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72 records · Page 4

Remaining Life Determination

This project developed and demonstrated the capability of nondestructive evaluation methods for detecting early stage fatigue damage in grey cast iron metal. Non-collinear ultrasonic wave mixing and laser speckle differentiation were the primary technologies evaluated on custom fatigue specimens having properties specified by Caterpillar, Inc. The ultrasonic method showed the greatest potential for estimating the remaining fatigue life in grey cast iron, which may provide remanufacturers with a level of confidence when fielding used component cores in high-stress applications. While successes were realized during this project, there are still follow-on research tasks required to prove the commercial applicability of the methods. The following report sections document the steps completed during the project and an assessment of the technologies applied.

36 MATERIALS SCIENCE↗

In-situ Nondestructive Evaluation of In-flight Particle Dynamics and Intrinsic Properties for Directed Energy Deposition

The objective of this exploratory project is to determine the feasibility of using laser diffraction, structured light 3D scanning, and x-ray diffraction for in-situ assessment and inspection of metal directed energy deposition (DED) that is applied to repair components such as engine parts in remanufacturing. During this project, we have successfully published or submitted at least one journal article for each subtask that we identified. One of our conference paper and presentation has won “best paper award” from Manufacturing & Design Division in the Institute of Industrial and Systems Engineers (IISE) Annual Conference 2021. Through this seed grant, we successfully validated the concepts and proved the three in-situ monitoring techniques work well to predict some defects generation during direct energy deposition. We submitted follow-up proposals to continue work on this topic.

36 MATERIALS SCIENCE↗

Non-Destructive In-Process Assessment of Thermal Spray Repairs

This exploratory project, entitled “Non-Destructive In-process Assessment of Thermal Spray Repairs,” evaluated the capabilities and limitations of four non-destructive testing (NDE) technologies for detection of defects in as-sprayed thermal spray coatings: acousto-ultrasonics, vibro-thermography, thermal wave infrared (IR) imaging, and flash IR thermography. The project goal was to identify a single technology suitable for use as an in-process inspection for two common classes of defects in thermal spray coatings, porosity and disbonds. Two rounds of test coupons were fabricated with intentionally seeded defects in AISI 420 stainless steel coatings deposited by twin wire arc (TWA) spray onto gray cast iron substrates. These standardized test coupons allowed the sensitivity of the four NDE methods to be directly compared. The results indicated that the acousto-ultrasonic method will not meet requirements for accuracy, inspection time, and reproducibility, while the vibrothermography method will not meet requirements for integration within remanufacturing cells and process flows. The IR methods, thermal wave imaging and flash thermography, both exhibited acceptable accuracy and reproducibility; however, the former method does not meet the requirement for inspection time. Flash IR thermography met all requirements in the initial round of testing, and that result was confirmed in a second round of testing on samples with a larger, more complex geometry. A final recommendation for further development of flash IR thermography was therefore made based upon i) detection performance, and ii) feasibility of deployment into the target application of resurfacing CAT engine blocks and headers.

36 MATERIALS SCIENCE↗

2023 Critical Materials Strategy

The global effort to curb carbon emissions is accelerating demand for clean energy technologies and the materials they rely on. Demand for these materials will only continue to grow, especially as some nations aim to achieve net zero emissions by 2050. While some major materials like steel, copper, and aluminum are already powering the fossil fuel economy, others are more minor materials with potential supply risks. These risks could jeopardize the ability to reduce greenhouse gas emissions within the desirable timeframe to avoid significant climate change. In some cases, it may be necessary to take action to improve the resilience of material supply chains and mitigate supply risks. Understanding the importance of individual materials to clean energy and the supply risks associated with them is necessary to identify which materials may serve as potential roadblocks to a clean energy future. The U.S. Department of Energy (DOE) issued a series of 13 supply chain deep dive assessment reports on various energy technologies in 2022 in response to President Biden’s Executive Order on America’s Supply Chains (E.O. 14017). These reports emphasized that supply chain bottlenecks can occur at any stage of the value chain from mining and refining to component and even sub-system manufacturing. The bottlenecks are a combination of factors such as material availability, equipment availability, work force availability and quality, logistics, regulatory framework, and market conditions. These bottlenecks were worsened during the global Covid-19 pandemic. Its lingering impacts have hindered capacity expansion for material supply chains and prevented product lead-time recovery. One approach to reduce supply chain risks for the United States is to have a strong domestic manufacturing sector with a diverse set of producers. Boosting responsible domestic production would require leveraging the latest science not only in material extraction but also in developing substitutes, recycling, reuse, and remanufacturing. This report is an updated analysis of previous Critical Materials Strategy (CMS) reports published by the DOE in 2010, 2011, and 2019 based on national and global priorities, technology advancement, and technology adoption trends. Like the CMS reports, this analysis presents the results of a formal material criticality assessment to identify which materials are critical to the continued deployment of clean energy technologies globally. The analysis in this report leveraged the DOE supply chain deep dive assessments to develop the initial list of materials to evaluate. This DOE Critical Materials Assessment (CMA) is conducted independently of criticality assessments performed by other U.S. government agencies, such as that conducted by the U.S. Geological Survey (USGS). This analysis complements the USGS critical minerals determination in three aspects. First, the DOE assessment is performed from a global perspective, while the USGS analysis focusses on the importance of minerals to the U.S. economy. Second, this report focuses on the importance of materials to clean energy technologies, rather than to the economy in general. Lastly, this study is forward looking to 2035 based on clean energy deployment scenarios, whereas the USGS assessment is retrospective. Materials evaluated in this report that do not appear in the USGS Critical Minerals List include copper, uranium, electrical steel, and SiC. A draft version of this report received ~80 public comments related to supporting data and methodological improvement. Those comments have been incorporated as much as possible where appropriate. Highlights of findings from this 2023 CMA include: Rare earth materials (neodymium, praseodymium, dysprosium, and terbium) used in magnets in electric vehicle (EV) motors and wind turbine generators continue to be critical. While dysprosium (Dy) and terbium (Tb) are both heavy rare earth elements that serve the same function in magnets, the criticality of Tb is slightly lower than that for Dy in the short term due to the widespread use of Dy in high-grade magnets and Tb’s present role as a substitute. Similarly, praseodymium (Pr) is critical in the medium term but only near critical in the short term because it is more substitutable in magnets than neodymium (Nd); Materials used in batteries for EVs and stationary storage are now considered to be critical. While cobalt (Co) was found to be critical in this and previous reports, lithium (Li) becomes critical in the medium term due to its broader use in various battery chemistries and the rampant growth of the EV industry. Natural graphite is a new addition in this assessment and is also found to be critical; Platinum group metals used in hydrogen electrolyzers, such as platinum (Pr) and iridium (Ir), are critical due to an increased focus on hydrogen technologies to achieve net zero carbon emissions, while those used in catalytic converters, such as rhodium (Rh) and palladium (Pd), were screened out due to the decreased importance of catalytic converters in the medium term; Gallium (Ga) continues to be critical due to its use in light-emitting diodes (LEDs). In addition, the use of Ga has increased in magnet manufacturing and in semiconductor in forms such as gallium arsenide (GaAs) or gallium nitride (GaN); Major materials like Aluminum (Al), copper (Cu), nickel (Ni), and silicon (Si) move from noncritical in the short term to near critical in the medium term due to their importance in electrification; Electrical steel is near critical due to its use in transformers for the grid and electric motors in EVs.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗

Development of a Sulfur Tolerant CHG Process (CRADA 442) (Final Report)

The Pacific Northwest Laboratory (PNNL) has developed the Catalytic Hydrothermal Gasification (CHG) technology, which can convert low-value organics dispersed in aqueous streams, such as the aqueous phase byproduct from hydrothermal liquefaction (HTL) of wet wastes, to a mixture of methane, H 2 , and CO 2 . The current CHG catalyst, ruthenium (Ru) on a graphite substrate, was selected for its effectiveness as a reducing catalyst. However, the target waste aqueous feedstock, the HTL aqueous phase from wet wastes, such as sewage sludge, contains a fair amount of sulfur in both organic and inorganic forms. Like many other reduced metal catalysts, Ru is deactivated or poisoned by exposure to sulfur, among other contaminants. In general, a deactivated Ru catalyst cannot be reactivated or restored except by removing and returning it for remanufacturing. Therefore, there is an urgent need for a sulfur-resistant catalyst to enable CHG processing of the HTL aqueous waste stream. PNNL, with support from SoCalGas CRADA, has developed a sulfur resistant CHG catalyst and demonstrated a stable CHG process for converting HTL aqueous phases from wet wastes. Here, we report the major accomplishments of the project: • We have demonstrated that sulfided Ru based catalysts is stable during CHG of HTL aqueous waste stream, with a requirement of activity improvement. • We have developed a new catalyst, with 0.5-2 wt.% Ru loading, showing better activity compared to the baseline 6.7 wt.% RuSx/C catalyst. • With the new catalysts, the single-pass COD reduction is approximately 60% and two-pass COD reduction can reach approximately 85%. • The process is robust in terms of being effective across a wide range of organic species in the feedstock. • Techno-economic analysis was conducted to evaluate the economic impact of catalyst advancement and identify further improvement requirements. This type of catalyst shows great potential to be efficient and robust for CHG with low catalyst cost.

03 NATURAL GAS↗

Infinitely Recyclable Network Polymers, Enabling Sustainable Manufacturing (CRADA Final Report)

This FLO Materials project was aimed at commercializing a new, infinitely recyclable material that can enable closed-loop lifecycles for hard-to-recycle plastics and plastic products. Four hundred million metric tons of virgin plastic is produced each year, yet less than 10% of this material is recycled. In the US alone, 2% of energy consumption is dedicated to the manufacture of virgin plastics, polymer resin, and synthetic rubbers. By keeping plastic materials in circulation longer, we can reduce waste, lower manufacturing costs, cut energy and oil consumption, and drastically reduce greenhouse gas (GHG) emissions. Specifically, FLO’s innovation overcomes the complications associated with salvaging difficult-to-recycle plastics (i.e., contaminated thermoplastic linear polymers, thermoset cross-linked network polymers), which represent at least 20% of total polymer global production, with a recycling rate of near 0%. Chemical recycling of these new polymers through depolymerization allows all additives to be easily removed at room temperature and the recovered monomers to be remanufactured into next generation materials with 100% recovery of mechanical performance and aesthetic quality.

36 MATERIALS SCIENCE↗

Recycling of PET by Dissolution-Purification-Recovery (DPR) Process Using Bioderived Solvent

Polyethylene terephthalate (PET) waste continues to accumulate at staggering rates, with the majority still routed to landfills due to limitations in current recycling methods. While mechanical recycling is widely implemented, it struggles to effectively remove colorants, additives, and harmful contaminants - resulting in discolored, degraded materials with limited reuse potential. In this presentation, we demonstrate a scalable dissolution-purification-recovery (DPR) process designed to selectively reclaim high-purity PET from post-consumer bottle flake. The method utilizes a food grade bio-based solvent for targeted PET dissolution, followed by activated carbon treatment for impurity removal and antisolvent-induced precipitation for polymer recovery. The resulting recycled PET exhibits complete decolorization, significantly reduced metal contamination, and minimal loss in molecular weight. These performance metrics indicate strong suitability for remanufacturing into new bottles, offering a circular alternative to traditional mechanical recycling pathways.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

A Circularity Assessment for Silicon Solar Panels Based on Dynamic Material Flow Analysis

Solar photovoltaics (PV) are the fastest growing renewable energy technology for clean, inexpensive, and sustainable electricity generation. Along with numerous technical roadmaps to improve system cost, performance and reliability, the PV industry should also plan to handle large volumes of silicon panel waste, which is initially estimated to be ~13 million metric tons (MT) by 2050 in the U.S. alone. Understanding the magnitude of material needs and how material flows throughout the PV panel life cycle could respond to design, operational and different end-of-life (EOL) circular pathways will help transition into a circular, resource-conserving economy. Herein, we introduce a dynamic material flow analysis (DMFA) framework based on electricity generation to quantify time-series stocks and flows of bulk PV materials (e.g., solar glass and aluminum frames) throughout the life cycles of utility-scale silicon PV systems in the U.S. in the period 2000-2100. We apply the model to a range of scenarios to understand how material demands depend on selected PV-related parameters, different material circularity strategies, and recent module design trends (e.g., bifacial, frameless). We found that float glass and aluminum in PV installations would likely reach 100 million MT and 12 million MT by 2100, respectively, in the baseline scenario. The most influential parameters for PV installation and subsequent waste reduction are found to be module lifetime, module efficiency, annual degradation, and material reduction. Module recycling and component remanufacturing were found to be the most effective material circularity strategies for waste minimization. Panel reuse has negligible savings on waste under current module efficiencies compared to replacements with newer generations with higher efficiency. Ongoing trends to produce larger power frameless modules could save 10 million MT of glass and ~9 million MT of aluminum. Our results enable advanced planning for future materials needs and provide insight into potential opportunities to minimize waste.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗

A Circularity Assessment for Silicon Solar Panels Based on Dynamic Material Flow Analysis: Preprint

Solar photovoltaics (PV) are the fastest growing renewable energy technology for clean, inexpensive, and sustainable electricity generation. Along with numerous technical roadmaps to improve system cost, performance and reliability, the PV industry should also plan to handle large volumes of silicon panel waste, which is initially estimated to be ~13 million metric tons (MT) by 2050 in the U.S. alone. Understanding the magnitude of material needs and how material flows throughout the PV panel life cycle could respond to design, operational and different end-of-life (EOL) circular pathways will help transition into a circular, resource-conserving economy. Herein, we introduce a dynamic material flow analysis (DMFA) framework based on electricity generation to quantify time-series stocks and flows of bulk PV materials (e.g., solar glass and aluminum frames) throughout the life cycles of utility-scale silicon PV systems in the U.S. in the period 2000-2100. We apply the model to a range of scenarios to understand how material demands depend on selected PV-related parameters, different material circularity strategies, and recent module design trends (e.g., bifacial, frameless). We found that float glass and aluminum in PV installations would likely reach 100 million MT and 12 million MT by 2100, respectively, in the baseline scenario. The most influential parameters for PV installation and subsequent waste reduction are found to be module lifetime, module efficiency, annual degradation, and material reduction. Module recycling and component remanufacturing were found to be the most effective material circularity strategies for waste minimization. Panel reuse has negligible savings on waste under current module efficiencies compared to replacements with newer generations with higher efficiency. Ongoing trends to produce larger power frameless modules could save 10 million MT of glass and ~9 million MT of aluminum. Our results enable advanced planning for future materials needs and provide insight into potential opportunities to minimize waste.

circular economy↗

Quantifying Energy Flows in PV Circularity Processes: Preprint

As sustainability and end-of-life management become a hot topic to timely address in the PV community, a proper evaluation of the benefits of circular pathways such as recycling, reuse, and remanufacturing has not been performed holistically beyond material flows or LCA analysis. Energy flows are critical for evaluating energy generation technologies. Previously they have been used to compare renewables to fossil generation and then between PV technologies. This paper brings energy flows to bear on reaching circular pathways for PV. The energy flows to track energy usage, generation, and losses complementary to the mass flows are presented for silicon through the leverage of the PV ICE framework.

circular economy↗

Enabling Recycling of Composites: Understanding the Impacts of Multiple Thermal Processing Cycles

When considering the utilization of recycled short carbon fiber feedstock materials for advanced manufacturing, understanding the material degradation behavior is essential in determining how many times a composite material can be effectively reprocessed and remanufactured. This study characterizes the degradation behavior of short carbon fiber acrylonitrile butadiene (CF-ABS) that has been reprocessed five times with twin screw extrusion. Parallel plate rheology was completed to observe the degradation in complex viscosity of the recycled feedstock materials. Gel permeation chromatography (GPC) was utilized to characterize the changes in molecular weight distribution of the recycled materials as a result of thermal and mechanical degradation during the re-processing steps. Rheological characterization, GPC, and twin-screw processing data help inform the process optimizations required to process the recycled feedstock material. Successful characterization of the degradation behavior of short fiber composite feedstock materials aids in increased understanding of the lifespan of high value carbon fiber composite materials and aids in process optimization of recycled composite materials.

Walker, Roo↗

Wind Turbine Blade Repurposing and Recycling: Coupling Repurposing Methods with 3D Printing Technology

Fiber-reinforced thermoplastic composites continue to be implemented in several marketsbecause of their strength capacity and light weight. Especially in the wind industry, wind bladesare made of this material which makes them ideal for wind energy generation, but bladesbecome a problem at end-of-life. Because recycling thermoplastic composites technologiesare still not cost and environmentally effective, research in this space is needed. This paperpresents a case study for coupling repurposed wind turbine blades and 3D printing technology.The purpose is to remanufacture decommissioned wind blades into bus stop roof and seatingsections to then use recycled glass fiber from a decommissioned wind turbine blade to 3Dprint structural and/or fixtures needed in the assembly. We provide an overview of the designprocess, and the development process steps in repurposing and 3D printing the material,delving into key parameters required for a successful implementation.

Henao, Yulizza↗

Anode Upcycling via Tailored Solvent Treatment

To achieve a truly closed-loop direct recycling process for lithium-ion batteries, all component materials must be recovered. To date, direct recycling method development has primarily focused on the high-value transition-metal cathode materials, while the inherently lower-value graphite has been challenging to recover in a cost-effective manner. However, end-of-life graphite contains a unique engineered value due to the presence of the solid electrolyte interphase (SEI). Growth of the SEI during the cell's active lifetime stabilizes the electronically reactive graphite surface through an irreversible consumption of Li, and thus necessitates both excess lithiation of the cathode and a costly and time-intensive formation procedure during manufacturing. An optimized pre-formed SEI that capitalizes on existing SEI components from end-of-life batteries has the potential to significantly reduce cathode lithiation requirements and eliminate the critical bottleneck of formation cycling during cell remanufacturing. Further, retaining Li at the anode obviates the need for a separate Li leaching and recovery step, improving the overall efficiency of the direct recycling line. In this work, we present a novel approach to "upcycling" spent graphite through use of tailored chemical treatment to remove adverse (i.e., highly resistive and/or poorly passivating) SEI species while retaining beneficially passivating components. We have explored a rational set of solvents spanning a range of polarity, proticity, and molecular size to evaluate structure-property-performance relationships between applied solvent(s), removed and remaining SEI species, and electrochemical response of the resulting graphite product. Further, we have developed and optimized a robust and holistic analysis procedure that couples symmetric-cell electrochemical testing, multi-modal materials characterization, and advanced electrochemical modeling. These analysis results inform a set of correlative metrics for graphite performance relative to both solvent properties and upcycled SEI composition. We demonstrate effective tunability in the residual SEI composition by varying solvent identity and concentration, and report on several promising solvent systems that achieve comparable or performance to pristine graphite.

anode recycling↗

Recycling of additively printed anisotropic Nd-Fe-B bonded magnets

A high potential cost-effective and environmentally friendly method has been applied for recycling anisotropic Nd-Fe-B bonded magnets. Waste additively printed Hydrogenation-Disproportionation-Desorption-Recombination (HDDR) Nd-Fe-B anisotropic bonded magnet was pulverized into composite powder containing Nd-Fe-B particles and nylon binder through cryomilling at a liquid nitrogen temperature (~77 K) under Ar inert atmosphere. Then, the cryomilled composite powder was warm compacted into a bonded magnet. Further, the magnetic particles were aligned during post-compaction annealing under a magnetic field of 30 kOe. The recycled bonded magnets have a higher density (3% enhancement), but slightly inferior magnetic properties compared to the original magnets, i.e., the magnetic remanence, coercivity and maximum energy product are reduced by 2%, 3% and 8%, respectively. The scanning electron microscopy revealed that some HDDR Nd-Fe-B powder crumbled into fine particles during cryomilling. Powder X-ray diffraction showed a small amount of Nd-oxide impurity in the cryomilled powder. The slightly deteriorated magnetic properties are ascribed to the oxidation of Nd-Fe-B particles due to formation of fresh fracture surface during cryomilling. The approach enables the direct reuse of end-of-life bonded magnets in an economical and environmentally friendly way.

36 MATERIALS SCIENCE↗

Prioritizing circular economy strategies for sustainable PV deployment at the TW scale

Global decarbonization requires an unprecedented scale-up of photovoltaic (PV) manufacturing and deployment. The material demand and eventual end of life management associated with multi-TW scale deployment poses many challenges. Circular Economy (CE) and it's associated R-Actions (Reduce, Reuse, Recycle) have been proposed to mitigate end of life management and material sourcing concerns. However, CE metrics typically focus on a single product and only consider mass, excluding energy flows. This work leverages the PV in Circular Economy (PV ICE) tool to quantify the deployment, mass, and energy impacts of R-Actions and proposed sustainable PV designs in the context of achieving energy transition deployment goals (75 TW in 2050). 13 module scenarios are established and evaluated across 6 capacity, mass and energy metrics to identify tradeoffs and priorities. We find that increasing module efficiency can reduce near-term material demands up to 30% and improve energy metrics by up to 9%. Material circularity (recycling) can minimize lifecycle wastes and reduce material demands at the cost of higher energy demands. Increasing module lifetime, including reliability improvements and reuse strategies, is effective at reducing both material (>10%) and energy demands (24%). Uniquely, lifetime improvements maximize benefits and minimize the harms across all six metrics while achieving multi-TW scale deployment.

Photovoltaics↗

A Machine Learning–Based Tire Life Prediction Framework for Increasing Life of Commercial Vehicle Tires

In the commercial freight industry, tire retreading decisions are often conservative due to limited knowledge of a tire’s remaining service life. This practice leads to increased costs and material waste. This paper proposes a machine learning–based approach for estimating tire casing life and retreadability, focusing on usage data rather than wear information. This approach could extend the tire’s lifespan and reduce landfill waste. Data integration from diverse tire casing measurement sources presents challenges, including imbalanced removal data. Our methodology addresses these challenges by using historical inspection, telematics, and finite element modeling (FEM) datasets. We introduce “Tire Casing Energy” as a comprehensive usage input and apply a Variance-Reduction Synthetic Minority Oversampling Technique (VR-SMOTE) for data imbalance rectification. A random forest model is used to estimate the state of the tire casing and the casing removal probability, with Bayesian optimization applied for hyperparameter tuning, enhancing model accuracy. Here, the proposed prediction framework is able to differentiate different truck fleets and tire locations based on their usage parameters. With the aid of this machine learning model, the importance and sensitivity of different tire usage parameters can be obtained, which is beneficial to maximize tire life.

Data balancing↗

More Than Recycling: How Should We Define Circularity Goals for PV in a Global Energy Transition? Preprint

Energy transition to carbon-free electricity is a crucial pillar of the Circular Economy. Renewable energy reduces environmental impacts and decarbonizes the production of other goods. But, manufacturing renewable energy sources, such as photovoltaic (PV) modules, require energy inputs that are currently carbon intensive. So, how do we decarbonize and circularize these critical technologies to achieve a sustainable energy transition? This work proposes that effective capacity-the installed capacity accounting for degradation rates and failures-is a critical metric to evaluate renewable energy technologies on the path toward circular economy and energy transitions. Our analyses also emphasize the importance of examining a suite of metrics incorporating mass and energy flows to identify potential tradeoffs and inform design or lifecycle management decisions holistically.

bifacial↗

More Than Recycling: The Importance of Multiple Metrics for a Circular Economy for PV in the Energy Transition

Energy transition to carbon-free electricity is a crucial pillar of the Circular Economy. Renewable energy reduces environmental impacts and decarbonizes the production of other goods. But, manufacturing renewable energy sources, such as photovoltaic (PV) modules, require energy inputs that are currently carbon intensive. So, how do we decarbonize and circularize these critical technologies to achieve a sustainable energy transition? This work proposes that effective capacity-the installed capacity accounting for degradation rates and failures-is a critical metric to evaluate renewable energy technologies on the path toward circular economy and energy transitions. Our analyses also emphasize the importance of examining a suite of metrics incorporating mass and energy flows to identify potential tradeoffs and inform design or lifecycle management decisions holistically.

bifacial↗