Page 130 - Plant design and economics for chemical engineers

106 PLANT DESIGN AND ECONOMICS FOR CHEMICAL ENGINEERS

20. Review the benzene storage system shown on page 107 in which benzene enters tank
T-l01 through a 4-in. line L-l01 and is subsequently pumped out through pumps
P-1OlA and B at 35 atm into a 3-in. line L-102. The accompanying table shows that
part of a HAZOP study of line G102 has been completed. Provide the missing
information to complete the study.

HAZOP for line G102
Possible Possible
Guide word pnwm CBUSt? consequence Action required
More Temperature - Pump seal Install a
failure, feedback line
vapor lock
Less Temperature Low ambient - Steam tracing
temperature
More Flow Line fracture Spillage (possible
large explosion)
Pump seal Spillage (possible
failure small explosion)
Control fault Consider bypass
No Flow - Shutdown Low level alarm
Shutdown Automatic startup
of standby pump
Reverse Flow Pump Backpressure -
failure on storage
vessel
As well as Impurities - Possible small Priming line
detonation

21. Produce a fault tree for the following system where the highest-order event is
overpressure of the vessel. The possible causes of various failures should be sug-
gested.

To instrument
air system

22. List all the areas in the sodium dodecylbenzene sulfonate process described in Chap.
2 that could be potential danger areas with respect to the health and safety of