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Chemical and Biochemical Engineering Faculty Research & Creative Works

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Articles 571 - 600 of 823

Full-Text Articles in Chemical Engineering

On One-Dimensional Self-Assembly Of Surfactant-Coated Nanoparticles, Jee-Ching Wang, Partho Neogi, Daniel Forciniti Nov 2006

On One-Dimensional Self-Assembly Of Surfactant-Coated Nanoparticles, Jee-Ching Wang, Partho Neogi, Daniel Forciniti

Chemical and Biochemical Engineering Faculty Research & Creative Works

Nanometer-sized metal and semiconductor particles possess novel properties. To fully realize their potential, these nanoparticles need to be fabricated into ordered arrays or predesigned structures. A promising nanoparticle fabrication method is coupled surface passivation and self-assembly of surfactant-coated nanoparticles. Due to the empirical procedure and partially satisfactory results, this method still represents a major challenge to date and its refinement can benefit from fundamental understanding. Existing evidences suggest that the self-assembly of surfactant-coated nanoparticles is induced by surfactant-modified interparticle interactions and follows an intrinsic road map such that short one-dimensional (1D) chain arrays of nanoparticles occur first as a stable …

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Magnetic Nanoparticle Supported Catalyst For Atom Transfer Radical Polymerization, Shijie Ding, Yangchuan Xing, Maciej Radosz, Youqing Shen Sep 2006

Magnetic Nanoparticle Supported Catalyst For Atom Transfer Radical Polymerization, Shijie Ding, Yangchuan Xing, Maciej Radosz, Youqing Shen

Chemical and Biochemical Engineering Faculty Research & Creative Works

Magnetic nanoparticles were used to support an ATRP catalyst for the polymerization of methyl methacrylate (MMA) for minimized adverse effect of catalyst support and easy catalyst separation. the nanoparticle-supported catalyst mediated a living/controlled radical polymerization of MMA as effectively as unsupported catalysts. with the addition of 22 mol % of CuBr 2, the polymer molecular weights were well-controlled with an initiator efficiency of 0.85 and polydispersity lower than 1.2. the supported catalysts could be easily separated/isolated using an external magnetic field and reused with slightly decreased activity but further improved control. the activity of the recycled catalyst was regenerated by …

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Electrochemical Durability Of Carbon Nanotubes In Noncatalyzed And Catalyzed Oxidations, Liang Li, Yangchuan Xing Sep 2006

Electrochemical Durability Of Carbon Nanotubes In Noncatalyzed And Catalyzed Oxidations, Liang Li, Yangchuan Xing

Chemical and Biochemical Engineering Faculty Research & Creative Works

Noncatalyzed and catalyzed electrochemical oxidations of multiwalled carbon nanotubes (CNTs) were studied with the aim to understand their durability as catalyst support in polymer electrolyte membrane (PEM) fuel cells. Bare and Pt-deposited CNTs were investigated in 1.0 M sulfuric acid at a constant potential of 1.2 V. Carbon black (CB, Vulcan XC-72R) was also studied under the same experimental conditions. the carbons were oxidized at room temperature in the form of thin-film electrodes with time durations up to 48 h. Cyclic voltammetry was used to monitor the surface oxide redox reactions as a way to quantify the degree of surface …

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Influence Of Two Changes In The Composition Of An Acrylic Bone Cement On Some Of Its Properties: The Case Of Surgical Simplex® P, S. Madigan, Mark R. Towler, G. Lewis Sep 2006

Influence Of Two Changes In The Composition Of An Acrylic Bone Cement On Some Of Its Properties: The Case Of Surgical Simplex® P, S. Madigan, Mark R. Towler, G. Lewis

Chemical and Biochemical Engineering Faculty Research & Creative Works

Influence of two changes in the composition of a self-curing acrylic bone cement on some of its properties are discussed. Acrylic bone cements are widely used in orthopedic surgery for the fixation of joint prosthesis and in vertebroplasty and kyphoplasty for the stabilization and augmentation of fractured vertebrae. The cement's curing process is the result of a free-radical polymerization of a mixture of poly (methyl 1 methacrylate) [PMMA] containing powder and a liquid monomer that has methyl methacrylate (MMA) in it. It is initiated by the decomposition of benzoyl peroxide (BPO) in the powder, activated by a tertiary amine in …

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Flow Regime Identification In A Bubble Column Based On Both Statistical And Chaotic Parameters Applied To Computed Tomography Data, Stoyan Nedeltchev, Ashfaq Shaikh, Muthanna H. Al-Dahhan Sep 2006

Flow Regime Identification In A Bubble Column Based On Both Statistical And Chaotic Parameters Applied To Computed Tomography Data, Stoyan Nedeltchev, Ashfaq Shaikh, Muthanna H. Al-Dahhan

Chemical and Biochemical Engineering Faculty Research & Creative Works

The Kolmogorov Entropy (KE) Algorithm Was Applied Successfully to Single Source Γ-Ray Computed Tomography (CT) Data Measured in a 0.162 M ID Bubble Column Equipped with a Perforated Plate Distributor (163 Holes · Ø 1.32 Mm). Dried Air Was Used as the Gas Phase and Therminol LT (ΡL = 886 Kg M-3, ΜL = 0.88 · 10-3 Pa S, Σ = 17 · 10-3 N M-1) Was Used as a Liquid Phase. Three Different Pressures, P, of 0.1, 0.4, and 1.0 MPa Were Examined. at Each Pressure the Superficial Gas Velocity, UG, Was Increased Stepwise by Steps of 0.01 Ms-1 …

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The Influence Of Ultrasonic Setting On Fluoride Release From Glass Polyalkenoate Cements, N. Rushe, Mark R. Towler Sep 2006

The Influence Of Ultrasonic Setting On Fluoride Release From Glass Polyalkenoate Cements, N. Rushe, Mark R. Towler

Chemical and Biochemical Engineering Faculty Research & Creative Works

The effects of ultrasonic setting on fluoride release from glass polyalkenoate cements (GPC) were investigated. Cements based on two different aluminosilicate glasses that contained silica, alumina, phosphate, and strontia were used for the experiment. A series of GPCs were examined to show that increased release F- ion occurs, regardless of GPC composition. The results show that there is a greater release of fluoride from the ultrasonically set samples than those set chemically, regardless of the chemical composition. The snap set caused by the ultrasound is likely to be due to a combination of cavitation, improved mixing of the constituents, …

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Calcium And Zinc Ion Release From Polyalkenoate Cements Formed From Zinc Oxide/Apatite Mixtures, Mark R. Towler, S. Kenny, D. Boyd, T. Pembroke, M. Buggy, A. Guida, R. G. Hill Sep 2006

Calcium And Zinc Ion Release From Polyalkenoate Cements Formed From Zinc Oxide/Apatite Mixtures, Mark R. Towler, S. Kenny, D. Boyd, T. Pembroke, M. Buggy, A. Guida, R. G. Hill

Chemical and Biochemical Engineering Faculty Research & Creative Works

Calcium and zinc ion release from hydroxyapatite-zinc oxide-poly (acrylic acid) (HAZnO-PAA) composite cements into deionised water was investigated as a function of HA content, PAA concentration, PAA molecular weight and maturation time. At any given maturation time, zinc ion release was constant until the HA content was at the maximum loading (60 wt%) resulting in the cement matrix breaking up, allowing exacerbated ion release. The calcium ion release increased with increased HA content in the composite until the maximum loading where the release drops off. Up to this point, the release of both ionic species was proportional to square root …

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The Antibacterial Effects Of Zinc Ion Migration From Zinc-Based Glass Polyalkenoate Cements, D. Boyd, H. Li, D. A. Tanner, Mark R. Towler, J. G. Wall Jun 2006

The Antibacterial Effects Of Zinc Ion Migration From Zinc-Based Glass Polyalkenoate Cements, D. Boyd, H. Li, D. A. Tanner, Mark R. Towler, J. G. Wall

Chemical and Biochemical Engineering Faculty Research & Creative Works

Zinc-based glass polyalkenoate cements have been synthesised and their potential use in orthopaedic applications investigated. Zinc ions were released from the materials in a rapid burst over the first 24 h after synthesis, with the release rate falling below detectable levels after 7 days. Cement-implanted bone samples were prepared, and the released zinc was shown, using energy dispersive X-ray analysis, to penetrate from the cement into the adjacent bone by up to 40 μm. Finally, the cements exhibited antibacterial activity against Streptococcus mutans and Actinomyces viscosus that reflected the pattern of zinc release, with the inhibition of growth greatest shortly …

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Methane Production In A 100-L Upflow Bioreactor By Anaerobic Digestion Of Farm Waste, Abhijeet P. Borole, K. Thomas Klasson, Whitney Ridenour, Justin Holland, Khursheed Karim, Muthanna H. Al-Dahhan Jun 2006

Methane Production In A 100-L Upflow Bioreactor By Anaerobic Digestion Of Farm Waste, Abhijeet P. Borole, K. Thomas Klasson, Whitney Ridenour, Justin Holland, Khursheed Karim, Muthanna H. Al-Dahhan

Chemical and Biochemical Engineering Faculty Research & Creative Works

Manure Waste from Dairy Farms Has Been Used for Methane Production for Decades, However, Problems Such as Digester Failure Are Routine. the Problem Has Been Investigated in Small Scale (1-2 L) Digesters in the Laboratory; However, Very Little Scale-Up to Intermediate Scales Are Available. We Report Production of Methane in a 100-L Digester and the Results of an Investigation into the Effect of Partial Mixing Induced by Gas Upflow/recirculation in the Digester. the Digester Was Operated for a Period of About 70 D (With 16-D Hydraulic Retention Time) with and Without the Mixing Induced by Gas Recirculation through an Internal …

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An Investigation Into The Structure And Reactivity Of Calcium-Zinc-Silicate Ionomer Glasses Using Mas-Nmr Spectroscopy, D. Boyd, Mark R. Towler, R. V. Law, R. G. Hill May 2006

An Investigation Into The Structure And Reactivity Of Calcium-Zinc-Silicate Ionomer Glasses Using Mas-Nmr Spectroscopy, D. Boyd, Mark R. Towler, R. V. Law, R. G. Hill

Chemical and Biochemical Engineering Faculty Research & Creative Works

The suitability of Glass Polyalkenoate Cements (GPCs) for orthopaedic applications is retarded by the presence in the glass phase of aluminum, a neurotoxin. Unfortunately, the aluminum ion plays an integral role in the setting process of GPCs and its absence is likely to hinder cement formation. However, the authors have previously shown that aluminum-free GPCs may be formulated based on calcium zinc silicate glasses and these novel materials exhibit significant potential as hard tissue biomaterials. However, there is no data available on the structure of these glasses. 29Si MAS-NMR, differential thermal analysis (DTA), X-ray diffraction (XRD), and network crosslink density …

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Gas Holdup In Trayed Bubble Column Reactors, Javier Alvaré, Muthanna H. Al-Dahhan Apr 2006

Gas Holdup In Trayed Bubble Column Reactors, Javier Alvaré, Muthanna H. Al-Dahhan

Chemical and Biochemical Engineering Faculty Research & Creative Works

The Sectionalization of Conventional Bubble Columns by Perforated Trays into Trayed Bubble Columns (TBCs) Has Much Potential in Biochemical and Petroleum Refining Processes, as an Effective Way to Improve the Gas-Liquid Contacting Efficiency and Reduce the Liquid Back mixing. in This Work, the Effects of Tray Geometry, Superficial Gas Velocity, and Superficial Liquid Velocity on the overall Gas Holdup Have Been Investigated. It Was Determined that the Trays Significantly Increase the overall Gas Holdup. the Tray Hole Diameter and Superficial Gas Velocity Were Determined to Be the Most Important Factors. © 2006 American Chemical Society.

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Ultrasonically Set Glass Polyalkenoate Cements For Orthodontic Applications, D. A. Tanner, N. Rushe, Mark R. Towler Apr 2006

Ultrasonically Set Glass Polyalkenoate Cements For Orthodontic Applications, D. A. Tanner, N. Rushe, Mark R. Towler

Chemical and Biochemical Engineering Faculty Research & Creative Works

There is an accepted clinical requirement for a luting cement that can be command set upon satisfactory placement of an orthodontic appliance onto dentition. This work evaluates the suitability of ultrasound, imparted from a dental scaler, as a potential mechanism for achieving this. The net setting times and subsequent compressive strengths of a range of commercial and experimental glass polyalkenoate cements (GPCs) were evaluated, using modified ISO 9917 methods, when set both chemically and by ultrasound. The ultrasound was applied to the GPC through an orthodontic brace. It was possible to command set GPCs by the application of five to …

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Optimisation Of The Composition Of An Acrylic Bone Cement: Application To Relative Amounts Of The Initiator And The Activator/Co-Initiator In Surgical Simplex®P, S. Madigan, M. R. Towler, G. Lewis Apr 2006

Optimisation Of The Composition Of An Acrylic Bone Cement: Application To Relative Amounts Of The Initiator And The Activator/Co-Initiator In Surgical Simplex®P, S. Madigan, M. R. Towler, G. Lewis

Chemical and Biochemical Engineering Faculty Research & Creative Works

In cemented arthroplasties, the two-part self-curing acrylic bone cement is currently the only material used for anchoring the total joint replacement to the contiguous bone. In virtually all commercially available formulations of this cement, the agents used for the initiation and activation/co-initiation of the radical polymerisation reaction are benzoyl peroxide (BPO) and N, N dimethyl-paratoluidine (DMPT), respectively. There are no reports in the open literature on the rationale for the amounts of these and other constituents in the formulations of the cement. Given the concerns that have been raised in the literature regarding the effect of residual DMPT on the …

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Liquid Phase Mixing In Trayed Bubble Column Reactors, Javier Alvaré, Muthanna H. Al-Dahhan Mar 2006

Liquid Phase Mixing In Trayed Bubble Column Reactors, Javier Alvaré, Muthanna H. Al-Dahhan

Chemical and Biochemical Engineering Faculty Research & Creative Works

The Compartmentalization of Conventional Bubble Columns by Perforated Trays Constitutes a Very Effective Method to Reduce the Liquid Back mixing. the Effect of Tray Design and Operating Conditions on the overall Liquid Mixing Was Studied in a Bench-Scale Trayed Bubble Column. the Extent of Liquid Back mixing in the Column Was Investigated in Light of Liquid-Phase Tracer Response Experiments. in Average, a Three-Fold Reduction in the Liquid Back mixing Was Achieved in the Trayed Column as Compared to the Column Without the Trays. Moreover, the Tray Open Area and the Superficial Liquid Velocity Were Found to Have the Strongest Effects …

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Wagging The Contact Line: Transverse And Longitudinal Waves, S. Saritha, Partho Neogi Feb 2006

Wagging The Contact Line: Transverse And Longitudinal Waves, S. Saritha, Partho Neogi

Chemical and Biochemical Engineering Faculty Research & Creative Works

Kinetics of wetting has been explored where the contact line not only sees a steady spreading but also has longitudinal or transverse oscillations imposed on it. The latter case is realized when spreading takes place over a rough surface. The effects of the imposed motion are small, which seem to be due to low spreading rates and small dynamic contact angles used in this study. However, a singularity is seen in viscous dissipation during the movement on the model rough surface, which is interpreted here as an instability that is similar to Haines' jumps and stick-slip phenomena, with possible entrainment …

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Phase Distribution In An Upflow Monolith Reactor Using Computed Tomography, M. (Muthanna) H. Al-Dahhan, A. Kemoun, A. R. Cartolano Feb 2006

Phase Distribution In An Upflow Monolith Reactor Using Computed Tomography, M. (Muthanna) H. Al-Dahhan, A. Kemoun, A. R. Cartolano

Chemical and Biochemical Engineering Faculty Research & Creative Works

Computed Tomography (CT) is Known to Be a Viable Technique for Determining Flow Maldistribution in Two-Phase Flow through Packed Beds. in This Study, Gamma Ray Computed Tomography Has Been Used to Quantify the Flow Distribution in a Monolith Catalytic Bed, with Water as the Liquid Phase and Air as the Gas Phase, Flowing Co-Currently Upward. the Flow Conditions Were Selected to Bracket Some Commercially Viable Operating Conditions for Such Reactors. in the Monolith Core Region, Fairly Uniform Flow Distribution Has Been Obtained for All the Flow Conditions Used. This Distribution is Quantified using the Standard Deviation of the Holdup Distribution. …

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Supercritical-Carbon Dioxide-Assisted Cyclic Deposition Of Metal Oxide And Metal Thin Films, Dipak Barua, Theodosia Gougousi, Erin D. Young, Gregory N. Parsons Feb 2006

Supercritical-Carbon Dioxide-Assisted Cyclic Deposition Of Metal Oxide And Metal Thin Films, Dipak Barua, Theodosia Gougousi, Erin D. Young, Gregory N. Parsons

Chemical and Biochemical Engineering Faculty Research & Creative Works

Thin films of aluminum oxide and palladium were deposited on silicon at low temperatures (70-120 °C) by a cyclic adsorption/reaction processes using supercritical CO2 solvent. Precursors included Al(hfac)3, Al(acac)3, and Pd(hfac)2, and aqueous H2O2, tert-butyl peracetate, and H2 were used as the oxidants or reductants. For the precursors studied, growth proceeds through a multilayer precursor adsorption in each deposition cycle, and film thickness increased linearly with the number of growth cycles.

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Surface Modification Of Su-8 By Photografting Of Functional Polymers For Lab-On-A-Chip Applications, Zhan Gao, David Henthorn, Chang-Soo Kim Jan 2006

Surface Modification Of Su-8 By Photografting Of Functional Polymers For Lab-On-A-Chip Applications, Zhan Gao, David Henthorn, Chang-Soo Kim

Chemical and Biochemical Engineering Faculty Research & Creative Works

Due to the high flexibility and versatility in the process development of microfluidic devices, an epoxybased, high-aspect ratio photoresist SU-8 is now attracting attention as the main structuring material of the fluidic channels. Manipulation of the surface properties of SU-8 channel wall is critical to attach functional films such as enzyme-immobilized layers or biocompatible layers. We describe a new in situ patterning method to form a hydrogel film on SU-8 by a photografted polymerization procedure. The hydrophobic surface of SU-8 is modified using a surface bound initiator HCPK (1-hydroxycyclohexyl phenyl ketone). A p-HEMA (poly-2-hydroxyethylmethacrylate) hydrogel film is grafted by photopolymerization …

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Experimental Study Of The Solids Velocity Field In Gas-Solid Risers, Satish Bhusarapu, Muthanna H. Al-Dahhan, Milorad P. Duduković, Steven Trujillo, Timothy J. O'Hern Dec 2005

Experimental Study Of The Solids Velocity Field In Gas-Solid Risers, Satish Bhusarapu, Muthanna H. Al-Dahhan, Milorad P. Duduković, Steven Trujillo, Timothy J. O'Hern

Chemical and Biochemical Engineering Faculty Research & Creative Works

Solids Flow Dynamics in Gas-Solid Risers is Inherently Complex. Model Refinement through Experimental Validation Requires the Acquisition of Detailed Nonintrusive Measurements. in This Study, Noninvasive Computer-Automated Radioactive Particle Tracking (CARPT) is Employed to Visualize and Quantify in a Three-Dimensional Domain the Solids Dynamics and Mixing in Gas-Solid Risers. This Technique Has the Added Advantage that, along with the Derived Eulerian Solids Flow Field (Time-Average Velocity Map and Various Turbulence Parameters Such as the Reynolds Stresses, Turbulent Kinetic Energy), It Also Provides Directly the Lagrangian Description of the Solids Motion. the Solids Velocity Field Data Are Obtained in Two Different Risers …

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Solids Flow Mapping In A High Pressure Slurry Bubble Column, Novica Rados, Ashfaq Shaikh, Muthanna H. Al-Dahhan Nov 2005

Solids Flow Mapping In A High Pressure Slurry Bubble Column, Novica Rados, Ashfaq Shaikh, Muthanna H. Al-Dahhan

Chemical and Biochemical Engineering Faculty Research & Creative Works

Successful Design and Scale-Up of Slurry Bubble Column Reactors (SBCRs) Require Proper Understanding of How Operating Conditions Affect their Flow Behavior. Presently, there is Little Information on the Flow Dynamics of Solids (E.g., Distribution of Velocities and Turbulent Parameters) in Slurry Systems that Are Operated at Industrially Relevant Conditions of High Pressure, High Superficial Gas Velocities, and High Solids Loading. Computer Automated Radio Particle Tracking (CARPT) is Widely Recognized as One of a Few Techniques that Can Be Reliably Used Even in Highly Turbulent and Opaque Slurry Flows. This Work Utilizes an Improved CARPT Technique to Investigate the Effect of …

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Polymer-Mediated Synthesis Of Highly Dispersed Pt Nanoparticles On Carbon Black, Min Chen, Yangchuan Xing Sep 2005

Polymer-Mediated Synthesis Of Highly Dispersed Pt Nanoparticles On Carbon Black, Min Chen, Yangchuan Xing

Chemical and Biochemical Engineering Faculty Research & Creative Works

A new method was developed to prepare highly dispersed Pt nanoparticles on carbon black to use as proton exchange membrane (PEM) fuel cell catalysts. This method involves using a polymer, poly-(vinylpyrrolidone) (PVP), to prevent particle aggregation and thereby reduce nanoparticle sizes to achieve high dispersion. It was found that Pt nanoparticles mediated by PVP are smaller than those obtained without PVP and have a narrower size distribution. Well-dispersed Pt nanoparticles with metal loadings from 5 to 35 wt % were obtained on carbon black (Vulcan XC-72R). It was found that well-dispersed Pt nanoparticles on carbon black could be synthesized at …

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The Processing, Mechanical Properties And Bioactivity Of Zinc Based Glass Ionomer Cements, D. Boyd, Mark R. Towler Sep 2005

The Processing, Mechanical Properties And Bioactivity Of Zinc Based Glass Ionomer Cements, D. Boyd, Mark R. Towler

Chemical and Biochemical Engineering Faculty Research & Creative Works

The suitability of Glass Ionomer Cements (GICs) for use in orthopaedics is retarded by the presence in the glass phase of aluminium, a neurotoxin. Unfortunately, the aluminium ion plays an integral role in the setting process of a GIC and its absence is likely to hinder cement formation. However, zinc oxide, a bacteriocide, can act both as a network modifying oxide and an intermediate oxide in a similar fashion to alumina and so ternary systems based on zinc silicates often have extensive regions of glass formation. The purpose of this research was to produce novel GICs based on calcium zinc …

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Exfoliated Graphite Nanofibers For Hydrogen Storage, Angela D. Lueking, Ling Pan, Deepa L. Narayanan, Caroline E. Burgess Clifford Sep 2005

Exfoliated Graphite Nanofibers For Hydrogen Storage, Angela D. Lueking, Ling Pan, Deepa L. Narayanan, Caroline E. Burgess Clifford

Chemical and Biochemical Engineering Faculty Research & Creative Works

Exfoliation of graphite nanofibers (GNF) expands the interplanar spacing of the GNF, which leads to increased hydrogen storage. Hydrogen uptake measurements at 20 bar indicated that the overall hydrogen uptake and operative adsorption temperature are sensitive to the structural variations and graphitic spacing. The increased surface area of the EGNF-1000 led to a 1.2% hydrogen uptake at 77 K and 20 bar, a three-fold increase in hydrogen physisorption of the starting material. These results suggested that selective exfoliation of a nanofiber is a means by which to control the relative binding energy of the hydrogen interaction with the carbon structure …

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Modeling Catalytic Trickle-Bed And Upflow Packed-Bed Reactors For Wet Air Oxidation Of Phenol With Phase Change, Jing Guo, Muthanna H. Al-Dahhan Aug 2005

Modeling Catalytic Trickle-Bed And Upflow Packed-Bed Reactors For Wet Air Oxidation Of Phenol With Phase Change, Jing Guo, Muthanna H. Al-Dahhan

Chemical and Biochemical Engineering Faculty Research & Creative Works

In This Study, to Simulate the Steady-State Behavior of Packed-Bed Reactors for Catalytic Wet Oxidation of Phenol, One-Dimensional (1D) Axial Dispersion Model for the Liquid Phase is Coupled with a Cell Stack Model for the Gas Phase, Providing Considerable Phase Change under the Selected Operating Conditions. the Reactor Scale Governing Equations, Reaction Kinetics Involved, and Solution Strategy Are Discussed. the Computational Approach Accounts for the Observed Catalyst Activities, Combined with Local Transport and Catalyst Wetting Effects. the Approach Selected is Shown to Be Suitable and Efficient in Dealing with the Problem in Question. Comparisons of Simulated Model Predictions and Lab …

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Flow Distribution Characteristics Of A Gas-Liquid Monolith Reactor, Shaibal Roy, Muthanna H. Al-Dahhan Aug 2005

Flow Distribution Characteristics Of A Gas-Liquid Monolith Reactor, Shaibal Roy, Muthanna H. Al-Dahhan

Chemical and Biochemical Engineering Faculty Research & Creative Works

Flow Distribution Characteristics in a 0.05 M Diameter Monolith Reactor, Operated Co-Current Downward in the Taylor Flow Regime, Was Investigated and Quantified using Gamma Ray Computed Tomography (CT). the Results Indicate that the Flow Distribution is a Strong Function of Liquid Distributor Design, and Gas and Liquid Superficial Velocities. Additionally, within the Range of Gas and Liquid Superficial Velocities Investigated, a Window of Operating Condition (Gas and Liquid Velocities) Was Identified Which Resulted in a Close to Uniform Phase Distribution. © 2005 Elsevier B.V. All Rights Reserved.

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Dynamic Modeling Of Slurry Bubble Column Reactors, Novica Rados, Muthanna H. Al-Dahhan, Milorad P. Duduković Aug 2005

Dynamic Modeling Of Slurry Bubble Column Reactors, Novica Rados, Muthanna H. Al-Dahhan, Milorad P. Duduković

Chemical and Biochemical Engineering Faculty Research & Creative Works

The Multicomponent, One-Dimensional, and Compartment-Based Dynamic Model Developed by Rados Et Al. (Catal. Today 2003, 79-80, 211-218) Has Been Used to Study the Performance of Slurry Bubble Columns Operated with Two Chemical Reaction Systems. One Reaction Causes Contraction in the Gas-Phase Volume, and the Other Causes Expansion. the Change in the Gas Flow Rate (Expansion or Contraction) Along the Reactor as a Result of the Chemical Reaction Kinetics is Accounted for by the overall Mass Balance of the Gas Phase Represented by Large and Small Bubbles. the Importance of Properly Accounting for the Change in the Gas Flow Rate Has …

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Multicomponent Flow-Transport-Reaction Modeling Of Trickle Bed Reactors: Application To Unsteady State Liquid Flow Modulation, M. R. Khadilkar, M. (Muthanna) H. Al-Dahhan, M. P. Duduković Aug 2005

Multicomponent Flow-Transport-Reaction Modeling Of Trickle Bed Reactors: Application To Unsteady State Liquid Flow Modulation, M. R. Khadilkar, M. (Muthanna) H. Al-Dahhan, M. P. Duduković

Chemical and Biochemical Engineering Faculty Research & Creative Works

A One-Dimensional Reactor and Catalyst Pellet Scale Flow-Transport-Reaction Model Utilizing the Multicomponent Stefan-Maxwell Formulation for Inter- and Intraphase Transport is Developed to Simulate Unsteady State Operation in Trickle Bed Reactors. the Governing Equations and Method of Solution Are Discussed. Results Are Presented for a Model Reaction System (Hydrogenation of A-Methylstyrene) under Gas Reactant Limiting Conditions, for Liquid Flow Modulation as a Test Case of Unsteady State Operation. Model Simulations Predict that Periodic Liquid Flow Modulation Can Alter the Supply of Liquid and Gaseous Reactants to the Catalyst and Result in Reactor Performance Enhancement above that Achieved in Steady State Operation. …

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Multiphase Flow Packed-Bed Reactor Modeling: Combining Cfd And Cell Network Model, Yi Jiang, Jing Guo, Muthanna H. Al-Dahhan Jul 2005

Multiphase Flow Packed-Bed Reactor Modeling: Combining Cfd And Cell Network Model, Yi Jiang, Jing Guo, Muthanna H. Al-Dahhan

Chemical and Biochemical Engineering Faculty Research & Creative Works

The Performance of a Multiphase Flow Packed-Bed Reactor Was Evaluated by a Mixing-Cell Network Model in Which the Cell-Scale Flow Field Information Was Provided by Multifluid CFD Modeling. Such a Sequentially Combined Modeling Approach Was Able to Show the Heterogeneity of Liquid Species Conversion in a Trickle-Bed Reactor that Has Been Confirmed by in Situ Magnetic Resonance Experiments. 1 a Conventional Plug Flow Model (PFM) and Axial Dispersion Model (ADM) Showed Either overpredicted or Underpredicted Conversion Compared with the Conversion Computed from the CFD-Cell Network Model. Preliminary Case Study Has Shown the Ability of the CFD-Cell Network Model in Assessing …

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Modeling And Scale-Up Of Mixing- And Temperature-Sensitive Chemical Reactions, Gary Patterson Jul 2005

Modeling And Scale-Up Of Mixing- And Temperature-Sensitive Chemical Reactions, Gary Patterson

Chemical and Biochemical Engineering Faculty Research & Creative Works

A review of published measurements of yield for complex chemical reactions in mixed reactors of various types and methods of modeling and simulating such reactions for the purpose of reactor scale-up shows the extent of progress that has been made. Reaction kinetics for very fast competitive reactions are usually difficult and expensive to determine. Many reaction processes must be scaled up from bench- and/or pilot-scale experiments that produce yield data under various mixing conditions. the variables that strongly affect the yield results are the reaction types and their rates, feed point in the reactor, feed injection velocity and scale, mixing …

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Liquid Saturation And Gas-Liquid Distribution In Multiphase Monolithic Reactors, Tobias Bauer, Shaibal Roy, Ruediger Lange, Muthanna H. Al-Dahhan Jun 2005

Liquid Saturation And Gas-Liquid Distribution In Multiphase Monolithic Reactors, Tobias Bauer, Shaibal Roy, Ruediger Lange, Muthanna H. Al-Dahhan

Chemical and Biochemical Engineering Faculty Research & Creative Works

The Monolith Bed is One of the Promising Catalytic Reactors for a Number of Chemical Gas-Liquid-Solid Processes. in the Present Work, Liquid Saturations for Five Different Monoliths Have Been Investigated Experimentally in a Cold-Flow Unit with a Reactor Diameter of 5.0 Cm. the Influences of Gas and Liquid Flow Rates and of the Direction of Two-Phase Flow on Liquid Saturation Were Examined. the Results Indicate that the Direction of Flow Has No Significant Influence on Liquid Saturation for Proper Gas-Liquid Distribution. the Experimental Results Are in Good Agreement with Predictions of the Drift Flux Model using the Distribution Parameter Proposed …

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