1. Copper Functioning as an Oxygen Carrier in Chemical Looping Combustion
Authors:
Richard Baraki,
Dr. Gabor Konya,
Dr. Edward M. Eyring.
Departments of:
Chemistry and
Chemical Engineering

2. Chemical Looping Combustion

3. Observed Oxygen Carrier
Copper
2 Cu(s) + O2(g)↔ 2 CuO(s)

4. Method of Analysis Thermogravimetric Analysis ThermoFisher HP-TGA
TA Q500
ThermoFisher HP-TGA

5. Copper Overall oxidation 2 Cu(s) + O2(g)↔ 2 CuO(s)
Cu → Cu(I) Cu(s) + O2(g)↔ 2Cu2O(s)
Cu(I) → Cu(II) Cu2O(s) + O2(g)↔ 4 CuO(s)

6. 2 days of looping (200+ loops) @ 850 °C

7. Looping

8. Cu(I) →Cu(II)
Cu(I) 850 °C
Fitted Cu(I) 850 °C

9. Residual plot
Residual of Y, (mg)
Independent Variable, (sec)

10. Pseudo first order equation
First-order reaction
r = -d[A]/dt = k[A]
k = rate constant
A = amount of copper
Pseudo first order reaction for
r = k[A][B]1/2 = k΄[A]
k΄ = k[B]1/2
A= amount of copper
B= partial pressure of oxygen

11. Method of fit Fitted Parameters Fixed Parameter
y = Wf + (Wi - Wf) * e(-k * (t-t0))
Fitted Parameters
Wf - final weight of oxide
Wi - initial weight of oxide
k- rate constant
Fixed Parameter
t0- indicates start of reaction

12. Shifting k values (TA-Q500)

13. Shifting k values (HP-TGA)

14. Cu2O/CuO/Cu2O system

15. Temperature effects
Sintering
Tamman Temperature
Change the pics here

16. Pressure using HP-TGA Pressure plots Oxygen analyzer 1 atm 9 atm 16atm

17. Pseudo first order equation
First-order reaction
r = -d[A]/dt = k[A]
k = rate constant
A = amount of copper
Pseudo first order reaction for
r = k[A][B]1/2 = k΄[A]
k΄ = k[B]1/2
A= amount of copper
B= partial pressure of oxygen

18. Experimental Procedure
Sample loaded into quartz bucket
200mg copper powder
Chamber closed and purged with pure nitrogen 15+ min
Temperature ramp from 21°C to 950°C in pure nitrogen gas at 25°C/min
Given experiment, pressure build up
At desired temperature and pressure, air is introduced

19. Observations Stoichiometric conversion
Rate at which sample is being oxidized

20. Oxidation at different pressures
Cu →CuO

21. Observations
Stoichiometric conversion

22. Oxidation at different pressures
Cu →CuO

23. Observations Stoichiometric conversion
Rate at which sample is being oxidized

24. Oxidation at different pressures
Cu →CuO

25. Reaction Rates for Range of Mass Increases of 101 to 105%:
Decrease in rate with increasing pressure indicative of diffusional limitations

26. Theoretical rates versus experimental rates based on the pseudo-first order model, to be revisited after experimental constraints eliminated
Cu →CuO

27. Oxygen analyzer
Gas cylinders
HP-TGA

28. Oxygen concentrations at exit of reactor corresponding to HP-TGA plots previously shown. Failure to reach 21% to be explored
Oxygen analysis of
Cu →CuO
Cu →CuO

29. Oxygen analysis of
Cu →CuO

30. Conclusion Pseudo first order model does not fit Cu/Cu2O/CuO system
Data indicate diffusional limitations

31. Acknowledgements Department of Energy Dana Overacker Kevin Tucker
under Award Number DE-NT
Dana Overacker
Kevin Tucker
Blake R. Wilde