scholarly journals Correlations between Properties of Pore-Filling Ion Exchange Membranes and Performance of a Reverse Electrodialysis Stack for High Power Density

Membranes ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 609
Author(s):  
Hanki Kim ◽  
Jiyeon Choi ◽  
Namjo Jeong ◽  
Yeon-Gil Jung ◽  
Haeun Kim ◽  
...  
Keyword(s):  
Ion Exchange ◽  
Power Density ◽  
Electrical Resistance ◽  
Salinity Gradient ◽  
Power Production ◽  
Pilot Scale ◽  
Ion Exchange Membranes ◽  
Pore Filling ◽  
Membrane Area ◽  
Reverse Electrodialysis

The reverse electrodialysis (RED) stack-harnessing salinity gradient power mainly consists of ion exchange membranes (IEMs). Among the various types of IEMs used in RED stacks, pore-filling ion exchange membranes (PIEMs) have been considered promising IEMs to improve the power density of RED stacks. The compositions of PIEMs affect the electrical resistance and permselectivity of PIEMs; however, their effect on the performance of large RED stacks have not yet been considered. In this study, PIEMs of various compositions with respect to the RED stack were adopted to evaluate the performance of the RED stack according to stack size (electrode area: 5 × 5 cm2 vs. 15 × 15 cm2). By increasing the stack size, the gross power per membrane area decreased despite the increase in gross power on a single RED stack. The electrical resistance of the PIEMs was the most important factor for enhancing the power production of the RED stack. Moreover, power production was less sensitive to permselectivities over 90%. By increasing the RED stack size, the contributions of non-ohmic resistances were significantly increased. Thus, we determined that reducing the salinity gradients across PIEMs by ion transport increased the non-ohmic resistance of large RED stacks. These results will aid in designing pilot-scale RED stacks.

scholarly journals Power Generation Performance of a Pilot-Scale Reverse Electrodialysis Using Monovalent Selective Ion-Exchange Membranes

Membranes ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 27
Author(s):  
Soroush Mehdizadeh ◽  
Yuriko Kakihana ◽  
Takakazu Abo ◽  
Qingchun Yuan ◽  
Mitsuru Higa
Keyword(s):  
Power Generation ◽  
Ion Exchange ◽  
Salinity Gradient ◽  
Pilot Scale ◽  
Ion Exchange Membranes ◽  
Okinawa Island ◽  
Membrane Area ◽  
Reverse Electrodialysis ◽  
Desalination Plant ◽  
Power Generation Performance

Reverse electrodialysis (RED) is a promising process for harvesting energy from the salinity gradient between two solutions without environmental impacts. Seawater (SW) and river water (RW) are considered the main RED feed solutions because of their good availability. In Okinawa Island (Japan), SW desalination via the reverse osmosis (RO) can be integrated with the RED process due to the production of a large amount of RO brine (concentrated SW, containing ~1 mol/dm3 of NaCl), which is usually discharged directly into the sea. In this study, a pilot-scale RED stack, with 299 cell pairs and 179.4 m2 of effective membrane area, was installed in the SW desalination plant. For the first time, asymmetric monovalent selective membranes with monovalent selective layer just at the side of the membranes were used as the ion exchange membranes (IEMs) inside the RED stack. Natural and model RO brines, as well as SW, were used as the high-concentrate feed solutions. RW, which was in fact surface water in this study and close to the desalination plant, was utilized as the low-concentrate feed solution. The power generation performance investigated by the current-voltage (I–V) test showed the maximum gross power density of 0.96 and 1.46 W/m2 respectively, when the natural and model RO brine/RW were used. These are a 50–60% improvement of the maximum gross power of 0.62 and 0.97 W/m2 generated from the natural and model SW, respectively. The approximate 50% more power generated from the model feed solutions can be assigned to the suppression of concentration polarization of the RED stack due to the absence of multivalent ions.

scholarly journals High power density of reverse electrodialysis with pore-filling ion exchange membranes and a high-open-area spacer

2015 ◽  
Vol 3 (31) ◽  
pp. 16302-16306 ◽  
Author(s):  
Han-Ki Kim ◽  
Mi-Soon Lee ◽  
Seo-Yoon Lee ◽  
Young-Woo Choi ◽  
Nam-Jo Jeong ◽  
...  
Keyword(s):  
Ion Exchange ◽  
Power Density ◽  
High Power ◽  
High Power Density ◽  
Ion Exchange Membranes ◽  
Open Area ◽  
Pore Filling ◽  
Reverse Electrodialysis

In the present study, a novel reverse electrodialysis (RED) stack with ultrathin lab-made pore-filling membranes and a high-open-area spacer was proposed to enhance the gross power density.

scholarly journals Use of the Microheterogeneous Model to Assess the Applicability of Ion-Exchange Membranes in the Process of Generating Electricity from a Concentration Gradient

Membranes ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 406
Author(s):  
Denis Davydov ◽  
Elena Nosova ◽  
Sergey Loza ◽  
Aslan Achoh ◽  
Alexander Korzhov ◽  
...  
Keyword(s):  
Ion Exchange ◽  
Power Density ◽  
Open Circuit Potential ◽  
Open Circuit ◽  
Transport Numbers ◽  
Ion Exchange Membranes ◽  
Reverse Electrodialysis ◽  
Two Samples ◽  
Microheterogeneous Model ◽  
Experimental Values

The paper shows the possibility of using a microheterogeneous model to estimate the transport numbers of counterions through ion-exchange membranes. It is possible to calculate the open-circuit potential and power density of the reverse electrodialyzer using the data obtained. Eight samples of heterogeneous ion-exchange membranes were studied, two samples for each of the following types of membranes: Ralex CM, Ralex AMH, MK-40, and MA-41. Samples in each pair differed in the year of production and storage conditions. In the work, these samples were named “batch 1” and “batch 2”. According to the microheterogeneous model, to calculate the transport numbers of counterions, it is necessary to use the concentration dependence of the electrical conductivity and diffusion permeability. The electrolyte used was a sodium chloride solution with a concentration range corresponding to the conditional composition of river water and the salinity of the Black Sea. During the research, it was found that samples of Ralex membranes of different batches have similar characteristics over the entire range of investigated concentrations. The calculated values of the transfer numbers for membranes of different batches differ insignificantly: ±0.01 for Ralex AMH in 1 M NaCl. For MK-40 and MA-41 membranes, a significant scatter of characteristics was found, especially in concentrated solutions. As a result, in 1 M NaCl, the transport numbers differ by ±0.05 for MK-40 and ±0.1 for MA-41. The value of the open circuit potential for the Ralex membrane pair showed that the experimental values of the potential are slightly lower than the theoretical ones. At the same time, the maximum calculated power density is higher than the experimental values. The maximum power density achieved in the experiment on reverse electrodialysis was 0.22 W/m2, which is in good agreement with the known literature data for heterogeneous membranes. The discrepancy between the experimental and theoretical data may be the difference in the characteristics of the membranes used in the reverse electrodialysis process from the tested samples and does not consider the shadow effect of the spacer in the channels of the electrodialyzer.

scholarly journals The Effect of Feed Solution Temperature on the Power Output Performance of a Pilot-Scale Reverse Electrodialysis (RED) System with Different Intermediate Distance

Membranes ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 73 ◽  
Author(s):  
Soroush Mehdizadeh ◽  
Masahiro Yasukawa ◽  
Takakazu Abo ◽  
Masaya Kuno ◽  
Yuki Noguchi ◽  
...  
Keyword(s):  
Temperature Dependence ◽  
Power Output ◽  
Salinity Gradient ◽  
Feed Solution ◽  
Pilot Scale ◽  
Solution Temperature ◽  
Natural Seawater ◽  
Experimental Conditions ◽  
Membrane Area ◽  
Reverse Electrodialysis

Membrane-based reverse electrodialysis (RED) can convert the salinity gradient energy between two solutions into electric power without any environmental impact. Regarding the practical application of the RED process using natural seawater and river water, the RED performance depends on the climate (temperature). In this study, we have evaluated the effect of the feed solution temperature on the resulting RED performance using two types of pilot-scale RED stacks consisting of 200 cell pairs having a total effective membrane area of 40 m2 with different intermediate distances (200 µm and 600 µm). The temperature dependence of the resistance of the solution compartment and membrane, open circuit voltage (OCV), maximum gross power output, pumping energy, and subsequent net power output of the system was individually evaluated. Increasing the temperature shows a positive influence on all the factors studied, and interesting linear relationships were obtained in all the cases, which allowed us to provide simple empirical equations to predict the resulting performance. Furthermore, the temperature dependence was strongly affected by the experimental conditions, such as the flow rate and type of stack, especially in the case of the pilot-scale stack.

Patterned ion exchange membranes for improved power production in microbial reverse-electrodialysis cells

2014 ◽  
Vol 271 ◽  
pp. 437-443 ◽  
Author(s):  
Jia Liu ◽  
Geoffrey M. Geise ◽  
Xi Luo ◽  
Huijie Hou ◽  
Fang Zhang ◽  
...  
Keyword(s):  
Ion Exchange ◽  
Power Production ◽  
Ion Exchange Membranes ◽  
Reverse Electrodialysis

scholarly journals Ultra-thin ion exchange film on the ceramic supporter for output power improvement of reverse electrodialysis

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Dong Hyeon Jung ◽  
Eui Don Han ◽  
Byeong Hee Kim ◽  
Young Ho Seo
Keyword(s):  
Ion Exchange ◽  
Electrical Resistance ◽  
Power Source ◽  
Energy Development ◽  
Anion Exchange Membrane ◽  
Ion Exchange Membranes ◽  
Reverse Electrodialysis ◽  
Thin Polymer ◽  
Output Characteristics ◽  
Exchange Membrane

AbstractIn this study, ultra-thin ion exchange film on the ceramic supporter (UTFCS) composed of thin polymer layer and nanoporous ceramic layer with low electrical resistance was developed. The electrical properties and permselectivity of UTFCSs were evaluated and the properties of UTFCSs were compared with other ion exchange membranes. Fabricated UTFCSs were applied to a reverse electrodialysis (RED) system to evaluate the output characteristics and compared with other ion exchange membranes. The power density of RED using UTFCS was 36.6 mW/m2, which was 8% higher than that of a commercial anion exchange membrane. In addition, possibility as power source was experimentally verified by driving LEDs. The proposed UTFCS can be applied not only to RED but also to energy development such as fuel cells and microbial cells.

Harvesting Natural Salinity Gradient Energy for Hydrogen Production Through Reverse Electrodialysis (RED) Power Generation

2016 ◽  
Author(s):  
Mohammadreza Nazemi ◽  
Jiankai Zhang ◽  
Marta Hatzell
Keyword(s):  
Power Density ◽  
Current Density ◽  
Salinity Gradient ◽  
Electrical Energy ◽  
Hydrogen Energy ◽  
External Resistance ◽  
Membrane Area ◽  
Reverse Electrodialysis ◽  
Gradient Energy

There is an enormous potential for energy generation from the mixing of sea and river water at global estuaries. If technologies are developed which are capable of converting this energy into a usable form (electricity or fuels), salinity gradient energy may be able to dramatically increase the worlds supply of renewable energy. Here we present a novel approach to convert this source of energy directly into hydrogen and electricity using Reverse Electrodialysis (RED). RED relies on converting ionic current to electric current using multiple membranes and redox based electrodes. A thermodynamic model for RED is created to evaluate the electricity and hydrogen which can be extracted from natural mixing processes. With equal volumes of HC and LC solutions (0.001m3), the maximum energy extracted is found to occur with 5 number of membrane pairs. At this operating point, 0.4 kWh/m3 can be extracted as electrical energy and 0.95 kWh/m3 of energy is extracted as hydrogen energy. The electrical energy conversion efficiency approaches 15%, whereas the hydrogen energy efficiency is 35%. Overall, the maximum system conversion of Gibbs free energy to electrical and hydrogen energy approaches 50%. The results show that as the number of membrane pairs increases from 5 to 20, the hydrogen power density decreases from 13.2 W/m2 to 3.7 W/m2. Likewise, the power density from electrical energy decreases from 1 W/m2 to 0.3 W/m2. This is because of increase in the total membrane area as increasing the number of membrane pairs. The stack voltage increased from 1.5V to 6V as the number of membrane pairs is increased from 5 to 20. This corresponds to an increase in internal resistance from 600 Ω.cm2 to 2400 Ω.cm2. Long term trade-off between improving the system voltage, while decreasing the system resistance will be crucial for improved long term RED performance. Furthermore, optimum operation of RED, depends on proper selection of external resistance. A small external resistance will increase hydrogen energy and decrease electrical energy, particularly using a small number of membrane pairs. With the fixed small external resistance, as increasing the number of membrane pairs, the difference between internal and external resistance increases. Therefore, the load potential and current density do not increase considerably. For the cases analyzed with 8.29 Ω.cm2 external resistance, the maximum current density increases from 11.1 mA/cm2 to 12.4 mA/cm2 as the number of membrane pairs increases from 5 to 20. Likewise, the load potential rises from 92 mV to 102 mV.

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