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

2007 ◽  
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.

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

2007 ◽  
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.

A Photoelectrochemical Model of Proton Exchange Water Electrolysis for Hydrogen Production

2008 ◽  
Vol 130 (4) ◽  
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.

Fabrication and Performance Evaluation of Miniaturized Proton Exchange Membrane (PEM) Fuel Cells

2003 ◽  
Author(s):  
Tao Zhang ◽  
Pei-Wen Li ◽  
Qing-Ming Wang ◽  
Laura Schaefer ◽  
Minking K. Chyu
Keyword(s):  
Mass Transfer ◽  
Fuel Cells ◽  
Fuel Cell ◽  
Free Convection ◽  
Current Density ◽  
Pem Fuel Cells ◽  
Proton Exchange ◽  
Cathode Side ◽  
Ohmic Loss ◽  
Fuel Cell Performance

Two types of miniaturized PEM fuel cells are designed and characterized in comparison with a compact commercial fuel cell device in this paper. One has Nafion® membrane electrolyte sandwiched by two brass bipolar plates with micromachined meander-like gas channels. The cross-sectional area of the gas flow channel is approximately 250 by 250 (μm). The other uses the same Nafion® membrane and anode structure, but in stead of the brass plate, a thin stainless steel plate with perforated round holes is used at cathode side. The new cathode structure is expected to allow oxygen (air) being supplied by free-convection mass transfer. The characteristic curves of the fuel cell devices are measured. The activation loss and ohmic loss of the fuel cells have been estimated using empirical equations. Critical issues such as flow arrangement, water removing and air feeding modes concerning the fuel cell performance are investigated in this research. The experimental results demonstrate that the miniaturized fuel cell with free air convection mode is a simple and reliable way for fuel cell operation that could be employed in potential applications although the maximum achievable current density is less favorable due to limited mass transfer of oxygen (air). The relation between the fuel cell dimensions and the maximum achievable current density is also discussed with respect to free-convection mode of air feeding.

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

2020 ◽  
Vol 10 (23) ◽  
pp. 8425
Author(s):  
Damien Le Bideau ◽  
Olivier Chocron ◽  
Philippe Mandin ◽  
Patrice Kiener ◽  
Mohamed Benbouzid ◽  
...  
Keyword(s):  
Hydrogen Production ◽  
Current Density ◽  
Operating Cost ◽  
Cell Voltage ◽  
Electrolysis Cell ◽  
Alkaline Water Electrolysis ◽  
Financial Investment ◽  
Operation Conditions ◽  
Optimal Current ◽  
The Cost

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%.

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

Processes ◽  
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.

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

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.

The Effects of Feeding Configurations to Water Flooding and General Performance of a Proton Exchange Membrane Fuel Cell

2005 ◽  
Author(s):  
A. B. Mahmud Hasan ◽  
S. M. Guo ◽  
S. V. Ekkad
Keyword(s):  
Fuel Cell ◽  
Power Density ◽  
Current Density ◽  
Proton Exchange Membrane ◽  
Cell Voltage ◽  
Bipolar Plate ◽  
Proton Exchange ◽  
Water Flooding ◽  
Cathode Side ◽  
Exchange Membrane

The performance of a Proton Exchange Membrane Fuel Cell (PEMFC) using different feeding configurations has been studied. Three bipolar plates, namely serpentine, straight channel and interdigitated designs, were arranged in different combinations for the PEMFC anode and cathode sides. Nine combinations in total were tested under different flow rates, working temperatures and loadings. The cell voltage versus current density and the cell power density versus current density curves were obtained. After operating the PEMFC under high current densities, the cell was split and the water flooding in the feeding channels was visually inspected. Experimental results showed that for different feeding configurations, interdigitated bipolar plate in anode side and serpentine bipolar plate in cathode side had the best performance in terms of cell voltage-current density curve, power density output rate, percentage of flooded area in the feeding channels, the pattern of flooding and the fuel utilization rate.

Experimental Analysis of PEM Fuel Cells With Biomimetical Mixed Flows as Gas Distributors

2010 ◽  
Author(s):  
C. E. Damian-Ascencio ◽  
A. Herna´ndez-Guerrero ◽  
A. Alatorre-Ordaz ◽  
A. Cuauhtemoc-Rubio ◽  
F. Elizalde-Blancas
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Current Collector ◽  
Natural World ◽  
Pem Fuel Cells ◽  
Proton Exchange ◽  
Cathode Side ◽  
Anode Side ◽  
Collector Plate ◽  
Mixed Flows

A proton exchange membrane fuel cell (PEMFC) is an electrochemical device that converts the chemical energy from the gases into electrical energy. The PEMFCs consist of many parts, and the current collector plate is one of the key components among them. Channels in the bipolar plate distribute air on the cathode side and hydrogen on the anode side. Theoretically a fuel cell produces more current as more fuel is supplied. However the way in which the gases are supplied affects dramatically the performance of the cell. The present paper shows how the mixed flows improve the current density produced by fuel cells. Polarization and power density curves are presented. The results suggest that a flow with two levels of bifurcations is preferred for the anode side. This behavior is expected due to the similitude with the performance of the natural world in which geometries with this type of bifurcations transport the nutrients inside the tree leaves and plants.

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

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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