General Considerations Material, Energy and Momentum Balances

1 General Considerations Material, Energy, and Momentum Balances 

The process design of a PFR typically involves determining the size of a vessel required to achieve a specified rate of production. The size is initially determined as a volume, which must then be expressed in terms of, for example, the length and diameter of a cylindrical vessel, or length and number of tubes of a given size. Additional matters to consider are effects of temperature resulting from the energetics of the reaction, 

Equation 15.2-2 may also be written in terms of space time, r = V/q as 

Equation 15.2-1 may be written in various other forms, depending on the gradient to be determined, as illustrated in Example 15-1. 

Rewrite equation 15.2-1 as a differential equation representing the gradient of fA with respect to position (x) in a PFR, dfA/dx. (Integration of this form gives the conversion profile.) 

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