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At least 73 records · Page 4

Development and testing of a continuous maritime monitor for radionuclide aerosols

Monitoring airborne concentrations of radionuclide activity may provide a timely warning to sea-based assets to avoid contamination from a radioactive plume. The development and testing of an automated aerosol monitoring system that can capture and detect radioactive particulate from marine air is presented. A custom electrostatic precipitator (ESP) was designed to capture particulate onto a reusable collection media. The collection efficiency of the ESP system for radon progeny was determined to be ~23%. A conservative calculation of the minimum detectable concentration of 214 Bi was estimated as 0.3-8 Bq/m 3 . The system was demonstrated in continuous operation, without consumables and limited maintenance, in a marine environment at the PNNL campus in Sequim, Washington. In conclusion, a successful 2-month deployment indicates the feasibility of the approach for continuous maritime monitoring for radionuclide aerosols.

Moore, Michael E. [Pacific Northwest National Labo↗

Electrochemical study of Aluminum-Fly Ash composites obtained by powder metallurgy

In this paper, two different ASTM C 618 Class C fly ashes (FA) were used for the production of aluminum metal matrix composites (MMCs) using powder metallurgy (PM) technology. Calcareous FAs were sampled from the electrostatic precipitators of two different lignite-fired power stations: from Megalopolis, Southern Greece (MFA) and from Kardia, Northen Greece (KFA), under maximum electricity load. FAs were milled in order to reduce the mean particle diameter and Aluminum-FA composites containing 10% and 20% of FA were then prepared and compacted. The green products were sintered for 2 h at 600 Degree-Sign C. Sintered Al-FA MMCs showed increased hardness and wear resistance suggesting their possible use in industrial applications for example in covers, casings, brake rotors or engine blocks. As most possible industrial applications of MMCs not only require wear resistance, but also corrosion resistance in different mild aggressive medias, this paper aims to study the electrochemical behavior of FA MMCs in order to evaluate their corrosion resistance. The morphology and chemical composition of the phases in the Aluminum-FA composite samples were investigated using Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDXS). Moreover, topographic and Volta potential maps were acquired by Scanning Kelvin Probe Force Microscopy (SKP-FM). Volta potential maps provide information about the electrochemical behavior of the different phases in absence of electrolyte. The electrochemical behavior was investigated by Open Circuit Potential measurements and potentiodynamic polarization, while the corrosion mechanisms were studied by SEM observations after different times of immersion in a mild corrosive medium. In all cases it could be stated that the addition of the FA particles into the Al matrix might cause an increase of the hardness and mechanical properties of the pure aluminum but deteriorates the corrosion resistance. The degradation phenomena occurring on the FA containing samples might be related to the following mechanisms: 1) Partial detachment or dissolution of the FA soluble phases, in particular based on Si, Fe and Ca; 2) dissolution of the Al matrix surrounding the FA particles due to crevice corrosion; 3) Al localized dissolution due to galvanic coupling between the Fe-rich intermetallics and the matrix. - Highlights: Black-Right-Pointing-Pointer Aluminum metal matrix composites containing two types of fly ashes have been characterized. Black-Right-Pointing-Pointer The microstructure and the electrochemical behavior have been studied using different techniques. Black-Right-Pointing-Pointer The addition of FA deteriorates the corrosion resistance of the aluminum. Black-Right-Pointing-Pointer Degradation mechanisms: galvanic coupling, crevice corrosion, detachment of FA particles.

36 MATERIALS SCIENCE↗

Red Mud Catalytic Pyrolysis of Pinyon Juniper and Single-Stage Hydrotreatment of Oils

Pinyon juniper biomass feedstocks, which cover a large acreage of rangeland in the western United States, are being eradicated and, therefore, considered as a convenient biomass feedstock for biofuel production. Pinyon juniper whole biomass (wood, bark, and leaves) were pyrolyzed in a pilot-scale bubbling fluidized-bed reactor at 450 °C, and the noncondensable gases were recycled to fluidize the reactor. Red mud was used as the in situ catalyst for the pyrolysis of the pinyon juniper biomass. The pyrolysis products were condensed in three stages, and products were analyzed for physicochemical properties. The condenser oil formed two phases with the aqueous fraction, whereas the electrostatic precipitator oils formed a single phase. The oil pH was 3.3; the higher heating value (HHV) was 28 MJ/kg; and the viscosity was less than 100 cP. There was a direct correlation between the viscosity of the oils and the alcohol/ether content of the oils, and this was also related to the aging rate of the oils. The catalytic pyrolysis oils were hydrotreated in a continuous single-stage benchtop hydrotreater to produce hydrocarbon fuels with a density of 0.80$-$0.82 cm 3 /g. The hydrotreater ran continuously for over 300 h with no significant catalyst deactivation or coke formation. This is the first time that such a long single-stage hydrotreatment has been demonstrated on biomass catalytic pyrolysis oils.

biomass↗

The transport dynamics of tens of micrometer-sized water droplets in RF atmospheric pressure glow discharges

Abstract Charging of particles having diameters of tens of microns has been extensively studied at atmospheric pressure in the context of, for example, electrostatic precipitators where the focus was on unipolar charging. The ambipolar charging of particles in atmospheric pressure plasmas, and of droplets in particular, has received less attention. The plasma activation of droplets is of interest for water purification, fertilizer production and materials synthesis, all of which depend on the transport of the droplets through the plasma, which in turn depends on their charging. In this paper, we report on the transport dynamics of water droplets, tens of microns in diameter, carried by the gas flow through an atmospheric pressure radiofrequency glow discharge sustained in helium. The droplets pass through the plasma with minimal evaporation and without reaching the Rayleigh limit. The droplet trajectory in the presence and absence of the plasma provides insights on the forces acting on the droplet. The measurements were analyzed using results from a three-dimensional fluid model and a two-dimensional plasma hydrodynamics model. We found that the transport dynamics as the droplet enters and leaves the plasma are due to differential charging of the droplet in the plasma gradients of the bounding sheaths to the plasma.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗

Subtask 4.8 - Fate and Control of Mercury and Trace Elements

The Center for Air Toxic Metals® (CATM®) Program at the Energy & Environmental Research Center (EERC) continues to focus on vital basic and applied research related to the fate, behavior, measurement, and control of trace metals, especially mercury, and the impact that these trace metals have on human health and the environment. For years, the CATM Program has maintained an international perspective, performing research and providing results that apply to both domestic and international audiences, with reports distributed in the United States and abroad. In addition to trace metals, CATM’s research focuses on other related emissions and issues that impact trace metal releases to the environment, such as SO x , NO x , CO 2 , ash, and wastewater streams. Of paramount interest and focus has been performing research that continues to enable the power and industrial sectors to operate in an environmentally responsible manner to meet regulatory standards. The research funded by the U.S. Department of Energy’s (DOE’s) National Energy Technology Laboratory (NETL) through CATM has allowed significant strides to be made to gain a better understanding of trace metals and other emissions, improve sampling and measurement techniques, fill data gaps, address emerging technical issues, and develop/test control technologies that allow industry to cost-effectively meet regulatory standards. The DOE NETL–CATM research specifically focused on the fate and control of mercury and trace elements in power systems that use CO 2 control technologies, such as oxycombustion and gasification systems, which are expected to be among those technologies that will be used to address climate change issues. In addition, research addressed data gaps for systems that use conventional and multipollutant control technologies, such as electrostatic precipitators, selective catalytic reduction units, flue gas desulfurization systems, and flue gas-conditioning methods, to understand mercury interactions, develop better control strategies and, in some cases, prevent mercury from being reemitted. This research also addressed stakeholder concerns and questions related to sampling and analytical methods for mercury, especially for continuous mercury monitors and sorbent trap methods for future compliance. Advancements were made toward the development of a much simpler dry-based method for measurement of halogens and trace metals. Finally, this research resulted in significant outcomes related to mercury and selenium concentrations in freshwater fish and how it is associated with other elements, thereby potentially impacting health; this has greatly enhanced the understanding of the second-order mechanism of mercury toxicity. The outcomes of this research have been shared with stakeholders in various domestic and international forums, working groups, conferences, educational settings, and published documents, with information available and accessible to those most impacted or interested in timely and current results on toxic metals. This subtask was funded through the EERC–DOE Joint Program on Research and Development for Fossil Energy-Related Resources Cooperative Agreement No. DE-FC26-08NT43291.

54 ENVIRONMENTAL SCIENCES↗

Technetium Retention in WTP LAW Glass with Recycle Flow-Sheet: DMIO Melter Testing

Melter tests were conducted to determine the retention of technetium and other volatiles in glass while processing simulated Low Activity Waste (LAW) streams through a DM10 melter equipped with a prototypical off-gas system that concentrates and recycles fluid effluents back to the melter feed. To support these tests, an existing DM10 system installed at Vitreous State Laboratory (VSL) was modified to add the required recycle loop. Based on the Hanford Tank Waste Treatment and Immobilization Plant (WTP) LAW off-gas system design, suitably scaled versions of the Submerged Bed Scrubber (SBS), Wet Electrostatic Precipitator (WESP), and TLP vacuum evaporator were designed, built, and installed into the DM10 system. Process modeling was used to support this design effort and to ensure that issues associated with the short half life of the 99m Tc radioisotope that was used in this work were properly addressed and that the system would be capable of meeting the test objectives. In particular, this required that the overall time constant for the system was sufficiently short that a reasonable approach to steady state could be achieved before the 99m Tc activity dropped below the analytical limits of detection. The conceptual design, detailed design, flow sheet development, process model development, Piping and Instrumentation Diagram (P&ID) development, control system design, software design and development, system fabrication, installation, procedure development, operator training, and Test Plan development for the new system were all conducted during this project. The new system was commissioned and subjected to a series of shake-down tests before embarking on the planned test program. Various system performance issues that arose during testing were addressed through a series of modifications in order to improve the performance and reliability of the system. The resulting system provided a robust and reliable platform to address the test objectives.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

Stabilization of Bio-Oil Fractions for Insertion into Petroleum Refineries

This project is part of a collaboration effort between Iowa State University (ISU), University of Oklahoma (OK) and Pacific Northwest National Laboratory (PNNL). The purpose of this project is to stabilize bio-oil fractions and improve their suitability for insertion into petroleum refineries. Bio-oil from fast pyrolysis of biomass is a complex mixture of unstable organic compounds. These organic compounds react under standard room conditions resulting in increases in bio-oil viscosity and water content – both detrimental for bio-oil storage and transportation. This study employed fractionation and upgrading systems to improve the stability of bio-oil. The fractionation system consists of a series of condensers, and electrostatic precipitators designed to separate bio-oil into five fractions: soluble carbohydrates (SF1&2), clean phenolic oligomers (CPO) and middle fraction (SF3&4), light oxygenates (SF5). A two-stage upgrading process was designed to process bio-oil stage fractions into stable products that can be inserted into a refinery. In the upgrading system, heavy and middle bio-oil fractions were upgraded into stable oil via cracking and subsequent hydrodeoxygenation. The light oxygenate fraction was steam reformed to provide a portion of requisite hydrogen for hydroprocessing. Hydrotreating and hydrocracking employed hydrogen from natural gas, fuel gas and light oxygenates reforming. The finished products from this study consist of gasoline- and diesel-blend stock fuels.

09 BIOMASS FUELS↗

Integrating Waste Heat from CO 2 Removal and Coal-Fired Flue Gas to Increase Plant Efficiency

In project DE-FE0007525, Southern Company Services demonstrated heat integration methods for the capture and sequestration of carbon dioxide produced from pulverized coal combustion. A waste heat recovery technology (termed High Efficiency System) from Mitsubishi Heavy Industries America was integrated into an existing 25-MW amine-based CO 2 capture process (Kansai Mitsubishi Carbon Dioxide Recovery Process®1) at Southern Company’s Plant Barry to evaluate improvements in the energy performance of the pulverized coal plant and CO 2 capture process. The heat integration system consists of two primary pieces of equipment: (1) the CO 2 Cooler which uses product CO 2 gas from the capture process to heat boiler condensate, and (2) the Flue Gas Cooler which uses air heater outlet flue gas to further heat boiler condensate. Both pieces of equipment were included in the pilot system. The pilot CO 2 Cooler used waste heat from the 25-MW CO 2 capture plant (but not always from product CO 2 gas, as intended). The pilot Flue Gas Cooler used heat from a slipstream of flue gas taken from downstream of Plant Barry’s air heater. The pilot also included a 0.25-MW electrostatic precipitator. The 25-MW High Efficiency System operated for approximately six weeks over a four month time period in conjunction with the 25-MW CO 2 capture facility at Plant Barry. Results from the program were used to evaluate the technical and economic feasibility of full-scale implementation of this technology. The test program quantified energy efficiency improvements to a host power plant that could be realized due to the High Efficiency System. Through the execution of this project, the team verified the integrated operation of the High Efficiency System and Kansai Mitsubishi Carbon Dioxide Recovery Process®. The ancillary benefits of the High Efficiency System were also quantified, including reduced water consumption, a decrease in toxic air emissions, and better overall air quality control systems performance.

20 FOSSIL-FUELED POWER PLANTS↗

Evaluation of Immobilizing Secondary Waste from a Proposed Treatment Process for Hanford WTP LAW Melter Condensate

The off-gas system in the Low Activity Waste (LAW) vitrification facility at the Hanford Waste Treatment and Immobilization Plant (WTP) will generate an aqueous condensate recycle stream. Two unit operations generate this condensate, a Submerged Bed Scrubber and a Wet Electrostatic Precipitator (LAW SBSWESP condensate). The expected disposition of this stream during baseline operations is to send it to the WTP Pretreatment Facility, where it will be blended with LAW, concentrated by evaporation and recycled to the LAW vitrification facility again. The primary reason to recycle this stream is to immobilize the semivolatile 99 Tc isotope into the glass. During the Direct Feed Low Activity Waste (DFLAW) portion of the mission, the condensate is sent to the Effluent Management Facility (EMF) where it is evaporated then recycled to the LAW facility where the evaporated condensate is combined with the LAW feed from the pretreatment system.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

Subtask 2.6 – Optimization of Aerosol Mitigation Technology for Postcombustion CO 2 Capture

Growing concerns over the impact of CO 2 emissions from combustion sources on global climate change have prompted numerous research and development projects aimed at developing cost-effective technologies for CO 2 capture. One family of technologies being demonstrated at pilot and full scale globally is postcombustion CO 2 capture (PCCC) systems that employ amine-based solvents. The captured CO 2 can be compressed and permanently stored underground or used for enhanced oil recovery (EOR). The proximity of North Dakota’s lignite-fired fleet of power plants to potential CO 2 storage options creates a unique atmosphere for PCCC within the state. However, the aerosols present in lignite flue gas present a challenge for large-scale PCCC at North Dakota power plants. Aerosols can negatively impact the long-term performance of amine-based solvents for CO 2 capture. Amine-based solvents are volatile, and aerosols provide nucleation sites where amine vapors can condense. Because aerosols cannot be easily captured at the column outlet using conventional technologies, the amine-laden aerosols escape the system and lead to accelerated solvent losses. Moreover, aerosol components can chemically react with amines to form degradation products that can permanently deactivate the amine, cause fouling, and lead to hazardous emissions. Many of the elements that have been shown to catalyze solvent degradation are present in lignite coals and can exacerbate solvent replacement economics. Understanding this issue is critical to the implementation of solvent-based CO 2 capture systems as applied to lignite-fired generation systems. The Energy & Environmental Research Center (EERC) designed and carried out this project to optimize aerosol mitigation technology for PCCC at a lignite-fired power plant. To meet the goal of this project, the following objectives were identified: Determine the effectiveness of a wet electrostatic precipitator (WESP) on collection of aerosols at a low-rank coal-fired power station. Determine the impact of aerosols on the efficiency and degradation products of amine-based carbon capture systems fired with low-rank fuels. Work was conducted at Minnkota Power Cooperative’s (MPC’s) Milton R. Young (MRY) Station Unit 2 using a slipstream of flue gas from the outlet of the plant’s flue gas desulfurization (FGD) unit. To gather initial data for sizing and specifying a WESP for this system, a temporary pilot-scale WESP was rented and installed on-site. Several different conditions were tested to examine the impact of flow rate, voltage, and current on WESP performance. The WESP was effective at removing large particulate (>200 nm) but caused an increase in fine particulate (<75 nm). Fine particulate material at the inlet and outlet of the WESP was collected, analyzed, and showed that crystalline sulfates carried over from the plant’s FGD unit were being converted to fine aerosols and SO 2 was being converted to SO 3 through the WESP. Additionally, the high moisture content of the flue gas stream at this sample location also contributed to an overall increase in aerosol mass under some of the test conditions. Using the results from the rented WESP, the project team installed a smaller-scale WESP upstream of the EERC’s slipstream CO 2 capture system. Flue gas was routed through a pilot-scale FGD unit to remove SO 2 to very low levels (~1 ppm) and then through a direct contact cooler (DCC) to further cool the gas and to remove moisture. The gas exiting the DCC was then routed through the new WESP before passing to the CO 2 absorber columns. Fluor’s amine-based solvent was used to scrub CO 2 from the slipstream through a set of two absorber columns. The rich solvent was regenerated in a stripper column by heating to drive off captured CO 2 . The system operated using a catch-and-release method where the CO 2 was separated to provide data on the process, but the captured CO 2 was released back into the host site stack. Aerosols and sulfur species were measured at multiple locations throughout the pilot-scale system. The inlet FGD and DCC removed much of the particulate matter and gaseous sulfur upstream of the WESP. With this configuration, the WESP achieved >95% particulate capture. The new WESP did not show any of the increases in SO 3 or other aerosol species that had been consistently observed with the larger-scale WESP installed immediately downstream of the plant’s full-scale FGD unit. Particulate samples captured and analyzed from the WESP inlet did not show any presence of crystalline sulfate materials, indicating that the pilot-scale FGD and DCC were efficient at reducing carryover from the plant’s full-scale FGD unit. A set of parametric tests were conducted on the new WESP to assess the impacts of flow rate, voltage, number of online WESP fields, and gas-phase sulfur content on aerosol and sulfur transformations. The results showed that the WESP performed similarly well at all sets of conditions. Sulfur and particulate matter exiting the WESP were further reduced through the absorber column as the amine-based solvent captured some of the residual contaminants. Solvent analysis showed that these species were slowly concentrating in the solvent over the duration of the test. When the WESP was taken offline and the sulfur slip through the FGD allowed to rise, the sulfate content in the solvent rose sharply, showing that the extra FGD and WESP were effective at reducing sulfate and cation uptake. This would be expected to extend amine-based solvent life by slowing the formation of heat-stable salts and other degradation products. This subtask was cofunded through the EERC–U.S. Department of Energy Joint Program on Research and Development for Fossil Energy-Related Resources Cooperative Agreement No. DE-FE0024233. Nonfederal funding was provided by the North Dakota Industrial Commission and MPC.

01 COAL, LIGNITE, AND PEAT↗

Acetonitrile Destruction in ETF Feed Solutions by UV/OX and Persulfate (Final Report)

The Hanford Site Effluent Treatment Facility (ETF) currently treats aqueous waste streams that include condensates from the 242-A evaporator, leachate from the Environmental Restoration Disposal Facility (ERDF), as well as laboratory wastes and, in the future, will treat liquid effluents from the Hanford Waste Treatment and Immobilization Plant (WTP) and Integrated Disposal Facility (IDF) leachate. Liquid effluents from the WTP will have significant concentrations of acetonitrile. Acetonitrile is formed by reaction of nitrates and sugar in the WTP low activity waste (LAW) melters and is prevalent in the submerged bed scrubber (SBS) and wet electrostatic precipitator (WESP) liquid effluents from WTP off-gas treatment. When these liquids are concentrated in the WTP Effluent Management Facility (EMF) evaporator in the direct feed low activity waste (DFLAW) flow-sheet, testing has shown that the majority of the acetonitrile partitions to the evaporator condensate. Since the evaporator condensate is directed to the ETF, this creates a potential issue with the ETF waste acceptance criteria and, specifically, the ETF Delisting Modification treatability envelope limits. Consequently, there is a need to assess possible mitigation approaches, one of which involves identification and assessment of potential treatment processes to destroy the acetonitrile, which is the subject of the present report.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

Testing of UV Oxidation Process for Acetonitrile Destruction

The Hanford Site Effluent Treatment Facility (ETF) currently treats aqueous waste streams that include condensates from the 242-A evaporator, leachate from the Environmental Restoration Disposal Facility (ERDF), as well as laboratory wastes and, in the future, will treat liquid effluents from the Hanford Waste Treatment and Immobilization Plant (WTP) and Integrated Disposal Facility (IDF) leachate. Liquid effluents from the WTP will have significant concentrations of acetonitrile. Acetonitrile is formed by reaction of nitrates and sugar in the WTP low activity waste (LAW) melters and is prevalent in the submerged bed scrubber (SBS) and wet electrostatic precipitator (WESP) liquid effluents from WTP off-gas treatment. When these liquids are concentrated in the WTP Effluent Management Facility (EMF) evaporator in the direct feed low activity waste (DFLAW) flow-sheet, testing has shown that the majority of the acetonitrile partitions to the evaporator condensate. Since the evaporator condensate is directed to the ETF, this creates a potential issue with the ETF waste acceptance criteria and, specifically, the ETF Delisting Modification treatability envelope limits. Consequently, there is a need to assess possible mitigation approaches, one of which involves identification and assessment of potential treatment processes to destroy the acetonitrile, which is the subject of the present report.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

Final Report on Aerosol Pretreatment Technology Performance and Benchmarking

Solvent-based post-combustion CO 2 capture (PCC) technology remains one of the leading methods to combat global CO 2 emissions produced from large-scale coal-fired power production. Advanced solventbased PCC technology has made significant improvements in design and performance that reduce capital and operating costs to enable its commercial use. Key to low cost, manageable logistics, and environmentally safe operation of solvent-based PCC technology are minimal solvent losses from the process through the treated gas stream exiting PCC plant absorbers. High flue gas aerosol particle concentrations (>10 5 particles/cm 3 ) for particles in the range of 70-200 nm have been shown to cause significant amine solvent losses for solvent-based PCC processes through several mechanisms including absorption of solvent and water into growing aerosol particles. Flue gas aerosol pretreatment technology is the only realistic and economically attractive method to reduce very high aerosol particle concentrations (>10 7 particles/cm 3 ) to enable solvent-based PCC for existing power plants lacking sufficient particle removal systems, such as baghouses. The overall goal of this project was to design, construct, independently test, and evaluate three flue gas aerosol pretreatment technologies identified to significantly reduce high aerosol particle concentrations (>10 7 particles/cm 3 ) in the 70-200 nm particle size range: (1) a novel, high-velocity water injection spray concept developed by RWE and tested by Linde, (2) an innovative electrostatic precipitator (ESP) device with optimized operating conditions developed by Washington University in St. Louis (WUSTL), and (3) a non-regenerative sorbent-based filter technology developed by InnoSepra for SO x and NO x removal from coal-fired power plant flue gas. Each technology has been validated with tests on 500-1000 scfm of actual coal-fired flue gas and evaluated in terms of particle removal efficiency (%), cost competitiveness, and environmental impact. Aerosol measurements were performed upstream and downstream of each aerosol reduction unit during independent testing of each technology using advanced instrumentation and analytical methods provided by WUSTL. To perform aerosol measurements, isokinetic probes were inserted into flanged pipes attached to the flue gas piping, and a small suction pump was used to sample gas containing aerosol particles. Aerosol particle number concentrations (# particles/cm 3 ) and size distributions were then measured using a scanning mobility particle sizer (SMPS, TSI Inc.) for very fine particles (<1,000 nm) and a particle counter manufactured by GRIMM for particles larger than 1,000 nm. This report summarizes the aerosol removal performance results from pilot scale testing of each technology. Performance results have been benchmarked against pre-defined targets and other flue gas aerosol pretreatment technologies with documented performance. Linde Gas North America LLC has been the prime contractor to DOE responsible for overall project management and provided the design for the high-velocity water spray-based aerosol removal technology based on a design concept developed by the German utility company RWE.

20 FOSSIL-FUELED POWER PLANTS↗

Review of Experimental Decontamination Factors (DF) of Iodine in the Pilot-Scale Law Melter Off-Gas Systems

The Low Activity Waste (LAW) melters at the Hanford Tank Waste Treatment and Immobilization Plant (WTP) will convert low-activity tank wastes containing high concentrations of sodium salts into glass for onsite disposal. Much of the airborne particulates during the calcination/fusion of the feed solids will be removed by condensation and scrubbing of the melter exhaust in the Submerged Bed Scrubber (SBS) and Wet Electrostatic Precipitator (WESP)of the primary off-gas treatment system. The gases exiting the WESP enter a secondary off-gas treatment system, which includes a High-Efficiency Particulate Air (HEPA) filter, an activated carbon absorber, a Thermal Catalytic Oxidizer (TCO), a Selective Catalytic Reduction (SCR) unit, a caustic scrubber, and an exhauster. Much of the volatile organics and NOx will be removed in the TCO and SCR, respectively. Under WTP Direct Feed LAW (DFLAW) configuration, the liquid effluents from the SBS and WESP will be collected and evaporated under vacuum with the evaporator concentrate recycled back to the LAW melter, while the evaporator condensate will be merged with the caustic scrubber solution and sent to the Effluent Treatment Facility (ETF).

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

Estimates of Acetonitrile Generation from Scale Melter Testing of LAW Simulants (VSL-19S4573-1, Rev A)

With high nitrate feeds, such as Hanford low activity waste (LAW) feeds, the addition of reductants is necessary in order to control foaming of the molten glass pool in the melter because such foaming can lead to extensive downtime. Sugar, which was used for this purpose at the West Valley Demonstration Project vitrification facility, has been selected as the baseline reductant for the Hanford Waste Treatment and Immobilization Plant (WTP). The amount of sugar required increases with the amount of nitrates present in the feed and decreases with the amount of waste organics present in the feed, which themselves act as reductants. Excessive additions of reductants can be deleterious, leading to over-reduction of the melt and formation of sulfides and molten metals. Consequently, the oxidants and reductants in the feed must be suitably balanced. The basis for achieving this balance was developed by VSL and Atkins for the vitrification of high-sodium-nitrate feeds at Savannah River's M-Area and has been successfully applied to the processing of a wide variety of simulated WTP feeds over many years and was ultimately incorporated into the WTP process control models. The reaction of sugar with nitrates and nitrites in the cold cap controls the redox state of the underlying melt, which prevents foaming, and also significantly decreases the amount of NOx produced. In addition, however, small amount of organics reaction products are formed. Extensive testing at VSL over the past more than 20 years has shown that acetonitrile is the most prevalent such organic species. That testing has also shown that a significant amount of acetonitrile is captured in the liquid scrubbers in the WTP off-gas treatment system and will therefore be present in the secondary liquid effluents. In particular, acetonitrile is prevalent in the submerged bed scrubber (SBS) and wet electrostatic precipitator (WESP) liquid effluents from WTP LAW off-gas treatment. When these liquids are concentrated in the WTP Effluent Management Facility (EMF) evaporator in the direct feed LAW (DFLAW) flow-sheet, VSL testing has shown that the majority of the acetonitrile partitions to the evaporator condensate. Since the evaporator condensate is directed to the Hanford Effluent Treatment Facility (ETF), this creates a potential issue with the ETF waste acceptance criteria. Consequently, there is a need to assess the available test data in order to develop projections of the likely concentrations of acetonitrile in the streams to ETF. The objective of the present report is to provide such an assessment in order to provide input to flow-sheet model projections.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

Acetonitrile Destruction and Fate of Organics in the Reverse Osmosis System at the ETF

The Hanford Site Effluent Treatment Facility (ETF) currently treats aqueous waste streams that include condensates from the 242-A evaporator, leachate from the Environmental Restoration Disposal Facility (ERDF), as well as laboratory wastes and, in the future, will treat liquid effluents from the Hanford Tank Waste Treatment and Immobilization Plant (WTP) and Integrated Disposal Facility (IDF) leachate. Liquid effluents from the WTP will have significant concentrations of acetonitrile. Acetonitrile is formed by reaction of nitrates and sugar in the WTP low activity waste (LAW) melters and is prevalent in the submerged bed scrubber (SBS) and wet electrostatic precipitator (WESP) liquid effluents from WTP off-gas treatment. When these liquids are concentrated in the WTP Effluent Management Facility (EMF) evaporator in the direct feed low activity waste (DFLAW) flow-sheet, testing has shown that the majority of the acetonitrile partitions to the evaporator condensate. Since the evaporator condensate is directed to the ETF, this creates a potential issue with the ETF waste acceptance criteria. Consequently, there is a need to validate flow-sheet assumptions on the fate of acetonitrile and other organics within the ETF. The present plan includes the addition of a steam stripper to the ETF to remove acetonitrile. There is, therefore, also a need to determine a suitable method to destroy acetonitrile in the overhead condensate stream from the new steam stripper. Washington River Protection Solutions, LLC (WRPS) previously contracted with Atkins and the Vitreous State Laboratory (VSL) of The Catholic University of America (CUA) to perform development and testing work to evaluate potential methods for destruction of acetonitrile in WTP secondary liquid effluents. Based on the results of that work, WRPS requested that follow-on testing be conducted to further evaluate acetonitrile destruction in the steam stripper condensate using ultraviolet oxidation (UV/OX) with persulfate. WRPS also requested testing to assess the rejection rate of organics in the reverse osmosis (RO) system installed in the ETF. This report presents the results from testing to address those needs.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

Coal Feed-Dependent Variation in Fly Ash Chemistry in a Single Pulverized-Combustion Unit

Four suites of fly ash, all generated at the same power plant, were selected for the study of the distribution of rare earth elements (REE). The fly ashes represented two runs of single-seam/single-mine coals and two runs of run-of-mine coals representing several coal seams from several mines. Plots of the upper continental crust-normalized REE, other parameters derived from the normalization, and the principal components analysis of the derived REE parameters (including the sum of the lanthanides plus yttrium and the ratio of the light to heavy REE) all demonstrated that the relatively rare earth-rich Fire Clay coal-derived fly ashes have a different REE distribution, with a greater concentration of REE with a relative dominance of the heavy REE, than the other fly ashes. Particularly with the Fire Clay coal-derived fly ashes, there is a systematic partitioning of the overall amount and distribution of the REE in the passage from the mechanical fly ash collection through to the last row of the electrostatic precipitator hoppers.

58 GEOSCIENCES↗