Evolutionary Design Optimization of an Alkaline Water Electrolysis Cell for Hydrogen Production

Hydrogen is an excellent energy source for long-term storage and free of greenhouse gases. However, its high production cost remains an obstacle to its advancement. The two main parameters contributing to the high cost include the cost of electricity and the cost of initial financial investment. It is possible to reduce the latter by the optimization of system design and operation conditions, allowing the reduction of the cell voltage. Because the CAPEX (initial cost divided by total hydrogen production of the electrolyzer) decreases according to current density but the OPEX (operating cost depending on the cell voltage) increases depending on the current density, there exists an optimal current density. In this paper, a genetic algorithm has been developed to find the optimal evolution parameters and to determine an optimum electrolyzer design. The optimal current density has been increased by 10% and the hydrogen cost has been decreased by 1%.

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CFD Modeling and Experimental Validation of an Alkaline Water Electrolysis Cell for Hydrogen Production

Processes ◽

10.3390/pr8121634 ◽

2020 ◽

Vol 8 (12) ◽

pp. 1634

Author(s):

Jesús Rodríguez ◽

Ernesto Amores

Keyword(s):

Fluid Dynamics ◽

Hydrogen Production ◽

Current Density ◽

Fluid Dynamic ◽

Water Electrolysis ◽

Operating Conditions ◽

Cfd Modeling ◽

Electrolysis Cell ◽

Alkaline Water Electrolysis ◽

Alkaline Water

Although alkaline water electrolysis (AWE) is the most widespread technology for hydrogen production by electrolysis, its electrochemical and fluid dynamic optimization has rarely been addressed simultaneously using Computational Fluid Dynamics (CFD) simulation. In this regard, a two-dimensional (2D) CFD model of an AWE cell has been developed using COMSOL® software and then experimentally validated. The model involves transport equations for both liquid and gas phases as well as equations for the electric current conservation. This multiphysics approach allows the model to simultaneously analyze the fluid dynamic and electrochemical phenomena involved in an electrolysis cell. The electrical response was evaluated in terms of polarization curve (voltage vs. current density) at different operating conditions: temperature, electrolyte conductivity, and electrode-diaphragm distance. For all cases, the model fits very well with the experimental data with an error of less than 1% for the polarization curves. Moreover, the model successfully simulates the changes on gas profiles along the cell, according to current density, electrolyte flow rate, and electrode-diaphragm distance. The combination of electrochemical and fluid dynamics studies provides comprehensive information and makes the model a promising tool for electrolysis cell design.

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Multiphysical Models for Hydrogen Production Using NaOH and Stainless Steel Electrodes in Alkaline Electrolysis Cell

Journal of Combustion ◽

10.1155/2021/6673494 ◽

2021 ◽

Vol 2021 ◽

pp. 1-11

Author(s):

Ivan Newen Aquigeh ◽

Merlin Zacharie Ayissi ◽

Dieudonné Bitondo

Keyword(s):

Stainless Steel ◽

Hydrogen Production ◽

Supporting Electrolyte ◽

Cell Voltage ◽

Water Electrolysis ◽

Maximum Error ◽

Electrolysis Cell ◽

Alkaline Water Electrolysis ◽

Interelectrode Gap ◽

Alkaline Electrolysis

The cell voltage in alkaline water electrolysis cells remains high despite the fact that water electrolysis is a cleaner and simpler method of hydrogen production. A multiphysical model for the cell voltage of a single cell electrolyzer was realized based on a combination of current-voltage models, simulation of electrolyzers in intermittent operation (SIMELINT), existing experimental data, and data from the experiment conducted in the course of this work. The equipment used NaOH as supporting electrolyte and stainless steel as electrodes. Different electrolyte concentrations, interelectrode gaps, and electrolyte types were applied and the cell voltages recorded. Concentrations of 60 wt% NaOH produced lowest range of cell voltage (1.15–2.67 V); an interelectrode gap of 0.5 cm also presented the lowest cell voltage (1.14–2.71 V). The distilled water from air conditioning led to a minimum cell voltage (1.18–2.78 V). The water from a factory presented the highest flow rate (12.48 × 10−1cm3/min). It was found that the cell voltage of the alkaline electrolyzer was reduced considerably by reducing the interelectrode gap to 0.5 cm and using electrolytes that produce less bubbles. A maximum error of 1.5% was found between the mathematical model and experimental model, indicating that the model is reliable.

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Development of an operation strategy for hydrogen production using solar PV energy based on fluid dynamic aspects

Open Engineering ◽

10.1515/eng-2017-0020 ◽

2017 ◽

Vol 7 (1) ◽

pp. 141-152 ◽

Cited By ~ 5

Author(s):

Ernesto Amores ◽

Jesús Rodríguez ◽

José Oviedo ◽

Antonio de Lucas-Consuegra

Keyword(s):

Hydrogen Production ◽

Fluid Dynamic ◽

Renewable Energy Sources ◽

Water Electrolysis ◽

Weather Conditions ◽

Energy Sources ◽

Electrolysis Cell ◽

Operation Strategy ◽

Solar Pv ◽

Alkaline Water Electrolysis

AbstractAlkaline water electrolysis powered by renewable energy sources is one of the most promising strategies for environmentally friendly hydrogen production. However, wind and solar energy sources are highly dependent on weather conditions. As a result, power fluctuations affect the electrolyzer and cause several negative effects. Considering these limiting effects which reduce the water electrolysis efficiency, a novel operation strategy is proposed in this study. It is based on pumping the electrolyte according to the current density supplied by a solar PV module, in order to achieve the suitable fluid dynamics conditions in an electrolysis cell. To this aim, a mathematical model including the influence of electrode-membrane distance, temperature and electrolyte flow rate has been developed and used as optimization tool. The obtained results confirm the convenience of the selected strategy, especially when the electrolyzer is powered by renewable energies.

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3D CFD Electrochemical and Heat Transfer Model of an Internally Manifolded Solid Oxide Electrolysis Cell

Volume 4: Energy Systems Analysis, Thermodynamics and Sustainability; Combustion Science and Engineering; Nanoengineering for Energy, Parts A and B ◽

10.1115/imece2011-62582 ◽

2011 ◽

Author(s):

Grant L. Hawkes ◽

James E. O’Brien ◽

Greg G. Tao

Keyword(s):

Heat Transfer ◽

Hydrogen Production ◽

Current Density ◽

Operating Conditions ◽

Solid Oxide ◽

Electrolysis Cell ◽

Transfer Model ◽

Gas Composition ◽

Solid Oxide Electrolysis ◽

Solid Oxide Electrolysis Cell

A three-dimensional computational fluid dynamics (CFD) and electrochemical model has been created to model high-temperature electrolysis cell performance and steam electrolysis in an internally manifolded planar solid oxide electrolysis cell (SOEC) stack. This design is being evaluated experimentally at the Idaho National Laboratory (INL) for hydrogen production from nuclear power and process heat. Mass, momentum, energy, and species conservation are numerically solved by means of the commercial CFD code FLUENT. A solid-oxide fuel cell (SOFC) model adds the electrochemical reactions and loss mechanisms and computation of the electric field throughout the cell. The FLUENT SOFC user-defined subroutine was modified for this work to allow for operation in the SOEC mode. Model results provide detailed profiles of temperature, operating potential, steam-electrode gas composition, oxygen-electrode gas composition, current density and hydrogen production over a range of stack operating conditions. Results will be presented for a five-cell stack configuration that simulates the geometry of five-cell stack tests performed at the INL and at Materials and System Research, Inc. (MSRI). Results will also be presented for a single cell that simulates conditions in the middle of a large stack. Flow enters the stack from the bottom, distributes through the inlet plenum, flows across the cells, gathers in the outlet plenum and flows downward making an upside-down “U” shaped flow pattern. Flow and concentration variations exist downstream of the inlet holes. Predicted mean outlet hydrogen and steam concentrations vary linearly with current density, as expected. Contour plots of local electrolyte temperature, current density, and Nernst potential indicate the effects of heat transfer, reaction cooling/heating, and change in local gas composition. Results are discussed for using this design in the electrolysis mode. Discussion of thermal neutral voltage, enthalpy of reaction, hydrogen production, cell thermal efficiency, cell electrical efficiency, and Gibbs free energy are discussed and reported herein.

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3D CFD Electrochemical and Heat Transfer Model of an Integrated-Planar Solid Oxide Electrolysis Cell

Volume 8: Energy Systems: Analysis, Thermodynamics and Sustainability; Sustainable Products and Processes ◽

10.1115/imece2008-68866 ◽

2008 ◽

Author(s):

Grant Hawkes ◽

James O’Brien

Keyword(s):

Heat Transfer ◽

Hydrogen Production ◽

Current Density ◽

Solid Oxide ◽

Electrolysis Cell ◽

Gas Composition ◽

Ceramic Tube ◽

Nernst Potential ◽

Solid Oxide Electrolysis ◽

Solid Oxide Electrolysis Cell

A three-dimensional computational fluid dynamics (CFD) electrochemical model has been created to assess high-temperature electrolysis performance of an Integrated Planar porous-tube-supported Solid Oxide Electrolysis Cell (IP-SOEC). The model includes ten integrated planar cells in a segmented-in-series geometry deposited on a flattened ceramic support tube. Mass, momentum, energy, and species conservation and transport are provided via the core features of the commercial CFD code FLUENT. A solid-oxide fuel cell (SOFC) module adds the electrochemical reactions and loss mechanisms and computation of the electric field throughout the cell. The FLUENT SOFC user-defined subroutine was modified for this work to allow for operation in the SOEC mode. Model results provide detailed profiles of temperature, Nernst potential, operating potential, activation over-potential, anode-side gas composition, cathode-side gas composition, current density and hydrogen production over a range of stack operating conditions. Predicted mean outlet hydrogen and steam concentrations vary linearly with current density, as expected. Contour plots of local electrolyte temperature, current density, and Nernst potential indicated the effects of heat transfer, endothermic reaction, Ohmic heating, and change in local gas composition. Results are discussed for using this design in the electrolysis mode. Discussion of thermal neutral voltage, enthalpy of reaction, hydrogen production is reported herein. Predictions show negative pressure in the H2 electrode, indicating a possible limit of H2O diffusion through the ceramic tube. Minimum temperatures occur in the fuel and air downstream corner of the ceramic tube for voltages below the thermal neutral point.

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CFD Model of a Planar Solid Oxide Electrolysis Cell: Base Case and Variations

ASME/JSME 2007 Thermal Engineering Heat Transfer Summer Conference, Volume 3 ◽

10.1115/ht2007-32310 ◽

2007 ◽

Cited By ~ 1

Author(s):

Grant Hawkes ◽

Russell Jones

Keyword(s):

Hydrogen Production ◽

Current Density ◽

Solid Oxide ◽

Cathode Side ◽

Base Case ◽

Electrolysis Cell ◽

Gas Composition ◽

Cfd Model ◽

Solid Oxide Electrolysis ◽

Solid Oxide Electrolysis Cell

A three-dimensional computational fluid dynamics (CFD) model has been created to model high-temperature steam electrolysis in a planar solid oxide electrolysis cell (SOEC). The model represents a single cell, as it would exist in an electrolysis stack. Details of the model geometry are specific to a stack that was fabricated by Ceramatec, Inc. and tested at the Idaho National Laboratory. Mass, momentum, energy, and species conservation and transport are provided via the core features of the commercial CFD code FLUENT. A solid-oxide fuel cell (SOFC) module adds the electrochemical reactions and loss mechanisms and computation of the electric field throughout the cell. The FLUENT SOFC user-defined subroutine was modified for this work to allow for operation in the SOEC mode. Model results provide detailed profiles of temperature, Nernst potential, operating potential, activation over-potential, anode-side gas composition, cathode-side gas composition, current density and hydrogen production over a range of stack operating conditions. Mean model results are shown to compare favorably with experimental results obtained from an actual ten-cell stack tested at INL. Mean per-cell area-specific-resistance (ASR) values decrease with increasing current density, consistent with experimental data. Predicted mean outlet hydrogen and steam concentrations vary linearly with current density, as expected. Effects of variations in operating temperature, gas flow rate, cathode and anode exchange current density, and contact resistance from the base case are presented. Discussion of thermal neutral voltage, enthalpy of reaction, hydrogen production, cell thermal efficiency, cell electrical efficiency, and Gibbs free energy are discussed and reported herein.

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A Photoelectrochemical Model of Proton Exchange Water Electrolysis for Hydrogen Production

Journal of Heat Transfer ◽

10.1115/1.2789722 ◽

2008 ◽

Vol 130 (4) ◽

Cited By ~ 17

Author(s):

Jianhu Nie ◽

Yitung Chen ◽

Robert F. Boehm ◽

Shanthi Katukota

Keyword(s):

Hydrogen Production ◽

Polymer Electrolyte ◽

Current Density ◽

Power Supply ◽

Proton Exchange Membrane ◽

Water Electrolysis ◽

Electrical Circuit ◽

Proton Exchange ◽

Illumination Intensity ◽

Electrolysis Cell

A photoelectrochemical model for hydrogen production from water electrolysis using proton exchange membrane is proposed based on Butler-Volmer kinetics for electrodes and transport resistance in the polymer electrolyte. An equivalent electrical circuit analogy is proposed for the sequential kinetic and transport resistances. The model provides a relation between the applied terminal voltage of electrolysis cell and the current density in terms of Nernst potential, exchange current densities, and conductivity of polymer electrolyte. Effects of temperature on the voltage, power supply, and hydrogen production are examined with the developed model. Increasing temperature will reduce the required power supply and increase the hydrogen production. An increase of about 11% is achieved by varying the temperature from 30°Cto80°C. The required power supply decreases as the illumination intensity becomes greater. The power supply due to the cathode overpotential does not change too much with the illumination intensity. Effects of the illumination intensity can be observed as the current density is relatively small for the examined illumination intensities.

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Stability Evaluation for Polymer Electrolyte Membrane Eletrolyzer

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.260-261.443 ◽

2012 ◽

Vol 260-261 ◽

pp. 443-448 ◽

Cited By ~ 1

Author(s):

Hong Gun Kim ◽

Hee Jae Shin ◽

Yun Ju Cha ◽

Sun Ho Ko ◽

Hyun Woo Kim ◽

...

Keyword(s):

Flow Field ◽

Polymer Electrolyte ◽

Current Density ◽

Polymer Electrolyte Membrane ◽

Cell Voltage ◽

Average Cell ◽

Electrolyte Membrane ◽

Field Plate ◽

Pem Electrolyzer ◽

The Cost

Recently, polymer electrolyte membrane (PEM) electrolyzers consist of the layered structure of membrane and electrode assembly (MEA), titanium flow field plate, gasket, end plate, and others. Among these components, MEA and titanium flow field plate take account for most of the device cost. The cost and time for manufacturing device can be reduced with the gasket-integrated 3-D mesh-applied PEM electrolyzer (Fig. 3), while maintaining the same performance as that of the existing titanium flow field plate devices. The 3-D mesh is found to perform the roles of the existing flow plate which ensures the smooth fluid flow and uniform power supply. The voltage shows 19.3V at current density (0.5 A/cm2), a little lower than 19.6V that is 10 times of 1.96V which is the average cell voltage at the same current density. In addition, hydrogen production and stability for performance are equal to or higher than that of the device for titanium flow field plate.

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Numerical Modeling of Electrochemical Process for Hydrogen Production From PEM Electrolyzer Cell

ASME 2007 Energy Sustainability Conference ◽

10.1115/es2007-36108 ◽

2007 ◽

Cited By ~ 1

Author(s):

Shanthi P. Katukota ◽

Jianhu Nie ◽

Yitung Chen ◽

Robert F. Boehm ◽

Hsuan-Tsung Hsieh

Keyword(s):

Hydrogen Production ◽

Current Density ◽

Mass Fraction ◽

Hydrogen Reduction ◽

Current Collector ◽

Proton Exchange ◽

Porous Electrodes ◽

Electrochemical Kinetics ◽

Cathode Side ◽

Electrolysis Cell

Numerical simulations of proton exchange water electrolysis for hydrogen production were performed for the purpose of examining the phenomena occurring within the proton exchange membranes (PEM) water splitting cell. A two-dimensional steady-state isothermal model of the cell has been developed. Finite element method was used to solve the multicomponent transport model coupled with flow in porous medium, charge balance and electrochemical kinetics. The Maxwell-Stefan equation is applied for the multi-component diffusion and convection in water distribution electrodes. The Butler-Volmer kinetic equation is used to obtain the local current density distribution at the catalyst reactive boundaries. Darcy’s law was applied for the flow of species in the porous electrodes. Parametric studies are performed based on appropriate mass balances, transport, and electrochemical kinetics applied to the electrolysis cell. There are significant current spikes present at the corners of the current collector. The current density varies significantly in the cell, being highest at the corners of the current collector. As the water on the anode side flows from the inlet to the outlet, the mass fraction of oxygen increases. This is the effect of oxygen concentration due to the effect oxidation of water. On the cathode side, as the mass fraction of water decreases there is little variation in the hydrogen mass fraction content due to the effect of hydrogen reduction.

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