Ergun Equation For Packed Beds

Ergun Equation gives us the pressure drop along the length of a packed bed reactor at a given fluid velocity.

From Ergun Equation we can understand that the pressure drop in a packed bed depends on the size of the packing material, length of the bed and the density of the fluid. 

The Ergun equation is the sum of a viscous term, corresponding to the Kozeny-Carman equation (which was developed for lowly to moderately porous media), and an inertial term, corresponding to the Burke-Plummer equation (which was developed for highly porous media). 

The pressure drop in the pipes can be expressed as follows:

Pressure Drop (∆P) and the Rate Law

 

The above equations can be solved either by Analytical Methods - for simple systems like first order reactions, or by Numerical Methods.

Pressure Drop (∆P) in Reactor