Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “fossil”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 235 records · Page 13
All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

Integrated Computational Materials and Mechanical Modeling for Additive Manufacturing of Alloys with Graded Structure Used in Fossil Fuel Power Plants

Wire-arc additive manufacturing (WAAM) has demonstrated its unique capability of producing large-size alloy components with a significantly reduced fabrication time and enhanced geometry design freedom. In this project, the team has developed an ICME (Integrated Computational Materials Engineering) modeling framework, which supports the WAAM of the AUSC (Advanced Ultra-Supercritical) power plant components. The manufacturing design has been applied to Inconel 740H, steel P91, as well as the dissimilar alloy components between steel P91 and Inconel 740H. The ICME model framework is developed by considering two types of modeling. First, mechanistic modeling has been applied to control the printing quality and understand the sequence of the dissimilar printing of the wall structure. The following models have been included in the developed ICME framework: finite element thermal model, grain structure model, residual stress simulation, crystal plasticity model, CALPHAD-based precipitation kinetic model, phase stability prediction, thermal expansion predictive model, and heuristic creep model. Secondary, a physics-based machine learning model has also been developed based on the ICME model structure. The machine learning model development is based on the ICME model prediction with calibration of the experiments. In addition, the WAAM has been utilized as a high-throughput experimental tool rapidly generating a gradient of alloy composition to facilitate experimental database generation for process-structure-property relationships. Such a database directly supported the ICME-enhanced machine learning, which further assisted in intermediate composition block design between P91 and 740H. A high-throughput screening study of the oxidation resistance has been performed based on such high-throughput experimentation. Based on the computational design, several dissimilar alloy manufacturing with post-heat treatment have been performed with a comprehensive evaluation of mechanical performance, including hardness mapping, yield strength, creep resistance. In this project, the single component of P91 and 740H processed by WAAM after heat treatment designed by ICME has demonstrated higher performance in yield strength and creep resistance than the wrought materials. The P91 sample prepared by WAAM with ICME-designed heat treatment performs better than P92 in creep resistance. The designed graded alloy printing with intermediate block shows a promising performance that exceeds the traditional welding. Moreover, the current research indicates the high need for location-specific design analysis with uncertainty quantification, an important topic that deserves more dedicated research. The achievement of this project demonstrated the promising future of WAAM in structural alloy manufacturing for energy power plant development. Successful printing requires synergetic efforts made by manufacturing, mechanical, and materials sciences.

20 FOSSIL-FUELED POWER PLANTS↗
DOE OSTI2022

UK-US Collaboration on Fossil Energy R&D: Steam Side Oxidation

In recent years, interest in increasing the efficiency of power plants based on steam generation has led to the need to develop and qualify materials capable of operating at steam temperatures and pressures significantly higher than those employed in current power plants. The overall focus of this international program is on using ferritic-martensitic steels to the maximum possible temperature, before switching to austenitic steels and/or Ni-based alloys. The relatively low Cr content of these alloys raises concerns regarding their resistance to steam oxidation at these higher temperatures. Earlier work in this collaboration addressed the reliability of data from atmospheric pressure, laboratory-based steam oxidation tests. This raised issues regarding how representative the laboratory-grown oxides were compared to those formed on service-exposed material and how the tests could be made more reliable by introducing added complexity. In general laboratory-scale exposures are conducted under isothermal conditions at ambient or slightly elevated pressure, using a relatively low flow rate of steam. The coupons used in these tests are normally flat cuboids which have been ground to homogenise the surface and remove any pre-existing features. However, there is a concern that these samples and exposures are not representative of service conditions, and so it is necessary to quantify the influence of transient conditions, such as heat flux, pressure and sample geometry/surface conditions. To address such concerns a new collaborative program of work was initiated to determine the influence of these added features on oxidation kinetics and oxide scale morphology. The overall aim was to improve the understanding of alloy performance in ultrasupercritical (USC) steam conditions and qualify suitable test procedures.

20 FOSSIL-FUELED POWER PLANTS↗
DOE OSTI2023

Techno-Economic and Deployment Analysis of Fossil Fuel-Based Power Generation with Integrated Energy Storage

Most existing coal-fired power plants were designed for sustained operation at full load to maximize efficiency, reliability, and revenues. Depending on plant type and design, these plants can adjust output within a fixed range in response to plant or market conditions. The need for flexibility driven by increased penetration of variable and non-dispatchable power generation such as wind and solar is shifting traditional mission profile of thermoelectric power plants in three ways: more frequent shutdowns when market or grid conditions warrant, more aggressive load ramp rates (rate of output change), and lower minimum sustainable load, which provides a wider operating range and helps avoid costly plant shutdowns. The recent studies have shown that flexibility of a coal-fired power plant can be improved by the energy storage. The objective of this project was to analyze a set of energy storage options (technologies) and determine their impact on flexibility and economics of a representative coal-fired power plant. The effect of five Energy Storage Systems (ESSs) integrated with a coal power plant on plant flexibility and economics was investigated in this study. The results obtained in this project and presented in this report showed that ESS integrated with a thermal power plant improves plant flexibility and participation in the Energy and Ancillary Services markets and also improves plant financial performance.

20 FOSSIL-FUELED POWER PLANTS↗
DOE OSTI2022

Development of a Pipe Crawler Inspection Tool for Fossil Energy Power Plants

This document presents the final report of the research activity completed during the four years of the project and includes the major challenges and accomplishments. The report presents specific details of the engineering processes and methodologies used to develop the robotic crawler and complete the project milestones. In particular, the report includes sections that address the problem statement, background, development of crawler modules, bench scale testing, simulation development and full scale testing. The report concludes with a discussion on potential paths forward and concluding remarks.

20 FOSSIL-FUELED POWER PLANTS↗
DOE OSTI2025

Ultra-Low Disorder Graphene Quantum Dot-Based Spin Qubits for Cyber Secure Fossil Energy Infrastructure (Final Technical Report)

The overarching goal of the proposed project is to demonstrate the feasibility of creating ultralow local disorder graphene quantum dots (GQDs)-based high-speed, high-fidelity spin quantum bits (qubits) for extremely cyber-secure coal energy plants of the future. Despite their inherent benefits, the coherence times in the state-of-the-art GQD qubits are still low primarily due to the local disorder in GQD devices generated during lithographic fabrication of GQDs. Hence, the focus of this research is to prepare ultralow disorder GQDs (e.g., edge roughness ~0.5nm) and evaluate the low temperature (~mK) charge/spin transport characteristics of the engineered GQD qubit platform. To achieve minimal disorder in GQD qubits, we employ a novel approach that combines nanotomy (novel GQD fabrication technique developed by the PI) and scanning probe microscopy-atomic oxidation lithography (SPM-AOL).

20 FOSSIL-FUELED POWER PLANTS↗
NASA NTRS1992

Novel long-chain anteiso-alkanes and anteiso-alkanoic acids in Antarctic rocks colonized by living and fossil cryptoendolithic microorganisms

Saponified extracts of rock samples colonized by cryptoendolithic microbial communities from the McMurdo Dry Valleys of Southern Victoria Land, Antarctica, were separated into hydrocarbon and fatty acid fractions by silica gel column chromatography. Hydrocarbons and methyl esters of fatty acids were analyzed by capillary gas chromatography-mass spectrometry. Unusually, a suite of long-chain anteiso-alkanes (a-C20 to a-C30) and anteiso-alkanoic acids (a-C20 to a-C30) were detected in many samples, together with straight-chain, branched and/or cyclic and acyclic isoprenoid compounds. These novel compounds are probably derived from unidentified heterotrophic bacteria or symbiotic processes in a unique microbial community in the Antarctic cold desert and suggest the occurrence of a special biosynthetic pathway. Long-chain anteiso-alkanes are probably formed through microbial decarboxylation of corresponding anteiso-alkanoic acids. They may serve as new biomarkers in environmental and geochemical studies.

NASA Program Exobiology↗
DOE OSTI2021

Oxygen enrichment combustion to reduce fossil energy consumption and emissions in hot rolling steel production

The reheating furnace operation in the hot mill is natural gas- and electricity-intensive. Oxygen enrichment combustion for reheating furnaces has been proposed to curb and replace natural gas use. In this study, heat transfer in steel slabs in the combustion environment of a push-type reheating furnace was simulated using a computational fluid dynamics (CFD) model. Two oxygen enrichment methods that optimized for performance were selected— a medium oxygen enrichment (MOE) case and an oxy-fuel (OF) case. A life cycle analysis (LCA) characterized the energy and emission profiles of an integrated iron and steel manufacturing process using the two oxygen enrichment cases for the hot mill. These conditions were evaluated for energy use and carbon intensity and compared with a baseline case. Results show that with oxygen enrichment, natural gas consumption can decrease by 19.6%–26.8%, total energy consumption (natural gas and electricity) can decrease by 15.1%–20.7% in the hot mill. Emissions of greenhouse gases can decrease by 11.1%–15.2% in the two optimized cases with 14%–27% reductions in regulated criteria pollutants (nitrogen oxides, carbon monoxide, particulate matter, volatile organic compounds, black carbon, organic carbon, and volatile organic carbons). There is a tradeoff between reducing natural gas consumption and increasing electricity demand from a life cycle perspective. Although the OF case resulted in higher energy- and emissions-related benefits, the MOE case showed the more desirable heat flux uniformity, which is key to maintaining product quality. The analysis suggests that oxygen enrichment in the reheating furnace process can have a significant impact on hot mill environmental performance and become a contributing factor in transitioning to low-carbon steel manufacturing.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Cross-database comparisons on the greenhouse gas emissions, water consumption, and fossil-fuel use of plastic resin production and their post-use phase impacts

Resin production and post-use pathways have cross-database discrepancies due to different temporal/geographic representation, technologies, and assumptions. These differences can distort comparisons across alternatives and confound efforts to establish standards based on the plastics’ life-cycle impacts. Thus, this study quantifies the degree and identifies the sources of cross-database discrepancies across four LCA databases (GREET, USLCI, Ecoinvent, and GaBi) for five resin production pathways and three post-use phases. For resin production pathways, all resins showed significant cross-database discrepancy in their global warming impacts: the degree of discrepancy was significant to recommend a consistent choice of database to users any LCA comparisons across different products. For post-use phases, landfill datasets had relatively lower degree of cross-database discrepancy than incineration and mechanical recycling. Different metadata characteristics were the sources of some cross-database discrepancies while other parts could be explained by the original differences in the life-cycle inventory sourced from different producers and plants.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗