Mechanical Engineering Commons^™

Evaluating Electrification Of Fossil Fuel-Fired Boilers For Decarbonization Using Discrete Event Simulation, Nahian Ismail Chowdhury

Graduate Theses, Dissertations, and Problem Reports

Decarbonizing fossil fuel usage is crucial in mitigating the impacts of climate change. CO2, which comprises the major portion of greenhouse gas, is emitted from burning fossil fuels. One of the significant sources of fossil fuel user is industrial process heating, and most of the heating in industrial processes is achieved through boilers. Electrification is a promising solution for decarbonizing these boilers, as it enables renewable energy sources to generate electricity, which can then be used to power the electric boilers. The electrification of boilers can reduce greenhouse gas emissions, improve air quality, and increase energy efficiency. However, it requires …

The Optimization Of Failure Risk Estimation On The Uniform Corrosion Rate With A Non-Linear Function, Fernanda Hartoyo, Jaka Fajar Fatriansyah, Imam Abdillah Mas'ud, Farhan Rama Digita, Hanna Ovelia, Datu Rizal Asral

Journal of Materials Exploration and Findings

Failures in the oil and gas pipeline system are conditions that must be avoided and anticipated because the losses due to the failures can occur at a very high level. Internal corrosion is one of the significant causes of the failures in pipeline systems. In addition, this type of corrosion is due to the high content of carbon dioxide and other corrosive substances in crude oil and natural gas. Therefore, an optimal inspection scheduling system is required to prevent the possibility of pipeline failures due to corrosion and to avoid any overspending on the budget due to excessive inspection scheduling. …

Pore Microstructure Impacts On Lithium Ion Transport And Rate Capability Of Thick Sintered Electrodes, Ziyang Nie, Rohan Parai, Chen Cai, Charles Michaelis, Jacob M. Lamanna, Daniel S. Hussey, David L. Jacobson, Dipankar Ghosh, Gary M. Koenig Jr.

Mechanical & Aerospace Engineering Faculty Publications

Increasing electrode thickness is one route to improve the energy density of lithium-ion battery cells. However, restricted Li⁺ transport in the electrolyte phase through the porous microstructure of thick electrodes limits the ability to achieve high current densities and rates of charge/discharge with these high energy cells. In this work, processing routes to mitigate transport restrictions were pursued. The electrodes used were comprised of only active material sintered together into a porous pellet. For one of the electrodes, comparisons were done between using ice-templating to provide directional porosity and using sacrificial particles during processing to match the geometric density …

Cfd Modeling Of Smoke Movement In An Atrium, Robin Wu

UNLV Theses, Dissertations, Professional Papers, and Capstones

The purpose of this paper is to better understand the behavior of smoke movement in an atrium. Thus gives first responders and civilians in and out of building a better understanding

With the advancements of modern technology, computers and softwares make simulation models possible such as fire models to simulate fire and smoke movements. In this paper, a computational fluid dynamic (CFD) software Fire Dynamic Simulator (FDS) is used to conduct a series of atrium tests to investigate the effectiveness of smoke exhaust systems. FDS solves the Navier-Stokes equations appropriate for low speed flows (Ma < 0.3) with an emphasis on smoke, heat transport and CO2 concentrations from fires. The default turbulence model used in FDS simulation is the Large Eddy Simulation (LES), which is the solution of Navier-Stokes equations at low speed.

The compartment tested was 9 …

Thermophotovoltaic Devices: Combustion Chamber Optimization And Modelling To Maximize Fuel Efficiency, Arnold Chris Toppo, Ernesto Marinero, Zhaxylyk Kudyshev

The Summer Undergraduate Research Fellowship (SURF) Symposium

Currently, 110 billion cubic meters of natural gas (primarily methane), a potent greenhouse gas, are flared off for environmental and safety reasons. This process results in enough fuel to provide the combined natural gas consumption of Germany and France. The research team developed a thermophotovoltaic device to convert thermal energy to electricity at a high efficiency using proprietary emitters and combustion system. With the current focus being fuel efficiency and the combustion process, the assembly was simulated using ANSYS Fluent modelling software and the following parameters were optimized: air/fuel ratios, flow rates, and inlet sizes. Simultaneously the heat transfer across …

Aspen Plus Simulation Of Biomass Gasification In A Steam Blown Dual Fluidised Bed, Wayne Doherty, Anthony Reynolds, David Kennedy

Book/Book Chapters

The efficient utilisation of biomass resources is of utmost importance. Biomass gasification offers much higher efficiencies than combustion. Gasification is a process in which a fuel is converted to a combustible gas (syngas). A dual fluidised bed gasifier known as the fast internally circulating fluidised bed (FICFB) was selected. It has been demonstrated at industrial scale and data is readily available for model validation. An Aspen Plus model was developed to simulate the FICFB gasifier. The model is based on Gibbs free energy minimisation and the restricted equilibrium method was used to calibrate it. The model has been validated and …

Optimization Of Mixing In A Simulated Biomass Bed Reactor With A Center Feeding Tube, Michael T. Blatnik

Masters Theses 1911 - February 2014

Producing gasoline-type fuels from lignocellulosic biomass has two advantages over producing alcohol-type fuels from plant sugars: gasoline has superior fuel characteristics and plant lignin/cellulose does not compete with human food supplies. A promising technology for converting lignocellulose to fuel is catalytic fast pyrolysis (CFP). The process involves injecting finely ground biomass into a fluidized bed reactor (FBR) at high temperatures, which reduce the biomass to gases that react inside the catalyst particles. This entails complex hydrodynamics to efficiently mix a stream of biomass into a catalyst bed that is fluidized by a separate stream of inert gas. Understanding the hydrodynamics …

Using Thermally Coupled Reactive Distillation Columns In Biodiesel Production, Nghi Nguyen, Yaşar Demirel

Yaşar Demirel Publications

Production of ethyl dodecanoate (biodiesel) using lauric acid and methanol with a solid acid catalyst of sulfated zirconia is studied by using two distillation sequences. In the first sequence, the methanol recovery column follows the reactive distillation column. In the second sequence, the reactive distillation and methanol recovery columns are thermally coupled. Thermally coupled distillation sequences may consume less energy by allowing interconnecting vapor and liquid streams between the two columns to elminate reboiler or condenser or both. Here we study the thermally coupled side-stripper reactive distillation and eliminate the condenser of the reactive distillation column. Both the sequences are …

Simulation Of A Tubular Solid Oxide Fuel Cell Stack Operating On Biomass Syngas Using Aspen Plus, Wayne Doherty, Anthony Reynolds, David Kennedy

Articles

A tubular solid oxide fuel cell (SOFC) stack was modelled and its operation on biomass syn-gas was investigated. The objective of this work was to develop a computer simulation model of a biomass gasification-SOFC (BG-SOFC) system capable of predicting performance under various operating conditions and using diverse fuels. The stack was modelled using Aspen Plus and considers ohmic, activation and concentration losses. It was validated against published data for operation on natural gas. Operating parameters such as fuel and air utilisation factor U_f and U_a, current density j and steam to carbon ratio STCR were varied and …

Simulation Of A Tubular Solid Oxide Fuel Cell Stack Operating On Biomass Syn-Gas Using Aspen Plus, Wayne Doherty, Anthony Reynolds, David Kennedy

Articles

A tubular solid oxide fuel cell (SOFC) stack is modelled and its operation on biomass syn-gas is investigated. The objective of this work is to develop a computer simulation model of a biomass gasification-SOFC (BG-SOFC) system capable of predicting performance under various operating conditions and using diverse fuels. The stack is modelled using Aspen Plus and considers ohmic, activation and concentration losses. It is validated against published data for operation on natural gas. Operating parameters such as fuel and air utilisation factor (U_f and U_a), current density (j) and steam to carbon ratio ( …

Simulation Of A Circulating Fluidised Bed Biomass Gasifier Using Aspen Plus: A Performance Analysis, Wayne Doherty, Anthony Reynolds, David Kennedy

Conference Papers

In the near future biomass gasification is likely to play an important role in energy production and conversion. Its application has great potential in the context of climate change mitigation, increasing efficiency and energy security. Atmospheric circulating fluidised bed (CFB) technology was selected for the current study. An original computer simulation model of a CFB biomass gasifier was developed using ASPEN Plus (Advanced System for Process ENgineering Plus). It is based on Gibbs free energy minimisation and the restricted equilibrium method was used to calibrate it against experimental data. This was achieved by specifying the temperature approach for the gasification …

Analysis Of Technical Energy Losses By Using Simulation, Betrianis Betrianis, Randite Herawan

Makara Journal of Technology

Model is a representation of a system. Through model, it can be easier to forecast and control the changing of each element system. Electricity distribution is also a system. Losses are general problem that exist in a distribution network system. But with the right methods, specifically technical energy losses can be reduced in order to increase the efficiency. By making model of the distribution network, the value of technical energy losses in the whole network as well as in every line can be observed. Simulation can also be used to see all losses reduction alternatives. By comparing results from each …

A Finite Element Simulation Of Temperature And Material Flow In Fricton Stir Welding, Mark J. Lasley

Theses and Dissertations

The purpose of this research was to use the Transvalor S.A. product, Forge3, to develop a finite element simulation of the friction stir welding process that improves the predictability of temperature evolution and material flow within the plunge portion of the process. Previous modeling created more heating within the billet than experimental results, probably due to the simplification of the simulation with adiabatic boundary conditions. More realistic tooling temperatures were included in this model as these affect heat evolution which is a determining factor in microcrystalline growth. These results were validated by experimental efforts using a billet and tooling instrumented …

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, …