Choice of Reactor Performance

Unwanted byproducts usually cannot be converted back to useful products or raw materials. The reaction to unwanted byproducts creates both raw materials costs due to the raw materials that are wasted in their formation and environmental costs for their disposal. Thus, maximum selectivity is required for the chosen reactor conversion. The objectives at this stage can be summarized as follows  

For batch reactors, account must be taken of the time required to achieve a given conversion. Batch cycle time is addressed later. 

Raw materials costs usually will dominate the economics of the process. Because of this, when dealing with multiple 

Consider the system of parallel reactions from Equations 5.64 and 5.65. A high conversion in the reactor tends to decrease CFEED. Thus  

Multiple reactions in series producing byproduct. Consider the system of series reactions from Equation 5.68. Selectivity for series reactions of the types given in Equation 5.7 to 5.9 is increased by low concentrations of reactants involved in the secondary reactions. In the preceding example, this means reactor operation with a low concentration of PRODUCT, in other words, with low conversion. For series reactions, a significant reduction in selectivity is likely as the conversion increases. 

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