Engineering Commons^™

Scale-Up And On-Line Monitoring Of Gas-Solid Systems Using Advanced And Non-Invasive Measurement Techniques, Muthanna H. Al-Dahhan, Shreekanta Aradhya, Faraj Zaid, Neven Ali, Thaar Aljuwaya

Chemical and Biochemical Engineering Faculty Research & Creative Works

Industry relies on gas-solid systems for numerous processes. Flow dynamics play an important role in achieving the desired results. The present study proposes, validates and demonstrates a novel mechanistic scale-up approach based on maintaining similar radial profile or cross sectional distribution of gas holdup in two different gas-solid systems in order to achieve hydrodynamics similarity using advanced measurement techniques. This new methodology for scale-up and design has been implemented on gas-solid spouted bed which has been used for drying, granulation and coating. The development can be extrapolated to other gas-solid systems encountered in phosphate processes.

Spatial Moment Analysis Of Reactive And Radioactive Solute In River System With Layered Porous Bed, Shadab Anwar

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Mass exchange between river stream and riverbed is critical towards remediation of contaminated river system. Spatial moment analysis of reactive and radioactive solute in river channel with underlying porous bed is applied to understand the qualitative description of solute plume in riverbed and river stream. Semi-analytical solutions for zeroth-, first- and second-order spatial moment of reactive and radioactive solute are derived in Laplace domain. The spatial moments of concentration are numerically inverted. Parabolic velocity in river channel and exponentially decaying velocity in porous bed are linked using a slip velocity at the interface. The model is verified against the semi-analytical …

Investigating The Effect Of Sio2-Tio2-Cao-Na 2o-Zno Bioactive Glass Doped Hydroxyapatite: Characterisation And Structural Evaluation, Chokchai Yatongchai, Anthony W. Wren, Declan J. Curran, Stuart Hampshire, Mark R. Towler

Chemical and Biochemical Engineering Faculty Research & Creative Works

The effects of increasing bioactive glass additions,

SiO₂-TiO₂-CaO-Na₂O-ZnO up to 25 wt% in increments of 5 wt%, on the physical and mechanical properties of hydroxyapatite (HA) sintered at 900, 1000, 1100 and 1200°C for 2 h was investigated. Increasing both the glass content and the temperature resulted in increased HA decomposition. This resulted in the formation of a number of bioactive phases. However the presence of the liquidus glass phase did not result in increased densification levels. At 1000 and 1100°C the additions of 5 wt% glass resulted in a decrease in density which …

Evaluating N-Benzylgalactonoamidines As Putative Transition State Analogs For Β-Galactoside Hydrolysis, Qui-Hua Fan, Susanne Striegler, Rebekah Langston, James Barnett

Chemistry & Biochemistry Faculty Publications and Presentations

Experimental evidence is provided for p-methylbenzyl-D-galactonoamidine to function as a true transition state analog for the enzymatic hydrolysis of aryl-β-D-galactopyranosides by β-galactosidase (A. oryzae). The compound exhibits inhibition constants in the low nanomolar concentration range (12–56 nM) for a selection of substrates. Along these lines, a streamlined synthetic method based on phase-transfer catalysis was optimized to afford the required variety of new aryl-β-D-galactopyranosides. Last, the stability of the galactonoamidines under the assay conditions was confirmed.

Removal Of Sustained Casing Pressure By Gravity Displacement Of Annular Fluid, Efecan Demirci

LSU Master's Theses

Sustained Casing Pressure (SCP) is the undesirable casing head pressure of a well annulus that rebuilds when bled-down. As the conventional methods for SCP removal using rigs are expensive, there is a need for improvement. Annular intervention for replacing the fluid above the leaking cement with a heavier fluid to stop gas migration is a solution for SCP removal; however, previous attempts failed due to miscibility of injected fluids. Using hydrophobic heavy fluids for the purpose is a newly proposed technique to the technology. Potential of theoretically selected and produced immiscible heavy fluids are investigated in characterized annular fluids. A …

Investigation Of Dimensionality-Dependent Foam Rheological Properties By Using Mechanistic Foam Model, Woochan Lee

LSU Master's Theses

A numerous laboratory and field tests revealed that foam can effectively control gas mobility, improve sweep efficiency, and increase oil production, if correctly designed. It is believed that there is a significant gap between small laboratory-scale experiments and large field-scale tests because of two main reasons: (i) typical laboratory flow tests are conducted in linear systems, while field-scale foam EOR processes are performed in radial (or spherical partly) systems in general; and (ii) through the complicated in-situ lamella creation and coalescence mechanisms and non-Newtonian behavior, foam rheology is thought to depend on geometry and dimensionality and, as a result, it …

Physico-Chemical Properties Of Green Leaf Volatiles, Harsha Satyanarayana Vempati

LSU Master's Theses

Green Leaf Volatiles (GLVs) is a class of vegetation emissions whose release is greatly enhanced in the event of thermal or mechanical stress. These oxygenated hydrocarbons that have been identified as a potential source of Secondary Organic Aerosols (SOA) via aqueous oxidation. The physico-chemical properties of GLVs are vital to understanding their fate and transport in the atmosphere, but few experimental data are available. We studied the aqueous solubility, 1-Octanol/Water Partition Coefficient, and Henry’s Constant (KH) of five GLVs at 25&176;C: methyl jasmonate, methyl salicylate, 2-methyl-3-buten-2-ol, cis-3-hexen-1-ol, and cis-3-hexenyl acetate. Henry’s constant was additionally measured at 30&176;C & 35&176;C, and …

Modeling Of Foam Flow In Porous Media For Subsurface Environmental Remediation, Seungjun Lee

LSU Doctoral Dissertations

Among numerous foam applications in a wide range of disciplines, foam flow in porous media has been spotlighted for improved/enhanced oil recovery processes in petroleum-bearing geological formations and shallow subsurface in-situ NAPL (non-aqueous phase liquid) environmental remediation in contaminated soils and aquifers. In those applications, foams are known to reduce the mobility of gas phase by increasing effective gas viscosity and improve sweep efficiency by mitigating subsurface heterogeneity. This study investigates how surfactant/foam process works fundamentally for environmental remediation purpose by using MoC (Method of Characteristics) based foam modeling and simulation techniques. It consists of two main parts: Part 1, …

Quantifying Phase Configuration Inside An Intact Core Based On Wettability Using X-Ray Computed Tomography, Dinara Dussenova

LSU Master's Theses

The ability to evaluate rock and fluid properties on the order of a few microns opens new areas in reservoir engineering and reservoir simulation. Multiple studies have been done on the application of x-ray computed tomography (microCT) for the pore-scale evaluation of fluid interfaces and rock-fluid interaction. A majority of the fluid flow governing interactions occur at the pore scale level and is usually overseen on large reservoir scales. Hence, it is important to carefully investigate such interactions. Multi-fluid-phase distribution and interaction of two immiscible fluids such as oil and water is one of the most important and constantly investigated …

Experimental Assessment Of Expandable Casing Technology As A Solution For Microannular Gas Flow, Darko Kupresan

LSU Master's Theses

Microannular gas flow in the wellbore is known to be one of the major reasons for Sustained Casing Pressure (SCP). Low success rate (under 50%) of costly remedial cementing operations and increasing difficulty in sealing off problematic areas motivated the industry to look for more practical remediation solutions. Expandable casing technology is one of those new proposed techniques. A bench-scale physical model tested the potential of expandable casing technology for remediation of microannular gas migration. The composite samples with pipe-inside-pipe cemented annulus were designed to simulate a wellbore system including a pre-manufactured microannulus on the inner pipe/cement interface. Multi-rate flow-through …

Numerical Investigation Of Cryopreserved Zebrafish Sperm Cell Activation In Microchannels, Thomas Foster Scherr

LSU Doctoral Dissertations

This aim of this research project is to probe the activation process of zebrafish spermatozoa. Zebrafish are a model species for biological engineering applications, and the cryopreservation of their reproductive cells allows for inexpensive cataloging and maintenance of valuable biological material. Evaluation of cryopreservation protocols for aquatic sperm cells is typically accomplished by motility analysis after subjecting cells to a cryopreservation treatment. In zebrafish sperm cells, motility is initiated when cells come into contact with a hypo-osmotic environment. Subsequent activation analysis is currently done manually and brings with it an inherent difficulty and error. This process is slow and not …

Investigating Different Coding Environments For Simplified Reservoir Characterization Models, Atheer Mohammad Al Attar

LSU Master's Theses

Reservoir characterization is one of the most important tasks that determines the recovery plan for a specific reservoir. This process incorporates a significant amount of data acquisition and processing to finally develop an acceptable model that matches the production history and can forecast the future production behavior. The model also should be able to adapt to changes along the way: adding or removing producers or injectors, changing the injection pattern, recompletions and converting wells are all examples of possible changes that are common in the oil and gas industry. Usually these changes are modeled by running field-scale simulations and providing …

Catalytic Active Site, Mechanistic And Kinetic Studies Of Dry (Co2) Reforming Of Methane Over Lanthanum Zirconate (La2zr2o7) Pyrochlores, Devendra Pakhare

LSU Doctoral Dissertations

Dry (CO2) reforming of CH4 (DRM) produces commercially important synthesis gas (H2 and CO) with H2/CO ≤ 1, which can be used for synthesis of higher alkanes and oxygenates. DRM is highly endothermic and requires temperatures as high as 800°C-1000°C to attain high equilibrium conversions. A major problem associated with DRM is catalyst deactivation due to carbon deposition. Thus it is imperative that the catalyst used for DRM must resist deactivation due to sintering and carbon deposition. DRM is well studied in the literature over various catalysts, however, there is no literature, except the Ashcroft (1993) article, for DRM over …

Continuous Reservoir Modeling Updating By Integrating Experimental Data Using An Ensemble Kalman Filter, Ting Sun

LSU Doctoral Dissertations

The continuous researvoir model updating is widely used to calibrate reservoir simulation models to production data, but many challenges remain. First, few real field data are available to test the new history matching method, and most of the data sets are synthetic cases. Second, computational cost may be high when using non-Gaussian priors or nonlinear models. Third, with large complex models, the simulation runs and history matching method require huge memory allocations. This dissertation achieves a continuous reservoir model updating workflow with a meter-scale , two-phase flow experiment. Both production and seismic data are collected in the experiment. Because the …

Analysis Of Hydrodynamic Drag Forces Acting On Suspended Fine Particle In Porous Media, Seyed Amin Mirsaeidi Farahani

LSU Doctoral Dissertations

An important class of flow and transport problems occurring in porous media involves the interactions between suspended fine particles and the moving fluid at Stokes limit. Historically, due to the complicated geometries of porous media, researchers have had to resort to simplifying assumptions to conceptualize the underlying physics. However, the advent of high performance computing, in recent decades, has made it possible to vigorously investigate this problem at the streamline scale level. In this work, the flow problem is solved by means of a finite-element model. The simulations results are used to compute the drag forces experienced by suspended fine …

Image-Based Pore-Scale Modeling Of Inertial Flow In Porous Media And Propped Fractures, Yijie Shen

LSU Doctoral Dissertations

Non-Darcy flow is often observed near wellbores and in hydraulic fractures where relatively high velocities occur. Quantifying additional pressure drop caused by non-Darcy flow and fundamentally understanding the pore-scale inertial flow is important to oil and gas production in hydraulic fractures. Image-based pore-scale modeling is a powerful approach to obtain macroscopic transport properties of porous media, which are traditionally obtained from experiments and understand the relationship between fluid dynamics with complex pore geometries. In image-based modeling, flow simulations are conducted based on pore structures of real porous media from X-ray computed tomographic images. Rigorous pore-scale finite element modeling using unstructured …

Effect Of Process Mixing On The Size Distribution And Mean Diameter Of The Thiol-Triacrylate Microcapsules, Rubaiyet Abedin

LSU Master's Theses

An important limitation in the development of the microparticles is the difficulty to develop a precise size distribution. Microparticles have a wide spread applicability in different fields including medical, pharmaceutical, textile, cosmetics, pesticide, printing industry, etc. The large and growing impact of microencapsulation in different fields of technology has made this process important. Microparticle size is a primary determinant of control release mechanism and the reaction kinetics and also impacts the allowable routes of administration, The main objective of this research work is to evaluate the effect of the process mixing on the size and size distribution of the trithiol-triacrylate …

Advanced And Novel Modeling Techniques For Simulation, Optimization And Monitoring Chemical Engineering Tasks With Refinery And Petrochemical Unit Applications, Gregory M. Robertson

LSU Doctoral Dissertations

Engineers predict, optimize, and monitor processes to improve safety and profitability. Models automate these tasks and determine precise solutions. This research studies and applies advanced and novel modeling techniques to automate and aid engineering decision-making. Advancements in computational ability have improved modeling software’s ability to mimic industrial problems. Simulations are increasingly used to explore new operating regimes and design new processes. In this work, we present a methodology for creating structured mathematical models, useful tips to simplify models, and a novel repair method to improve convergence by populating quality initial conditions for the simulation’s solver. A crude oil refinery application …

An Experimental Investigation Of The Effects Of N-Decane On The Supercritical Pyrolysis Of Toluene, Catherine A. Grubb

LSU Master's Theses

Future and current high-speed jet aircraft will require their fuels to act as the primary coolants as well as propellants. Fuels will be exposed to severe temperatures and pressures in hypersonic aircraft, up to 700°C and 130 atm, respectively, conditions that are supercritical for most pure hydrocarbons. Under supercritical conditions, hydrocarbon fuels undergo pyrolytic reactions, which may lead to the formation of polycyclic aromatic hydrocarbons (PAH), known precursors to carbonaceous solid deposits. Such deposits may clog fuel lines and injection nozzles, hindering safe engine performance. Hence, it is important to understand the reactions that lead to the formation of PAH. …

Electrochemical Reduction Of Co2 On Supported Cu2o Catalysts, Joel Niño Galvez Bugayong

LSU Doctoral Dissertations

We have examined Cu-based catalyst materials that enable the conversion of CO2 to useful products such as fuels and chemical feedstocks by electrochemical reduction. In particular, we compared the electrocatalytic activity of supported Cu2O particles prepared using electrodeposition and wet chemical methods. The particles had cubic structure, ranging in size from 40 nm to 900 nm and consisting of low index planes. We observed significantly different product distribution on these catalysts compared to polycrystalline Cu, specifically for methane and ethylene formation. While Cu particles showed higher faradaic efficiency for methane formation compared to ethylene formation, we observed that Cu2O particles …

Rare Earth/Transition Metal Oxides For Syngas Cleanup, Rui Li

LSU Doctoral Dissertations

Syngas from gasification of biomass or biomass and coal is a potential source of renewable energy. However, byproducts such as H2S and tars must be removed before further utilization or processing of syngas. Rare earth oxides (REOs, e.g., Ce/LaOx (1.7< x <2)) mixed with transition metals (e.g., Mn, Fe) were synthesized by various methods, and in some cases supported on a thermally stable alumina. Both desulfurization and tar reforming experiments were conducted at high temperatures under similar conditions with synthetic effluents in order to achieve better heat integration and higher yield to desired products CO and H2. The sulfur capacities at temperatures from 900-1025 K with air regeneration were measured for repeat cycles until a stable, reversible capacity was obtained. The oxidized and sulfided (reduced) sorbents were characterized by XRD, XANES, XAFS, TPR and BET. Density functional theory calculations were used to aid in interpreting characterization data and in explaining the enhanced S adsorption capacities. The results showed that mixed REOs, such as Ce/Tb, and Ce/La synthesized by a templated sol-gel approach do not have high sulfur capacities. The presence of either CO2 or H2O inhibits the adsorption of H2S. However, addition of Mn to REOs effectively increased the sulfur capacity, and Mn-REO sorbents are regenerable even in the presence of air, although there is some sulfate formation. The formation of elemental sulfur during regeneration could be related to the oxygen vacancies promoted by doping Mn into the ceria lattice. DFT calculations suggested doping Mn into CeO2 decreased the vacancy formation energies and lowered the H2S adsorption energy. In contrast, for MnO-doped REOs supported on ã-Al2O3, although their surface areas remained high after multi-cycle usage, the probable formation of MnAl2O4 as observed by XANES reduces the sulfur capacities. Reforming experiments were carried out using synthetic syngas mixtures with C10H8 as a tar model compound, both with and without H2S. The results showed that CO2 and H2O inhibit the reforming activities to some extent. Fe- or Mn-doped supported REOs are promising tar cleanup catalysts. They exhibited higher sulfur tolerance, less coking, and less methanation than typical Ni-based high temperature reforming catalysts. This behavior is in part attributed to enhanced generation of oxygen vacancies in the doped REOs.

Effects Of Different Preparation Methods On Structure And Catalytic Behavior Of Iron-Based Catalyst Via Fischer Trospch Synthesis Of Biomass-Derived Syngas, Khietlethanh Mai

LSU Master's Theses

Lignocellulosic biomass is a promising feedstock for producing liquid fuels via synthetic gas (syngas) and Fischer Tropsch Synthesis (FTS). Syngas produced from biomass has low H2/CO ratio (~0.7/1) and high concentration of CO2. In order to produce liquid hydrocarbons from this syngas, a catalyst must be used to increase the H2/CO ratio to 2 or higher. This catalyst must also have reasonable reverse water-gas-shift (R-WGS) activity in a CO2 rich environment. In this study, two 100Fe/4Cu/4K/6Zn were prepared using coprecipitation (Cat_C) and impregnation (Cat_I) methods. The effects of these preparation methods on the catalyst structure and FTS performance in biomass …

Controllable Synthesis Of Dispersed Spherical Fe3O4 Nanoparticles As Lithium-Inserted Materials, Hong-Li Zou, Wei-Shan Li

Journal of Electrochemistry

Dispersed spherical Fe₃O₄ nanoparticles were synthesized by a hydrothermal method. The influences of odecyl trimethyl ammonium bromide (DTAB) concentration on the morphology and particle size of the as-prepared Fe₃O₄ were studied. Electrochemical performance of the as-prepared sample as anode materials of lithium ion battery was investigated. It is found that the as-prepared sample exhibits superior rate performance and cycle performance. The nano-sized materials provide structural stability and favor the transfer of lithium ions.

Synthesis And Electrochemical Performance Of Nano Licopo4 By Polyol Method, Fei Wang, Yang Jun

Journal of Electrochemistry

High potential LiCoPO₄ cathode material was synthesized by polyol method. Carbon layer of ca. 3 nm thick was coated on the LiCoPO₄ surfaces by chemical vapor deposition from methylbenzene. Crystalline structure, morphology and electrochemical performance of the sample were studied by XRD, SEM, TEM, CV and galvanostatic charge/discharge curve. The synthesized material via polyol method showed a pure phase of LiCoPO₄. The LiCoPO₄/C electrode delivered a high discharge capacity of 132 mAh·g^-1 and maintained 78% of the initial capacity after 50 cycles at 0.1C rate. The two-step extraction/insertion behavior of Li⁺ in …

Aqueous Solution-Evaporation Route Synthesis And Phase Structural Research Of The Li-Rich Cathode Li1.23Ni0.09Co0.12Mn0.56O2 By In-Situ Xrd, Chong-Heng Shen, Shou-Yu Shen, Zhou Lin, Xiao-Mei Zheng, Hang Su, Ling Huang, Jun-Tao Li, Shi-Gang Sun

Journal of Electrochemistry

The Li-rich Li_1.23Ni_0.09Co_0.12Mn_0.56O₂ material was synthesized via aqueous solution-evaporation route. The structure and morphology of the material were characterized by means of XRD and SEM. The results indicated that the single particle of the product was polygonal with the size of 330 nm and the structure was layered solid solution with a certain amount of Li₂MnO₃. Electrochemical tests showed that the first discharge capacity of the Li-rich layered material was 250.8 mAh·g^-1 at 0.1C, the capacity retention was 86.5% after 40 cycles. Through in-situ XRD study …

Synthesis And Electrochemical Property Of Li2Fesio4/C Cathode Material By Solid State Method, Jiao-Li Sun, Zhi-Jiao Chen, Yi-Xiao Li, Hu Cheng

Journal of Electrochemistry

Li₂FeSiO₄/C cathode material was synthesized using Li₂SiO₃ and FeC₂O₄ as raw materials by solid state method. The structure and morphology of the material were characterized by XRD and SEM. The electrochemical properties of the material were studied by constant-current cyclic testing. The results show that Li₂FeSiO₄/C has a good electrochemical performance. The first discharge capacity of Li₂FeSiO₄/C cathode material at 30oC reached 167 mAh∙g^-1 when cycled at 10 mA∙g^-1 between 1.5 and 4.8 V.

A Dynamic Optimization Framework With Model Predictive Control Elements For Long Term Planning Of Capacity Investments In A District Energy System, Jose Luis Mojica Velazquez

Theses and Dissertations

The capacity expansion of a district heating system is studied with the objective of evaluating the investment decision timing and type of capacity expansion. District energy is an energy generation system that provides energy, such as heat and electricity, generated at central locations and distributed to the surrounding area. The study develops an optimization framework to find the optimal investment schedule over a 30 year horizon with the options of investing in traditional heating sources (boilers) or a next-generation combined heat and power (CHP) plant that can provide heat and electricity. In district energy systems, the investment decision on the …

A Kinetic Study Of Aqueous Calcium Carbonate, Derek Daniel Harris

Theses and Dissertations

Amorphous calcium carbonate (ACC) precipitation is modeled using particle nucleation, growth, and aggregation. The particles are tracked in terms of their radial size and particle density using direct quadrature method of moments (DQMOM). Four separate nucleation models are implemented and are compared to experimental data. In discord with a recent study, it is shown that classical nucleation, coupled with equilibrium chemistry, is in good agreement with experimental data. Novel nucleation mechanisms are presented which fit the experimental data with slightly greater accuracy. Using equilibrium chemistry it is shown that the equilibrium value of ACC is pKeq = 7.74 at 24C, …

Molecular Modeling Of Dna For A Mechanistic Understanding Of Hybridization, Terry Jacob Schmitt

Theses and Dissertations

DNA microarrays are a potentially disruptive technology in the medical field, but their use in such settings is limited by poor reliability. Microarrays work on the principle of hybridization and can only be as reliable as this process is robust, yet little is known at the molecular level about how the surface affects the hybridization process. This work uses advanced molecular simulation techniques and an experimentally-parameterized coarse-grain model to determine the mechanism by which hybridization occurs on surfaces and to identify key factors that influence the accuracy of DNA microarrays. Comparing behavior in the bulk and on the surface showed, …

Microgrid Development Using A Grid Tie Inverter, Hartono Budi Santoso, Budiyanto Budiyanto

Makara Journal of Technology

The use of renewable energy sources (RES), especially photovoltaic (PV), to meet the demand of electrical energy has been getting a great deal of attention as an alternative solution to electrical energy deficit problems. RES are being applied in power systems in a variety of configurations including microgrid systems. One of the characteristics of a microgrid is capability to supplying power to grid when there is an excess power to supply local load. This research examines the chances of saving power consumption from grid using power converters grid tie inverter (GTI) in a microgrid configuration. The test is done by …