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Cyclones 121

Table 8
Equation (54) Parameters for Costs of Large Stacks
Lining Diameter (ft) a b
s s
Carbon steel 15 0.0120 0.811
316 L stainless 20 0.0108 0.851
Steel in top 30 0.0114 0.882
Section 40 0.0137 0.885
Acid resistant 15 0.00602 0.952
Firebrick 20 0.00562 0.984
30 0.00551 1.027
40 0.00633 1.036
Source: ref. 31.

However, the cost of small (e.g., 50–100 ft) FRP stacks can be roughly estimated as
150% of the cost of FRP ductwork for the same diameter and length. Similarly, the cost
of small carbon steel and stainless-steel stacks is also approx 150% of the cost of cor-
responding ductwork (31,32).
For larger stacks (200–600 ft), the cost is typically quite high, ranging from US$
1,000,000 to US$ 5,000,000 for some applications. Equation (54) and Table 8 can be
used to obtain costs of large stacks:

P = a H b s (54)
stack s stack
6
where P is the total capital cost of large stack (10 US$), H is the stack height
stack stack
(ft), and a and b refer to Table 8.
s s
3.5. Damper Purchase Cost
Dampers are commonly used to divert airflow in many industrial systems. Two types
of damper are discussed: backflow and two-way diverter valve dampers. The cost of
backflow dampers for duct diameters between 10 and 36 in. is given by
0.944
P damp = 7.4d duct (55)
where P is the cost of the damper (February 1988 US$) and d is the ductwork
damp duct
diameter (in.).
The cost of a two-way diverter valve for ductwork diameters between 13 and 40 in.
is given by

P = 4.846d 1.50 (56)
divert duct
where P is the cost of the two-way diverter valve (February 1988 US$) and d is
divert duct
the ductwork diameter (in.).
3.6. Calculation of Present and Future Costs

For the purposes of this handbook, auxiliary equipment is defined to include the cost of
fans, ductwork, stacks, dampers, and cyclones (if necessary) that commonly accompany