Page 21 - Chemical process engineering design and economics

Chapter 1

Plan EWWtkxi Process Design
I————————I——————————————I
6 months 9 months
Plant Design
I————————————I

15 months
Startup Routine Operation Routine Operation
|———|—————————|———+-
3 months «t restricted capacity at design capacity
Debottknecklng
Tlmeftom Conceptlonaf Stage to Routlrw Operation

Figure 1.1 Sample of a process and plant-design schedule.
Source: Ref. 17, with permission.

before completing plant construction. Usually, from the start to the time a plant
reaches design capacity may take anywhere from three to four years. [17].
Even after the plant has been successfully started, it will need constant atten-
tion to keep it operating smoothly and to improve its operation. This is the re-
sponsibility of the process engineer. Many of the skills that were used by the
process-design engineer are also utilized by the process engineer. A major activity
of the process engineer is the "debottlenecking" study to increase plant capacity,
in which the process is analyzed to determine what process unit limits the plant
capacity. When this unit is located, the process engineer will consider alternative
designs for increasing plant capacity.

PROCESS DESIGN

Our main goal is to develop techniques for solving problems in process design.
Process design generally proceeds in the following stages:

1. Developing process flow diagrams
2. Process circuit analysis
3. Sizing process units
4. Estimating production cost and profitability

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