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Production and Capital Cost Estimation 57

Tanks
Filters, all types 1.4 Process (SS) 1.8

Gas holders 1.3 Process (Al) 2.0
Granulators for plastics 1.5 Storage (SS) 1.5

Storage (Al) 1.7
Storage (CS) 2.3
Field erected (SS) 1.2
Field erected (CS) 1.4
Heat exchangers
Turbines 1.5
Air cooled (CS) 2.5 Vessels, pressure (SS) 1.7
Coil in Shell (SS) 1.7 Vessels, pressure (CS) 2.8
Glass 2.2
Graphite 2.0
Plate (SS) 1.5
Plate (CS) 1.7
a. Direct cost = materials + labor = indirect factor x equipment cost
b. Carbon steel (CS)
c. Stainless steel (SS)
d. Shell material/tube material
Source: Adapted from Reference 35 with permission.

Correcting Equipment Cost for Size

Usually, the cost literature contains equipment costs for capacities other than what
is required. To scale the equipment cost to the required capacity, we usually as-
sume that its cost varies to some power, usually fractional, of its capacity. Thus,
the scaled cost will be

fQ 2 V
I ___ I (2.6)
I ——— I
iQi )

If we know the cost of a piece-of-equipment at one capacity and the capacity ex-
ponent, n, then we can calculate its cost at another capacity. We can find cost data
in References [10], [13], [15], [16], and [36]. More recent cost data are contained
in References [4], [30], [31], and [37]. Table 2.9 contains costs and capacity expo-
nents of some common equipment. The correlation range given in Table 2.9 gives
the size limits for each piece-of-equipment. You should not extrapolate Equation
2.6 too far beyond the limits specified. For example, from Table 2.9, the cost of a

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