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Chemical and Biochemical Engineering Faculty Research & Creative Works

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Full-Text Articles in Biochemical and Biomolecular Engineering

Prediction Of Axial Liquid Velocity Profile In Bubble Columns, Yuanxin Wu, M. (Muthanna) H. Al-Dahhan Feb 2001

Prediction Of Axial Liquid Velocity Profile In Bubble Columns, Yuanxin Wu, M. (Muthanna) H. Al-Dahhan

Chemical and Biochemical Engineering Faculty Research & Creative Works

The Liquid Flow and Mixing Behavior in Bubble Columns is Partially Described by Means of Global Liquid Recirculation Velocity Profile. Due to the Complex Character of the Flow in Bubble Columns, the Prediction of the Axial Liquid Circulation is Still a Difficult Task. in This Work, the Following Correlation is Proposed for the Liquid Recirculation Profile: VLO/ VL(R)= 1 - 2.65 * N0.44 * C[R/r] 2.65, N0.442,c , Where N and C Are the Gas Radial Holdup Profile Parameters Evaluated by the Correlations Proposed by Wu, Ong and Al-Dahhan (Chemical Engineering Science, 56 (2001) 1207-1210). N = 2.188 X 103 …

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Predictions Of Radial Gas Holdup Profiles In Bubble Column Reactors, Yuanxin Wu, Boon Cheng Ong, M. (Muthanna) H. Al-Dahhan Feb 2001

Predictions Of Radial Gas Holdup Profiles In Bubble Column Reactors, Yuanxin Wu, Boon Cheng Ong, M. (Muthanna) H. Al-Dahhan

Chemical and Biochemical Engineering Faculty Research & Creative Works

Gas Holdup and its Profile Are Important Parameters to Be Characterized in Bubble Column Reactors. Proper Prediction of the Radial Gas Holdup Profiles is Necessary for Determining Liquid Mixing, Flow Regime Transition, Heat and Mass Transfer. in This Study, the Following Gas Holdup Profile Form, Which Can Be Fitted to the Observed Holdup Profiles, is Proposed: EG = EG (N + 2/n + 2 - 2c) [1 - C(R/R)n]. the Parameters N and C Needed to Describe the Gas Holdup Profile Are Correlated with Appropriate Dimensionless Groups. N = 2.188 X 103 ReG-0.598 Frg0.146 MoL-0.004, C = 4.32 X 10-2 …

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Comparison Of Single- And Two-Bubble Class Gas-Liquid Recirculation Models - Application To Pilot-Plant Radioactive Tracer Studies During Methanol Synthesis, Puneet Gupta, Muthanna H. Al-Dahhan, Milorad P. Dudukovic, Bernard A. Toseland Feb 2001

Comparison Of Single- And Two-Bubble Class Gas-Liquid Recirculation Models - Application To Pilot-Plant Radioactive Tracer Studies During Methanol Synthesis, Puneet Gupta, Muthanna H. Al-Dahhan, Milorad P. Dudukovic, Bernard A. Toseland

Chemical and Biochemical Engineering Faculty Research & Creative Works

Radioactive Gas Tracer Measurements Conducted during Liquid-Phase Methanol Synthesis from Syngas in a Pilot-Scale Slurry Bubble Column at the Alternate Fuels Development Unit (AFDU), La Porte Have Been Compared with Simulations from Two Mechanistic Reactor Models - Single-Bubble Class Model (SBCM) and Two-Bubble Class Model (TBCM). the Model Parameters Are Estimated from an Independent Sub-Model Gas and Liquid Recirculation, and the Long-Time-Averaged Slip Velocity between the Gas and Liquid/slurry in the Column Center Can Be as High as 50-60 Cm/s Depending on the Operating Conditions. Comparison of Experimental Data with Simulation Results from the Two Models Indicates that Accurate Description …

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Hydrodynamics Of Churn Turbulent Bubble Columns: Gas-Liquid Recirculation And Mechanistic Modeling, Puneet Gupta, Booncheng Ong, Muthanna H. Al-Dahhan, Milorad P. Dudukovic, Bernard A. Toseland Jan 2001

Hydrodynamics Of Churn Turbulent Bubble Columns: Gas-Liquid Recirculation And Mechanistic Modeling, Puneet Gupta, Booncheng Ong, Muthanna H. Al-Dahhan, Milorad P. Dudukovic, Bernard A. Toseland

Chemical and Biochemical Engineering Faculty Research & Creative Works

A Phenomenological (Mechanistic) Model Has Been Developed for Describing the Gas and Liquid/slurry Phase Mixing in Churn Turbulent Bubble Columns. the Gas and Liquid Phase Recirculation Rates in the Reactor, Which Are Needed as Inputs to the Mechanistic Reactor Model Are Estimated Via a Sub-Model Which Uses the Two-Fluid Approach in Solving the Navier-Stokes Equations. This Sub-Model Estimates the Effective Bubble Diameter in the Reactor Cross-Section and Provides a Consistent Basis for the Estimation of the Volumetric Mass Transfer Coefficients. the Strategy for the Numerical Solution of the Sub-Model Equations is Presented Along with the Simulation Results for a Few …

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Purification And Characterization Of Crystallins By Aqueous Two-Phase Extraction, Ondrea Bermudez, Daniel Forciniti Jan 2001

Purification And Characterization Of Crystallins By Aqueous Two-Phase Extraction, Ondrea Bermudez, Daniel Forciniti

Chemical and Biochemical Engineering Faculty Research & Creative Works

Crystallins are a family of water-soluble proteins that constitute up to 90% of the water-soluble proteins in mammalian eye lenses. We present in this paper an alternative purification method for these proteins using polyethylene glycol/dextran aqueous two-phase extraction. Under the appropriate conditions, we were able to recover the γ-crystallin fraction essentially free of the remaining proteins. High concentrations of salt at a neutral pH maximize the recovery of γ-crystallins in the top phase and minimize the contamination by the other proteins present in the lenses. The proposed protocol decreases the separation time by about 50%. The complex partition behavior observed …

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Novel Processing Of Hydroxyapatite-Zirconia Composites Using Nano-Sized Particles, Mark R. Towler, I. R. Gibson, S. M. Best Dec 2000

Novel Processing Of Hydroxyapatite-Zirconia Composites Using Nano-Sized Particles, Mark R. Towler, I. R. Gibson, S. M. Best

Chemical and Biochemical Engineering Faculty Research & Creative Works

A method to produce composites of hydroxyapatite (HA) with ZrO2 (Y-TZP) additions between 0 and 10 wt % at a low sinter temperature of 750 °C is presented. The method limits the amount of reaction between the HA and ZrO2. A ZrO2 loading level that would improve strength while limiting the decomposition of the HA is studied.

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Film Mass Transfer Coefficient Expressions For Electroosmotic Flows, Athanasios I. Liapis, Brian A. Grimes Sep 2000

Film Mass Transfer Coefficient Expressions For Electroosmotic Flows, Athanasios I. Liapis, Brian A. Grimes

Chemical and Biochemical Engineering Faculty Research & Creative Works

Expressions are developed and presented that could be used to determine the film mass transfer coefficient of a solute in electroosmotic flows. In contrast to pressure-driven flows at low Reynolds numbers where the film mass transfer coefficient is independent of the linear characteristic dimension of the channel for flow, in electroosmotically driven flows at low Reynolds numbers the film mass transfer coefficient is shown to be a function of the ratio R/λ, where R is the channel radius and λ is the Debye length. This result implies that for electroosmotically driven flows in a packed bed or porous monolith with …

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Determination Of The Intraparticle Electroosmotic Volumetric Flow-Rate, Velocity And Peclet Number In Capillary Electrochromatography From Pore Network Theory, B. A. Grimes, J. J. Meyers, Athanasios I. Liapis Aug 2000

Determination Of The Intraparticle Electroosmotic Volumetric Flow-Rate, Velocity And Peclet Number In Capillary Electrochromatography From Pore Network Theory, B. A. Grimes, J. J. Meyers, Athanasios I. Liapis

Chemical and Biochemical Engineering Faculty Research & Creative Works

The results obtained from the pore network model employed in this work, clearly show that the magnitudes of the intraparticle electroosmotic volumetric flowrate, Q(intrap), and velocity, < v (intrap,x) >, in the pores of the charged porous silica particles considered in this study are greater than zero. The intraparticle Peclet number, Pe(intra), of a solute in these charged porous silica particles would be greater than zero, and, in fact, the magnitude of the intraparticle Peclet number, Pe(intrap), of lysozyme is greater than unity for all the values of the pore connectivity, n(T), of the intraparticle pores and of the applied electric potential difference …

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Information Models For Planning And Scheduling Of Chemical Processes, Neil L. Book, Vivek Bhatnagar Jul 2000

Information Models For Planning And Scheduling Of Chemical Processes, Neil L. Book, Vivek Bhatnagar

Chemical and Biochemical Engineering Faculty Research & Creative Works

The Process Data Exchange Institute (pdXi) has developed an information model for process engineering data. The pdxi information model is designed to facilitate the storage and exchange of steady-state process engineering data. Batch and real-time operating data can be stored and exchanged using the pdXi model as snapshots (data that characterizes the process at a specific point in time). Snapshots are an inefficient method for storing and exchanging batch and real-time data. Also, snapshots do not contain data that describe the processes that occur between snapshots. Sharma and Book modified the basic structure of the pdXi information model to make …

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Inherently Safer Analysis Of The Attainable Region Process For The Adiabatic Oxidation Of Sulfur Dioxide, Neil L. Book, Venkata U.B. Challagulla Jul 2000

Inherently Safer Analysis Of The Attainable Region Process For The Adiabatic Oxidation Of Sulfur Dioxide, Neil L. Book, Venkata U.B. Challagulla

Chemical and Biochemical Engineering Faculty Research & Creative Works

The attainable region (AR) method is used to obtain the optimal design and operating conditions for the adiabatic oxidation of sulfur dioxide to sulfur trioxide. The optimum process layout for this exothermic, catalytic, reversible reaction is a complex interconnection of reactors that achieves a conversion in excess of the equilibrium value for a single adiabatic reactor. The complex design obtained from the AR method is technically and economically superior to a single adiabatic reactor, but it is inferior from a safety perspective as a result of its complex interconnections and its high preheat temperature. The strategies of inherently safer design …

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Single Phase Flow Modeling In Packed Beds: Discrete Cell Approach Revisited, Y. Jiang, M. R. Khadilkar, M. (Muthanna) H. Al-Dahhan, M. P. Dudukovic May 2000

Single Phase Flow Modeling In Packed Beds: Discrete Cell Approach Revisited, Y. Jiang, M. R. Khadilkar, M. (Muthanna) H. Al-Dahhan, M. P. Dudukovic

Chemical and Biochemical Engineering Faculty Research & Creative Works

A Discrete Cell Model (DCM), based on the Minimization of the Total Rate of Energy Dissipation, is Applied to Compute the Fluid Velocity Field in Two-Dimensional Packed Beds. the Analysis of the Individual Terms of the Energy Dissipation Rate Equation is Also Presented. the Results Obtained by DCM Are Validated Both by Comparing Them with the Solutions of Ensemble-Averaged Momentum and Mass Conservation Equations (CFDLIB Code) and by Available Experimental Results. the Differences between DCM and CFD Simulations Were Found to Be Confined to within a 10% Band over a Wide Range of Reynolds Numbers (Re' = 5-171). Thus, a …

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Reactor And Method For Solid Phase Peptide Synthesis, Nicholas Stepanluk, Keith Tomazi, Michael C. Stapleton Feb 2000

Reactor And Method For Solid Phase Peptide Synthesis, Nicholas Stepanluk, Keith Tomazi, Michael C. Stapleton

Chemical and Biochemical Engineering Faculty Research & Creative Works

A solid phase peptide synthesis reactor system and method of operating the reactor are provided. The reactor system includes a basket rotatable about an axis within a housing and a receiver which delivers fluid to; and collects fluid from; the housing. The basket has a perforate side wall against which a resin cake for the peptide synthesis formed. The reactor and receiver form a loop or circuit through which solutions are circulated. The circulation of the solutions prevents the reactor from flooding so that the basket Will not be submerged in solution and allows for the use of less liquid. …

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Effects Of Adding Sodium And Fluoride Ions To Glass Ionomer On Its Interactions With Sodium Fluoride Solution, R. W. Billington, P. C. Hadley, Mark R. Towler, G. J. Pearson, J. A. Williams Feb 2000

Effects Of Adding Sodium And Fluoride Ions To Glass Ionomer On Its Interactions With Sodium Fluoride Solution, R. W. Billington, P. C. Hadley, Mark R. Towler, G. J. Pearson, J. A. Williams

Chemical and Biochemical Engineering Faculty Research & Creative Works

This investigates the effects of the addition of Na and F ions to a glass ionomer cement in which those ions are not inherently present on its interactions with dilute (0.2%) NaF solution. Both the effect of the solution on the cement's surface morphology and the effect of the cement on the solution in terms of take up of Na+ and F- and of change in pH are to be investigated. These results are to be compared to previous results obtained with glasses which contained both, one, or neither of the ions as components of their glasses. NaF …

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The Influence Of Poly(Acrylic Acid) Molar Mass On The Properties Of Polyalkenoate Cements Formed From Zinc Oxide/Apatite Mixtures, Sinead Kenny, Robert G. Hill, Mark R. Towler Jan 2000

The Influence Of Poly(Acrylic Acid) Molar Mass On The Properties Of Polyalkenoate Cements Formed From Zinc Oxide/Apatite Mixtures, Sinead Kenny, Robert G. Hill, Mark R. Towler

Chemical and Biochemical Engineering Faculty Research & Creative Works

The influence of poly (acrylic acid) molar mass was investigated on cements formed from zinc oxide-apatite mixtures at three aging times: one, seven and 28 days. Cements based on both hydroxyapatite and fluorapatite were investigated. The compressive strength, un-notched fracture strength and fracture toughness increased markedly with poly (acrylic acid) molar mass. The fracture toughness and un-notched fracture strength increased with aging time for the two highest molar mass cements but decreased with time for the two lowest molar mass cements. The greater chain entanglement density present in the higher molar mass cements is thought to contribute significantly to the …

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Discriminating Trickle-Flow Hydrodynamic Models: Some Recommendations, F. Larachi, I. Iliuta, M. (Muthanna) H. Al-Dahhan, M. P. Dudukovic Jan 2000

Discriminating Trickle-Flow Hydrodynamic Models: Some Recommendations, F. Larachi, I. Iliuta, M. (Muthanna) H. Al-Dahhan, M. P. Dudukovic

Chemical and Biochemical Engineering Faculty Research & Creative Works

The Forecasting Ability of Five One-Dimensional (1-D) Two-Fluid Phenomenological Models for Liquid Holdup and Two-Phase Pressure Drop in Trickle-Flow Reactors Was Evaluated using the Most Comprehensive Trickle-Flow Regime Database. All of These Models, Namely, the Permeability Model, the Slit Model, the Extended Slit Model, the 1-D CFD Model, and the Double-Slit Model Can Be Used to Predict Liquid Holdup. among Them, the Permeability and the Slit Models, Because of a Much Simpler Structure, Are Recommended. the Extended Slit Model based on Iliuta Et Al. (Ind. Eng. Chem. Res. 1998, 37, 4542) Shear and Slip Constitutive Relationships Can Be Employed for …

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Effects Of Cosolvents And Ph On Protein Adsorption On Polystyrene Latex: A Dynamic Light Scattering Study, Da Song, Daniel Forciniti Jan 2000

Effects Of Cosolvents And Ph On Protein Adsorption On Polystyrene Latex: A Dynamic Light Scattering Study, Da Song, Daniel Forciniti

Chemical and Biochemical Engineering Faculty Research & Creative Works

Dynamic light scattering was used to study the adsorption of two proteins with different surface properties (IgG and HSA) on negatively charged polystyrene latex. The proteins were adsorbed from water and from water/methanol and water/glycerol mixtures at various pH. Some striking differences between the adsorption behaviors of the proteins were observed. Whereas the thickness of the adsorbed layer of HSA was extremely sensitive to pH and solvent composition, that of IgG was not. IgG mainly showed an end-on orientation on polystyrene whereas several different surface orientations are suggested for HSA under different conditions. The addition of methanol inhibited the adsorption …

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Drawbacks Of The Dissolution Method For Measurement Of The Liquid-Solid Mass-Transfer Coefficients In Two-Phase Flow Packed-Bed Reactors Operated At Low And High Pressures, Muthanna H. Al-Dahhan, Wes Highfill, Boon Tee Ong Jan 2000

Drawbacks Of The Dissolution Method For Measurement Of The Liquid-Solid Mass-Transfer Coefficients In Two-Phase Flow Packed-Bed Reactors Operated At Low And High Pressures, Muthanna H. Al-Dahhan, Wes Highfill, Boon Tee Ong

Chemical and Biochemical Engineering Faculty Research & Creative Works

The Dissolution Method Was Used Predominantly at Atmospheric Conditions to Measure the Liquid-Solid Mass-Transfer Coefficient in Two-Phase Flow Packed-Bed Reactors. in an Attempt to Investigate the Effect of Reactor Pressure and Gas Flow Rate on the Liquid-Solid Mass-Transfer Coefficient in a Trickle-Bed Reactor using the Dissolution Method, Difficulties Were Encountered in Implementing This Method at Low- to High-Pressure Operation. Noticeable Losses in the Dissolved Material Were Observed as a Result of Flashing/stripping from the Liquid Phase to the Atmosphere and the Effluent Gas Stream. This Leads to Misinterpretation of the Effect of Reactor Pressure and to Improper Conclusions. in This …

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Double-Slit Model For Partially Wetted Trickle Flow Hydrodynamics, I. Iliuta, F. Larachi, M. (Muthanna) H. Al-Dahhan Jan 2000

Double-Slit Model For Partially Wetted Trickle Flow Hydrodynamics, I. Iliuta, F. Larachi, M. (Muthanna) H. Al-Dahhan

Chemical and Biochemical Engineering Faculty Research & Creative Works

A Double-Slit Model Developed Can Predict the Frictional Two-Phase Pressure Drop, External Liquid Holdup, Pellet-Scale External Wetting Efficiency, and Gas - Liquid Interfacial Area in Cocurrent Downflow Trickle-Bed Reactors Operated under Partially Wetted Conditions in the Trickle Flow Regime. the Model, an Extension of the Holub Et Al. (1992, 1993) Mechanistic Pore-Scale Phenomenological Approach, Was Designed to Mimic the Actual Bed Void by Two Inclined and Interconnected Slits: Wet and Dry Slit. the External Wetting Efficiency is Linked to Both the Pressure Drop and External Liquid Holdup. the Model Also Predicts Gas - Liquid Interfacial Areas in Partially Wetted Conditions. …

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Modeling And Simulation Of The Dynamic Behavior Of Monoliths: Effects Of Pore Structure From Pore Network Model Analysis And Comparison With Columns Packed With Porous Spherical Particles, Athanasios I. Liapis, J. J. Meyers, Orrin K. Crosser Dec 1999

Modeling And Simulation Of The Dynamic Behavior Of Monoliths: Effects Of Pore Structure From Pore Network Model Analysis And Comparison With Columns Packed With Porous Spherical Particles, Athanasios I. Liapis, J. J. Meyers, Orrin K. Crosser

Chemical and Biochemical Engineering Faculty Research & Creative Works

A mathematical model is presented that could be used to describe the dynamic behavior, scale-up, and design of monoliths involving the adsorption of a solute of interest. The value of the pore diffusivity of the solute in the pores of the skeletons of the monolith is determined in an a priori manner by employing the pore network modeling theory of Meyers and Liapis [J. Chromatogr. A, 827 (1998) 197 and 852 (1999) 3]. The results clearly show that the pore diffusion coefficient, D(mp), of the solute depends on both the pore size distribution and the pore connectivity, n(T), of the …

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Network Modeling Of The Convective Flow And Diffusion Of Molecules Adsorbing In Monoliths And In Porous Particles Packed In A Chromatographic Column, J. J. Meyers, Athanasios I. Liapis Aug 1999

Network Modeling Of The Convective Flow And Diffusion Of Molecules Adsorbing In Monoliths And In Porous Particles Packed In A Chromatographic Column, J. J. Meyers, Athanasios I. Liapis

Chemical and Biochemical Engineering Faculty Research & Creative Works

A cubic lattice network of interconnected pores was constructed to represent the porous structure existing in a monolith (continuous bed) or in a column packed with porous chromatographic particles. Expressions were also constructed and utilized to simulate, through the use of the pore network model, the intraparticle interstitial velocity and pore diffusivity of adsorbate molecules in porous chromatographic particles or in monoliths under retained and unretained conditions. The combined effects of steric hindrance at the entrance to the pores and frictional resistance within the pores, as well as the effects of pore size, pore connectivity, n(T), of the porous network, …

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Fluid Dynamic Parameters In Bubble Columns With Internals, Jinwen Chen, Fan Li, Sujatha Degaleesan, Puneet Gupta, Muthanna H. Al-Dahhan, Milorad P. Duduković, Bernard A. Toseland Jul 1999

Fluid Dynamic Parameters In Bubble Columns With Internals, Jinwen Chen, Fan Li, Sujatha Degaleesan, Puneet Gupta, Muthanna H. Al-Dahhan, Milorad P. Duduković, Bernard A. Toseland

Chemical and Biochemical Engineering Faculty Research & Creative Works

The Knowledge of Gas Holdup, Liquid Recirculation and Turbulent Parameters is Important for Design and Performance Calculation of Bubble Column Reactors. Although Numerous Experimental Studies Have Been Reported on This Subject, Most Are Point Measurements Limited to Columns Without Internals Operated at Low Gas Velocities. in This Study, We Present the Results Obtained for the Gas Holdup Profiles, Time-Averaged Liquid Velocity Profiles, Turbulent Stresses and Eddy Diffusivities (Radial and Axial) Obtained in a 18″ (44 Cm) Diameter Column Without and with Internals Similar to Those Used in Industrial Scale Units (E.g., Heat Exchanger Tubes) using Both Air/water and Air/drakeoil 10 …

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Two-Phase Flow Distribution In 2d Trickle-Bed Reactors, Y. Jiang, M. R. Khadilkar, M. (Muthanna) H. Al-Dahhan, M. P. Dudukovic Jul 1999

Two-Phase Flow Distribution In 2d Trickle-Bed Reactors, Y. Jiang, M. R. Khadilkar, M. (Muthanna) H. Al-Dahhan, M. P. Dudukovic

Chemical and Biochemical Engineering Faculty Research & Creative Works

An Extended Discrete Cell Model (DCM), based on Minimization of Energy Dissipation Rate, is Applied to Predict Two-Phase Flow Distribution in the Two-Dimensional Trickle-Bed Reactors. the Main Advantages of DCM Are that It Can Qualitatively Capture the Experimental Observations, and Readily Distinguish between Flow Distribution in Prewetted and Non-Prewetted Beds, as Well as Reflect the Effects of Bed Structure and Inlet Liquid Distributor on Two Phase Flow Distribution. for Comparison Purpose, the Results of Liquid Distribution Obtained by DCM Are Compared with Both Computational Fluid Dynamics (CFD) Simulations and Experimental Observations in a 2D Bed. the Achieved Qualitative and Quantitative …

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Comparative Hydrodynamics Study In A Bubble Column Using Computer-Automated Radioactive Particle Tracking (Carpt)/Computed Tomography (Ct) And Particle Image Velocimetry (Piv), Jinwen Chen, Abdenour Kemoun, Muthanna H. Al-Dahhan, Milorad P. Duduković, D. J. Lee, Liang Shih Fan Jul 1999

Comparative Hydrodynamics Study In A Bubble Column Using Computer-Automated Radioactive Particle Tracking (Carpt)/Computed Tomography (Ct) And Particle Image Velocimetry (Piv), Jinwen Chen, Abdenour Kemoun, Muthanna H. Al-Dahhan, Milorad P. Duduković, D. J. Lee, Liang Shih Fan

Chemical and Biochemical Engineering Faculty Research & Creative Works

The Hydrodynamics of a 10-Cm-Diameter Cylindrical Bubble Column at the Superficial Gas Velocity of 2, 4, and 8 Cm/s Are Investigated by Computer-Automated Radioactive Particle Tracking (CARPT), Particle Image Velocimetry (PIV), and Computed Tomography (CT). These Experimental Techniques Are Capable of Providing the Knowledge of Velocity and Holdup Fields in a Bubble Column System, Which Are Essential as the Experimental Benchmark for Modeling of Such Systems. the Flow Field of Liquid Phase, as Well as the Reynolds Stresses, Obtained by CARPT and PIV in an Air-Water System Are Compared in Detail. the Results Indicate that CARPT and PIV Complement Each …

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Parametric Study Of Unsteady-State Flow Modulation In Trickle-Bed Reactors, M. R. Khadilkar, M. (Muthanna) H. Al-Dahhan, M. P. Duduković Jul 1999

Parametric Study Of Unsteady-State Flow Modulation In Trickle-Bed Reactors, M. R. Khadilkar, M. (Muthanna) H. Al-Dahhan, M. P. Duduković

Chemical and Biochemical Engineering Faculty Research & Creative Works

Unsteady-State Liquid Flow Modulation (Periodic Operation) Was Investigated for Hydrogenation of Alpha-Methylstyrene to Cumene in a Hexane Solvent over 0.5% Pd on Alumina Spheres. This Test Reaction Was Run under Both Gas and Liquid Reactant-Limited Conditions. It is Shown that Periodic Liquid Flow Modulation Can Alter the Supply of Liquid and Gaseous Reactants to the Catalyst and Result in Reactor Performance Different from that Obtained under Steady-State Conditions. the Effect of Key Parameters Such as Extent of Gas/liquid Limitation, Total Cycle Period, Cycle Split, and Liquid Mass Velocity Were Investigated Experimentally to Demonstrate the Cause-Effect Relationships in Periodic Operation. Performance …

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Liquid Holdup Measurement Techniques In Laboratory High Pressure Trickle Bed Reactors, Muthanna H. Al-Dahhan, Wes Highfill Jan 1999

Liquid Holdup Measurement Techniques In Laboratory High Pressure Trickle Bed Reactors, Muthanna H. Al-Dahhan, Wes Highfill

Chemical and Biochemical Engineering Faculty Research & Creative Works

Three Different Techniques, Which Are Tracer, Drainage and Weighing Methods, Are Used to Measure Liquid Holdup in a Laboratory Trickle-Bed Reactor Operated under High Pressure. the Holdup Measurements Are Compared to Determine the Applicability of These Methods at High Pressure Operation. It Was Found that Tracer and Drainage Techniques Give Comparable Values for the Total Liquid Holdup. Although Several Investigators Recommended the Weighing Method over the Others based on their Experiments Performed at Atmospheric Conditions, It Was Found that the Weighing Method Failed to Measure Liquid Holdup Properly at High Pressure Operation.

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Frontal Chromatography Of Proteins: The Effect On Column Performance Of The Restricted Diffusion Of Molecules In Porous Chromatographic Adsorbents, Athanasios I. Liapis, H. Sadikoglu, Orrin K. Crosser Dec 1998

Frontal Chromatography Of Proteins: The Effect On Column Performance Of The Restricted Diffusion Of Molecules In Porous Chromatographic Adsorbents, Athanasios I. Liapis, H. Sadikoglu, Orrin K. Crosser

Chemical and Biochemical Engineering Faculty Research & Creative Works

A theoretical formulation is presented that can be used to describe the dynamic behavior of frontal chromatography of proteins in columns packed with adsorbent particles in which restricted pore diffusion of the adsorbate molecules occurs. The results of this work clearly indicate that the time for breakthrough and the effective utilization of the adsorptive capacity of the chromatographic particles increase as (a) the size of the adsorbate and/or ligand (active site) molecule decreases, (b) the pore connectivity, n(T), of the porous network of the adsorbent particles increases, and (c) the column length, L, increases. Copyright (C) 1998 Elsevier Science B.V.

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Network Modeling Of The Intraparticle Convection And Diffusion Of Molecules In Porous Particles Packed In A Chromatographic Column, J. J. Meyers, Athanasios I. Liapis Dec 1998

Network Modeling Of The Intraparticle Convection And Diffusion Of Molecules In Porous Particles Packed In A Chromatographic Column, J. J. Meyers, Athanasios I. Liapis

Chemical and Biochemical Engineering Faculty Research & Creative Works

A pore network model (cubic lattice network) is constructed to represent the porous structure in a column packed with porous chromatographic particles. Expressions are developed and used to determine, through the utilization of the pore network model, the intraparticle interstitial fluid velocity and pore diffusivity of a solute as the pore connectivity, n(T), of the porous medium is varied from 2.6 to 6.0. The results show that the intraparticle interstitial velocity and the pore diffusivity increase significantly as the value of the pore connectivity, n(T), increases, and clearly indicate that the pore connectivity, n(T), plays a key role in determining …

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Study On The Estimation And Control Of A Liquid Composite Molding Process, Dennis Sourlas, Susmito Naha, Gary Patterson, Richard Parnas Dec 1998

Study On The Estimation And Control Of A Liquid Composite Molding Process, Dennis Sourlas, Susmito Naha, Gary Patterson, Richard Parnas

Chemical and Biochemical Engineering Faculty Research & Creative Works

An on-line nonlinear receding horizon control algortithm is employed in order to achieve setpoint tracking targets in the context of liquid composite molding processes. The robustness of this control strategy against process-model deviations is tested. Finally, recursive parameter estimation is employed as a means of actively enhancing the performance of the process control algorithm. © 1998 AACC.

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Frontal Chromatography Of Proteins. Effect Of Axial Dispersion On Column Performance, G. A. Heeter, Athanasios I. Liapis Feb 1998

Frontal Chromatography Of Proteins. Effect Of Axial Dispersion On Column Performance, G. A. Heeter, Athanasios I. Liapis

Chemical and Biochemical Engineering Faculty Research & Creative Works

A mathematical model describing the dynamic adsorption of proteins in columns packed with spherical porous adsorbent particles is used to study the effect of axial dispersion on the performance of chromatographic systems. The values of the axial dispersion coefficient, D(L), are estimated from a correlation based on a model describing axial dispersion in packed beds that provides satisfactory results when compared with experiment. Simulations of frontal chromatography in systems including axial dispersion and in systems without axial dispersion are made and compared to determine the effect of axial dispersion on the efficiency of the adsorption process; also, the system parameters …

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Investigation Of A Complex Reaction Network: I. Experiments In A High-Pressure Trickle-Bed Reactor, M. R. Khadilkar, Y. Jiang, M. (Muthanna) H. Al-Dahhan, M. P. Duduković, S. K. Chou, G. Ahmed, R. Kahney Jan 1998

Investigation Of A Complex Reaction Network: I. Experiments In A High-Pressure Trickle-Bed Reactor, M. R. Khadilkar, Y. Jiang, M. (Muthanna) H. Al-Dahhan, M. P. Duduković, S. K. Chou, G. Ahmed, R. Kahney

Chemical and Biochemical Engineering Faculty Research & Creative Works

A High-Pressure Trickle-Bed Reactor Was Used to Achieve High Productivity and Selectivity for the Manufacture of a Key Herbicide Intermediate (Α-Aminomethyl-2-Furanmethanol (Amino Alcohol, AA) from Α-Nitromethyl-2-Furanmethanol (Nitro Alcohol, NA). Raney Nickel Catalysts of Varying Activity Were Prescreened for Suitability in Trickle-Bed Operation. the Effect of Operating Parameters Such as Reactant Feed Concentration, Liquid Mass Velocity, and Temperature on the Yield of Amino Alcohol (AA) for RNi-A Are Discussed. the Superiority of Trickle-Bed Reactors over Others Such as Semibatch and Batch Slurry Systems is Demonstrated. the AA Yield Increases with Decrease in Feed Reactant Concentration and Liquid Mass Velocity, as Well …

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