Significance of Pressure Drop for Packed Column Design

Significance of Pressure Drop for Packed Column Design 

It is important to know the total pressure drop Ap of the irrigated packed bed when designing packed columns for gas/liquid systems in counter-current flow of the phases. In absorption as weU as desorption processes, the total pressure drop Ap of the packing determines the blower capacity and thus the major part of the operating costs of the process. In rectihcation, the sum of the top pressure pT and the total pressure drop Ap gives the bottom pressure pw, which determines the bottom temperature tw- The bottom temperature, in turn, determines the effective temperature difference, at a given heating medium temperature, at which the reboiler in the distillation column must be operated. 

The total pressure drop of the packing Ap at a known packing height H, the calculation of which was the topic of studies such as [13-15], is given by the product Ap = (Ap/H)-H, in which the quotient Ap/H stands for the pressure drop per 1 m height of the packed bed. 

Based on the known pressure drop Ap/H and the specific pressure drop Ap/nt, Eq. (1-4) can be used to calculate the theoretical separation efficiency of the random or structured packing nt/H, and therefore the total height of the packed bed H, if the number of theoretical stages nt is known. 

Chemische Technik/Verfahrenstechnik, DOI 10.1007/b98397 4, Springer-Verlag Berlin Heidelberg 2010 

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