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Full-Text Articles in Engineering
A Review Of Coal Heating Value Correlations With Application To Coal Char, Tar, And Other Fuels, Andrew P. Richards, Denver Haycock, Jacob F. Frandsen, Thomas H. Fletcher
A Review Of Coal Heating Value Correlations With Application To Coal Char, Tar, And Other Fuels, Andrew P. Richards, Denver Haycock, Jacob F. Frandsen, Thomas H. Fletcher
Faculty Publications
Accurately measuring a fuel’s heating value is one of the first steps in the classification of a new fuel. Heating values are widely used in coal combustion research and are becoming more useful in other fuel types as well. Many different empirical correlations to predict heating values based on primary organic (CHONS) elemental composition are found in the literature, many of which were originally created to predict heating values of parent coal, and some of which have been extended for biomass. However, no correlations exist for heating values of coal chars and tars. Thirteen literature heating value correlations (10 model …
Heating Rate And Temperature Effects On Pyrolysis Products From Live Wildland Fuels, Mohammad-Saeed Safdari, Elham Amini, David R. Weise, Thomas H. Fletcher
Heating Rate And Temperature Effects On Pyrolysis Products From Live Wildland Fuels, Mohammad-Saeed Safdari, Elham Amini, David R. Weise, Thomas H. Fletcher
Faculty Publications
Wildland fire, which includes both planned (prescribed fire) and unplanned (wildfire) fires, is an important component of many ecosystems. During wildland fires, low heating rate pyrolysis (slow pyrolysis) occurs during preheating and/or smoldering of plant material. High heating rate pyrolysis (fast pyrolysis) exists in the flame region. Pyrolysis temperature and heating rate play important roles on the yields and the compositions of pyrolysis products. In this work, the effects of pyrolysis temperature and heating rate on the yields and the compositions of pyrolysis products from 14 plant species native to the forests of the southern United States are shown. The …
Pyrolysis Kinetics Of Live And Dead Wildland Vegetation From The Southern United States, Elham Amini, Mohammad-Saeed Safdari, David R. Weise, Thomas H. Fletcher
Pyrolysis Kinetics Of Live And Dead Wildland Vegetation From The Southern United States, Elham Amini, Mohammad-Saeed Safdari, David R. Weise, Thomas H. Fletcher
Faculty Publications
The fundamental combustion behavior of live wildland vegetation is not fully understood. Since the combustion process during wildland fire starts with pyrolysis, there is a need for better understanding of pyrolysis to develop improved wildland fire models. The kinetics of pyrolysis of live and dead wildland vegetation has not been explored in detail. In this study, the pyrolysis kinetics were determined for 14 different plant species (live and dead) which are all native to the forests in the southern United States. Pyrolysis experiments were carried out in a Thermogravimetric analyzer (TGA) under inert conditions at 5 different heating rates ranged …
Characterization Of Pyrolysis Products From Fast Pyrolysis Of Live And Dead Vegetation, Mohammad Saeed Safdari
Characterization Of Pyrolysis Products From Fast Pyrolysis Of Live And Dead Vegetation, Mohammad Saeed Safdari
Theses and Dissertations
Wildland fire, which includes both planned (prescribed fire) and unplanned (wildfire) fires, is an important component of many ecosystems. Prescribed burning (controlled burning) is used as an effective tool in managing a variety of ecosystems in the United States to reduce accumulation of hazardous fuels, manage wildlife habitats, mimic natural fire occurrence, manage traditional native foods, and provide other ecological and societal benefits. During wildland fires, both live and dead (biomass) plants undergo a two-step thermal degradation process (pyrolysis and combustion) when exposed to high temperatures. Pyrolysis is the thermal decomposition of organic material, which does not require the presence …
Modeling Soot Formation Derived From Solid Fuels, Alexander Jon Josephson
Modeling Soot Formation Derived From Solid Fuels, Alexander Jon Josephson
Theses and Dissertations
Soot formation from complex solid fuels, such as coal or biomass, is an under-studied and little understood phenomena which has profound physical effects. Any time a solid fuel is combusted, from coal-burning power plants to wildland fires, soot formation within the flame can have a significant influence on combustion characteristics such as temperature, heat flux, and chemical profiles. If emitted from the flame, soot particles have long-last effects on human health and the environment. The work in this dissertation focuses on creating and implementing computational models to be used for predicting soot mechanisms in a combustion environment. Three models are …
Thermochemical Conversion Of Biomass: Detailed Gasification And Near-Burner Co-Firing Measurements, Jacob B. Beutler
Thermochemical Conversion Of Biomass: Detailed Gasification And Near-Burner Co-Firing Measurements, Jacob B. Beutler
Theses and Dissertations
An increasing emphasis on mitigating global climate change (global warming) over the last few decades has created interest in a broad range of sustainable or alternative energy systems to replace fossil fuel combustion. Biomass, when harvested responsibly, is a renewable fuel with many uses in replacing fossil fuels. Cofiring biomass with coal in traditional large-scale coal power plants represents one of the lowest risk, least costly, near-term methods of CO2 mitigation. Simultaneously, it is one of the most efficient and inexpensive uses of biomass. Alternatively, biomass can be transformed into useful products through gasification to produce clean syngas for …
Characterization Of Pyrolysis Products From Fast Pyrolysis Of Live And Dead Vegetation Native To The Southern United States, Mohammad-Saeed Safdari, Mahmood Rahmati, Elham Amini, Joel E. Howarth, Jansen P. Berryhill, Mark Dietenberger, David R. Weise, Thomas H. Fletcher
Characterization Of Pyrolysis Products From Fast Pyrolysis Of Live And Dead Vegetation Native To The Southern United States, Mohammad-Saeed Safdari, Mahmood Rahmati, Elham Amini, Joel E. Howarth, Jansen P. Berryhill, Mark Dietenberger, David R. Weise, Thomas H. Fletcher
Faculty Publications
Prescribed burning (controlled burning) is used to decrease accumulation of combustible materials and reduce impact of uncontrolled wildland fires. Prescribed fires are often used to burn undergrowth in Southern forests of the United States. In order to improve prescribed fire application, accomplish desired fire effects, and limit potential runaway fires, an improved understanding of the fundamental processes related to combustion of heterogeneous fuel beds of live and dead fuels is needed. The initial processes of combustion involve pyrolysis and ignition. During this research, fast pyrolysis of 14 live and dead (biomass) plant species which are native to the Southern United …
Gasification Of Biomass, Coal, And Petroleum Coke At High Heating Rates And Elevated Pressure, Aaron D. Lewis
Gasification Of Biomass, Coal, And Petroleum Coke At High Heating Rates And Elevated Pressure, Aaron D. Lewis
Theses and Dissertations
Gasification is a process used to convert any carbonaceous species through heterogeneous reaction to obtain the desired gaseous products of H2 and CO which are used to make chemicals, liquid transportation fuels, and power. Both pyrolysis and heterogeneous gasification occur in commercial entrained-flow gasifiers at pressures from 4 to 65 atm with local gas temperatures as high as 2000 °C. Many gasification studies have been performed at moderate temperatures, heating rates, and pressures. In this work, both pyrolysis and char gasification experiments were performed on coal, petroleum coke, and biomass at conditions pertinent to commercial entrained-flow gasifiers. Rapid biomass pyrolysis …
Co2 Char Gasification Rates Of Sawdust, Switchgrass, And Corn Stover In A Pressurized Entrained-Flow Reactor, Thomas H. Fletcher, Aaron D. Lewis, Emmett G. Fletcher
Co2 Char Gasification Rates Of Sawdust, Switchgrass, And Corn Stover In A Pressurized Entrained-Flow Reactor, Thomas H. Fletcher, Aaron D. Lewis, Emmett G. Fletcher
Faculty Publications
An entrained-flow flat-flame burner reactor was used to measure apparent CO2 gasification rates of near-spherical biomass chars of poplar sawdust, switchgrass, and corn stover using particle residence times1258−1891 K and 6.1− 13.5 atm, respectively. A new method was developed to produce near-spherical particles from nonspherical biomass chars. The apparent CO2 gasification rates for the three biomass chars with mean diameters near 100 μm were fit to a global first-order model, and the optimal kinetic parameters are reported. The measured gasification rate of poplar sawdust was about 3.9 times faster than that of switchgrass char, but only about 20% faster than …
Application Of One Dimensional Turbulence (Odt) To Model Fire Spread Through Biomass Fuel Bed, Abinash Paudel
Application Of One Dimensional Turbulence (Odt) To Model Fire Spread Through Biomass Fuel Bed, Abinash Paudel
Theses and Dissertations
Each year fires destroy millions of acres of woodland, lives, and property, and significantly contribute to air pollution. Increased knowledge of the physics and properties of the flame propagation is necessary to broaden the fundamental understanding and modeling capabilities of fires. Modeling flame propagation in fires is challenging because of the various modes of heat transfer with diverse fuels, multi-scale turbulence, and complex chemical kinetics. Standard physical models of turbulence like RANS and LES have been used to understand the flame behavior, but these models are limited by computational cost and their inability to resolve sub-grid scales. Application of several …
Prediction Of Tar And Light Gas During Pyrolysis Of Black Liquor And Biomass, Thomas H. Fletcher, Harland R. Pond, Jarom Webster, Judson Wooters, Larry L. Baxter
Prediction Of Tar And Light Gas During Pyrolysis Of Black Liquor And Biomass, Thomas H. Fletcher, Harland R. Pond, Jarom Webster, Judson Wooters, Larry L. Baxter
Faculty Publications
A generalized model for describing the pyrolysis behavior of low-grade fuels is being developed for incorporation into larger combustion simulation models. Light gas and tar yields from black liquor or biomass pyrolysis can be predicted using the chemical percolation devolatilization (CPD) model originally developed for coal. The initial approach is to measure the average chemical structures in a black liquor sample using 13C NMR spectroscopy. These chemical structures are then used in pyrolysis model predictions. With few changes from the coal-derived kinetic parameters, the model describes the organic pyrolysis behavior of black liquor samples obtained in a nitrogen-purged furnace. It …
Mechanistic Investigation Of Ash Deposition In Pulverized-Coal And Biomass Combustion, Shrinivas Sadashiv Lokare
Mechanistic Investigation Of Ash Deposition In Pulverized-Coal And Biomass Combustion, Shrinivas Sadashiv Lokare
Theses and Dissertations
This investigation details the effects of fuel constituents on ash deposition through systematic experimental and theoretical analyses of fundamental particle experiments and a suite of fuels with widely varying inorganic contents and compositions. The experiments were carried out in the Multifuel Flow Reactor (MFR) at Brigham Young University. Fuels included several biomass fuels (straw, sawdust and mixtures of straw-sawdust with other additives such as Al(OH)3, CaCO3, etc.) and four commercially-used coals (Illinois#6, Powder River Basin – Caballo and Cordero, Blind Canyon, and Lignite – Beulah Zap). The data from the series of experiments quantitatively illustrate the effects of fuel properties, …
Experimental And Modeling Investigations Of Biomass Particle Combustion, Hong Lu
Experimental And Modeling Investigations Of Biomass Particle Combustion, Hong Lu
Theses and Dissertations
This investigation provides a comprehensive analysis of entrained-flow biomass combustion processes. Experimental and theoretical investigations indicate how particle shape and size influence biomass combustion rates. Experimental samples include flake-like, cylinder-like, and equant (nearly spherical) shapes with similar particle masses and volumes but different surface areas. Samples of small (less than 500 µm) particles were passed through a laboratory entrained-flow reactor in a nitrogen/air atmosphere and a maximum reactor wall temperature of 1600 K, while large samples were reacted in suspension in a single particle furnace operated at similar conditions as the entrained-flow reactor. A separately developed computer and image analysis …
Fuel-Nox Formation During Low-Grade Fuel Combustion In A Swirling-Flow Burner, Chunyang Wu
Fuel-Nox Formation During Low-Grade Fuel Combustion In A Swirling-Flow Burner, Chunyang Wu
Theses and Dissertations
Insufficient knowledge of fireside behavior in the near-burner region during biomass combustion is one of major factors preventing widespread use of this renewable fuel in pulverized coal power plants. The current research is aimed to investigate the impact of biomass cofiring on NO formation in the near-burner region through interpretation of computational fluid dynamics (CFD) predictions and data collected from a series of biomass tests in a pilot-scale (0.2 MW), swirling flow burner. Two-dimensional gas species mole fraction data were collected with state-of-theart instruments from nine experiments, composing one herbaceous biomass (straw), one woody biomass (sawdust), a low sulfur sub-bituminous …
Analysis Of Grain Screenings By X-Ray Photoelectron Spectroscopy, Guilin Jiang, Ghaleb A. Husseini, Larry Lin Baxter, Matthew R. Linford
Analysis Of Grain Screenings By X-Ray Photoelectron Spectroscopy, Guilin Jiang, Ghaleb A. Husseini, Larry Lin Baxter, Matthew R. Linford
Faculty Publications
Determining the chemical structure and composition of biomass fuels using x-ray photoelectron spectroscopy XPS can provide fundamental knowledge of their structures that is useful in understanding and predicting their combustion behavior. Grain screenings are an example of an agricultural residue byproduct of food and feed production of potential interest for biomass combustion. The XPS spectra of grain screenings provide both its elemental composition and indications of its bonding. Traditional fuel analyses of this fuel are also provided. These include: ultimate analysis — the elemental composition of the overall fuel C, H, N, S, and O; chlorine analysis — reported here …
Analysis Of Sawdust By X-Ray Photoelectron Spectroscopy, Guilin Jiang, Ghaleb A. Husseini, Larry Lin Baxter, Matthew R. Linford
Analysis Of Sawdust By X-Ray Photoelectron Spectroscopy, Guilin Jiang, Ghaleb A. Husseini, Larry Lin Baxter, Matthew R. Linford
Faculty Publications
Determining the chemical structure and composition of biomass fuels using x-ray photoelectron spectroscopy XPS can provide fundamental knowledge of their structures that is useful in understanding and predicting their combustion behavior. Sawdust is an example of a forest product residue byproduct of paper and lumber production of potential interest for biomass combustion. The XPS spectra of sawdust provide both its elemental composition and indications of its bonding. Traditional fuel analyses of this fuel are also provided. These include: ultimate analysis — the elemental composition of the overall fuel C, H, N, S, and O; chlorine analysis — reported here as …
Analysis Of Sugar Beet Pulp By X-Ray Photoelectron Spectroscopy, Guilin Jiang, Ghaleb A. Husseini, Larry Lin Baxter, Matthew R. Linford
Analysis Of Sugar Beet Pulp By X-Ray Photoelectron Spectroscopy, Guilin Jiang, Ghaleb A. Husseini, Larry Lin Baxter, Matthew R. Linford
Faculty Publications
Determining the chemical structure and composition of biomass fuels using x-ray photoelectron spectroscopy XPS can provide fundamental knowledge of their structures that is useful in understanding and predicting their combustion behavior. Sugar beet pulp is an example of an agricultural residue byproduct of food and feed production of potential interest for biomass combustion. The XPS spectra of sugar beet pulp provide both its elemental composition and indications of its bonding. Traditional fuel analyses of this fuel are also provided. These include: ultimate analysis — the elemental composition of the overall fuel C, H, N, S, and O; chlorine analysis — …
Analysis Of Straw By X-Ray Photoelectron Spectroscopy, Guilin Jiang, Ghaleb A. Husseini, Larry Lin Baxter, Matthew R. Linford
Analysis Of Straw By X-Ray Photoelectron Spectroscopy, Guilin Jiang, Ghaleb A. Husseini, Larry Lin Baxter, Matthew R. Linford
Faculty Publications
Determining the chemical structure and composition of biomass fuels using x-ray photoelectron spectroscopy XPS can provide fundamental knowledge of their structures that is useful in understanding and predicting their combustion behavior. Straw is an example of an agricultural residue byproduct of food and feed production of potential interest for biomass combustion. The XPS spectra of straw provide both its elemental composition and indications of its bonding. Traditional fuel analyses of this fuel are also provided. These include: ultimate analysis — the elemental composition of the overall fuel C, H, N, S, and O; chlorine analysis — reported here as part …