Search NASA⌕ Search

Engineering topics

Cvetic, Patricia

Publications and source records attributed to Cvetic, Patricia.

17 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Functionalization of nitrogen vacancy-containing nanodiamonds with a metal-organic framework for quantum sensing applications

Nitrogen vacancy (NV)-containing nanodiamonds (NDs) are an important material in applications such as biological imaging, catalysis, and, in particular, quantum sensing. Careful manipulation of the surface coating on NV NDs is essential for both enhancing quantum sensor performance and for tuning selectivity towards specific sensing targets. Here, we demonstrate a simple synthetic approach for functionalizing NV NDs with the zeolitic imidazole framework-8 (ZIF-8) metal–organic framework (MOF), providing a well-ordered, porous scaffold for immobilizing target analytes near the NV ND surface. The composites were structurally characterized by x-ray diffraction, electron microscopy, and X-ray photoelectron spectroscopy, and these results were all consistent with NV NDs fully encapsulated by ZIF-8. Critically, the luminescent properties of the NV NDs, which are vital for quantum sensing experiments such as optically detected magnetic resonance (ODMR), are unchanged by the MOF coating. Moreover, spin relaxometry experiments indicate that the ZIF-8 coating significantly enhances the NV ND spin longitudinal relaxation time T1, a critical quantum parameter for sensing applications. Given the tremendous structural diversity of MOFs, the NV ND@MOF composites are an exciting material class with exciting implications for the development of high-performance quantum sensors.

Crawford, Scott↗
DOE OSTI2024

Natural Gas Combined Cycle Power Plants with Carbon Capture and Exhaust Gas Recycle

This is a presentation given at the 3rd International Conference on Energy and Environment. The presentation highlights analysis work conducted by NETL to assess the cost and performance for natural gas combined cycle (NGCC) power plants that incorporate solvent-based post combustion carbon dioxide (CO2) capture and exhaust gas recycle (EGR). Increasing the inlet CO2 concentration by EGR is expected to improve the efficiency of the capture system and reduce its cost, however the analysis results show that the cost improvement is minimal as is the cost of capture reduction.

Hackett, Gregory↗
DOE OSTI2023

Natural Gas Combined Cycle (NGCC) Power Plants with Carbon Capture and Exhaust Gas Recycle (EGR)

The purpose of this study is to determine the cost and performance of natural gas combined cycle (NGCC) power plants using state-of-the-art gas turbines with post combustion carbon capture and recycle streams designed to increase the CO 2 concentration in the inlet to the capture system. Increasing the inlet CO 2 concentration by exhaust gas recycle (EGR) is expected to improve the efficiency of the capture system and reduce its costs. Primary results indicate that adding EGR to NGCC plants with CO 2 capture results in minimal improvement to the cost of electricity. The addition of 50 percent EGR in NGCC plants with CO 2 capture reduces the LCOE by 2 percent over the LCOE of the same design without EGR as reference. Including the EGR ductwork and cooler in a greenfield plant design could still be prudent since there is some cost advantage to EGR and it would allow more flexibility for taking advantage of future improvements in the technology.

20 FOSSIL-FUELED POWER PLANTS↗
DOE OSTI2023

Analysis of Carbon Capture Retrofits for Cement Plants

The objective of this study is to provide an estimate of the cost to capture CO 2 in retrofit applications at cement plants. The cement plant configurations considered in this study include natural gas and solid fuel (coal and coke) cases, and both wet- and dry kiln-fed plant designs, however the base cement plants in this study were not evaluated other than characterization of their kiln off-gas stream and high-level quantification of heat integration potential at the existing plant. In each case, the base cement plant produces 1.5 M tonnes per year of finished cement, assuming 91.4 percent clinker content. This analysis includes a 10 percent retrofit cost increase for process integration and low grade heat recovery, when compared to the analogous non-heat integration case. Heat integration is considered as a potential offset to capture system heating demands (i.e., as a percentage reduction). Recovery and reuse of excess heat from the base cement plant can provide economic benefits—primarily by reducing the need to purchase supplemental natural gas for CO 2 solvent regeneration—but any process improvement must be great enough to overcome the cost increases (i.e., capital and O&M) necessary to realize those benefits. With heat integration potential of 10 percent and 30 percent, that benefit wasn’t significant enough to offset the increase in capital and operating costs, and a cost of capture increase was observed based on the assumptions in this report. Benefits of heat integration potential may be realized when natural gas prices are higher, as demonstrated in the sensitivity to natural gas price where crossover points exist between heat integration cases and their respective non-heat integration cases. Four of the base cases were further evaluated to explore the cost implications of deeper levels of gas pre-treatment to remove oxides of nitrogen (NOx) and oxides of sulfur (SOx) from the kiln off-gas stream prior to CO 2 capture, purification, and compression. The results of these additional case analyses showed a 7.4–18.8 percent increase in cost of capture over the respective base case (i.e., analogous cases without SOx/NOx removal).

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2023

Cost of Capturing CO 2 from Industrial Sources

The objective of this study is to provide an estimate of the cost to capture carbon dioxide (CO 2 ) from select industrial processes (ammonia, ethylene oxide, ethanol, natural gas processing, coal-to-liquids, gas-to-liquids, refinery hydrogen, cement, iron/steel, and pulp/paper). Each of the ten processes were chosen for analysis due to either the high purity of the CO 2 emission source (99–100 mole percent CO 2 ) or the large quantity of CO 2 potentially available. For each industrial process considered, available plant information, such as existing average plant size, projected new development plant size, or existing plant operations data was used to develop a reference plant for this study.

20 FOSSIL-FUELED POWER PLANTS↗
DOE OSTI2022

Additional Analysis of Carbon Capture at Industrial Facilities

This poster provides summary cost details for a technoeconomic analysis of CO2 capture from flue gas generated by cement plants, conducted by U.S. Department of Energy National Energy Technology Laboratory and presented at the 2022 Carbon Management Project Review Meeting held in Pittsburgh, PA (August 15-19, 2022). A range of modern cement plant configurations was considered, along with different fuel types (coal, coke, and natural gas) and two levels of CO2 capture (95% and 99%). The sensitivity of capture cost to a range of modeling assumptions (such as fuel price, financing assumptions, utilization rate, and plant size) was also conducted, to show possible cost ranges that could be expected for decarbonization of typical cement plants in the U.S.

Hughes, Sydney↗
DOE OSTI2021

Reactivity of CO 2 with Utica, Marcellus, Barnett, and Eagle Ford Shales and Impact on Permeability

We report that in order to reduce greenhouse gas emissions while recovering hydrocarbons from unconventional shale formations, processes that make use of carbon dioxide to enhance oil recovery while storing carbon dioxide (CO 2 ) should be considered. Here, we examine samples from three shale basins across the United States (Utica and Marcellus Shales in the Appalachian Basin, Barnett Shale in the Bend Arch-Ft. Worth Basin, and Eagle Ford in the Western Gulf Basin) to address the following questions: (1) do changes from reaction with CO 2 and fluids at the micrometer and nanometer scale alter flow pathways and, in turn, impact hydrocarbon production, CO 2 storage, and seal integrity and (2) can CO 2 or fluid reactivity be predicted based on physical or chemical properties of shale formations? Experiments were conducted at 40 °C and 10.3 MPa to characterize the interaction between CO 2 and shale using X-ray diffraction (XRD), carbon and sulfur analysis, in situ Fourier transform infrared spectroscopy (FT-IR), feature relocation scanning electron microscopy coupled with energy-dispersive spectroscopy (SEM-EDS), mercury (Hg) intrusion porosimetry, and Brunauer-Emmett-Teller (BET) surface area and pore size analysis coupled with density functional theory (DFT) methods. Changes in mechanical, physical, and flow properties of shale cores due to CO 2 exposure were addressed using a New England Research Autolab 1500 and Xenon X-ray computed tomography (CT) scanning. Results showed that CO 2 did not promote significant reactivity with the shale if water was not present; only shales with swelling clays or residual interstitial pore water reacted with dry CO 2 to promote reactivity in shale. When water was added as a reactant, CO 2 formed carbonic acid and reacted with the shale to dissolve carbonate pockets, etched and pitted the shale matrix surfaces, and increased the microporosity and decreased nanoporosity. Porosity and permeability increased appreciably in core shale samples after exposure to CO 2 saturated fluid due to dissolution of carbonate. Shale mechanical properties were not altered. Trends were not observed that could tie CO 2 or fluid reactivity to physical or chemical properties of the shale formations at the basin scale from the samples we examined. However, if the shale contained significant amounts of carbonate and water was available to react with the CO 2 , pore sizes were altered in the matrix and permeability and porosity increased.

04 OIL SHALES AND TAR SANDS↗
DOE OSTI2021

Universal Approach to Rapid Amplified Plasmonic Sensing Using Helix Defect Phase Transition Polymers

Abstract Permittivity sensing is a critically important analytical tool for bioscience, environmental, and industrial applications. The response time for commonly used plasmonic permittivity sensors is fundamentally set by the reaction kinetics of chemically adsorbed analytes. In this work, the proposal is to overcome this limit by combining plasmonic sensors with phase transition materials possessing a rapid amplified electrostatic response such as quadrupole moment induced molecular helix reversal. As a proof‐of‐concept, rapid sensing of CO 2 on a phase transition polytetrafluoroethylene substrate and amplification of permittivity response in plasmonic Fabry–Perot sensor is shown. The demonstrated universal approach holds promise for a wide range of applications in fast, real time sensing and monitoring of biological and environmental processes.

Shugayev, Roman↗
DOE OSTI2020

Characterizing Pore-Scale Geochemical Alterations in Eagle Ford and Barnett Shale from Exposure to Hydraulic Fracturing Fluid and CO 2 /H 2 O

As demand increases for an affordable energy source that is tied to an environmental obligation to reduce greenhouse gas emissions and water usage, there is a growing consideration in shale production utilizing processes such as 1) enhancing hydrocarbon recovery via carbon dioxide (CO 2 ) flooding, 2) using CO 2 as a fracturing agent to minimize water use, and 3) storing CO 2 in depleted shale formations to mitigate emissions to the atmosphere. Understanding the geochemical reactions and alterations that occur as shale is exposed to fluids and CO 2 is necessary to develop and optimize each of these processes for field applications. While the majority of shale formations are stimulated using traditional fracturing fluid, some may be fractured using CO 2 or other non-traditional means. We examine the effect fracturing fluid has on shale and how it behaves with secondary exposure to dry CO 2 or CO 2 -saturated water using in situ Fourier Transform infrared spectroscopy (FTIR), feature relocation scanning electron microscopy (SEM), and surface area and pore size analysis using volumetric gas sorption. These techniques were performed on Eagle Ford and Barnett shale samples that were exposed to fracturing fluid and unexposed (as received). Shales that have been exposed to traditional fracturing fluid experienced two reaction fronts. The first reaction front was formed during exposure to the fracturing fluid (pH of ~1.4). A secondary reaction front was formed as a result of CO 2 -saturated fluid exposure in the form of carbonic acid (pH ~5.6). These two different reaction mechanisms drove multiple dissolution and precipitation cycles which altered petrophysical properties of the shale and could lead to a significant impact on flow pathways. FTIR showed that equilibration of carbonate dissolution and precipitation cycles could take as long as 35 days. Samples exposed to fracturing fluid showed significantly less carbonate reactivity compared to those exposed to water. Pore size analysis results indicate exposure to fracturing fluid blocked small nanopores (10-15 nm) reducing BET surface area and total pore volume. SEM results show barite precipitated heavily during exposure to fracturing fluid. It appeared that carbonic acid was able to extract sulfur from organic matter to form gypsum evaporites. The mineralogical (barite precipitation and calcite dissolution/precipitation) and pore-scale alterations observed in these samples may lead to enhancement of flow pathways for injected CO 2 or produced hydrocarbons.

04 OIL SHALES AND TAR SANDS↗