Chemical Engineering Commons^™

Numerical Simulation Of Viscoelastic Buckle Folds: Implications For Stress, Fractures, Porosity And Fluid Flow, Xiaolong Liu

Doctoral Dissertations

"Over the past several decades, buckle folds have been exclusively studied by numerous methods. However, lots of assumptions and simplifications are made, which may not result in realistic in-situ stress conditions leading to rock failure. This study represents the first numerical simulation of folding under the consideration of gravity and pore pressure to simulate the structural development of buckle folds.

The first topic covered in this dissertation is the fracture associated to the single layer fold. It is concluded that burial depth, viscosity, and permeability are critical for the initiation of major fracture sets at the hinge zone with varying …

Mass Transfer Studies In Heavy Oil Recovery Using Solvents, Vijitha Mohan

Doctoral Dissertations

"Heavy oil, sometimes called bitumen, is known for its high viscosity (above 100 cp) and low API gravity (below 22⁰). In most cases, viscosity reduction is needed for the final product. There is a considerable amount of heavy oil in Alberta, Canada and the world's largest heavy oil deposit is in Venezuela. Yet less than 1% of it can be recovered because of its high viscosity. For shallow reservoirs, it is possible to resort to open cast mining. For deeper reservoirs, steam is used at ~ 350 ⁰C which gets the oil viscosity reduced to 1cp, which can now be …

The Effect Of Testing Conditions On Lost Circulation Materials' Performance In Simulated Fractures, Montri Jeennakorn

Doctoral Dissertations

"Lost circulation (LOC) problems increase costs of drilling significantly. It is not only the cost of the drilling fluid that is lost into the formation but also the costs of subsequent problems that can be higher than the cost of the drilling fluids. LOC also possibly leads to a serious risk of blowout incident.

Lost circulation materials (LCM) are regularly added to the drilling fluids with an expectation of plugging the flow path. Due to the difficulties of testing and monitoring LCM sealing processes in the field, LCM evaluation in the laboratory is often used to prove and assure successful …

Immobilization Of Cellulase For Large Scale Reactors To Reduce Cellulosic Ethanol Cost, Dezhi Zhang

Doctoral Dissertations

Cellulosic ethanol is an alternative renewable energy source. Cellulase used in the production of cellulosic ethanol is very expensive. The difficulty in separating cellulase from the cellulose solution after the hydrolysis process limits the reusability of the cellulase, which highly precludes the scales of this application because of the high cost of the enzyme. Immobilization of cellulase provides a promising approach to allow the enzyme to be recycled, thus reducing the production cost. This research focused on immobilizing cellulase for reuse to reduce the cellulosic ethanol cost.

Four immobilization techniques were explored for the immobilization of cellulase on four different …

Manufacturing Polyacrylonitrile Nanowires And Nanofibers For Sensing And Energy Storage Applications, Juan Chen

Doctoral Dissertations

A novel flow guided assembly approach is presented to well align and accurately position nanowire arrays in pre-defined locations with high throughput and large scale manufacturing capability. In this approach, polyacrylonitrile (PAN)/N, N-dimethylformamide (DMF) solution is first filled in an array of microfluidic channels. Then a gas flow is introduced to blow out most solutions while pushing a little leftover against the channel wall to assemble into polymer nanowires. In this way, highly-ordered nanowires are conveniently aligned in the flow direction and patterned along both sides of the microchannels. In this study, we demonstrated this flow-guided assembly process by producing …

Analysis And Mitigation Of Wellbore Breakout And Fracturing, Reza Rahimi

Doctoral Dissertations

"Mechanical wellbore integrity problems while drilling are mainly due to wellbore shear failure or tensile failure. To ensure wellbore integrity, breakout and fracture geomechanical analysis is conducted to estimate minimum and maximum drilling fluid densities. Currently, there is no agreement as to which rock failure criterion to use for estimating breakout or fracture criteria to use for analyzing drilling induced fractures. However, when wellbore integrity issues arise while drilling, mitigation strategies can be applied to rectify these problems.

This dissertation analyzes criteria for wellbore breakout and fracturing. Also, mitigation strategies for breakout and fracturing while drilling were experimentally investigated. Thirteen …

Modeling Gas Inflow For Extremely Low Permeability Shale Using Cfd, Chatetha Chumkratoke

Doctoral Dissertations

"Computational fluid dynamics (CFD) has been used to model 2-D well inflow over a range of permeabilities to study the impact of various well completion strategies (Augustine, 2011). Augustine's 2-D model was subsequently extended for 3-D flow by Thepporprapakorn (2013), for gas flow in the permeability range of tight gas (0.01 mD).

This work presents a 3-D CFD model of gas inflow valid for extremely low ranges of permeability (0.00001 mD). In extremely low permeability, gas flow is complex and includes flow from fractures, flow through porous media, and diffusive gas transport. Diffusive gas transport is important when strong density …

Nanostructured Materials Prepared By Atomic Layer Deposition For Catalysis And Lithium-Ion Battery Applications, Rajankumar Patel

Doctoral Dissertations

"Atomic/molecular layer deposition (ALD/MLD) has emerged as an important technique for depositing thin films in both scientific research and industrial applications. In this dissertation, ALD/MLD was used to create novel nanostructures for two different applications, catalysis and lithium-ion batteries.

MLD was used to prepare ultra-thin dense hybrid organic/inorganic polymer films. Oxidizing the hybrid films removed the organic components and produced the desired nanoporous films. Both porous alumina and titania films can be prepared by such a way. A novel nanostructured catalyst (Pt/SiO₂) with an ultra-thin porous alumina shell obtained from the thermal decomposition of an aluminium alkoxide film …

Study Of Heat Transfer Phenomenon During Natural Convection, Muhammad Yousaf

Doctoral Dissertations

"The purpose of the present study was to numerically investigate the effects of the roughness elements on the heat transfer during natural convection. A computational algorithm was developed based on the Lattice Boltzmann method to conduct numerical study in two-dimensional rectangular cavities and Rayleigh-Bénard cell. A single relaxation time Bhatnagar-Gross-Krook model of Lattice Boltzmann method was used to solve the coupled momentum and energy equations in two-dimensional lattices. Computational model was validated against previous benchmark solutions, and a good agreement was found to exist. A Newtonian fluid of Prandtl (Pr) number 1.0 was considered for this numerical study. The range …

Advancing Microalgae Culturing Via Bubble Dynamics, Mass Transfer, And Dynamic Growth Investigations, Aastha Ojha

Doctoral Dissertations

"The major hindrances to large scale cultivation of microalgae are the problems associated with the design, operation, and scale-up of airlift photobioreactors (PBRs), due to a lack of a comprehensive understanding of the gas-liquid interaction process in real microalgae cultures. Thus, the overall objective of this work is to advance the fundamental understanding of microalgae culturing via gas holdup, bubble dynamics, mass transfer, and dynamic growth investigations.

First, a four-point optical fiber probe technique was employed to study the local gas holdup, and bubble dynamics properties such as bubble passage frequency, chord length and bubble velocity distribution, and interfacial area …

Modeling Of Rheological Properties For Entangled Polymer Systems, Nilanjana Banerjee

Doctoral Dissertations

"The study of entangled polymer rheology both in the field of medicine and polymer processing has their major importance. Mechanical properties of biomolecules are studied in order to better understand cellular behavior. Similarly, industrial processing of polymers needs thorough understanding of rheology so as to improve process techniques. Work in this dissertation has been organized into three major sections. Firstly, numerical/analytical models are reviewed for describing rheological properties and mechanical behaviors of cytoskeleton. The cytoskeleton models are classified into categories according to the length scales of the phenomena of interest. The main principles and characteristics of each model are summarized …

Wetting Kinetics In Forced Spreading, Amer Mohammad Al-Shareef

Doctoral Dissertations

"Under dynamic conditions, the dynamic contact angle (the angle that the liquid makes with the solid) of a liquid on a solid surface varies dramatically with substrate velocity from its equilibrium value. Experimental data of the dynamic contact angles for polydimethylsiloxane (PDMS or silicone oil) under air on a glass substrate coated with teflon, for water under PDMS, for solutions of the polymer polyethylene oxide (PEO) under air, for solutions of PEO under PDMS, were obtained to simulate and understand the systems of brine or brine containing a polymer displacing viscous crude. A variety of solid substrates were used other …

Modeling And Evaluation Of Moisture Diffusion In Polymer Composite Materials, Zhen Huo

Doctoral Dissertations

"Fiber-reinforced polymer composites have extensive applications due to their high specific strength, improved product performance, low maintenance and design flexibility. However, moisture absorbed by polymer composites during the service life plays a detrimental role in both the integrity and durability of composite structure. It is essential to understand the moisture diffusion behavior and induced damage in polymer matrix composites under varying hygrothermal conditions. In Part I, the moisture diffusion characteristics in hybrid composites using moisture concentration-dependent diffusion method have been investigated. Also, a multi-stage diffusion model was proposed to explain the deviation of moisture diffusion behavior for sandwich composites from …

Scale-Up Investigation And Hydrodynamics Study Of Gas-Solid Fluidized Bed Reactor Using Advanced Non-Invasive Measurement Techniques, Abdelsalam Efhaima

Doctoral Dissertations

"This research focuses on validating our newly developed mechanistic scale-up methodology for hydrodynamics similarity of gas-solid fluidized bed reactors (FBRs) by implementing our advanced non-invasive measurement techniques which are gamma ray computed tomography (CT) and radioactive particle tracking (RPT) that measure local hydrodynamic parameters. Experiments were carried out in two fluidized beds of 14 cm and 44 cm in diameter using air as the gas phase and particles of different materials. Since in these reactors the gas dynamic dictates the bed hydrodynamics, the new mechanistic scale-up methodology is based on maintaining similar or closer time averaged radial profiles of gas …

Design, Fabrication, Operation And Aspen Simulation Of Oil Shale Pyrolysis And Biomass Gasification Process Using A Moving Bed Downdraft Reactor, Hassan Golpour

Doctoral Dissertations

"Energy is the major facilitator of the modern life. Every developed and developing economy requires access to advanced sources of energy to support its growth and prosperity. Declining worldwide crude oil reserves and increasing energy needs has focused attention on developing existing unconventional fossil fuels like oil shale and renewable resources such as biomass. Sustainable, renewable and reliable resources of domestically produced biomass comparing to wind and solar energy is a sensible motivation to establish a small-scale power plant using biomass as feed to supply electricity demand and heat for rural development. The work in Paper I focuses on the …

Modeling Explosive Lensing On A Cylindrical Body In Air: A First Step Towards Sealing An Underwater Offshore Oil Spill, Phillip R. Mulligan

Doctoral Dissertations

"In 2010, the British Petroleum (BP) Deepwater Horizon accident leaked oil into the Gulf of Mexico for 87 days. A fast response method that can seal an oil pipe and stop the release of oil is needed in order to prevent future oil leaks from turning into ecological and financial disasters. Explosives can serve this need.

This research examined how a circular implosive discontinuous explosive lens interacts with a cylindrical surface. The following research was designed to study the applicability of the Method this author developed to predict the peak pressure from multiple shockwaves converging on a centrally located cylinder. …

Development And Evaluation Of A Coaxial Cable Sensing System For Co₂ Sequestration Wellbore Integrity Monitoring, Yurong Li

Doctoral Dissertations

"Downhole monitoring plays a crucial part in geological carbon dioxide (₂) sequestration. Various downhole monitoring technologies have been explored and applied, but they are either expensive or have system longevity issues. To address this issue, a robust and cost-effective downhole sensing system based on distributed coaxial cable sensors is developed and evaluated in laboratory, and a numerical simulation with staged finite element model is conducted to study the feasibility of using the coaxial cable sensing system for monitoring and evaluation of wellbore stability during CO₂ injection.

The real-time distributed sensing system is composed of Fabry-Perot interferometer based …

Gold Nanoparticle Enhancements In Electroporation Mediated Dna And Rna Therapeutics, Shuyan Huang

Doctoral Dissertations

Nonviral gene delivery methods have been explored as the replacement of viral systems for their low toxicity and immunogenicity. However, they have yet to reach levels competitive to their viral counterparts. Electroporation figured prominently as an effective nonviral gene delivery approach for its balance on the transfection efficiency and cell viability, no restrictions of probe or cell type, and operation simplicity. The commercial electroporation systems have been widely adopted in the past two decades but still carry drawbacks associated with the high applied electric voltage, unsatisfied delivery efficiency, and/or low cell viability. What we did was to improve electroporation performance …

Diamond Mems Biosensors: Development And Applications, Wenli Zhang

Doctoral Dissertations

This research focuses on the development a dielectrophoresis-enhanced microfluidic impedance biosensor (DEP-e-MIB) to enable fast response, real-time, label-free, and highly sensitive sensor for bacterial detection in clinical sample. The proposed design consists of application of dielectrophoresis (DEP) across a microfluidic channel to one of the impedance spectroscopy electrodes in order to improve the existent bacterial detection limits with impedance spectroscopy. In order to realize such a design, choice of electrode material with a wide electrochemical potential window for water is very important. Conventional electrode material, such as gold, are typically insulated for the application of DEP, and they fail when …

Functional Clay Nanotubes And Composites, Yafei Zhao

Doctoral Dissertations

Tubular nanomaterials and their composites have been extensively studied in recent years in the fields of physics, chemistry, biology, and biomedicine. Carbon nanotube is the most commonly studied tubular nanomaterial; however, toxicity and high cost make it less attractive in industry and thus restricts its applications. Halloysite nanotubes, which are available in abundance in the United States as well as in other countries around the world, is a low-cost, unique and versatile aluminosilicate mineral with a chemical formula of Al4Si4O10(OH)8·nH2O. Basically, the halloysite tube diameter is around 50 nm and the length varies with different locations ranging from 0.4-1.5 μm. …

Numerical And Field Data Analysis Of Drill Stem Vibration, Mohammed Fayez Al Dushaishi

Doctoral Dissertations

"Drill stem vibration is a major cause of premature failure of drill stem components and drilling inefficiency. In severe cases, drill stem vibration may lead to wellbore instability that could lead to increased operational cost. Drill stem vibrations are affected by design decisions and the drilling environment. Examples are; bottom hole assembly configurations, selection of operational parameters, and frequent changes in lithology. Vibration modeling, analysis of vibration data, and specialized vibration reduction tools are methods in use to prevent and mitigate severe vibrations.

A drill stem vibration model was created using nonlinear strain formulation which couples the axial, lateral and …

Process Design, Dynamics, And Techno-Economic Analysis Of A Sustainable Coal, Wind, And Small Modular Nuclear Reactor Hybrid Energy System, Kyle Lee Buchheit

Doctoral Dissertations

"The availability of cheap electricity is one of the biggest factors for improving quality of life. With the debate on the effects of carbon dioxide emissions continuing, several countries have either implemented or are considering the reduction of emissions through various economic means. The inclusion of a monetary penalty on carbon emissions would increase the prices of electricity produced by carbon-based sources. The push for large-scale renewable sources of energy has met problems with regards to energy storage and availability. The proposed coal, wind, and nuclear hybrid energy system would combine a renewable energy source, wind, with traditional and stable …

Particle Gel Propagation And Blocking Behavior Through High Permeability Streaks And Fractures, Abdulmohsin Imqam

Doctoral Dissertations

Water channeling, one of the primary reservoir conformance problems, is caused by reservoir heterogeneities that lead to the development of high-permeability streaks and fractures. These streaks and fractures prevent large amounts of oil from being recovered. The ultimate objective of this research was to provide comprehensive insight into designing better particle gel treatments intended for use in large openings, including open fractures, high permeability streaks, and conduits to increase oil recovery and reduce water production.

An intensive laboratory study was conducted to better understand the injection and placement mechanisms of millimeter and micron size preformed particle gels (PPGs) through thief …

Investigation Of Lost Circulation Materials Impact On Fracture Gradient, Mortadha Turki Alsaba

Doctoral Dissertations

"Lost circulation is a challenging problem to be prevented or mitigated during drilling. Lost circulation treatments are widely applied to mitigate losses using a corrective approach or to prevent losses using preventive approaches, also known as "wellbore strengthening". The disagreement among the different wellbore strengthening theories and the lack of understanding the strengthening mechanism resulted in the absence of a standardized method to evaluate the effectiveness of lost circulation materials (LCM) for wellbore strengthening application.

An extensive experimental investigation was performed by constructing a high pressure LCM test apparatus to investigate the effects of different parameters on the sealing efficiency …

Flow Mechanisms And Numerical Simulation Of Gas Production From Shale Reservoirs, Chaohua Guo

Doctoral Dissertations

"Shale gas is one kind of the unconventional resources which is becoming an ever increasing component to secure the natural gas supply in U.S. Different from conventional hydrocarbon formations, shale gas reservoirs (SGRs) present numerous challenges to modeling and understanding due to complex pore structure, ultra-low permeability, and multiple transport mechanisms.

In this study, the deviation against conventional gas flow have been detected in the lab experiments for gas flow through nano membranes. Based on the experimental results, a new apparent permeability expression is proposed with considering viscous flow, Knudsen diffusion, and slip flow. The gas flow mechanisms of gas …

Investigating New Accident Causation, Risk Assessment, And Mitigation Strategy Selection Tools In The Petroleum Industry, Mohammad A. Alkazimi

Doctoral Dissertations

"The inherent complexity of the processes and the volatile nature of petroleum products compel the petroleum industry to continually seek and develop tools and techniques to identify, evaluate, and mitigate potential risks that can negatively impact their process operations. Additionally, government agencies and nonprofit professional societies guide the petroleum industry with regulatory guidelines, standards, and recommended best practices. The industry and these agencies and societies work to improve operational management, to ensure safe working conditions, and to minimize risk of all kinds, so that if failures occur, damage is contained within tolerable limits (Health and Safety Executives, 2013).

The currently …

Analysis Of Production And Pressure Data To Characterize The Performance Of Oil And Gas Reservoirs, Abuagila Ramadan Elgmati

Doctoral Dissertations

"Production data analysis is an important tool for estimating important reservoir parameters. In particular, determining the average reservoir pressure (p_av) and tracking its change with time is critical to analyzing and optimizing reservoir performance. The traditional method for determining p_av involves pressure buildup tests. A direct method for estimating (p_av) from flowing pressures and rate data is available. However, the method is for an idealized case that assumes constant production rate during pseudo steady-state (PSS) flow, which is not generally true for real wells. This research extends that approach so that it can …

Computational Study Of Sodium Magnesium Hydride For Hydrogen Storage Applications, Fernando Antonio Soto Valle

Doctoral Dissertations

Hydrogen offers considerable potential benefits as an energy carrier. However, safe and convenient storage of hydrogen is one of the biggest challenges to be resolved in the near future. Sodium magnesium hydride (NaMgH 3) has attracted attention as a hydrogen storage material due to its light weight and high volumetric hydrogen density of 88 kg/m3. Despite the advantages, hydrogen release in this material occurs at approximately 670 K, which is well above the operable range for on-board hydrogen storage applications. In this regard, hydrogen release may be facilitated by substitution doping of transition-metals. This dissertation describes first-principles computational methods that …

Study And Development Of Sulfated Zirconia Based Proton Exchange Fuel Cell Membranes, Brittany Wilson Kemp

Doctoral Dissertations

With the increasing consumption of energy, fuel cells are among the most promising alternatives to fossil fuels, provided some technical challenges are overcome. Proton exchange membrane fuel cells (PEMFCs) have been investigated and improvements have been made, but the problem with Nafion®, the main membrane for PEMFCs, has not been solved. Nafion® restricts the membranes from operating at higher temperatures, thus preventing them from working in small electronics. The problem is to develop a novel fuel cell membrane that performs comparably to Nafion® in PEMFCs.

The membranes were fabricated by applying sulfated zirconia, via template wetting, to porous alumina membranes. …

Multiscale Modeling Study Of Methanol Oxidation By Ion-Modified Mdh Enzymes, Purnima Kharidehal

Doctoral Dissertations

Enzymes have been considered as molecular electrocatalysts due to their extraordinary characteristics such as their ability to accelerate reactions enormously, to operate under physiological conditions, and to produce fewer by-products during a catalytic reaction. However, enzyme based fuel cells have been reported to have power output and stability limitations, which are restricting the use of this kind of fuel cell to small electronic devices. Methanol dehydrogenase (MDH) is one such enzyme, which oxidizes methanol and other primary alcohols to their corresponding aldehydes. The active site of MDH contains a divalent cation (Ca2+), a co-factor pyrrolo-quinoline quinone (PQQ), several amino acids, …