Custom Evaluation of Dielectric Constant Using User Properties and Subroutines in Aspen Plus
Project Description
Retrieving dielectric constant values in Aspen Plus requires a customized approach, as this property is not available as a standard output. By leveraging the temperature-dependent CPDIEC parameter within the ELECNRTL property method, and implementing user-defined subroutines via dynamic link libraries (DLLs), both pure component and mixture dielectric constants can be accurately evaluated. The methodology involves configuring user properties (UPDIPU for pure components, UPDIMX for mixtures), defining property sets, and linking the appropriate DLL through the Aspen interface—without requiring a Fortran compiler. This solution enables enhanced thermodynamic modeling for systems where dielectric properties significantly influence phase behavior, solvation, and electrolyte interactions, providing valuable insights for process design and optimization.
Custom Dielectric Property Integration in Aspen Plus
Dielectric constants were incorporated into Aspen Plus using user-defined properties supported by a dynamic link library (DLL). As shown in the figure, the method employs CPDIEC parameters and custom subroutines—labeled UP-1 for mixtures and UP-2 for pure components—which are inserted into Aspen through linker options (e.g., “props.dlopt”).
Project Insights
CPDIEC Parameter Utilization
• Aspen Plus lacks built-in reporting for dielectric constant as a direct property.
• CPDIEC parameter provides temperature-based estimates for pure component permittivity.
Compatibility with ELECNRTL Model
• ELECNRTL model must be enabled to use CPDIEC for dielectric property evaluation.
• Ensures accurate interpretation of electrolyte systems and dielectric behavior.
User-Defined DLL Integration
• UP-1 and UP-2 properties use UPDIMX and UPDIPU subroutines to compute mixture and pure component permittivity.
• A dynamic link library (.dll) runs these subroutines efficiently without the need for compilation.
Property Set Integration and Reporting
• User-defined properties are incorporated into a property set for inclusion in simulation stream reports.
• This allows enhanced electrochemical analysis and visualization of dielectric behavior across process streams.
Conclusion
This project demonstrates a systematic approach to estimating dielectric constants in Aspen Plus by integrating custom user-defined properties and dynamic link libraries (DLLs). By leveraging the CPDIEC parameter within the ELECNRTL thermodynamic model and embedding UPDIMX and UPDIPU subroutines via DLL, users can retrieve both mixture and pure component dielectric constants with flexibility and efficiency. This approach extends Aspen Plus capabilities beyond standard property estimation, providing a valuable method for electrochemical and electrolyte system modeling.