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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 829 records · Page 46
All sourcesNASA NTRSDOE OSTI
DOE OSTI2017

An environmentally friendly ball milling process for recovery of valuable metals from e-waste scraps

Highlights: • A new ball milling process was successfully developed for recovery of metals from e-waste. • The process produce soluble metallic compound with dry ball milling and benefits the leaching process. • Precious metals were successfully separated from base metals during the process. • Mechanism of the mechanochemical reactions was proposed. - Abstract: The present study reports a mechanochemical (MC) process for effective recovery of copper (Cu) and precious metals (i.e. Pd and Ag) from e-waste scraps. Results indicated that the mixture of K{sub 2}S{sub 2}O{sub 8} and NaCl (abbreviated as K{sub 2}S{sub 2}O{sub 8}/NaCl hereafter) was the most effective co-milling reagents in terms of high recovery rate. After co-milling with K{sub 2}S{sub 2}O{sub 8}/NaCl, soluble metallic compounds were produced and consequently benefit the subsequent leaching process. 99.9% of Cu and 95.5% of Pd in the e-waste particles could be recovered in 0.5 mol/L diluted HCl in 15 min. Ag was concentrated in the leaching residue as AgCl and then recovered in 1 mol/L NH{sub 3} solution. XRD and XPS analysis indicated that elemental metals in the raw materials were transformed into their corresponding oxidation state during ball milling process at low temperature, implying that solid–solid phase reactions is the reaction mechanism. Based on the results and thermodynamic parameters of the probable reactions, possible reaction pathways during ball milling were proposed. Suggestion on category of e-waste for ball milling process was put forward according to the experiment results. The designed metal recovery process of this study has the advantages of highly recovery rate and quick leaching speed. Thus, this study offers a promising and environmentally friendly method for recovering valuable metals from e-waste.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2023

Formation of Zeolites Responsible for Waste Glass Rate Acceleration: An Experimental and Computational Study for Understanding Thermodynamic and Kinetic Processes

Before nuclear waste glasses can be disposed at geological disposal facilities, a performance assessment (PA) must be conducted to provide confidence to the regulators and public that the release rates of radioisotopes and hazardous materials into the environment are below the regulatory limits. Because the release rate of radionuclides is directly related to the dissolution rate of the radionuclide-containing glass, the corrosion behavior of the glass must be well understood for the disposal site lifetime. For simplicity, glass dissolution in static conditions has been categorized into three different stages, referred to as initial rate (Stage I), residual rate (Stage II) and, depending upon the secondary phases formed, a possible delayed resumption in the alteration rate (Stage III). The last of these stages is the least understood and has the possibility to drive radionuclide release rates above regulatory thresholds.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2016

New Catalyst Reduces Wasted Carbon in Biofuel Process, Lowers Cost

Researchers at NREL recently developed a catalyst formulation that incorporates more hydrogen into the DME-to-high-octane gasoline process, resulting in a higher yield to gasoline-range products. Further, the researchers developed a secondary process that efficiently couples a portion of the gasoline-range product to yield jet/diesel fuels. The modified catalyst doubles the conversion rate of DME, which can be produced from biomass, to the high-octane gasoline product and significantly decreases the formation of wasted byproducts. For the distillate-range product, 80% of the mixture is in line with ASTM standards for use as a jet fuel blendstock. The increased productivity of high-octane gasoline and the development of a value-added distillate blendstock process further improve the economic viability toward commercially implementing this renewable fuels process.

09 BIOMASS FUELS↗
DOE OSTI2015

Current status of solid waste management in small island developing states: A review

Highlights: • Waste management is a matter of great concern for small island developing states. • On average, waste generation rate in these islands amounts to 1.29 kg/capita/day. • Illegal dumping and landfilling prevail in most small island developing states. • Sustainable waste management practices, previously absent, are now emerging. • However, many challenges still hinder the implementation of these practices. - Abstract: This article reviews the current status of waste management in Small Island Developing States (SIDS) and the challenges that are faced in solid waste management. The waste generation rates of SIDS were compared within the three geographic regions namely Caribbean SIDS, Pacific SIDS and Atlantic, Indian Ocean, Mediterranean and South China (AIMS) SIDS and with countries of the Organisation for Economic Co-Operation and Development (OECD). Only Pacific SIDS had a waste generation rate less than 1 kg/capita/day. The waste generation rates for the three SIDS regions averaged 1.29 kg/capita/day while that for OECD countries was at a mean value of 1.35 kg/capita/day. The waste compositions in the different SIDS regions were almost similar owing to comparable consumption patterns while these differed to a large extent with wastes generated in OECD countries. In SIDS, the major fraction of MSW comprised of organics (44%) followed by recyclables namely paper, plastics, glass and metals (total: 43%). In contrast, MSW in OECD countries consisted mainly of recyclables (43%) followed by organics (37%). This article also reviewed the other functional elements of the waste management systems in SIDS. Several shortcomings were noted in the process of waste collection, transfer and transport namely the fact of having outdated collection vehicles and narrow roads which are inaccessible. Among the waste management practices in SIDS, waste disposal via landfilling, illegal dumping and backyard burning were favoured most of the time at the expense of sustainable waste treatment technologies such as composting, anaerobic digestion and recycling.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2015

Waste minimization efforts at the H-Canyon nuclear materials processing facility located at the Savannah River Site - 15535

During the last decade, the H-Canyon at the Savannah River Site (SRS) has employed various means to minimize liquid waste generation and/or to segregate liquid waste that favors generation of low level vs high level wastes. The primary drivers were cost reduction and support of SRS liquid waste tank farm feed to the SRS's Defense Waste Processing Facility. Recent High Level Waste (HLW) volume restrictions (transfers of liquid waste from the H-Canyon to the SRS's Liquid Waste System) imposed on H-Canyon have renewed waste minimization efforts. For the next several years, H-Canyon is faced with a HLW transfer reduction of approximately 65% (reduced from approximately 300,000 gallons to 100,000 gallons). This comes at a time when H-Canyon (and a companion facility named HB-Line) are about to begin executing two high profile missions. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2023

MHTLS Cross-flow Heat Exchanger Temperature Performance Data

The presentation and supporting information provide data on the performance of an engineering-scale cross-flow heat exchanger used in hydrothermal liquefaction (HTL). Temperature profiles are provide for the process of waste water treatment sludges and a food waste. The data can be used to model larger-scale heat exchangers used in HTL.

Bioenergy Technologies Tags Heat Exchanger HTL MHT↗
DOE OSTI2019

Gas Generation Testing of Crystalline Silicotitanate Ion Exchange Media

The Direct Feed Low-Activity Waste (DFLAW) process has been proposed to support early production of immobilized low-activity waste (LAW) at the Hanford site. As planned, Hanford tank waste would be sent to the Tank Side Cesium Removal (TSCR) system for solids removal (by filtration) and cesium removal (by ion exchange) during the initial phase of the DFLAW process. The resultant treated waste would be delivered to the LAW Vitrification Facility at the Hanford Tank Waste Treatment and Immobilization Plant (WTP) for immobilization. The ongoing technology maturation of TSCR system components is being conducted by Washington River Protection Solutions, LLC (WRPS). The ion exchange process in the TSCR system will use columns of crystalline silicotitanate (CST) to remove cesium from the LAW. This report describes gas generation testing of the crystalline silicotitanate ion exchange media that was conducted to strengthen the technical basis of the media for use in the TSCR system. Specifically, the described study will inform the safety basis of both the operation of the TSCR system and the interim storage condition of the TSCR ion exchange columns after loading. Previous data on gas generation of CST are limited to a handful of studies using CST or similar media under unrepresentative conditions and durations. The safety basis underlying operation and storage of the CST columns needs to consider the rate and extent of radiolytic flammable gas generation. No existing studies provide a comprehensive set of gas generation data for column operating and storage conditions representative of those expected for TSCR. To address the data gap, this study was conducted under the following conditions (each in duplicate): (1) CST in water at 25°C tested to 300 Mrad total dose, (2) wet CST (soaked in water, then free-drained) at 25°C tested to both 300 Mrad and 900 Mrad total dose, (3) dry CST (air-dried, free-flowing material equilibrated to laboratory conditions) at 25°C tested to both 300 Mrad and 900 Mrad total dose, (4) CST in 5.6M Na simulant at 25°C tested to 300 Mrad total dose, and (5) CST in 5.6M Na simulant with 1%(w/w) total organic carbon as Na3-HEDTA at 25°C and 70°C tested to 300 Mrad total dose. For each of the listed conditions, the generation of the following gas species was measured: hydrogen, oxygen, nitrous oxide, and methane. The test data was used to determine the amount of gas generated (total and on a per component basis), gas generation rates normalized to the CST bed volume tested, and G-values for each gas species. The reported results illustrate that the CST in water condition bounds the gas generation rate (at 25°C) of all other conditions, but there is some variability in the hydrogen G-value, depending on the lot of CST tested and the amount of residual moisture present at the start of the test.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2019

Gas Generation Testing of Crystalline Silicotitanate Ion Exchange Media

The Direct Feed Low-Activity Waste (DFLAW) process has been proposed to support early production of immobilized low-activity waste (LAW) at the Hanford site. As planned, Hanford tank waste would be sent to the Tank Side Cesium Removal (TSCR) system for solids removal (by filtration) and cesium removal (by ion exchange) during the initial phase of the DFLAW process. The resultant treated waste would be delivered to the LAW Vitrification Facility at the Hanford Tank Waste Treatment and Immobilization Plant (WTP) for immobilization. The ongoing technology maturation of TSCR system components is being conducted by Washington River Protection Solutions, LLC (WRPS). The ion exchange process in the TSCR system will use columns of crystalline silicotitanate (CST) to remove cesium from the LAW. This report describes gas generation testing of the crystalline silicotitanate ion exchange media that was conducted to strengthen the technical basis of the media for use in the TSCR system. Specifically, the described study will inform the safety basis of both the operation of the TSCR system and the interim storage condition of the TSCR ion exchange columns after loading. Previous data on gas generation of CST are limited to a handful of studies using CST or similar media under unrepresentative conditions and durations. The safety basis underlying operation and storage of the CST columns needs to consider the rate and extent of radiolytic flammable gas generation. No existing studies provide a comprehensive set of gas generation data for column operating and storage conditions representative of those expected for TSCR. To address the data gap, this study was conducted under the following conditions (each in duplicate): (1) CST in water at 25°C tested to 300 Mrad total dose, (2) wet CST (soaked in water, then free-drained) at 25°C tested to both 300 Mrad and 900 Mrad total dose, (3) dry CST (air-dried, free-flowing material equilibrated to laboratory conditions) at 25°C tested to both 300 Mrad and 900 Mrad total dose, (4) CST in 5.6M Na simulant at 25°C tested to 300 Mrad total dose, and (5) CST in 5.6M Na simulant with 1% (w/w) total organic carbon as Na 3 -HEDTA at 25°C and 70°C tested to 300 Mrad total dose. For each of the listed conditions, the generation of the following gas species was measured: hydrogen, oxygen, nitrous oxide, and methane. The test data was used to determine the amount of gas generated (total and on a per-component basis), gas generation rates normalized to the CST bed volume tested, and G-values for each gas species. The reported results illustrate that the CST-in-water condition bounds the gas generation rate (at 25°C) of all other conditions, but there is some variability in the hydrogen G-value, depending on the lot of CST tested and the amount of residual moisture present at the start of the test.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2017

Use of Uncertainty in Modeling DFLAW Treatment at Hanford - 17115

Average or mean is understood by most; standard deviation (SD) is understood by few. Certainty is easy to model; uncertainty is not. The flowsheet simulation, described in this paper, placed uncertainties in the G2 model of the Hanford Tank Waste Treatment and Immobilization Plant's (WTP) Direct Feed Low-Activity Waste (DFLAW) process for performance and sensitivity evaluations. G2 is a dynamic material balance model that starts and proceeds with operating logic until all the feed is processed. Dynamic material balance is achieved by tracking the flows, storage, and change of all materials within the plant as time increments. Processing equipment and limitations of the flowsheet are modeled (e.g., equipment types, piping, volumes, flowrates, efficiencies, and physical and chemical environments that impact separations, phase equilibriums, and chemical reactions). Operating logic represents the rules and strategies of a running plant. The G2 model simulated both certainty and uncertainty scenarios for comparison purposes. For the uncertainty scenarios, process decisions were made using presumed values to simulate various operational measurement errors and process variabilities. Presumed means that the known G2 values are adjusted to replicate measurement errors and variabilities. These include: 1) volume measurement, 2) sample analysis, 3) melter decontamination factor (DF), 4) glass former weighing, and 5) glass former composition variations. The errors were randomly generated in accordance with SD values of measurement devices, laboratory methods, and glass former composition ranges. The G2 model runs give insight on the DFLAW process' controllability and the expected range of glass properties. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
NASA NTRS1995

A new process and equipment for waste minimization: Conversion of NO(x) scrubber liquor to fertilizer

A new emissions control system for the oxidizer scrubbers that eliminates the current oxidizer liquor waste and lowers the NO(x) emissions is described. Since fueling and deservicing spacecraft constitute the primary operations in which environmental emissions occur, this will eliminate the second largest waste stream at KSC. This effort is in accord with Executive Order No. 12856 (Federal Compliance with Right-to-Know Laws and Pollution Prevention Requirements, data 6 Aug. 1993) and Executive Order No. 12873 (Federal Acquisition, Recycling, and Waste Prevention, dated 20 Oct. 1993). A recent study found that the efficiencies of the oxidizer scrubbers during normal operations ranged from 70 percent to 99 percent. The new scrubber liquor starts with 1% hydrogen peroxide at a pH of 7 and the process control system adds hydrogen peroxide and potassium hydroxide to the scrubber liquor to maintain those initial conditions. The result is the formation of a solution of potassium nitrate, which is sold as a fertilizer. This report describes the equipment and procedures used to monitor and control the conversion of the scrubber liquor to fertilizer, while reducing the scrubber emissions.

Parrish, Clyde F.↗
DOE OSTI2015

German research and development for high level waste in light of the new site selection process - 15516

The German government decided 50 years ago, that radioactive waste is to be disposed of in Deep Geologic Repositories, preferably in a salt rock formation. Soon after, in 1967, research in the Asse salt mine was initiated. Since then substantial progress has been achieved in the development of the radioactive waste disposal programme in Germany. For a geologic repository for High Level Waste in salt a reference concept has been developed, which represented the radioactive waste management processes from transport of High Level Waste and Spent Nuclear Fuel to an interim storage site, waste conditioning and repackaging for disposal, to emplacement of the waste packages. The feasibility of the reference concept has been proven by demonstration tests for all relevant equipment: a pilot conditioning plant has been built as well as the main equipment for the entire transport chain including the shaft transport and emplacement technologies for heavy loads fulfilling strict requirements for nuclear and mining safety. Also the backfilling technology has been optimised for the purposes of a repository for radioactive waste. Finally, tests have been performed to verify thermo-mechanical models for the host rock. The demonstration tests have been performed to an extent which even would allow immediate licensing of the repository and the employed equipment. The Research and Development work was completed by further optimisation of the reference concept. Construction and operation of deep geologic repositories for low and intermediate level radioactive wastes in Germany benefited from the above mentioned but also stimulated the knowledge and experience build-up for the repositories for High Level Waste. Despite the well progressed work for a deep geologic repository in salt R and D work in Germany for already a long time also considered other host rock formations. While work for crystalline rock mainly consisted of relatively small contributions to international research projects due to the limited occurrence of suitable sites in Germany, projects and developments for repositories in clay formations have had an increasing contribution to the overall Research and Development work for radioactive waste repositories in Germany. In July 2013 a new site selection act was put into force, which set the initiating conditions for the German programme on radioactive waste management. Principally, a process was initiated to search for a site for a deep geologic repository for High Level Waste independent from earlier decisions. This means that a site shall be determined without predetermination by earlier decisions. Nevertheless, to enable a sound decision for a site selection it is necessary to be able draw back on the knowledge and experience from earlier activities. Otherwise, tedious learning processes would have to be experienced again. Since efforts to open up a site selection process again grew since the late 1990's projects had been implemented timely to capture existing knowledge. The paper at hand describes the achievements of R and D activities in Germany, the change of radioactive waste management policy and the endeavours to maintain the achievements. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2016

Valorization of Waste Lipids through Hydrothermal Catalytic Conversion to Liquid Hydrocarbon Fuels with in Situ Hydrogen Production

We demonstrate hydrothermal (300 degrees C, 10 MPa) catalytic conversion of real waste lipids (e.g., waste vegetable oil, sewer trap grease) to liquid hydrocarbon fuels without net need for external chemical inputs (e.g., H2 gas, methanol). A supported bimetallic catalyst (Pt-Re/C; 5 wt % of each metal) previously shown to catalyze both aqueous phase reforming of glycerol (a triacylglyceride lipid hydrolysis coproduct) to H2 gas and conversion of oleic and stearic acid, model unsaturated and saturated fatty acids, to linear alkanes was applied to process real waste lipid feedstocks in water. For reactions conducted with an initially inert headspace gas (N2), waste vegetable oil (WVO) was fully converted into linear hydrocarbons (C15-C17) and other hydrolyzed byproducts within 4.5 h, and H2 gas production was observed. Addition of H2 to the initial reactor headspace accelerated conversion, but net H2 production was still observed, in agreement with results obtained for aqueous mixtures containing model fatty acids and glycerol. Conversion to liquid hydrocarbons with net H2 production was also observed for a range of other waste lipid feedstocks (animal fat residuals, sewer trap grease, dry distiller's grain oil, coffee oil residual). These findings demonstrate potential for valorization of waste lipids through conversion to hydrocarbons that are more compatible with current petroleum-based liquid fuels than the biodiesel and biogas products of conventional waste lipid processing technologies.

09 BIOMASS FUELS↗
DOE OSTI2015

Thermal degradation of the solvent employed in the next-generation caustic-side solvent extraction process and its effect on the extraction, scrubbing, and stripping of cesium

As part of the ongoing development of the Next-Generation Caustic-Side Solvent Extraction (NGS) process, the thermal stability of the process solvent was investigated and shown to be adequate for industrial application. The solvent was thermally treated at 35 C over a period of 13 months whilst in dynamic contact with each of the aqueous phases of the current NGS process, namely SRS 15 (a highly caustic waste simulant), sodium hydroxide scrub solution (0.025 M), and boric acid strip solution (0.01 M). The effect of thermal treatment was evaluated by assessing batch extract/scrub/strip performance as a function of time, by monitoring the sodium extraction capacity of the solvent, and by analysis of the solvent using electrospray mass spectrometry. Current studies indicate that the NGS solvent should be thermally robust for a period of XXX months at the Modular Caustic-Side Solvent Extraction Unit (MCU) pilot plant located at Savannah River Site. Furthermore, the guanidine suppressor appears to be the solvent component most significantly impacted by thermal treatment of the solvent, showing significant degradation over time.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
NASA NTRS1990

Biomass production and nitrogen dynamics in an integrated aquaculture/agriculture system

A combined aquaculture/agriculture system that brings together the three major components of a Controlled Ecological Life Support System (CELSS) - biomass production, biomass processing, and waste recycling - was developed to evaluate ecological processes and hardware requirements necessary to assess the feasibility of and define design criteria for integration into the Kennedy Space Center (KSC) Breadboard Project. The system consists of a 1 square meter plant growth area, a 500 liter fish culture tank, and computerized monitoring and control hardware. Nutrients in the hydrophonic solution were derived from fish metabolites and fish food leachate. In five months of continuous operation, 27.0 kg of lettuce tops, 39.9 kg of roots and biofilm, and 6.6 kg of fish (wet weights) were produced with 12.7 kg of fish food input. Based on dry weights, a biomass conversion index of 0.52 was achieved. A nitrogen budget was derived to determine partitioning of nitrogen within various compartments of the system. Accumulating nitrogen in the hypoponic solution indicated a need to enlarge the plant growth area, potentially increasing the biomass production and improving the biomass conversion index.

Owens, L. P.↗
DOE OSTI2017

Air gasification of biogas-derived digestate in a downdraft fixed bed gasifier

Highlights: • Air gasification of digestate with high ash content was studied in detail. • Compared to original biomass, less tar was observed in digestate gasification process. • Improved molar ratio of H{sub 2}/CO potential for chemical synthesis was gained at 800 °C. • The by-products (biochar and ash) can be land applied as fertilizer. - Abstract: Digestate is a byproduct from biomass anaerobic digestion process. Gasification of dried digestate to produce gasesous product might be a promising route. In this work, air gasification of digestate with high ash content was performed in a downdraft fixed bed gasifier at temperature varying from 600 °C to 800 °C and air equivalence ratio (ER) ranging from 0.25 to 0.30. The ash melting properties were firstly detected by the Intelligent Ash Melting Point Test, and the by-products (biochar and ash) were analyzed. The results showed that no ash slagging was observed and therefore it is feasible to operate digestate gasification under 800 °C and ER ranging from 0.25 to 0.30. High temperature favored gas production, 800 °C is proposed for digestate gasification in the present study. ER with a medium value improved gas quality and cold gas efficiency (CGE), and the optimal LHV of 4.78 MJ/N m{sup 3} and CGE of 67.01% were obtained with ER of 0.28. High ER favored the increase of gas yield and decrease of tar concentration, and the optimal gas yield of 2.15 N m{sup 3}/kg and tar concentration of 1.61 g/N m{sup 3} were achieved with ER of 0.30. Improved molar ratio of H{sub 2}/CO varying from 1.03 to 1.08 was obtained at 800 °C, indicating gaseous product has the potential for chemical synthesis processes (1 < H{sub 2}/CO < 2). The byproducts biochar and ash could be applied on land as fertilizer.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2017

Incentivizing secondary raw material markets for sustainable waste management

Highlights: • An economic model of secondary raw material markets is presented. •Policies to enhance sustainable waste management at landfills are compared. • Correcting potential misperceptions of secondary raw materials seems quite promising. • Our theoretical model supports Circular Economy and landfilling mining initiatives. - Abstract: Notwithstanding several policy initiatives in many countries over a number of years, there remains a general sense that too much municipal solid waste is generated and that too much of the waste that is generated is landfilled. There is an emerging consensus that a sustainable approach to waste management requires further development of secondary raw material markets. The purpose of this paper is to propose a theoretical economic model that focuses upon this stage of a sustainable waste management program and explores policy options that could motivate efficiency in secondary raw material markets. In particular, we show how firm profit and social welfare optimizing objectives can be reconciled in a two-product market of waste management processes: landfilling and material reclamation. Our results provide theoretical support for building out recent Circular Economy initiatives as well as for the relatively recent emergence of landfill mining as a means for procuring secondary raw materials.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2018

Examples of Disposition Alternatives for WTP Solid Secondary Waste

The Hanford Waste Treatment and Immobilization Plant is planned to produce a variety of solid secondary wastes that will require disposal at the Integrated Disposal Facility on the Hanford Site. Solid secondary wastes include a variety of waste streams that are a result of waste treatment and processing activities.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2021

FCIC DFO--Moisture Management and Optimization in Municipal Solid Waste Feedstock through Mechanical Processing

The project goal is to produce densified product, focusing on characteristics of bulk density, durability, and moisture content, to reduce the cost of preprocessing. The objective of the project is to efficiently manage and handle the properties of MSW feedstock through INL-developed fractional milling, high moisture pelleting, and low temperature drying preprocessing technologies .

09 BIOMASS FUELS↗