RTD in Tube Reactors with a Laminar Flow

In reactor tubes in which the flow velocity is low, the flow profiles deviate from that of the plug flow. The reason is that the Reynolds number, Re = wd/v (where w denotes the flow velocity in m/s, d is the diameter of the tube, and v is the kinematic viscosity), yields values that are typical for a laminar flow. The kinematic viscosity, v, is obtained from the dynamic viscosity, x, and density, p, of the flowing media (v = x/p). A typical boundary value for the Reynolds number is 2000 values below this indicate that the flow with a 

A reactor tube in which laminar flow conditions prevail can therefore be considered as a system of parallel, coupled PFRs, in which the residence time varies between fniin = 

FIGURE 4.17 Ceramic (left) and metallic (right) monolith structures. 

FIGURE 4.18 Laminar flow in circular tubes, volumetric flow rate  

The total volume flow, V, can even be defined as the multiplication of the average velocity by the cross-section A  

---