Modelling the properties of liquid foods for use of process flowsheeting simulators: Application to milk concentration

In this paper, a modelling approach for liquid food products in a chemical process simulator is proposed from the flowsheeting methodology widely used for chemical processes. The focus is set on dairy concentration processes, in which milk is defined as a mixture of water and four dry matter components (fat, proteins, carbohydrates, minerals) modelled as “pseudo-components” in a conventional simulator which has been adapted to take into account the behaviour of the liquid food product considered. The significant properties of milk (heat capacity, boiling point elevation, thermal conductivity, density, viscosity, surface tension) are modelled with empirical models found in the literature and implemented in the simulator. In order to validate the approach, an industrial milk evaporation process and a pilot-scale evaporator are modelled and simulated. The results are compared with industrial and experimental results respectively, and show a good agreement with the industrial process. However improvements are needed in modelling the pilot scale evaporator. The proposed approach is generic enough to be extended to other liquid foods.