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Including Levels in MPC to Improve Distillation Control Control
Authors:
Haitao
Huang and
James B. Riggs
ABSTRACT
This work examines the effects of including levels into MPC for
distillation control via rigorous
simulation of two different columns: a depropanizer and a propane/propylene
splitter (C3 splitter). Three different MPC implementations for
distillation control were compared: regular implementation in which levels are
controlled by PI regulatory controllers; direct implementation in which the
levels are controlled by MPC directly by manipulating flow rates; and cascade
implementation in which MPC moves the setpoints to the regulatory level
controllers. The results show that directly including levels in MPC improves
composition control performance significantly for fast responding distillation
columns. The cascade implementation is recommended for columns that exhibit
ill-conditioning for the [L,V] control configuration or for columns that exhibit
a large time to obtain steady state.
Publication Information: I&ECR,
Vol 41, No. 16, Aug 2002
Corresponding Author: J.B. Riggs
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