16 Nov. 2001:
>dear Bill,
>
>Thank you for your email.

At 05:26 PM 11/16/2001 -0500, you wrote:
Sigurd,

I enjoyed your paper on self-optimizing control of the Eastman process.
Your use of the very small purge to control pressure results in some
very large pressure swings (100 kPa) compared to my use of the large "C"
feed stream. I would expect many shutdowns on high pressure for large
disturbances.


>As far as I know we never had any such problems.
>This is also the same strategy as used by Ricker (1996). 
>Jim Downs has also looked at our control strategy and indicated that it should work fine.

The other atypical feature is no control of inert composition. Did you
test your scheme for changes in the amount of inert in the feed? Do you
have some plots showing how the inert concentration changes?


>Yes, disturbance 8 (included in the paper) includes variations in the composition of B
>(inert).
>As can be seen this is handled nicely - espescially with decoupling included.
>
>The plot of inert (B) are very similar (but opposite) to those shown for component C,
>
>see for example,
>http://www.chembio.ntnu.no/users/skoge/publications/2001/te/Hovland/Diplom/Grafer/sim1purge.gif
>
>-Sigurd

Good to see you in Reno.

Bill Luyben 

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