Jim Riggs from Texas Tech, who works on process control, will visit
Kjemiteknikk on 15 August 1996.
He will give a lecture on Distillation control.
Time: Thursday , 15 August, 10.30 - 11.30
Place: Kjemiblokk 4, lunsjrommet
Everyone is welcome to attend!
Abstract:
DISTILLATION CONTROL
James B. Riggs
Department of Chemical Engineering
Texas Tech University
Lubbock, Texas 79409
USA
Distillation control remains an idustrially important problem
since distillation columns many times directly affect energy usage,
production rates, and product uniformities. We have a long-term
effort at Texas Tech that is aimed at developing industry guidelines
for choosing manipulated/controlled variable pairings and for the
proper choice of conventional or advanced controls.
We are using detailed dynamic simulators for five industrial
columns in order to work toward our goal: a proplyene/propane
splitter, a xylene/toluene column, a refinery depropanizer, a
multi-component acetic acid column, and a refinery main fractionator.
In addition, additonal designs of each of the columns based upon the
various combinations of moderate purity (~2%) and high purity (~0.1%)
products will also be studied. Available results for the first three
column case studies will be presented.
Configuration selection for each design of each column will be
studied by comparing diagonal PI controller performance for feed
compositions upsets. In general, the choice of the configuration has
been shown to have a dominate effect upon control performance and the
optimal configuration has been shown to depend upon the column type,
product purities, and the relative importance of the two products.
In addition, the robustness of the tuning used for each configuration was
tested by using reboiler duty upsets.
The optimal configuration in each case was used to compare a
conventional PI controller with a PI controller with a simple decoupler,
a model predictive controller, and a nonlinear controller. Each controller
was tested for a sinusoidal feed composition upset by measuring the
resulting product variablities over a full range of disturbance
frequencies.
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Sigurd Skogestad, Professor Fax: +47-7359-4080
Chemical Engineering Phone: +47-7359-4154
Norwegian University of Science and Technology Home: +47-7393-6855
N-7034 Trondheim e-mail: skoge@kjemi.unit.no
Norway http://www.kjemi.unit.no/~skoge
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