Advertisement

Journal of Applied Electrochemistry

, Volume 37, Issue 8, pp 921–931 | Cite as

Prediction of shunt currents in a bipolar electrolyzer stack by difference calculus

  • Ravichandra S. JupudiEmail author
  • Guillermo Zappi
  • Richard Bourgeois
Original Paper

Abstract

A model for predicting shunt/leakage currents in a bipolar electrolyzer stack with dual electrolyte inlets and significant amount of gases in the outlet ports and manifold is presented. Model includes electrolyte, manifold and membrane separator as resistance components in the electric circuit analog of the stack. Activation overvoltage associated with electrodes is taken as Tafel-like. Current balance and potential balance equations are applied to the stack and difference calculus is employed to reduce the problem to a set of linear difference equations with constant coefficients. The model is validated with published results and the effect of each resistance component and number of cells on leakage currents in the stack is presented.

Keywords

Bipolar electrolyzer stack Hydrogen production Manifold current Membrane separator Shunt current 

List of symbols

Ae

Area of the electrode, m2

b

Constants in Eqs. 21 and 22

Cj

Independent constants to be determined from the boundary conditions

C5j

Constants in Eqs. 5358

d

Depth of the inlet/outlet ports, m

Dj

Constants that are functions of r j

E

Difference operator

Ej

Constants that are functions of r j

EC

Constant part of cell voltage, V

En

Cell voltage, V

Eo

Nernst potential, V

F

Faraday’s constant, 96487 C mol−1

Fj

Constants that are functions of r j

g

Function that accounts for the increase in electrical resistivity due to the presence of gases

h1

Width of the inlet/outlet port at the manifold end, m

h2

Width of the inlet/outlet port at the electrode end, m

in1

Cell current on the cathode side of the membrane, A

in2

Cell current on the anode side of the membrane, A

io

Exchange current on the electrode, A

I

Direct current applied to the stack, A

IS

Fraction of current lost in the form of parasitic currents

kn

Leakage current in the cathodic inlet/outlet ports, A

Kn

Current in the manifold connected to the cathode sides of the electrolyzer cells, A

ln

Leakage current in the anodic inlet/outlet ports, A

LA

Gap between anode and the membrane , m

LC

Gap between cathode and the membrane, m

LM

Distance between two successive outlet ports, m

Ln

Current in the manifold connected to the anode sides of the electrolyzer cells, A

LP

Thickness of the bipolar plate, m

LS

Thickness of the membrane, m

N

Number of cells in the stack

NM

McMullin number

rj

Roots of the characteristic equation

R

Universal gas constant, J mol −1K−1

T

Stack operating temperature, K

RA

Resistance in the inlet/outlet port on the anode side

RC

Resistance in the inlet/outlet port on the cathode side

Re1

Ohmic resistance in the cathodic electrolyte, Ω

Re2

Ohmic resistances in the anodic electrolyte, Ω

RM

Manifold resistance, Ω

RS

Resistance due to the membrane, Ω

Greek symbols

αA

Average volume fraction of O2

αC

Average volume fraction of H2

αeA

Average volume fraction of O2 in the anode outlet port and anode manifold

αeC

Average volume fraction of H2 in the cathode outlet port and cathode manifold

αo

Electrode transfer coefficient

η

Electrode over voltage

θ

Angle of the inlet/outlet port as shown in Fig. 3

ρ

Electrical resistivity of pure electrolyte

Subscripts

i

Pertaining to the inlet

e

Pertaining to the outlet

n

Pertaining to cell numbered n

A

Pertaining to the anode electrode

C

Pertaining to the cathode electrode

Superscripts

A

Pertaining to the anode electrode

C

Pertaining to the cathode electrode

Notes

Acknowledgements

The second and third authors of this paper gratefully acknowledge financial support provided by the U.S. Department of Energy under Award Number DE-FC-14223.

Disclaimer: "This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof."

References

  1. 1.
    Ulleberg O (2003) Int J Hydrogen Energy 28:21CrossRefGoogle Scholar
  2. 2.
    Yang MZ, Wu H, Robert Selman J (1989) J Appl Electrochem 19:247CrossRefGoogle Scholar
  3. 3.
    Kuhn AT, Booth JS (1980) J Appl Electrochem 10:233CrossRefGoogle Scholar
  4. 4.
    Katz M (1978) J Electrochem Soc 125(4):515CrossRefGoogle Scholar
  5. 5.
    Burnett JC, Danly DE (1979) AIChE Symposium Series 75(185):8Google Scholar
  6. 6.
    Dousek FP, Micka K (1993) J Appl Electrochem 23:241CrossRefGoogle Scholar
  7. 7.
    Rangarajan SK, Yegnanarayanan V (1997) Electochimica Acta 42:153CrossRefGoogle Scholar
  8. 8.
    Rangarajan SK, Yegnanarayanan V, Muthukumar M (1998) Electochimica Acta 44:491CrossRefGoogle Scholar
  9. 9.
    Mat MD, Aldas K, Ilegbusi OJ (2004) Int J Hydrogen Energy 29(10):1015CrossRefGoogle Scholar
  10. 10.
    Mat MD, Aldas K (2005) Int J Hydrogen Energy 30(4):411CrossRefGoogle Scholar
  11. 11.
    Maxwell JC (1881) A treatise on electricity and magnetism, 2nd edn. Clarendon Press, OxfordGoogle Scholar
  12. 12.
    Van Zee J, White RE, Watson AT (1986) J Electrochem Soc:Electrochem Sci Technol 133(3):501Google Scholar

Copyright information

© Springer Science+Business Media, Inc. 2007

Authors and Affiliations

  • Ravichandra S. Jupudi
    • 1
    Email author
  • Guillermo Zappi
    • 2
  • Richard Bourgeois
    • 2
  1. 1.Applied CFD LabGE Global Research, John F Welch Technology Centre Pvt LtdBangaloreIndia
  2. 2.GE Global Research CenterNiskayunaUSA

Personalised recommendations