During the last decade, a major shift has begun in chemical industry, since there is an urgent need for new tools that are able to support the optimization of operating technologies. This trend is driven by the new tools of information technology. Approaches of this shift differ from company to company but one common feature is that communication between design, manufacturing, marketing and management is centered on modeling and simulation, which integrates not only the whole product and process development chains, but all the process units, plants, and subdivisions of the company. These approaches are under continuous development. Among the wide range of possible improvements, this paper focuses to two frequent imperfections: (i) developed and refined process models are used only in advanced process control system (APC) integrated into distributed control system (DCS) and operator training systems (OTS), and not for detailed analysis and optimization, and (ii) optimal process operating points of these chemical plants are adjusted only at the design and test phase of a new technology, but optima moves with time, new catalyst system, lower price of reactants, claim for new or higher purity products, etc. The aim of this paper is to review, how to manage process optimization, and to show our process simulator based on the chemical engineering model of the technology. This paper will present a case study to demonstrate the technological and ecological benefits of the analysis and optimization of an operating multi-product polymerization plant. The models of advanced process control system (APC) and reactor cascade were implemented in MATLAB® Simulink® environment, as a powerful and popular dynamic simulator.