Engineering Commons^™

Catalytic Conversion Of Biomass Derived Syngas To Liquid Fuels Using Fischer-Tropsch Synthesis, Pratibha Sharma

LSU Master's Theses

Biomass gasification and subsequent conversion to liquid hydrocarbons using Fischer-Tropsch synthesis is a promising source of energy in today’s scenario when the focus has shifted from conventional fuels to alternate sources of energy. Biomass derived syngas is different from other sources of syngas such as steam reforming of methane followed by water gas shift, in terms of H2/CO ratio. Biomass syngas is usually hydrogen deficient and contains various impurities which need to be removed prior to Fischer-Tropsch Synthesis. Syngas derived from biomass also differs significantly with the different sources of biomass, gasification process and the cleanup conditions it is subjected …

Digital Image-Based Frameworks For Monitoring And Controlling Of Particulate Systems, Bing Zhang

LSU Doctoral Dissertations

Particulate processes have been widely involved in various industries and most products in the chemical industry today are manufactured as particulates. Previous research and practise illustrate that the final product quality can be influenced by particle properties such as size and shape which are related to operating conditions. Online characterization of these particles is an important step for maintaining desired product quality in particulate processes. Image-based characterization method for the purpose of monitoring and control particulate processes is very promising and attractive. The development of a digital image-based framework, in the context of this research, can be envisioned in two …

Activity Of Halide-Free Flux At Copper And Tin Surfaces, Guoying Qu

LSU Master's Theses

The activity of halogen-free carboxylic acid flux is considered one of the most important aspects in controlling flip chip joint quality recently. In this work, we examined the CuOx removal effectiveness of carboxylic acid solutions at Cu substrates using electrochemical methods at elevated temperatures from 100ºC to 180ºC. Reaction kinetics of CuOx removal were investigated by chronopotentiometry and gravimetric analysis. FTIR was used to study the surface chemistry, and spectrophotometry was used to understand reactant and product solubility. Kinetics of carboxylic acid solution such as adipic acid or maleic acid in polyethylene glycol (PEG) with and without complexing agents such …

Pore-To-Continuum Multiscale Modeling Of Two-Phase Flow In Porous Media, Qiang Sheng

LSU Doctoral Dissertations

Abstract Pore-scale network modeling using 3D X-ray computed tomographic images (digital rock technology) has become integral to both research and commercial simulations in recent years. While this technology provides tremendous insight into pore-scale behavior, computational methods for integrating the results into practical, continuum-scale models remain fairly primitive. The general approach is to run pore-scale models and continuum models sequentially, where macroscopic parameters are simulated using the pore-scale models and then used in the continuum models as if they have been obtained from laboratory experiments. While a sequential coupling approach is appealing in some cases, an inability to run the two …

Effect Of Surfactant On Dynamics Of A Droplet Released In A Quiescent Medium, Abhijit Rao

LSU Master's Theses

During the ‘Deepwater Horizon’ accident, dispersants were used as one of the remediation methods to mitigate the ill effects of oil that entered the water column. The dispersants lower the interfacial tension at the oil-water interface and cause the large oil droplets to disintegrate into finer droplets which remain dispersed in the water column for longer times. A dispersant typically is composed of a surfactant and solvent. Surfactants are chemical compounds which are chiefly responsible for the lowering of interfacial tension at oil water interface. In this study, we have investigated the effect of surfactant on the dynamics of a …

A Feasibility Study Of Multi-Functional Wells For Water Coning Control And Disposal, Lu Jin

LSU Doctoral Dissertations

Although water coning is well understood, it is difficult to control in field operations resulting in low recovery and large volumes of waste produced water. A solution - proposed here - is a multi-functional well with the in-situ bottom water drainage and injection installations - Downhole Water Loop (DWL). Theoretically, DWL greatly improves well performance (for example, a two-fold increase of DWL well’s water drainage rate would increase the critical (water-free) oil rate by 80%). However, DWL has practical limitations that must be quantified for actual well design. The objective of this work is to: (1) find maximum water drainage …

Modeling Foam Delivery Mechanisms In Deep Vadose-Zone Remediation Using Method Of Characteristics (Moc), Alireza Roostapour

LSU Doctoral Dissertations

This study investigates foam delivery mechanisms in vadose-zone remediation by using Method of Characteristics (MoC). In such applications, dry foams are introduced into a porous medium which is initially at low saturation of water (Sw) containing pollutants such as metals and radionuclides. For vadose-zone remediation processes to be successful, the injected aqueous phase should carry chemicals to react with pollutants and precipitate them for immobilization and stabilization purposes. Typical remediation techniques such as water and surfactant injections are not applicable, because of the concerns about downward migration. As a result, understanding foam flow mechanism in-situ is key to the optimal …

Dynamic Modeling Of Channel Formation During Fluid Injection Into Unconsolidated Sands, Sayamik Ameen

LSU Master's Theses

Water injection is widely used for sweeping hydrocarbons in waterflooding operations, and also for maintaining reservoir pressure or disposing waste water. Injection at a high rate is required to maintain the economy of waterflooding projects; however, loss of injectivity is a quite common problem in unconsolidated sand formations like deep water Gulf of Mexico. Well intervention operations, hurricanes, and other issues require frequent shut-downs during the life of offshore wells; in order to minimize deteriorating effect of these shutdowns on wellbore injectivity more accurate modeling of the injection process is needed. Injection of water into a saturated, granular, porous medium …

The Diagnosis Of Well Control Complications During Managed Pressure Drilling, Brian Piccolo

LSU Master's Theses

The constant bottom-hole pressure method of managed pressure drilling is generally expected to reduce well control risks and apply well understood concepts when a kick is taken. Nevertheless, complications, such as operator error, leaks, plugging, equipment failures, and exceeding kick tolerance, can occur during kick circulation. By not properly interpreting the symptoms of a complication, a driller risks the consequences of additional influx, lost circulation or the simultaneous occurrence of both. To address the challenge of diagnosing complications, the implied pit gain (IPG) method is being evaluated as an enhancement to established industry practices. Traditional diagnostic methods attempt to match …

Analytical Modeling And Diagnosis Of Penetration Rate Performance Of Pdc Bits, Reza Rahmani

LSU Doctoral Dissertations

The high cost of drilling deep (15000+ ft) wells, due to slow rate of penetration (ROP) at depth, has severely limited the utilization and economic significance of deep hydrocarbon resources. The overall objective of this study was to obtain a better understanding of the major cause(s) of slow ROP in deep drilling. An analysis of field data demonstrated the impact of the problem and identified shale and limestone as the primary lithologies where slow ROP occurs at depth. Previous researchers have concluded that interactions between rock, drilling fluid, cuttings, and the bit control ROP. More specifically, several researchers have concluded …

Modeling, Simulation And Analysis Of Renewable Energy Production Systems: Application To Multi-Product Biorefineries, Aryan Geraili Nejadfomeshi

LSU Master's Theses

The primary purpose of this research is to investigate the design and modelling of fully integrated processes which utilize renewable feedstock as raw materials and evaluate the alternative technology and possible process integration options for biorefinery processes to select the optimal configuration based on the production yields and economical profit criteria. The case study considered in this work is a lignocellulosic biorefinery plant which has different technology choices for each section of the process and the ability to produce multi-products from lignocellulosic raw materials. We analyzed different scenarios by simulating the superstructures in Aspen Plus. To incorporate more non-linarites in …

An Experimental And Computational Investigation Of Rotating Flexible Shaft System Dynamics In Rotary Drilling Assemblies For Down Hole Drilling Vibration Mitigation, Richard Duff

LSU Doctoral Dissertations

Rotary drilling system vibration has long been associated with damaging the bit, the bottom hole assembly (BHA) and drill string. Vibration has been traditionally measured in the bottom hole assembly, and been closely associated with the resonant behaviors.

This research study proposes an improved physical laboratory model to explore the dynamic behaviors associated with vibration. This model includes contact with the borehole wall allowing a range of stabilization geometries while removing bit-formation interaction effects. The results of exercising the model help develop new insights into both vibration measurement diagnostics and mitigation strategy execution.

Presented here is a review of other …

Aggregation Of Uncontrolled Fluids During Catastrophic System Failures In Offshore Environments, James Thomas Stiernberg

LSU Master's Theses

Safety culture relating to offshore operations has shifted since the Deepwater Horizon blowout and resulting oil spill. This incident has prompted the research of high volume spills during all stages of hydrocarbon exploration and production. This study particularly covers the interactions of wells and offshore networks as they pertain to situations where a release of reservoir fluids to the environment is occurring. Primary concerns of this investigation are stream confluences, leak modeling, and fluid behavior; the first two will be handled with various numerical software packages (OLGA®, CFD, and nodal analyses) while the later will require more rigorous treatment and …

Reaction Of Green Leaf Volatiles As A Source Of Secondary Organic Aerosols In Fog Droplets, Amie Kathryn Hansel

LSU Master's Theses

Green leaf volatiles (GLVs) are a group of biogenic volatile organic compounds (BVOCs) released into the atmosphere by vegetation when plants undergo stress or mechanical damage. BVOCs produce secondary organic aerosol (SOA) in the gas phase; however, their oxidation as a source of SOA in the liquid phase has not been investigated. Once released into the atmosphere, water-soluble GLVs partition into atmospheric water phases such as fog, mist, dew or rain, where they are oxidized by hydroxyl radicals (ÿOH). Photochemical oxidation yields products that are higher in molecular weight, more polar, more oxygenated, and lower in vapor pressure. When the …

Novel Separation Strategy For Processing Biopyrolysis Liquids, Chuanlin Zhao

LSU Master's Theses

The separation of pyrolysis bio-oil is important for its role in upgrading oil quality and acquiring commercial byproducts. A selective separation method for biopyrolysis liquids is developed in this work. Two parts in succession are involved as the first one aims at selectively removing some of the heaviest fractions from bio-oil. Chromatographic adsorption results show that Class C Fly ash and pyrolysis Bio-char have potential for this goal at <300 ºC, byproduct like combined adsorbates / adsorbents could also be used directly in asphalt cement processes. Thereafter, the second part focuses on adsorbing light fractions like lighter acids and aldehydes selectively. Basic (modified) activated carbons display relatively low selectivity at ~250ºC, but they have better selectivity compared to unmodified activated carbons. Thus some carbon-coated mesoporous silica and alumina materials are also prepared for the adsorption of these light compounds in the future. The combination of the two parts of adsorptions would leave behind a middle distillate fraction which is the bio-oil fraction most amenable to catalytic upgrading, to either a fuel or chemical feedstock.

A New Diagnostics Tool For Water Injected Gas Turbines - Emissions Monitoring And Modeling, Mohammed Shafi Syed

LSU Doctoral Dissertations

Natural gas-fired cogeneration systems are commonly used for large-scale industrial energy production – both electricity generation and heat recovery. Industrial cogeneration currently represents about 8% of the U.S. total electricity generation capacity. Plans call for cogeneration to increase to 20% of the generation capacity by the end of 2030 [1, 2]. Industrial cogeneration systems attain both high thermal efficiency and low emissions. The attainment of low emissions from natural gas fired turbines, in particular low NOx emissions, is of considerable environmental importance especially as coal becomes a less favorable fuel source. Our current project addresses emissions and performance modeling of …

Molecular Dynamics Of Ionic Liquids In Nanoporous Electrodes, Nav Nidhi Rajput

LSU Doctoral Dissertations

Molecular dynamics simulations were performed to investigate structural, dynamical and electrical properties of ionic liquids (ILs) confined inside different nanoporous materials. These systems have potential uses in environmental and energy applications. The main goal is to understand how these IL properties are affected by a) characteristics of nanoporous materials such as chemical nature of the pore walls (e.g., carbon, titania), pore size and pore morphology, and b) characteristics of electrolyte, such as amount of IL inside the pores (pore loading) and concentration of organic solvent, in the case of mixtures of ILs with organic solvents. The results obtained in this …

Development Of A Framework For Scaling Surfactant Enhanced Co₂ Flooding From Laboratory Scale To Field Implementation, Gbolahan I. Afonja

LSU Doctoral Dissertations

The efficiency of the use of CO2 as a displacement fluid in oil recovery is hampered by the existence of an unfavorable mobility ratio that is caused by the large difference in viscosity between the injected fluid (CO2) and the reservoir fluids. This viscosity contrast results in early CO2 breakthrough, viscous fingering, gas channeling, and consequently, the inability of CO2 to effectively contact much of the reservoir and the oil it contains. Improvement of sweep efficiency and mobility control in CO2 injection require solutions to these problems. The use of surfactants and other chemical means for mobility control has been …

Sedimentation Of Swarms Of Particles At Low And Moderate Reynolds Numbers, Oladapo Olanrewaju Ayeni

LSU Master's Theses

The sedimentation of a cloud of particles in a viscous fluid at low and moderate Reynolds numbers has been studied using an Eulerian-Lagrangian multiphase flow approach. We looked at the volume fraction dependence of the settling cloud and find a similar dependence in the simulations as in the theoretical predictions of (Nitsche and Batchelor 1997). The average cloud settling velocity and the velocity fluctuations around this average are found to have a functional dependence on ö^1/3 at negligible Reynolds number. The velocity fluctuations display strong anisotropy with the magnitude of the vertical component almost three times the magnitude of the …

Discrete Phase Simulations Of Drilled Cuttings Transport Process In Highly Deviated Wells, Doguhan Yilmaz

LSU Master's Theses

Transporting drilled cuttings from the bottomhole to the surface becomes more difficult and problematic in highly deviated wells than in vertical wells. Cuttings tend to settle down on the low side of the annulus typically in the form of a bed which can cause further problems. The height of this bed depends on many parameters such as annular domain geometry, drilling fluid density and rheology, annular flow rate, drill pipe rotation speed, cuttings size, shape, and their density. Prediction of the stationary cuttings bed height with respect to these aforementioned parameters is thus necessary to optimize the range of the …

Molecular Dynamics Of Interfacial Phenomena At Air/Ice, Air/Water, And Air/Salt Water Interfaces, Thilanga Prabhash Liyana Arachchi

LSU Doctoral Dissertations

The purpose of this research is to investigate the adsorption of organic contaminants, namely polycyclic aromatic hydrocarbons (PAHs) and green leaf volatiles (GLVs), as well as their interactions with reactive oxygen species (ROSs) on atmospheric air/water and air/ice interfaces. In another series of projects, we studied several intermediate and semi-volatile organic compounds from oil (IVOCs and SVOCs, e.g., alkanes with 17-31 carbon atoms), surfactants and dispersants at air/salt water interfaces. These simulations are relevant to understand the fate of these compounds during the recent 2010 Deepwater Horizon (DWH) oil spill. The adsorption of gas-phase aromatics (benzene, naphthalene and phenanthrene), ROSs …

Thermal, Compositional, And Salinity Effects On Wettability And Oil Recovery In A Dolomite Reservoir, Azadeh Kafili Kasmaei

LSU Master's Theses

Low salinity and composition effects in improving oil recovery in sandstone reservoirs are known. However, these effects have not been thoroughly studied for the carbonate reservoirs. Because of the lack of the clay minerals in the carbonate rocks, the mechanisms for the improved oil recovery with low salinity, brine composition, and temperature may not be the same as those for sandstones. This experimental study attempts to investigate the effects of low salinity, brine composition, and temperature on wettability and oil recovery in a dolomite reservoir. Also, it is attempted to confirm that wettability alteration is the main mechanism for improvement …

Structured Materials For Catalytic And Sensing Applications, Selma Hokenek

USF Tampa Graduate Theses and Dissertations

The optical and chemical properties of the materials used in catalytic and sensing applications directly determine the characteristics of the resultant catalyst or sensor. It is well known that a catalyst needs to have high activity, selectivity, and stability to be viable in an industrial setting. The hydrogenation activity of palladium catalysts is known to be excellent, but the industrial applications are limited by the cost of obtaining catalyst in amounts large enough to make their use economical. As a result, alloying palladium with a cheaper, more widely available metal while maintaining the high catalytic activity seen in monometallic catalysts …

Modeling And Design Of Photocatalytic Reactors For Air Purification, Yangyang Zhang

USF Tampa Graduate Theses and Dissertations

Photocatalysis is a promising technique for the remediation of indoor air pollution. Photocatalysis utilizes semiconductor photocatalysts (such as TiO₂ or ZnO) and appropriate light to produce strong oxidizing agents (OH*) that are able to break down organic compounds and inactivate bacteria and viruses. The overall goal of the research is to develop an efficient photocatalytic reactor based on mass transfer for indoor air purification. This study has focused on the enhancement of the effectiveness of the photocatalytic process by the introduction of artificial roughness on the reactor catalyst surface. The major effect of artificial roughness elements on the catalytic …

Model Pt- And Pd-Based Electrocatalysts For Low Temperature Fuel Cells Applications, Selasi Ofoe Blavo

USF Tampa Graduate Theses and Dissertations

In the search for alternative energy technologies, low temperature fuel cells continue to feature as technologies with the most promise for mass commercialization. Among the low temperature fuel cells, alkaline and proton exchange membrane fuel cells are the most popular. Alkaline fuel cells have typically been used for water generation as well as auxiliary power for space shuttles. Their bulkiness however makes them undesirable for other applications, especially in automobiles, where there is a great demand for alternative technologies to internal combustion engines. Proton exchange membrane fuel cells on the other hand possess numerous qualities including their compact size, high …

Development Of Catalytic Technology For Producing Sustainable Energy, Syed Ali Z Gardezi

USF Tampa Graduate Theses and Dissertations

This dissertation explores catalyst technology for the production of renewable liquid fuels via thermo-chemical conversion of biomass derived syngas. Fischer-Tropsch synthesis is a process for converting syngas, i.e. a mixture of CO and H2, into energy rich long chain hydrocarbons and oxygenated compounds. This synthesis process involves a number of elementary reactions leading to an array of polymeric products. The economic operation of an FTS process lie in the interplay of both catalyst and reactor design. In relation to catalysis, the nature of chemisorbed species, and the fractional availability of active metal sites determines rate, conversion and yield. Similarly, reactor …

Kelvin Probe Electrode For Contactless Potential Measurement On Concrete-Properties And Applications, Michael Thomas Walsh

USF Tampa Graduate Theses and Dissertations

The practical feasibility of using a Kelvin Probe as a novel reference electrode in the measurement of both potential and polarization pulse response of reinforcing steel in concrete is demonstrated. Potential values measured using a KP reflect greater stability and repeatability than can typically be attained with conventional reference electrodes. Duplicate reinforced concrete beam test specimens with well-differentiated centrally corroding rebar segments were analyzed using both the Kelvin Probe (KP) and a conventional Saturated Calomel Electrode (SCE). Potential profile maps were developed using potential values recorded under static conditions with both the SCE and the KP. Nominal polarization resistance was …

Application And Characterization Of Self-Assembled Monolayers In Hybrid Electronic Systems, Michael Enoch Celesin

USF Tampa Graduate Theses and Dissertations

In this study, we explore ultra-thin insulators of organic and inorganic composition and their potential role as high-speed rectifiers. Typical applications for these structures include IR sensing, chemical detection, high speed logic circuits, and MEMS enhancements. While there are many elements in the functional group required to create a rectifying antenna (rectenna), the primary thrust of this work is on the rectifier element itself.

To achieve these research goals, a very good understanding of quantum tunneling was required to model the underlying phenomenon of charge conduction. The development of a multi-variable optimization routine for tunneling prediction was required. MATLAB was …

Synthesis Of Titanium Dioxide Photocatalyst With The Aid Of Supercritical Fluids, Haitao Li

USF Tampa Graduate Theses and Dissertations

Titanium Dioxide (TiO2) emerged as one of the most popular photocatalysts since 1970's. However, its photocatalytic activity requires UV irradiation due to its large band gap unless further functionalization or modifications are performed. Furthermore, recovery issue has always been a major drawback, if the more effective form nano particles are utilized.

The key objectives of this research were synthesizing new TiO2 based photocatalyst systems that are effective with both the UV and the visible light while utilizing novel superior environmentally friendly techniques enabling development of nano-structured photocatalysts that can be easily recovered. In this dissertation research, highly porous nano-structured TiO2/WO3/Fe3+ …

One Dimensional Stochastic Coating Growth Kinetics Of Peg 3400 Onto Ammonium Nitrate In A Fluidized Bed, Brandon Smeltzer

USF Tampa Graduate Theses and Dissertations

Fluidized beds represent a cost effective, scalable technology invaluable to the chemical processing community as part of the global scheme of particle design. However, despite wide spread use and multiple approaches (empirical and mechanistic) to modeling a fluidized bed coating process, operations must be done at different scales due to changes within the balance of phenomenological forces (e.g. gravity, buoyancy, drag, surface tension, viscosity, kinetic energy).

Ammonium nitrate is synthetic compound that has multiple applications such as fertilizer, rocket fuel, and self-cooling applications. Ammonium nitrate has five temperature dependent crystal structures that are accompanied by a change in density. The …