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www.advancedsciencenews.com www.advancedscience.com 43.0 kWh m−3 (FCDI)[ 28 ] for seawater desalination. Although MCDI and FCDI have been extensively investigated for brack- ish water desalination,[ 29–31 ] the application of these processes to seawater desalination has been limited primarily because their SECs proportionally increase with feed salinity, and the salinity of seawater is often ≈35,000 ppm (total dissolved solids; TDS). For ED, several studies have been reported for seawater desalina- tion, which showed SECs of 6.6 kWh m−3 (99% salt removal),[ 32 ] 15 kWh m−3 (87% salt removal),[ 33 ] 16.2 kWh m−3 (98% salt removal),[ 34 ] or 18.1 kWh m−3 (98% salt removal).[ 35 ] These values are distinctly higher than that of RO (3.5 kWh m−3 for ≈100% salt removal). Note that the SEC of RO varies from 2.5 to 5 kWh m−3 depending on the size of the plant, the number of stages (i.e., single pass), and feed water quality.[36–38] An SEC of 3.5 kWh m−3 was selected as a baseline since this is a common value that often appears in the references.[36–38] The first reported SEC for SWB-D is 53.9 kWh m−3 (≈75% salt removal) in the year 2020,[6] which is similar to MCDI and FCDI. According to literature, the energy consumption of SWB- D is almost proportional to the amount of salt removed.[ 6,8 ] Thus, when 100% of salt removal is assumed, the SEC of SWB-D could proportionally increase to 71.9 kWh m−3, not including the in- crease in salt solution resistance as salt removal reaches 100%. Note that although we ruled out the change of the solution resis- tance during operation to simplify our discussion, the practical SEC can further increase. However, one of the important aspects of SWB-D that can distinguish it from other desalination tech- nologies is its energy storing ability during desalination. In prac- tical application, ≈80% of energy recovery (or energy storing) is often reported for SWB.[ 12 ] This means that 80% of the energy used for charging can be reused for discharging. In this case, the SEC of SWB-D can decrease to 10.8 kWh m−3. When 90% of energy recovery is assumed, which is achievable by reducing the voltage gap during cycling,[12,39] the energy consumption fur- ther decreases to 5.4 kWh m−3. In other literatures, the use of in- tercalating material as a cathode or redox electrolyte solution as catholyte minimized the voltage gap of SWB.[39–41] Thus, similar approaches can be adopted for SWB-D to maximize the energy recovery during desalination. In conclusion, in order for SWB- D to have similar energy consumption and salt removal rate as RO, it must have an energy recovery rate of 95% (3.6 kWh m−3 at 100% salt removal; Open red star in Figure 4) if SWB-D can be operated solely without any pre- and post-treatment of seawater. Since SWB-D system was newly proposed, insufficient infor- mation has been reported regarding the influence of feed wa- ter quality on the overall system performance. However, from the general engineering point of view, similar pre- and post- treatment of seawater could be required for a full-scale op- eration of SWB-D system. This is because untreated seawa- ter contains several organics/inorganic matters and suspended solid/particles, which can easily decrease the overall performance of the system due to channel-clogging and contamination (also known as fouling) of the materials. Thus, for the SWB-D system, additional energy consumption for additional treatment such as intake and pre-treatment of seawater, and distribution of the pro- duced clean water could be further accounted. Note that these are found to be 0.19 kWh m−3 (intake), 0.39 kWh m−3 (pre- treatment), and 0.18 kWh m−3 (distribution) for RO system when the energy consumption was divided by the amount of produced water.[36] To simplify our discussion, however, those additional energy consumptions were not accounted in this study. Another factor that should be considered is the salt removal rate of SWB-D system. Although the maximum salt removal of SWB-D system remains unexplored primarily due to the voltage threshold of the system, the current design of SWB-D system can mostly remove Na+ and Cl− ions. This is because NASICON al- lows only Na+ ions to pass through and AEM has no specific selectivity toward anions. Thus, the maximum salt removal of the current SWB-D system is ≈85%, which is the NaCl portion in seawater.[12] The remaining ions, primarily divalent sulfate (7.6%), magnesium (3.7%), and calcium (1.2%) should be further treated with other methods. In this regard, post-treatment using nanofiltration (NF), which is effective to remove divalent ions, can be considered. Thus, an energy consumption of 0.5 kWh m−3 for NF post-treatment was further added (see the Experimental Section/Methods for details). The result showed that the energy consumption of this system (denotes SWB-D-NF) is competitive to RO when 96% of energy recovery is achieved (3.4 kWh m−3). Thus, the energy recovery ratio of well above 90% should be tar- geted to render SWB-D system competitive to RO in terms of energy consumption. Alternatively, energy-free ion movement, such as diffusion between compartments, particularly between the desalination and cathode compartment, must be considered to reduce the energy used per ion removed. For example, if the ion transportation between the desalination and cathode com- partment is promoted via diffusion, the desalination kinetics can be significantly improved without additional energy consump- tion, thereby lowering the overall SEC used for desalination. Therefore, future studies would need to focus on achieving SECs lower than RO in order for SWB-D to be competitive in the mar- ket of desalination. 2.5. Cost Breakdown of Seawater Battery Desalination and Seawater Battery Similar with other processes, the price of the system dictates the price of the product. To estimate the price of clean water pro- duced, the system price of SWB at a unit cell level was calculated. The energy normalized material cost (unit of $ kWh−1) was cal- culated based on the assessable retail price (Figure 5) although material cost could be significantly reduced by bulk purchasing of chemicals. Thus, the material cost presented in this section aims to provide a simplified number for future reference, not to feature the exact number for the current energy price of SWB based systems. The material cost for two different sizes of SWB (SWBcoin and SWBRect. ) was first calculated. For SWBcoin , the overall ma- terial cost is 150.8 $ kWh−1 in which the separator (NASICON) occupied 122 $ kWh−1 followed by cathodic current collector (cathodic C. C.; 23 $ kWh−1), anode (4 $ kWh−1), and anolyte (2 $ kWh−1). For SWBRect., which has a larger cathodic C.C. than SWBcoin (≈2 cm2 for SWBcoin and ≈68 cm2 for SWBRect.), the overall material cost is 216.4 $ kWh−1. The material cost for the cathodic C. C. (108 $ kWh−1) is dominant for SWBRect. fol- lowed by the separator (86 $ kWh−1), anolyte (18 $ kWh−1), and anode (4 $ kWh−1). The material cost of LIB was reported in the range of ≈88 to ≈200 $ kWh−1 .[ 22,42,43 ] Thus, the material Adv. Sci. 2021, 2101289 2101289 (5 of 9) © 2021 The Authors. Advanced Science published by Wiley-VCH GmbHPDF Image | Seawater Desalination using Rechargeable Seawater Battery
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Product and Development Focus for Salgenx
Redox Flow Battery Technology: With the advent of the new USA tax credits for producing and selling batteries ($35/kW) we are focussing on a simple flow battery using shipping containers as the modular electrolyte storage units with tax credits up to $140,000 per system. Our main focus is on the salt battery. This battery can be used for both thermal and electrical storage applications. We call it the Cogeneration Battery or Cogen Battery. One project is converting salt (brine) based water conditioners to simultaneously produce power. In addition, there are many opportunities to extract Lithium from brine (salt lakes, groundwater, and producer water).Salt water or brine are huge sources for lithium. Most of the worlds lithium is acquired from a brine source. It's even in seawater in a low concentration. Brine is also a byproduct of huge powerplants, which can now use that as an electrolyte and a huge flow battery (which allows storage at the source).We welcome any business and equipment inquiries, as well as licensing our flow battery manufacturing.| CONTACT TEL: 608-238-6001 Email: greg@salgenx.com | RSS | AMP |