Optimization of Reactor Conversion for Single Reactions

Consider again the simple process in Fig. 4.1 in which FEED is reacted to PRODUCT via the reaction 

The effluent from the reactor contains both PRODUCT and unreacted FEED which must be separated in a distillation column. Unreacted FEED is recycled to the reactor via a pump if the recycle is liquid or a compressor if the recycle is vapor. 

Optimization of the system can be carried out by minimizing a cost function or maximizing economic potential EP defined by (see App. A) 

EP = value of products - raw materials costs - annualized capital cost - energy cost 

Plots of economic potential versus reactor conversion allow the optimal reactor conversion for a given flowsheet to be identified (Fig. 8.2). Although this approach allows the location of the optimum to be found, it does not give any indication of why the optimum occurs where it does. 

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