Engineering Commons^™

Elucidating The Properties And Mechanism For Cellulose Dissolution In Tetrabutylphosphonium-Based Ionic Liquids Using High Concentrations Of Water, Brad Crawford

Graduate Theses, Dissertations, and Problem Reports

The structural, transport, and thermodynamic properties related to cellulose dissolution by tetrabutylphosphonium chloride (TBPCl) and tetrabutylphosphonium hydroxide (TBPH)-water mixtures have been calculated via molecular dynamics simulations. For both ionic liquid (IL)-water solutions, water veins begin to form between the TBPs interlocking arms at 80 mol % water, opening a pathway for the diffusion of the anions, cations, and water. The water veins allow for a diffusion regime shift in the concentration region from 80 to 92.5 mol % water, providing a higher probability of solvent interaction with the dissolving cellulose strand. The hydrogen bonding was compared between small and large …

Modeling Of Rotary Packed Beds For Reactive And Non-Reactive Systems, Chinyere Evangeline Ezeobinwune

Graduate Theses, Dissertations, and Problem Reports

Rotary packed beds (RPBs) are used in a wide range of reactive and non-reactive applications. In this research, a 2-d, first-principles, dynamic model of a non-reactive RPB that is used for heat exchange between the outgoing flue gas from a power plant and the incoming air to the boiler/pulverizer of the power plant is developed. A 2-d, first-principles model of a reactive RPB is developed where a functionalized metal-organic framework (MOF) is used for CO₂ capture.

For the non-reactive system, a Ljungstrom-type air preheater (APH) is considered. Existing models for these rotating heat exchangers are typically 1-d. There are …

Synthesis Of Graphene Using Plasma Etching And Atmospheric Pressure Annealing: Process And Sensor Development, Andrew Robert Graves

Graduate Theses, Dissertations, and Problem Reports

Having been theorized in 1947, it was not until 2004 that graphene was first isolated. In the years since its isolation, graphene has been the subject of intense, world-wide study due to its incredibly diverse array of useful properties. Even though many billions of dollars have been spent on its development, graphene has yet to break out of the laboratory and penetrate mainstream industrial applications markets. This is because graphene faces a ‘grand challenge.’ Simply put, there is currently no method of manufacturing high-quality graphene on the industrial scale. This grand challenge looms particularly large for electronic applications where the …

Next Generation Of Applications Of Metal-Organic Frameworks For Energy And Environmental Sustainability, Qian Liu

Graduate Theses, Dissertations, and Problem Reports

My PhD work aimed at using Metal-organic frameworks (MOFs) for mitigating the environmental issues and energy crisis associated with anthropogenic activities. Specifically, we developed robust platforms and/ or systems using MOF as “scaffolds” to allow for model pollutant detection and CO₂ sequestration and benign transformation respectively.

First, I detailed how photocatalytic properties of 2,5-furandicarbocylic acid (FDCA) in its alone and its MOF- integrated form (MIL-160) were used for the first time for the reduction of Ag⁺ at room conditions. Such photocatalytic activities could then be used in user-designed hybrids (i.e., Ag/MIL-160) to form sensorial platforms for prevalent phenol …

Review Of Established And Emergent Methods For The Production Of C4 Olefins, James Matthew Koval

Graduate Theses, Dissertations, and Problem Reports

Current production of C₄ olefins is dominated by naphtha cracking and butane dehydrogenation, but significant research interest is developing in alternate feedstocks due to an abundance of inexpensive natural gas and bioethanol. The current C₄ olefin production methods are costly, make use of already-depleted petroleum resources, and are often hazardous to workers, which forms the impetus for investigation into alternative methods and assessment of their viability as a future means of olefin production. Methods of natural gas conversion to higher order hydrocarbons are discussed, including Fischer-Tropsch synthesis and oxidative methane coupling, each of which could form the first …

Process Modeling And Techno-Economic Analysis Of Thermo-Catalytic Dimethyl Ether Synthesis And Microwave-Based Aromatics Production Technologies From Shale Gas, Chirag Mevawala

Graduate Theses, Dissertations, and Problem Reports

Production of dimethyl ether (DME) and direct non-oxidative methane dehydroaromatization (DHA) to aromatics via conventional and microwave (MW)-assisted processes are investigated in this research. Plant-wide models of the shale gas to DME process with integrated CO₂ capture via direct and indirect synthesis routes have been developed. Optimal parameter estimation, and model validation are undertaken for various sections of the process including the pre-reforming reactor, auto-thermal reforming reactor, DME synthesis reactors, CO₂ capture units and separation sections. A novel DME separation process has been developed for efficient separation of DME, syngas, and CO₂. Plant-wide techno-economic optimization is …