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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 1,621 records · Page 90
All sourcesNASA NTRSDOE OSTI
DOE OSTI2012

Conversion of residual organics in corn stover-derived biorefinery stream to bioenergy via microbial fuel cell

A biorefinery process typically uses about 4-10 times as much water as the amount of biofuel generated. The wastewater produced in a biorefinery process contains residual sugars, 5-furfural, phenolics, and other pretreatment and fermentation byproducts. Treatment of the wastewater can reduce the need for fresh water and potentially add to the environmental benefits of the process. Use of microbial fuel cells (MFCs) for conversion of the various organics present in a post-fermentation biorefinery stream is reported here. The organic loading was varied over a wide range to assess removal efficiency, coulombic efficiency and power production. A coulombic efficiency of 40% was observed for a low loading of 1% (0.66 g/L) and decreased to 1.8% for the undiluted process stream (66.4 g/L organic loading). A maximum power density of 1180 mW/m2 was observed at a loading of 8%. Excessive loading was found to result in poor electrogenic performance. The results indicate that operation of an MFC at an intermediate loading using dilution and recirculation of the process stream can enable effective treatment with bioenergy recovery.

Borole, Abhijeet P↗
DOE OSTI2014

Computation Of The Residual Radionuclide Activity Within Three Natural Waterways At The Savannah River Site

In 2010 a Composite Analysis (CA) of the U.S. Department of Energy’s (DOE’s) Savannah River Site (SRS) was completed. This investigation evaluated the dose impact of the anticipated SRS End State residual sources of radionuclides to offsite members of the public. Doses were assessed at the locations where SRS site streams discharge into the Savannah River at the perimeter of the SRS. Although the model developed to perform this computation indicated that the dose constraint of 0.3 mSv/yr (30 mrem/yr), associated with CA, was not approached at the Points of Assessment (POAs), a significant contribution to the total computed dose was derived from the radionuclides (primarily Cs-137) bound-up in the soil and sediment of the drainage corridors of several SRS streams. DOE’s Low Level Waste Federal Review Group (LFRG) reviewed the 2010 CA and identified several items to be addressed in the SRS Maintenance Program. One of the items recognized Cs-137 in the Lower Three Runs (LTR) Integrator Operable Unit (IOU), as a significant CA dose driver. The item made the recommendation that SRS update the estimated radionuclide inventory, including Cs-137, in the LTR IOU. That initial work has been completed and its radionuclide inventory refined. There are five additional streams at SRS and the next phase of the response to the LFRG concern was to obtain a more accurate inventory and distribution of radionuclides in three of those streams, Fourmile Branch (FMB), Pen Branch (PB) and Steel Creek (SC). Each of these streams is designated as an IOU, which are defined for the purpose of this investigation as the surface water bodies and associated wetlands, including the channel sediment, floodplain sed/soil, and related biota. If present, radionuclides associated with IOUs are adsorbed to the streambed sediment and soils of the shallow floodplains that lie immediately adjacent to stream channels. The scope of this effort included the evaluation of any previous sampling and analysis data that had been collected for various SRS investigations, as well as the additional streambed and floodplain sampling and analysis data acquired more recently as part of the ongoing SRS IOU program, and associated specifically with the FMB, PB, and SC IOUs. Samples have been acquired along the waterways, within the stream channels themselves and in the adjacent floodplain zones. While Cs-137 is the most significant and abundant radionuclide associated with the SRS waterways, it is not the only radionuclide, hence work was conducted to evaluate all radionuclides present.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2014

Removal of residual particulate matter from filter media

A method for removing residual filter cakes that remain adhered to a filter after typical particulate removal methodologies have been employed, such as pulse-jet filter element cleaning, for all cleanable filters used for air pollution control, dust control, or powder control.

42 ENGINEERING↗
DOE OSTI2015

Design of a diagnostic residual gas analyzer for the ITER divertor

One of the ITER diagnostics having reached an advanced design stage is a diagnostic RGA for the divertor, i.e. residual gas analysis system for the ITER divertor, which is intended to sample the divertor pumping duct region during the plasma pulse and to have a response time compatible with plasma particle and impurity lifetimes in the divertor region. Main emphasis is placed on helium (He) concentration in the ducts, as well as the relative concentration between the hydrogen isotopes (H2, D2, T2). Measurement of the concentration of radiative gases, such as neon (Ne) and nitrogen (N2), is also intended. Numerical modeling of the gas flow from the sampled region to the cluster of analysis sensors, through a long (~8m long, ~110mm diameter) sampling pipe terminating in a pressure reducing orifice, confirm that the desired response time (~1s for He or D2) is achieved with the present design.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2018

Removal of residual particulate matter from filter media

A method for removing residual filter cakes that remain adhered to a filter after typical particulate removal methodologies have been employed, such as pulse-jet filter element cleaning, for all cleanable filters used for air pollution control, dust control, or powder control.

42 ENGINEERING↗
DOE OSTI2017

Laboratory-based validation of the baseline sensors of the ITER diagnostic residual gas analyzer

The divertor-specific ITER Diagnostic Residual Gas Analyzer (DRGA) will provide essential information relating to DT fusion plasma performance. This includes pulse-resolving measurements of the fuel isotopic mix reaching the pumping ducts, as well as the concentration of the helium generated as the ash of the fusion reaction. In the present baseline design, the cluster of sensors attached to this diagnostic's differentially pumped analysis chamber assembly includes a radiation compatible version of a commercial quadrupole mass spectrometer, as well as an optical gas analyzer using a plasma-based light excitation source. This paper reports on a laboratory study intended to validate the performance of this sensor cluster, with emphasis on the detection limit of the isotopic measurement. This validation study was carried out in a laboratory set-up that closely prototyped the analysis chamber assembly configuration of the baseline design. This includes an ITER-specific placement of the optical gas measurement downstream from the first turbine of the chamber's turbo-molecular pump to provide sufficient light emission while preserving the gas dynamics conditions that allow for \textasciitilde 1 s response time from the sensor cluster [1].

Biewer, Theodore↗
DOE OSTI2018

Flow Behavior of Particulate Pine Forest Residues and Corn Stover: A Comparison of Experiments and Simulations

Feeding and handling problems have been recognized as a major contributor to low production of renewable cellulosic ethanol in the US, which achieved only 7% of nameplate capacity in 2016. In this work we compare the flow behavior of pine forest residues and corn stover at various particle sizes and moisture contents in instrumented pilot-scale hopper tests and instrumented shear testers to continuum finite element method (FEM) and discrete element method (DEM) models. The shear testers include a Schulze ring shear tester, a custom large Peschl-style tester, and a modified Johanson direct shear tester. In addition to measurements of normal force and torque, the shear testers are also instrumented with arrays of pressure transducers. Modeling approaches include a Drucker-Prager model, a micropolar hypoelasticity model, and DEM simulations employing non-spherical, deformable particles. Results from physical experiments indicate that continuum elastoplastic models, such as Drucker-Prager models, do not account for the full complexity of biomass flow, and that more advanced rheological models are better able to predict nuances of the flow behavior, especially the compressive stress field.

09 BIOMASS FUELS↗
DOE OSTI2020

Pilot Plant Reliability Metrics for Grinding and Fast Pyrolysis of Woody Residues

The reliability of biomass size reduction, feeding, and conversion processes remains a critical technical hurdle and important cost driver for biomass conversion systems. While Biorefinery projects have typically focused on scaling up conversion technologies that maximize yield of desired products, e.g. fuels and chemicals, solids handling and reactor feeding systems are often considered secondarily. These are frequently scaled down or adapted from other industries, without a full appreciation of how biomass heterogeneity and variability impact process reliability. Here we present the effects of feedstock variability on relative throughput, mass loss, plant uptime, operator intervention, product yield, and product quality for grinding and fast pyrolysis operations at the pilot scale. Loblolly pine residues were sourced and collected using commercial harvesting techniques. Grinding and pyrolysis experiments were performed at INL's Biomass Feedstock National User Facility and NREL's Thermal and Catalytic Process Development Unit, respectively. Preprocessing throughput using a hammer mill varied between 31-48% of nameplate capacity (5 tons/hr), and fast pyrolysis throughput varied between 57-72% of nameplate capacity (20 kg/hr) for an overall system throughput of 18-35% of nameplate capacity across biomass preprocessing and conversion to pyrolysis oil. Pyrolysis oil yields varied between 46-53% (feedstock carbon to oil, dry basis). Grinder overloads in the size reduction step were more prevalent for lower ash and higher moisture materials. During fast pyrolysis operations, downtime was caused by bridging in the feed and char removal systems and plugging in the condensation system, and significant variation in the type and frequency of operator intervention was observed between feedstocks. Cohesion of solids (feedstock and char) leading to system plugging appeared less problematic for higher ash feedstocks, and differences in condenser plugging behavior between high and low ash feedstocks indicates the composition and physical nature of the deposited material is important for process reliability and is feedstock dependent.

09 BIOMASS FUELS↗
DOE OSTI2015

A Multi-Sample Residual Resistivity Ratio System for High Quality Superconductor Measurements

For developing accelerator cavity materials, superconducting transition temperature (TC), transition width (ΔTC), and residual resistivity ratio (RRR), are useful parameters to correlate with SRF performance and fabrication processes of bulk, thin film, and novel materials. The RRR gauges the purity and structure of the superconductor based on the temperature dependence of electron scattering in the normal conducting state. Combining a four point probe delta pulse setup with a switch allows multiplexing of the electrical measurements to 32 samples per cooldown cycle. The samples are measured inside of an isothermal setup in a liquid helium (LHe) dewar. The isothermal setup is required for a quasistatic warmup of the samples through TC. This contribution details the current setup for collecting RRR and TC data, the current standard of throughput, measurement quality of the setup, and the improvements underway to increase the system’s resolution and ease of use.

Spradlin, J. K.↗
DOE OSTI2020

Heat treatment to anneal residual stresses during additive manufacturing

An additive manufacturing system having a heat source for melting powder particles in a desired shape and pattern to produce a product. A secondary heat source is used for heat treating the product to achieve heat treatment. The secondary heat source is used to peen or anneal residual stresses caused by the additive manufacturing process.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Process Control Plan to Monitor Acceptable Levels of Flux and other residues

IPC J-STD –001G, Amendment 1 requires that the assembler have a sampling plan to assure that the process remains in control once qualified and validated. It is well documented that electrochemical failures occur at component sites where flux residues are not fully activated. It is also well known that specific components have a higher risk of electrochemical failure. Selecting a control plan that monitors the process and its performance on challenging components provides assurance that the process maintains control once established during process qualification. The test board used to qualify the process establishes an upper and lower spec limit for each of the component types on the test board. Surface Insulation Resistance upper and lower control limits, using challenging components that are representative of production hardware, represent a golden process condition. The golden image is a measure of process deviations that represents the performance of a resistance curve within a specific period. The objective is to judge whether the process in or out of control.

42 ENGINEERING↗
DOE OSTI2012

Sulfur residues in niobium electropolishing

Electropolishing (EP) in sulfuric/hydrofluoric acid mixtures affords significantly greater surface smoothness than the incumbent buffered chemical polishing (BCP), making it attractive as the future baseline technology for SRF cavity manufacture. However, reported observations of particulate sulfur residues raise concern. One hypothesis is sulfate reduction to elemental sulfur at the cathode, where the measured potential drop is thermodynamically sufficient. Alternatively, the low effectiveness of the cathode?s aluminum oxide surface as a hydrogen recombination catalyst could lead to accumulation of atomic hydrogen, a powerful reductant. We explored these possibilities under standard EP conditions in a small three-electrode laboratory cell. We varied aluminum cathode area to obtain different current densities (and thus overpotentials) at constant cell current. We substituted platinum, an excellent hydrogen recombination catalyst, for aluminum in some experiments. Surface of cathodes were examined with Scanning Electron Microscope (SEM). Surface composition was analyzed by Energy Dispersive X-Ray Spectroscopy (EDS) and X-Ray Photoelectron Spectroscopy (XPS).

Reece, Charles↗
DOE OSTI2023

Life-Cycle Greenhouse Gas Emission Impacts of Forest Residue Pre-processing with Wet Milling

The goal of this analysis was to evaluate the environmental impact of a Case Study that uses wet milling to preprocess logging residues before feeding to a catalytic fast pyrolysis conversion step. The results of the Case Study were compared to those of the status quo Base Case system where dry milling is used. The results reveal that wet milling achieved 65% lower GHG emissions per dry ton of conversion-ready feedstock than the conventional dry milling technology. This is mainly because wet milling greatly reduced the energy consumption for drying. In addition, wet milling also generates fewer fines, thus improving the throughput of conversion-ready feedstock

biomass preprocessing↗
DOE OSTI2023

Particle Scale Impacts on Deconstruction Energy of Pine Residues

The goal of this Case Study was to quantify the impacts of variable moisture and ash on hammer mill throughput and energy consumption and on generation of fines that are not able to be fed to conversion, as compared to a status quo Base Case system. Also considered was convertible carbon content (minimum carbon specification) and maximum ash content and the delivered feedstock cost impacts of not being able to feed residue not meeting both specifications to the conversion reactor. Laboratory data on the impacts of input particle size and moisture content on the exit particle size were received from FCIC Subtask 5.2: Preprocessing, High Temperature Conversion Preprocessing from their single particle impact population balance modeling study (Tiasha Bhattacharjee, INL). Additional throughput and energy consumption data were obtained from FCIC Subtask 5.2 (Jordan Klinger, INL) for the same grinder with a 6 mm screen in place. These data were utilized to develop the necessary response surface equations to perform throughput analysis using discrete event simulation. Because the ash contents in the separated fines had not been analyzed in the laboratory at the time of the model runs, we chose to assume that the ash distributed proportionally with total mass into the overs and unders in the disk screen following grinding.

energy consumption↗