Design equation constant fluid density

For constant fluid density the design equations for plug flow and batch reactors are mathematically identical in form with the space time and the holding time playing comparable roles (see Chapter 8). Consequently it is necessary to consider only the batch reactor case. The pertinent rate equations were solved previously in Section 5.3.1.1 to give the following results. 

The design equations for a CFSTR with perfect mixing, constant fluid density, and steady state operation are as follows. If u is the volumetric flowrate and K = k1/k2, relative reaction rate constant, where k1 k2, and k3 are the specific reaction rate constants for reactions 5-357, 5-358, and 5-359. The rate expressions of A, B, R, S, and T are... 

Chapter 2 developed a methodology for treating multiple and complex reactions in batch reactors. The methodology is now applied to piston flow reactors. Chapter 3 also generalizes the design equations for piston flow beyond the simple case of constant density and constant velocity. The key assumption of piston flow remains intact there must be complete mixing in the direction perpendicular to flow and no mixing in the direction of flow. The fluid density and reactor cross section are allowed to vary. The pressure drop in the reactor is calculated. Transpiration is briefly considered. Scaleup and scaledown techniques for tubular reactors are developed in some detail. 

Equations (3-23) and (3-24) are design equations for an ideal CSTR with a constant-density fluid. The lighter box around these equations indicates that they are not as general as Eqn. (3-21), which is not restricted to a constant-density fluid. Equations (3-23) and (3-24) apply to both homogeneous and heterogeneously catalyzed reactions, provided that t is calculated from the appropriate equation, either Eqn. (3-20) or Eqn. (3-22). 

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