Page 155 - Chemical engineering design

FLOW-SHEETING
AN 500
Water 2500
Total 3000 Water 5000 60°C H1 135
15°C
Total 5000
DM water
Steam
From 15°C 40°C F1
storages To dryer
60°C
CW
60°C
R1
Cat. 5 AN 5
Water 100 Water 300
Total 105 AN 50 Water 7300 Polymer 448
Water 2600 AN 45 Salts trace Equipment key
From Polymer 450 Polymer 2 Total 753
catalyst Salts 5 Salts 5 R1 Polymer reactor
prep Total 3105 Total 7352 H1 Water heater
F1 Vacuum filter
Figure 4.1. Flow-sheet: polymer production
4.2.4. Information to be included

The amount of information shown on a flow-sheet will depend on the custom and practice
of the particular design office. The list given below has therefore been divided into
essential items and optional items. The essential items must always be shown, the optional
items add to the usefulness of the flow-sheet but are not always included.

Essential information

1. Stream composition, either:
(i) the flow-rate of each individual component, kg/h, which is preferred, or
(ii) the stream composition as a weight fraction.
2. Total stream flow-rate, kg/h.
3. Stream temperature, degrees Celsius preferred.
4. Nominal operating pressure (the required operating pressure).

Optional information
1. Molar percentages composition.
2. Physical property data, mean values for the stream, such as:
3
(i) density, kg/m ,
2
(ii) viscosity, mN s/m .
3. Stream name, a brief, one or two-word, description of the nature of the stream, for
example “ACETONE COLUMN BOTTOMS”.
4. Stream enthalpy, kJ/h.

The stream physical properties are best estimated by the process engineer responsible for
the flow-sheet. If they are then shown on the flow-sheet, they are available for use by
the specialist design groups responsible for the subsequent detailed design. It is best that
each group use the same estimates, rather than each decide its own values.