Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “Gas sample analysis”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 37 records · Page 2

Progress in developing laser based post irradiation examination infrastructure

To be able to understand the performance of reactor fuels and materials, irradiated materials must be characterized effectively and efficiently in high rad environments. This characterization work is performed remotely and in environments generally hostile to instrumentation. Laser based characterization techniques provide the ability to operate remotely and robustly in a hot-cell environment. Laser based instrumentation also can provide high spatial resolution suitable for scanning and imaging large areas. The INL is currently developing three laser based Post Irradiation Examination (PIE) stations for the Hot Fuel Examination Facility (HFEF) at the INL. These laser based systems will characterize irradiated materials and fuels. The characterization systems are the following: -) laser shock, -) laser based ultrasonic C-scan system and -) gas assay, sample and recharge system (GASR, up-grade to an existing system). The laser shock technique will characterize material properties and failure loads/mechanisms in various materials such as Light Water Reactor (LWR) fuel, plate fuel, and next generation fuel forms in high radiation areas. The laser shock-technique induces large amplitude shock waves to mechanically characterize interfaces such as the fuel-clad bond. As part of the laser shock system, a laser-based ultrasonic C-scan system will be used to detect and characterize de bonding caused by the application of the laser shock as well as performing classical non-destructive evaluation testing and imaging functions such as microstructure characterization, flaw detection and dimensional metrology. A spectroscopy capability can be added later as the salient components to perform Light Induced Breakdown Spectroscopy will be in place. Additional fiber ports in the feed-through will also enable future spectroscopic techniques to be efficiently installed and operated. The purpose of the GASR is to measure the pressure/volume of the plenum of an irradiated fuel element/capsule and obtain fission gas samples for analysis. The study of pressure and volume in the plenum of an irradiated fuel element/capsule and the analysis of fission gases released is important to understanding the performance of reactor fuels and materials. The main function of the laser in this application is to puncture the fuel rod or plate to allow the fission gas to escape and if necessary to weld the hole close. This system may also be used to measure the pressure/volume of other components (such as control blades) and obtain gas samples from these components for analysis. The GASR upgrade will match the functionality of the current system and provide these important functions on fuels made from current and future engineered materials. The GASR station will also have the inherent capability to perform cutting welding and joining functions within a hot-cell. The extra fiber ports built into the hot cell feed-through will also enable the efficient installation of future laser processing work benches. (authors)

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗

Mercury Source Zone Identification using Soil Vapor Sampling and Analysis

Development and demonstration of reliable measurement techniqes that can detect and help quantify the nature and extent of elemental mercury (Hg(0)) in the subsurface are needed to reduce certainties in the decision making process and increase the effectiveness of remedial actions. We conducted field tests at the Y-12 National Security Complex (NSC) in Oak Ridge, TN, to determine if sampling and analysis of Hg(0) vapors in the shallow subsurface (<0.3 m depth) can be used to as an indicator of the location and extent of Hg(0) releases in the subsurface. We constructed a rigid PVC pushprobe assembly, which was driven into the ground. Soil gas samples were collected through a sealed inner tube of the assembly and analyzed immediately in the field with a Lumex and/or Jerome Hg(0) analyzer. Time-series sampling showed that Hg vapor concentrations were fairly stable over time suggesting that the vapor phase Hg(0) was not being depleted and that sampling results were not dependent on the soil gas purge volume. Hg(0) vapor data collected at over 200 pushprobe locations at 3 different release sites correlated well to areas of known Hg(0) contamination. Vertical profiling of Hg(0) vapor concentrations conducted at 2 locations provided information on the vertical distribution of Hg(0) contamination in the subsurface. We concluded from our studies that soil gas sampling and analysis can be conducted rapidly and inexpensively at a large scale to help identify areas contaminated with Hg(0).

Watson, David B↗

Innovative approach to counterfeit and noncompliant refrigerant detection: A cost-effective, portable solution

The increasing prevalence of counterfeit and incompatible refrigerants presents significant risks to Heating, Ventilation, Air Conditioning, and Refrigeration (HVAC&R) systems, including compromised equipment performance, safety hazards, and non-compliance. This article details the development of a novel, cost-effective, and portable detection device designed to accurately verify refrigerants. The device utilizes a controlled gas sampling and analysis system within a sealed chamber, ensuring precise measurements while maintaining safety through a purging mechanism. The system features a high-sensitivity sensor integrated with an onboard control module that analyzes gas composition in real-time, providing feedback within a 2-minute duration. Laboratory validation demonstrated the device’s high accuracy (>95 % based on correct identification of compliant vs. non-compliant blends) in detecting unauthorized refrigerant blends. The projected cost of the product stands at ∼ $150, based on the retail pricing of individual components. Laboratory validation demonstrated the device’s high accuracy (>95 % for composition identification, 100 % rejection of tested counterfeit/incorrect blends) in detecting unauthorized refrigerant blends with a response time <2 min. The device correctly identified authentic R-454A/B/C blends and reliably rejected R-407F and closely related counterfeit mixtures. Key advantages include affordability, ease of use, rapid response time, and compatibility with a wide range of refrigerants. This solution supports compliance with regulatory frameworks, enhances safety in HVAC&R operations, and mitigates the risks associated with counterfeit refrigerants.

Counterfeit refrigerants↗

A Novel, Low-Cost, Portable Device for Counterfeit and Noncompliant Refrigerant Detection

The increasing prevalence of counterfeit refrigerants presents significant risks to Heating, Ventilation, Air Conditioning, and Refrigeration (HVACR) systems, including compromised equipment performance, safety hazards, and environmental non-compliance. This report details the development of a novel, cost-effective, and portable detection device designed to accurately identify counterfeit refrigerants. The device utilizes a controlled gas sampling and analysis system within a sealed chamber, ensuring precise measurements while maintaining safety through a purging mechanism. The system features a high-sensitivity sensor integrated with an onboard control module that analyzes gas composition in real-time, providing users with clear visual indicators for refrigerant authenticity.Laboratory validation demonstrated the device’s high accuracy (exceeding 95%) in detecting unauthorized refrigerant blends. Key advantages include affordability, ease of use, rapid response time, and compatibility with a wide range of refrigerants. This solution supports compliance with regulatory frameworks such as the American Innovation and Manufacturing (AIM) Act, enhances safety in HVACR operations, and mitigates the risks associated with counterfeit refrigerants. Future developments will focus on expanding refrigerant detection capabilities, integrating machine learning for enhanced accuracy, implementing cost-reduction strategies to improve accessibility and market adoption, and optimizing system packaging for enhanced field portability.

99 GENERAL AND MISCELLANEOUS↗

A Novel, Low-Cost, Portable Device for Counterfeit and Noncompliant Refrigerant Detection

The increasing prevalence of counterfeit refrigerants presents significant risks to Heating, Ventilation, Air Conditioning, and Refrigeration (HVACR) systems, including compromised equipment performance, safety hazards, and environmental non-compliance. This report details the development of a novel, cost-effective, and portable detection device designed to accurately identify counterfeit refrigerants. The device utilizes a controlled gas sampling and analysis system within a sealed chamber, ensuring precise measurements while maintaining safety through a purging mechanism. The system features a high-sensitivity sensor integrated with an onboard control module that analyzes gas composition in real-time, providing users with clear visual indicators for refrigerant authenticity. Laboratory validation demonstrated the device’s high accuracy (exceeding 95%) in detecting unauthorized refrigerant blends. Key advantages include affordability, ease of use, rapid response time, and compatibility with a wide range of refrigerants. This solution supports compliance with regulatory frameworks such as the AIM Act, enhances safety in HVACR operations, and mitigates the risks associated with counterfeit refrigerants. Future developments will focus on expanding refrigerant detection capabilities, integrating machine learning for enhanced accuracy, implementing cost-reduction strategies to improve accessibility and market adoption, and optimizing system packaging for enhanced field portability.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Consequence Analysis of Residual Water in a Storage Canister - 20484

Recent observations from projects sponsored under the DOE-Nuclear Energy Spent Fuel and Waste Disposition campaign show that residual free water, well above the 0.4 gm-moles that correspond to a 3 torr rebound pressure after a 30-minute hold following prototypic drying, may remain within SNF canisters used for long-term dry storage. Specifically, experimental observations in an Integrated Research Project showed subzero temperatures and a local pocket of frozen water in a mockup fuel assembly subjected to an industry practiced drying process. In gas sampling and analysis from the High Burnup (HBU) Demonstration project, using a fully loaded and dried SNF canister, indicated presence of 100 g of residual water had remained in the canister. The effects of residual water in terms of potential adverse impacts on the condition of the SNF and the canister internals during long-term dry storage has been rigorously evaluated to address inadvertent residual water contents. The impact of residual water on the fuel and canister internals, with a focus on the oxidation of the cladding and of postulated exposed (breached-clad) fuel, were evaluated using an integrated set of time-dependent environmental conditions with semi-empirical materials oxidation models. An 'integration model,' with coupled sub-models, developed and previously used by the Center for Nuclear Waste Regulatory Analysis (CNWRA), was applied and expanded with improved sub-models for water radiolysis, and for cladding and fuel oxidations. Cladding oxidation models for various alloys were developed using the rate constants for various cladding alloys in the dry storage temperature range. A burnup-dependent fuel oxidation model was developed; it accounted for inhibition effect of fission products on fuel oxidation rates. The potential for extension of the initial breach flaw (1 mm hole) was evaluated by two separate mechanics criteria. In the first case, a critical cladding strain criterion was used. In the second case, a critical stress intensity was used to evaluate stability of a planar axial flaw postulate. A failure condition exists when a sufficient amount of fuel oxidation (at the postulated breached-clad location) causes fuel pellet swelling to load the cladding to meet a mechanics criterion for flaw extension. The integration model's results provide the following insights. The radiolysis-generated oxygen is consumed with a partitioning between the cladding and the fuel. The extent of cladding oxidation is no more than 2 μm additional consumption of the cladding metal even with 10 moles of residual water, indicating that changes in cladding conditions due to water are expected to be negligible. The conditions for cladding failure (breach opening size extension) directly correlates with the extent of fuel oxidation. Fuel oxidation significant to extend the breach could occur even with 5.5 moles of residual water. The results indicate that fuel oxidation vis-a-vis cladding oxidation is more likely under a higher radiation field, i.e., when radiolytic decomposition of the residual water occurs in few years compared to several decades, and that the conditions to cause failure are increased with fuel and cladding temperatures approaching the peak storage temperature limit of 400 deg. C. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

Investigation and Applications of In-Source Oxidation in Liquid Sampling-Atmospheric Pressure Afterglow Microplasma Ionization (LS-APAG) Source

A liquid sampling-atmospheric pressure afterglow microplasma ionization (LS-APAG) source is presented for the first time, which is embedded with both electrospray ionization (ESI) and atmospheric pressure afterglow microplasma ionization (APAG) techniques. This ion source is capable of analyzing compounds with diverse molecule weights and polarities. An unseparated mixture sample was detected as a proof-of-concept, giving complementary information (both polarities and non-polarities) with the two ionization modes. It should also be noted that molecular mass can be quickly identified by ESI with clean and simple spectra, while the structure can be directly studied using APAG with in-source oxidation. The ionization/oxidation mechanism and applications of the LS-APAG source have been further explored in the analysis of nonpolar alkanes and unsaturated fatty acids/esters. A unique [M + O – 3H]{sup +} was observed in the case of individual alkanes (C{sub 5}–C{sub 19}) and complex hydrocarbons mixture under optimized conditions. Moreover, branched alkanes generated significant in-source fragments, which could be further applied to the discrimination of isomeric alkanes. The technique also facilitates facile determination of double bond positions in unsaturated fatty acids/esters due to diagnostic fragments (the acid/ester-containing aldehyde and acid oxidation products) generated by on-line ozonolysis in APAG mode. Finally, some examples of in situ APAG analysis by gas sampling and surface sampling were given as well. .

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

An Analysis of Abandoned Oil Well Characteristics Affecting Methane Emissions Estimates in the Cherokee Platform in Eastern Oklahoma

Anthropogenic activities increase methane emissions, contributing to greenhouse gas levels and adversely affecting the environment. Abandoned oil and gas wells potentially leak methane, but data are limited. We analyze methane emissions from abandoned wells (n = 179) in the Cherokee Platform in Oklahoma, a previously unaccounted basin, and compare emissions factors (EFs) to those in the Greenhouse Gas Inventory. We compare the contribution of various characteristics to the propensity for leakage. Higher emissions were observed with shallower wells and with unplugged wells. Plugged wells (n = 20) had an average EF of 96 ± 429 g/day and 65 ± 294 g/day for unplugged wells (n = 159). The majority of wells had no detectable leak. We calculated ethane EFs based on geochemical analysis of gas samples, finding higher EFs for unplugged (1.2 ± 5.5 g/day) versus plugged (0.9 ± 4.6 g/day) wells. The data indicate that in addition to the location of abandoned wells, physical characteristics are necessary to consider in estimating methane emissions.

58 GEOSCIENCES↗

Off-Gas Condensate and Cast Stone Analysis Results

A sample of off-gas condensate produced during a demonstration test of the direct-feed low-activity waste (DFLAW) Radioactive Waste Test Platform using waste retrieved from Hanford storage tank AP-105 waste was analyzed for major cations, anions, total cyanide, Resource Conservation and Recovery Act (RCRA) metals, selected radionuclides, and selected organic compounds. The remaining off-gas condensate was concentrated through evaporation and then used to produce Cast Stone waste forms. After the solid waste forms cured for 28 days, U.S. Environmental Protection Agency (EPA) Method 1311 (EPA 1992) Toxicity Characteristic Leach Procedure (TCLP) tests were conducted on two samples. The TCLP leachates were analyzed for RCRA metals, fluoride, and total cyanide. These chemical analyses were conducted to collect data on the waste form performance and to determine if the waste form will meet the disposal requirements of the Waste Control Specialists LLC (WCS) Federal Waste Disposal Facility (FWF) in Texas (WCS 2015) and the Integrated Disposal Facility at Hanford. The radionuclide results in the off-gas condensate were used to estimate concentrations in the Cast Stone waste forms; these estimates were then compared to Class C limits (30 TAC 336.362 Appendix E). With the possible exception of U-232, all measured radionuclides were determined to be below their respective Class C limits. Inductively coupled plasma-mass spectrometry (ICP-MS) was used to measure most of the radionuclides. It is not possible to differentiate the isotope measured at mass 232 between U 232 and Th-232 by mass spectroscopy. Class C limit comparisons were made by assuming two maximum possible scenarios; one in which all the isotope at mass 232 occurred as Th-232, and another assigning the entire mass contribution to U-232. If the isotope at mass 232 is all Th-232 then the waste form is well below its Class C limit; however, if the isotope at mass 232 is all U-232, then the Class C limit would be exceeded by more than a factor of 8. A chemical procedure to separate uranium from thorium followed by reanalysis by ICP-MS would be required to resolve this issue. A similar issue occurs at mass 238, which could be U-238 or Pu-238; however, in this case Pu-238 can be ruled out as a contributor to the isotope measured at mass 238 for the following reasons. Pu-238 has a half-life of 87.7 years and its daughter product (U-234) has a half-life of 2.5 × 105 years and a measured concentration of < 0.002 µg/L. If significant concentrations of Pu-238 were present in this waste, then the amount of measurable U 234 would have increased over the decades of storage in the Hanford tanks. Because this was not observed, it is concluded that the isotope measured at mass 238 is all U-238. A total of 68 organic compounds were targeted for analysis in the off-gas condensate. Of these compounds, only nine were measured above their respective minimum reportable concentration. These compounds were acenaphthene, acetone, n-butyl alcohol, p,p’-DDT, methyl ethyl ketone, nitrobenzene, o nitrophenol, pyridine, and toluene. Of the detectable compounds, only acenaphthene, acetone, o nitrophenol, and pyridine were above wastewater standards (40 CFR 268.48 - Universal Treatment Standards). None of the organic compounds exceeded the non-wastewater standards (40 CFR 268.48 - Universal Treatment Standards). Analysis of the TCLP leachates from the Cast Stone waste forms indicated that none of the analytes exceeded the Universal Treatment Standard and, in general, all were well below the standards.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

Conversion kinetics of container glass batch melting

Abstract Understanding the batch‐to‐glass conversion process is fundamental to optimizing the performance of glass‐melting furnaces and ensuring that furnace modeling can correctly predict the observed outcome when batch materials or furnace conditions change. To investigate the kinetics of silica dissolution, gas evolution, and primary foam formation and collapse, we performed X‐ray diffraction, thermal gravimetry, feed expansion tests, and evolved gas analysis of batch samples heated at several constant heating rates. We found that gas evolving reactions, foaming, and silica dissolution depend on the thermal history of the batch in a similar manner: the kinetic parameters of each process were linear functions of the square root of the heating rate. This kinetic similarity reflects the stronger‐than‐expected interdependence of these processes. On the basis of our results, we suggest that changes in furnace operating conditions, such as firing or boosting, influence the melting rate less than what one would expect without consideration of batch conversion kinetics.

Ueda, Nanako↗

G-LiHT Campaign Leaf Sample details & photos, March 2017: Puerto Rico

This data package includes details of leaves sampled for leaf spectra and chemistry from 5 sites in Puerto Rico, in March of 2017. Sunlit canopy and shaded leaves of 66 species were collected. Data for each sample includes species, leaf age, type of analysis (spectroscopy, gas exchange, chemistry), sample number and sample photographs. The data package includes a spreadsheet with sample information and a zip file of photographs (1.6 GB). This data was collected as part of the 2017 BNL–G-LiHT leaf spectra campaign. See related datasets for leaf spectral reflectance and transmittance, leaf mass area (LMA), and leaf chemistry. Note that leaf sample details are also included in related datasets.

54 ENVIRONMENTAL SCIENCES↗

Standardized Testing Program for Solid-State Hydrogen Storage Technologies

In the US and abroad, major research and development initiatives toward establishing a hydrogen-based transportation infrastructure have been undertaken, encompassing key technological challenges in hydrogen production and delivery, fuel cells, and hydrogen storage. However, the principal obstacle to the implementation of a safe, low-pressure hydrogen fueling system for fuel-cell powered vehicles remains storage under conditions of near-ambient temperature and moderate pressure. The choices for viable hydrogen storage systems at the present time are limited to compressed gas storage tanks, cryogenic liquid hydrogen storage tanks, chemical hydrogen storage, and hydrogen absorbed or adsorbed in a solid-state material (a.k.a. solid-state storage). Solid-state hydrogen storage may offer overriding benefits in terms of storage capacity, kinetics and, most importantly, safety. The fervor among the research community to develop novel storage materials had, in many instances, the unfortunate consequence of making erroneous, if not wild, claims on the reported storage capacities achievable in such materials, to the extent that the potential viability of emerging materials was difficult to assess. This problem led to a widespread need to establish a capability to accurately and independently assess the storage behavior of a wide array of different classes of solid-state storage materials, employing qualified methods, thus allowing development efforts to focus on those materials that showed the most promise. However, standard guidelines, dedicated facilities, or certification programs specifically aimed at testing and assessing the performance, safety, and life cycle of these emergent materials had not been established. To address the stated need, the Testing Laboratory for Solid-State Hydrogen Storage Technologies was commissioned as a national-level focal point for evaluating new materials emerging from the designated Materials Centers of Excellence (MCoE) according to established and qualified standards. Working with industry, academia, and the U.S. government, SwRI set out to develop an accepted set of evaluation standards and analytical methodologies. Critical measurements of hydrogen sorption properties in the Laboratory have been based on three analytical capabilities: 1) a high-pressure Sievert-type volumetric analyzer, modified to improve low-temperature isothermal analyses of physisorption materials and permit in situ mass spectroscopic analysis of the sample’s gas space; 2) a static, high-pressure thermogravimetric analyzer employing an advanced magnetic suspension electro-balance, glove-box containment, and capillary interface for in situ mass spectroscopic analysis of the sample’s gas space; and 3) a Laser-induced Thermal Desorption Mass Spectrometer (LTDMS) system for high thermal-resolution desorption and mechanistic analyses. The Laboratory has played an important role in down-selecting materials and systems that have emerged from the MCoEs.

08 HYDROGEN↗

Comparison of Impurities in Charcoal Sorbents Found by Neutron Activation Analysis

Abstract: Neutron activation of gas samples in a reactor often requires a medium to retain sufficient amounts of the gas for analysis. Charcoal is commonly used to adsorb gas and hold it for activation; however, the amount of activated sodium in the charcoal after irradiation swamps most signals of interest. Neutron activation analysis (NAA) was performed on several commonly available charcoal samples in an effort to determine the activation background. The results for several elements, including the dominant sodium element, are reported. It was found that ECN charcoal had the lowest elemental background, containing sodium at 2.65 ± 0.05 ppm, as well as trace levels of copper and tungsten.

activated carbon↗

Creating Accurate Methane Emission Inventories through Data-Driven Airborne Survey Strategies: Methods and Results from the Haynesville, Anadarko, and Permian Basins

Significantly reducing methane emissions from the oil and gas sector can decrease the rate of climate change over the next two decades, buying critical time for a global energy transition. However, emissions inventories that can be used by oil and gas operators and environmental regulators to identify optimal methane emission mitigation strategies are either based on conservative emission factor methods, or are inconsistent between studies due to differences in sampling strategies or survey technologies. We developed a new approach for methane emissions survey design that yields representative basinwide methane emissions inventories by surveying a subset of total assets in a given oil and gas basin. We identify several sampling and analysis principles, including large sample sizes, balanced sampling across oil and gas production, careful survey area definition, and a unified protocol for analysis, to be vital to producing an unbiased estimate of basin-scale emissions that can be reconciled with future studies. We further present results from deploying this strategy in two oil and gas producing regions in the United States: the Haynesville Basin in Texas and Louisiana, and the Woodford Shale in the Anadarko Basin in Oklahoma. Aerial surveys were performed in 2023 using the Insight M LeakSurveyor™ technology. Preliminary results from methane emissions detected by Insight M indicate that aerially detected emissions above roughly 30 kg(CH4)/hr by themselves contribute a fractional loss rate of 1.13% of gross gas production across oil and gas operations in the Haynesville Basin, with aerially detected emissions equivalent to 2.67% of gross gas production in the Woodford Shale. We supplement these aerial estimates with modeled emissions that are below the LeakSurveyor’s survey sensitivity using a recently published inventory-based model of methane emissions, which we update for our survey areas. We then combine our aerial detections with modeled emissions to yield methane emission distributions and inventories that incorporate the full range of potential methane emissions from the smallest to the largest. These results can be used to identify the most effective methane mitigation strategies for our study areas, and can be reconciled with future methane emissions surveys that use different technologies.

Sherwin, Evan (ORCID:0000000321804297)↗

Technical Proposal for Loading 3000 Gallon Crude Oil Samples from Field Terminal to Sandia Pressurized Tanker to Support US DOE/DOT Crude Oil Characterization Research Study

Sandia National Laboratories is seeking access to crude oil samples for a research project evaluating crude oil combustion properties in large-scale tests at Sandia National Laboratories in Albuquerque, NM. Samples must be collected from a source location and transported to Albuquerque in a tanker that complies with all applicable regulations for transportation of crude oil over public roadways. Moreover, the samples must not gain or lose any components, to include dissolved gases, from the point of loading through the time of combustion at the Sandia testing facility. In order to achieve this, Sandia designed and is currently procuring a custom tanker that utilizes water displacement in order to achieve these performance requirements. The water displacement procedure is modeled after the GPA 2174 standard “Obtaining Liquid Hydrocarbons Samples for Analysis by Gas Chromatography” (GPA 2014) that is used routinely by crude oil analytical laboratories for capturing and testing condensates and “live” crude oils, though it is practiced at the liter scale in most applications. The Sandia testing requires 3,000 gallons of crude. As such, the water displacement method will be upscaled and implemented in a custom tanker. This report describes the loading process for acquiring a ~3,000 gallon crude oil sample from commercial process piping containing single phase liquid crude oil at nominally 50-100 psig. This document contains a general description of the process (Section 2), detailed loading procedure (Section 3) and associated oil testing protocols (Section 4).

02 PETROLEUM↗

Analysis of Thermal and Chemical Effets on Negative Valve Overlap Period Energy Recovery for Low-Temperature Gasoline Combustion

A central challenge for efficient auto-ignition controlled low-temperature gasoline combustion (LTGC) engines has been achieving the combustion phasing needed to reach stable performance over a wide operating regime. The negative valve overlap (NVO) strategy has been explored as a way to improve combustion stability through a combination of charge heating and altered reactivity via a recompression stroke with a pilot fuel injection. The study objective was to analyze the thermal and chemical effects on NVO-period energy recovery. The analysis leveraged experimental gas sampling results obtained from a single-cylinder LTGC engine along with cylinder pressure measurements and custom data reduction methods used to estimate period thermodynamic properties. The engine was fueled by either iso-octane or ethanol, and operated under sweeps of NVO-period oxygen concentration, injection timing, and fueling rate. Gas sampling at the end of the NVO period was performed via a custom dump-valve apparatus, with detailed sample speciation by in-house gas chromatography. The balance of NVO-period input and output energy flows was calculated in terms of fuel energy, work, heat loss, and change in sensible energy. Experiment results were complemented by detailed chemistry single-zone reactor simulations performed at relevant mixing and thermodynamic conditions, with results used to evaluate ignition behavior and expected energy recovery yields. For the intermediate bulk-gas temperatures present during the NVO period (900-1100 K), weak negative temperature coefficient behavior with iso-octane fueling significantly lengthened ignition delays relative to similar ethanol fueled conditions. Faster ethanol ignition chemistry led to lower recovered fuel intermediate yields relative to similar iso-octane fueled conditions due to more complete fuel oxidation. From the energy analysis it was found that increased NVO-period global equivalence ratio, either from lower NVOperiod oxygen concentrations or higher fueling rates, in general led to a greater fraction of net recovered fuel energy and work as heat losses were minimized. These observations were supported by complementary single-zone reactor model results, which further indicated that kinetic time-scales favor chemical energy-consuming exothermic oxidation over slower endothermic reformation. Nonetheless, fuel energy recovery close to the thermodynamic equilibrium solution was achieved for baseline conditions that featured 4% NVO-period oxygen concentration.

ethanol↗

Compendium of Phase-I Mini-SHINE Experiments

Argonne National Laboratory is assisting SHINE Medical Technologies in their efforts to develop the technology to become a domestic Mo-99 producer using low-enriched uranium (LEU). Mini-SHINE experiments are being performed with the high-current electron linear accelerator (linac) at Argonne. The target solution is a 90-150 g-U/L LEU uranyl sulfate at pH 1. In Phase 1, the convertor was tantalum with a maximum beam power on the convertor of 10 kW, and the target solution was limited to 5 L. This configuration generated a peak fission power density of 0.05 W/mL. Nine experiments were performed between February and October 2015. Results are reported and discussed for each experiment regarding the off-gas analysis system, the sampling and Mo-recovery operation, and the Mo-product concentration and purification system. In Phase 2, the convertor will be depleted uranium; beam power will increase to 20 kW; and the solution volume will be 18 L. This configuration will generate a fission power density of up to 1 W/mL.

43 PARTICLE ACCELERATORS↗

DFLAW Glass and Feed Qualifications to Support WTP Start-Up and Flow-Sheet Development (Final Report, Rev. 0)

In each test, a distinct feed composition was used to determine the effects of feed composition changes on the retention of technetium and other species as detailed in the Test Plan for this work. Key operating parameters such as the glass temperature (nominally 1150°C) were held constant to investigate the effect of each new feed composition on the retention of technetium. The processing rate was maintained at ≈2,250 kg/m 2 /day of glass, which corresponds to the “stretch-goal” rate of 22.5 MT/day specified by ORP for the WTP LAW melter, or ≈2,000 kg/m 2 /day of glass, which corresponds to the enhanced baseline specified by ORP for the WTP LAW melter (as compared to the nominal 1500 kg/m 2 /day). The bubbling rate was adjusted to achieve a near-complete cold-cap (90-100% of melt surface covered with feed). Quantitative measurements of glass production rates, melter operating conditions (temperatures, pressures, power, flows, etc.), gaseous emissions by Fourier Transform Infrared Spectroscopy (FTIR), and particulate emissions using Environmental Protection Agency (EPA) methods were made for each test. Discharged and melt pool glass samples were inspected for formation of any salt phases and analyzed for chemical composition, including technetium content. Samples of the process fluids from each of the off-gas treatment system components were collected and analyzed. Following each test, the off-gas system was partially disassembled and extensively sampled for any residual feed components residing within the off-gas system. Sampling and analysis during and subsequent to each test was intended to be sufficient for supporting a mass balance for all constituents of interest and particularly technetium, rhenium, iodine, sulfur, chlorine, and fluorine. Additional sampling and analysis of evaporator concentrates and condensates was conducted for various organic compounds.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗