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248 Lawrence K. Wang et al.

the air will be required. Such pretreatment of the air will affect two important design
parameters:
1. Maximum flow rate at actual conditions (Q ) = 100,000 acfm
e,a
2. Temperature (T ) = 400°F
e
D. Projected Venturi Pressure Drop
The suppliers of the Venturi scrubber system supplies the operating data curves (see
Fig. 5). These curves can be used to estimate the pressure drop, P , for the proposed
v
Venturi scrubber, at a given removal efficiency.
P = 47 in. H O
v 2
Also previously noted, if this pressure drop exceeds 80 in. H O, alternative control
2
technology needs to be considered, as the Venturi scrubber will most likely not
achieve the desired removal efficiency.
E. Proposed Material of Construction
Selection of material used to actually fabricate a Venturi scrubber is normally recom-
mended by the system supplier. A useful first estimate of the type of material required
can also be made by consulting Table 14.
Material of construction = 316L stainless steel
F. Proposed Venturi Scrubber Sizing
Performance curves supplied by system suppliers may be derived for saturated emis-
sion stream flow rate (Q ). If so, Q may be determined:
e,s e,s
Q = [Q (T + 460) / (T + 460)] + Q (28)
e,s e,a e,s e w
where Q is the saturated emission stream flow rate (acfm), T is the temperature of
e,s e,s
the saturation emission stream (°F), T is the temperature of the emission stream at
e
inlet air (°F), Q is the actual emission flow rate from Eq. (24) (acfm), and Q is the
e,a w
3
volume of water added (ft /min or cfm).
T is estimated to be 127°F using the psychrometric chart shown in Fig. 4 with values
e,s
for L and T . The inlet lb of H O per lb of dry air (L ) is determined by convert-
w,a e 2 w,a
ing M (now known to be 5%) from percent volume to the lb of H O per lb of dry air
e 2
as follows.
L = (M / 100) (18/29) = (5/100) (18/29) = 0.031 lb H O / lb dry air (Fig. 4)
w,a e 2
The adiabatic saturation line is determined on the psychrometric chart by determining
the intersection of the humidity (L = 0.031) and the inlet emission stream tempera-
w,a
ture (T = 400°F). This adiabatic saturation line is followed to the left until it intersects
e
the 100% relative saturation line. At this intersection, the temperature of the saturat-
ed emission (T ) is read from the ordinate and the saturated emission L is read from
e,s w,s
the abscissa.
T = 127ºF
e,s
Q = Q (D ) (L − L ) (1/D ) (29)
w e,ad e w,s w,a w
where

Q = (1 − L ) Q = (1 − 0.031) (110,000) = 106,590 acfm (29a)
e,ad w,a e,a