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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 1,333 records · Page 74
All sourcesNASA NTRSDOE OSTI
DOE OSTI2019

Study of Evaporation of Laser-Heated Iron–Carbon Nanoparticles Using Analysis of Thermal Radiation

Evaporation of iron nanoparticles in carbon shells under pulsed laser irradiation is analyzed. Iron–carbon nanoparticles are synthesized in a shock tube reactor with the aid of pyrolysis of the 0.25% Fe(CO){sub 5} + 0.25% C{sub 6}H{sub 6} mixture in argon. Laser radiation is used for additional heating to temperatures that exceed the evaporation threshold of the iron core of nanoparticles. Time profiles of the thermal radiation of laser-heated nanoparticles are measured. The two-color pyrometry is used to determine the evaporation temperature of nanoparticles, and the laser extinction makes it possible to monitor the loss of volume fraction of the condensed phase upon evaporation. Approximation of experimental signals of laser-heated nanoparticles using model curves is employed to determine effective enthalpy of evaporation of iron–carbon nanoparticles. It is shown that the iron core of nanoparticles is evaporated through the carbon shell and the energy spent by such a process is approximately twice greater than the evaporation enthalpy of bulk iron with free surface.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2023

Rapid screening of secondary aromatic metabolites in Populus trichocarpa leaves

Abstract Background High-throughput metabolomics analytical methodology is needed for population-scale studies of bioenergy-relevant feedstocks such as poplar ( Populus sp.). Here, the authors report the relative abundance of extractable aromatic metabolites in Populus trichocarpa leaves rapidly estimated using pyrolysis-molecular beam mass spectrometry (py-MBMS). Poplar leaves were analyzed in conjunction with and validated by GC/MS analysis of extracts to determine key spectral features used to build PLS models to predict the relative composition of extractable aromatic metabolites in whole poplar leaves. Results The Pearson correlation coefficient for the relative abundance of extractable aromatic metabolites based on ranking between GC/MS analysis and py-MBMS analysis of the Boardman leaf set was 0.86 with R 2 = 0.76 using a simplified prediction approach from select ions in MBMS spectra. Metabolites most influential to py-MBMS spectral features in the Clatskanie set included the following compounds: catechol, salicortin, salicyloyl-coumaroyl-glucoside conjugates, α-salicyloylsalicin, tremulacin, as well as other salicylates, trichocarpin, salicylic acid, and various tremuloidin conjugates. Ions in py-MBMS spectra with the highest correlation to the abundance of extractable aromatic metabolites as determined by GC/MS analysis of extracts, included m/z 68, 71, 77, 91, 94, 105, 107, 108, and 122, and were used to develop the simplified prediction approach without PLS models or a priori measurements. Conclusions The simplified py-MBMS method is capable of rapidly screening leaf tissue for relative abundance of extractable aromatic secondary metabolites to enable prioritization of samples in large populations requiring comprehensive metabolomics that will ultimately inform plant systems biology models and advance the development of optimized biomass feedstocks for renewable fuels and chemicals.

09 BIOMASS FUELS↗
DOE OSTI2018

Novel Electro-Deoxygenation Process for Bio-oil Upgrading

Biomass is a potential source of renewable fuel. Bio-oil produced by fast pyrolysis is a prospective option to replace fossil fuels for transportation. However, bio-oil needs to be upgraded to remove its high oxygen and water content, and acidity to produce useful fuels. The upgrading of bio-oil is generally accomplished by hydrodeoxygenation (HDO) using hydrogen. The instability of bio-oil poses a major challenge in transportation to central upgrading facility. An electro-deoxygenation (EDOx) process was evaluated to fully or partially deoxygenate bio-oil using solid oxide electrolysis process. This device uses an oxygen ion conducting membrane which under an applied electric potential removes oxygen in the form of an ion and transports it to the opposite side of the membrane where it is released as oxygen molecule. When water is present in the bio-oil vapor, the process generates in situ hydrogen to facilitate deoxygenation over the electrode that functions as catalyst.

09 BIOMASS FUELS↗
DOE OSTI2019

Conversion of Coal Wastes and Coal Plus Other Opportunity Fuel Mixtures, Such as Coal Plus Municipal Solids, to Produce Electricity and/or Liquid Fuels

For the foreseeable future, the Nation’s energy demand will continue to come largely from indigenous fossil energy resources and hydrocarbon fuels. Specifically waste coal plus other opportunity fuels need to be utilized as a feedstock to eliminate a waste stream and optimized to maximize energy yield and cleanly minimize pollutant emissions. Modular equipment is needed for installation in coal preparation locations, military installations, and research park facilities. Thermal decomposition of coal, biomass, and mixed solid waste (MSW) have been shown to reduce a waste stream while providing liquid and gaseous fuel products with low pollutant emissions. However, thermal decomposition processes have several challenges associated with preprocessing biomass and MSW, feeding and conveying material into the reactor, and post processing of syngas to remove undesirable products while upgrading to increase yield of high value products. Increasing total energy output from power plants by utilizing biomass and mixed wastes ultimately lowers energy costs, harmful environmental impacts of emissions, and has significant impacts on the energy security and sustainability of the U.S. economy. Entrained flow gasifiers (EFGs) produce very little CH4 and a wide range of H2/CO ratios (0.5–2.0) but are limited in their ability to effectively feed large biomass or MSW particles into the reactor. A solution to the feeding problems is to use pyrolysis torrefaction (PT) for conversion of waste materials to create a feedstock similar to coal and capable of grinding down and mixing with the coal feed. Mainstream experimentally explored reaction pathways for the conversion of coal waste plus municipal solids (CWPMS) and demonstrated a bench-scale reactor used for torrefaction of the municipal solid waste (MSW) to create a coal-like feed for blending with the coal waste. The material was processed in a pilot-scale EFG to determine product yield and emissions with CWPMS fuels, as well as the ash content and slagging properties of these feedstocks. The PT-EFG system was experimentally validated, where emissions and yield data were used to develop a high-fidelity process model and economic analysis. The following was accomplished in the Phase I: Determined optimal torrefaction process conditions for MSW and biomass through TGA; maximized heating value of fuel while maximizing final mass of torrefied product Demonstrated torrefaction of MSW and biomass feedstocks at 334°C, pulverized to uniform 74 µm particle size, and processed into coal-like feedstocks Demonstrated 8 lb/h pilot-scale EFG using MSW and biomass blends with waste coal; demonstrated 100% biomass in EFG Determined major effects of MSW torrefaction and co-gasifying high-ash coal waste-MSW blends have on pilot-scale EFG Demonstrated blending low-ash, low-sulfur torrefied biomass with high-ash waste bituminous and anthracite refuse coals generates a higher quality syngas compared to syngas from high-ash waste coals Demonstrated a high carbon conversion (> 99.5%) and syngas with 29.47% H2 content, and 0% CH4 content; greater water–gas shift occurs in EFG than predicted by equilibrium ASPEN Plus model Blended lower-ash, high-alkali biomass MSW to lower slag viscosities of the high-ash coal refuse sufficiently for better slag flow compared to feeding the high-ash coal Used low-sulfur biomass to greatly reduce the EFG syngas H2S concentrations and produce non-leachable slag and quench water with very little organic and trace metal contamination Developed a process model and TEA showing the modular PT EFG is cost competitive to existing power plants with the advantage of using low- or negative-value feedstocks such as waste coal stockpiles and non-landfilled MSW; providing a large incentive to implement an economical PT-EFG process

30 DIRECT ENERGY CONVERSION↗
DOE OSTI2020

Building Blocks from Biocrude: High-Value Methoxyphenols (Final Scientific/Technical Report)

Integrating biofuels production with bioproducts presents an opportunity to explore options for recovering high-value chemicals as additional revenue-generating products from biofuel conversion pathways. Thus, the overall objective of this project was to develop a comprehensive separation strategy to economically recover valuable methoxyphenols (MPs) consisting of guaiacol, 4-methylguaiacol, 4-ethylguaiacol, 4-propylguaiacol, eugenol, and isoeugenol from biocrude as building blocks to demonstrate that bioproducts could enable cost-effective production of biofuels via integrated catalytic pyrolysis and hydroprocessing. The upgradability of the remaining biocrude fraction to biofuel after separation of the products was evaluated by hydrotreating. Finally, techno-economic analysis (TEA) was performed to examine the economic potential of recovering select MPs from biocrude in parallel with biofuels production.

09 BIOMASS FUELS↗
DOE OSTI2021

Rapid Construction of Validated Chemistry Models for Advanced Biofuels (Co-Optima Final Report)

Computer methods were developed and demonstrated that make it possible to predict the combustion and pyrolysis chemistry of proposed biofuels, even before the biofuels are ever manufactured or experimentally tested. The methods are based on first-principles calculations of reaction rates and equilibria. A large number of complicated calculations are required, so we developed a computer workflow that automates many of the steps. With the chemical structure of the biofuel and the system conditions (temperature, pressure, compositions, etc.) as the input, the computer methods can construct a detailed kinetic model with refined parameters without intense human intervention. The automation of model construction makes it practical for a single engineer to make the predictions in a reasonable time period. The accuracy of the computer predictions was tested by measuring the time-profiles of various reaction intermediates (carbon monoxide, carbon dioxide, water, formaldehyde, methane, and ethylene) formed as the biofuels pyrolyze or ignite using sophisticated laser shock tube methods. Several biofuels, including methyl propyl ether, cyclopentanone, butyl acetate isomers, etc., were carefully studied to demonstrate the validity of the proposed computational and experimental methodology. This research project opens up the possibility for assessing some proposed biofuels on the computer without expensive experimental campaigns. The new computer methods are open source and well-documented, allowing a knowledgeable modeler to easily access the developed methods and implement them in their work routine. Moreover, they are also convenient and powerful, promising for developing the fuel chemistry models needed for use in engine simulators, facilitating co-optimization of new engine designs with new fuels.

09 BIOMASS FUELS↗
DOE OSTI2023

Comparative Techno-Economic Analysis of Available Feedstocks for High-Temperature Conversion: Whole Tree Thinnings and Mature Pine Residues

The TEA and LCA impacts of utilizing low-cost feedstocks in a high-temperature conversion process are of great interest. Here, we investigate the conversion cost impacts of two underutilized feedstocks from the commercial pine industry; 13-year-old whole trees, representing trees removed for the purpose of pre-commercial thinning, and 23-year-old pine residues, representing a waste stream produced from the deconstruction of mature trees for other purposes. Experimental fast pyrolysis data for each feedstock was used in tandem with results from supply and preprocessing analyses in order to evaluate the field-to-fuel economics. A low difference in MFSP was found between the conversion costs for the two feedstocks, with residues demonstrating a net benefit of $0.27/GGE compared to the whole tree thinnings, driven primarily by feedstock supply costs. This suggests that both whole tree thinnings and pine residues may be viable feedstock options for CFP conversion. Life cycle inventories were also generated for each case, enabling a field-to-fuel quantification of the cost and carbon cycle associated with each feedstock.

09 BIOMASS FUELS↗
DOE OSTI2022

Decontamination of Mixed Paper and Plastic Municipal Solid Waste Increases Low and High Temperature Conversion Yields

With the implementation of China’s Green Fence Policy and the following National Sword Policy, there is a need to divert previously accepted waste materials away from the landfill. Mixed plastic and paper wastes that are too contaminated to be economically recycled can be used for conversion into fuels and products. The effect of common contaminants present in waste streams must be determined to make municipal solid waste (MSW) a viable alternative to agricultural feedstocks for conversion. In this study, MSW was sourced from a dual stream materials recovery facility (MRF) in Emmet County, Michigan and characterized via mass balance. The most common contaminants in mixed paper and plastic were quantified and targeted for decontamination when mixed paper was explored for low temperature conversion pathways and plastics for high temperature conversion pathways. Ink, stickies, and plastic contamination were sorted out of the mixed paper stream and did not have an impact on sugar yields during enzymatic hydrolysis (EH). Although no improvement in yield was found, it was noted that copy paper within the mixed paper stream had an elevated pH and higher concentration of fermentation inhibitors, suggesting that intrinsic properties of some paper types may not be ideal for EH and fermentation conversion. Dilute alkaline pretreatment and mechanical refining of mixed paper increased the EH yield of mixed paper, suggesting this previously established process could be used as a decontamination method. “Dirt” and particulates were washed from mixed plastic using either an aqueous detergent or a non-aqueous chemical washing method. Liquid oil yields were increased during microwave assisted fast pyrolysis. All decontamination techniques met the cost target of less than $30/dry ton with plastic decontamination ranging from $18.16 to $24.81/dry ton. Because dilute alkaline pre-treatment and mechanical refining is considered part of the conversion process, the decontamination cost during feedstock preprocessing was considered $0/dry ton.

09 BIOMASS FUELS↗
DOE OSTI2018

Flame-Sprayed Pure and Ce-Doped TiO 2 Photocatalysts

Pure and Ce-doped TiO 2 nanoparticles were successfully synthesized in one step by means of the scalable flame spray pyrolysis (FSP) process. Complete structural and chemical characterization of these materials revealed that the majority of the nanoparticles are crystalline and spherical, ranging from 5 to 45 nm in diameter. Furthermore, the band gap of TiO 2 was reduced by doping with Ce from 2.43 to 3.06 eV and the Ce–TiO 2 nanoparticles exhibit a strong photoelectrical response to visible light illumination. Ce–TiO 2 nanoparticles obtained with this scalable method are trivially scalable to industrial level manufacturing, granting and enabling additional approaches for the actual application of ceramic oxide nanomaterials to combat challenges such as environmental cleanup and energy production from the visible part of solar inputs.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2017

Impact of Thermal Pretreatment Temperatures on Woody Biomass Chemical Composition, Physical Properties and Microstructure

Thermal pretreatment of biomass by torrefaction and low temperature pyrolysis has the potential for generating high quality and more suitable fuels. To utilize a model to describe the complex and dynamic changes taking place during these two treatments for process design, optimization and scale-up, detailed data is needed on the property evolution during treatment of well-defined individual biomass particles. The objectives of this study are to investigate the influence of thermal pretreatment temperatures on wood biomass biochemical compositions, physical properties and microstructure. Wild cherry wood was selected as a model biomass and prepared for this study. The well-defined wood particle samples were consecutively heated at 220, 260, 300, 350, 450 and 550 °C for 0.5 h under nitrogen. Untreated and treated samples were characterized for biochemical composition changes (cellulose, hemicellulose, and lignin) by thermogravimetric analyzer (TGA), physical properties (color, dimensions, weight, density and grindablity), chemical property (proximate analysis and heating value) and microstructural changes by scanning electron microscopy (SEM). Hemicellulose was mostly decomposed in the samples treated at 260 and 300 °C and resulted in the cell walls weakening resulting in improved grindability. The dimensions of the wood were reduced in all directions and shrinkage increased with increased treatment temperature and weight loss. With increased treatment temperature, losses of weight and volume increased and bulk density decreased. The low temperature pyrolyzed wood samples improved solid fuel property with high fuel ratio, which are close to lignite/bituminous coal. Morphology of the wood remained intact through the treatment range but the cell walls were thinner. Lastly, these results will improve the understanding of the property changes of the biomass during pretreatment and will help to develop models for process simulation and potential application of the treated biomass.

09 BIOMASS FUELS↗
NASA NTRS2024

Residual Thrust in a Solid Rocket Motor: A Model Applied to the Mars Ascent Vehicle

A model for solid rocket motor residual thrust is built from the concept that hot nozzle phenolic or carbon materials provide a radiating source of heat flux to the insulation, leading to continued off-gassing by pyrolysis. This model is 1. Fitted to flight datasets and scaled to the Mars Ascent Vehicle second stage motor (MAV SRM2), and 2. Derived with MAV SRM2 design and material estimates. The two methods show a potential range of modeling uncertainty for use by mission analysts. Further loss methods that could reduce the maximum residual impulse are identified but left to further work to evaluate.

Solid rocket motors↗
NASA NTRSDate not supplied

Residual Thrust in a Solid Rocket Motor: A Model Applied to the Mars Ascent Vehicle

A model for solid rocket motor residual thrust is built from the concept that hot nozzle phenolic or carbon materials provide a radiating source of heat flux to the insulation, leading to continued off-gassing by pyrolysis. This model is 1. Fitted to flight datasets and scaled to the Mars Ascent Vehicle second stage motor (MAV SRM2), and 2. Derived with MAV SRM2 design and material estimates. The two methods show a potential range of modeling uncertainty for use by mission analysts. Further loss methods that could reduce the maximum residual impulse are identified but left to further work to evaluate.

Solid rocket motors↗
NASA NTRSDate not supplied

In Situ Synchrotron Micro-CT of Microballoon-Filled RTV Silicone During Thermal Decomposition

This work investigates the thermal decomposition of microballoon-filled room-temperature-vulcanizing (RTV) silicone using time-resolved synchrotron micro-CT at the Advanced Light Source. In situ imaging of constrained and unconstrained samples captures the evolution of the internal microstructure during heating, including material expansion, microballoon and void growth, tearing, pyrolysis, shrinkage, and increasing porosity. The measurements provide new insight into the mechanisms governing RTV degradation and generate three-dimensional data for future quantitative analysis and material-response model development.

TPS↗
DOE OSTI2019

Low-Cost Production of Versatile Bio-Oil

Fact sheet describing the advantages, value propositions, and differentiators of the catalytic fast pyrolysis technology to produce low-cost, versatile bio-oil.

09 BIOMASS FUELS↗