High performance asymmetric capacitive mixing with oppositely charged carbon electrodes for energy production from salinity differences

2017 ◽  
Vol 5 (38) ◽  
pp. 20374-20380 ◽  
Author(s):  
Fei Zhan ◽  
Gang Wang ◽  
Tingting Wu ◽  
Qiang Dong ◽  
Yulan Meng ◽  
...  
Keyword(s):  
Power Density ◽  
Energy Production ◽  
High Performance ◽  
Salinity Gradient ◽  
Average Power ◽  
Carbon Electrodes ◽  
Voltage Rise ◽  
Gradient Energy ◽  
Oppositely Charged

Asymmetric capacitive mixing (Asy-CapMix) for extracting salinity gradient energy is realized by using oppositely charged carbon electrodes. High performance in terms of voltage rise and average power density is achieved.

Determining the Potential of Salinity Gradient Energy Source Using an Exergy Analysis

2016 ◽  
Author(s):  
Arash Emdadi ◽  
Mansour Zenouzi ◽  
Gregory J. Kowalski
Keyword(s):  
Sodium Chloride ◽  
Power Density ◽  
Chloride Solution ◽  
Sodium Chloride Solution ◽  
Exergy Analysis ◽  
Salinity Gradient ◽  
Chloride Concentration ◽  
Semipermeable Membranes ◽  
Dead State ◽  
Gradient Energy

Mixing of fresh (river) water and salty water (seawater or saline brine) in a control fashion would produces an electrical energy known as salinity gradient energy (SGE). Two main conversion technologies of SGE are membrane-based processes; pressure retarded osmosis (PRO) and reverse electrodialysis (RED). In PRO, semipermeable membranes placed between the two streams of solutions allow the transport of water from low-pressure diluted solution to high-pressure concentrated solution. RED requires two alternating semipermeable membranes that allow the diffusion of the ions but not the flow of H2O. Lifetime and power density of the semipermeable membrane are two main factors affecting on deployment of PRO and RED. Semipermeable membranes with lifetime greater than 10 years and power density higher than 5 W/m2 would lead to faster development of this conversion technology. An exergy analysis of an SGE system of sea-river can be applied to calculate the maximum potential power for electricity generation. Seawater is taken as reference environment (global dead state) for calculating the exergy of water since the seawater is the final reservoir. Once the fresh water is mixed with water of the sea or lake it becomes unuseful for human, agricultural or industrial uses loses all its exergy. Aqueous sodium chloride solution model is used in this study to calculate the thermodynamic properties of seawater. This model does not consider seawater as an ideal model and provides accurate thermodynamics properties of sodium chloride solution. As a case study, exergy calculation of Iran’s Urmia Lake-GadarChay River system. The chemical exergy analysis considers sodium chloride (NaCl) as main salt in the water of Lake Urmia. The sodium chloride concentration is more than 200 g/L in recent years. Based on the exergy results the potential power of this system is 329 MW. This results indicates a high potential for constructing power plant for salinity gradient energy conversion.

scholarly journals Feasibility of Pressure-Retarded Osmosis for Electricity Generation at Low Temperatures

Membranes ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 556
Author(s):  
Elham Abbasi-Garravand ◽  
Catherine N. Mulligan
Keyword(s):  
Power Density ◽  
Membrane Fouling ◽  
Low Temperatures ◽  
Sea Water ◽  
Salinity Gradient ◽  
Operating Conditions ◽  
Pressure Retarded Osmosis ◽  
Water Transportation ◽  
Gradient Energy ◽  
Temperature Impact

A membrane-based technique for production of pressure-retarded osmosis (PRO) is salinity gradient energy. This sustainable energy is formed by combining salt and fresh waters. The membrane of the PRO process has a significant effect on controlling the salinity gradient energy or osmotic energy generation. Membrane fouling and operating conditions such as temperature have an extreme influence on the efficiency of the PRO processes because of their roles in salt and water transportation through the PRO membranes. In this study, the temperature impact on the power density and the fouling of two industrial semi-permeable membranes in the PRO system was investigated using river and synthetic sea water. Based on the findings, the power densities were 17.1 and 14.2 W/m2 at 5 °C for flat sheet and hollow fiber membranes, respectively. This is the first time that research indicates that power density at low temperature is feasible for generating electricity using PRO processes. These results can be promising for regions with high PRO potential that experience low temperatures most of the year.

Bioinspired fractal nanochannels for high-performance salinity gradient energy conversion

2019 ◽  
Vol 418 ◽  
pp. 33-41 ◽  
Author(s):  
Zhengfei Kuang ◽  
Dijing Zhang ◽  
Yuemin Shen ◽  
Rui Long ◽  
Zhichun Liu ◽  
...  
Keyword(s):  
Energy Conversion ◽  
High Performance ◽  
Salinity Gradient ◽  
Gradient Energy

scholarly journals Modeling and Optimization of Membrane Process for Salinity Gradient Energy Production

Separations ◽  
2021 ◽  
Vol 8 (5) ◽  
pp. 64
Author(s):  
Lianfa Song
Keyword(s):  
Osmotic Pressure ◽  
Energy Production ◽  
Salinity Gradient ◽  
Water Flux ◽  
Hydraulic Pressure ◽  
Semipermeable Membranes ◽  
Pressure Retarded Osmosis ◽  
Higher Power ◽  
Gradient Energy ◽  
Breakeven Point

When hydraulic pressure was added on the feed side of the membrane in the otherwise conventional pressure retarded osmosis (PRO) process, the production rate of the salinity gradient energy could be significantly increased by manipulating the hydraulic pressures on both sides of the membrane. With hydraulic pressure added on the feed side of the membrane, much higher water flux could be obtained than that under the osmotic pressure of the same value. The osmotic pressure of the draw solution, instead of drawing water through the membrane, was mainly reserved to increase the hydraulic pressure of the permeate. In this way, orders of magnitude higher power density than that in the conventional PRO can be obtained with the same salinity gradient. At the optimal conditions, it was demonstrated that the energy production rates that were much higher than the economical breakeven point could be obtained from the pair of seawater and freshwater with the currently available semipermeable membranes.

High performance concentration capacitors with graphene hydrogel electrodes for harvesting salinity gradient energy

2018 ◽  
Vol 6 (12) ◽  
pp. 4981-4987 ◽  
Author(s):  
Fei Zhan ◽  
Zijian Wang ◽  
Tingting Wu ◽  
Qiang Dong ◽  
Changtai Zhao ◽  
...  
Keyword(s):  
High Performance ◽  
Salinity Gradient ◽  
P Concentration ◽  
Gradient Energy

Concentration capacitors with graphene hydrogel electrodes are proposed to efficiently harvest salinity gradient energy.

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.

Membrane research for salinity gradient energy production. Final report

1978 ◽  
Author(s):  
H. K. Lonsdale ◽  
R. W. Baker ◽  
K. L. Lee ◽  
K. L. Smith
Keyword(s):  
Energy Production ◽  
Salinity Gradient ◽  
Final Report ◽  
Gradient Energy
Sign in / Sign up

Export Citation Format

Share Document