CALCULATION OF HETP : NORTONS RELATION:

There is the Norton correlation for modern random dumped packings for distillations at pressures of up to 200 psia:

ln HETP = n -0.187 ln s + 0.213 ln µ

where:

HETP, ft
n has been tabulated as function of type and size of packing
s is the liquid phase surface tension, dyne/cm
µ is the liquid viscosity, cP


I think Norton (Chemical Process)has changed hands twice and utimately become Koch-Glitch. The(K-G) provide a lot of downloads and data for packing on the net. As per my understanding, HETP is normally a function of only liquid viscosity, surface tension and Packing characteristics. K-G even provide a software for column calculations both tray and packing provided you input the liquid and gas data.Right now I have the following for IMTP packing from some notes on the net:

For liq viscosity >0.4cp
 HETP = EXP(B)* (sigma)^(-0.187) * (mu)^0.213
For liq viscosity <0.4cp
 HETP = EXP(A)* (sigma)^(-0.157) * (1.78)^(mu)(yes! to the power  of (mu)!!)
The surface tension and the viscosity values are at the operating temperature. 

Packing-Size 15     25    40    50    70 nominal size mm)
A        2.84 3.05    3.23    3.50    3.87
B        3.36 3.57    3.75    4.03    4.39

Typically, the maximum number of theoretical stages in a single bed is kept to 12 (range: 8:20).  The height between beds is about 30 inches