1. Property of Beehive Engineering Ideality of a CSTR Jordan H. Nelson

2. Property of Beehive Engineering Brief Overview Introduction – General CSTR Information Three Questions Experimental Conclusions

3. Property of Beehive Engineering ItemDescription 1Mixing Point 2 3 4Mixing Points 5Water Bath Inlet and Outlet 6Four Wall Mounted Baffles 7Mixer Drive 8Marine Type Impeller 9CSTR Vessel 10Water Bath Vessel Schematic of the CSTR

4. Property of Beehive Engineering 3 Questions? Where is the best mixing in the CSTR? Where is the best mixing in the CSTR? What is τ mean and how does it compare to τ ideal ? What is τ mean and how does it compare to τ ideal ? What configuration of PFR-CSTR will produce the greatest conversion? What configuration of PFR-CSTR will produce the greatest conversion?

5. Property of Beehive Engineering Where is the Best Mixing? Impeller selection Impeller selection Food Dye Test Food Dye Test Dead Zones Dead Zones Impeller Speed Impeller Speed

6. Property of Beehive Engineering Rushton ImpellerMarine Impeller Flow Patterns of different impellers

7. Property of Beehive Engineering τ Mean vs τ Ideal ? τ Mean – Measured mean residence time τ Mean – Measured mean residence time The amount of time a molecule spends in the reactor The amount of time a molecule spends in the reactor τ Ideal – Ideal residence time is calculated from the following equation τ Ideal – Ideal residence time is calculated from the following equation

8. Property of Beehive Engineering Experiment Fill reactor with low concentration salt (baseline) Fill reactor with low concentration salt (baseline) Spike reactor at most ideal mixing Spike reactor at most ideal mixing Create spike concentration at least one order of magnitude larger than baseline Create spike concentration at least one order of magnitude larger than baseline Measure change in conductivity over time Measure change in conductivity over time Run experiment at different impeller speeds Run experiment at different impeller speeds

9. Property of Beehive Engineering Yikes! Plot of Concentration vs Time with Error

10. Property of Beehive Engineering Measured Concentration over time in the CSTR.

11. Property of Beehive Engineering RTD Function E(t) Measured concentrations are used to create the residence time distribution function Measured concentrations are used to create the residence time distribution function

12. Property of Beehive Engineering Plot of an ideal residence time distribution function

13. Property of Beehive Engineering Residence time distributions

14. Property of Beehive Engineering Mean Residence Time Using E(t) the following equations produce the mean residence time Using E(t) the following equations produce the mean residence time

15. Property of Beehive Engineering Comparison of Residence Times RPM Mean Residence Time Standard DeviationSigma Sigma/ Tau 15357.5711.58206.870.58 30358.1411.58206.350.58 Ideal CSTR466.975.90

16. Property of Beehive Engineering Loss of Data Over an hour of data was lost from Opto 22 Over an hour of data was lost from Opto 22 Calculation of Reynolds number over 4000 (Turbulent) Calculation of Reynolds number over 4000 (Turbulent) Equation applies to a baffled CSTR Equation applies to a baffled CSTR RPM speed of 300 obtained full turbulence RPM speed of 300 obtained full turbulence

17. Property of Beehive Engineering CSTR-PFR Configurations? Schematic of arrangements Schematic of arrangements Levenspiel Plot Levenspiel Plot Conduct saponification reaction in the reactor at different RPM’s Conduct saponification reaction in the reactor at different RPM’s Use Equimolar flow rates and concentrations of reactants Use Equimolar flow rates and concentrations of reactants Quench reaction with a HCl and titrate with NaOH Quench reaction with a HCl and titrate with NaOH

18. Property of Beehive Engineering Series Reactor with CSTR Before PFR.

19. Property of Beehive Engineering Series Reactor with PFR Before CSTR.

20. Property of Beehive Engineering

21. CSTR-PFR Configurations? Schematic of arrangements Schematic of arrangements Levenspiel Plot Levenspiel Plot Conduct saponification reaction in the reactor at different RPM’s Conduct saponification reaction in the reactor at different RPM’s Use Equimolar flow rates and concentrations of reactants Use Equimolar flow rates and concentrations of reactants Quench reaction with a HCl and titrate with NaOH Quench reaction with a HCl and titrate with NaOH

22. Property of Beehive Engineering Measured Conversion for PFR-CSTR Configuration Speed (RPM) Conversion (%) Conversion Error (%) 3019.7+/-4.30 6021.7+/-3.91 20021.2+/-4.00 40024.3+/-3.48 87524.7+/-3.41

23. Property of Beehive Engineering Measured Conversion for CSTR-PFR Configuration Speed (RPM) Conversion (%) Conversion Error (%) 3021.5 +/-3.94 6021.2 +/-4.00 20021.4 +/-3.97 40020.9 +/-4.06 87521.5 +/-3.94

24. Property of Beehive Engineering 3 Questions? Where is the best mixing in the CSTR? Where is the best mixing in the CSTR? What is τ mean and how does it compare to τ ideal ? What is τ mean and how does it compare to τ ideal ? What configuration of PFR-CSTR will produce the greatest conversion? What configuration of PFR-CSTR will produce the greatest conversion?

25. Property of Beehive Engineering Conclusions Better mixing for a Rushton impeller is below the impeller Better mixing for a Rushton impeller is below the impeller The reactor is far from ideal at low impeller speeds The reactor is far from ideal at low impeller speeds The PFR-CSTR arrangement provided better conversions The PFR-CSTR arrangement provided better conversions Run the PFR-CSTR reactor at RPM’s of higher than 300 Run the PFR-CSTR reactor at RPM’s of higher than 300

26. Property of Beehive Engineering Opportunities Run the experiment again to obtain the lost residence time values Run the experiment again to obtain the lost residence time values Run the saponification reaction at higher temperatures Run the saponification reaction at higher temperatures Exit sampling stream should be at the bottom of the reactor Exit sampling stream should be at the bottom of the reactor

27. Property of Beehive Engineering Acknowledgements Taryn Herrera Taryn Herrera Robert Bohman Robert Bohman Michael Vanderhooft Michael Vanderhooft Dr. Francis V. Hanson Dr. Francis V. Hanson Dr. Misha Skliar Dr. Misha Skliar

28. Property of Beehive Engineering REFERENCES REFERENCES De Nevers, Noel, Fluid Mechanics, McGraw Hill, New York N.Y. (2005) De Nevers, Noel, Fluid Mechanics, McGraw Hill, New York N.Y. (2005) Fogler, H. Scott, Elements of Chemical Reaction Engineering, Prentice Hall, Upper Saddle River, N.J. (1999) Fogler, H. Scott, Elements of Chemical Reaction Engineering, Prentice Hall, Upper Saddle River, N.J. (1999) Havorka, R.B., and Kendall H.B. “Tubular Reactor at Low Flow Rates.” Chemical Engineering Progress, Vol. 56. No. 8 (1960). Havorka, R.B., and Kendall H.B. “Tubular Reactor at Low Flow Rates.” Chemical Engineering Progress, Vol. 56. No. 8 (1960). Ring, Terry A, Choi, Byung S., Wan, Bin., Phyliw, Susan., and Dhanasekharan, Kumar. “Residence Time Distributions in a Stirred Tank-Comparison of CFD Predictions with Experiments.” Industrial and Engineering Chemistry. (2003). Ring, Terry A, Choi, Byung S., Wan, Bin., Phyliw, Susan., and Dhanasekharan, Kumar. “Residence Time Distributions in a Stirred Tank-Comparison of CFD Predictions with Experiments.” Industrial and Engineering Chemistry. (2003). Ring, Terry A, Choi, Byung S., Wan, Bin., Phyliw, Susan., and Dhanasekharan, Kumar. “Predicting Residence Time Distribution using Fluent” Fluent Magazine. (2003). Ring, Terry A, Choi, Byung S., Wan, Bin., Phyliw, Susan., and Dhanasekharan, Kumar. “Predicting Residence Time Distribution using Fluent” Fluent Magazine. (2003).

29. Property of Beehive Engineering What to expect from your CSTR.

30. Property of Beehive Engineering Question?

31. Design Equations

32. Property of Beehive Engineering Design Equations