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. The need for accurate information on the behavior of such systems has grown along with the complexity of the industrial processes that are getting close to their limits (with respect to the process, materials, missions or economics). As a consequence, accurate and flexible simulation tools have become essential and led to the development of modular codes. The purpose of this work is to propose a new modular mathematical modeling for industrial plant simulation and its numerical implementation via a modular procedure. 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, as well as plant’s performance, are estimated. Each plant component is represented by equations related to fundamental mechanical and thermodynamic laws. The system is therefore described by a system of algebraic equations that are nonlinear in most cases. In order to obtain a solution of physical meaning, suitable restrictions on the variables are imposed. The numerical procedure proposed in this work combines an outer iterative process which refines characteristic parameters of the plant and an inner iterative procedure for solving the nonlinear systems resulting from the outer iteration. The solution of such systems is performed through a trust-region solver for bound-constrained nonlinear equalities. The performance of the proposed modular procedure is reported on two compression train arrangements with both series and parallel-mounted compressors; the obtained results shows good computational speed and robustness of the code.