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Full-Text Articles in Engineering
Dry Reforming Of Methane Using Microwave Irradiated Metal Oxide/Coal Char Catalysts, Anthony Carter
Dry Reforming Of Methane Using Microwave Irradiated Metal Oxide/Coal Char Catalysts, Anthony Carter
Graduate Theses, Dissertations, and Problem Reports
This research focuses on the synthesis of both shaped and amorphous powder materials, the combination of these materials with dried Powder River Basin (PRB) coal char, and their reactionary properties with methane and carbon dioxide gasses with conventional and microwave (MW) heating. The first goal of this project was to synthesize shaped micro and nano sized particles with ideal dielectric properties for converting electromagnetic energy into heat and proven capabilities of activating methane. These particles were synthesized via solvothermal, hydrothermal, and co-preceptory treatments alone and onto the surface of dried PRB coal char. PRB is a sub-bituminous, low-ranking coal (LRC) …
An Analytical Model To Predict The Length Of Oxygen-Assisted, Swirled, Coal And Biomass Flames, David Arthur Ashworth
An Analytical Model To Predict The Length Of Oxygen-Assisted, Swirled, Coal And Biomass Flames, David Arthur Ashworth
Theses and Dissertations
Government regulations to reduce pollutants and increasing environmental awareness in the power generation industry have encouraged coal power plants to begin firing biomass in their boilers. Biomass generally consists of larger particles which produce longer flames than coal for a given burner. The length of the flame is important in fixed-volume boilers because of its influence on heat transfer, corrosion, deposition, and pollutant formation. Many pulverized fuel burners employ a series of co-annular tubes with various flows of fuel and air to produce a stabilized flame. A variable swirl burner with three co-annular tubes, each of variable diameter, has been …
Effects Of Biomass Moisture Content On Volatile Flame Length During Cofiring With Coal, Matthew Pollard
Effects Of Biomass Moisture Content On Volatile Flame Length During Cofiring With Coal, Matthew Pollard
McKelvey School of Engineering Theses & Dissertations
Cofiring biomass with coal can contribute to meeting Renewable Portfolio Standards (RPS) and reduce pollutant emissions. The physical characteristics and composition of biomass can vary significantly, which can affect the combustion characteristics. When cofiring biomass with coal, these differences can impact the structure of the volatile flame, the region where combustion of volatiles dominates. The length and location of the volatile flame is important to flame stability and determines the location and extent of volatile release. This has an effect on pollutant emissions, such as NOx (nitrogen oxides). Previously, the effects of parameters such as cofiring ratio, particle size, and …
The Composition And Morphology Of Coal Ash Deposits Collected In An Oxy-Fuel, Pulverized Coal Reactor, Curtis K. Stimpson
The Composition And Morphology Of Coal Ash Deposits Collected In An Oxy-Fuel, Pulverized Coal Reactor, Curtis K. Stimpson
Theses and Dissertations
Coal ash deposits were collected in a 160 kWth, down-fired oxy-coal reactor under staged and unstaged conditions for four different coals (PRB, Gatling, Illinois #6, and Mahoning). Concentration measurements of carbon, oxygen, sodium, magnesium, aluminum, silicon, phosphorus, sulfur, chlorine, potassium, calcium, titanium, chromium, manganese, iron, nickel, strontium, and barium were gathered from each deposit sample using scanning electron microscopy and energy dispersive spectroscopy (SEM-EDS). Backscattered electron micrographs for each deposit sample were analyzed to gather morphological data. Particle size and shape were studied for each deposit collected. The average particle sizes of the particles in upstream deposits were much larger …
The Composition And Distribution Of Coal-Ash Deposits Under Reducing And Oxidizing Conditions From A Suite Of Eight Coals, David R. Brunner
The Composition And Distribution Of Coal-Ash Deposits Under Reducing And Oxidizing Conditions From A Suite Of Eight Coals, David R. Brunner
Theses and Dissertations
Eighteen elements, including: carbon, oxygen, sodium, magnesium, aluminum, silicon, phosphorus, sulfur, chlorine, potassium, calcium, titanium, chromium, manganese, iron, nickel, strontium, and barium were measured using a scanning electron microscope with energy dispersive spectroscopy from deposits. The deposits were collected by burning eight different coals in a 160 kWth, staged, down-fired, swirl-stabilized combustor. Both up-stream and down-stream deposits from an oxidizing region (equivalence ratio 0.86) and reducing region (equivalence ratio 1.15) were collected. Within the deposits, the particle size and morphology were studied. The average particle cross-sectional area from the up-stream deposits ranged from 10 - 75 µm2 and had a …
Corrosion-Related Gas Measurements And Analysis For A Suite Of Coals In Staged Pulverized Coal Combustion, Todd A. Reeder
Corrosion-Related Gas Measurements And Analysis For A Suite Of Coals In Staged Pulverized Coal Combustion, Todd A. Reeder
Theses and Dissertations
Eleven gas species, including CO, CO2, H2, H2O, H2S, HCl, NOX, O2, SO2, COS and SO3, were measured in a 150 kWth, staged, pulverized coal, down-fired combustor using a Fourier transform infrared (FTIR) spectrometer, gas chromatograph (GC), and a Horiba PG-250 5-gas analyzer. Additional gases such as HCN, NH3, CH4, and other hydrocarbons were also measured. Seven coals of varying rank and composition were investigated. Measurements were obtained in reducing (S.R. = 0.85) and oxidizing (S.R. = 1.15) conditions. In particular, sulfur- and chlorine-containing species including H2S, SO2, COS, SO3, and HCl are discussed. In the reducing zone, all four …
A Method For Making In Situ Emittance Measurements Of Coal Ash Deposits, Travis J. Moore
A Method For Making In Situ Emittance Measurements Of Coal Ash Deposits, Travis J. Moore
Theses and Dissertations
A major problem associated with any power generation process in which coal is burned is the formation of ash and slag from the inorganic constituents of the coal. Ash deposition on heat transfer surfaces in coal-fired reactors is unavoidable and can have a significant effect on the performance and maintenance of boilers and gasifiers. A greater understanding of the thermal properties of coal ash deposits is important in reducing their negative impact. This work presents the development of an experimental method for making in situ measurements of the spectral emittance of coal ash deposits. It also provides measured emittances for …
Characterization Of The Thermal Transport Through A Temporally-Varying Ash Layer, Darron Palmer Cundick
Characterization Of The Thermal Transport Through A Temporally-Varying Ash Layer, Darron Palmer Cundick
Theses and Dissertations
Ash deposits in commercial coal-fired boilers frequently pose serious maintenance challenges and decrease thermal efficiency. A better understanding of fundamental thermal transport properties in ash deposits can help mitigate their negative effects. In order to characterize the thermal properties of boiler-side deposits, this work presents a thermal transport model and in-situ measurements of effective thermal conductivity in coal ash deposits. A simple model of the thermal transport through an ash deposit, with and with out slagging, was developed. The model approximates the deposit by dividing it into four regimes: particulate, sintered, solidified slag, and molten slag. The development of this …
A Mechanistic Investigation Of Nitrogen Evolution In Pulverized Coal Oxy-Fuel Combustion, Andrew John Mackrory
A Mechanistic Investigation Of Nitrogen Evolution In Pulverized Coal Oxy-Fuel Combustion, Andrew John Mackrory
Theses and Dissertations
Oxy-fuel combustion is an enabling technology for capture of CO2 from coal combustion, the economics of which depends strongly on the ability of the process to produce low NOX emissions. The literature contains many reports of lower NOX emissions from oxy-fuel combustion but the reasons for this are not fully understood. The objective of this work was to gain understanding of nitrogen evolution under pulverized coal oxy-fuel conditions. Pulverized coal was burned in a once-through, down-fired, laminar flow reactor. Nitrogen compounds and other combustion species were measured at the reactor centerline as a function of distance from the burner. Dry …
Measurements And Modeling Of Coal Ash Deposition In An Entrained-Flow Reactor, Ryan P. Blanchard
Measurements And Modeling Of Coal Ash Deposition In An Entrained-Flow Reactor, Ryan P. Blanchard
Theses and Dissertations
Coal plays a significant role in meeting the world's need for energy and will continue to do so for many years to come. Economic, environmental, and public opinion are requiring coal derived energy to be cleaner and operate in a more narrow window of operating conditions. Fouling and slagging of heat transfer surfaces continues to be a challenge for maintaining boiler availability and expanding the use of available fuels and operating conditions. The work incorporates existing information in the literature on ash deposition into a User-Defined Function (UDF) for a commercial comprehensive combustion and CFD code. Results from the new …