A new modular procedure for industrial plant simulations and its reliable implementation

Modeling of industrial plants, and especially energy systems, has become increasingly important in industrial engineering and the need for accurate information on their behavior has grown along with the complexity of the industrial processes. Consequently, accurate and flexible simulation tools became essential yielding the development of modular codes. The aim of this work is to propose a new modular mathematical modeling for industrial plant simulation and its reliable numerical implementation. Regardless of their layout, a large class of plant's configurations is modeled by a library of elementary parts; then the physical properties and the compositions of the working fluid, and the plant's performance, are estimated. Each plant component is represented by equations related to fundamental mechanical and thermodynamic laws giving rise to a system of algebraic nonlinear equations; moreover, suitable restrictions on the variables are imposed to guarantee solutions with physically meaning. The proposed numerical procedure combines an outer iterative process which refines plant’s characteristic parameters and an inner one for solving the arising nonlinear systems. These are solved by a trust-region solver for bound-constrained nonlinear equalities. The good computational speed and robustness of the proposed modular procedure is reported on two compression train arrangements with series and parallel-mounted compressors.