1. Stian Aaltvedt Supervisors: Sigurd Skogestad Johannes Jäschke
Specialization Project 2012: Optimal Operation of Parallel Systems
Stian Aaltvedt Supervisors: Sigurd Skogestad Johannes Jäschke
Stian Aaltvedt, Optimal Operation of Parallel Systems, Dec

2. THE JÄSCHKE TEMPERATURE
OPTIMAL OPERATION OF HEAT EXCHANGER NETWORKS ?

3. Optimal Operation of Heat Exchanger Networks …
Objective function ?
Equality constraints ?
Inequality constraints ?

4. Optimal Operation of Heat Exchanger Networks …

5. Optimal Operation of Heat Exchanger Networks … Equality constraints:
Equality constraints:
Jäschke Temperature

6. Optimal Operation of Heat Exchanger Networks … Equality constraints:
Equality constraints:
Jäschke Temperature
Inequality constraints:

7. Case Studies …

8. Case Studies … Disturbances: Inlet cold stream temperature T0
Inlet cold stream heat capacity w0
Inlet hot stream temperature Thi
Inlet hot stream heat capacity whi
Manipulated variable:
Stream split (w1 or w2)
Controlled variables:
Outlet temperature Tend
Heat exchanger size UAi

9. The procedure …
INITIAL DISTURBANCES
Optimize subject to object function and constraints
Optimized UA values
OPTIMAL DESIGN
JÄSCHKE
Outlet temperature from optimal design = outlet temperature from optimal opreation ?
OPTIMAL OPERATION

10. The Jäschke Temperatures …

11. Case 1 Results
GIVEN DATA

12. Case 1 Results
GIVEN DATA

13. Case 1 Results
GIVEN DATA

14. Case 2 Results
GIVEN DATA

15. Case 3 Results
GIVEN DATA

16. Case 3 Results
GIVEN DATA

17. Conclusions and Further Work
For steady state parallel systems:
The Jäschke Temperature showed good results compared to the optimal design
For real, dynamic systems:
Further investigation needed, including dynamic simulations

18. Thank you!