Wet Scrubbers for Emission Control - Mathematics and Statistics for the Environment - page 530

where
C f = Cunningham correction factor.
p p = Particle densit y.
v = Gas velocity at Venturi throat (ft/s).
d p = Particle diameter (ft).
d d = Droplet diameter (ft).
µ = Gas viscosity (lb/ft-s).

18.2.5.2 Infinite Throat Model
Another method for predicting particle collection efficiency in a Venturi scrubber is the infinite
throat model (Yung et al., 1977). This model is a refined version of the Calvert correlation given in
Calvert et al. (1972). The equations presented in the infinite throat model assume that the water in
the throat section of the Venturi captures all particles. Two studies found that this method correlated
very well with actual Venturi scrubber operating data (Calvert et al., 1972; Yung et al., 1977). The
equations listed in the model can be used to predict the penetration ( P t ) for one particle size or for
the overall penetration ( P t *), which is obtained by integrating over the entire particle-size distribu-
tion. The equations are provided below (USEPA, 1984c, p. 9-4):

05 .

07 . K

+− (

)

05 .

− 1 po

4 K 4 2502 . . K 1 + tan

po po

K 07 .

() =−

po

ln Pd B (18.6)

t p

K + 07 .

po

where
P t ( d p ) = Penetration for one particle size.
B = Parameter characterizing the liquid-to-gas ratio (dimensionless).
K po = Inertial parameter at throat entrance (dimensionless).

Note: Equation 18.6 was developed assuming that the Venturi scrubber has an infinite-sized throat
length ( l ). This is valid only when l in the following equation is greater than 2.0:

= 3
2

lC p
dp

tDg
dl

l

where
l = Throat length parameter (dimensionless).
l t = Venturi throat length (cm).
C D = Drag coefficient for the liquid at the throat entrance (dimensionless).
p g = Gas density (g/cm 3 ).
d d = Droplet diameter (cm).
p l = Liquid density (g/cm 3 ).

The following equation is known as the Nukiyama-Tanasawa equation:

50

) .

15

d =+ 91 8 .( LG / (18.7)

d

v

gt

where
d d = Droplet diameter (cm).
v gt = Gas velocity in the throat (cm/s).
L / G = Liquid-to-gas ratio (dimensionless).