Dynamic Performance for Ramp Disturbances

The ramp disturbances are imposed on the process using each of the three control structures. The temperature and valve-position controllers are tuned by running relay-feedback tests. Deadtimes of 1 min are used in these loops. Temperature controller TCI is tuned at the normal design feed flow rate (4000 kmol/h), and Tyreus-Luyben tuning give Kc = 31 and Ti = 9.2min. 

The TC2 temperature controller is tuned at the low-flow conditions since this is where it is active. Ziegler-Nichols tuning is used so that the tightest possible temperature control is achieved. Base and reflux-drum level controllers are proportional with Kq = 2. 

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