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At least 919 records · Page 51

Kinetics and Mechanisms of Calcite Reactions with Saline Waters

Project Description: The general objective of the proposed research is to determine the kinetics and mechanisms of calcite reactions with saline waters over a wide range of saline water composition, pCO 2 , and modest ranges in T and P. This will be accomplished by studying both reaction rates and solubility from changes in solution chemistry, and making nanoscale observations of calcite precipitate surface morphology and composition at the micro-to-nano-scale to provide an understanding of controlling reaction mechanisms and pathways. The specific objectives necessary to reach the general objective are: a) determination of how pCO 2 , Ca 2+ , ionic strength and “foreign” ions influence reaction rates; and b) investigate the influence of these parameters on apparent kinetic solubility from dissolution and precipitation reactions. This information will clearly be central to the construction of reliable reaction-transport models to predict reservoir and formation response to increased CO 2 in saline waters. This program was initially collaborative with John Morse at Texas A&M, however his passing shortly after the beginning of this program resulted in abbreviated research time and effort. Summary of Results: Early studies using electron microscopy and spectroscopy indicated that carbonate precipitation from natural seawater (NSW) conditions onto aragonite substrates was mediated by a surface amorphous calcium carbonate layer. It was hypothesized that this ACC layer (observed after < 5days reaction time) was responsible for the abnormal reaction kinetics and also served as a metastable seed layer for growth of epitaxial aragonite. Further studies of the ACC formation mechanism indicated a strong dependence on the Mg concentration in solution. Subsequent studies at shorter times (10 hrs) on calcite substrates and in a wide range of supersaturation conditions did not indicate any ACC layer. Instead, an epitaxial layer by layer growth mechanism was confirmed by grazing incidence X-ray diffraction, µ-Raman spectroscopy, scanning electron microscopy, transmission electron microscopy, and electron diffraction. Extended time studies out to 45 days confirmed the epitaxial relationship of the overgrowth layer with the substrate. Under NSW conditions, overgrowths were found to have ~0.4 to 0.8 nm / hr growth rates and accommodating 4 at% Mg, resulting in a highly strained overgrowth layer. Following the initial layer by layer growth mechanism, the growth changes to Stranski-Krastanov type after a critical thickness of approximately 100 nm.

58 GEOSCIENCES↗

Development of a Life Cycle Inventory of Water Consumption Associated with the Production of Transportation Fuels

The production of all forms of energy consumes water. To meet increased energy demands, it is essential to quantify the amount of water consumed in the production of different forms of energy. By analyzing the water consumed in different technologies, it is possible to identify areas for improvement in water conservation and reduce water stress in energy-producing regions. The transportation sector is a major consumer of energy in the United States. Because of the relationships between water and energy, the sustainability of transportation is tied to management of water resources. Assessment of water consumption throughout the life cycle of a fuel is necessary to understand its water resource implications. To perform a comparative life cycle assessment of transportation fuels, it is necessary first to develop an inventory of the water consumed in each process in each production supply chain. The Greenhouse Gases, Regulated Emissions, and Energy Use in Transportation (GREET) model is an analytical tool that can used to estimate the full life-cycle environmental impacts of various transportation fuel pathways from wells to wheels. GREET is currently being expanded to include water consumption as a sustainability metric. The purpose of this report was to document data sources and methodologies to estimate water consumption factors (WCF) for the various transportation fuel pathways in GREET. WCFs reflect the quantity of freshwater directly consumed per unit production for various production processes in GREET. These factors do not include consumption of precipitation or low-quality water (e.g., seawater) and reflect only water that is consumed (i.e., not returned to the source from which it was withdrawn). The data in the report can be combined with GREET to compare the life cycle water consumption for different transportation fuels.

energy-water nexus↗

Manufacturing of Protected Lithium Electrodes for Advanced Lithium-Air, Lithium-Water & Lithium-Sulfur Batteries

The global demand for rechargeable batteries is large and growing rapidly. Assuming the adoption of electric vehicles continues to increase, the need for smaller, lighter, and less expensive batteries will become even more pressing. In this vein, PolyPlus Battery Company has developed ultra-light high performance batteries based on its proprietary protected lithium electrode (PLE) technology. The Company’s Lithium-Air and Lithium-Seawater batteries have already demonstrated world record performance (verified by third party testing), and we are developing advanced lithium-sulfur batteries which have the potential deliver high performance at low cost. In this program PolyPlus Battery Company teamed with Corning Incorporated to transition the PLE technology from bench top fabrication using manual tooling to a pre- commercial semi-automated pilot line. At the inception of this program PolyPlus worked with a Tier 1 battery manufacturing engineering firm to design and build the first-of-its-kind pilot line for PLE production. The pilot line was shipped and installed in Berkeley, California several months after the start of the program. PolyPlus spent the next two years working with and optimizing the pilot line and now produces all of its PLEs on this line. The optimization process successfully increased the yield, throughput, and quality of PLEs produced on the pilot line. The Corning team focused on fabrication and scale-up of the ceramic membranes that are key to the PLE technology. PolyPlus next demonstrated that it could take Corning membranes through the pilot line process to produce state-of-the-art protected lithium electrodes. In the latter part of the program the Corning team developed alternative membranes targeted for the large rechargeable battery market. PolyPlus is now in discussions with several potential customers for its advanced PLE-enabled batteries, and is building relationships and infrastructure for the transition into manufacturing. It is likely that the next step will be accomplished through a combination of joint venture partnering and licensing of the technology.

25 ENERGY STORAGE↗

Mapping the Energy-Water Nexus around the Pacific Rim

The energy-water nexus has been mapped for almost 12,000 watersheds distributed across the 21-economies comprising the Asia-Pacific Economic Cooperation. Water consumption for energy production was estimated for 9 different sectors including thermoelectric and hydroelectric power; energy extraction including coal, oil, natural gas, uranium and unconventional oil/gas; and, energy processing including oil and biofuels. Conversely, the energy consumed providing water services was mapped for three sectors, drinking water, waste water and seawater desalination. These measures of resource use were put in context by drawing comparison with published measures of water risk. The objective of the mapping was to quantify the energy-water nexus and its variability at the subnational level, pinpoint potential vulnerabilities, and identify opportunities for international collaboration.

13 HYDRO ENERGY↗

Hydrate Evolution in Response to Ongoing Environmental Shifts

Natural gas hydrates have the potential to become a vital domestic clean-burning energy source. However, past changes in environmental conditions have caused hydrates to become unstable and trigger both massive submarine landslides and the development of crater-like pockmarks, thereby releasing methane into the overlying seawater and atmosphere, where it acts as a powerful greenhouse gas. This project was designed to fill critical gaps in our understanding of domestic hydrate resources and improve forecasts for their response to environmental shifts. Project work can be separated into three interrelated components, each involving the development of predictive mathematical models. The first project component concerns the role of sediment properties on the development and dissociation of concentrated hydrate anomalies. To this end, we developed numerical models to predict equilibrium solubility of methane in twophase equilibrium with hydrate as a function of measureable porous medium characteristics. The second project component concerned the evolution of hydrate distribution in heterogeneous reservoirs. To this end, we developed numerical models to predict the growth and decay of anomalies in representative physical environments. The third project component concerned the stability of hydrate-bearing slopes under changing environmental conditions. To this end, we developed numerical treatments of pore pressure evolution and consolidation, then used "infinite-slope" analysis to approximate the landslide potential in representative physical environments, and developed a "rate-and-state" frictional formulation to assess the stability of finite slip patches that are hypothesized to develop in response to the dissociation of hydrate anomalies. The increased predictive capabilities that result from this work provide a framework for interpreting field observations of hydrate anomalies in terms of the history of environmental forcing that led to their development. Moreover, by taking explicit account of anomaly dissociation, project results are designed to help improve forecasts for changes in slope stability that could pose significant threats to energy infrastructure, disrupt hydrate reserves, and pollute the atmosphere with vast quantities of methane. This report presents the details of our work and outlines some of the highlights from our findings.

03 NATURAL GAS↗

Development of Ultrafiltration Membrane-Separation Technology for Energy-Efficient Water Treatment and Desalination Process

The growing scarcity of fresh water is a major political and economic challenge in the 21st century. Compared to thermal-based distillation technique of water production, pressure driven membrane-based water purification process, such as ultrafiltration (UF), nanofiltration (NF) and reverse osmosis (RO), can offer more energy-efficient and environmentally friendly solution to clean water production. Potential applications also include removal of hazardous chemicals (i.e., arsenic, pesticides, organics) from water. Although those membrane-separation technologies have been used to produce drinking water from seawater (desalination) and non-traditional water (i.e., municipal wastewater and brackish groundwater) over the last decades, they still have problems in order to be applied in large-scale operations. Currently, a major huddle of membrane-based water purification technology for large-scale commercialization is membrane fouling and its resulting increases in pressure and energy cost of filtration process. Membrane cleaning methods, which can restore the membrane properties to some degree, usually cause irreversible damage to the membranes. Considering that electricity for creating of pressure constitutes a majority of cost (~50%) in membrane-based water purification process, the development of new nano-porous membranes that are more resistant to degradation and less subject to fouling is highly desired. Styrene-ethylene/butylene-styrene (SEBS) block copolymer is one of the best known block copolymers that induces well defined morphologies. Due to the polarity difference of aromatic styrene unit and saturated ethylene/butylene unit, these two polymer chains self-assemble each other and form different phase-separated morphologies depending on the ratios of two polymer chain lengths. Because the surface of SEBS is hydrophobic which easily causes fouling of membrane, incorporation of ionic group (e,g, sulfonate) to the polymer is necessary to reduces fouling. Recently, sulfonated SEBS became commercially available and has been extensively explored for membrane-mediated water purification technology. The sulfonated block copolymer creates a well developed nano-sale phase-separated morphologies composed of hydrophilic domains (sulfonated polystyrene) and hydrophobic domains (polyethylene/polybutylene). The hydrophilic domains determines transport properties (water transport, salt and/or ion rejection, etc) and the hydrophobic domains provides mechanical stability of the membrane. Unfortunately, a high degree of sulfonation of SEBS induces excessive swelling and deterioration of mechanical stability of the membrane. In an effort to develop robust polymeric membrane materials for water purification technology, phosphonic acid-functionalized SEBS membranes are investigated during this report period. In compare to sulfonated polymers, the corresponding phosphonated polymers are known to swell less because of the formation of extensive hydrogen bonding networks between phosphonates. In addition to the expected better mechanical stability, phosphonated polymers has another advantage over sulfonated polymers for the use water purification membrane; each phosphonate can accommodate two ions while each sulfonate accommodates only one ion. Membrane properties (ion type, ionic density, etc) of new membranes will be studied and their separation performance will be evaluated in water purification and desalination process. Through systematic study of the relationship of chemical structure–surface property–membrane performance, we aim to better understand the nature of membrane fouling and develop more fouling-resistant water purification membranes. The basic understanding of this relationship will lead to the development of advanced membrane materials which can offer a solution to environmentally sustainable production of fresh water.

36 MATERIALS SCIENCE↗

Advancing Commercialization of Algal Biofuel through Increased Biomass Productivity and Technical Integration

The proposed project built on the foundation of over several years years of intensive and ground-breaking R&D work at Cellana's Kona Demonstration Facility (KDF). Phycological and engineering solutions were provided to tackle key cultivation issues and technical barriers limiting algal biomass productivity identified through work conducted outdoors at industrial (1 acre) scale. The objectives of this project were to significantly improve algal biomass productivity and reduce operational cost in a seawater-based system, using results obtained from two top-performing algal strains as the baseline while technically advancing and more importantly, integrating the various unit operations involved in algal biomass production, processing, and refining.

09 BIOMASS FUELS↗

Volume 1: Survey of Available Information in Support of the Energy-Water Bandwidth Study of Desalination Systems

The U.S. Department of Energy (DOE) has set a goal to reduce the cost of seawater desalination systems to $0.50/ cubic meter (m 3 ) through the development of technology pathways to reduce energy, capital, operating, soft, and system integration costs.1 In support of this goal and to evaluate the technology pathways to lower the energy and carbon intensity of desalination while also reducing the total water cost, DOE is undertaking a comprehensive study of the energy consumption and carbon dioxide (CO 2 ) emissions for desalination technologies and systems. This study is being undertaken in two phases. Phase 1, Survey of Available Information in Support of the Energy-Water Bandwidth Study of Desalination Systems, collected the background information that will underpin Phase 2, the Energy Water Bandwidth Study for Desalination Systems. This report (Volume 1) summarizes the results from Phase 1. The results from Phase 2 will be summarized in Volume 2: Energy Water Bandwidth Study for Desalination Systems (Volume 2). The analysis effort for Phase 2 will utilize similar methods as other industry-specific Energy Bandwidth Studies developed by DOE,2 which has provided a framework to evaluate and compare energy savings potentials within and across manufacturing sectors at the macroscale. Volume 2 will assess the current state of desalination energy intensity and reduction potential through the use of advanced and emerging technologies. For the purpose of both phases of study, energy intensity is defined as the amount of energy required per unit of product water output (for example, kilowatt-hours per cubic meter of water produced). These studies will expand the scope of previous sectorial bandwidth studies by also evaluating CO 2 intensity and reduction opportunities and informing a techno-economic analysis of desalination systems. Volume 2 is expected to be completed in 2017.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

Next-Generation Factory-Produced Cool Asphalt Shingles: Phase 1 Final Report

As the least expensive category of high-slope roofing in the U.S., shingles are found on the roofs of about 80% of U.S. homes, and constitute about 80% (by product area) of this market. Shingles are also among the least reflective high-slope roofing products, with few cool options on the market. The widespread use of cool roofs in the two warmest U.S. climate zones could reduce annual residential cooling energy use in these zones by over 7%. This project targets the development of high-performance cool shingles with initial solar reflectance at least 0.40 and a cost premium not exceeding US$0.50/ft². Phase 1 of the current study explored three approaches to increasing shingle reflectance. Method A replaces dark bare granules by white bare granules to enhance the near-infrared reflectance attained with cool pigments. Method B applies a white basecoat and a cool-color topcoat to a shingle surfaced with dark bare granules. Method C applies a visually clear, NIR-reflecting surface treatment to a conventionally colored shingle. Method A was the most successful, but our investigation of Method B identified roller coating as a promising top-coating technique, and our study of Method C developed a novel approach based on a nanowire mesh. Method A yielded red, green, brown, and black faux shingles with solar reflectance up to 0.39 with volumetric coloration. Since the base material is white, these reflectances can readily be increased by using less pigment. The expected cost premium for Method A shingles is less than our target limit of $0.50/ft², and would represent less than a 10% increase in the installed cost of a shingle roof. Using inexpensive but cool (spectrally selective) iron oxide pigments to volumetrically color white limestone synthesized from sequestered carbon and seawater appears to offer high albedo at low cost. In Phase 2, we plan to refine the cool shingle prototypes, manufacture cool granules, and manufacture and market high-performance cool shingles.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

Selectivity in Ligand Binding to Uranyl Compounds: A Synthetic, Structural, Thermodynamic and Computational Study

The uranyl cation (UO 2 2+ ) is the most abundant form of uranium on the planet. It is estimated that 4.5 billion tons of uranium in this form exist in sea water. The ability to bind and extract the uranyl cation from aqueous solution while separating it from other elements would provide a limitless source of nuclear fuel. A large body of research concerns the selective recognition and extraction of uranyl. A stable molecule, the cation has a linear O=U=O geometry. The short U-O bonds (1.78 Å) arise from the combination of uranium 5f/6d and oxygen 2p orbitals. Due to the oxygen moieties being multiply bonded, these sites were not thought to be basic enough for Lewis acidic coordination to be a viable approach to sequestration. We believe that the goal of developing a practical system for uranium separation from seawater will not be attained without new insights into our existing fundamental knowledge of actinide chemistry. We posit that detailed studies of the kinetic and thermodynamic factors that influence interactions between f-elements and ligands with a range of donor atoms is essential to any major advance in this important area. The goal of this research is thus to broaden the coordination chemistry of the uranyl ion by studying new ligand systems via synthetic, structural, thermodynamic and computational methods. We anticipate that this fundamental science will find use beyond actinide separation technologies in areas such as nuclear waste remediation and nuclear materials.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Analyzing Solutions High in Total Dissolved Solids for Rare Earth Elements (REEs) Using Cation Exchange and Online Pre-Concentration with the seaFAST2 Unit; NETL-TRS-7-2017; NETL Technical Report Series; U.S. Department of Energy, National Energy Technology Laboratory: Albany, OR, 2017; p 32

The accurate quantification of the rare earth element (REE) dissolved concentrations in natural waters are often inhibited by their low abundances in relation to other dissolved constituents such as alkali, alkaline earth elements, and dissolved solids. The high abundance of these constituents can suppress the overall analytical signal as well as create isobaric interferences on the REEs during analysis. Waters associated with natural gas operations on black shale plays are characterized by high salinities and high total dissolved solids (TDS) contents >150,000 mg/L. Methods used to isolate and quantify dissolved REEs in seawater were adapted in order to develop the capability of analyzing REEs in waters that are high in TDS. First, a synthetic fluid based on geochemical modelling of natural brine formation fluids was created within the Marcellus black shale with a TDS loading of 153,000 mg/L. To this solution, 1,000 ng/mL of REE standards was added based on preliminary analyses of experimental fluids reacted at high pressure and temperature with Marcellus black shale. These synthetic fluids were then run at three different dilution levels of 10, 100, and 1,000–fold dilutions through cation exchange columns using AG50-X8 exchange resin from Eichrom Industries. The eluent from the cation columns were then sent through a seaFAST2 unit directly connected to an inductively coupled plasma mass spectrometer (ICP-MS) to analyze the REEs. Percent recoveries of the REEs ranged from 80–110% and fell within error for the external reference standard used and no signal suppression or isobaric interferences on the REEs were observed. These results demonstrate that a combined use of cation exchange columns and seaFAST2 instrumentation are effective in accurately quantifying the dissolved REEs in fluids that are >150,000 mg/L in TDS and have Ba:Eu ratios in excess of 380,000.

03 NATURAL GAS↗

Fouling-Resistant Membranes for Treating Concentrated Brines for Water Reuse in Advanced Energy Systems- Final Technical Report

The high total dissolved solids (TDS) levels in the wastewater quality generated from unconventional oil and gas development make the current state-of-the art approach to water treatment/disposal untenable. Our proposed membrane technology approach addresses the two major challenges associated with this water: 1) the membrane distillation process removes the high TDS content, which is often 8 times higher than that of seawater, and 2) our novel membrane coating prevents the formation of scale that would otherwise pose a significant operational hurdle. This is accomplished through next-generation electrically conductive membranes that mitigate fouling beyond what is currently possible, and allow for the flexibility to treat to the water to levels desirable for multiple reuse options, thus reducing fresh water withdrawal, all the way to direct disposal into the environment. The overall project objective was to demonstrate the efficacy of membrane distillation (MD) as a cost-savings technology to treat concentrated brines (such as, but not limited to, produced waters generated from fossil fuel extraction) that have high levels of TDS for beneficial water reuse in power production and other industrial operations as well as agricultural and municipal water uses. In addition, a novel fouling-resistant nanocomposite membrane was developed to reduce the need for chemicals to address membrane scaling due to the precipitation of divalent ions in high-TDS waters and improve overall MD performance via an electrically conductive membrane distillation process (ECMD). This anti-fouling membrane technology platform is based on incorporating carbon nanotubes (CNTs) into the surface layer of existing, commercially available MD membranes. The CNTs impart electrical conductivity to the membrane surface to prevent membrane scaling and fouling when an electrical potential is applied.

36 MATERIALS SCIENCE↗

Analysis of SNL/MSU/DOE Fatigue Database Trends for Wind Turbine Blade Materials 2010-2015.

Wind turbine blades are designed to several major structural conditions, including tip deflection, strength and b uckling during severe loading, as well as very high numbers of fatigue cycles and various service environments. The MSU Database Program has, since 1989, addressed the broad range of properties needed for current and potential blade materials through stati c and fatigue testing and test development in cooperation with Sandia National Laboratories and wind industry and supplier partners. This report is the latest in a series, giving test results and analysis for the period 2010 - 2015. Program data are compiled in a public database [1] and other reports and publications given in the cited references. The report begins with an executive summary and introductory material including background discussion of previous related studies. Section 3 describes experimental methods including processing, test methods, instrumentation and test development. Section 4 provides static tension, compression and shear stress - strain properties in three directions using coupons sectioned from a thick infused unidirectional glass/epoxy laminate. The nonlinear, shear dominated static properties were characterized with loading - u nloading - reloading (LUR) tests in tension and compression to increasing load levels, for +-45O laminates. Section 5 explores the origins of tensile fatigue sensitivity in glass fiber dominated laminates with variations in fabric architecture including speci ally prepared fabrics and aligned strand laminates. Several types of resins are considered, with variations in resin toughness and bonding to fibers, as well as cure cycle variations for an epoxy. Conclusions are drawn as to the limits of tensile fatigue r esistance and the effects of resin type and fabric architecture, including the behavior of a commercial aligned glass strand product. Interactions between cyclic fatigue response and creep are addressed for off - axis (+-45O) glass/epoxy laminates in Sectio n 6. The nonlinear fatigue and creep stress - strain and cumulative strain response are characterized in tension and compression as a function of stress level, cycles and cumulative time, using square and sinewave loading over a broad range of frequency. The results are analyzed in terms of the cycles and cumulative time under load. A cumulative strain failure criterion is established, and used to construct shear and tension constant life diagrams (CLD's) with data for nine R - values. The effects of a more duc tile urethne resin are also explored. A previous study of thick adhesives testing is extended to mixed mode fracture mechanics testing in Section 7. Mechanisms of static and fatigue crack extension near the laminate adherend interface are reported in deta il. Data are presented for mixed mode adhesive fracture, compared to mixed mode fracture in ply delamination. Fatigue crack growth exponents are also developed for a mixed mode cracked lap shear coupon. The data for fatigue trends and relative failure stra ins and exponents are compared for various blade component materials in Section 8. The effects of temperature and seawater saturation are considered for selected materials of interest for wind and hydrokinetic turbine blades in Section 9. Section 10 gives detailed conclusions for each section. A cknowledgements The research presented in this report was carried out under Sandia National Laboratories purchase orders 1325028 an d 1543945 between 2010 and 2015, with support from the DOE Wind and Water Technologies Office . In addition to the authors listed, significant contributions were made by Patrick Flaherty, Pancastya Agastra, Michael Schuster, and Michael Voth. Industry m aterials suppliers include Vectorply, Saertex, OCV, AGY, Bayer, Ashland, 3M and Nextel. Industry suppliers with significant contributions to the study were Hexion, PPG, Reichhold, Gurit and NEPTCO. Intentionally Left Blank

17 WIND ENERGY↗

TDAAPS 2: Acoustic Wave Propagation in Attenuative Moving Media

This report outlines recent enhancements to the TDAAPS algorithm first described by Symons et al., 2005. One of the primary additions to the code is the ability to specify an attenuative media using standard linear fluid mechanisms to match reasonably general frequency versus loss curves, including common frequency versus loss curves for the atmosphere and seawater. Other improvements that will be described are the addition of improved numerical boundary conditions via various forms of Perfectly Matched Layers, enhanced accuracy near high contrast media interfaces, and improved physics options.

47 OTHER INSTRUMENTATION↗

Survey Study of Trunk Materials for Direct ATRP Grafting

In previous study, we demonstrated a new method to prepare polymeric fiber adsorbents via a chemical-grafting method, namely atom-transfer radical polymerization (ATRP), and identified parameters affecting their uranium adsorption capacity. However, ATRP chemical grafting in the previous study still utilized conventional radiation-induced graft polymerization (RIGP) to introduce initiation sites on fibers. Therefore, the objective of the present study is to perform survey study of trunk fiber materials for direct ATRP chemical grafting method without RIGP for the preparation of fiber adsorbents for uranium recovery from seawater.

36 MATERIALS SCIENCE↗

High Ion-Accessible Surface Area CNT-Ultracapacitors for Groundwater Desalination

Fresh water is a vital resource for human survival, as well as a key component for a wide range of industrial and agricultural needs. However, only 0.65% of the world’s water resources are available as fresh water, and the demand on the world’s water reserves continues to rise, with the demand already beginning to outpace the supply in many areas. A water-energy nexus is being reached that requires low -cost and -energy solutions for various degrees of treated water. Public awareness of the problem has also risen, such that in a 2012 survey, 88% of Americans reported concerns about potential water shortages. Approximately two-thirds of the world’s population could suffer water shortages over the next few years. Seawater and other saline water supplies make up around 98% of the world’s accessible water. Properly treated to reduce the levels of salinity, this represents an almost unlimited supply of fresh water. The high energy requirements, capital costs, and maintenance requirements to remove salts and other unwanted compounds, however, are barriers to widespread implementation of salt-to-freshwater facilities. These facilities most commonly use reverse osmosis (RO) systems that suffer from high required pressures and failures of moving parts; additionally, these facilities consume much grid energy and require constant maintenance, leading to high capital and operational costs. The RO process also generates large volumes of highly concentrated bio-hazardous brine that is costly to safely return to the ocean. In contrast to RO, capacitive desalination or capacitive deionization (CDI) has fewer moving parts (a low-pressure pump and several valves), operates at low pressure, and does not generate large quantities of brine that are hazardous to marine life. The capacitive charge/discharge of a CDI system can be cycled almost indefinitely, and the system has low energy requirements because the capacitive discharge electrical current can be co-generated back to the system. RO must remove the water from the salt while CDI removes the salt from the water. This represents a significant difference in the number of molecules which must be moved and energy required to desalinate water. However, CDI has not seen widespread use for large- or small-scale desalination because electrode efficiency has limited the extraction rate below what is useful for most applications. Mainstream demonstrated the following successes during this SBIR program: Performance - We developed an innovative new electrode structure for the high-efficiency removal of ions from salt-contaminated water samples by CDI. Based on prototype electrochemical tests, our CDI consumes as low as 0.71 kW/m 3 of treated water (compared to 2.9 to 3.7 kW/m 3 for RO). Scalability – During Phase II, we increased the electrode size from 3.8 cm 2 single-sided electrodes to 180 cm 2 double-sided electrodes. Using larger acid baths and CVD furnace, we increased electrode fabrication capacity increased by 315 times. Scalable electrochemical CDI stack design and balance of plant – During Phase II, we demonstrated at scalable low-pressure drop stack design and balance of plant for the continuous removal of ions. Corrosion Resistance – Based on accelerated corrosion testing data, our high-quality graphitic electrodes have a significantly improved corrosion resistance. This was 20 times better corrosion resistance than our Phase I electrodes and significantly higher than typical CDI system electrodes. Flexibility –By tuning the pore size of the electrode materials, we demonstrated the removal of key target ionic contaminants, such as sodium chloride, nitrate, and phosphate salts. These ionic contaminants are common in agricultural and industrial wastewater runoff and are difficult to remove by conventional methods, which require excessive use of reagents.

Cox, Dr. Philip↗

Integration of High Temperature Gas-Cooled Reactors into Selected Industrial Process Applications

This report summarizes the material and energy requirements and preliminary economics for conventional and high temperature gas-cooled reactor -integrated processes that recover oil from oil shale, desalinate seawater, and upgrade bitumen to synthetic crude oil. Also included are summaries of other industrial processes that were briefly evaluated, which included processes to produce metallurgical coke and steel. The appendices include more detailed technical analyses for each of the processes. This report updates a prior similar report (INL 2010) by summarizing the additional work accomplished in FY 2011.

42 ENGINEERING↗

Integrated pre-feasibility study for CO 2 geological storage in the Cascadia Basin, offshore Washington State, British Columbia

The Cascadia CarbonSAFE project conducted a pre-feasibility study to evaluate technical and nontechnical aspects of storing 50 million metric tons (MMT) of carbon dioxide in a safe, ocean basalt reservoir offshore Washington State and British Columbia. Sub-seafloor basalts are very common on Earth and enable geological mineralization as a long-term storage mechanism, permanently sequestering the carbon in solid rock form. This project evaluated the offshore storage complex, developed potential industrial source/transport scenarios, built an inventory of existing geophysical/geological data and environmental monitoring capabilities, conducted laboratory studies and reservoir modeling to determine storage capacity, and analyzed economic factors, regulatory requirements, and project management risks. Our team included researchers at Columbia University in New York, Pacific Northwest National Laboratory (PNNL) in Washington, University of Victoria in British Columbia, University of California at Santa Cruz, and GHG Underground in Maine, as well as collaborators at University of Iceland in Reykjavik and University of Washington in Saint Louis. In the study region, large emitters (>100,000 MT/year) generate a total of approximately 40 MMT annually from stationary sources, such as power plants, refineries, ammonia production, and mineral processing plants. Five potential industry source/transport scenarios were identified (three in U.SA S. and two in Canada) to potentially provide 50 MMT of carbon dioxide to the offshore reservoir. One scenario included net carbon-negative sources that would reduce atmospheric levels. The inventory of existing data illustrated that basalt properties in the region are potentially beneficial for long-term storage. Permeability is on the order of 0.1 to 1 Darcies within the uppermost 600 m of ocean crust and density-derived porosity reaches 10–20% in thin layers that provide act as flow channels and provide access to porous and permeable basalt. Fine-grained sediments overlying basalt provide a low-permeability barrier separating the storage reservoir from the overlying ocean. Subsurface monitoring of the storage complex benefits from a unique opportunity close proximity of to the nearby NEPTUNE cabled seafloor observatory, which actively transmits data to shore and could be used to monitor reservoir properties. Injection pressure changes, reservoir chemistry, seismicity, well head corrosion, and potential leakage monitoring would be feasible in real time. Using existing data and published models, the STOMP-CO 2 modeling code developed at PNNL was used to simulate carbon dioxide injection, storage, and mineralization in the reservoir. Preliminary simulations indicate that a 50 MMT carbon dioxide plume injected over a 20-year period remains well within the reservoir area, both laterally and vertically, for at least a 50-year period of post-injection monitoring. Laboratory studies on core samples from Cascadia measured dissolution rates in CO 2 –basalt–seawater mixtures and indicated large variability in rates with the potential for complete mineralization. Compared to published data, the dissolution rate measured in these samples is faster, decreasing the time until full conversion to carbonate minerals would occur. Adding geochemical reactivity in the STOMP-CO 2 model indicates that carbon dioxide would be fully converted to carbonate minerals in 135 years or less after injection ceases. The project assessed the viability and costs for the five scenarios using either dedicated offshore pipelines or shipping vessels. Carbon dioxide capture costs were not considered. Shipping incurred lower upfront CAPEX costs, and because most viable sources were located near the shore and waterways, shipping is preferred; no dedicated carbon dioxide pipelines exist in the region. The project also considered potential risks from mixed-use impacts on surrounding lands and ocean areas, such as active use by commercial and recreational fisherman, and other community considerations in planning for public engagement in the future. Other project risks were identified, including project management, permitting and compliance, and financing, as well as technical issues such as long-term instrumentation, plume migration, and model development. Geological concerns like reservoir permeability, seal, and induced seismicity held relatively low risk. The regulatory framework for offshore storage in the U.S. and Canada may be covered by general legal/regulatory programs, but is not yet fully defined. Existing programs appear to restrict the transportation of carbon dioxide across national boundaries (e.g., Canada to U.S.) and its sub-seabed disposal in some circumstances. Our assessment suggests that developing specific and separate pilot projects will help to advance the technical feasibility and regulatory requirements in each country, and lessons learned from such activities may be transferable elsewhere around the globe.

42 ENGINEERING↗