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NASA NTRS1980

Orbit transfer vehicle engine study. Volume 2: Technical report

The orbit transfer vehicle (OTV) engine study provided parametric performance, engine programmatic, and cost data on the complete propulsive spectrum that is available for a variety of high energy, space maneuvering missions. Candidate OTV engines from the near term RL 10 (and its derivatives) to advanced high performance expander and staged combustion cycle engines were examined. The RL 10/RL 10 derivative performance, cost and schedule data were updated and provisions defined which would be necessary to accommodate extended low thrust operation. Parametric performance, weight, envelope, and cost data were generated for advanced expander and staged combustion OTV engine concepts. A prepoint design study was conducted to optimize thrust chamber geometry and cooling, engine cycle variations, and controls for an advanced expander engine. Operation at low thrust was defined for the advanced expander engine and the feasibility and design impact of kitting was investigated. An analysis of crew safety and mission reliability was conducted for both the staged combustion and advanced expander OTV engine candidates.

Source record↗
DOE OSTI2020

Workshop Report for Next-Gen AI for Proliferation Detection: Accelerating the Development and Use of Explainability Methods to Design AI Systems Suitable for Nonproliferation Mission Applications

Artificial intelligence (AI) promises powerful new capabilities in an expansive array of applications. One area is proliferation detection, where AI can provide transformative tools to achieve objectives currently inaccessible using conventional methods. In particular, AI affords the opportunity to use new indicators and process massive amounts of heterogeneous data that can increase sensitivity to proliferant activities and push proliferation detection to the earliest possible stages. However, existing AI tools are not ready to achieve such potential, falling short in regard to some important considerations involved in proliferation detection. One crucial aspect that requires improvement is the explainability of the most powerful AI algorithms (i.e., understanding how the algorithms actually arrive at their conclusions)-the lack of which prevents widespread adoption in national security missions. The Data Science and AI portfolio within the National Nuclear Security Administration's Office of Defense Nuclear Nonproliferation Research and Development is driving the development of next-generation AI for proliferation detection through the expertise and work of the national laboratories and partners in academia. The "Next-Gen AI for Proliferation Detection: Accelerating the Development and Use of Explainability Methods to Design AI Systems Suitable for Nonproliferation Mission Applications" workshop aimed to further this objective. The meeting was held virtually on Sept. 15-16, 2020 and included more than 170 participants, primarily from the national laboratories with additional contributions from university researchers and mission partners. Each day included a keynote presentation, four technical presentations about cutting-edge research in explainability, and a panel to explore considerations in applying explainability and developing AI systems that can accelerate the transition of emerging AI technologies among partners and end users to solve critical mission questions. This report summarizes the Next-Gen AI for Proliferation Detection workshop's content and findings.

98 NUCLEAR DISARMAMENT, SAFEGUARDS, AND PHYSICAL P↗
DOE OSTI2017

Benefits of digitalizing and employing simulation to increase plant system performance and ensure compliance with technical specifications - 109

The essential services water system in a BWR nuclear power plant was affected by corrosion, soiling and blockages due to ageing. Those episodes affected safety margins hindering the Technical Specifications compliance during periodic system testing. Tecnatom designed, implemented and tested a design modification for the on-line monitoring of this system by integrating it in the existing Digital Control System (DCS). Key system parameters were acquired in real time to be displayed in the Human System Interface, used in performing calculations and stored their historical evolution. The objective was to optimize monitoring and surveillance of the essential service water system. Furthermore, Tecnatom developed an engineering simulator ('What if' simulator) consisting of a hydraulic model of the system. This simulator takes as inputs each heat exchanger performance parameters from the plant DCS, allows the user to change the essential services water system configuration (valves position, UHS level...) and calculates theoretical process values predicting the system real behavior. In a second stage, more system instruments were wired to the DCS for Technical Specifications compliance automatic surveillance regarding opening and closing times of system valves. Operating experience shows important benefits after the digitalization. It enhances on-line information of system operation and automates calculation of load loss factor of each heat exchanger. It eases the evaluation of blockages and soiling in the system allowing optimization of cleaning proceedings. System Surveillance Requirements and Test Requirements reports have been automated optimizing the operation workload. The simulator use enables to identify optimal system configuration increasing safety margins of the system and ensuring Technical Specifications fulfillment. (authors)

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗
DOE OSTI2023

Development of Advanced Solid Sorbents for Direct Air Capture (Final Report)

RTI International is partnering with Creare, and Mohammed VI Polytechnic University (UM6P) successfully met all major technical objectives as outlined below: Identified one MOF adsorbent for DAC; Identified one amine-P-dendrimer adsorbent for DAC; Performed Computational fluid dynamics simulations of the MOF and amine-P-dendrimer adsorbents and validate them with experimental data; Selected one adsorbent for DAC; Demonstrated the scale-up of selected candidate and perform cost review; Performed a preliminary process design; Performed technology maturation plan and environmental health and safety risk assessment. After a thorough comparison between both adsorbents (MOFs and P-dendrimers) and based on their technical merits, the amine-based P-dendrimers sorbent was selected as the best performing adsorbent for DAC. In fact, the amine-based P-dendrimers have demonstrated superior performance over the MOF sorbents under relevant DAC conditions. The selected sorbent has been used in subsequent projects (DE-FE0032099 and DE-AR0001412) and has demonstrated similar superior performance with no loss of activity after long-term sorption-desorption testing (e.g., 100 cycles). This sorbent has demonstrated a very high and stable sorption performance, excellent kinetics, and fast regeneration at 80 °C, specifically at 75% relative humidity (RH). The incorporation of RTI’s high-performance, high-durability amine-based P-dendrimers sorbent and Creare’s hybrid additive manufacturing (H-AM) technology that will produce high performance, compact heat and mass exchange structures at low cost using methods, will lead to a contactor that is optimized for wind-driven operation. This contactor technology provides a technically viable pathway for reducing the cost of DAC to <$100/tonne of CO 2 .

36 MATERIALS SCIENCE↗
DOE OSTI2013

MR-Guided High-Intensity Focused Ultrasound Ablation of Breast Cancer with a Dedicated Breast Platform

Optimizing the treatment of breast cancer remains a major topic of interest. In current clinical practice, breast-conserving therapy is the standard of care for patients with localized breast cancer. Technological developments have fueled interest in less invasive breast cancer treatment. Magnetic resonance-guided high-intensity focused ultrasound (MR-HIFU) is a completely noninvasive ablation technique. Focused beams of ultrasound are used for ablation of the target lesion without disrupting the skin and subcutaneous tissues in the beam path. MRI is an excellent imaging method for tumor targeting, treatment monitoring, and evaluation of treatment results. The combination of HIFU and MR imaging offers an opportunity for image-guided ablation of breast cancer. Previous studies of MR-HIFU in breast cancer patients reported a limited efficacy, which hampered the clinical translation of this technique. These prior studies were performed without an MR-HIFU system specifically developed for breast cancer treatment. In this article, a novel and dedicated MR-HIFU breast platform is presented. This system has been designed for safe and effective MR-HIFU ablation of breast cancer. Furthermore, both clinical and technical challenges are discussed, which have to be solved before MR-HIFU ablation of breast cancer can be implemented in routine clinical practice.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2013

Blackbody comparator for thermocouple calibration

MIKES is developing a measurement set-up for calibrating thermocouples in the temperature range 960 °C - 1500 °C. The calibration method is based on direct comparison of thermocouples and radiation thermometers. We have designed a graphite blackbody comparator cell, which is operated in a horizontal single-zone tube furnace. The cell includes two blackbody cavities for radiation temperature measurements. The cavities have openings on opposite sides of the cell, allowing simultaneous measurement with two radiation thermometers. The design of the comparator allows three thermocouples to be calibrated simultaneously. The thermocouples to be calibrated are inserted in thermometer wells around one of the measurement cavities. We characterize the blackbody comparator in terms of repeatability, temperature distribution and emissivity. Finally, we validate the uncertainty analysis by comparing calibration results obtained for type B and S thermocouples to the calibration results reported by Technical Research Institute of Sweden (SP), and MIKES. The agreement in the temperature range 1000 °C - 1500 °C is within 0.90 °C, the average deviation being 0.17 °C.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2018

Alternate Design Concepts for the High Flux Isotope Reactor using Low-Enriched Uranium Fuel Systems: Scoping Analysis

The Oak Ridge National Laboratory (ORNL) High Flux Isotope Reactor (HFIR) is a multi-mission research reactor dedicated mainly to isotope production, neutron scattering experiments, material irradiation, testing and activation. In the framework of non-proliferation policies, the international community is currently aiming to reduce or even eliminate, when and where possible, the use of Highly Enriched Uranium (HEU: 235 U/U ≥ 20 wt. %) in civilian applications. In that context, most research reactors worldwide still operating with HEU fuel are actively engaged in an effort to convert to Low Enriched Uranium fuel system (LEU: 235 U/U < 20 wt. %). Within the US, the High Performance Research Reactor (USHPRR) fleet (which includes HFIR) is expected to convert to LEU fuel using the UMo “monolithic” fuel system currently under development. ORNL is responsible for the development of a LEU design for HFIR. In the past years, Argonne National Laboratory (ANL) offered technical assistance to the ORNL LEU design team whenever deemed appropriate. Due to their complex nature, acceptable HFIR LEU designs identified so far, all based on the UMo monolithic fuel system, would require a substantial fabrication development effort before being proven commercially viable. In order to mitigate technical risks and reduce cost/schedule uncertainties, it appears appropriate to study alternate design solutions and alternate fuel systems as possible backup options for the HFIR conversion to LEU fuel. In that context, ANL has been exploring alternate design concepts for HFIR. Complementing the ORNL design activities, the goal is to find the best design solution for HFIR in term of cost, performance and safety. The present report summarizes the findings regarding two types of alternate conceptual design: U 3 Si 2 designs and un-contoured UMo design. Based on available tools and methods, preliminary analysis show that both concepts could probably meet performance and steady-state safety requirements but element fabrication would remain complex and would require a non-trivial fabrication development effort.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗
DOE OSTI2020

Review of the Technical Basis for Properties and Fuel Performance Data Used in HEU to LEU Conversion Analysis for U-10Mo Monolithic Alloy Fuel

This report provides the technical basis for properties and fuel performance data used in conversion analysis for U.S. High Performance Research Reactors (USHPRR) that will convert from highly enriched uranium (HEU) to low-enriched uranium (LEU) using a new U-10Mo monolithic alloy fuel that is being qualified. The conditions that the fuel experiences changes between an HEU and LEU fuel element design due to many causes, including the density of the fuel, the presence of U-238 resonant absorber, changes to the plate and coolant channel dimensions, and changes in fuel management due to reactivity or optimization. These types of changes have been documented in operational and safety analyses conducted for conversions over decades for over 70 reactors. These conversions have all, or almost all, required recalculation of safety-related values as well as establishing operational characteristics of the core, including power distribution, reactor core power level, and cycle length between required fuel management. An overall objective of conversion is to change the reactor core design as little as possible while maintaining the reactors’ scientific, isotope production, medical, and engineering missions.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
NASA NTRS2012

Lessons Learned from Ares I Upper Stage Structures and Thermal Design

The Ares 1 Upper Stage was part of the vehicle intended to succeed the Space Shuttle as the United States manned spaceflight vehicle. Although the Upper Stage project was cancelled, there were many lessons learned that are applicable to future vehicle design. Lessons learned that are briefly detailed in this Technical Memorandum are for specific technical areas such as tank design, common bulkhead design, thrust oscillation, control of flight and slosh loads, purge and hazardous gas system. In addition, lessons learned from a systems engineering and vehicle integration perspective are also included, such as computer aided design and engineering, scheduling, and data management. The need for detailed systems engineering in the early stages of a project is emphasized throughout this report. The intent is that future projects will be able to apply these lessons learned to keep costs down, schedules brief, and deliver products that perform to the expectations of their customers.

Ahmed, Rafiq↗
NASA NTRS2012

Experimental Investigation of a Direct-drive Hall Thruster and Solar Array System at Power Levels up to 10 kW

As NASA considers future exploration missions, high-power solar-electric propulsion (SEP) plays a prominent role in achieving many mission goals. Studies of high-power SEP systems (i.e. tens to hundreds of kilowatts) suggest that significant mass savings may be realized by implementing a direct-drive power system, so NASA recently established the National Direct-Drive Testbed to examine technical issues identified by previous investigations. The testbed includes a 12-kW solar array and power control station designed to power single and multiple Hall thrusters over a wide range of voltages and currents. In this paper, single Hall thruster operation directly from solar array output at discharge voltages of 200 to 450 V and discharge powers of 1 to 10 kW is reported. Hall thruster control and operation is shown to be simple and no different than for operation on conventional power supplies. Thruster and power system electrical oscillations were investigated over a large range of operating conditions and with different filter capacitances. Thruster oscillations were the same as for conventional power supplies, did not adversely affect solar array operation, and were independent of filter capacitance from 8 to 80 ?F. Solar array current and voltage oscillations were very small compared to their mean values and showed a modest dependence on capacitor size. No instabilities or anomalous behavior were observed in the thruster or power system at any operating condition investigated, including near and at the array peak power point. Thruster startup using the anode propellant flow as the power 'switch' was shown to be simple and reliable with system transients mitigated by the proper selection of filter capacitance size. Shutdown via cutoff of propellant flow was also demonstrated. A simple electrical circuit model was developed and is shown to have good agreement with the experimental data.

Snyder, John S.↗
DOE OSTI2012

CW Room Temperature Re-Buncher for the Project X Front End

At Fermilab there is a plan to construct the Project X Injector Experiment (PXIE) facility - a prototype of the front end of the Project X, a multi-MW proton source based on superconducting linac. The construction and successful operations of this facility will validate the concept for the Project X front end, thereby minimizing the primary technical risk element within the Project. The room temperature front end of the linac contains an ion source, an RFQ accelerator and a Medium Energy Beam Transport (MEBT) section comprising a high bandwidth bunch selective chopper. The MEBT length is about 10 m, so three re-bunching CW cavities are used to support the beam longitudinal dynamics. The paper reports a RF design of the re-bunchers along with preliminary beam dynamic and thermal analysis of the cavities.

43 PARTICLE ACCELERATORS↗
DOE OSTI2017

High Temperature Reactor Research and Development Roadmap, Draft for Public Comment

Nuclear power provides clean, reliable energy, contributing about 20 percent of the electricity generated in the United States. It supplies approximately 60 percent of our non-greenhouse-gas emitting power, making it our nation’s single largest contributor of carbon-free electricity. This vital component of the U.S. energy portfolio avoids hundreds of millions of tons of carbon dioxide emissions each year and supports hundreds of thousands of U.S. jobs, and yet is facing unprecedented challenges. Complex market factors, falling alternative generation costs and lower electricity demand forecasts have made operating nuclear power plants uneconomical in some parts of the country. The industry is confronting premature shut downs, a lack of new plants in the pipeline, profound market challenges and intense financing requirements. However, none of these challenges reflect a reduced need for this reliable and clean source of baseload power. Our nation’s nuclear sector urgently needs to adjust to these challenges to ensure continued availability of this vital national energy resource. The Department of Energy and its national laboratories are aggressively working to revive, revitalize, and expand U.S. nuclear energy capacity. We are advancing nuclear energy technologies through targeted early-stage investments to ensure a strong domestic industry now and into the future. By leveraging public-private partnerships and the national laboratory system, we are developing an advanced nuclear infrastructure, encouraging a resilient supply chain, and promoting a strong nuclear pipeline. A key element of this effort is to support the recent and rapid expansion in innovative advanced reactor development already being led by the U.S. nuclear industry. Advanced reactors, particularly non-light water reactor concepts, offer the potential for significant improvements to safety, economics and environmental performance, to help sustain and expand the availability of nuclear power as a clean, reliable and secure power source for our nation. As part of this strategy, the Department of Energy commissioned the development of technology roadmaps for advanced non-light-water reactor concepts. The starting point for the roadmaps is the technical readiness assessment performed as part of an advanced test and demonstration reactor study released in 2016 [ ]. The roadmaps show the Research and Development (R&D) needed to support demonstration of advanced reactor concepts, for either engineering demonstration or commercial demonstration depending on concept maturity, by 2035. The starting point for the roadmaps is the technical readiness assessment performed as part of an advanced test and demonstration reactor study released in 2016. The roadmaps were developed based on a review of technical reports and vendor literature summarizing the technical maturity of each concept and the outstanding R&D needs. Tasks for specific systems were highlighted on the basis of time and resources needed to complete the tasks and the importance of the system to the performance of the reactor concept. The roadmaps are intended to be generic (i.e., not specific to a particular vendor’s design); however, features of the General Atomics Energy Multiplier Module were included to provide specific examples for illuminating needed R&D tasks to be conducted in support of demonstration in the near future.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2020

Community Solar for the Southeast (Final Report)

The Community Solar for the Southeast project provided technical assistance for cooperative and municipal utilities in the southeastern United States that are considering community solar programs. The project provided generally applicable information for these utilities in the form of an implementation guide and other freely available materials. It also provided detailed technical assistance to specific utilities in the form of feasibility analyses for possible community-scale solar (and energy storage) projects and program designs for community solar programs, all at no direct cost to the utilities. By helping to spur development of community solar projects in a region that historically had not seen much community-scale solar development, the program provided proof-of-concept for other community solar projects in the region, and helped to open up a market segment (cooperative and municipal utilities) that may have otherwise lacked the resources to independently pursue community solar development. The overall goal of the project was an expansion of community solar capacity at municipal and cooperative utilities in the southeastern United States (in this case meaning Virginia, North Carolina, South Carolina, Georgia, Florida, Kentucky, Tennessee, Alabama, and Mississippi). The specific target was to spur the development of community solar at these utilities throughout the Southeast such that at least 200 MW of community-scale solar would be developed by 2020. In order to reach this goal the project team first aimed to develop useful materials and conduct outreach with utilities and other relevant stakeholders. The team then conducted technical assistance projects to help individual utilities evaluate and, in several cases, pursue development of projects. The team conducted nine technical assistance projects in total: five in North Carolina, two in Virginia, one in Georgia, and one in Kentucky. The team also responded to smaller scale information requests from southeastern utilities throughout the project period.

14 SOLAR ENERGY↗
NASA NTRS2012

U.S. Spacesuit Knowledge Capture Series Catalog

The National Aeronautics and Space Administration (NASA) and other organizations have been performing U.S. Spacesuit Knowledge Capture (USSKC) since the beginning of space exploration through published reports, conference presentations, specialized seminars, and classes instructed by veterans in the field. The close physical interaction between spacesuit systems and human beings makes them among the most personally evocative pieces of space hardware. Consequently, spacesuit systems have required nearly constant engineering refinements to do their jobs without impinging on human activity. Since 2008, spacesuit knowledge capture has occurred through video recording, engaging both current and former specialists presenting technical scope specifically to educate individuals and preserve knowledge. These archives of spacesuit legacy reflect its rich history and will provide knowledge that will enhance the chances for the success of future and more ambitious spacesuit system programs. The scope and topics of USSKC have included lessons learned in spacesuit technology; experience from the Gemini, Apollo, Skylab, and Shuttle Programs; the process of hardware certification, design, development, and other program components; spacesuit evolution and experience; failure analysis and resolution; and aspects of program management. USSKC activities have progressed to a level where NASA, the National Air and Space Museum (NASM), Hamilton Sundstrand (HS) and the spacesuit community are now working together to provide a comprehensive way to organize and archive intra-agency information related to the development of spacesuit systems. These video recordings are currently being reviewed for public release using NASA export control processes. After a decision is made for either public or non-public release (internal NASA only), the videos and presentations will be available through the NASA Johnson Space Center Engineering Directorate (EA) Engineering Academy, the NASA Technical Reports Server (NTRS), the NASA Aeronautics & Space Database (NA&SD), or NASA YouTube. Event availability is duly noted in this catalog.

Bitterly, Rose↗
DOE OSTI2017

Final Technical Report: Targeting DOE-Relevant Ions with Supramolecular Strategies, DE-SC0010555

The effectiveness of three popular supramolecular strategies to selectively target negatively charged ions (anions) was evaluated. Ions of interest included oxo anions, particularly sulfate, that hamper nuclear waste remediation. Three objectives were pursued using a simple building block strategies and by strategically placing anion-binding sites at appropriate positions on organic host molecules. The goal of the first objective was to assess the influence of secondary, tertiary and quaternized amines on binding tetrahedral anions using mixed amide/amine macrocyclic and urea/amine hosts containing aromatic or heteroaromatic spacers. Objective 2 focused on the design of ion pair hosts, using mixed macrocyclic anion hosts joined through polyether linkages. Objective 3 was to explore the synthesis of new metal-linked extended macrocyclic frameworks to leverage anion binding. Key findings were that smaller 24-membered macrocycles provided the most complementary binding for sulfate ion and mixed urea/amine chelates showed enhanced binding over amide corollaries in addition to being highly selective for SO 4 2- in the presence of small quantities of water. In addition to obtaining prototype metal-linked macrocyclic anion hosts, a new dipincer ligand was designed that can be used to link macrocyclic or other supramolecular hosts in extended frameworks. When the tetraamide-based pincers are bound to two metal ions, an interesting phenomenon occurs. Upon deprotonation of the amides, two new protons appear between adjacent carbonyl pairs on the ligand, which may modify the chemistry, and metal-metal interactions in the complexes. Gel formation occurred for some of these extended hosts, and the physical properties are currently under investigation. The new tetracarboxamide-based pincers can also provide basic frameworks for double macrocycles capable of binding ion pairs as well as for binding metal ions and exploring intermetallic interactions through the pyrazine π system. Additionally appendages capable of influencing solvation effects can be introduced, and a number of other potential applications can be realized in areas such as soft materials chemistry, catalysis, sensing, and proton switches, the latter for binding and release of targeted guests. These findings provide a better foundation for understanding the selective binding of anions by targeted placement of hydrogen binding sites, and the strengths and weaknesses of various functional groups, that will allow for more the design of more effective anion sequestering agents. Our design strategy also used simple, cost-effective building blocks for host synthesis to allow for scale-up should real-world applications be forthcoming.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2019

Phase I Final Technical Report

Two subscale coils of Bi-2212 wire have been made and tested in a DOE 2018 STTR collaboration between Cryomagnetics and the Applied Superconductivity Center at Florida State University. These coils are used to test the feasibility of using small-diameter wire in a solenoidal configuration where single strand wire performance is crucial. If successful, the implementation of small-diameter wire into high field Bi-2212 HTS solenoids will allow for high J_E operation with moderate currents, making feasible the use of more modest control equipment, power supplies, and current leads. Furthermore, lower operating currents may allow series-connected design configurations with LTS background magnets, allowing for better, simpler, and more effective quench protection methods. A 25-Tesla magnet design, consisting of an 8-Tesla Bi-2212 coil with a 17-Tesla LTS coil, is fully underway at Cryomagnetics, and considerations of critical current, hoop stress, and quench protection will all be fully addressed. This document reports our findings up to this point, the end of the Phase I period.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Final Technical Report

The Department of Energy is interested in technologies that support the sustainable production of fuels, chemicals, and other bioproducts from plant biomass, to offset the nation’s reliance on fossil resources. The plant cell wall of energy crops provides the largest reservoir of raw materials for bioproducts. However, the widespread use of plant cell walls is hampered by their complexity and resistance to breakdown. To improve the productivity and cost-effectiveness of using energy crops to generate bioproducts, the fundamental problem of deconstructing plant cell walls must be addressed. This project developed and evaluated an innovative genetic modification technology to produce strategically designed enzymes that specifically accumulate in the plant cell wall. The resulting enzyme-engineered energy crops are expected to grow normally under natural conditions but break down more quickly and easily under high temperature during the production of biobased products. As such, this plant cell wall targeting enzyme engineering effort will reduce the cost of plant cell wall deconstruction and ultimately improve the economics of bioproducts. The overall objective of this project is to develop and evaluate the in-planta enzyme engineering technology to reduce lignocellulose deconstruction cost. The concept was first validated using tobacco plant, a model plant system that is typically used in lab testing for initial concept validation. Then the enzyme optimization was validated using switchgrass, the energy crop to be used to produce bioproducts. There are three specific objectives in this Phase I project: (1) validate the enzyme optimization concept using tobacco plant, a model plant system. (2) validate the enzyme optimization concept using switchgrass. (3) techno-economic analysis (TEA) for further scale-up application. By the end of this project, in-planta enzyme engineering was validated in both tobacco and switchgrass plants, with improved enzyme activity and saccharification efficiency. The in-planta enzyme engineering in Tabacco didn’t have a significant impact on plant growth and development. Transgenic tobacco plants with in-planta cellulose degrading enzymes showed higher biomass digestibility than wild type. Gene construction and transformation in switchgrass was much longer than expected, which delayed the research progress. Besides, in-planta engineering of lignin degrading enzyme is more challenging than cellulose degrading enzyme, in terms of expression detection. Expression of lignin degrading enzyme and cellulose degrading enzyme improved biomass yield and saccharification efficiency of switchgrass, respectively. It is promising to express both genes in switchgrass for optimized overall performance. According to the results of TEA, switchgrass biomass production cost is mainly attributed to by fertility and harvesting. Biomass production profit can increase up to 10-fold depending on biomass price. The PHA production profit is also sensitive to the biomass price. The proposed technology could potentially reduce the biomass deconstruction cost from 33% to 9% of PHA revenue, making the biomass-based PHA competitive to petroleum-based polymers even in case of relatively high biomass price of biomass. Therefore, cultivation of the genetically engineered self-deconstruction switchgrass for Polyhydroxyalkanoate (PHA) production could benefit switchgrass grower and PHA producer with attractive profits for both sectors. This new enzyme optimization approach will be beneficial for bioindustries that use energy crops as feedstocks. It will improve the economic viability of converting energy crops to renewable products that support a sustainable society and helps address the Nation’s long-term strategic needs for renewable products and reduction of reliance on fossil resources.

42 ENGINEERING↗
DOE OSTI2014

Advanced Systems for Preprocessing and Characterizing Coal-Biomass Mixtures as Next-Generation Fuels and Feedstocks

The research activities presented in this report are intended to address the most critical technical challenges pertaining to coal-biomass briquette feedstocks. Several detailed investigations were conducted using a variety of coal and biomass feedstocks on the topics of (1) coal-biomass briquette production and characterization, (2) gasification of coal-biomass mixtures and briquettes, (3) combustion of coal-biomass mixtures and briquettes, and (4) conceptual engineering design and economic feasibility of briquette production. The briquette production studies indicate that strong and durable co-firing feedstocks can be produced by co-briquetting coal and biomass resources commonly available in the United States. It is demonstrated that binderless coal-biomass briquettes produced at optimized conditions exhibit very high strength and durability, which indicates that such briquettes would remain competent in the presence of forces encountered in handling, storage and transportation. The gasification studies conducted demonstrate that coal-biomass mixtures and briquettes are exceptional gasification feedstocks, particularly with regard to the synergistic effects realized during devolatilization of the blended materials. The mixture combustion studies indicate that coal-biomass mixtures are exceptional combustion feedstocks, while the briquette combustion study indicates that the use of blended briquettes reduces NO x , CO 2 , and CO emissions, and requires the least amount of changes in the operating conditions of an existing coal-fired power plant. Similar results were obtained for the physical durability of the pilot-scale briquettes compared to the bench-scale tests. Finally, the conceptual engineering and feasibility analysis study for a commercial-scale briquetting production facility provides preliminary flowsheet and cost simulations to evaluate the various feedstocks, equipment selection and operating parameters.

01 COAL, LIGNITE, AND PEAT↗

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