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580 presentation v3

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580 presentation v3

  1. 1. Effects of Electrolyte Flow Rate, Flow Channel Thickness, and Current Density on the Regenerative Hydrogen-Vanadium Flow Battery By: Christopher Graves Master’s Candidate 580: Technical Review Presentation
  2. 2. Motivation • The shift to renewable sources of power requires a power storage method to store the power that was generated during off peak hours. • Redox flow batteries have emerged as a possible candidate for full scale implementation. • The all vanadium flow battery appears to be the device closest to grid scale implementation
  3. 3. Redox Flow Batteries 77
  4. 4. All Vanadium Flow Battery • Vanadium has multiple oxidations states. – 5 oxidation states • Since vanadium is the only redox elements in the system, cross contamination is not as large an issue as in multiple electrolyte batteries.
  5. 5. All Vanadium Flow Battery • A major capital cost of the All Vanadium Flow Battery is the cost of the vanadium.
  6. 6. All Vanadium Flow Battery
  7. 7. Regenerative Hydrogen Vanadium Flow Battery 8
  8. 8. Regenerative Hydrogen Vanadium Flow Battery Chemistry 8
  9. 9. Regenerative Hydrogen Vanadium Flow Battery • The Hydrogen Vanadium benefits: – Decreased dependency on vanadium • The Hydrogen Vanadium Battery retains all of the benefits of the all Vanadium battery
  10. 10. Purpose • Analyze 3 variables for effects on capital cost of the Regenerative Hydrogen Vanadium Flow Battery – Electrolyte (vanadium) flow rate – Flow Channel thickness – Current density
  11. 11. Method • Three variables were selected to be varied in a simulation. • The project was presented as the capstone project for the senior class. • The students used a previously developed model to determine the device parameters and device cost. • The sizing method was determined by Moore et al.
  12. 12. Method • The technology was costed using tables and methods laid out in Dr. Gael Ulrich’s textbook Chemical Engineering: Process Design and Economics A Practical Guide and information provided by Moore et al.
  13. 13. Assumptions • The pressure drop due to the manifold spreading the vanadium electrolyte into the cells would be equal to the gains when the flows were rejoined. • The cells were modeled as fully developed linear flow infinite plates. • The pressure drop in the different cells is assumed the same, so the pressure drop of the liquid flow through one cell is equal to the total pressure drop.
  14. 14. Assumptions • The costs and additional effects of enlarging the flow channel are neglected. • It is assumed the current density is independent of the channel thickness. • The flow rate of hydrogen is the flow rate required to keep the hydrogen gas at 1 atm. • Hydrogen is the dominant gas in the gas flow stream. The presence of any other substance is negligible.
  15. 15. Electrolyte Flow Rate • The flow rate of the vanadium electrolyte has an effect on the overall efficiency of the battery. • In order to generate any power, and consistently achieve positive voltage, a minimum flow rate is required. • The analyzed flow rates were 20 and 50 times the minimum theoretical flow rate.
  16. 16. Efficiency VS Flow Rate and Current Density 1 1.5 2 2.5 3 3.5 4 4.5 5 x 10 4 0.65 0.7 0.75 0.8 0.85 0.9 0.95 1 FlowRateof Vanadium(L/s) Efficiency(%) 100mA/cm2 200mA/cm2 300mA/cm2 400mA/cm2
  17. 17. Effects of Electrolyte Flow Rate on Capital Cost
  18. 18. Effects of Electrolyte Flow Rate on Capital Cost • The observed effects of the flow rate on the price of the battery were minimal.
  19. 19. Flow Channel Thickness • Traditionally the cost of pumps are a small percentage of the total device cost. • The analyzed flow channel thickness were: 0.5 cm, 1 cm, 1.5 cm, and 2 cm.
  20. 20. Effects of Flow Channel Thickness on Capital Cost
  21. 21. Effects of Flow Channel Thickness on Capital Cost • A small effect of the flow channel was observed. • The thicker flow channels resulted in the smallest cost, however, the returns diminished after the 1 cm thickness.
  22. 22. Current Density • The current density is assumed to be constant through all the stacks • The current density is a parameter that determines many other important parameters such as flow rate and the total number of required cells
  23. 23. Current Density • An efficiency is associated with the 4 current densities that were analyzed • The 4 current densities analyzed were: 100 mA/cm², 200 mA/cm², 300 mA/cm², and 400 mA/cm².
  24. 24. Current Density Table 1. The efficiency of the due to electrical resistances at different current densities. Current Density (mA/cm2 ) Efficiency 100 93.54% 200 87.16% 300 80.77% 400 74.40%
  25. 25. Effect of Current Density on Capital Cost
  26. 26. Effect of Current Density on Capital Cost
  27. 27. Effect of Current Density on Capital Cost • The optimal current density is a function of the power capacity of the battery • The current density has the greatest effect on the over cost of the device
  28. 28. Conclusions • Flow rates have a small effect on the overall efficiency. • The flow rate has a small overall impact on the overall cost of the device.
  29. 29. Conclusions • The channel thickness had the least impact on the overall device cost of the three variables analyzed. • Larger flow channels resulted in decreased overall costs. • Extremely thin channel thicknesses will result in drastically increasing costs.
  30. 30. Conclusions • The current density had the greatest effect of the three variables. • The ideal current density is a function of the power capacity of the battery. – 200 mA/cm² for a 4 MW battery, 300 mA/cm² for a 6 MW battery.
  31. 31. Conclusions • The ideal current density would be dependant on the desired power of the. • The optimal flow channel is around a thickness of 2 cm. • The flow rate should be at least 20 times the minimum theoretical flow rate.
  32. 32. Acknowledgements • My primary advisor – Dr. Robert Counce • Dr. Jack Watson • Dr. Thomas Zawodzinski
  33. 33. Acknowledgement • Mark Moore
  34. 34. References • REFERENCES • 1 D. Aaron, Z. J. Tang, A. B. Papandrew, and T. A. Zawodzinski, 'Polarization Curve Analysis of All- Vanadium Redox Flow Batteries', Journal of Applied Electrochemistry, 41 (2011), 1175-82. • 2 Christie John Geankoplis, Transport Processes and Separation Process Principles. 4 edn (Bernard Goodwin, 2003), p. 1026. • 3 'Hydraulic Diameter of Ducts and Tubes', 2014) < http://www.engineeringtoolbox.com/hydraulic-equivalent-diameter-d_458.html> [Accessed June 4 2014]. • 4 M. Moore, J. S. Watson, T. A. Zawodzinski, M. Q. Zhang, and R. M. Counce, 'Capital Cost Sensitivity Analysis of an All-Vanadium Redox-Flow Battery', Industrial Electrochemistry and Electrochemical Engineering (General) - 220th Ecs Meeting, 41 (2012), 1-19. • 5 M. Skyllas-Kazacos, M. H. Chakrabarti, S. A. Hajimolana, F. S. Mjalli, and M. Saleem, 'Progress in Flow Battery Research and Development', Journal of the Electrochemical Society, 158 (2011), R55-R79. • 6 A. Tang, S. M. Ting, J. Bao, and M. Skyllas-Kazacos, 'Thermal Modelling and Simulation of the All- Vanadium Redox Flow Battery', Journal of Power Sources, 203 (2012), 165-76. • 7 A. Z. Weber, M. M. Mench, J. P. Meyers, P. N. Ross, J. T. Gostick, and Q. H. Liu, 'Redox Flow Batteries: A Review', Journal of Applied Electrochemistry, 41 (2011), 1137-64. • 8 V. Yufit, B. Hale, M. Matian, P. Mazur, and N. P. Brandon, 'Development of a Regenerative Hydrogen- Vanadium Fuel Cell for Energy Storage Applications', Journal of the Electrochemical Society, 160 (2013), A856-A61.
  35. 35. Questions
  36. 36. Thank You For Your Time

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