Chemical Engineering Commons^™

Prediction Of Tar And Light Gas During Pyrolysis Of Black Liquor And Biomass, Thomas H. Fletcher, Harland R. Pond, Jarom Webster, Judson Wooters, Larry L. Baxter

Faculty Publications

A generalized model for describing the pyrolysis behavior of low-grade fuels is being developed for incorporation into larger combustion simulation models. Light gas and tar yields from black liquor or biomass pyrolysis can be predicted using the chemical percolation devolatilization (CPD) model originally developed for coal. The initial approach is to measure the average chemical structures in a black liquor sample using 13C NMR spectroscopy. These chemical structures are then used in pyrolysis model predictions. With few changes from the coal-derived kinetic parameters, the model describes the organic pyrolysis behavior of black liquor samples obtained in a nitrogen-purged furnace. It …

Coal Swelling Model For Pressurized High Particle Heating Rate Pyrolysis Applications, Randy C. Shurtz, Joseph W. Hogge, Kade C. Fowers, Gregory S. Sorensen, Thomas H. Fletcher

Faculty Publications

A model was previously developed to describe the decrease in swelling during coal pyrolysis at atmospheric pressure when maximum particle heating rates increase from 10⁴ K/s to 10⁵ K/s. That model included effects of coal type using chemical structure properties. This paper presents results of new experiments to study the effects of elevated pressure and high heating rates on coal pyrolysis. A pressurized flat-flame burner (PFFB) was designed and built to conduct these studies. The pyrolysis experiments reported in this paper were conducted at particle heating rates of ∼105 K/s and maximum gas temperatures of 1700 to 1900 …

Room Temperature Ionic Liquid (Rtil) Membranes For Bio-Methane Dehumidification, Ryan Amos

Electronic Theses and Dissertations

Renewable fuels are heavily researched due to the increasing price of and resulting pollution from fossil fuels. The production of useable energy from waste—animal, sewage, discarded food, landfill matter would be a valuable renewable fuel production method. Biogas is a renewable fuel that is produced by anaerobic digestion, composed mainly of methane, carbon dioxide and small percentages of hydrogen sulfide and water vapor. Before this biogas—predominately bio-methane—can be converted to fuel, it must be dehumidified to become useable. Typically membrane-based gas dehumidification uses hydrophilic polymer membrane materials, such as polydimethylsiloxane (PDMS) and cellulose acetate (CA). The main problems with polymer …

A Fractal Analysis Of The Detection Of Glucose Molecules On Biosensor Surfaces, Lokesh Taneja

Electronic Theses and Dissertations

A fractal analysis for the binding and dissociation of glucose molecules to different biosensor surfaces is presented. The sensors contain immobilized glucose oxidase enzymes that have an affinity for the glucose molecules in solution. Data for different modified biosensors is modeled and analyzed, and a single, dual or triple-fractal analysis is applied where adequate. The binding and dissociation kinetics coefficient where applicable are calculated for each of models along with the fractal dimensions. When both binding and dissociation phases are present, the affinity, K of the receptor to the glucose molecule is calculated and its variation with the fractal dimension …

Thermal And Photochemical Interaction Of Co2 With Biochar, Eneruvie Uyoyou Okinedo

Electronic Theses and Dissertations

With interest in the changes that may occur to the carbonaceous portion of biochar obtain through the pyrolysis of biomass, the simple interaction between CO2 and biochar with water or a mixture of water and ethanol as hydrogen donor resulted in three significant observations. These reactions were carried out thermally at 333K and photochemically by simulating energy from the with a xenon lamp. The photochemical reaction involving biochar, CO2 with water or a mixture of water and ethanol as hydrogen donor led to a decrease in oxygen content of the parent biochar material, as observed by an increase in the …

Limited Thermal Conductance Of Metal-Carbon Interfaces, Jaime J. Gengler, Sergei V. Shenogin, John E. Bultman, Ajit K. Roy, Andrey A. Voevodin, Christopher Muratore

Chemical and Materials Engineering Faculty Publications

The thermal conductance for a series of metal-graphite interfaces has been experimentally measured with time-domain thermoreflectance (TDTR). For metals with Debye temperatures up to ∼400 K, a linear relationship exists with the thermal conductance values. For metals with Debye temperatures in excess of ∼400 K, the measured metal-graphite thermal conductance values remain constant near 60 MW m−2 K−1. Titanium showed slightly higher conductance than aluminum, despite the closeness of atomic mass and Debye temperature for the two metals. Surface analysis was used to identify the presence of titaniumcarbide at the interface in contrast to the aluminum and gold-carbon interfaces (with …

Design Mixers To Minimize Effects Of Erosion And Corrosion Erosion, Julian B. Fasano, Eric E. Janz, Kevin J. Myers

Chemical and Materials Engineering Faculty Publications

A thorough review of the major parameters that affect solid-liquid slurry wear on impellers and techniques for minimizing wear is presented. These major parameters include (i) chemical environment, (ii) hardness of solids, (iii) density of solids, (iv) percent solids, (v) shape of solids, (vi) fluid regime (turbulent, transitional, or laminar), (vii) hardness of the mixer's wetted parts, (viii) hydraulic efficiency of the impeller (kinetic energy dissipation rates near the impeller blades), (ix) impact velocity, and (x) impact frequency. Techniques for minimizing the wear on impellers cover the choice of impeller, size and speed of the impeller, alloy selection, and surface …

Organic Photovoltaics: A Charge Transfer Perspective In The Study Of Donor-Acceptor Pairs, Marco Olguin

Open Access Theses & Dissertations

The present research involves the study of donor-acceptor (D/A) dyad complexes from a charge transfer energy perspective. The aim is to provide insight and predictive understanding into the charge transfer processes of the molecular-level components in donor-acceptor based organic solar cells using computational methods to describe photochemical processes at the quantum mechanical level within the Density Functional Theory (DFT) approximation. Predictive understanding is anchored in reproducing experimental results, wherein the present work a perturbative excited-state DFT method is described in detail and shown to give CT energies in excellent agreement with benchmark experimental data. With an accurate excited state method …

A Review Of Some Subtleties Of Practical Relevance, Keqin Gu

SIUE Faculty Research, Scholarship, and Creative Activity

This paper reviews some subtleties in time-delay systems of neutral type that are believed to be of particular relevance in practice. Both traditional formulation and the coupled differential-difference equation formulation are used. The discontinuity of the spectrum as a function of delays is discussed. Conditions to guarantee stability under small parameter variations are given. A number of subjects that have been discussed in the literature, often using different methods, are reviewed to illustrate some fundamental concepts. These include systems with small delays, the sensitivity of Smith predictor to small delay mismatch, and the discrete implementation of distributed-delay feedback control. The …

Quantifying Cell-To-Cell Variations In Lithium Ion Batteries, Shriram Santhanagopalan, Ralph E. White

Faculty Publications

Lithium ion batteries have conventionally been manufactured in small capacities but large volumes for consumer electronics applications. More recently, the industry has seen a surge in the individual cell capacities, as well as the number of cells used to build modules and packs. Reducing cell-to-cell and lot-to-lot variations has been identified as one of the major means to reduce the rejection rate when building the packs as well as to improve pack durability. The tight quality control measures have been passed on from the pack manufactures to the companies building the individual cells and in turn to the components. This …

Functionalized Silica Materials And Mixed-Matrix Membranes For Environmental Applications, Noah Daniel Meeks

Theses and Dissertations--Chemical and Materials Engineering

Functionalized silica materials are synthesized for various environmental applications. The overall objective is functionalization with sulfur-containing moieties for mercury sorption and as a platform for nanoparticle synthesis. The first objective is quantifying this functionalization for various silica platforms. The second objective is development of effective mercury sorbents, for both aqueous mercury and elemental mercury vapor. Third, those sorbents are incorporated into mixed matrix membranes (MMM) for aqueous mercury sorption. Fourth, functionalized silica materials are developed as platforms for the synthesis of reactive metal nanoparticles (NP) for the degradation of trichloroethylene.

Thiol-functionalized silica is used as a sorbent for aqueous mercury, …

Development Of Strategies To Minimize The Release Of Trace Elements From Coal Waste Sources, Mohammad Rezaee

Theses and Dissertations--Mining Engineering

To assess strategies aimed at minimizing the release of trace elements and the impact of disposal of coal waste materials on the environment, two long-term leaching experiments of up to five months duration were performed using waste materials from two plants cleaning high and low sulfur bituminous coal. The tests evaluated the mobility of major trace elements under different disposal scenarios: (i) a static leaching test designed to simulate the quiescent conditions encountered by coal waste material stored under water in a stable impoundment, and (ii) a dynamic test to simulate waste materials exposed to the atmosphere, either in variable …

Hydrate Formation Using Dowfax Gemini Surfactants, Franchette Viloria

Dissertations and Theses

"Gas hydrate formation is a stochastic and slow process. However, the use of a small amount of surfactant can speed up the rate of hydrate formation. This work investigates the effect of two Dow surfactants, Dowfax 2A1 and Dowfax C6L, on gas hydrate formation, first by determining the adsorption isotherms via liquid-liquid titration methods, and then investigating the role in methane hydrate formation in a non-stirred batch reactor. Both surfactants have almost similar structure, sharing doubly charged headgroups, but these surfactants express different effects on hydrate formation. 2A1 and C6L both show monolayer formation at around concentration of 1.0 mM; …

Measurement Of Interfacial Tension In Hydrocarbon/Water/Dispersant Systems At Deepwater Conditions, Mohamed Abdelrahim

LSU Master's Theses

The events of the Deepwater Horizon oil spill in the Gulf of Mexico were associated with great water depths that made it difficult to understand the behavior of the spilled oil as it came in contact with the seawater. The remedial subsea application of chemical dispersants draws interest to evaluate the interfacial interactions between the oil and water at such great water depths. Most importantly, a quantification of the interfacial tension (IFT) between the spilled oil and seawater at deepwater conditions can provide insight into the effectiveness of the chemical dispersion of spilled oil. In this study, Macondo crude oil …

Synthesis, Characterization, And Testing Of Atomically-Precise Au Clusters Supported On Tio₂ For Co Oxidation, Sarthak Gaur

LSU Doctoral Dissertations

Supported Au catalysts have been studied extensively for CO oxidation. These catalysts are known to catalyze this reaction even at sub-ambient temperatures. While recent literature demonstrates catalytic activity of gold nanoparticles <2 nm, the next stage in fine tuning this catalysis process is to develop gold clusters prepared with atomic precision. Such atomically precise gold catalysts supported on TiO2 hitherto have not been investigated for CO oxidation. The main objective of this work is to synthesize atomically-precise Au38 clusters in a flask-based method using principles of wet chemistry, to characterize these clusters using various advanced spectroscopic techniques, and to test these clusters as potential catalytic materials for CO oxidation. Furthermore, we have tested TiO2-supported Au38 clusters and a commercially purchased Au/TiO2 catalyst for CO oxidation at 30 °C and 60 °C, and used DRIFTS as a probe spectroscopic technique to correlate kinetics with the mechanism occurring on the surface of both catalysts in order to device the mechanistic pathways for CO oxidation. The work reported in this dissertation is the first spectroscopic observation of the phenomena where sulfur may have beneficial effect on the catalytic activity of Au/TiO2 catalysts. Such an interesting observation where sulfur has beneficial effect on catalytic activity of Au/TiO2 catalysts has never been observed in the past. We have also synthesized and tested Fe3O4@Au core-shell nanoparticles supported on TiO2 for CO oxidation. We show for the first time that, core-shell type nanogold catalysts are better suited compared to pure gold nanoparticles for heterogeneous gas phase catalysis of CO oxidation. By conducting comprehensive experiments towards understanding CO oxidation catalysis using X-ray photoelectron spectroscopy, infrared spectroscopy, and temperature programmed reduction, we show that the enhanced catalytic activity is due to a combination of factors ranging from synergistic interaction between Au and Fe, complete removal of organic capping ligands and the presence of metallic gold (Au0) in the active catalyst.

Structural And Dynamical Properties Of Liquid And Solid Phases Of Ionic Liquids Confined Inside Nanoporous Materials, Ramesh Singh

LSU Doctoral Dissertations

The purpose of this research is to investigate the physical properties of ionic liquids (ILs) confined inside nanopores of different materials and morphologies. We are interested to study the effect of pore material, morphology and addition of organic solvents on the properties of confined ILs. Understanding the behavior of ILs inside nanopores is relevant to potential applications of these systems in electrochemical double layer capacitors (EDLCs) and dye sensitized solar cells (DSSCs). Such a fundamental understanding is also crucial to optimize the synthesis of hard-templated 1D nanostructures (nanorods, nanotubes, nanowires) based on organic salts, which may be imparted properties (e.g., …

Efficacy Of Multifunctionalized Saccharide Constructs For The Attenuation Of Amyloid-Beta Toxicity, Dhruva Dilip Dhavale

LSU Doctoral Dissertations

There is evidence that amyloid-beta (Aβ) toxicity is mediated through interactions and binding with neuronal surface sialic acids in Alzheimer’s disease (AD). The binding affinity is higher if the sialic acids are clustered and toxicity of Aβ was attenuated by removal of neuronal sialic acids. Thus, interfering with cell membrane-Aβ binding using biomimetics that could reproduce the clustered sialic acid structure could present us with a potential target for therapeutic intervention in AD. Based on this hypothesis, we developed several multifunctionalized sialic acid labeled chitosan compounds of different valency, or number of sialic acid per chitosan molecule, to attenuate Aβ …

Copper-Cobalt Catalysts For Conversion Of Syngas To Ethanol And Higher Alcohols, Miranda Louise Smith

LSU Doctoral Dissertations

Higher alcohols produced by catalytic conversion of synthesis gas are potential octane enhancers for transportation fuels. Copper-cobalt catalysts have emerged as alternatives to the ethanol-selective, but expensive, rhodium-based ones. The reducibility of the catalyst and the CO adsorption mode are important factors in directing the selectivity of CO hydrogenation toward methanol, hydrocarbons, or higher alcohols. In this study, Cu/SiO2, Co/SiO2, and bimetallic CuCo/SiO2 catalysts, as well as their tin-promoted analogues, were synthesized and characterized by TPR, in situ XRD, in situ XANES, and in situ DRIFTS. Cobalt addition to Cu/SiO2 created an amorphous fraction of CuO that was more easily …

A Study Of The Electrocoalescence On Spherical Droplets In A Flow Focusing Juction Microchannel, Shady A. Habib

Dissertations and Theses

No abstract provided.

A Review Of Offshore Blowouts And Spills To Determine Desirable Capabilities Of A Subsea Capping Stack, Louise Matilde Smith

LSU Master's Theses

The events surrounding the Deepwater Horizon disaster have changed the face of deepwater operations. In order to continue drilling in the Gulf of Mexico, the regulatory body, the Bureau of Safety and Environmental Enforcement (BSEE), has required that applications to conduct work in the Gulf of Mexico (GOM) include a plan to stop, capture, or contain any uncontrolled release of fluids. The capping and containment systems built and implemented by BP during the event are an excellent starting point for minimizing pollution from deepwater subsea blowouts, but the system has limitations. The industry recognizes these limits but is currently focused …