Page 39 - Analysis, Synthesis and Design of Chemical Processes, Third Edition

Each utility is identified by the initials provided in Table 1.3. As an example, let us locate E-102 in
Figure 1.3. The notation, cw, associated with the nonprocess stream flowing into E-102 indicates that
cooling water is used as a coolant.

Electricity used to power motors and generators is an additional utility that is not identified directly on
the PFD or in Table 1.3 but is treated separately. Most of the utilities shown are related to equipment that
adds or removes heat within the process in order to control temperatures. This is common for most

chemical processes.

From the PFD in Figure 1.3, the identification of the process streams is clear. For small diagrams
containing only a few operations, the characteristics of the streams such as temperatures, pressures,

compositions, and flowrates can be shown directly on the figure, adjacent to the stream. This is not
practical for a more complex diagram. In this case, only the stream number is provided on the diagram.
This indexes the stream to information on a flow summary or stream table, which is often provided below
the process flow diagram. In this text the flow summary table is provided as a separate attachment to the
PFD.

The stream information that is normally given in a flow summary table is given in Table 1.4. It is divided
into two groups—required information and optional information—that may be important to specific
processes. The flow summary table, Figure 1.3, is given in Table 1.5 and contains all the required
information listed in Table 1.4.

Table 1.4 Information Provided in a Flow Summary