Page 124 - Design of Simple and Robust Process Plants

4.2 The Methodology of Process Synthesis 109

Lights
Lights

Water
Feed Reactor Product

Tars/heavies
By-product
Unconverted reactant & Tars

Fig. 4.19. Distillation scheme: 3rd generation.

Lights

C.W.
Lights

By-product Water

Product
Feed Reactor

Tar/heavies
Unconverted reactant

Fig. 4.20. Simplified distillation scheme: 4th generation.

. The third generation flowsheet converts the flowsheet into a two-column con-
cept where the first column is equipped with a dephlegmator (a partial con-
denser with rectification). This flowsheet is a very reduced concept of the con-
ventional flowsheet of five, and it out performs the capital cost and energy
requirements of the original flowsheet. The example illustrates that any form
of sequence selection and energy integration of the original flowsheet is sur-
passed by the simplification effort as applied.