Geir Stian Landsverk (geir.stian.landsverk@itk.ntnu.no)
Mon, 03 Apr 2000 15:14:38 +0100
Heisann!
NB! Seminaret er flyttet, både tid og sted!!!
Alle PROST'ere ønskes velkommen til seminar
tirsdag 4 april kl. 15.15 -16.00
i rom B-343, 3.etg Elektrobygning B (lunchrom teknisk kybernetikk).
Foredraget er ved Duncan Coffey, Carnegie-Mellon University.
Se sammendrag under for mere informasjon, og
http://www.itk.ntnu.no/groups/PROST/seminars.html for vårprogrammet.
mvh
Geir Stian
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Distillation stability using passivity and thermodynamics
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Abstract:
Distillation is one of the most important unit operations in the
chemical process industry. The stability of distillation systems
has always been difficult to determine due to the nonlinear
natural of the unit operation. Previous work in the area has had
limited success and no theory has been able to show the stability
criteria for a general multicomponent distillation column. With a
better understanding of the stability criteria, distillation
control systems can be implemented to ensure stability and greater
control performance. In this work a detailed model is used to
evaluate the stability criteria of multicomponent distillation.
The model uses both temperature and pressure as driving forces for
energy and mass flows, along with weir formulas for the flow of
liquid between stages. The temperature and pressure driving
forces are then linked to a passivity based approach to analysis
using a thermodynamics based storage function. The analysis is
done by algebraically de-coupling the mass flows from the energy
and component flows. The stability criteria for the mass flows are
shown from a Eulerian, or fixed reference frame, and the energy
and component flow criteria from a Lagrangian, or moving reference
frame. The stability criteria for the flows within the column can
be used in the design stages to ensure stable dynamic behavior.
The results show that as long as the resistance to liquid flow is
equal or decreases down the column the system will be stable.
These results differ from work that has shown output
multiplicities in open loop distillation. The conclusions will
focus on the differences between these results and why they
appear.
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Geir Stian Landsverk
Dr.ing. student - Department of Engineering Cybernetics
Norvegian University of Science and Technology
7491 TRONDHEIM, NORWAY
Phone:++(47) 7359 4386 (office), ++(47) 7388 9310 (private)
E-mail: Geir.S.Landsverk@itk.ntnu.no
http://www.itk.ntnu.no/ansatte/Landsverk_Geir/
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