Information Technology Reference
In-Depth Information
Figure 7.3
Flash2 example specifications.
Figure 7.4
Flash2 example results.
parameters were obtained from the data source apv70vle-lit. The upper and lower tem-
peratures of applicability are also shown. If this set is deemed inappropriate, selection
of the tab Databanks permits the user to select an alternative source of data. The input
specifications for this example are shown in Figure 7.3, and the flash results are given
in Figure 7.4.
A useful feature of the Flash2 and some other equilibrium stage blocks is the ability
to specify entrainment; that is, a specified fraction of the liquid phase is carried by
the flashing vapor into the overhead. A comparison of the performance of a Flash2
block with and without entrainment is given at Examples/Flash2EntrainmentExample.
The flowsheet is shown in Figure 7.5. A comparison of the overheads produced by
the flash is given in Figure 7.6. The composition of stream 22 is lower in the more
volatile component, methanol, and its fraction vapor is less than 1.0.
7.2 Flash3 BLOCK
Figure 7.7 is a graphical depiction of a Flash3 block. The nomenclature used is as
follows:
F
represents the total feed flow, in moles/time;
f
i
the flow of component
i
in the feed, in moles/time;
V
the total vapor flow, in moles/time;
v
i
the flow of
component
i
in the vapor, in moles/time;
L
1
the total flow of the first liquid phase, in
moles/time;
I
i
, the flow of component
i
in the liquid, in moles/time;
L
2
the total flow
