Thermodynamics Commons^™

Comparative Analysis Of Simulation Models Of The Production Of Ethylbenzene, Osariemen Imafidon

Honors Theses

Process Engineering is all about making sure a raw material can become the desired product with as little variation as possible, while achieving the customer's specifications. Many equipment used for chemical processes cannot be physically inspected during operation at steady state, hence, the need for simulation software. The objective of this study was to compare the results of three different simulation packages to evaluate their efficacy within process design.

This study focused on the economic analysis of the production of Ethylbenzene using various models. The base case variables were inputted into each model to simulate the calculations for a fully …

Dry And Wet Torrefaction Of Microalgal Biomass For Biochar Production As Bioenergy Sources, Yong Yang Gan

Student Works (2020-2029)

Increasing population in global and living standards have risen the consumption of global energy. Thermochemical conversion approaches hold great potential for the biomass conversion into energy applications. Among these approaches, torrefaction is a promising technique to enhance the biomass properties, making it more practical and suitable in biofuel applications. In this study, two different species of microalgae (third generation biofuel feedstock) including Chlorella vulgaris ESP-31 and FSP-E were used as feedstocks for dry and wet torrefaction. Dry torrefaction of microalgae was performed at temperatures of 200, 250 and 300 ºC, and holding times of 15, 30, 45 and 60 min, …

Capillary Forces And Wetting Dynamics By Diffuse-Interface Modeling, Fanny Thomas

Dissertations and Theses

Wetting phenomena underlie many natural and industrial processes, from the proper functioning of the lungs to the thin coating of surfaces. The three-phase interactions involved at microscopic scales play a critical role. Adding solid particles to an emulsion, for example, can drastically change the flow behavior due to capillary bridging between the particles. The study of these three-phase systems is especially relevant to the petroleum industry, where gas hydrates forming large clusters in subsea pipelines during crude oil transportation is a major concern. The dynamics of such systems is also of great interest from a fundamental perspective. Indeed describing non-equilibrium …

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 (ETD)

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 …

A Kinetic And Thermodynamic Model Of Ethylene Dichloride Pyrolysis., Travis J Czechorski

Electronic Theses and Dissertations

Ethylene dichloride (EDC) is a precursor for the production of vinyl chloride (VCM) which is subsequently polymerized to form polyvinyl chloride (PVC). To convert EDC to VCM, EDC undergoes a pyrolysis process in the absence of oxygen at temperatures exceeding 500C. However, process yields are limited by the uncontrolled production of side-products that can degrade the quality of PVC and poison the reactor. Thus, tight process controls and costly separations guided by heuristics and plant operator experience are used to optimize EDC pyrolysis. To improve the process, I have programed a kinetic model of EDC pyrolysis based upon estimations of …

Tactical Missile Performance For Single And Multi-Wire Embedded Propellant Configurations With Discontinuities, Paul B. Wilson

Theses and Dissertations

This research analyzes the performance of a nominal air-to-air tactical missile with varying configurations of wire-embedded end-burning solid propellant grains. Single and multi-wire models are developed to determine if total impulse and range is improved. Discontinuities in the wires are simulated to determine if gaps in the wire will affect overall performance. Five wire materials, seven wire diameters, and nine different break locations are tested. This research demonstrates wire discontinuities have negligible impact on performance and carbon nanotube fibers can theoretically improve total impulse by up to 25% compared to radially burning boost-phase grains while providing similar thrust outputs.

Form Stable Phase-Change Materials, Russell Dent, Marjan Kashfipour, Nitin Mehra, Jiahua Zhu

Williams Honors College, Honors Research Projects

This work investigates the use of two different polyols, xylitol (Xyl) and erythritol (Ery), in conjunction with boron nitride (BN) aerogels, for the purpose of creating thermally conductive composites. While the BN filler in Xyl composites achieved a high anisotropic thermal conductivity of up to 4.53 W/m-K at 18.2 weight percent filler loading, they do not exhibit good phase-change material qualities due to a low solidification enthalpy even at low cooling rates. Alternatively, the BN-Ery composites have shown promising results with a solidification enthalpy of 225.14 J/g and a melting enthalpy of 385.84 J/g at a heat rate of 5 …

Removal Of Carbamazepine From Drinking Water, Zachary Wiese

Chemical Engineering Undergraduate Honors Theses

Due to the increasing prevalence of prescription medication over the past few

decades, pharmaceuticals have accumulated in various water sources. This has become a

public health concern because many pharmaceuticals have limited research on the effects

of chronic low-level exposure. According to the World’s Health Organization (WHO),

traces of pharmaceuticals products have been reported in different water sources such as

surface waters, wastewater, groundwater, and drinking water.[1] One pharmaceutical of

interest that has been detected in water sources is carbamazepine. Carbamazepine is a

common pharmaceutical prescribed for the treatment of seizure disorders, neuropathic

pain, and various psychological disorders. It’s mechanism …

Heat, Charge And Spin Transport Of Thin Film Nanostructures, Devin John Wesenberg

Electronic Theses and Dissertations

Understanding of fundamental physics of transport properties in thin film nanostructures is crucial for application in spintronic, spin caloritronics and thermoelectric applications. Much of the difficulty in the understanding stems from the measurement itself. In this dissertation I present our thermal isolation platform that is primarily used for detection of thermally induced effects in a wide variety of materials. We can accurately and precisely produce in-plane thermal gradients in these membranes, allowing for thin film measurements on 2-D structures. First, we look at thermoelectric enhancements of doped semiconducting single-walled carbon nanotube thin films. We use the Wiedemann-Franz law to calculate …

Investigation On The Potential Of A Co2 Capture System, Downstream Of The Aftertreatment System For A Heavy-Duty Engine Application, Murchana Pathak

Dissertations, Master's Theses and Master's Reports

The transportation sector accounts for the second largest source of CO₂ emissions after power generation. New Corporate Average Fuel Economy (CAFE) regulations are focusing on improving energy through reduced fuel consumption and greenhouse gas emissions. This work investigates the potential of a CO₂ capture system downstream of an aftertreatment system for a heavy-duty engine application. Amine absorption has been described as one of the most effective ways to capture CO₂ from the exhaust for point sources. Therefore, using thermal-swing absorption process with potassium carbonate (K₂CO₃) as the absorbent liquid, a process was analyzed …

Effect Of Spalled Particles Thermal Degradation On A Hypersonic Flow Field Environment, Raghava S. C. Davuluri, Huaibao Zhang, Alexandre Martin

Mechanical Engineering Faculty Publications

Two-way coupling is performed between a spallation code and a hypersonic aerothermodynamics CFD solver to evaluate the effect of spalled particles on the flow field. Time accurate solutions are computed in argon and air flow fields. A single particle simulations and multiple particles simulations are performed and studied. The results show that the carbon vapor released by spalled particles tend to change the composition of the flow field, particularly the upstream region of the shock.

High-Temperature, High-Pressure Viscosities And Densities Of Toluene, Aaron J. Rowane

Theses and Dissertations

High-temperature, high-pressure (HTHP) conditions are exemplified in ultra-deep petroleum reservoirs and can be exhibited within diesel engines. Accurate pure component hydrocarbon data is essential in understanding the overall behavior of petroleum and diesel fuel at these conditions. The present study focuses on the HTHP properties of toluene since this hydrocarbon is frequently used to increase the octane rating of gasoline and toluene occurs naturally in crude oil. In this thesis experimental densities and viscosity are presented to 535 K and 300 MPa extending the database of toluene viscosity data to higher temperature than previous studies. The data is correlated to …

A Soft Condensed Matter Approach Towards Mathematical Modelling Of Mass Transport And Swelling In Food Grains, Michael Chapwanya, N. Misra

Articles

Soft condensed matter (SCM) physics has recently gained importance for a large class of engineering materials. The treatment of food materials from a soft matter perspective, however, is only at the surface and is gaining importance for understanding the complex phenomena and structure of foods. In this work, we present a theoretical treatment of navy beans from a SCM perspective to describe the hydration kinetics. We solve the transport equations within a porous matrix and employ the Flory–Huggin’s equation for polymer–solvent mixture to balance the osmotic pressure. The swelling of the legume seed is modelled as a moving boundary with …

Thermodynamically Coupled Heat And Mass Flows In A Reaction-Transport System With External Resistances, Yaşar Demirel

Yaşar Demirel Publications

Considerable work has been published on mathematically coupled nonlinear differential equations by neglecting thermodynamic coupling between heat and mass flows in reaction-transport systems. The thermodynamic coupling refers that a flow occurs without or against its primary thermodynamic driving force, which may be a gradient of temperature, or chemical potential, or reaction affinity. This study presents the modeling of thermodynamically coupled heat and mass flows of two components in a reaction-transport system with external heat and mass transfer resistances. The modeling equations are based on the linear nonequilibrium thermodynamics approach by assuming that the system is in the vicinity of global …

Modeling Of Thermodynamically Coupled Reaction-Transport Systems, Yaşar Demirel

Yaşar Demirel Publications

Nonisothermal reaction-diffusion systems control the behavior of many transport and rate processes in physical, chemical and biological systems, such as pattern formation and chemical pumps. Considerable work has been published on mathematically coupled nonlinear differential equations by neglecting thermodynamic coupling between a chemical reaction and transport processes of mass and heat. This study presents the modeling of thermodynamically coupled system of a simple elementary chemical reaction with molecular heat and mass transport. The thermodynamic coupling refers that a flow occurs without or against its primary thermodynamic driving force, which may be a gradient of temperature or chemical potential or reaction …

Stability Of Transport And Rate Processes [Review], Yaşar Demirel

Papers in Thermal Mechanics

About fifty years ago, the Turing instability demonstrated that even simple reaction-diffusion systems might lead to spatial order and differentiation, while the Rayleigh-Bénard instability showed that the maintenance of nonequilibrium might be the source of order in fluids subjected to a thermodynamic force above a critical value. Therefore, distance from global equilibrium in the form of magnitude of a thermodynamic force emerges as another constraint of stability; some systems may enhance perturbations, and evolve to highly organized states called the dissipative structures after a critical distance on the thermodynamic branch. Although the kinetics and transport coefficients represent short-range interactions, chemical …

Design And Simulation Of An Induction Skull Melting System, Taide Tan

UNLV Theses, Dissertations, Professional Papers, and Capstones

Incorporating volatile actinides, mainly americium into a metallic fuel pin (MFP) has been a serious problem due to americium’s high vapor pressure. An Induction Skull Melting (ISM) system was identified by Argonne National Laboratory (ANL) as a potential furnace design to cast MFPs. Through the development of the ISM system, the nuclear waste feedstock can be melted and injected into the mold for fabricating MFPs in the advanced nuclear fuel cycles. The main phenomena in this system include: induction melting process, casting process and mass transfer process of americium. Issues related to ISM system design for casting MFPs are discussed …

Gibbs Dividing Surface And Helium Adsorption, Sasidhar Gumma, Orhan Talu

Chemical & Biomedical Engineering Faculty Publications

All adsorption data is based on the definition of Gibbs dividing surface, which is a purely mathematical transformation. Adsorption measurements in microporous solids necessitate experimental determination of the dividing surface. An international protocol does not exist on how to perform this important measurement. Commonly, helium is assumed not to adsorb and used as a probe molecule for this measurement. Each experimentalist chooses an arbitrary set of conditions, often without even disclosing them, which adds to the confusion in adsorption literature. Here, a self-consistent method for the analysis of helium data is proposed which does not assume non-adsorbing helium …

Molecular Simulation Of Adsorption: Gibbs Dividing Surface And Comparison With Experiment, Orhan Talu, Alan L. Myers

Chemical & Biomedical Engineering Faculty Publications

At low temperature near the normal boiling point, computer simulations of adsorption of gases can be compared directly with experiment. However, for adsorptive gas separations in which the gas is adsorbed near or above its critical temperature, absolute simulation variables must be converted to excess variables for comparison with experiment. The conversion of absolute to excess variables requires the helium pore volume of the adsorbent. Lennard-Jones potential parameters for helium gas molecules interacting with the oxygen atoms of silicalite are ε/k = 28.0 K and σ = 2.952 Å. The helium pore volume of silicalite is 0.175 cm …

Effects Of Concentration And Temperature On The Coupled Heat And Mass Transport In Liquid Mixtures, Yaşar Demirel, Stanley I. Sandler

Papers in Thermal Mechanics

Using published experimental data on the thermal conductivity, mutual diffusivity, and heats of transport, the degree of coupling between heat and mass flows has been calculated for binary and ternary nonideal liquid mixtures. The binary mixtures consist of two types: the first is six systems of six-to-eight-carbon straight and branched chain alkanes in chloroform and in carbon tetrachloride; and the second is mixtures of carbon tetrachloride with benzene, toluene, 2-propanone, n-hexane, and 11-octane. The ternary mixture considered is toluene-chlorobenzene-bromobenzene. The published data are available at 35°C, 30°C, and 35°C and ambient pressure. Using the linear nonequilibi-ium thermodynainics (LNET) and the …

Editorial, Orhan Talu, Shivaji Sircar

Chemical & Biomedical Engineering Faculty Publications

No abstract provided.

Droplet Evaporation And Deformations In An Amplitude Modulated Ultrasonic Field, Nihad E. Daidzic, Rene Stadler, Adrian Melling

Aviation Department Publications

The aim of the report presented is the measurements of droplet oscillations.

A New Spray Evaporation Model Based On Droplet Interface Phenomena, Nihad E. Daidzic, Gangolf Kohnen, Martin Sommerfeld

Aviation Department Publications

In this work the influence of droplet shape oscillations on droplet evaporation is shown. Through nonlinear mode interactions, turbulence and aerodynamic triggering of vibrations cause by vortex shedding, droplets always oscillates in spray flows. Droplet shape oscillation cause higher evaporation rates through several physical phenomena such as an average increase of the superficial surface area, periodic micro-convection and boundary layer destruction, and local saturation pressure changes due to local curvature effects. The inviscid theory of small-amplitude droplet oscillations was used which resulted in better agreement with the measurement data of droplet size distributions in sprays for different axial coordinates.

Electrostatic Positioning Of Droplets In Turbulent Flows (Lstm 375/Te/93), Nihad E. Daidzic, Adrian Melling

Aviation Department Publications

Report LSTM 375/TE/93, Lehrstuhl fuer Stroemungsmechanik Universitaet Erlangen-Nuernberg Cauerstr. 4, 8520 Erlangen Germany.

A Mathematical Model And Simulation Of Natural Circulation Loop Thermalhydraulics, Nihad E. Daidzic

Aviation Department Publications

In this work, a simple, nonlinear, seventh-order mathematical model with lumped parameter analysis of the thermalhydraulic processes in a natural circulation steam boiler loop is presented. Digital simulation has been performed in order to predict open loop transients in severe accidental situations. Parts of the circulation loop such as the steam drum, downcomer, and riser were modelled separately on the basis of the integral balance equations. The two-phase flow in the steam drum and in the riser was modelled with the aid of a homogeneous-equilibrium, two-phase flow model. Special care was taken to ensure the stability of the numerical scheme, …