The comparison is both on technical and economical grounds. Modelling of the processes is first performed in Aspen Hysys v8.8, including the selection of an appropriate thermodynamic model. The authors chose the Peng-Robinson-Stryjek-Vera (PRSV), which is especially capable of modelling nonideal fluid behaviour composed of dissimilar components.
Next to compare processes in terms of their environmental impact, the authors wanted to make use of the WAste Reduction (WAR) algorithm to describe the flow and the generation of Potential Environmental Impact (PEI) through a chemical process. The implementation of the WAR algorithm by Bill BARRETT el al. at U.S. Environmental Protection Agency is targeted by the authors.
This implementation of the WAR algorithm is present in the Process Modelling Environement (PME) called COFE from AmsterCHEM. So the authors needed to model the extraction processes in COFE as done previously in Aspen Hysys and then apply the WAR algorithm to these flowsheet models. Since COFE implements a CAPE-OPEN thermodynamic socket, the authors exported the thermodynamic model based on PSRV from Aspen Hysys, plugged it into COFE and were able to reproduce the process models from Aspen Hysys in COFE using the very same thermodynamic model in both PMEs.
This is another example of using the most suitable thermodynamic model in different Process Modelling Environments, thanks to the capability offered by CAPE-OPEN. It is also an example of use of COWAR, the CAPE-OPEN version of the WAR algorithm implemented at U.S. EPA. This implementation relies on an early, non-official, version of the Flowsheet Monitoring interface specification. A new version of that interface specification is under development by the Methods & Tools Special Interest Group.
is the ability to access all elements in a flowsheet without interfering with the flowsheet. Flowsheet Monitoring Components are software components that can be plugged into a flowsheet and have access to all thermodynamic property calculation methods, all Streams and all Unit Operations.
Flowsheet Monitoring Components gain read-only access to flowsheet elements via collection interfaces exposed by a new interface, ICapeFlowsheetMonitoring, implemented by the Simulation Context. The Flowsheet Monitoring Component can be invoked via the methods of its ICapeFlowsheetMonitoringComponent interface, or by means of responding to events. The event handlers are methods on a new interface, ICapeFlowsheetMonitoringEventSink, that are invoked by the PME.