Engineering Commons^™

Investigations Of Cost-Effective Biodiesel Production From High Ffa Feedstock, Lesly N. Lesmes Sanchez

Electronic Thesis and Dissertation Repository

Commercial production of biodiesel from refined vegetable oils has been widely practiced. However, more economic raw materials are required in order to make biodiesel competitive in the fuel market. This is a challenge since low-cost lipid feedstock contains high concentrations of free fatty acids (FFA) and water, which inhibit transesterification. This work investigates new catalyst combinations and method configuration to develop a cost-effective and suitable process utilizing refined canola oil and canola oil with high oleic acid content. Results suggest that potassium carbonate is more tolerant to water in the feed and enhances phase separation when compared to traditional catalyst, …

Production Of Lignin-Based Phenolic Resins Using De-Polymerized Kraft Lignin And Process Optimization, Homaira Siddiqui

Electronic Thesis and Dissertation Repository

Commercialization of Lignin-based phenol formaldehyde resins (LPF) has been limited due to the increase in curing temperatures and decrease in adhesive strength of LPF compared to conventional phenolic resins. Lignin depolymerization can increase the reactivity of lignin; however, the effect of lignin molecular weight on curing performance of LPF resins has yet to be investigated. This research work examined the optimization of synthesis parameters including percent substitution of phenol with lignin, formaldehyde- to-phenol ratio (F/P), and Mw of lignin to reduce the curing temperature and increase the adhesive strength of LPF. DSC analysis indicated that lignin with Mw ~1200g/mol resulted …

Studies On Microscopic Flow Structure Inside A Rectangular Circulating Fluidized Bed Through Image Analysis, Jingsi Yang

Electronic Thesis and Dissertation Repository

The microscopic flow structure is studied systematically and comprehensively through a visualization system in a narrow rectangular circulating fluidized bed (CFB) transparent Plexiglas riser with a height of 7.6 m and a cross section of 19 mm × 114 mm. A visualization system consisting of a high-speed video camera, a light source, and image processing and analyzing programs is designed and developed to enable the flow structure to be visualized directly and studied quantitatively. FCC particles of 67 μm are used as the bed materials under different operating conditions with superficial gas velocity (U_g) and solids circulation rate …

A Comprehensive Study Of Cd(Ii) Removal From Aqueous Solution Via Adsorption And Solar Photocatalysis, Samindika Athapaththu

Electronic Thesis and Dissertation Repository

As the increase in industrial technology continue to progress, it results in the increase in heavy metal pollution, creating harmful effects on humans, plants, and animals. Since toxic metals do not degrade easily, they accumulate over time, posing greater danger to living organisms. Removal of these heavy metals is therefore, of great importance. Though many research studies successfully utilized UV photocatalysis with TiO₂ catalyst for the removal of Cd²⁺, none have performed the photoreduction of Cd²⁺ under visible light using eosin-y dye-sensitized TiO₂. The objective of the present research is to study the photocatalytic …

Hydrodynamics In Recirculating Fluidized Bed Mimicking The Stripper Section Of The Fluid Coker, Francisco J. Sanchez Careaga

Electronic Thesis and Dissertation Repository

The stripper section of a Fluid Coker^TM consists of a system of baffles (sheds) that enhances the removal of interstitial and adsorbed hydrocarbon vapors from the fluidized coke-particles. Most of the hydrocarbon-vapors released below a stripper shed flow up to the stripper shed, where they may crack and form coke deposits that foul the shed. Extensive fouling changes the shapes of the sheds, makes them thicker and reduces the free-space between the adjacent sheds until downward solids flow is so impaired that the Coker has to be shut down.

The Radioactive Particle Tracking (RPT) technique allows the determination of …

Oxygen-Free Propane Oxidative Dehydrogenation Over Vanadium Oxide Catalysts: Reactivity And Kinetic Modelling, Sameer Ali Al-Ghamdi

Electronic Thesis and Dissertation Repository

Propane conversion to propylene has been the subject of intensive researches. This is due to the increasing demand for propylene. Current propylene production processes suffer from several limitations. Oxidative dehydrogenation (ODH) is a promising alternative technology for propylene production overcoming the drawbacks of current processes. However, selectivity control in ODH is still a challenge preventing it from an industrial application. This is due to the formation of undesired carbon oxides. Thus, the development of a selective catalyst is crucial for the commercialization of ODH. Vanadium oxide catalysts have been proposed as the most active and selective catalyst for propane ODH. …

Treatment Of Combined Sewer Overflows Using Ferrate (Vi), Rohan Gandhi

Electronic Thesis and Dissertation Repository

Prevention of pollution from combined sewer overflows (CSOs) is currently a major concern due to their impact on aquatic and human environment. With the stringent regulations related to the CSOs treatment, it is necessary to develop an efficient, fast and low cost treatment technique that meets the applicable criteria. In this work, the comprehensive study was done to determine the efficiency of ferrate (VI) for the treatment of CSOs. At a Fe (VI) dose of 0.24 mg/l, TCOD, SCOD, TBOD₅, SBOD₅, TSS, VSS, TP, TN and soluble TN removal efficiencies of 71%, 75%, 69%, 68%, 72%, …

Effects Of Biodiesel Concentration On Microbial Deterioration Of Polyethylene In A Simulated Fuel Storage Tank, Juan Manuel Restrepo-Florez

Electronic Thesis and Dissertation Repository

In this study a simulated fuel storage tank was used to investigate the effect of biodiesel concentration on biodegradation of polyethylene. This research is relevant in the field of fuel storage. The simulated storage system consisted of a number of identical conical flasks. Each flask was comprised of two layers, an upper one consisting of a fuel blend of diesel with biodiesel in concentrations ranging from 0 to 100% of biodiesel and the bottom layer containing an aqueous mineral media inoculated with a community obtained from a real fuel storage facility. Polyethylene slabs cut to a specific size were immersed …

Investigation Of Lysozyme Refolding Using Ionic Liquids As Refolding Additives, Harpreet Kaur

Electronic Thesis and Dissertation Repository

A rapid and inexpensive method for the production of protein is crucial for the biopharmaceutical industry. The bottleneck in the case of genetically engineered systems lies in the recovery of active and properly refolded proteins from inclusion bodies. The correct refolding of a protein from its denatured state is dependent on several parameters including the concentration of the protein, the refolding buffers utilized, the approach employed and finally the type of refolding additives, if any, used in the process.

In this study, an emerging class of refolding additives, namely, ionic liquids were investigated for the refolding of denatured lysozyme protein. …

Study On Fine Powder Coating With Modified Additive, Dangchen Xue

Electronic Thesis and Dissertation Repository

Powder coating is a dry coating technology competing with conventional liquid coatings and offers many benefits such as the elimination of volatile organic compounds, high efficiency of material usage and improved coating durability. However, the rough and thick film surface restricts its wide application. The fine powder coating, which can solve the film quality issues, also has its own limitation: the powder is too cohesive to handle. Although, nanoparticle flow additives can significantly improve the flowability of fine powders, it leads to another obstacle at the same time. Since the inorganic nano additives are not fully compatible with the organic …

Optimisation Of The Transesterification Stage Of Biodiesel Production Using Statistical Methods, Arnold Paintsil

Electronic Thesis and Dissertation Repository

The present research examines solely the transesterification stage of the biodiesel production process. Six process variables that affect the yield of biodiesel at this stage are examined using the 12 run Plackett-Burman Design. To study the effect of FFA[1] and to replicate real life situations where oil (feedstock) contain varying amounts of FFA, linoleic acid is used as FFA and intentionally added to high oleic acid canola oil containing less than 0.07% FFA. The process is catalyzed with potassium carbonate and evaluated at varying temperatures, stirring rates, reaction times and methanol oil ratios. The yields at the end of …

Development And Applications Of A Novel Intermittent Solids Feeder For Pyrolysis Reactors, Federico M. Berruti

Electronic Thesis and Dissertation Repository

This PhD research addresses the challenge of feeding biomass residues into fluidized bed reactors for pyrolysis, through the development of a novel intermittent solid slug feeder, both for laboratory-scale and large-scale reactors. The new feeder can successfully handle biomass residues that are either too cohesive or thermally sensitive for traditional feeders.

To optimize the novel feeder performance, a model for the pulsating solids flow was developed from experimental data collected with ideal slugs, as well as real biomass flow. The model was validated using both a laboratory-scale (< 10 kg/hr) and large-scale feeder (> 250 kg/hr). Several important variables were identified. They include the material flow …

Aging And Stabilization Of Pyrolitic Bio-Oils And Model Compounds, A. G. Manjula Taranganie Siriwardhana

Electronic Thesis and Dissertation Repository

When compared to conventional liquid fuels, bio-oil has several undesired properties such as high viscosity, high acidity, high molecular weight, instability, and phase separation upon aging. Therefore, bio-oil needs further stabilization and upgrading before it can be used as a fuel in engines. Phase separation is considered as one of the major issues because it is detrimental to any fuel application and creates problems in storage, transportation and upgrading of bio-oils. This thesis investigates the phase separation of hardwood derived bio-oil under accelerated aging conditions. Different alcohols are used as stabilizing agents and the minimum required amount of alcohol for …

Pharmaceutical Process Modeling, Optimization, And Control, Ehsan Sheikholeslamzadeh

Electronic Thesis and Dissertation Repository

In this project, the aim was to achieve two important objectives and solve some challenges that the pharmaceutical industry is facing. It will be shown that the NRTL-SAC (Non-random Two Liquid Segment Activity Coefficient) model can best predict the solubility of different pharmaceutical and chemical components in pure and mixed solvents by comparing the results with the well-known model of the UNIFAC. The four parameters that are used in the NRTL-SAC model will be found through nonlinear parameter estimation technique. This project also covers the VLE, LLE, and VLLE phase behaviour calculations using the mentioned models to verify their applicability …

Upgrading Pyrolysis Oil To Produce Liquid Transportation Fuels, Ehsan Reyhanitash

Electronic Thesis and Dissertation Repository

The effects of stabilizing fast pyrolysis oil via catalytic alcohol pretreatment on upgrading via hydrodeoxygenation or thermal treatment was studied by comparing the properties of upgraded-stabilized oils with those of upgraded-non-stabilized oils (benchmarks). The major expected effect was reduction in molar mass of upgraded oils, as stabilization was expected to reduce the reactivity of fast pyrolysis oil, thereby reducing polymerization. It was observed that molar mass reduction was induced by dilution effect of the alcohol rather than reactivity reduction due to stabilization. Also, the effects of different alcohols on stabilization and subsequent upgrading were examined at minimized dilution effect conditions. …

High Density Gas-Solids Circulating Fluidized Bed Riser And Downer Reactors, Chengxiu Wang

Electronic Thesis and Dissertation Repository

A systematic and comprehensive study of hydrodynamics and reactor performance was conducted in a 76 mm i.d., 10 m high riser and a 76 mm i.d., 5.8 m high downer reactor under high density/flux operating conditions using fluid catalytic cracking (FCC) catalyst particles. An optical fiber probe was used to obtain a complete mapping of local solids holdup and particle velocity. Catalytic ozone decomposition reaction was employed to study the characteristics of reactor performance in the CFB riser and downer. The superficial gas velocity (U_g) and the solids circulation rate (G_s) were 3-9 m/s …

Treatment Of Aqueous Biomass And Waste Via Supercritical Water Gasification For The Production Of Ch4 And H2, Izad Behnia

Electronic Thesis and Dissertation Repository

The present study targets to convert aqueous fraction of fast pyrolysis oil into methane and hydrogen gases via supercritical water gasification (SCWG). Water above its critical point is referred to as supercritical water, which has unique properties such as a loss of hydrogen bonding, becoming an excellent solvent for organic compounds. In this thesis, SCWG was used to gasify slurry materials into high calorific gases including CH₄ and H₂. Production selectivity towards more methane or hydrogen was affectively controlled by operational conditions. However, in the absence of catalyst (bank test), gas formation was very minimal. SCWG of …

Numerical Modeling Of Solidification Process And Prediction Of Mechanical Properties In Magnesium Alloys, Mehdi Farrokhnejad

Electronic Thesis and Dissertation Repository

A formulation used to simulate the solidification process of magnesium alloys is developed based upon the volume averaged finite volume method on unstructured collocated grids. To derive equations, a non-zero volume fraction gradient has been considered and resulting additional terms are well reasoned. For discretization the most modern approximations for gradient and hessians are used and novelties outlined. Structure-properties correlations are incorporated into the in-house code and the proposed formulation is tested for a wedge-shaped magnesium alloy casting. While the results of this study show a good agreement with the experimental data, it was concluded that a better understanding of …

Fate Of Estrogens In Anaerobic Digestion And Their Removal In Advanced Oxidation, Shubhajit Sarkar

Electronic Thesis and Dissertation Repository

Estrogenic compounds are most significant endocrine disrupting compounds (EDC), which are of primary concern due to their widespread presence in the aqueous environment and also due to their adverse impact both on aquatic life and potential risk to human health. Conventional wastewater treatment plants are not designed to remove EDC, with biosorption on biosolids as the predominant removal mechanism. Anaerobic digestion is one of the most preferred processes employed for sludge stabilization in wastewater treatment plants. Advanced oxidation processes (AOPs) are seen as promising technologies for removal of estrogens from the environment. In this research, a controlled degradation study of …

Development And Application Of An Experimental Model For The Fluid Coking Process, Carolina B. Morales

Electronic Thesis and Dissertation Repository

Liquid injection into a fluidized bed is used in industrial applications such as the Fluid Coking^TM process for heavy oil thermal cracking. Poor initial liquid-solid contact results in the formation of agglomerates that limit heat and mass transfer processes, reduce the yield of valuable compounds and create operating problems. The present study develops a new experimental model to simulate the complex phenomena that occur when heavy oil is injected in a Fluid Coker through two-phase nozzles. The model is applied in a pilot scale fluidized bed using scaled-down industrial spray nozzles. The experimental results indicate that agglomerate formation slows …

Effect Of Plant Hormones On The Production Of Biomass And Lipid In Microalgae, Malihe Mehdizadeh Allaf

Electronic Thesis and Dissertation Repository

Limited fossil fuel reserves, increasing demand for energy in all parts of the world are some driving forces to look for new sources of transportation fuels. Among different options available, microalgae are currently attracting wide interests as an alternative and renewable fuel source.

Microalgae are single cell photosynthetic organisms that are known for rapid growth and high energy content and as a part of photosynthesis; they produce oil that can be used as a feedstock for biodiesel production. Some algae strains could contain lipid up to 80% of the dry biomass. The amount of lipid production is in direct relation …

Oil-In-Water Emulsification Using Oscillatory Micro-Screen, Jiangshan Liu

Electronic Thesis and Dissertation Repository

A novel emulsification technique has been developed for high throughput production of uniform emulsion droplets using high porosity oscillating stainless steel wire woven micro-screen. Different surfactants were investigated including dispersed/continuous bi-surfactant systems using Span80/SDS and Span80/Tween20. The effects of oscillation amplitude and frequency as well as the dispersed phase flux on emulsion average droplet size and uniformity were investigated. It was found that the droplet average size decreased with increasing the surface sheer stress. The emulsion droplet uniformity determined using the coefficient of variation (CV) changed with oscillations such that there was an optimal oscillating frequency for each amplitude where …

Electrospinning Of Core-Shell Collagen Nanofibers, Ying Li

Electronic Thesis and Dissertation Repository

In tissue engineering, the scaffold plays a critical role in guiding and supporting cells to function and grow optimally. The electrospun nanofibrous scaffold can serve as a near ideal substrate for tissue engineering because it has high surface area and the three-dimensional interconnected porous network can enhance cell attachment and proliferation. Core-shell nanofibrous scaffolds produced with coaxial electrospinning allow bioactive molecule encapsulation to improve cell adhesion, mediate and promote the proper signaling among the cells for their functioning and growth. In the current study, core-shell collagen nanofibers were fabricated via coaxial electrospinning with horizontal and vertical configurations. Core-shell nanofibers with …

Carbon Dioxide Adsorption By Metal Organic Frameworks (Synthesis, Testing And Modeling), Rana Sabouni

Electronic Thesis and Dissertation Repository

It is essential to capture carbon dioxide from flue gas because it is considered one of the main causes of global warming. Several materials and various methods have been reported for the CO₂ capturing including adsorption onto zeolites, porous membranes, and absorption in amine solutions. All such methods require high energy input and high cost. New classes of porous materials called Metal Organic Frameworks (MOFs) exhibit excellent performance in capturing carbon dioxide from a gas mixture.

In the course of the current research, a novel MOF synthesis method using combined microwave and ultrasound, and microwave only was introduced and …

Degradation Kinetics And Functional Design Of Linear Self-Immolative Polymers, Ryan A. Mcbride

Electronic Thesis and Dissertation Repository

Linear self-immolative polymers display a potential to address many of the limitations in the control over the degradation process in traditional biodegradable polymers. These materials are unique relative to most degradable 
polymers, in that they undergo end-to-end depolymerization in
 response to the cleavage of a stabilizing end-capping agent. Although one of their cited 
attributes is a dependence of their degradation time on chain length, no conclusive study has been conducted to demonstrate and study this 
effect. Using a previously reported linear self-immolative backbone derived from alternating 4-hydroxybenzyl alcohol and N,N’-dimethylethylenediamine spacers, this work offers the first conclusive study demonstrating …

Butyl Rubber-Aliphatic Polyester Graft Copolymers For Biomedical Applications: Synthesis And Analysis Of Chemical, Physical And Biological Properties, Bethany A. Turowec

Electronic Thesis and Dissertation Repository

Biomaterials can be used in a wide variety of medical applications owing to their breadth of characteristics that can be imparted by varying their chemical structures. Butyl rubber (IIR), which is a copolymer of isobutylene (IB) and small percentages of isoprene (IP), is particularly attractive as a biomaterial because of its elastomeric mechanical properties, biocompatibility, impermeability and high damping characteristics. IIR is typically vulcanized through chemical-based crosslinking mechanisms. However, these methods are not acceptable for biological applications. This thesis focuses on the synthesis of IIR-polyester graft copolymers by grafting biodegradable and biocompatible polyesters including poly(caprolactone) (PCL) and poly(d,l-lactide) (PDLLA) to …

A Novel Mixed Metallic Oxygen Carrier For Chemical Looping Combustion: Preparation, Characterization And Kinetic Modeling, Mohammad Rezwanul Quddus

Electronic Thesis and Dissertation Repository

In last decades, significant concerns have been raised regarding the global warming effect. To date, about one-third of the total anthropogenic CO₂ emission results from power generation using fossil based fuel and CO₂ is the main contributor to global warming. Therefore, technologies for efficient capture of CO₂ are becoming of great value. In this respect, Chemical-Looping Combustion (CLC) has received significant attention as a promising technology facilitating concurrent CO₂ capture and power generation. This non-conventional technique employs a solid carrier, known as oxygen carrier, to supply oxygen and facilitates combustion process in absence of N_{2 …}

Particle Fluidization In Upward And Inverse Liquid-Solid Circulating Fluidized Bed, Long Sang

Electronic Thesis and Dissertation Repository

The fluidization of particles in upwards and inverse Liquid-Solid Circulating Fluidized Bed is carried out to investigate the hydrodynamic characteristics when using “heavy” and “light” particles, whose densities are higher and lower than that of the surrounding liquid respectively. Generally, the solids are fluidized upwards in the former case, whereas, the downwards fluidization is preferred in the latter scenario.

In the Liquid-Solid Circulating Fluidized Bed (LSCFB) riser, where the upwards fluidization takes place, the effects of particle properties on solids holdup are investigated experimentally based on three parameters: superficial liquid velocity, normalized superficial liquid velocity and excess superficial liquid velocity. …

Sol-Gel Derived Biodegradable And Bioactive Organic-Inorganic Hybrid Biomaterials For Bone Tissue Engineering, Bedilu A. Allo

Electronic Thesis and Dissertation Repository

Treatments of bone injuries and defects have been largely centered on replacing the lost bone with tissues of allogeneic or xenogeneic sources as well as synthetic bone substitutes, which in all lead to limited degree of structural and functional recovery. As a result, tissue engineering has emerged as a viable technology to regenerate the structures and therefore recover the functions of bone tissue rather than replacement alone. Hence, the current strategies of bone tissue engineering and regeneration rely on bioactive scaffolds to mimic the natural extracellular matrix (ECM) as templates onto which cells attach, multiply, migrate and function.

In this …

Catalytic Conversion Of Benzothiophene Over A H-Zsm5 Catalyst, Reactivity And A Kinetic Model, Saad A. Al-Bogami

Electronic Thesis and Dissertation Repository

Nowadays and due to environmental legislations, a world-wide attention has been given towards clean transportation fuels with emphasis on sulfur contents reduction. These efforts on the other hand are challenged by the poor qualities of crude oils. The existing desulfurization technologies such as hydrodesulfurization are not capable to cope with new firm standards. Hence, it is extremely desirable to develop a catalytic desulfurization process to meet both sulfur limits and refining economics. As one aspect of this objective, it is of great importance to study and comprehend the behaviour and chemistry of individual sulfur species present in transportation fuels cuts. …