(596a) Consuming CAPE-OPEN Thermodynamics From Multi-Threaded Applications

Process design often starts with flowsheet based steady state process models to assess initial process cost and feasibility. In addition to process design, steady state process models are also used for optimizing process performance. Dynamic flowsheet models find applications in process control, monitoring and operator training. All of these applications are largely driven by thermodynamic calculations that typically make up a large part of the computational cost.

Such simulations are often performed in simulation applications of a particular vendor, that have thermodynamic sub-models and unit operation sub-models all combined in a single application. For many applications, thermodynamic models built into these simulation applications, is not sufficient, and external third party thermodynamic servers are employed. For third party thermodynamic vendors, CAPE-OPEN is an attractive way of interfacing with flowsheet simulation applications; CAPE-OPEN is an open set of standards for exchange of chemical process engineering sub-models such as thermodynamics and unit operations between process simulation applications.

Traditionally, flowsheet simulations have been performed in single-threaded applications. With emerging computer power and hyper threading and multi-core modern-day computers, simulation time can be brought down significantly by employing multi-threaded or multi-core simulations.

Performance of thermodynamic sub-systems however is paramount, due to its large contribution to overall computational time. Nearly all CAPE-OPEN thermodynamic server applications that currently exist are based on apartment threaded COM implementations. Naively using such packages in a multi-threaded environment will invoke COM-marshalling of thermodynamic calculation calls between the simulation environment and the thermodynamic server, thereby significantly reducing computational performance.

This presentation will share the experiences applying multi-threaded calculations employing CAPE-OPEN based thermodynamic server software; it presents a simple framework for accessing thermodynamics from multiple threads within the same application, without invoking marshalling of thermodynamic calculations. Such calculations have been implemented in COCO version 2, which is available free-of-charge from http://www.cocosimulator.org/.