Calculation of potential and concentration gradients in trickle-bed electrodes producing hydrogen peroxide

1986 ◽  
Vol 51 (9) ◽  
pp. 1883-1898 ◽  
Author(s):  
Otomar Špalek
Keyword(s):  
Mathematical Model ◽  
Hydrogen Peroxide ◽  
Current Density ◽  
Potential Distribution ◽  
Current Flow ◽  
Anode Chamber ◽  
Current Yield ◽  
Concentration Gradients ◽  
Electrolyte Flow ◽  
Trickle Bed

A mathematical model for describing the trickle-bed electrode has been developed and used to calculate the potential distribution along the current flow and the hydrogen peroxide concentration profile along the electrolyte flow (normal to the direction of current). Polarization curves and dependences of the current yield of hydrogen peroxide and the peroxide losses due to the processes occurring (reduction, decomposition, and transport into the anode chamber) on the current density have also been calculated. A comparison is made between calculated and measured dependences of the current yield of hydrogen peroxide on the current density.

Potential distribution in a trickle-bed electrode

1989 ◽  
Vol 54 (12) ◽  
pp. 3144-3153
Author(s):  
Otomar Špalek ◽  
Karel Balogh
Keyword(s):  
Hydrogen Peroxide ◽  
Particle Size ◽  
Electrode Potential ◽  
Potential Distribution ◽  
Graphite Particle ◽  
Current Yield ◽  
Electrolyte Flow ◽  
Flow Rates ◽  
Voltage Loss ◽  
Trickle Bed

The performance of trickle-bed electrodes of crushed graphites in oxygen reduction to hydrogen peroxide has been investigated. Results are presented for the effects of the current density, gas and electrolyte flow rates, pressure, and graphite particle size on the electrode potential, voltage loss in the electrode material, and current yield of the process.

Porous electrodes for hydrogen peroxide preparation by oxygen reduction. The influence of temperature and pressure applied in preparation of the electrodes on their functional properties

1981 ◽  
Vol 46 (9) ◽  
pp. 2052-2059 ◽  
Author(s):  
Otomar Špalek ◽  
Jan Balej
Keyword(s):  
Hydrogen Peroxide ◽  
Carbon Black ◽  
Current Density ◽  
Porous Electrodes ◽  
Current Yield ◽  
Electric Resistance ◽  
Influence Of Temperature ◽  
Electrode Mass ◽  
Temperature And Pressure ◽  
Wetted Surface Area

The influence of the temperature and pressure applied in preparation of porous electrodes from Teflon-bonded carbon black on the hydrogen peroxide current yield and the current density was investigated. The porous structure, the wetted surface area of carbon black, and the electric resistance of the electrode mass were examined in order to establish the factors responsible for the varying electrode activity.

The influence of zinc electrode substrate, electrolyte flow rate and current density on zinc-nickel flow cell performance

2021 ◽  
Vol 373 ◽  
pp. 137890
Author(s):  
David P. Trudgeon ◽  
Adeline Loh ◽  
Habib Ullah ◽  
Xiaohong Li ◽  
Vladimir Yufit ◽  
...  
Keyword(s):  
Flow Rate ◽  
Current Density ◽  
Flow Cell ◽  
Cell Performance ◽  
Zinc Electrode ◽  
Electrolyte Flow ◽  
Zinc Nickel

A Numerical Investigation Into the Interaction Between Current Flow and Fuel Consumption in a Segmented-in-Series Tubular SOFC

2009 ◽  
Vol 6 (3) ◽  
Author(s):  
B. A. Haberman ◽  
A. J. Marquis
Keyword(s):  
Density Distribution ◽  
Fuel Consumption ◽  
Current Density ◽  
Current Flow ◽  
Flow Direction ◽  
Ionic Current ◽  
Leading Edge ◽  
Current Density Distribution ◽  
Fuel Flow ◽  
In Series

A typical segmented-in-series tubular solid oxide fuel cell (SOFC) consists of flattened ceramic support tubes with rows of electrochemical cells fabricated on their outer surfaces connected in series. It is desirable to design this type of SOFC to operate with a uniform electrolyte current density distribution to make the most efficient use of the available space and possibly to help minimize the onset of cell component degradation. Predicting the electrolyte current density distribution requires an understanding of the many physical and electrochemical processes occurring, and these are simulated using the newly developed SOHAB multiphysics computer code. Of particular interest is the interaction between the current flow within the cells and the consumption of fuel from an adjacent internal gas supply channel. Initial simulations showed that in the absence of fuel consumption, ionic current tends to concentrate near the leading edge of each electrolyte. Further simulations that included fuel consumption showed that the choice of fuel flow direction can have a strong effect on the current flow distribution. The electrolyte current density distribution is biased toward the upstream fuel flow direction because ionic current preferentially flows in regions rich in fuel. Thus the correct choice of fuel flow direction can lead to more uniform electrolyte current density distributions, and hence it is an important design consideration for tubular segmented-in-series SOFCs. Overall, it was found that the choice of fuel flow direction has a negligible effect on the output voltage of the fuel cells.

Magnetisation and Critical Currents in High Tc Powders

1987 ◽  
Vol 99 ◽  
Author(s):  
A. M. Campbell ◽  
A. D. Hibbs ◽  
J. Eberharde ◽  
S. Male ◽  
M. F. Ashby ◽  
...  
Keyword(s):  
Penetration Depth ◽  
Current Density ◽  
Current Flow ◽  
Theoretical Calculations ◽  
Hot Isostatic Pressing ◽  
Critical Currents ◽  
High Tc ◽  
Isostatic Pressing

ABSTRACTMagnetisation curves have been measured on powders of various sizes. The hysteresis decreases with size for articles smaller than 20μ showing that barriers to current flow are at least this far apart. The current density is 6×106 amps/cm2 at 1.5T and this is consistent with theoretical calculations of Jc. Inductive transitions are consistent with a penetration depth of about 0.5μ at 78K. The results of Hot Isostatic Pressing are also discussed.

Influence of hydrodynamics of electrolyte flow during electrochemical treatment on the quality of the treated surface

2021 ◽  
pp. 55-60
Author(s):  
Keyword(s):  
Electrical Conductivity ◽  
Current Density ◽  
Electrochemical Treatment ◽  
Flow Lines ◽  
Electrolyte Flow ◽  
Flow Rates ◽  
Average Flow ◽  
Electrochemical Processing ◽  
Interelectrode Gap

The features of the hydrodynamics of the electrolyte in the interelectrode gap during electrochemical processing of a profile axisymmetric workpiece are considered. The distribution of average flow rates and flow lines is calculated for a specified electrolyte supply. The nature and rate of the electrolyte flow are established. The unevenness of the current density is determined taking into account the change in the electrical conductivity of the electrolyte from heating and gas filling of the interelectrode gap, as well as the quality of the treated surface. Keywords: electrochemical treatment, roughness, electrolyte, electrical conductivity, gas filling. [email protected]

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