Optimization of multifeed rate control profiles

The feed flow rates, Fi and F2, were discretized into a set of four piece-wise constant control actions. Each of them has an interval of two days. The initial volume which was the final volume of the identification process was 0.8L, and the initial population size was chosen to be 200. The optimization procedure using the GA was run for 200 generations. Optimal control profiles which were determined for two separate feeds of glucose and glutamine are shown in Figure 3.5. The optimal feeding rates actually started from day two of the culture. Glutamine was fed to the culture first at a high rate (0.46 L/d) from day two to day four, then followed by a lower rate (0.027 L/d). On the other hand, glucose was added at a lower rate (0.014 L/d) from day two to day four followed by a medium rate 0.035L/d).

The time required for the optimization step was about two hours which can also be ignored when compared to the 10 days culture time.

0.35

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Time (day)

Fig. 3.5. Feed rate profiles for identification (single-feed) and optimization (multi-feed), the single feed rate for identification is defined by Equation 3.7.

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Time (day)

Fig. 3.5. Feed rate profiles for identification (single-feed) and optimization (multi-feed), the single feed rate for identification is defined by Equation 3.7.

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