Page 69 - Packed bed columns for absorption, desorption, rectification and direct heat transfer
P. 69
64
(227)
Taking into account equation (133), the relation between NTUOG
NTUQL, on one side, and NTUQ and NTU L on the other, can be obtained
(228)
. NTU G l 0 NTU L NTU G A.NTU L
and
> > + ^=^ + ^ (2M )
NTU L m NTU G NTU L NTU G NTU L
or
= ^SS. , (230)
NTU OL =yNTU OG
4 A
where A = — is called absorption factor. The value 4 is the ratio between the
molar flow rates of the liquid and of the gas phase.
By analogy with equation (224), it can be written
H = NTU^Jmj^ = NTU ol.HTU OL =
= NTU G.HTU G=NTU l.HTU l
where
(232)
La
-5 - , (233)
k aa
