Stephen Kelley
Reuben B Robertson Professor Emeritus
Bio
Dr. Steve Kelley is a Professor at North Carolina State University and interim Department Head. His research interests include the sustainable production of energy and materials from biomass, and the application of novel analytical tools to biomass. He teaches classes in Wood Chemistry (FB 301) and Wood Adhesives and Composites (FB 444). In addition to his research and teaching, he has also helped develop international partnerships for the Department.
Prior to joining NCSU, he spent 13 years at the DOE’s National Renewable Energy Laboratory (NREL) working on biomass conversion technologies. At NREL his responsibilities included technical leadership and innovation in the areas of biomass characterization, production of value-added biobased products and thermal conversion processes, and project management. He left NREL as a Principal Scientist. Prior to joining NREL, he worked in industry (Eastman Chemical Co. and Bend Research, Inc.) for 7 years developing new cellulose-based materials and membrane processes.
Research
Bioethanol from Wood Hemicelluloses (Jameel, Phillips, Chang, Kelley) This collection of projects involve the production of ethanol from hemicellulose sugars extracted woody biomass. The work includes wood extraction; characterization of the extracts and extracted wood; clean-up of the extracted sugars; ethanol production; technoeconomic modeling of the process.
Woody Biomass Quality Study (Hazel, Kelley)This collection of projects is focused on measuring the chemical composition and physical properties of many sources of woody biomass and developing an understanding on the biomass resource impacts the cost of converting the biomass into fuels and products.
Thermochemical Conversion of Woody Biomass (Jameel, Peretti, Dayton, Kelley)This work is focused on developing thermochemical process for converting biomass into fuels and products. This work includes a recent $3.2 million DOE funded demonstration project that includes work at NCSU, Research Triangle International (Dayton), and the University of Utah (Winger), that will demonstrate gasification of wood biomass, novel gas cleanup catalysts, and gas-to-liquids production.
Cellulose Based Materials (Rojas, Heitmann, Kelley) This work includes the preparation and characterization of cellulose polymers, copolymers and blends. In particular this work is focused on the molecular level mixing behavior of cellulose copolymers and blends of cellulose copolymers with other organic and inorganic polymers.
Area(s) of Expertise
Sustainable production of energy and materials from biomass, and the application of novel analytical tools to biomass
Publications
- Catalytic graphitization of pyrolysis oil for anode application in lithium-ion batteries , GREEN CHEMISTRY (2024)
- Evaluating biomass sustainability: Why below-ground carbon sequestration matters , JOURNAL OF CLEANER PRODUCTION (2024)
- Exploring potential of cellulose acetate sulfate films for sustainable packaging: tuning characteristics via sulfate group variation , CELLULOSE (2024)
- Novel Correlation of Peroxide/Conjugation Values for Vegetable Oils During Deep-Frying , JOURNAL OF FOOD PROCESSING AND PRESERVATION (2024)
- Phenolic Resin Derived Hard Carbon Anode for Sodium-Ion Batteries: A Review , ACS ENERGY LETTERS (2024)
- Single-Component Cellulose Acetate Sulfate Hydrogels for Direct Ink Writing 3D Printing , BIOMACROMOLECULES (2024)
- Understanding the formation of insoluble gel particles during cellulose diacetate production , CELLULOSE (2024)
- Effective toluene removal from aqueous solutions using fast pyrolysis-derived activated carbon from agricultural and forest residues: Isotherms and kinetics study , HELIYON (2023)
- Effects of tri-solvent and electrospinning condition on the morphology of cellulose acetate nanofibers , EGYPTIAN JOURNAL OF CHEMISTRY (2023)
- Environmental Life Cycle Assessment of Premium and Ultra Hygiene Tissue Products in the United States , BIORESOURCES (2023)
Grants
This proposal aims to develop bi-functional oxygen and CO2 sorbents for chemical looping gasification of solids wastes with in-situ syngas conditioning. The novel material and gasification system will eliminate the needs for air separation and syngas conditioning/separation operations. The resulting syngas can readily be used for methane formation. A circulating fluidized bed gasification system and suitable bi-functional sorbents will be developed and demonstrated.
We will improve and validate the critical unit operations needed for producing high-value carbon materials (graphite and hard carbon) used for lithium ion and sodium ion batteries from a faction of the biocrude produced by biomass fast pyrolysis. This work will bring together two innovations, 1) production of high-value carbon materials from the biocrude heavy residues fraction, which are often difficult to convert into biofuels, and 2) process innovations that should lower the costs for producing these high-value carbons. In order to produce high-value carbons, the biocrude residues are sequentially heated to remove volatiles and oxygen, polymerize the biomass carbons into graphene sheets, and in a second step form either highly crystalline graphite or disordered hard carbon. The graphite can be used in as drop-in anode material in existing commercial lithium ion battery (LIB) applications such as portable electronics and electric vehicles (EVs), while the hard carbon can be used in emerging and advancing battery applications, such as sodium ion battery (SIB) for grid electrochemical energy storage and LIB for hybrid batteries in EV with high capacity and good rate capability. The team has demonstrated that both graphite and hard carbon can be produced from pyrolysis biocrudes at laboratory scale and has measured their electrochemical performance in batteries. This work will optimize the range of operating parameters, with a focus on the complex interactions between the chemical changes and the heat and mass transfer characteristics of the reactor and increase the production scale to obtain mass and energy balances that are relevant for modeling commercial potential. The performance of the carbon materials will be evaluated to define their values in commercial systems. Both techno-economics (TEA) and life cycle analysis (LCA) will be performed to understand the economic and environmental impact of the proposed technology. Preliminary revenue analysis suggests diverting 15-25% of the biocrude, essentially all of the heavy and less valuable fraction, into high-value carbons like graphite or hard carbon can significantly improve the profits of a biorefinery and lower the cost of making biofuels. The goal of this project is to optimize and scale-up the process for producing graphite and hard carbon that meet the requirement for LIB and SIB, respectively. Performance specification will be measured, including electrochemical performance under varying conditions (e.g., operating voltage range, current density, and c-rate) using coin-type and pouch cells. We will use a suite of advanced analytical tools to develop a more detailed understanding of 1) how the chemical composition of biocrude and the carbonization process impact the macromolecular ordering of the final products and 2) how the changes in carbon structure influence on the ion storage behavior (e.g., (de)insertion and adsorption/desorption) and subsequent electrochemical performance. In addition to the performance of the carbon materials, we will determine yields in order to close the mass and energy balances of the process. This data will be used to conduct rigorous TEA and LCA models to demonstrate the target FOA metrics such as $3.00/GGE fuel selling price and 60% reduction in emission. Successful completion of the scale up of bio-based graphite and hard carbon production will enable commercialization of these processes and will have an important impact on several sustainable technologies, 1) the low cost biocrude, the bio-based graphite will reduce the cost for LIB that can be used in EVs, 2) the low cost of hard carbon production will enable SIB for energy grid storage and LIB for advanced batteries for EVs, supporting continued growth of PV and wind electricity generation, and 3) commercial production of graphite and hard carbon as biorefinery co-products will improve the overall economics of producing biofuels.
The hygiene tissue industry (bath tissue and kitchen towel) is an annual 39 million tons - USD 100 billion - global market with a forecast to grow ~ 3% per year for the next decade [38], [39]. Most hygiene tissue paper grades require the use of both long and short virgin fibers, which provide strength and softness respectively [8]. As an effect of global megatrends, the demand for non-woody biomass for tissue manufacturing will continue to increase [40], and agricultural biomass, which is perceived to be a sustainable option, can be an important source of short fibers for the tissue industry [41]. Therefore, the need to research and create knowledge on the handling and conversion of biomass sorghum and switchgrass to produce sustainable and high-end fiber furnish for the hygiene tissue industry. The proposed feedstock can be established to supply fiber at industrial scale.
Loblolly pine is the most abundant commercially grown tree species in North Carolina with over 100,000 acres of pine plantations established each year in the state. In addition to the conventional forest products industry, loblolly pine serves as a promising source for renewable energy in the form of woody biomass. Large genetic differences exist for growth, disease resistance, and stem form. By planting genetically superior trees with desirable traits, it may be possible to substantially increase the amount and quality of biomass produced at a given site. The goal of this project is to evaluate different planting stock (families) in combination with different thinning regimes in order to inform forest landowners how best to maximize their returns when supplying both the bioenergy and sawtimber markets. This project was initiated in 2012, with the planting of a high spacing density (1037 trees/acre) long-term field trial in the NC Piedmont. The trial includes 10 of the best Coastal and 10 of the best Piedmont families with varying degrees of adaptation, growth, and wood characteristics. Different thinning regimes will be explored using eight year measurements, and the predicted financial returns from the thinnings as well as projected sawtimber production will be evaluated.
Overview Sub-Saharan Africa is the epicenter of the global challenge of energy poverty, with the absolute number of energy poor projected to increase through 2030. Energy poverty has implications for climate, environmental sustainability, human health, and well-being, with negative impacts realized at individual and collective-scales, and in local, regional, and global contexts. The complex socio-environmental challenge of energy poverty requires contributions from the basic, applied, and social sciences, and integration of evidence and learning using robust interdisciplinary frameworks. We will partner with and facilitate the networking of academic, practitioner, and policy communities in the US and Southern Africa to fill critical gaps in the theoretical and empirical evidence base regarding mitigating energy poverty. International partnership is critical to the identification of important and representative energy poverty innovations to study, to creating a network of institutions using common frameworks, research design, and empirical strategies, and to cultivating long-term interdisciplinary energy poverty research capacity in the Southern Africa region. Intellectual Merit Our aim is to build an interdisciplinary evidence base and network focused on energy poverty in Southern Africa, building capacity for transformative change. We center our research and capacity building around three themes: technology and incentives; space and place; and population and environment dynamics. We will measure the air quality, land use, and human welfare impacts of a representative set of technology and behavioral interventions designed to mitigate energy poverty. Based upon knowledge generated, we test new approaches for using and integrating appropriate technology and incentives to address energy poverty. In the second theme, we will investigate the spatial dimension of energy poverty by analyzing neighborhood effects as determinants of energy poverty, and consider the question of optimal scale of implementation of energy poverty interventions for maximizing environmental benefits and social welfare outcomes. Finally, we will investigate sustainable wood energy systems as a potential strategy for coping with the challenge of population and environment dynamics in the region, and analyze the associated environmental and economic synergies and trade-offs. This PIRE is innovative for several reasons. First, we use rigorous quantitative interdisciplinary impact evaluation as the anchor for our research and training program. We seek to study what works, why it works, and over what spatial and temporal scale. Second, the study of energy poverty is highly fragmented across a large number of disciplines with very little cross-fertilization or engagement with interdisciplinary frameworks including complex socio-ecological systems and population and environment dynamics. We use these important theoretical lenses to shed new light on this highly intractable problem, and to guide a coherent body of empirical research. Third, despite facing a looming crisis, energy poverty in Southern Africa is dramatically understudied. Broader Impacts Research findings from this study will provide new theoretical and empirical knowledge on energy poverty in sub-Saharan Africa to academics, practitioners, and policy makers. We will build new networks and promote collaborative research and exchange among over 50 scientists, graduate, and undergraduate students across the US and Southern Africa, with the aim of creating a robust interdisciplinary network of scholars. To facilitate this, we will coordinate a series of regional training workshops focused on interdisciplinary energy poverty research. A central component of the PIRE is continuous engagement with policy makers and practitioners. We will organize a series of regional policy workshops that will take place at regular intervals during the life of the Energy Poverty PIRE. We propose several innovations in teaching and scholarship that will benefit the academic community including: development of a
The purpose of the Consortium on Sustainable and Alternative Fibers Initiative (SAFI) is to develop fundamental and applied research on the use of alternative and sustainable fibers for the manufacturing of market pulp, hygiene products and nonwovens. The idea for SAFI has grown out of societal needs for alternative yet sustainable materials. SAFI will study the potential of alternative fibers based on technical (performance), sustainable and economic principles.
The hygiene tissue industry (bath tissue and kitchen towel) is an annual 39 million tons - USD 100 billion - global market with a forecast to grow ~ 3% per year for the next decade [38], [39]. Most hygiene tissue paper grades require the use of both long and short virgin fibers, which provide strength and softness respectively [8]. As an effect of global megatrends, the demand for non-woody biomass for tissue manufacturing will continue to increase [40], and agricultural biomass, which is perceived to be a sustainable option, can be an important source of short fibers for the tissue industry [41]. Therefore, the need to research and create knowledge on the handling and conversion of biomass sorghum and switchgrass to produce sustainable and high-end fiber furnish for the hygiene tissue industry. The proposed feedstock can be established to supply fiber at industrial scale.
Led by the Department of Forest Biomaterials in collaboration with the Departments of Forestry, Business Management and Science Education at NC State University; this proposal will develop an educational program for a new generation of technology-to-commercialization researchers who will graduate with the expertise to perform risk analysis and develop risk management strategies across the value chain of biomass supply, biobased materials, and biofuels manufacturing to meet current and future national needs that will ultimately advance the nascent bioeconomy of the United States. Previous studies indicate that a limited number of companies in the forest product industry perform risk analysis for their decision-making process. We do believe that this small adoption rate is due to lack of awareness of the importance of risk analysis and risk management for effective/efficient R&D planning and investment and lack of expertise (people trained) to perform risk analysis across the whole supply chain. This proposal supports TESA in ����������������Agricultural Management and Economics���������������, in the discipline of Environmental Sciences/Management. Three Ph.D. students will be trained to analyze and propose mitigation strategies for current and future risks inherent to the bioeconomy. To considerably amplify the effect of this proposal, prospective fellows and project directors will deliver educational workshops in risk analysis and management targeting the biobased community across the U.S., while the proposal is expected to be completed in three years, project director expects to keep the program as a permanent teaching/research program. This proposed program supports USDA-NIFA Goal ����������������Catalyze exemplary and relevant research, education and extension programs���������������.
The objective of this project is to demonstrate catalytic processes for upgrading carbohydrates to hydrocarbon biofuels using two low-cost wet organic waste streams: Papermaking sludge and Post-sorted municipal solid waste. The work is based on the previous success of hydrocarbon production from corn stover in a bench scale via dilute-acid and enzymatic deconstruction followed by dehydration to furans, condensation, and hydrodeoxygenation to hydrocarbons. The project team will develop (1) a sugar production process and a removal strategy of non-carbohydrates that could poison catalysts during the conversion process, (2) isomerization and dehydration processes necessary to convert both glucose and xylose to furans in a single reactor, (3) an upgrading process of furans via aldol condensation with ketone and hydrodeoxygenation to diesel range hydrocarbons, and (4) a detailed techno-economic analysis to integrate and optimize the overall process. The developed process in this project will be demonstrated in a relevant pilot-scale and life cycle assessment will be evaluated.
The project will prepare a diverse group of college students and high school teachers with the knowledge and interdisciplinary tools necessary to advance the future of America������������������s bioenergy, bioproducts, and the bioeconomy. Distance courses will be developed and taught by faculty in the Departments of Forest Biomaterials & Environmental Resources, with guidance from the College of Education, undergraduate students are recruited from historically underserved institutions (HBCU, women������������������s college, community college), as are teachers from rural, high poverty NC high schools. Undergraduates will complete three of the five online courses in bioenergy & bioproducts, and complete an industry internship, and earn a certificate. Bioproducts and bioenergy industrial and research organization partners provide hands-on internship projects in the industry or in a research setting. Rural high school science teachers will complete three of the five online courses, earn a certificate, participate in professional development workshops, carry out lessons with their students during the school year, and conduct a career fair in bioproducts and bioenergy.