Engineering Commons^™

Maximizing Charge Dynamics In Znin2s4/Cn Van Der Waals Heterojunction For Optimal Hydrogen Production From Photoreforming Of Glucose, Jinqiang Zhang, Xinyuan Xu, Lei Shi, Huayang Zhang, Shaobin Wang, Hongqi Sun

Research outputs 2022 to 2026

Biomass photoreforming stands out as a promising avenue for green hydrogen, leveraging solar energy for the generation and transformation of clean and renewable energy resources. The pursuit of efficient photocatalysts is motivated by the unsatisfied hydrogen evolution performance arising from the complex and stubborn structure of biomass. Herein, we loaded 2-dimensional (2D) ZnIn2S4 onto 2D carbon nitride nanosheets, resulting in the formation of Van der Waals (VDW) heterojunctions (ZIS/CN). Band structure and morphology of CN were rationally tailored through precursor engineering to effectively magnify interfacial internal electric field and minimize diffusion pathway within the VDW heterostructure, realizing optimal charge dynamics …

Evaluation Of Biomass As Bio-Additive In 3d Printing, Shuyang Zhang

Doctoral Dissertations

The petrol-based polymer has been widely applied in current daily life. The end-of-life of polymeric products has drawn environmental concerns. One of the solutions to such issues is to use bio-renewable materials to replace or reduce the use of petrol-based materials. Lignocellulosic materials are one of the potential candidates. Along with the features of 3D printing and the unique properties of biomass, 3D-printed biomass-based materials could be promising in preparing sustainable alternatives.

In this dissertation, lignin and other biomass were applied to various 3D printing techniques for sustainable composites. Stereolithography (SLA) was first used, and the kraft softwood lignin was …

Improving Lignin Recovery From Paper Mill And Biorefinery Waste Streams Via Liquid-Phase Splitting, Carter Fitzgerald

All Dissertations

Lignin is an abundant biopolymer with significant promise due to its aromaticity. It has been targeted as a replacement for a number of petroleum-based products including adhesives, coatings, polyurethane foams, activated carbon, and carbon fibers. However, commercially available bulk lignins are too polydisperse, and contain too many residual metals from the pulping process that are detrimental to the properties of the final product.

The Sequential Liquid-lignin Recovery and Purification (SLRP) process was developed by Michael Lake and John Blackburn, in collaboration with Clemson, with the intention of creating a continuous method for recovering lignin from paper-mill black liquors. Thies and …

Hydrothermal Liquefaction (Htl) Of Lignocellulosic Biomass For Biocrude Production: Reaction Kinetics And Corrosion-Resistance Performance Of Candidate Alloys For Reactors, Haoyu Wang

Electronic Thesis and Dissertation Repository

In recent years, the rapid increase in the demand for clean energy and green chemicals as well as concerns over the supply and environmental impacts associated with fossil. resources have stimulated intensive research on conversion of bioresources, such as lignocellulosic biomass and biowaste, into energy, fuels, chemicals, and materials.

Hydrothermal liquefaction (HTL) is a unique thermochemical conversion process, particularly applicable for the conversion of wet biomass and biowaste feedstocks. Most of the biomass HTL studies are conducted in batch reactor and focus on the effects of catalysts, reaction temperature and time on production efficiency and chemical properties of the products. …

Partially Oxidative Torrefaction Of Woody Biomass Pellets: Burning Behaviour And Emission Analysis, Sajid Riaz, Yasir M. Al-Abdeli, Ibukun Oluwoye

Research outputs 2022 to 2026

Non-conventional torrefaction under partially oxidative conditions is an emerging cost-effective thermochemical pre-treatment method to improve the quality of biomass for energy applications. The literature lacks data on the combustion of biomass torrefied under oxygen-deficient atmosphere with actual reactor conditions (inevitable non-uniformities in the thermal environment). In this work, a dual mode fixed-bed biomass (torrefaction) reactor and combustor was operated on Australian biomass pellets, to torrefy the fuels at 275 °C for 30 min using partially oxidative atmosphere (O₂: 5 vol %, balance N₂) and then to combust them. Combustion behaviour with a particular focus on gaseous …

Engineering Lewis Acidic Materials For Biomass Conversion And Battery Applications., Md Anwar Hossain

Electronic Theses and Dissertations

My long-term goal is to develop catalytic systems to produce renewable energy for a sustainable society. The overall research objective of my dissertation is to advance understanding of Lewis acidic materials for (1) conversion of renewable lignin into phenolics and (2) enhanced cycling stability of lithium metal batteries to safely store renewable electricity from wind and solar, thereby laying the groundwork for our transition to a sustainable society. Petroleum is a conventional feedstock for current transportation fuels (gasoline, diesel, and jet fuels). However, petroleum is a finite resource and produces greenhouse gases (CO₂ and CH₄) upon processing, …

Co-Gasification Of Biomass And Plastic Waste In A Bubbling Fluidized Bed Reactor, Islam Elghamrawy

Electronic Thesis and Dissertation Repository

Plastics are versatile, durable, and can be manipulated to match different needs. The COVID-19 pandemic has demonstrated the importance of reducing plastic waste and is believed to be responsible for increasing the generation of plastic waste by 54,000 tons/day which was reported in 2020. Another widely available waste is biomass waste. Agriculture and agroforestry, forest and wood processing, municipal waste, and the food industry are all considered major producers of biowaste. Co-gasification is considered one of the most promising methods of chemical recycling that targets the production of syngas (hydrogen and carbon monoxide) and light hydrocarbon gases. In this study, …

Room Temperature Alkali Treatment Of Rice Straw For Enhanced Enzymatic Hydrolysis., Seth Mains

Electronic Theses and Dissertations

Due to the pollution of fossil fuels due to greenhouse emissions, researchers continue to search for alternative methods that allow for the clean production of energy, fuels, and polymer fibers. A method currently under investigation is the use of lignocellulosic biomass as a solution to current problems with energy and polymer fiber production. Through the process of pretreatment, possibilities for lignocellulosic biomass expand due to improved accessibility of the cellulose and hemicellulose which can be broken down via enzymatic hydrolysis into C5 and C6 sugars such as xylose and glucose. This study investigated the fermentation of the rice straw into …

Exploration Of The Sludge Biodiesel Pathway, Zachary Christman

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

Wastewater sludge is an overlooked source of fat, oil, and grease (FOG) that could be converted into biodiesel. The United States produces about 8 million tons of sludge per year. The disposal cost for this amount of sludge is about 2 billion dollars. The widespread availability and low cost of sludge compared to other biodiesel raw materials make it an economical choice for a renewable fuel. Using sludge as a raw material can produce 25 to 30 mg per gram of fatty acid methyl ester (FAME); the main component of biodiesel. Sludge biodiesel has the potential of transforming a portion …

Nsf Career Award Supports Schwartz's Research On The Chemical Process For Making Rubber Component, Marcus Wolf

General University of Maine Publications

advance his ongoing dissection of the Lebedev process. The well-known, multi-step chemical reaction is used to make butadiene from biomass-derived ethanol. However, little research has been conducted on the Lebedev process at the molecular level. Understanding the intricacies of this process will help researchers create new catalysts necessary for the chemical reactions to make goods from both petroleum and biomass, that would increase butadiene yield.

Biomass-Derived Electrode Materials And Sustainable Processes For Supercapacitors, Katelyn M. Shell

Theses and Dissertations

Biomass is one of the most abundant natural resources and has been used as a source of energy for thousands of years. Biomass as a precursor for energy storage materials is still relatively novel and faces several obstacles before becoming commonly used in today’s electrical devices. Currently, energy storage devices, such as batteries, capacitors, and supercapacitors, utilize petroleum-derived graphitic carbons for anodes, generating a need for more sustainable materials. Biomass, as a carbon-rich source for electrode materials, presents a viable and economically feasible alternative due to the prevalent lignocellulosic compounds: lignin, cellulose, and hemicellulose. Preliminary studies on the solid residues …

Understanding Biomass Upgrading Through Hydrogenolysis Reactions: Kinetics And Mechanism, Jalal Tavana

Electronic Theses and Dissertations

This dissertation involves several hydrogenolysis reactions but is mainly focused on hydrodechlorination (HDC) of chlorobenzene (PhCl) and hydrodeoxygenation (HDO) of 2-furancarboxylic acid (FCA). Hydrodechlorination of PhCl has been the subject of research for some time. Here, we used a Pd/C catalyst to study this reaction though rigorous kinetics and mechanistic analyses in a CSTR reactor. The H₂/D₂ kinetic isotope effect (KIE) experiment revealed that H₂ is not involved in a rate controlling step. The kinetics data are in agreement with similar systems reported before and follow a first-order dependence on chlorobenzene, half order for hydrogen and …

Reaction Kinetics And Mechanism Investigations Of Renewable Chemicals Production From Biomass, Hussein Talib Abdulrazzaq

Electronic Theses and Dissertations

The development of the technologies and the improved processes for the production of high value bio-based chemicals is one of the most important challenges at the present time. This new movement is not only important from an environmental perspective, but also it is a profitable approach to provide affordable and efficient processes. Therefore, the chemical catalytic upgrading processes over various homogenous and heterogeneous catalysis could be an outstanding modification to upgrade biomass-derived platform molecule to high value applications. In this dissertation, we highlight our recent progress in developing new chemistries and processes for upgrading biomass-derived molecules and address the challenges …

Challenges To Levulinic Acid And Humins Valuation In The Sugarcane Bagasse Biorefinery Concept, Emília Savioli Lopes, Jean Felipe Leal Silva, Elmer Ccopa Rivera, Alana Petrina Gomes, Melina Savioli Lopes, Rubens Maciel Filho, Laura Plazas Tovar

Faculty Publications

© 2020, Springer Science+Business Media, LLC, part of Springer Nature. Levulinic acid (LA) is currently one of the most promising chemicals derived from biomass. However, its large-scale production is hampered by the challenges in biomass hydrolysis and the poor selectivity due to the formation of humins (HUs). This study addresses these challenges using the biorefinery concept of biomass fractionation. A three-step process (pretreatment, delignification, and acid-catalyzed conversion) was optimized to produce LA from SCB considering the yield (YLA), efficiency (ELA), and concentration of LA (CLA) as functions of temperature, reaction time, acid concentration, and solids loading. By means of a …

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 …

Development And Characterization Of Robust And Cost-Effective Catalysts For Selective Biomass Upgrading To Fuels And Chemicals By Deoxydehydration, Bryan E. Sharkey

Doctoral Dissertations

The use of biomass-derived ligno-cellulose as a possible alternative source of fuels and chemicals to fossil-based hydrocarbons, however, biomass offers many challenges based on processing and its high oxygen content. One promising upgrading route is deoxydehydration, a reaction which combines a deoxygenation by a sacrificial reductant and dehydration in a single step to selectively convert vicinal diols into an olefin. This reaction is highly selective when using homogeneous oxo-rhenium catalysts, which can easily undergo the necessary changes in coordination and oxidation state, however the high cost of rhenium and difficulty of homogeneous catalyst recovery make these catalysts untenable for large …

Bubble Dynamics In A Sand Fluidized Bed In The Presence Of Biomass Pellets, Nicolas Torres Brauer

Electronic Thesis and Dissertation Repository

Given the worldwide concerns regarding fossil fuel availability, global warming, water, and air pollution and economy needs, there is an urgent requirement to develop and implement alternative energies. Biomass gasification can consume vegetal waste to produce syngas, which is a mix of carbon monoxide, hydrogen, and carbon dioxide. When biomass gasification is carried out in a fluidized bed, the process is highly efficient.

The experimental study of the present Ph.D. dissertation took place in a Plexiglas 0.44 m diameter unit, equipped with a CREC Optiprobe system and a video camera. The unit was filled with 200-900 µm sand particles and …

Elucidating The Properties And Mechanism For Cellulose Dissolution In Tetrabutylphosphonium-Based Ionic Liquids Using High Concentrations Of Water, Brad Crawford

Graduate Theses, Dissertations, and Problem Reports

The structural, transport, and thermodynamic properties related to cellulose dissolution by tetrabutylphosphonium chloride (TBPCl) and tetrabutylphosphonium hydroxide (TBPH)-water mixtures have been calculated via molecular dynamics simulations. For both ionic liquid (IL)-water solutions, water veins begin to form between the TBPs interlocking arms at 80 mol % water, opening a pathway for the diffusion of the anions, cations, and water. The water veins allow for a diffusion regime shift in the concentration region from 80 to 92.5 mol % water, providing a higher probability of solvent interaction with the dissolving cellulose strand. The hydrogen bonding was compared between small and large …

Exploring Methodologies To Improve Lignin Utilization In Biorefineries, James Meyer

McKelvey School of Engineering Theses & Dissertations

The increasing world population, coupled with an improving quality of life, has driven a rapidly increasing demand for fuels, chemicals, and materials. Fossil carbon feedstocks, such as petroleum, are currently being consumed to meet these demands. The utilization of these feedstocks has negative impacts on human and environmental health, which are undoubtedly intensifying as a result of the increased reliance required to meet these demands. As an alternative way to meet these demands, biorefineries generate a wide range of fuels, chemicals, and materials from biomass, a renewable and sustainable resource. Current second-generation biorefineries use a plant-based feedstock, lignocellulosic biomass, comprised …

Heterogeneous Catalysis For The Upgrading Of Biomass Derived Chemicals Via Hydrodeoxygenation, Elizabeth Barrow

Theses and Dissertations

An important step in the upgrading of biomass derived chemicals is the removal of excess oxygen. The works reported here are focused on studying the heterogeneous catalysts that can be utilized for that upgrading through hydrodeoxygenation. This work begins with a discussion of the alkylation of short chain platform chemicals for chain growth and also demonstrates the proof of concept of combining alkylation and hydrodeoxygenation in a single step. Then, because of the promising nature of ReOx- Pd/CeO2 for selective hydrodeoxygenation, a detailed study of ReOx/CeO2 is presented. Finally, a new surface structure interpretation is presented for P/Ni(111) which could …

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 …

Literature Survey Of Wet-Waste And Hydrothermal Carbonization System: A Comparative Evaluation, Ramat Olaide Yusuf

Dissertations and Theses

This thesis describes the process of Hydrothermal carbonization and a comparative assessment on recent work done on the process using different feedstocks such as Raw Apple (RA), Apple chip pomace (ACP), apple juice pomace (AJP), grape pomace (GP), macadamia nut-shell (MNS), Sewage Sludge (SS), Poultry Litter (PL) and Grape Marc (GM). The data obtained from the literature survey was compared with the data obtained by the CCL team on the SWPS gasifier (HTC of poultry litter) to obtain how carbon conversion efficiency, syngas composition, thermal efficiency, char production rate, gas production rate and energy utilization vary with carbonization process conditions, …

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 …

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

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

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 …

Lignin Conversion To Value-Added Products Via Heterogeneous Catalysts, Yu Gao

McKelvey School of Engineering Theses & Dissertations

Increasing world population has led to great demands for fuels, chemicals, and materials, and has raised concerns over the depletion of non-renewable resources and the environmental impacts of their processing and utilization. However, the biorefinery concept suggests lignocellulosic biomass can be used as an alternative resource for producing a range of fuels, chemicals and materials to fulfill these demands in a sustainable way. Hence, fermentation technologies are widely developed to efficiently utilize lignocellulosic carbohydrates. However, the non-carbohydrate fraction of biomass, lignin, is still considered as waste and is under-utilized as low-grade fuel, mainly for local heat and electricity production. Since …

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 …

Experimental And Numerical Investigation On Tar Production And Recycling In Fixed Bed Biomass Gasifiers, Jia Yu

Doctoral Dissertations

"Bioenergy has been utilized for domestic purposes since pre-recorded history and it catches the highlight in the recent decades because it naturally benefits the world climate and energy security. Gasification is one of the key technologies to efficiently and economically convert biomass into syngas and further into biofuels. Despite these outstanding advantages, biomass gasification suffers from the formation of unfavorable byproduct tar and the consequential tar elimination. Moreover, the collected tar is toxic and thus requires storage and strict deposit method to avoid environmental pollution.

To understand the mechanisms of biomass gasification and tar production, simulations with Aspen Plus were …

Experimental Study Of The Chimney Height Variation Against Double Pots Biomass Stove Performance, Faisal Faisal, Adi Setiawan, Wusnah Wusnah, Khairil Khairil, Luthfi Luthfi, Mona Fajriana

Makara Journal of Technology

This research aims to get optimal chimneys height of double pots biomass stove. Optimal chimneys height needs to provide best performance of the stove. Experimental study was done by varied the chimney heights. Water boiling test as the standard method was used to obtained stove performance for each chimney height variation. The results showed that best performance stove was the one with 1.65 cm chimney height, with thermal efficiency at 37.66%.