Page 126 - Adsorption, Ion Exchange & Catalysis- 2007, Elsevier - Copy

Else_AIEC-INGLE_cH003.qxd 7/13/2006 1:45 PM Page 122
122 3. Heterogeneous Processes and Reactor Analysis

Another parameter, similar to fractional holdup but different in v is the volume frac- alue,
tion of solid and liquid in the slurry (K 1996; Kantarci oide, et al ., 2005).

V
S (3.172)
S
V
V
S L
V
S (3.173)
L
V
V
S L
In this def the term “slurry” is used to denote the phase consisting of the liquid
inition,
and the solid, and thus the term “b would be a more appropriate term to ubble-free slurry”
be used for this phase.
Smith (1981) uses the parameter V B , referred to in his book as “gas holdup, which is ”
defined as “the volume of bubbles per unit volume of liquid, which is different from the ”
fractional holdup v alue:

V G V G V tot V G V tot h G
V B (3.174)
V V V V V h
L L tot tot L L
Then, follo the “total gas holdup” is
wing Smith’
,
s terminology
VV V (3.175)
BL G
which is simply the total volume of gas in the reactor .
The fractional gas holdup can be easily measured from the height of the expanded col-
umn height Z f and the settled slurry height Z , i.e. the height of the column before aeration
s
(liquid volume plus solids volume) (DOE, 1985; NTIS, 1983):
Z Z
h f s (3.176)
G
Z
f
Define the mass concentration of solids in a slurry as

M
m S (3.177)
s
V
L
where V L is the volume of liquid then
M
V S (3.178)
L
m
s
and f inally
V S m s
(3.179)
V
L p