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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.

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At least 1,243 records · Page 69
All sourcesNASA NTRSDOE OSTI
DOE OSTI2019

Technology Advancements in Hydroprocessing of Bio-oils

This manuscript describes the research and development undertaken at Pacific Northwest National Laboratory subsequent to an earlier bio-oil hydrotreating historical development review in 2007. It also includes the implications for future development needs related to hydroprocessing of biomass fast pyrolysis bio-oil for liquid hydrocarbon fuels production. The results of the research, the use of the results to develop models for technical and economic analyses of the state of the technology, the needs and implications for additional research and development, as well as the future potential for technology transfer to industrial application are included.

Fast Pyrolysis, Hydrotreating↗
DOE OSTI2025

Process design and techno-economic analysis for bio-based graphite and liquid hydrocarbons production from lignocellulosic biomass

The worldwide demand for graphite, as the main anode material for Li-ion batteries, is expected to double by 2028 since it supports the use of electricity, including transient renewable sources, for energy storage, sustainable mobility, and automation. However, the dependence on non-renewable and external resources jeopardizes the world supply chain. This study explores the technical and economic performance of transforming lignocellulosic biomass into biographite and fuel-grade hydrocarbons through pyrolysis bio-oil upgrading. According to simulation results, the total power demand for the biorefinery reached 10,784 kWh per tonne of biographite, of which 36 % can be supplied by the heat integration network and power plant. Sensitivity and risk analyses were conducted to evaluate the economics, with process yields identified as the most relevant indicators to the minimum selling price (MSP). The analysis revealed a promising cost-competitive range for biographite MSP against fossil-based graphite (medium quality synthetic graphite Chinese market price ~$\$$4.2/kg). Case D, which includes biofuels as a byproduct, presents the best metrics, reaching a MSP of $\$$3.3/kg of anode-grade biographite with a profit margin of 27 %. While including biofuels in the product slate provides the best economic performance, the uncertainty associated with the big capital investment makes its risk 13 % higher to attain an IRR >20 % than the case in which biographite is produced as a standalone product. Overall, this study demonstrates that integrated biorefineries can produce a cost-competitive bio-based anode material for Li-ion batteries.

09 BIOMASS FUELS↗
DOE OSTI2024

Biocompatible organosolv fractionation via a novel alkaline lignin-first strategy towards lignocellulose valorization

Simultaneous valorization of both carbohydrate and lignin fractions in lignocellulose remains a great challenge. Herein, a novel lignin-first strategy using triethylene glycol (TEG) under alkaline conditions for effective biomass fractionation producing highly digestible carbohydrates and reactive lignin was developed. Delignification was over 80% and fermentable sugar yields were close to 90% after pretreatment at 90°C. The biocompatibility of TEG allowed direct enzymatic hydrolysis of the solid residue without washing, thus minimizing wastewater generation. Furthermore, the obtained lignin (TEGL) had an uncondensed structure with well-preserved β-O-4 linkage, leading to near-equal aromatic monomer yields compared to cellulolytic enzyme lignin after catalytic-free pyrolysis, demonstrating high valorization potential. Finally, the proposed TEG solvent system is promising for a green and sustainable biorefinery process to achieve the complete utilization of lignocellulose.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2024

Reduced-order condensed-phase kinetic models for polyethylene, polypropylene and polystyrene thermochemical recycling

Thermochemical recycling of plastic waste (PW) into chemicals and energy vectors requires coupling particle and reactor-scale simulations to accurate condensed phase pyrolysis mechanisms for each constituent. This work proposes a methodology to derive reduced-order condensed-phase kinetic models from validated semi-detailed kinetic mechanisms. Two types of kinetic models are obtained for polyethylene (PE), polypropylene (PP) and polystyrene (PS): reduced semi-detailed models and multi-step fully lumped ones. These families offer different compromises between accuracy and computational cost. The former employ 50–100 gas + liquid species and describe both the radical degradation and the detailed carbon distribution of the products. Conversely, the latter involves 5–10 species per polymer tracking only the main petroleum cuts. The kinetic mechanisms are complemented by the definition of thermochemical properties of gas, liquid, and solid-phase species, accounting for phase-transitions through pseudo-chemical reactions. Model validations are performed by comparison with experimental data and the original semi-detailed mechanisms in terms of mass loss, heat fluxes and product distribution profiles. The resulting CHEMKIN-like condensed-phase models are attached as Supplementary Material and as a GitHub repository. Extending the proposed approach to other polymers and coupling it with existing subsets in the CRECK kinetic framework (e.g., biomass, PVC, PET) offers a powerful tool to model thermochemical recycling of PW and biomass/PW mixtures.

kinetics↗
DOE OSTI2026

Theoretical and kinetic modeling study of hydrazine oxidation

The present work constitutes the first theoretical and kinetic modeling study of hydrazine oxidation, which may be important for burnout in ammonia-fueled combustion. The kinetics of the oxidation of N 2 H 4 , N 2 H 3 and tHNNH by molecular oxygen were investigated via a quantum chemistry/canonical transition state theory approach. Geometries and anharmonic frequencies were obtained with density functional theory, and energies from coupled cluster calculations (CCSD(T)) extrapolated to the infinite basis set limit, with corrections for core-valence electron correlation, scalar relativistic effects, and higher level correlation up to lambda coupled cluster, CCSDT(Q) Λ . The key reactions occurred on the N 2 H 4 O 2 potential energy surface, where the results indicated a fast reaction of N 2 H 3 with HO 2 via singlet adducts to yield tHNNH + H 2 O 2 and HNN(H)O + H 2 O, while reaction on the triplet surface proceeds via a bound complex followed by a tight, submerged barrier to yield N 2 H 4 + O 2 . The results were incorporated in a detailed reaction mechanism, which was used to interpret the shock tube results from Michel and Wagner (1965) on the effect of O 2 on hydrazine conversion at 1100–1400 K. The kinetic model captured qualitatively the observed behavior, but underestimated the reaction rate under oxidizing conditions. The hydrazine pyrolysis chemistry dominated conversion at reducing conditions and/or high temperature. At oxidizing conditions and intermediate temperatures (≲ 1400 K), reactions of N 2 -amines with HO 2 and O 2 were important for the oxidation rate.

Ab initio calculations↗
DOE OSTI2020

Reactions of Propyl Radicals: A Shock Tube - VUV Photoionization Mass Spectrometry Study

The pyrolytic reactions of n-propyl and i-propyl radicals and their precursors have been investigated at elevated temperatures and pressures (600 – 900 K and 5 – 8 bar). The studies were performed in a miniature high repetition rate shock tube with synchrotron vacuum ultraviolet photoionization mass spectrometry yielding comprehensive datasets of temporal and photoionization energy dependencies of reagents and products. The propyl radicals were generated by pyrolysis of alkyl nitrites. In addition to the main decomposition path, NO elimination, the mass spectra allowed an alternative minor path via HNO elimination to be identified and quantified. For the n-propyl precursor the HNO elimination route accounted for 9% of the alkyl nitrite while for the i-propyl precursor it was 2.5%. These values are in good agreement with a recent study on i-butyl radicals in the same apparatus at similar conditions. The ratio of disproportionation/recombination was obtained for n- propyl from the relative concentrations of n-hexane and propene and for i-propyl from 2,3-dimethyl butane and propene. For n-propyl the ratio is 0.3 and 1.2 for i-propyl, both are independent of temperature and pressure over the experimental range. The disproportionation/recombination ratios are about a factor of 2 higher than prior evaluations that are based mainly on room temperature data. The experimental results are some of the first from the apparatus used and comments are made about the technique, challenges encountered, and suggestions for future developments.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2022

Molecular weight growth by the phenyl + cyclopentadienyl reaction: Well-skipping, ring-opening, and dissociation

Radical-radical reactions contribute to molecular weight growth of polycyclic aromatic hydrocarbons (PAHs), but their role is not well understood. The phenyl (Ph, C 6 H 5 ) + cyclopentadienyl (C 5 H 5 ) reaction has not been studied but can serve as a surrogate reaction for many reactions of larger aryl-σ radicals with resonance-stabilized π-radicals. The adducts of these reactions easily lose an H atom to produce a new π-radical. Here, through a combination of dilute flash pyrolysis experiments, theory, and simulation, we find that for the title reaction, substantial Ph—C 5 H 4 + H is formed, dominantly by a well-skipping pathway, at conditions around 30 Torr and 1400 K. This radical is thermally stable at moderate temperatures but decomposes at higher temperatures following ring opening of the 5-member ring. Products corresponding to the loss of H, C 2 H 2 , and C 3 H 3 are observed experimentally. Calculation of the C 11 H 9 potential energy surface affirms that these are expected decomposition products and reveals multiple possible pathways.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2022

A comprehensive experimental and kinetic modeling study of di-isobutylene isomers: Part 2

A wide variety of high temperature experimental data obtained in this study complement the data on the oxidation of the two di-isobutylene isomers presented in Part I and offers a basis for an extensive validation of the kinetic model developed in this study. Due to the increasing importance of unimolecular decomposition reactions in high-temperature combustion, we have investigated the di-isobutylene isomers in high dilution utilizing a pyrolysis microflow reactor and detected radical intermediates and stable products using vacuum ultraviolet (VUV) synchrotron radiation and photoelectron photoion coincidence (PEPICO) spectroscopy. Additional speciation data at oxidative conditions were also recorded utilizing a plug flow reactor at atmospheric pressure in the temperature range 725-1150 K at equivalence ratios of 1.0 and 3.0 and at residence times of 0.35 s and 0.22 s, respectively. Combustion products were analyzed using gas chromatography (GC) and mass spectrometry (MS). Ignition delay time measurements for di-isobutylene were performed at pressures of 15 and 30 bar at equivalence ratios of 0.5, 1.0, and 2.0 diluted in 'air' in the temperature range 900-1400 K using a high-pressure shock-tube facility. New measurements of the laminar burning velocities of di-isobutylene/air flames are also presented. The experiments were performed using the heat flux method at atmospheric pressure and initial temperatures of 298-358 K. Moreover, data consistency was assessed with the help of analysis of the temperature and pressure dependencies of laminar burning velocity measurements, which was interpreted using an empirical power-law expression. Electronic structure calculations were performed to compute the energy barriers to the formation of many of the product species formed. The predictions of the present mechanism were found to be in adequate agreement with the wide variety of experimental measurements performed.

09 BIOMASS FUELS↗
DOE OSTI2024

Characterization of coal extracts and their performances as binder for new carbon-based structural units

Coal production and usage have been declining in the past decade due to the transition to renewable energies, environmental regulations to reduce environmental pollution due to direct coal combustion from coal-fired power stations, and administrative policies. This downturn has created tremendous challenges for the coal industry, and many states rely on revenue from coal mining. Developing new valorization routes with high coal demand is essential and using coal-derived materials to make engineered products does offer an eco-friendly, attractive, and value-added use. This paper presents a brief introduction to the extraction process to derive coal deposits, extracts, and residuals (CDERs) and a comprehensive characterization analysis to determine the suitability of CDERs as binders to produce an innovative construction material named the carbon-based structural unit (CSU). CDERs are used to prepare the CSU with or without using mesophase pitch (MP) as binders and selected CDERs are heat-treated and pressure-heat-treated to improve their binding capabilities. The performances of the CSU specimens are evaluated based on compressive strength, density, and thermal conductivity. The CSU specimens mixed with distilled residue (DR) to pyrolysis char (PC) ratio of 1:2 achieve a compressive strength of 54.85 MPa, which is higher than the compressive strength of 30 MPa of normal concrete. The CSU specimens with deposit (De) and tetralin insoluble (TI) require the addition of MP to obtain compressive strengths greater than 30 MPa. Furthermore, these CSU specimens possess a relatively low density of about 1 g/cm 3 and low thermal conductivity of less than 0.25 W/m.K.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Efficient kinetic thermal inverse modeling for organic material decomposition

The prevalent use of organic materials in manufacturing is a fire safety concern, and motivates the need for predictive thermal decomposition models. A critical component of predictive modeling is numerical inference of kinetic parameters from bench scale data. Currently, an active area of computational pyrolysis research focuses on identifying efficient, robust methods for optimization. This paper demonstrates that kinetic parameter calibration problems can successfully be solved using classical gradient-based optimization. We explore calibration examples that exhibit characteristics of concern: high nonlinearity, high dimensionality, complicated schemes, overlapping reactions, noisy data, and poor initial guesses. The examples demonstrate that a simple, non-invasive change to the problem formulation can simultaneously avoid local minima, avoid computation of derivative matrices, achieve a computational efficiency speedup of 10x, and make optimization robust to perturbations of parameter components. Techniques from the mathematical optimization and inverse problem communities are employed. By re-examining gradient-based algorithms, we highlight opportunities to develop kinetic parameter calibration methods that should outperform current methods.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2025

The composition of gases from a diffusion flame above longleaf pine needle fuel beds

The gas and tar composition of a diffusion flame from longleaf pine needles is currently poorly understood and more data are needed to fill in the gap between pyrolysis data and smoke plume data, thus improving physical and chemical modeling of wildland smoke formation. A pilot experiment to measure light gas and tar composition of such a flame is described for three flame regions: persistent flame (flame base), intermittent flame, and smoke plume. Flame gases from 24 experimental fires were collected in canisters and analyzed using EPA method TO-14A for CO 2 , CO, H 2 , CH 4 , and C 2 to C 7 hydrocarbon gases. Condensed gas (tar) samples were collected and analyzed using GC/MS. Other light gases were measured using FTIR spectroscopy. Results from compositional data analysis suggest significant differences in (relative) concentration of compounds detected in the three regions of the flame. Statistical tests for differences in flame zones were performed using the canister data: Concentration of hydrocarbons relative to CO and CO 2 decreased from the persistent flame zone above the pyrolyzing needles through the intermittent flame region into the flame-free plume. This was likely due to both chemical reactions (oxidation) occurring in the flame as well as the introduction of air into the flame/plume by entrainment.

Biomass↗
DOE OSTI2020

A scalable approach of using biomass derived glycerol to synthesize cathode materials for lithium-ion batteries

Glycerol, a main byproduct of biodiesel, was used as the fuel agent in a scalable flame-assisted spray pyrolysis approach to synthesize micron-size cathode materials. Single droplet combustion, particle morphology, and electrochemical performance were examined considering the effects of salt concentration, water addition, and post-annealing time on synthesizing Li(Ni 1/3 Co 1/3 Mn 1/3 )O 2 (NCM111) cathode materials. Single droplet tests showed that a sufficient amount of water in the glycerol-based precursor could delay droplet inflation and ignition. Moreover, using a two-fluid atomization nozzle, spray tests demonstrated that adding water would result in less wrinkled and more uniform particles. Nevertheless, increasing water proportion in the precursor could reduce the reaction heat, resulting in that samples prepared with water addition needed longer post-annealing time to improve their electrochemical performance. Using the precursor without water, the best performed NCM111 cathode material was synthesized with only 2 h of post-annealing. It has a discharge capacity of 163.3 mAh/g at 0.1C and 85.5% capacity retention at 1C after 100 cycles. Furthermore, the current work confirmed the capability of using glycerol as a sustainable fuel agent to synthesize NCM111 cathode materials, and also provided basic conditions for the development of large-scale production in the future.

25 ENERGY STORAGE↗
DOE OSTI2018

Characteristics of Co3O4 and cobalt nanostructured microspheres: Morphology, structure, reduction process, and magnetic properties

Highlights: • The metal cobalt samples consist in both α-Co with a hexagonal close-packed lattice and β-Co face-centered cubic crystal at reduction temperatures 220, 240, 300 and 350 °C. • Co{sub 3}O{sub 4} reduction proceeded in successive stages: water removal, residual salt removal, Co{sub 3}O{sub 4} → CoO and CoO → Co transitions. • Inheritance of morphology may have droplet–Co{sub 3}O{sub 4}–Co association. - Abstract: Nanostructured magnetic cobalt microspheres were synthesized using a two-stage method. First, nanostructured cobalt oxide Co{sub 3}O{sub 4} microspheres were produced by ultrasonic spray pyrolysis at different temperatures from 800 to 1100C. Second, the nanostructured powders obtained were reduced to metal cobalt in an hydrogen atmosphere at different temperatures from 220 to 350C. In this study the evolution of the morphology from Co{sub 3}O{sub 4} nanostructured microspheres to nanostructured Co, resulting from the Co{sub 3}O{sub 4} reduction process, and the structure of metal cobalt, were investigated. It was found that the metal cobalt agglomerates have the same shape and mean diameter (∼ 1,5 μm) as those of the cobalt oxide, Co{sub 3}O{sub 4}. The amount of Co microspheres with smaller diameters decreased with increasing reduction temperature. Also, the β-Co content increased with increasing reduction temperature.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2018

Catalytic activities of two different morphological nano-MnO2 on the thermal decomposition of ammonium perchlorate

Highlights: • Nano-MnO{sub 2} was produced easily. • Nano-MnO{sub 2} can promote the decomposition of AP. • Sea-urchin nano-MnO{sub 2} is a superior catalyst. - Abstract: In order to investigate the catalytic activity of nano-MnO{sub 2} on the thermal decomposition of ammonium perchlorate, two different shapes of nano-MnO{sub 2} (sea-urchin and linear) were prepared by the hydrothermal method with MnSO{sub 4}·H{sub 2}O and Na{sub 2}S{sub 2}O{sub 8}, MnSO{sub 4}·H{sub 2}O and (NH{sub 4}){sub 2}S{sub 2}O{sub 8}, respectively. X-ray diffraction, scanning electron microscopy and the nitrogen adsorption/desorption analysis were used to characterize the structure of the nanocomposites. The sea-urchin nano-MnO{sub 2} possesses a greater specific surface area than the linear nano-MnO{sub 2}. The catalytic properties of nano-MnO{sub 2} on the thermal decomposition of ammonium perchlorate (AP) were demonstrated by differential scanning calorimeter (DSC). As show in the DSC carves, the addition of the sea-urchin nano-MnO{sub 2} got the thermal decomposition peak temperature of AP reduced much more than the addition of the linear nano-MnO{sub 2}, the low-temperature decomposition process even disappeared, and the high-temperature pyrolysis peak temperature decreased by 94.6 °C. All evidences indicated that the sea-urchin nano-MnO{sub 2} is a better catalytic than the linear one.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2018

Cost-effective fabrication of (g-C3N4 + Mo) added photostable ZnO thin films for enhanced visible light responsive photocatalytic dye degradation

Highlights: • First report on ZnO:Mo/GCN films prepared by simple cost-effective jet nebulizer spray method for dye degradation. • A remarkable enhancement in the photocatalytic dye degradation efficiency is achieved for ZnO. • The mechanism for the enhanced degradation is explained on the basis of the obtained point of zero charge values. • Optical, PL, SEM and XPS studies support the discussion on the photocatalytic property of ZnO:Mo/GCN. - Abstract: The photocatalytic activity of ZnO:Mo/GCN (ZnO:Molybdenum/g-C{sub 3}N{sub 4}) thin films deposited using a simple cost-effective jet nebulizer spray pyrolysis technique with different Mo doping concentrations (1,2 and 3 at.%) was studied. The photocatalytic degradation test was carried out against Methylene blue (MB) and Rhodamine B (RhB) dyes under visible light. It is found that thin film of ZnO:Mo/GCN with 1 at.% of Mo exhibits superior photocatalytic efficiency compared with the other samples. The degradation rate constant of this sample is 0.0727 and 0.0268 min{sup −1} for the tested MB and RhB dyes, respectively which are nearly two times and four times greater than the respective rate constant values of pristine ZnO. The mechanism involved in the enhanced photocatalytic activity is addressed with the help of obtained results. The properties of the deposited samples are correlated appropriately with the photocatalytic efficiency of the samples. The photostability of the prepared catalysts is tested experimentally.

36 MATERIALS SCIENCE↗
DOE OSTI2018

A facile and low-cost synthesis of MnOx/Mn2NNC nanohybrid as an advanced oxygen reduction electrocatalyst

Highlights: • We demonstrate a facile route to fabricate a novel MnO{sub x}/Mn{sub 2}NNC hybrid. • MnO{sub x}/Mn{sub 2}NNC displays an excellent ORR activity. • MnO{sub x}/Mn{sub 2}NNC affords overwhelmingly better durability than 20 wt% Pt/C. - Abstract: We demonstrate a one-step, low-cost and easily scalable pyrolysis route to fabricate a novel MnO{sub x}/Mn{sub 2}NNC nanohybrid with MnO{sub x}/Mn{sub 2}N nanoparticles (20–30 nm) anchored on the wrinkled N-doped carbon nanosheets (denoted as NC). MnO{sub x}/Mn{sub 2}NNC displays a remarkably higher ORR activity than that of NC, suggesting that the MnO{sub x}/Mn{sub 2}N nanoparticles play an important role in enhancing the ORR activity. Furthermore, MnO{sub x}/Mn{sub 2}NNC exhibits overwhelmingly better durability than commercial 20 wt% Pt/C, to be specific, 93.7% current retention after continuous operation for 24,000 s, while 59.7% for 20 wt% Pt/C.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2018

Nitrogen-doped hollow carbon nanospheres for highly sensitive electrochemical sensing of nitrobenzene

Highlights: • NHCPs were prepared using MSM as a template and PDA as carbon and nitrogen precursor. • NHCPs-750 with high content of pyrindinic N showed good electrocatalytic performance. • A sensitive electrochemical sensor for NB was developed based on the NHCPs-750–GCE. - Abstract: Following hard template method, nitrogen–doped hollow carbon nanospheres (NHCPs) were successfully prepared by using monodisperse silica microspheres as a template and dopamine as carbon and nitrogen precursor. A series of NHCPs-x samples with different pyrolysis temperatures were reported. The composite material formation was characterized by detailed methods (e.g., X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, scanning electron microscopy and transmission electron microscopy). Results indicated that NHCPs treated at 750 °C with highest amounts of pyrindinic N showed improved electro-catalytic activity for nitrobenzene (NB) in neutral solution. NHCPs-750 can be developed as an effective sensing platform for the detection of NB, which showed high activity and superior analytical performance, such as a wide linear range of 5–2610 μM, a high sensitivity of 436 μAmM{sup −1}, and a low limit of detection of 2.29 μM.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2018

Enhanced rate performance of Li3V2(PO4)3/C cathode by an improved rheological phase assisted microwave method

Highlights: • Rheological phase assisted microwave can utilize both advantages of two methods. • Polyethylene glycol was used as both rheological medium and carbon precursor. • 101.8 mA h g{sup −1} of specific capacity was obtained at 50 C rates. - Abstract: In this study, high-rate Li{sub 3}V{sub 2}(PO{sub 4}){sub 3}/C composite is successfully synthesized via an improved rheological phase assisted microwave method using polyethylene glycol as both rheological medium and carbon precursor. The relatively uniform Li{sub 3}V{sub 2}(PO{sub 4}){sub 3} particles are encapsulated in amorphous carbon architecture to form core-shell structure, providing effective electron and ion transport. When used as a cathode material in lithium ion battery, the Li{sub 3}V{sub 2}(PO{sub 4}){sub 3}/C composite displays a maximum discharge capacity of 101.8 mA h g{sup −1} at 50 C charge/discharge rate and still possesses 98.3% of capacity retention after 100 cycles, demonstrating superior rate capability and excellent cycling stability when compared with bare Li{sub 3}V{sub 2}(PO{sub 4}){sub 3}. The observed electrochemical performance could be attributed to uniform coated-carbon pyrolysis from polyethylene glycol rheological phase precursor and small Li{sub 3}V{sub 2}(PO{sub 4}){sub 3} pristine particles synthesized by the fast microwave heating route.

36 MATERIALS SCIENCE↗