A computer aided system for correlation and prediction of phase equilibrium data

Modelling, simulation and design of chemical processes need accurate and re liable estimation of the properties of the mixtures present in the process. In these situations, the property models are in a 'service' role where the y supply the needed properties only when requested. Due to the solution pro cedures employed in simulation and design, the property models are required to have well-behaved and continuous derivatives for these problems to conv erge a solution. Furthermore, in process optimisation, the second and third order derivatives of the property models must exist for solution approache s based on mathematical programming. This paper describes the development o f a computer aided system for the systematic derivation of appropriate prop erty models to be used in the service role for a specified problem. As a fi rst step, a library of well-known property models ha's been developed and a feature for parameter estimation has been added, so that for any selected model, the necessary model parameters can be estimated, fine-tuned and/or c onverted from one model to another model. Also, the property derivatives ar e validated and verified for thermodynamic and mathematical consistency. (C ) 2001 Elsevier Science B.V. All rights reserved.