelectrochemical Characterization Of Oxide Films, Junmin Nan, Yong Yang, Jun Li, Zugeng Lin

Journal of Electrochemistry

Two simple and efficient surface treatment methods for AB5 type hydrogen storage alloys were developed. The results of X-ray photoelectron spectroscopy (XPS) and cyclic voltammetric (CV) experiments showed that the hydrogen storage alloys treated by two different methods had Ni rich surface layer so that the performances of the electrodes were improved after treatment. The characterization of the oxide films which formed on the surface of electrodes through potentiodynamic oxidation with the help of photoelectrochemical microscopy (PEM) were done. The anodic photocurrent and the cathodic photocurrent related to the oxidation of hydrogen and the reduction of oxygen on the …

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A Study On Heterogeneous Indirect Electrosynthesis Of Benzaldehyde, Daobao Chu, Changjian Lin, Huashui Lin, Jianguang Tan Feb 1998

A Study On Heterogeneous Indirect Electrosynthesis Of Benzaldehyde, Daobao Chu, Changjian Lin, Huashui Lin, Jianguang Tan

Journal of Electrochemistry

Heterogeneous indirect electrosynthesis process of benzaldehyde has been investigated using cyclic voltammetry and polarization curves. An optimum condition for preparation of benzaldehyde by indirect electrooxidation of toluenc with redox Mn3+/Mn2+ is given in this paper. Electrolytic regeneration Mn3+ are made at Pt/Ti anode in “slurry” MnSO4/H2SO4 medium. Current efficiency for electrolytic regeneration Mn3+  was maintained over 88% by “double cyclic way”.

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Investigation Of Methanol Anode Electrooxidation Catalysts, Gangyao Wen, Ying Zhang, Zhenglong Yang, Changzhi Li Feb 1998

Investigation Of Methanol Anode Electrooxidation Catalysts, Gangyao Wen, Ying Zhang, Zhenglong Yang, Changzhi Li

Journal of Electrochemistry

A series of catalysts, Pt-WO3/C, Pt/Ru/C and Pt-Ru-WO3/C were prepared by chemical reduction deposition. Electrocatalytic oxidation of methanolon different catalyst/Nafion membrane electrodes was studies by voltammetry and current-potential polarization. The results indicated that the catalytic activity order of different catalysts is as follows: Pt-Ru-WO3/C > Pt-Ru/C > Pt-WO3/C. At the same time, influences of methanol concentrations and catalyst proportion on performances of anodes were also studies.

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Progresses In Surface Electrochemistry And Electrocatalysis ——A Review On The 1997 Joint International Meeting Of Electrochemistry And 97' International Meeting Of Surface Electrochemistry, Shigang Sun Feb 1998

Progresses In Surface Electrochemistry And Electrocatalysis ——A Review On The 1997 Joint International Meeting Of Electrochemistry And 97' International Meeting Of Surface Electrochemistry, Shigang Sun

Journal of Electrochemistry

The progresses in surface electrochemistry and electrocatalsis reported in the 1997 joint international meeting of electrochemistry and in the 97′ international meeting of surface electrochemistry were reviewed. The main trends described in this paper consisted of 7 aspects: 1) the studies employing single crystal electrodes, 2) the development of in situ methods of diverse spectroscpoy, 3) the innovation of new research techniques, 4) the preparaton of electrocatalyst of high performances, 5) the quantitative studies on kinetics of electrocatalytic reactions, 6) the investigation on the dynamic processes of surface by timeresolved methods, and 7) the theoretical modeling and simulation of surface …

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