Exporting To Aspen Dynamics

Aspen Dynamics uses the steady-state information generated in Aspen Plus, but they are two different programs with different files. The Aspen Plus file is filename.apw, and there is also a backup file, filename.bkp, that is generated. The latter file can be used to upgrade to newer versions of Aspen Plus.

The information from Aspen Plus is "exported" into Aspen Dynamics by generating two additional files. The first is a filename.dynf file that is used in Aspen Dynamics and is modified to incorporate controllers, plots, and other features. The second file is a

Aspen Plus
Figure 7.3 Specifying diameter and weir height.
Figure 7.4 Pressure check.

filenamedyn.appdf file that contains all the physical property information to be used in Aspen Dynamics.

In the propane/isobutane column example, the Aspen Plus files are called Example1.apw and Example1.bkp. The files generated and used in Aspen Dynamics are Example1.dynf and Example1dyn.appdf.

The procedure for "exporting" is to click on File at the top left corner of the Aspen Plus window and select Export. The window shown in Figure 7.5 opens, and the dropdown menu is used to select P driven Dyn Simulation, which is the tenth item on the list. Then the Save button is clicked.

An error appears (Fig. 7.6a), which informs us that the specified pressure drop (0.0068 atm) is too small for the given weir height and vapor rates. Aspen Dynamics calculates tray pressure drops rigorously, and they change with vapor and liquid rates. We have two options: increase the specified pressure drop or decrease the weir height. The latter has no effect on the steady-state solution, so we go back to Dynamics under the C1 block, select the Hydraulics page tab, and change the weir height from 0.05 to 0.025 m. Running the program again, pressure checking, and "Exporting" again cause the

Figure 7.5 Exporting.

Fatal Error Messages Exporting Dynamic Simulation

TRANSLATE USING COMPILED AST PROCEDURES IN C:\Program Files\AspenTech\Aspen Dynamics 12.1 \Ast DIRECTORY.

TRANSLATING BLOCK C1 of TYPE RADFRAC:

The specified pressure drops in the column are smallerthan the liquid head on the stages listed below. Please adjust the pressure profile on the Pressure sheet of the Setup form. Atypical total pressure drop across a stage is tovice the pressure drop due to liquid head. Alternatively, modify the weir heights or column diameter on these stages. If you are modelling a packed column, select the Simple Packing option on the Hydraulics sheet of the Dynamics form. If you are using tra^rating or packing-rating, ensure your input parameters are consistent.

P_dropL = Pressure drop due to liquid head on stage (Bar).

Warning Messages Exporting Dynamic Simulation

TRANSLATE USING COMPILED AST PROCEDURES IN C:\Program Files\AspenTech\Aspen Dynamics 12.1 \Ast DIRECTORY.

TRANSLATING BLOCK C1 of TYPE RADFRAC:

WARNING: There is no valve immediately downstream of the liquid distilate stream. A reflux drum level controller will not be added automatically as its output can not be connected. You should check whether a level controller is needed for a stable dynamic simulation.

WARNING: There is no valve immediately downstream of the bottoms stream. A sump level controller will not be added automatically as its output can not be connected. You should check whether a sump level controller is needed for a stable dynamic simulation.

TRANSLATING BLOCK P11 of TYPE PUMP:

Default performance and efficiency curves will be used. See the Help Topic Pump in Dynamic Simulations for details.

TRANSLATING BLOCK P12 of TYPE PUMP:

Default performance and efficiency cutves will be used. See the Help Topic Pump in Dynamic Simulations for details.

Figure 7.6 (a) Error message; (b) warning message.

window shown in Figure 7.6b to open. These messages just remind us that level controllers should be installed once we get into Aspen Dynamics and the typical pump curves are used in the pumps.

The "export" is successful, and we are ready to go into Aspen Dynamics.

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  • Maik
    How to export files from aspen plus to aspen dynamics?
    8 years ago

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