Abstract
Today, optimisation of Fluid Process Engineering is largely associated with process intensification, which results in rising process complexity and higher requested accuracy of process description. This is often beyond the capabilities of conventional modelling methods. A new concept called complementary modelling has recently been suggested, which uses different modelling approaches in combination, while their rigor and complexity stretch over a wide range. Among these approaches are a direct application of the equations of fluid dynamics, the hydrodynamic analogy method and the rate-based approach. In this contribution, the complementary modelling is highlighted and illustrated with a case study related to CO2 capture.