Gaseous contaminant removal by adsorption. II
Breakthrough curve shape prediction during adsorption from gas stream in fixed bed adsorbers for trace contaminant control applied to activated charcoal
Merrill, R. P.↗
SEARCH · Engineering Papers
Results for “Breakthrough Curves”
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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A dispersion model approach to the preliminary design of adsorber beds for trace contaminants
It is shown that a dispersion model for the transport of a gas through a porous medium can be useful in the preliminary design of adsorber beds for the control of trace contaminants. The transmission function is considered, taking into account the transmission of 102-ppm acetaldehyde in helium flowing at various flow rates through an absorber bed. The experiments were conducted at a temperature of 25.0 C. Attention is given to a representation of the experimental breakthrough curve, the volume adsorption capacity, temperature studies, and correlations.
Madey, R.↗
Dynamic Modeling of Gaseous Multicomponent Trace Contaminant Adsorption
Activated carbon is a porous material in the Trace Contaminant Control (TCC) system that physically adsorbs volatile organic compounds (VOCs) generated within spacecraft and spacesuit environments. Several isotherm models exist to predict adsorption equilibria for processes involving multicomponent systems. This paper investigates the use of Ideal Adsorbed Solution Theory (IAST) for predicting multicomponent trace contaminant adsorption behavior using single-component isotherms based on potential theory. Developing simulations for experimental breakthrough curves will gauge the validity on the sizing and design of TCC architecture. Model results on predicting bed performance and roll-up effects are compared with available multicomponent test data.
Ideal Adsorbed Solution Theory (IAST)↗
Interpretation of Colloid-Homologue Tracer Test 10-03, Including Comparisons to Test 10-01
This presentation covers the interpretations of colloid-homologue tracer test 10-03 conducted at the Grimsel Test Site, Switzerland, in 2010. It also provides a comparison of the interpreted test results with those of tracer test 10-01, which was conducted in the same fracture flow system and using the same tracers than test 10-03, but at a higher extraction flow rate. A method of correcting for apparent uranine degradation in test 10-03 is presented. Conclusions are: (1) Uranine degradation occurred in test 10-03, but not in 10-01; (2) Uranine correction based on apparent degradation rate in injection loop in test 11-02 seems reasonable when applied to data from test 10-03; (3) Colloid breakthrough curves quite similar in the two tests with similar recoveries relative to uranine (after correction); and (4) Much slower apparent desorption of homologues in test 10-03 than in 10-01 (any effect of residual homologues from test 10-01 in test 10-03?).
54 ENVIRONMENTAL SCIENCES↗
Preliminary Collab Fracture Characterization Results from Flow and Tracer Testing Efforts
The EGS Collab project is developing ~10-20 m-scale field sites where fracture stimulation and flow models can be validated against controlled, small-scale, in-situ experiments. The first multi-well experimental site was established at the 4850 level in the Homestake Mine, where hydraulic fractures were created at an injection well drilled sub-horizontal from the drift. Ten tracer tests were conducted to characterize fracture flow pathways during the second hydraulic characterization test for 164’ Notch (October 24th to November 14th, 2018) during steady state injection of 400 ml/min at the injection well. Injected tracers include DNA, C-dots (fluorescein nano particles), fluorescein, rhodamine-b, sodium chloride, lithium bromide and cesium iodine. The tracers have been detected in three flowing wells located about 7.5 to 9 meters away from the injection interval. The tracer breakthrough curves from these locations have been adjusted to account for the residence time in the injection and production tubing. At the time of writing this paper, only the fluorescent C-dots, rhodamine-b and chloride have been analyzed for concentration vs time/volume at the production wells. Results from early testing have been re-analyzed as to the; amount and location of injected water recovery and the mass of tracer recovered.
15 GEOTHERMAL ENERGY↗
Fracture Tracer Injection Response to Pressure Perturbations at an Injection Well
The EGS Collab project constructed an approximately ten-meter scale field site where fracture stimulation and flow/transport models can be validated against controlled, in-situ experiments. The first multi-well experimental site was established at the 4850 level of the Stanford Underground Research Facility (SURF) in the Homestake Mine located in South Dakota. Hydraulic fractures were created at an injection well drilled sub-horizontal from the drift. A flow system was established in one set of fractures by injection water at approximately 400 ml/min between a set of packers 164 feet from the drift wall in the injection well through a hydraulically stimulated fracture. Injected water was recovered from five locations in 4 nearby wells. From the end of October to the middle of November of 2018, a series of fracture characterization tests were conducted using a series of 10 tracer tests (7 which used C-dot and chloride as conservative solute tracers) to assess the flow pathway in the stimulated fracture. The injected tracers were detected in three of the five water production locations where the total water recovery ranged from approximately 50 to 80% of the injected water depending on the day the test was being conducted. Analysis of a series of tracers during this two-week period suggest a large change in the flow fracture field occurred during this testing period. A comparison of the tracer breakthrough curves at the production well showed a marked decrease in the initial and peak concentration over time, whereas the OB well exhibited an increase in the initial and peak concentration arrival during this fracture characterization testing period. These changes are believed to be in response to a number of higher-pressure short-term injections at the injection well in early November (2nd to the 6th). Results of this testing suggest that the fracture flow pathways can be altered as a result of the pressure perturbations in the injection well on the integrity of adjacent monitoring wells. Results from the EGS Collab project will support the DOE Geothermal Technology Office FORGE and other EGS development efforts.
15 GEOTHERMAL ENERGY↗
Synthesis of Bismuth Functionalized Grapheme Oxide for Radioactive Iodine Gas Removal - 16114
Released radioactive iodine from nuclear reactors and nuclear severe accidents, such as those experienced at Chernobyl and Fukushima, is one of the most hazardous materials and can affect human health. Uptake of radioactive iodine from gaseous and aqueous waste, consisting of mainly organic forms such as methyl iodide and elemental iodine after reacting with organic matter in scrubber process, is a recent concern during nuclear power plant operation. In general, Triethylenediamine (TEDA) or KI-impregnated activated carbons, silver-loaded silica aerogels, and silver-loaded zeolite are used to remove radioactive iodine compounds. However, previous research has shown TEDA and KI-impregnated activated carbons to have some limitations for use in responding to severe accidents or in pressurized-water reactors, because they are easily burned up and the iodine removal efficiency of silver-loaded sorbents is greatly decreased at high temperatures. To improve the capability of synthesized sorbent material used in iodine gas removal, highly efficient sorbents for methyl and elemental iodine removal were prepared through the functionalization of graphene oxide (GO) with bismuth. GO was synthesized from natural graphite powder (99.95%) by the modified Hummers method, and then mixed with Bi(NO{sub 3}){sub 3}.5H{sub 2}O. After developing a sorbent for the removal of iodine, the synthesized sorbent was characterized using x-ray diffraction, a scanning electron microscope/energy dispersive spectrometer, and thermogravimetric analysis/differential scanning calorimetry, and the surface area of sorbents was determined using the BET-N{sub 2} adsorption method. Methyl iodine batch experiments were conducted for 7 days and elemental iodine gas adsorption experiments were conducted at high temperature (190 deg. C) using a carrier gas (air). The final concentration of iodine in batch and off-gas scrubber solutions (0.1 M NaOH) was analyzed using inductively coupled plasma mass spectrometry. The breakthrough curve and decontamination factor values were also investigated using bismuth-functionalized GO and the results were compared with Ag-zeolite, Sn-apatite, and activated carbon. (authors)
77 NANOSCIENCE AND NANOTECHNOLOGY↗
Capacity of ETS-10 supported carbon nanosorbent for removal of multicomponent from off-gas stream
Nuclear fission results in fission and activation products, some of which are volatile under the conditions of used nuclear fuel (UNF) reprocessing. Several volatile radionuclides are released into the atmosphere through offgas stream, which includes {sup 3}H, {sup 14}C, {sup 129}I and noble gases, Kr and Xe. {sup 129}I is a highly mobile and volatile contaminant. It has half-life period about 1.57 x 107 years that tends to bioaccumulate, concentrating in the thyroid glands and affecting bio-metabolism in humans. {sup 85}Kr is a chemically inert radioisotope with a half-life of 10.7 years that continuously accumulate in the environment. Control of emissions of these contaminants is necessary to comply with the stringent regulatory limits placed on their releases to protect human health and environment. Removal of these contaminants has been a challenge since the 1950's, and several methods including cryogenic distillation, fluorocarbon absorption, wet scrubbing, and adsorption have been employed. Currently, adsorption on porous solid sorbent shows the most promise results. Up to now, several sorbents such as silver impregnated mordenite, silver ETS-10, chalcogen based aerogels, and metal organic framework, MOFs have been developed for this purpose. Despite these advances, development of economical and highly active sorbents for complete removal and immobilization of volatile radioactive gases remains a key challenge in realizing advanced fuel cycles. Present research work is focused on the determination of the removal capacity of C'at'ETS-10 sorbent for a multicomponent (iodine and krypton) off-gas stream at ambient temperature. Our previously reported work showed that the 10 wt% C'at'ETS-10 sorbent was active for adsorption of krypton as well as iodine at ambient temperature and pressure. Therefore, 10 wt% C'at'ETS-10 sorbent was synthesized by wet-impregnation technique. The performance evaluation of the prepared nanosorbent was examined for the removal of iodine and krypton from the breakthrough curves obtained using bench scale experimental setup. ETS-10 supported carbon nanoparticles, C'at'ETS-10 nanosorbent was successfully synthesized by wet-impregnation technique. The 1/8 inch pelletized sorbent was used to minimize the pressure drop in adsorption column. The capacity of sorbent was found to be 0.143 mg g{sup -1} for krypton and 24.5 mg g{sup -1} for iodine. This experimental results indicates the C'at'ETS-10 is the effect sorbent for removal of multicomponent, krypton as well as iodine from the off-gas stream at ambient temperature. (authors)
38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗
Time-lapse electrical resistivity and induced polarization monitoring of a simulated ecosystem-scale coastal flooding experiment
Accurate estimation of the spatio-temporal variation in soil saturation and salt concentration is valuable for calibrating and evaluating Earth system models as well as detecting important eco-hydrological interactions. Such representative models play a vital role in investigating the stability of ecosystems facing changing hydrologic disturbance regimes. Ecosystem-scale field experiments are a useful way to capture hydrological disturbance and gain a deeper understanding of the complex mechanisms driving environmental changes. However, previous studies have not explored the use of quantitative imaging at a large spatial scale to reproduce breakthrough curves and inform system response and recovery following hydrologic disturbance events. Therefore, in this study, non-invasive geophysical methods were used to capture the spatio-temporal variation in subsurface saturation and salt concentrations during an ecosystem-scale coastal forest flooding experiment.
coastal↗
Conservative solute transport processes and associated transient storage mechanisms: Comparing streams with contrasting channel morphologies, land use and land cover
Abstract Land use within a watershed impacts stream channel morphology and hydrology and, therefore, in‐stream solute transport processes and associated transient storage mechanisms. This study evaluated transport processes in two contrasting stream sites where channel morphology was influenced by the surrounding land use, land cover, climate and geologic controls: Como Creek, CO, a relatively undisturbed, high gradient, forested stream with a gravel bed and complex channel morphology, and Clear Creek, IA, an incised, low‐gradient stream with low‐permeability substrate draining an agricultural landscape. We performed conservative stream tracer injections at these sites to address the following questions: (1) How does solute transport vary between streams with differing morphologies? and (2) How does solute transport at each stream site change as a function of discharge? We analysed in‐stream tracer time series data and compared results quantifying solute attenuation in surface and subsurface transient storage zones. Significant trends were observed in these metrics with varying discharge conditions at the forested site but not at the agricultural site. There was a broad range of transport mechanisms and evidence of substantial exchange with both surface and hyporheic transient storage in the relatively undisturbed, forested stream. Changing discharge conditions activated or deactivated different solute transport mechanisms in the forested site and greatly impacted advective travel time. Conversely in the simplified agricultural stream, there was a narrow range of solute transport behaviour across flows and predominantly surface transient storage at all measured discharge conditions. These results demonstrate how channel simplification inhibits available solute transport mechanisms across varying discharge conditions.
54 ENVIRONMENTAL SCIENCES↗
Nanoporous Boron Nitride as Exceptionally Thermally Stable Adsorbent: Role in Efficient Separation of Light Hydrocarbons
Here in this work, nanoporous boron nitride sample was synthesized with a Brunauer–Emmett–Teller (BET) surface area of 1360 m 2 /g and particle size 5–7 μm. The boron nitride was characterized with X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and electron microscopy (TEM and SEM). Thermogravimetric analysis (TGA) under nitrogen and air and subsequent analysis with XPS and XRD suggested that its structure is stable in air up to 800 °C and in nitrogen up to 1050 °C, which is higher than most of the common adsorbents reported so far. Nitrogen and hydrocarbon adsorption at 298 K and pressure up to 1 bar suggested that all hydrocarbon adsorption amounts were higher than that of nitrogen and the adsorbed amount of hydrocarbon increases with an increase in its molecular weight. The kinetics of adsorption data suggested that adsorption becomes slower with the increase in molecular weight of hydrocarbons. The equilibrium data suggested that that boron nitride is selective to paraffins in a paraffin–olefin mixture and hence may act as an “olefin generator”. The ideal adsorbed solution theory (IAST)-based selectivity for CH 4 /N 2 , C 2 H 6 /CH 4 , and C 3 H 8 /C 3 H 6 was very high and probably higher than the majority of adsorbents reported in the literature. IAST-based calculations were also employed to simulate the binary mixture adsorption data for the gas pairs of CH 4 /N 2 , C 2 H 6 /CH 4 , C 2 H 6 /C 2 H 4 , and C 3 H 8 /C 3 H 6 . Lastly, a simple mathematical model was employed to simulate the breakthrough behavior of the above-mentioned four gas pairs in a dynamic column experiment. The overall results suggest that nanoporous boron nitride can be used as a potential adsorbent for light hydrocarbon separation.
36 MATERIALS SCIENCE↗
Biporous Metal–Organic Framework with Tunable CO 2 /CH 4 Separation Performance Facilitated by Intrinsic Flexibility
Not Available
36 MATERIALS SCIENCE↗
EGS Collab Testbed 1: Tracer data tests
This file contains the first set of tracer data for the EGS Collab testbed. The first set of tracer tests were conducted during October-November, 2018. We have included tracer data for C-dots, chloride, fluorescein, and rhodamine-B. The details about the tracer test can be found in Background and Methods of Tracer Tests (Mattson et al. (2019)) (also included in this package). References Mattson, E.D., Neupane, G., Plummer, M.A., Hawkins, A., Zhang, Y. and the EGS Collab Team 2019. Preliminary Collab fracture characterization results from flow and tracer testing efforts. In Proceedings 44th Workshop on Geothermal Reservoir Engineering, edited, Stanford University, Stanford, California.
15 GEOTHERMAL ENERGY↗
Cesium Ion Exchange Testing Using Crystalline Silicotitanate with Hanford Tank Waste 241-AP-107
At the time of this testing, the Low-Activity Waste Pretreatment System (LAWPS) was to provide for the initial production of immobilized low-activity waste by feeding Hanford tank supernate from tank farms to the Hanford Tank Waste Treatment and Immobilization Plant (WTP) Low-Activity Waste (LAW) Facility for immobilization. Washington River Protection Solutions requested that Hanford tank waste collected from tank 241-AP-107 (hereafter called AP-107) be processed using conceived pretreatment steps (suspended solids removal by filtration, Cs removal by ion exchange) then vitrified. A small-scale test platform to demonstrate the solids filtration, Cs removal, and LAW vitrification was constructed and installed at Pacific Northwest National Laboratory. Bench-scale ion exchange testing with approximately 9 L of AP-107 supernate was conducted using crystalline silicotitanate (CST) ion exchange media. The IONSIV R9140-B CST was provided by Honeywell UOP, LLC in 2018 (Batch 2081000057). The ion exchange media was first tested with simulant and was previously described. This report describes the Cs ion exchange batch contact and column test results with the AP-107 tank waste. Batch contact testing helps to evaluate CST performance on tank waste supernate prior to processing it in the ion exchange columns. Batch contacts were performed with the waste at four Cs concentrations at a phase ratio of 200 (liquid volume to exchanger mass) with AP-107. The distribution coefficient (K d ) at the equilibrium condition of 8.57 µg Cs/mL (AP-107 feed condition) was determined to be 669 mL AP-107/g CST. With a CST bed density of 1.00 g/mL, this K d corresponded to a predicted 50% Cs breakthrough of 669 bed volumes (BVs). The Cs load capacity at the equilibrium feed condition was determined to be 7.5 mg Cs/g dry CST. The column testing was prototypic to the intended LAWPS operations in a lead-lag column format, although on a small-scale basis with 10-mL CST beds. The feed was processed downflow through the lead column and then through the lag column at ~2.2 BV/h. Loading continued until the lag column reached the WTP waste acceptance criteria (WAC) for receiving supernatant waste for vitrification (a function of the Na and 137 Cs concentrations). For AP-107, the WAC is 0.114% of the influent 137 Cs concentration; this required a Cs decontamination factor of 876. The Cs effluent from the lag column reached the WAC after processing ~410 BVs. To keep the subsequent product effluent below the WAC, a replacement lag column was prepared, the lead column was removed from service (after processing a total of 471 BVs), the lag column was put into the lead column position, and the replacement lag column was installed. Feed processing continued and after another ~290 BVs the Cs effluent from the lag column again exceeded the WAC. In both cases, the lead columns only reached 25% Cs breakthrough before removal. Although 50% Cs breakthrough was not reached, this value was estimated and averaged based on extrapolation of the loading curves (640 BVs) and agreed within 4% of the predicted 50% Cs breakthrough from batch contact test results (669 BVs). Table ES.1 summarizes the observed column performance and relevant Cs loading characteristics.
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
Photovoltaics as a terrestrial energy source. Volume 1: An introduction
Photovoltaic (PV) systems were examined their potential for terrestrial application and future development. Photovoltaic technology, existing and potential photovoltaic applications, and the National Photovoltaics Program are reviewed. The competitive environment for this electrical source, affected by the presence or absence of utility supplied power is evaluated in term of systems prices. The roles of technological breakthroughs, directed research and technology development, learning curves, and commercial demonstrations in the National Program are discussed. The potential for photovoltaics to displace oil consumption is examined, as are the potential benefits of employing PV in either central-station or non-utility owned, small, distributed systems.
Smith, J. L.↗
Comparative Study of Enhanced Geothermal System Supply Curves Across CONUS from Two Temperature Models Using the Renewable Energy Potential Model (reV)
Enhanced geothermal systems (EGS) have had recent breakthroughs within the geothermal sector. These breakthroughs are reflected in the National Renewable Energy Laboratory (NREL) 2024 Annual Technology Baseline and will result in updated EGS supply curves (i.e., the available resource capacity relative to cost). Our research uses NREL's Renewable Energy Potential (reV) model to compare EGS supply curves across the conterminous United States (CONUS) for two different temperature models: the Stanford temperature model (STM) and the Southern Methodist University temperature model (SMU). The reV model provides the levelized cost of energy (LCOE) at a consistent resolution across CONUS, taking into consideration transmission costs and constraints as well as technical exclusions pertaining to sensitive cultural, ecological, or infrastructure locations. In addition to a countrywide analysis of both models, we also conducted a regional analysis of Texas. We observed the STM had, on average, lower temperatures across different depths, resulting in slightly higher mean and median LCOEs as compared to the SMU temperature model at the same depths. In the regional analysis for Texas, however, when we compared only the common points between the two temperature models, the STM had lower median and mean LCOEs compared to SMU due to higher temperatures at depths greater than 5 km.
enhanced geothermal systems↗
Polymer concentration detection method based on fluorescent polymer to evaluate its retention and percolation
ABSTRACT A new fluorescent polymer was prepared by copolymerization of acrylamide and a modified rhodamine B (RhB). Fourier transformation infrared spectrometer and nuclear magnetic resonance confirmed the successful modification of RhB and the synthesis of fluorescent polymer. The rheological and fluorescence properties were studied by fluorospectrophotometer and rotational rheometer. The adsorption retention and percolation properties were evaluated by sand pack displacement experiments. The results indicated that fluorescence intensity revealed a distinct linear relationship with polymer concentration within a certain concentration range. High temperature and strong acidic conditions could diminish fluorescence intensity whereas formation water ions exerted inconsiderable influence on it. Rheological results manifested that fluorescent polymer can be used as polymer flooding agent. The sand pack displacement results proved the feasibility of using fluorescent polymer to detect polymer concentration. By this means, polymer breakthrough time and concentration variations could be confirmed. Based on the curves of injection pressure and polymer concentration, the percolation state and retention of polymer were able to be analyzed. Significantly, this work can provide support and guidance for the practical applications of fluorescent polymer. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136 , 47468.
Kang, Wanli↗
Radionuclide gas transport through nuclear explosion-generated fracture networks
Underground nuclear weapon testing produces radionuclide gases which may seep to the surface. Barometric pumping of gas through explosion-fractured rock is investigated using a new sequentially-coupled hydrodynamic rock damage/gas transport model. Fracture networks are produced for two rock types (granite and tuff) and three depths of burial. The fracture networks are integrated into a flow and transport numerical model driven by surface pressure signals of differing amplitude and variability. There are major differences between predictions using a realistic fracture network and prior results that used a simplified geometry. Matrix porosity and maximum fracture aperture have the greatest impact on gas breakthrough time and window of opportunity for detection, with different effects between granite and tuff simulations highlighting the importance of accurately simulating the fracture network. In particular, maximum fracture aperture has an opposite effect on tuff and granite, due to different damage patterns and their effect on the barometric pumping process. From stochastic simulations using randomly generated hydrogeologic parameters, normalized detection curves are presented to show differences in optimal sampling time for granite and tuff simulations. In conclusion, seasonal and location-based effects on breakthrough, which occur due to differences in barometric forcing, are stronger where the barometric signal is highly variable.
73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗