Page 170 - Design of Simple and Robust Process Plants
P. 170
5.3 Combination of Process Functions 155
Petlyuk column
COOLING
PRODUCT A
PREFRACTIONATOR
MAIN COLUMN
FEED
PRODUCT B
STEAM
PRODUCT C
Fig. 5.6. The Petlyuk column, heat integrated with multiple products.
Divided wall column Two column separation
COOLING
COOLING
COOLING
PRODUCT A
PRODUCT B
FEED
FEED
PRODUCT B PRODUCT A
STEAM
STEAM
STEAM
PRODUCT C
PRODUCT C
Fig. 5.7. Divided wall column versus conventional two column separation.
uration, which was anticipated as one of the major difficulties, can today easily be
designed based on dynamic simulations. Mechanical design problems have been
solved, and the uncertainties of control and mechanistics have now been removed.
The result has been a major increase in the number of applications ± at the time
mainly at BASF where the concept was first conceived.
The divided wall columns can realize energy and capital savings of up to 30%
compared with a nonintegrated, two-column separation. Moreover, the column can
potentially also be applied to four-product separations, though restrictions to such
application include:
