Chemical Engineering Commons^™

Utilizing Coal For Mesophase Pitch-Based Carbon Fiber Production: Precursors, Processes, And Progress, Christina M. Thompson

Theses and Dissertations--Chemistry

Graphitic materials possess unique properties due to the unique combination of layered crystalline structure and carbon’s low atomic weight. High performance carbon fiber is one such example, displaying exceptional strength-to-weight ratios, stiffness, and thermal and chemical resistance. These properties render high performance carbon fiber a critical structural reinforcement material in the manufacture of composites across various industries, such as for automotive and aerospace applications. However, balancing fiber performance with precursor and processing costs remains a challenge. As alternative carbonaceous feedstocks are explored, coal has gained interest for utilization in graphitic products as a relatively abundant and low-cost source of aromatic …

Evaluating Coal-Jatropha Curcas Composite Briquettes As Sustainable Fuel Alternatives, Amad Ullah Khan, Muhammad Saleem, Muhammad Abas, Zakir Ullah, Khan Muhammad, Farida Anjum, Aamer Sharif, Melkamu Tadesse Getachew

Research outputs 2022 to 2026

Coal is a major fuel source but raises environmental concerns. This study investigated the feasibility of utilizing a composite briquette sustainable fuel produced from subbituminous coal and Jatropha curcas biomass. Briquettes were prepared with varying weight ratios of coal to J. curcas biomass (90:0–0:90) using corn starch as a binder. The influence of this ratio on the briquettes’ properties was comprehensively evaluated through proximate analysis, ultimate analysis, scanning electron microscopy (SEM), and X-ray fluorescence (XRF) analysis. The results revealed that increasing the J. curcas content in the briquettes gradually decreased the moisture content, ash content, and fixed carbon content while …

The Hole Sealing Technology Of Solid-Liquid Materials With Three Pluggings And Two Injections For Gas Extraction Hole In The Coal Mine, Shiyao Yu, Xianbo Su, Jinxing Song, Qian Wang, Zhenjiang You

Research outputs 2022 to 2026

The sealing quality of the gas extraction holes determines the extracted gas concentration. Based on this, the paper reveals the basic principle of hole sealing by analyzing the gas leakage mechanism of the borehole. The hole sealing technology of solid-liquid materials with three pluggings and two injections for the gas extraction hole is proposed, and the hole sealing device and material are developed. Through testing the granularity distribution of the solid material, as well as the surface tension and contact angle of the slurry, the hole sealing material that can meet the requirements of accessible, sticky, and anti-deformation is selected. …

No Formation During Co-Combustion Of Coal With Two Thermally Treated Biomasses, Thomas Allgurén, Klas Andersson, Andrew R. Fry, Eric G. Eddings

Faculty Publications

The combustion behavior of biomass as a fuel varies dependent on source of the raw material, but also on the type of pre-treatment. In this work steam exploded and torrefied woody biomass were studied with respect to NOx formation in co-firing experiments. Most of the reported data is based on small scale experiments and simulations. In this work, however, have three different cases been investigated experimentally in a 1.5MWth combustor supported by reaction simulations. One case corresponds to firing 100% Utah bituminous coal and two cases where 15% of the coal (on a mass basis) has been replaced with either …

Hydrogen Diffusion In Coal: Implications For Hydrogen Geo‐Storage, Alireza Keshavarz, Hussein R. Abid, Muhammad Ali, Sefan Iglauer

Research outputs 2014 to 2021

Hypothesis

Hydrogen geo-storage is considered as an option for large scale hydrogen storage in a full-scale hydrogen economy. Among different types of subsurface formations, coal seams look to be one of the best suitable options as coal’s micro/nano pore structure can adsorb a huge amount of gas (e.g. hydrogen) which can be withdrawn again once needed. However, literature lacks fundamental data regarding H₂ diffusion in coal.

Experiments

In this study, we measured H₂ adsorption rate in an Australian anthracite coal sample at isothermal conditions for four different temperatures (20 °C, 30 °C, 45 °C and 60 °C), at …

Modeling Ash Deposit Growth Rates For A Wide Range Of Solid Fuels In A 100 Kw Combustor, Seyedhassan Fakourian, Zachary Mcallister, Andrew R. Fry, Yueming Wang, Xiaolong Li, Jost O.L. Wendt, Jinze Dai

Faculty Publications

This work details a model for evaluating the relative ash deposition propensity of various solid fuels without the complicated spatial considerations included in CFD modeling. Four deposition mechanisms are included, namely: inertial impaction, thermophoresis, condensation, and eddy impaction. This model has been validated and shown to effectively predict ash deposit rates for a wide range of solid fuels including coal, biomass, and their blends, burned in a 100 kW rated downflow combustor. Specifically, this work presents and compares two separate models for the sticking efficiency of impacting ash particles on a coupon surface: the melt fraction stickiness …

Hydrogen Adsorption On Sub-Bituminous Coal: Implications For Hydrogen Geo-Storage, Sefan Iglauer, Hussein Abid, Ahmed Z. Al-Yaseri, Alireza Keshavarz

Research outputs 2014 to 2021

Hydrogen is a clean fuel that can potentially revolutionize the energy supply chain and decarbonize fuel consumption. However, a key hurdle that needs to be overcome before a full-scale hydrogen economy can be established is hydrogen storage which is currently the main limitation. Here, we propose that hydrogen gas can be stored in underground coal seams, where it adsorbs on the coal surface. However, currently, no hard data related to such a procedure exists. We, therefore, demonstrate experimentally that significant amounts of hydrogen gas can be stored via this route. Hydrogen adsorption capacities reached 0.6 moles H₂/kg of …

Dry Reforming Of Methane Using Microwave Irradiated Metal Oxide/Coal Char Catalysts, Anthony Carter

Graduate Theses, Dissertations, and Problem Reports (ETD)

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) …

Particle Studies In The Lab And Pilot-Scale Coal Combustion Systems, Dishant Khatri

McKelvey School of Engineering Graduate Student Theses & Dissertations

In the past century, coal contributed more to the global electricity supply than any other source. Currently, it alone accounts for over 35% of the global electricity supply. Though coal is globally well-distributed and can provide cheap, stable, and reliable energy on demand, it emits a large amount of carbon dioxide—a greenhouse gas responsible for global warming. Additionally, it is a major source of particulate matter (PM) pollution. Thus, in recent years, to reduce the impact of coal on climate, several policies have been introduced to phase out coal. However, replacing coal with intermittent renewables has led to a reduction …

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 …

Direct Carbon Solid Oxide Fuel Cells, Jiang Liu, Xiao-Min Yan

Journal of Electrochemistry

Carbon is richly reserved in coal, biomasses, and many other nature resources. It is usually used as an energy source through oxygen oxidation reaction. The oxidation is generally realized through combustion which causes serious air pollution. Besides, the conversion efficiency of generating electricity through the combustion process is limited by Carnot efficiency. A direct carbon solid oxide fuel cell (DC-SOFC) is a solid oxide fuel cell (SOFC) directly operated with solid carbon as the fuel. It can convert the chemical energy of carbon into electricity with high efficiency. The concentration of produced CO₂ from a DC-SOFC is so high …

A Review Of 30 Years Of Research Using The Cpd Model, Thomas H. Fletcher

Faculty Publications

The chemical percolation devolatilization (CPD) model for coal pyrolysis was first published in 1989, and a completed version that included the vapor–liquid equilibrium model and cross-linking model was published in 1992. The CPD model was one of three pyrolysis models developed using a lattice model to account for the chemical structure of the coal and was directly based on solid-state ¹³C nuclear magnetic resonance (NMR) measurements of the coal structure. A correlation of coal structure parameters measured by NMR spectroscopy was performed to permit use of the CPD model to determine pyrolysis rates and yields of tars and light …

Reduction Of A Detailed Soot Model For Simulations Of Pyrolysing Solid Fuels, Alexander J. Josephson, Emily M. Hopkins, David O. Lignell, Rod R. Linn

Faculty Publications

This work presents a computationally inexpensive soot formation model for use in simulating large solid-complex fuel systems. The proposed model evaluates three variables: number density of tars, bulk mass density of soot particles, and particle number density. Each of these variables are influenced by soot formation phenomena, and this model evaluates the most common of these phenomena: soot nucleation, surface reactions, and coagulation. Two separate simulations were carried out using this model and results were compared against simulations using a more detailed and computationally expensive model. Results are promising and show a meaningful reduction in model complexity and computational cost …

Review Of Carbonaceous Annealing Effects On O2 And Co2 Coal Reactivity, Troy Michael Holland, Thomas H. Fletcher, Osvalda Senneca

Faculty Publications

Coal is, and will remain for the foreseeable future, a critical energy production resource. Advanced models of coal conversion behavior in air and oxy-coal environments enhance the boiler operational efficiency and design optimization. Although coal conversion models have continuously improved over decades of research, not all aspects of coal particle heating and conversion have received equal treatment. Coal particle annealing is one aspect of the coal conversion process that is simultaneously highly sensitive to the conversion environment, exceptionally impactful on coal chemistry, and frequently neglected in coal models. However, the current body of literature has explored numerous aspects of coal …

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 …

Analysis Of Particle Behavior Inside The Classifier Of A Raymond Bowl Mill While Co-Milling Woody Biomass With Coal, Seyedhassan Fakourian, Andrew R. Fry, Tanner Jasperson

Faculty Publications

Woody biomass cofiring with coal at existing pulverized-coal boilers is known to be a green energy source and is a low-expense alternative for pure coal combustion. Co-milling woody biomass particles (15 wt%) with coal particles (85 wt%) before burning at a boiler is a complex problem because large woody biomass particles (>300 μm) exit the milling system along with the fine particles. A Computational Particle Fluid Dynamics (CPFD) is used in this paper to present a novel analysis about the behavior of woody biomass particles as they are mixed with coal particles inside the classifier. To meet this …

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 …

Modeling Soot Formation From Solid Complex Fuels, Alexander J. Josephson, Rod R. Linn, David O. Lignell

Faculty Publications

A detailed model is proposed for predicting soot formation from complex solid fuels. The proposed model resolves two particle size distributions, one for soot precursors and another for soot particles. The precursor size distribution is represented with a sectional approach while the soot particle-size distribution is represented with the method of moments and an interpolative closure method is used to resolve fractional methods. Based on established mechanisms, this model includes submodels for precursor coagulation, growth, and consumption, as well as soot nucleation, surface growth, agglomeration, and consumption. The model is validated with comparisons to experimental data for two …

Fundamental Studies Of Solid-Fuel Combustion Using A Two-Stage Flat-Flame Burner, Adewale Ayodeji Adeosun

McKelvey School of Engineering Graduate Student Theses & Dissertations

Innovative coal technologies are essential for addressing concerns about air pollution and global climate change. A key pathway to advancing these technologies is through developing a thorough understanding of the fundamental physical and chemical processes that occur during coal combustion. Ignition influences many aspects of coal combustion, including flame stability, submicron aerosol evolution, and char burnout. As important as ignition and these associated processes are, they are challenging to study because they depend on many factors, such as the combustion environment, particle size, and particle-particle interactions.

While there have been many studies of coal ignition, none have studied the process …

Evaluation And Prevention Of Spontaneous Combustion During Handling And Storage Of Coal, Amir E. Najarzadeh

Theses and Dissertations--Mining Engineering

Spontaneous combustion of coal has historically been a major problem for the coal industry, predominantly during storage and transportation. Various methods have been used in the laboratory for evaluating the propensity of different coal sources to self-heat. However, the heterogeneity of coal and the complexity of the system has resulted in inconsistencies and sometimes conflicting results as indicated by the findings reported in several publications.

The primary objective of the current study was to build a laboratory scale apparatus that simulates the condition of a coal stockpile to evaluate the events leading to spontaneous combustion and develop potential remedies. As …

Particle Deposition Behavior From Coal-Derived Syngas In Gas Turbines At Modern Turbine Inlet Temperatures, Robert Laycock

Theses and Dissertations

Certain types of fuel used for combustion in land-based gas turbines can contain traces of ash when introduced into a gas turbine. Examples include synfuel, from the gasification of coal, and heavy fuel oil. When these ash particles travel through the hot gas path of the gas turbine they can deposit on turbine vanes and blades. As deposits grow, they can reduce turbine efficiency and damage turbine hardware. As turbine inlet temperatures increase, ash deposition rates increase as well.Experiments were conducted in the Turbine Accelerated Deposition Facility (TADF) at Brigham Young University to better understand ash deposition behavior at modern …

Modeling Effects Of Annealing On Coal Char Reactivity To O2 And Co2, Based On Preparation Conditions, Troy Michael Holland, Sham Bhat, Peter Marcy, James Gattiker, Joel D. Kress, Thomas H. Fletcher

Faculty Publications

Oxy-fired coal combustion is a promising potential carbon capture technology. Predictive computational fluid dynamics (CFD) simulations are valuable tools in evaluating and deploying oxyfuel and other carbon capture technologies, either as retrofit technologies or for new construction. However, accurate predictive combustor simulations require physically realistic submodels with low computational requirements. A recent sensitivity analysis of a detailed char conversion model (Char Conversion Kinetics (CCK)) found thermal annealing to be an extremely sensitive submodel. In the present work, further analysis of the previous annealing model revealed significant disagreement with numerous datasets from experiments performed after that annealing model was developed. The …

Comprehensive Model Of Single Particle Pulverized Coal Combustion Extended To Oxy-Coal Conditions, Troy Michael Holland, Thomas H. Fletcher

Faculty Publications

Oxy-fired coal combustion is a promising potential carbon capture technology. Predictive CFD simulations are valuable tools in evaluating and deploying oxy-fuel and other carbon capture technologies either as retrofit technologies or for new construction. However, accurate predictive simulations require physically realistic submodels with low computational requirements. In particular, comprehensive char oxidation and gasification models have been developed that describe multiple reaction and diffusion processes. This work extends a comprehensive char conversion code (CCK), which treats surface oxidation and gasification reactions as well as processes such as film diffusion, pore diffusion, ash encapsulation, and annealing. In this work several submodels in …

Modelling Of Coal-Biomass Blends Gasification And Power Plant Revamp Alternatives In Egypt’S Natural Gas Sector, Dalia A. Ali Eng, Mamdouh A. Gadalla Prof., Omar Y. Abdelaziz, Fatma H. Ashour Prof.

Chemical Engineering

Recently, there has been a growing research interest in the co-gasification of biomass with coal to produce syngas and electricity in a sustainable manner. Co-gasification technology do not only decrease potentially the exploitation of a significant amount of conventional coal resources, and thus lower greenhouse gases (GHG) emissions, but also boost the overall gasification process efficiency. In the present work, a rigorous simulation model of an entrained flow gasifier is developed using the Aspen Plus® software environment. The proposed simulation model is tested for an American coal and the model validation is performed in good agreement with practical data. The …

Global Sensitivity Analysis For A Comprehensive Char Conversion Model In Oxy-Fuel Conditions, Troy Michael Holland, Thomas H. Fletcher

Faculty Publications

Oxy-fired coal combustion is a promising potential carbon capture technology. Predictive CFD simulations are valuable tools in evaluating and deploying oxy-fuel and other carbon capture technologies either as retrofit technologies or for new construction. However, accurate predictive simulations require physically realistic submodels with low computational requirements. In particular, comprehensive char oxidation and gasification models have been developed that describe multiple reaction and diffusion processes. This work focuses on the sensitivity of a recent comprehensive char conversion code named CCK, which treats surface oxidation and gasification reactions as well as the processes such as film diffusion, pore diffusion, ash encapsulation, and …

A Comparison Of Simple Global Kinetic Models For Coal Devolatilization With The Cpd Model, Andrew Richards, Thomas H. Fletcher

Faculty Publications

Simulations of coal combustors and gasifiers generally cannot incorporate the complexities of advanced pyrolysis models, and hence there is interest in evaluating simpler models over ranges of temperature and heating rate that are applicable to the furnace of interest. In this paper, six different simple model forms are compared to predictions made by the Chemical Percolation Devolatilization (CPD) model. The model forms included three modified one-step models, a simple two-step model, and two new modified two-step models. These simple model forms were compared over a wide range of heating rates (5000 to 10⁶ K/s) at final temperatures up to …

Gasification Of Coal And Heat Integration Modification For Igcc - Integrated Gasification Combined Cycle, Dalia A. Ali Eng, Mamdouh A. Gadalla Prof., Fatma H. Ashour Prof.

Chemical Engineering

Use of energy is closely related to the development of an economy. The most useful form of energy in the modern world is electricity. IGCC has higher fuel flexibility (biomass, refinery residues, petroleum coke, etc.) and generates multiple products (electricity, hydrogen and chemicals like methanol and higher alcohols) and by-products - sulphur, sulphuric acid, slag, etc. IGCC plants include coal preparation unit, air separation unit (ASU) to separate oxygen from air to use it in the gasification process, gasification unit where an incomplete combustion for coal is made to produce Syngas, cleaning unit to remove acid gases and CO2 from …

Effects Of Biomass Moisture Content On Volatile Flame Length During Cofiring With Coal, Matthew Pollard

McKelvey School of Engineering Graduate Student 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 …

Steam Gasification Rates Of Three Bituminous Coal Chars In An Entrained-Flow Reactor At Pressurized Conditions, Aaron D. Lewis, Troy M. Holland, Nathaniel R. Marchant, Emmett G. Fletcher, Danley J. Henley, Eric G. Fuller, Thomas H. Fletcher

Faculty Publications

Three bituminous coal chars (Illinois #6, Utah Skyline, and Pittsburgh #8) were gasified separately at total pressures of 10 and 15 atm in an entrained-flow reactor using gas temperatures up to 1830 K and particle residence times gasification, although select experiments were performed at conditions where significant mass release was due to gasification by both H2O and CO2. The measured coal data were fit to three char gasification models including a simple first-order global model, as well as the CCKN and CCK models that stem from the CBK model. The optimal kinetic parameters for each of the three models are …

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 …