Information Technology Reference
In-Depth Information
Figure 9.7
Heatx block primary input form.
exchanger design. The specification used for design, the outlet temperature of the cold
stream, which was used for both exchangers, was transferred from the four-heater
flowsheet to the two-exchanger flowsheet. The
UA
values calculated for the shortcut
design of two exchangers were transferred to the simulation flowsheet to produce
the completed process simulation. Details may be found at Examples by comparing
twoheatxflowsheetd (design) and twoheatxflowsheets (simulation). When using rating
or simulation calculations, both the shortcut and detailed options permit the user to
enter estimates of the overall heat transfer coefficients from sources such as Perry and
Green (1999). In addition to an overall heat transfer coefficient, the heat transfer area
must be provided.
The detailed option permits only rating and simulation modes, both of which can be
used as part of a sequential modular simulation. In both cases the selection of geometry
prompts a user for the detailed layout of a shell-and-tube heat exchanger. A detailed
design must be completed prior to the selection of this option.
As can be seen from the calculation frame in Figure 9.7, Aspen Plus provides a
rich selection of detailed design calculation methods. These are referred to as Aspen
Exchanger Design and Rating. An example of the use of “shell and tube” is given by
redesigning the first exchanger at Examples/twoheatxflowsheetd. The input is virtually
identical to that at Examples/twoheatxflowsheetd except for the identification of the
hot fluid and the specification of an input file, as shown in Figure 9.9. This example
is given at Examples/B3shellandtube. The file B3shellandtube.txt gives a report of the
