Understand Thermodynamics to Improve Process Simulations

摘要

When using a chemical process simulator, the most important decision affecting the quality of results is selection of a thermodynamic model. New and experienced engineers alike often find this task challenging. Many do not realize how important this decision is, how to make it, or how to validate the decision. This article provides a basic overview of how to select and validate a vapor-liquid equilibrium model for process simulation. Process simulation software calculates heat and material balances. This requires determining the separation of a chemical mixture between the liquid and vapor phases. While many different thermodynamic models are available, using the wrong model, or estimating a physical property incorrectly, can lead to inaccurate results for the overall simulation.