Chemical Engineering Commons^™

First Principles Doping Analysis Of Perovskite- And Ruddlesden-Popper-Based Solid Oxide Fuel Cells, Nicholas Alexander Szaro

Theses and Dissertations

Solid oxide fuel cells (SOFCs) have shown significant promise as a high efficiency energy conversion technology. SOFCs are solid-state, high temperature (600 – 1000 °C), and electrochemical conversion devices that can operate with a wide variety of fuels such as hydrogen, syngas, and hydrocarbon feedstocks. The state-of-the-art SOFC is manufactured with a lanthanum strontium manganite (LSM) cathode, an yttria-stabilizedzirconia electrolyte (YSZ), and a nickel on yttria-stabilized-zirconia (Ni/YSZ) cermet anode. LSM || YSZ || Ni/YSZ SOFCs operate at or above 800 °C to achieve sufficient oxide mobility. The high temperatures introduce problems such as long device start-up, particle sintering, and material …

Revisiting The Volumetric Swing Frequency Response Method For The Determination Of Limiting Mass Transfer Mechanisms Of N2 And O2 In Carbon Molecular Sieve 3k172, Adam Marshall Burke

Theses and Dissertations

Adsorption-based separations processes, along with the adsorbents that enable them, have benefited from a greater particular focus in recent years, following a desire to improve process energy efficiencies and cost economics. One such adsorbent, carbon molecular sieves (CMS), have likewise been a greater focus. CMS materials offer several key practical uses, such as the separation of nitrogen and oxygen, and the removal of carbon dioxide from methane process streams. In order to effectively design and implement an industrial scale process using a CMS material, the behavior of these gases on the chosen material must be known, including the limiting mass …

Dechlorination Of Waste Pvc (Polyvinyl Chloride) Using Hydrothermal Liquefaction Method, Vahab Ghalandari

Theses and Dissertations

In 2019, waste plastic production in the United States (U.S.) amounted to approximately 73 million metric tons. Projections indicate that by 2030, the generation of waste plastic in the U.S. will increase to nearly 90 million metric tons, and by 2060, it is expected to surpass 140 million metric tons. One prominent type of waste plastic is polyvinyl chloride (PVC), characterized by its high chlorine content, making it a halogenated plastic. This dissertation presents a comprehensive investigation of the dechlorination of waste PVC (WPVC) through various hydrothermal liquefaction (HTL) methods to produce environmentally friendly solid and liquid products. In this …

Evaluating The Feasibility Of Bioenergy Production From Single And Mixed Beverage Waste And Sewage Sludge Through An Integrated Hydrothermal Liquefaction-Anaerobic Digestion System, Oluwayinka Michael Adedeji

Theses and Dissertations

Beverage waste and sewage sludge are two of the most generated waste-based biomasses. Recent interest in the hydrothermal liquefaction (HTL) of these wastes pointed to the generation of a byproduct of high dissolved organic carbon [also called aqueous co-product (ACP)]. However, ACP is being discarded which not only increases the environmental footprints of the HTL process but also results in reduced bioenergy potential. Hence, anaerobic digestion (AD) is touted as an effective utilization process of ACP for further bioenergy recovery. This study evaluated the feasibility of producing bioenergy (biocrude and biomethane) from the combination of beverage waste and sewage sludge …

Exploring Senior Chemical Engineering Students’ Approach To Process Safety Decision Making, Jeffrey Saunders Stransky

Theses and Dissertations

Despite investments in chemical process safety education, evidence suggests that engineers’ decision making may contribute to process safety incidents. Currently, limited educational endeavors in process safety decision making exist, raising the need for a better understanding of how to prepare chemical engineering students for industry decisions. This dissertation fortifies current process safety education through three studies involving senior chemical engineering students. Study One developed the Engineering Process Safety Research Instrument (EPSRI) through exploratory and confirmatory factor analyses. Educators may use the EPSRI to evaluate their students’ moral development. Study Two evaluated a digital process safety game, Contents Under Pressure, on …

Effects Of Alternative Jet Fuels On Aerospace-Grade Composites: Experimental And Modeling Studies, Naoufal Harich

Theses and Dissertations

The aviation industry aims to reduce its environmental impact through innovation and research. The usage of composite materials for multiple primary structures represents one such measure. Several alternative fuels were approved and used along with the Federal Aviation Administration (FAA). These alternative fuels are produced from wastes and biomasses. Some alternative fuels were initially only approved as drop-in fuels, meaning they must be blended with conventional fuels to operate. Fuel tanks are usually embedded into the wing structure, which is mainly made of composite materials. These composites tend to absorb fluids it encounters through their matrix phase. The absorption behavior …

Waste Biomass-Derived Ultraporous Functionalized Superactivated Hydrochars For Hydrogen Storage And Carbon Capture, Al Ibtida Sultana

Theses and Dissertations

Accelerating world population and simultaneous growth in economic race has resulted in parallel rise of waste generation where the necessity of mitigating the climate change, via transitioning towards a clean energy economy and minimization of greenhouse gas from atmosphere, is in urgent need of attention. Hence, the objectives of this dissertation comprised of firstly upcycling waste biomass into low-cost and effective adsorbent material such that, secondly, its surface could be tailored by modulating its synthesis conditions (hydrothermal carbonization and chemical activation) to be developed into ultraporous and functionalized adsorption medium in order to, thirdly, assess its application as adsorbents for …

Development And The Use Of A New Kinetically Limited Linear Driving Force Model For Diffusion-Based Adsorptive Separations, Sulaimon Adedayo Adegunju

Theses and Dissertations

A new kinetically limited linear driving force (KLLDF) model, in terms of a modified extended Langmuir (EL) isotherm, was developed. This KLLDF model augments the equilibrium driving force in the linear driving force (LDF) model in such a way that the equilibrium loading of each component in the LDF model depends on the actual, kinetically limited, loading of the other components in a gas mixture, not their partial pressures. In contrast, the LDF model assumes the presence of a slower diffusing adsorbate in a gas mixture affects the equilibrium of a faster diffusing adsorbate in a pore structure via its …

Design Of A Tvsa Cycle For Co2 Removal From Spacecraft Cabins Using A Structured Adsorbent, Pravin Bosco Charles Antony Amalraj

Theses and Dissertations

Pressure Swing Adsorption (PSA) and Temperature Swing Adsorption (TSA) are some of the most used cyclic adsorption technologies that is used for separating gas components from its mixture. Carbon Dioxide Removal Assembly (CDRA) in the International Space Station (ISS) facilitates the continuous removal of CO2 by the cyclic adsorption process. The use of structured adsorbents has drawn attention due its several advantages over traditional beaded adsorbents. This work evaluates the role of different design variables on the effective thermal conductivity of a structured adsorbent bed for its possible application in a temperature swing adsorption (TVSA) process for space applications. The …

New Perspectives And Insights Into Direct Epoxidation Of C3H6 Using O2 And Ag Based Catalysts And Measurement Of Active Ag Site Concentration Of Promoted Ag Catalyst For C2H4 Epoxidation By H2 Pulse Titration Over Oxygen Pre-Covered Surface, Md Masudur Rahman

Theses and Dissertations

Direct epoxidation of C₃H₆ using molecular O₂ and Ag catalysts to produce propylene oxide (PO) selectively is a long-sought goal in the field of heterogeneous catalysis. In the early 1990’s Scientists at ARCO reported promising results of 58 – 59% selectivity to PO at 3.2% conversion of C₃H₆ over an unusual composition of 54.0 wt% Ag, 2.0 wt% K⁺, 0.5 wt% Mo and balance CaCO₃. Feed additives of ethyl chloride (EtCl), nitric oxide (NO) and CO₂ were stated necessary to achieve the claimed high PO selectivities. The roles …

Mathematical Analysis Of Electrochemical Systems, Shiv Krishna Reddy Madi Reddy

Theses and Dissertations

A solid electrolyte interphase (SEI) growth model is developed in a mixed modethat contains solvent diffusion through the SEI layer and corresponding solvent reduction kinetics at the SEI/electrode interface. The governing equations are solved by the Landau transformation, which makes the moving layer fixed to predict the open circuit potential, SEI layer thickness, and capacity loss. The estimated parameters fitted with experimental data from the literature are computed using COMSOL and MATLAB. Results show that the mixed mode model predicts lower capacity loss and thinner SEI layer due to its growth under open circuit conditions than previously reported by others. …

The Impact Of Using Tanks For The Equalization Step On The Performance Of A Psa Process, Behnam Fakhari Kisomi

Theses and Dissertations

The pressure equalization step between two adsorption beds is a key cycle step in many pressure swing adsorption (PSA) processes. It involves connecting two beds together, or two beds and a tank as a medium. The utilization of tanks for equalization in a bed-to-tank-to-bed (BTB) configuration could be advantageous to reduce the number of beds in PSA cycle. In this study, a binary gas mixture A and B, with A more strongly adsorbed than B, was used for the investigation of Stafstrom-type PSA cycles with bed-to-bed (BB) and bed-to-tank-to-bed (BTB) equalization steps using linear isotherm and isothermal equilibrium theory. For …

Enhancing Sustainable Process Designs Through Strategic Material Utilization And Waste Minimization Approaches, John David Chea

Theses and Dissertations

Sustainability is a growing concern as resources are continually depleted for various applications without adequate renewal plans. The resulting impacts on the ecosystem, health, and resource circularity are often overlooked. This research analyzes improvement opportunities at each major stage in a product's life cycle. Raw material acquisition, product synthesis, process waste management, and the fate of a material in the end-of-life phases were examined. The viability of utilizing renewable resources has been demonstrated in this work by extracting bio-based chemicals from underutilized renewable resources at a commercial scale and transforming the extracted resources into polymeric materials. The optimization of raw …

Model Based Systems Engineering Approaches To Chemicals And Materials Manufacturing, Quang Le

Theses and Dissertations

Model-based systems engineering (MBSE) is part of a long-term trend toward model-centric approaches adopted by many engineering disciplines. This work establishes the need for an MBSE approach by reviewing the importance, complexity, and vulnerability of the U.S. chemical supply chains. The origins, work processes, modeling approaches, and supporting tools of the systems engineering discipline (SE) are discussed, along with the limitations of the current Process Systems Engineering (PSE) framework. The case is made for MBSE as a more generalizable and robust approach. Systems modeling strategies for MBSE are introduced, as well as a novel MBSE method that supports the automation …

Mechanisms Of Emulsion Destabilization: An Investigation Of Surfactant, Stabilizer, And Detergent Based Formulations Using Diffusing Wave Spectroscopy, Jordan N. Nowaczyk

Theses and Dissertations

Conventional approaches for studying emulsions, such as microscopy and macroscopic phase tracking, present challenges when it comes to establishing detailed mechanistic descriptions of the impact of emulsifier and stabilizer additives. Additionally, while a combination of sizing methods and macroscopic phase tracking can provide insights into droplet size changes and concentration, the use of multiple measurements can be cumbersome and error-prone. It is the focus of this work, to present a new method for studying water in oil (W/O) emulsions that involves using diffusing wave spectroscopy (DWS) to examine the impact of three different surface stabilizing additives at varying concentrations. By …

Structure And Dynamics Of Lignin In Condensed Phase For Biomass Conversion, Nusrat Jahan

Theses and Dissertations

Lignocellulosic biomass represents the largest potential volume and lowest cost for biofuel and biochemical production. Harnessing the full potential of the lignocellulosic biomass for low-carbon energy requires the knowledge of efficient breakdown and fractionation of its carbohydrates and lignin. Organic solvent pretreatment is recognized as an emerging way ahead because of its inherent advantages, such as the ability to fractionate lignocellulosic biomass into cellulose, lignin, and hemicellulose components with high purity, as well as easy solvent recovery and solvent reuse. Through all-atom MD simulation, we analyze the conformational transition of diverse lignin molecules in varying concentration of Methanol/water , DMSO/water …

Hydrothermal Preprocessing Of Waste Corn Stover Into Advanced Biorefinery Feedstock, Md Tahmid Islam

Theses and Dissertations

Waste corn stover is one of the most abundant agronomic resources in U.S., however, those are either incinerated or unprocessed in the field to avoid high logistical cost, economic forfeiture, and environmental complications. Hydrothermal carbonization (HTC) is a promising thermochemical process that transforms wet biomass like waste corn stover into a solid fuel called hydrochar, process liquid, and process gas. The recycle of process liquid is warranted as the HTC process liquid contains organic acid that would increase the mass yield and fuel quality of the hydrochar by catalyzing the HTC reactions. HTC also promotes the fuel quality by densifying …

Liquid Phase Modeling In Metal Catalysis And In Zeolites, Subrata Kumar Kundu

Theses and Dissertations

Liquid phase processing is often desired for selective product formation, such as during catalytic conversion of biomass, and for purification of waste-water streams. Since the liquid phase environment influences the adsorption properties and reactivity of solid catalysts and porous materials, significant performance changes have been observed as a function of solvent properties for various industrial catalytic and separation processes. There is a need to better understand these solvation effects on processes at solid-liquid interfaces and to develop novel multiscale models that permit one to explore solvation effects on surface catalyzed reactions and during adsorption in porous media such as zeolites. …

Durability Enhancement Of Anion Exchange Membrane Based Fuel Cells (Aemfcs) And Water Electrolyzers (Aemels) By Understanding Degradation Mechanisms, Noor Ui Hassan

Theses and Dissertations

The past several years have seen remarkable progress in renewable energy sources such as solar and wind, showing excellent efficiency and significant cost reduction. The intermittent nature of renewable resources requires them to be integrated with energy storage systems that can hold or convert this excess energy into other forms. Though batteries have been the most popular, it is also possible to store the energy as chemicals and fuels, such as hydrogen (H₂). Hydrogen generation from water electrolysis has been receiving significant attention in recent years. Among the existing water electrolysis technologies, anion exchange membrane electrolyzers (AEMELs) are …

Supported Metal Bifunctional And Bimetallic Catalysts With Precisely Controlled Structures And Properties, Anhua Dong

Theses and Dissertations

In heterogenous catalysis, metallic nanomaterials play vital roles in numerous chemical processes. However, monofunctional catalysts are greatly impeded in their applications especially in the systems including tandem and/or sequential reaction steps. Besides, the catalytic performance can also be greatly influenced by the particle size, morphology, and geometry of the surface metal atoms.

The goal of this work is to synthesize bifunctional or bimetallic nanoparticles with high metal dispersion and homogenous alloys by rational synthetic strategies to facilitate the catalyst function. Strong electrostatic adsorption (SEA) is an effective and facile methodology to produce well dispersed and uniform nanoparticles. Metal-acid bifunctional catalysts …

Towards Environmentally Sustainable, High-Performance, Lightweight Composites For Automotive Applications, Jasmin Zamudio Vasquez

Theses and Dissertations

The increasing public demand in the world automotive industry to improve the environmental sustainability of their manufactured vehicles without sacrificing drivers' comfort and safety and the high cost of lightweight materials have driven researchers to reconsider materials used in the automotive application. Thus, this work aims toward the production of environmentally sustainable, high-performance, lightweight composites, utilizing recycled carbon fibers (RCFs) and pyrolyzed tire particles (PTPs) reclaimed from pyro-gasification of CFRP wastes and end-of-life tires (ELTs), respectively, as reinforcements for cardanol-based epoxy resins. The fabricated composites exhibited rubbery-like behavior at 25 °C. Spectroscopic, rheological, physical, thermal, thermomechanical, and mechanical characterizations were …

Experimental Study On Co2-Sensitive Polyacrylamide As Potential In-Situ Sealing Agent For Co2 Leakage Pathways In Geological Storage Sites, Iris Laihmen Quan Lopez

Theses and Dissertations

As the world pushes for ‘greener’ technologies and carbon neutrality, efforts have focused on creating novel ways to mitigate humankind’s carbon footprint. Carbon capture and storage (CCS) has become a prevalent technique that has proven to be an effective long-term method to safely relocate excess carbon dioxide (CO₂) into subsurface formations. However, CCS is a newer technique which requires constant monitoring due to potential leakage pathways present in CO₂ storage sites; therefore, a preventive approach to seal leakage pathways is recommended. This dissertation explores the potential of CO₂-sensitive polyacrylamide (CO₂-SPAM) as a novel …

Molecular Theoretical Model For Lipid Bilayers: Adsorption Of Lipidated Proteins On Lipid Bilayers As A Function Of Bilayer Composition And Curvature, Shauna Celeste Kennard

Theses and Dissertations

Protein localization on biological membranes is motivated by either highly selective recognition of specific target membrane components or nonspecific attraction to general physical properties of the membrane, such as charge, lipid heterogeneity, and curvature. Here we discuss the interaction between lipidated proteins and lipid bilayer membranes from a comprehensive examination of how features of the membrane and its lipid constituents, including lipid composition, headgroup size, degree of tail saturation, tail length (bilayer thickness), and membrane geometry, affect the adsorption ability of the proteins. Of key importance is the strong interconnection among these compositional and morphological elements of the membrane in …

Understanding The Reaction Kinetics Of Polyurethane Flexible Foam, Caitlin Alma Mckinnon

Theses and Dissertations

Polyurethane flexible foam is used throughout daily life predominantly as cushions for chairs and mattresses. Currently new foams are made through extensive research and development via trial and error. There are many reactions interacting with each other during the polyurethane generation process. The numerous reactions create difficulty in modeling and predicting the physical attributes of a foam. This thesis explores the kinetics associated with each reaction to generate a simple model to understand the reaction kinetics with the addition of some additives. This thesis focused on creating the foams in a real-world environment, including allowing ambient water vapor to be …

Photocatalytic Degradation Of Organic Contaminants By Titania Particles Produced By Flame Spray Pyrolysis, Noah Babik

Theses and Dissertations

Advanced oxidation of organic pollutants with TiO2 photocatalysts is limited due to the wide bandgap of TiO2, 3.2 eV, which requires ultraviolet (UV) radiation. When nanosized TiO2 is modified by carbon doping, charge recombination is inhibited and the bandgap is narrowed, allowing for efficient photodegradation under visible light. Here, we propose a flame spray pyrolysis (FSP) technique to create TiO2. The facile process of FSP has been successful in preparing highly crystalline TiO2 nanoparticles. Using the same procedure to deposit TiO2 onto biochar, the photocatalyst was doped by the carbonaceous material. The morphology, crystalline and electronic structure of the FSP …

A Compact Natural Gas Pyrolysis Reactor For Hydrogen Fueling Stations, Andrew Richard Earls

Theses and Dissertations

With the increasing amount of greenhouse gases causing more natural disasters and sea level rise, there is a clear need for a global energy transition to less polluting fuels. A possible solution to this problem is converting a portion of the transportation sector fuel to hydrogen. In this thesis, the issues associated with such a transition are discussed and reasonable solutions are proposed. Numerous methods of hydrogen production are explored and compared on the basis of electricity consumption and CO2 emission. A plant size of 1250 kg liq. H2/day is chosen based on California regulated hydrogen refueling credits (HRI) that …

Bio-Ionic Liquid Functionalized Hydrogels Towards Smart Tissue Regeneration, Vaishali Krishnadoss

Theses and Dissertations

A blend of scaffolds, biologically active molecules, and cells are required to assemble functional constructs to repair and regenerate damaged tissue or organ via tissue engineering. The scaffold supports cell growth and proliferation and acts as a medium for diverse cellular activities. Even though hydrogel's high-water content and flexible nature make it a pronounced applicant as a scaffold, they exhibit significant technical limitations such as the absence of cell-binding motifs, lack of oxygen, conductivity, adhesive properties, growth of cells in a 3-dimensional (3D) microenvironment. In this thesis, a novel material platform is evaluated and studied to address the concerns mentioned …

Observing And Modeling Water Electrolysis Performance Limitations Attributed To Gas Generation And Porous Media Properties, Joseph S. Lopata

Theses and Dissertations

Water electrolysis has been a simple method of hydrogen production for over two centuries, but the exploration of its nuances is still accelerating. This work compiles numerous mechanisms via which electrolysis efficiency is influenced by phenomena that occur within, adjacent to, and nearby functional porous media. Computational and experimental methods are applied to electrolysis systems to quantify the impact of twophase flow patterns and porous media properties on energy losses, primarily those linked directly to the presence of the gas phase.

First, an introduction to the chemistry and operating principle of water electrolysis is presented and relevant works from the …

Highly Active And Stable Low-Pgm And Pgm-Free Catalysts For Anion Exchange Membrane Fuel Cells, Horie Adabi Firouzjaie

Theses and Dissertations

Anion exchange membrane fuel cells (AEMFCs) have recently seen significant growth in interest as their achievable current density, peak power density, and longevity have been dramatically improved. Though these advances in performance have been important for demonstrating the feasibility of the technology, nearly all AEMFCs reported in the literature have required a relatively high loading of platinum group metal (PGM)- based catalysts at both the anode and cathode electrodes. However, to take command of the low-temperature fuel cell market, AEMFCs cannot simply reach the same performance as incumbent proton exchange membrane fuel cells (PEMFCs), which have had decades of development …

Fundamentals Of Adsorption And Large Scale Pressure Swing Adsorption (Psa) Process Design, Huan Jiang

Theses and Dissertations

This work focused on both fundamental of adsorption and large-scale PSA design. Chapter 1 and 2 addressed the analysis of conditions for formation of adsorption azeotropes in binary systems. Chapter 1 theoretically assessed the necessary and sufficient conditions for the formation of an adsorption azeotrope in a binary gas mixture when this mixture exhibits either intersecting or non-intersecting single gas isotherms. Chapter 2 confirmed theoretically whether adsorption azeotropes can form in a binary mixture at a pressure below the intersection pressure of the corresponding single gas isotherms. Analytical expressions derived for both general and dual thermodynamically consistent process Langmuir (DPL) …