1 Name, title of the presentation Master project: Control structure design for a sequence of distillation columns Tor Anders Marvik Supervisor: Sigurd Skogestad Co-supervisors: Vladimoros L. Minasidis Johannes Jäschke

2 Optimal control structure of two distillation colums in a sequence Varying marked conditions Computer model Active constraint regions Self-optimizing variables Region 1: V 2, V 1, x D2,B active Region 2: x D2,B active General/systematic approach?

3 The model Based on column A by Skogestad 41 tray Feed on tray 21 Assumtions: Constant pressure Constant relative volatility Constant molar flows, No vapor holdup, Equlibrium on all stages Total condenser Steady state model in Matlab Conditions from Jacobsen

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5 Jacobsen’s map

6 V 2, V 1, x D2,B active

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8 Approach to find self-optimizing variables? Brute force Null space HF=0 Exact local method Possible disturbances –F,q,zF, prices, CV candiates –Tray temparature, composition, L1, V1, D1, L2, V2 D2, B2 –Combination

9 Brute force

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11 Combinations as CV Combination of Temperature (As Roal Bræck Leer) –All stages –Every 5 th stage Ratio with feed flow

12 Size of the measurement error Temperature: 1 K Consentraiton:5% Flow: 10%

13 To do A LOT Standard approach Brute force  exact local method See how L changes to disturbances when the candiadate CV is fixed

14 Thank you Feedback and questions?