Page 141 - Air Pollution Control Engineering

03_chap_wang.qxd 05/05/2004 12:48 pm Page 120
120 José Renato Coury et al.

Table 7
Equation (48) Parameters
Parameter Group 1 Group 2
Static pressure (in.) 2–22 20–32
Flow rate (acfm) 700–27000 2000–27000
Fan wheel diameter (in.) 19.125–50.5 19.25–36.5
a 6.41 22.1
f
b 1.81 1.55
f

where P is the cost of the fan motor, belt, and starter (February 1988 US$) and hp
motor
is the motor horsepower (1 ≤ hp ≤ 7.5). For high-horsepower requirements,
P motor = 94.7hp 0.821 (50)

where P is the cost of the fan motor, belt, and starter (February 1988 US$) and hp
motor
is the motor horsepower (7.5 ≤ hp ≤ 250).
3.3. Ductwork Purchase Cost
The cost of ductwork for a HAP control system is typically a function of material
(e.g., PVC, FRP), diameter, and length. To obtain the duct diameter requirement as a
function of the emission stream flow rate at actual conditions (Q ), use Eq. (51). This
a
equation assumes a duct velocity (U ) of 2000 ft/min.
duct
 4 Q  0.5
d = 12  a  = 0.3028 Q 0.5 (51)
duct π a
 U duct 
The cost of PVC ductwork in US$/ft for diameters between 6 and 24 in. is provided
using
P = a d b d (52)
PVCd d duct
where P is the cost of PVC ductwork (US$/ft [August 1988 US$]), d is the duct
PVCd duct
diameter (in.) (factor of 12 in./ft), a = 0.877 (6 ≤ d ≤ 12 in.) or 0.0745 (14 ≤ d ≤
d duct duct
24 in.), and b = 1.05 (6 ≤ d ≤ 12 in.) or 1.98 (14 ≤ d ≤ 24 in.).
d duct duct
For a FRP duct having a diameter between 2 and 5 ft, Eq. (53) can be used to obtain
the duct cost. Note that the duct diameter is in units of feet for this equation.
P = 24D (53)
FRPd duct
where P is the cost of the FRP ductwork (US$/ft [August 1988 US$]) and D is
FRPd duct
the duct diameter (ft).
It is more difficult to obtain ductwork costs for carbon steel and stainless-steel con-
struction because ductwork of this material is almost always custom fabricated. For
more information on these costs, consult refs. 31 and 32.
3.4. Stack Purchase Cost
Because stacks are usually custom fabricated, it is also difficult to obtain stack cost
correlations. Smaller stacks are typically sections of straight ductwork with supports.