Packed columns generalized pressure drop

Loosely packed columns generally are inefficient. A column that is too tightly packed gives excessive pressure drop or may even become completely plugged because the support particles have been broken and fines are present. Applied Science Laboratories, Inc. has prepared a used column packing guide which is reproduced in Table 2.7. A column packed within 10% of the values shown in the table will provide satisfactory efficiency. 

The drop in pressure with the depth of packing is a key design variable, particularly for columns in vacuum service. The most reliable correlation is the generalized pressure-drop correlation of Leva25 as refined by Eckert,11 which is referred to as the Eckert model. This correlation, presented in Fig. 13-7 is of the form... 

Figure 4.5 Generalized pressure-drop correlation for packed beds. (Generated using the Packed Column Calculator, version 1.1, Katmar Software, 1998.)...

A generalized pressure drop correlation for packed columns with counter-current flow has been derived by Sherwood et al. [6] and adapted by Lobo et al. 

Figure 14.3.a-2 Generalized pressure drop correlation for packed columns with countercurrent flow. Parameter curves pressure drop, in inches water per foot (from Eckert [76]). 

The packing factors given in Table 1-4 are for use with these generalized pressure drop correlations (Figures 1-15 and 1-16). These packing factors have been determined from experimental pressure-drop data therefore, they are empirical rather than theoretical in nature. The use of pressure drop to determine column size is discussed in detail in Chapter 3. 

In contrast to randomly filled packing elements, the pressure drop for single gas flow Apo/H is generally reduced here as the column diameter ds is increased, whilst the gas capacity in the packing system remains the same. It follows from this that the resistance coefficient / is dependent on the column diameter ds in packed columns up to a certain diameter ds- According to the manufacturer Sulzer [16], it is only after... 

Fig. 24. Generalized method using log scales for estimating packed column flooding and pressure drop, AP, in kPa/m g = gravitational constant, 9.81 m/s t = kinematic viscosity in mm /s (= cSt) E, G have units of kg/(m s) are in kg/m and the packing factor, F, in can be found in...

Example 13 Packed Column Pressure Drop Air and water are flowing coiinterciirrently through a bed of 2-inch metal Pali rings. The air mass velocity is 2.03 kg/s-m (1500 Ihs/hr-fd), and the liquid mass velocity is 12.20 kg/s-m (9000 Ihs/hr-fr). Calculate the pressure drop hy the generalized pres-... 

---