Gas Emission Control - Mathematics and Statistics for the Environment - page 458

Psi drop, m H 2 O/ft. of packing (in H 2 O /ft. packing)

0.5

0.2
0.1

0.125 (1.5)

Flooding
Line

0.808 (1.0)

0.05

G *2 FO µ 0.2

0.0416 (0.5)
0.0208(0.25)

ε =

0.02

P g P l g c

0.00808 (0.10)

0.01

0.00416 (0.05)

0.005

0.002

0.00 0.01 0.02

0.05 0.1 0.2 0.5 1 2 5 10

L P g

(---)(---) 0.5 (dimensionless)

G P l

FIGURE 16.8 Generalized flooding and psi drop correlation. (From USEPA, APTI Course 415: Control
of Gaseous Emissions , EPA 450/2-81-005, U.S. Environmental Protection Agency Air Pollution Training
Institute, Washington, DC, 1981, p. 4-23.)

1. Calculate the value of the horizontal axis (abscissa) of Figure 16.8 using Equation 16.3:

0.

L
G

×

P
P

Abscissa =

g
l

(16.3)

where
L = Mass flow rate of liquid stream.
G = Mass flow rate of gas stream.
P g = Gas density.
P l = Liquid density.

2. From the point on the abscissa, calculated in Equation 16.3, proceed up the graph to the
flooding line and read the ordinate ε.

3. Using Equation 16.4, calculate the gas flow rate at flooding and solve for G ′:

05 .

′ = ×××
×× ()

ε PPg

g l c

G (16.4)

φµ 02

.

F

l

where
G ′ = Mass flow rate of gas per unit cross-sectional area at flooding (lb/s-ft 2 ).
ε = Ordinate value in Figure 16.8.
P g = Density of gas stream (lb/ft 3 ).
P l = Density of absorbing liquid (lb/ft 3 ).
g c = Gravitational constant = 9.82 m/s 2 (32.2 ft/s 2 ).