Sustainable hydrogen production from seawater and sewage treated water using reverse electrodialysis technology

2019 ◽  
Vol 14 (3) ◽  
pp. 645-651 ◽  
Author(s):  
Mitsuru Higa ◽  
Takeshi Watanabe ◽  
Masahiro Yasukawa ◽  
Nobutaka Endo ◽  
Yuriko Kakihana ◽  
...  
Keyword(s):  
Hydrogen Production ◽  
Production System ◽  
Salinity Gradient ◽  
Water Electrolysis ◽  
Direct Conversion ◽  
Pilot Scale ◽  
Hydrogen Energy ◽  
Treated Water ◽  
Reverse Electrodialysis ◽  
Gradient Energy

Abstract A pilot-scale sustainable hydrogen production system using reverse electrodialysis (RED) technology was launched. The system is based on direct conversion of salinity gradient energy (SGE) between seawater (SW) and sewage treated water (STW) to hydrogen production by water electrolysis. The hydrogen production rate was almost the same as the theoretical value. This indicates that the RED hydrogen production system can convert SGE between SW and STW to hydrogen energy at high current efficiency.

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.

Reverse electrodialysis in bilayer nanochannels: salinity gradient-driven power generation

2018 ◽  
Vol 20 (10) ◽  
pp. 7295-7302 ◽  
Author(s):  
Rui Long ◽  
Zhengfei Kuang ◽  
Zhichun Liu ◽  
Wei Liu
Keyword(s):  
Power Generation ◽  
Energy Harvesting ◽  
Salinity Gradient ◽  
Reverse Electrodialysis ◽  
Gradient Energy ◽  
Ion Transportation

To evaluate the possibility of nano-fluidic reverse electrodialysis (RED) for salinity gradient energy harvesting, we consider the behavior of ion transportation in a bilayer cylindrical nanochannel with different sized nanopores connecting two reservoirs at different NaCl concentrations.

scholarly journals Life cycle assessment of salinity gradient energy recovery by reverse electrodialysis in a seawater reverse osmosis desalination plant

2020 ◽  
Vol 4 (8) ◽  
pp. 4273-4284 ◽  
Author(s):  
Carolina Tristán ◽  
Marta Rumayor ◽  
Antonio Dominguez-Ramos ◽  
Marcos Fallanza ◽  
Raquel Ibáñez ◽  
...  
Keyword(s):  
Life Cycle Assessment ◽  
Life Cycle ◽  
Energy Recovery ◽  
Large Scale ◽  
Salinity Gradient ◽  
Reverse Electrodialysis ◽  
Desalination Plant ◽  
Gradient Energy ◽  
Seawater Reverse Osmosis ◽  
Reverse Osmosis Desalination

LCA of lab-scale and large-scale stand-alone RED stacks and an up-scaled RED system co-located with a SWRO desalination plant.

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

2017 ◽  
Vol 14 (2) ◽  
Author(s):  
Mohammadreza Nazemi ◽  
Jiankai Zhang ◽  
Marta C. Hatzell
Keyword(s):  
Energy Efficiency ◽  
Power Density ◽  
External Load ◽  
Salinity Gradient ◽  
Electrical Power ◽  
Ionic Current ◽  
Electrical Energy ◽  
Hydrogen Energy ◽  
Mixing Processes ◽  
Reverse Electrodialysis

There is an enormous potential for energy generation from the mixing of sea and river water at global estuaries. Here, we model 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 volume of high and low concentration solutions (1 L), the maximum energy extracted per volume of solution mixed occurred when the number of membranes is reduced, with the lowest number tested here being five membrane pairs. At this operating point, 0.32 kWh/m3 is extracted as electrical energy and 0.95 kWh/m3 as hydrogen energy. This corresponded to an electrical energy conversion efficiency of 15%, a hydrogen energy efficiency of 35%, and therefore, a total mixing energy efficiency of nearly 50%. As the number of membrane pairs increases from 5 to 20, the hydrogen power density decreases from 13.6 W/m2 to 2.4 W/m2 at optimum external load. In contrast, the electrical power density increases from 0.84 W/m2 to 2.2 W/m2. Optimum operation of RED depends significantly on the external load (external device). A small load will increase hydrogen energy while decreasing electrical energy. This trade-off is critical in order to optimally operate an RED cell for both hydrogen and electricity generation.

scholarly journals Chemical and Energy Recovery Alternatives in SWRO Desalination through Electro-Membrane Technologies

2021 ◽  
Vol 11 (17) ◽  
pp. 8100
Author(s):  
Marta Herrero-Gonzalez ◽  
Raquel Ibañez
Keyword(s):  
Renewable Energy ◽  
Salinity Gradient ◽  
Raw Material ◽  
Reverse Electrodialysis ◽  
Bipolar Membranes ◽  
Impact Reduction ◽  
Acid And Base ◽  
Readiness Level ◽  
Gradient Energy ◽  
Membrane Technologies

Electro-membrane technologies are versatile processes that could contribute towards more sustainable seawater reverse osmosis (SWRO) desalination in both freshwater production and brine management, facilitating the recovery of materials and energy and driving the introduction of the circular economy paradigm in the desalination industry. Besides the potential possibilities, the implementation of electro-membrane technologies remains a challenge. The aim of this work is to present and evaluate different alternatives for harvesting renewable energy and the recovery of chemicals on an SWRO facility by means of electro-membrane technology. Acid and base self-supply by means of electrodialysis with bipolar membranes is considered, together with salinity gradient energy harvesting by means of reverse electrodialysis and pH gradient energy by means of reverse electrodialysis with bipolar membranes. The potential benefits of the proposed alternatives rely on environmental impact reduction is three-fold: (a) water bodies protection, as direct brine discharge is avoided, (b) improvements in the climate change indicator, as the recovery of renewable energy reduces the indirect emissions related to energy production, and (c) reduction of raw material consumption, as the main chemicals used in the facility are produced in-situ. Moreover, further development towards an increase in their technology readiness level (TRL) and cost reduction are the main challenges to face.

scholarly journals Hydrogen production from industrial wastewaters: An integrated reverse electrodialysis - Water electrolysis energy system

2018 ◽  
Vol 203 ◽  
pp. 418-426 ◽  
Author(s):  
Ramato Ashu Tufa ◽  
Jaromír Hnát ◽  
Michal Němeček ◽  
Roman Kodým ◽  
Efrem Curcio ◽  
...  
Keyword(s):  
Hydrogen Production ◽  
Water Electrolysis ◽  
Energy System ◽  
Reverse Electrodialysis ◽  
Industrial Wastewaters
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