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Yuan Yao

Adjunct Assistant Professor

Biltmore Hall (Robertson Wing) 1022H


Date: 10/01/21 - 9/30/26
Amount: $9,999,146.00
Funding Agencies: National Science Foundation (NSF)

The Science and Technologies for Phosphorus Sustainability (STEPS) Center is a convergence research hub for addressing the fundamental challenges associated with phosphorus sustainability. The vision of STEPS is to develop new scientific and technological solutions to regulating, recovering and reusing phosphorus that can readily be adopted by society through fundamental research conducted by a broad, highly interdisciplinary team. Key outcomes include new atomic-level knowledge of phosphorus interactions with engineered and natural materials, new understanding of phosphorus mobility at industrial, farm, and landscape scales, and prioritization of best management practices and strategies drawn from diverse stakeholder perspectives. Ultimately, STEPS will provide new scientific understanding, enabling new technologies, and transformative improvements in phosphorus sustainability.

Date: 07/01/19 - 6/30/24
Amount: $161.00
Funding Agencies: National Science Foundation (NSF)

Biochar is a carbon-rich byproduct of thermochemical biomass conversions, and is closely linked to the Food-Energy-Water (FEW) nexus through its potential applications in wastewater treatment, agriculture management, and bioenergy, as well as indirect benefit in mitigating climate change. Although biochar has a potential to transform existing FEW nexus into more efficient and sustainable systems, it has not been widely implemented due to the lack of understandings in technical performance, economic feasibility, environmental impacts, and social implications of different combinations of biomass species, conversion technologies, and biochar applications. Such understanding is very hard to be obtained using traditional Life Cycle Assessment (LCA) or Techno-Economic Analysis (TEA) approaches due to intensive needs of process data and methodological limitations in integrating temporal, spatial, and socioeconomic dimensions. This project aims to address the knowledge gaps and methodological challenges by (1) using machine learning approaches to simulate and predict technical performance and life cycle inventory (LCI) of various combinations of biomass species, conversion technologies, process design, operational conditions, and applications of biochar; (2) building an integrated framework that seamlessly incorporate predictive LCA, TEA, Geographic Information System (GIS), and dynamic modeling to evaluate the environmental, economic, and social implications of biochar systems; (3) demonstrating the framework through real-world case studies in different geographic, temporal, and socioeconomic context.

Date: 10/01/20 - 12/31/23
Amount: $2,649,938.00
Funding Agencies: US Dept. of Energy (DOE) - Energy Efficiency & Renewable Energy (EERE)

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.

Date: 11/15/18 - 11/14/23
Amount: $238,500.00
Funding Agencies: US Dept. of Agriculture - National Institute of Food and Agriculture (USDA NIFA)

The objective of this proposal is to develop an education program for a new generation of researchers who understand the entire spectrum of biomass oligosaccharide production, animal production, and its analysis through a life cycle approach. Faculty members from two departments are proposing to create joint doctoral education program to address this Targeted Expertise Shortage Area (Animal Production) with Relevant Disciplines of (A) Animal Science, (B) Biotechnology, and (C) Renewable Natural Resources.Five focus areas are (1) Biomass oligosaccharide production; (2) Purification of xylose oligosaccharide; (3) Manufacturing and processing of animal feed; (4) Animal feeding and management; and (5) Life cycle Analysis. This program incorporates cross-disciplinary teamwork/advising, coursework in multiple disciplines, Preparing Future Leaders program, internship at a commercial farm, and exposure to biotechnology experts in industry.

Date: 10/01/18 - 9/30/23
Amount: $1,250,807.00
Funding Agencies: US Dept. of Energy (DOE) - Energy Efficiency & Renewable Energy (EERE)

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.

Date: 06/15/17 - 6/14/23
Amount: $2,750,000.00
Funding Agencies: US Dept. of Agriculture - National Institute of Food and Agriculture (USDA NIFA)

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.

Date: 10/01/19 - 12/31/22
Amount: $165,000.00
Funding Agencies: Environmental Research & Education Foundation

Abstract: The overall goal of the project is to develop systems to effectively utilize low-grade paper wastes in innovative, recognizable containerboard and pulp molded products in order to increase and stabilize the demand for low-grade paper waste products. This project will also evaluate the marketing potential of these new products. We will first evaluate the product performance of using low-grade paper wastes in containerboard and pulp molded product applications. A series of recycled products with varying concentrations of visible contaminants will be evaluated. We will then perform a sustainability evaluation on the new products. This would include environmental and economic evaluations. This will be followed by the evaluation of the desirability of having such products from the perspective of companies that utilize these containers to ship their products. This will be done through interviews/surveys of retail companies. We then will define the marketing advantages of these container products with respect to the general public, understanding the public’s level of preference for such containers and the ability of the container to develop strong positive brand identity with the public. This will be done through panel evaluations. We will then disseminate the results through peer-reviewed publications and conference presentations.

Date: 10/01/19 - 11/30/22
Amount: $1,067,772.00
Funding Agencies: US Dept. of Energy (DOE)

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.

Date: 11/01/17 - 6/30/21
Amount: $300,013.00
Funding Agencies: US Dept. of Agriculture (USDA) Forest Service

The project consists of a rigorous side-by-side comparison of CLT, steel, and concrete buildings considering the individual buildings and the integrated manufacturing and forestry system. It will involve a comprehensive, integrated study of the potential for CLT wood building to serve as a driver for: 1) Near-term carbon sequestration, and for providing other environmental benefits relative to alternative construction materials; 2) New opportunities for creating affordable housing for families and under-served communities; 3) Local and regional economic development associated with both the production of mass timber products, and new building construction; 4) New options for managing forests, that may allow forest land owners to economically thin overcrowded forest stands and remove standing dead and dying trees; and 5) Project results will be incorporated into a multi-attribute decision support tool to allow for the analysis of trade-offs, and used to focus the public discussion on the benefits and costs of the wide-scale deployment of CLT building systems.

Date: 09/01/18 - 2/28/21
Amount: $74,555.00
Funding Agencies: US Dept. of Commerce (DOC)

The overall goal of the project is to develop a systematic framework and reusable education modules to teach undergraduate and graduate students about various standards and standards-based analytical tools related to green buildings and sustainable materials. Modules will be integrated into existing courses in the College of Natural Resources and the College of Design at NCSU. We will focus on maximizing the replicability of those modules in both traditional classroom environments as well as online learning so that they can be adapted by universities nation-wide. Webinars and workshops in conferences will be offered to broaden the impacts and promote the modules. Real-world case studies will be critical parts of the modules and developed through the PI’s research projects and support from project collaborators.

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