Page 221 - Analysis, Synthesis and Design of Chemical Processes, Third Edition

Chapter 8 Estimation of Manufacturing Costs

The costs associated with the day-to-day operation of a chemical plant must be estimated before the
economic feasibility of a proposed process can be assessed. This chapter introduces the important factors
affecting the manufacturing cost and provides methods to estimate each factor. In order to estimate the

manufacturing cost, we need process information provided on the PFD, an estimate of the fixed capital
investment, and an estimate of the number of operators required to operate the plant. The fixed capital
investment is the same as either the total module cost or the grassroots cost defined in Chapter 7.
Manufacturing costs are expressed in units of dollars per unit time, in contrast to the capital costs, which
are expressed in dollars. How we treat these two costs, expressed in different units, to judge the
economic merit of a process is covered in Chapters 9 and 10.

8.1 Factors Affecting the Cost of Manufacturing a Chemical Product

There are many elements that influence the cost of manufacturing chemicals. A list of the important costs
involved, including a brief explanation of each cost, is given in Table 8.1.

Table 8.1 Factors Affecting the Cost of Manufacturing ( COM) for a Chemical Product (from
References [1, 2, and 3])