Page 210 - Analysis, Synthesis and Design of Chemical Processes, Third Edition

This is the equipment cost at operating conditions:

(7.12)

This cost is calculated by taking the bare module cost, at base conditions, and subtracting the cost of the
equipment at the base conditions.

The incremental cost of equipment installation due to nonbase case conditions is

(7.13)

This cost is based on the incremental cost of equipment due to nonbase conditions multiplied by a factor,
(f P&I ), that accounts for the fraction of the installation cost that is associated with piping and
instrumentation. The values of f P&I are modified from Guthrie [9, 10] to account for an increase in the

level and cost of instrumentation that modern chemical plants enjoy compared with that at the time of
Guthrie’s work.

Equations 7.11 through 7.13 can be combined to give the following relationship:

(7.14)

Equation 7.13 is the same as Equation A.4, with B = – 1 – f P&I and B = 1 + f P&I .
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7.3.6 Algorithm for Calculating Bare Module Costs

The following six-step algorithm is used to estimate actual bare module costs for equipment from the
figures in Appendix A.

1. Using the correct figure in Appendix A (Figures A.1–A.17), or the data in Table A.1, obtain
for the desired piece of equipment. This is the purchased equipment cost for the base case
(carbon steel construction and near ambient pressure).

2. Find the correct relationship for the bare module factor. For exchangers, pumps, and vessels, use