The focus of this paper is the development of fast solvable dynamic mathematical models (real-time models). Real-time models represent a part of model-based tools that can be used to prevent and eliminate emergency situations in industry. In this paper, the development of real-time models is illustrated for chemical absorption, using rigorous dynamic rate-based models. An approach to develop the real-time models is explained in detail and the outcome is presented in the form of mathematical equation systems. The results are shown for the chemical absorption of CO2 by aqueous monoethanolamine solutions.