Background. Thermal and nuclear power plants widely use thermal methods of water treatment that have a number of environmental and economic advantages. Thermal methods are often implemented in evaporation units, which allow obtaining pure distillate using low-potential heat. Thus, implementation of these units is a promising trend for water treatment at thermal and nuclear power plants. It should be noted that liquid droplet carryover in evaporation units significantly affects the quality of the distillate. Molecular steam contains virtually no impurities, but with an increase of the intensity of energy supply and active vaporization, liquid droplets can be entrained into the vapor phase. It leads to contamination of the finished product. To select effective operating modes and design parameters of the evaporation unit, the development of a mathematical model of heat and mass transfer considering liquid droplet entrainment is of particular relevance.
Materials and methods. To solve problems of modeling heat and mass transfer processes in multi-stage evaporation units, the authors have used the models that are based on mass and energy balance equations, presented in matrix form.
Results. A matrix model of a multi-stage evaporation unit is proposed, considering the droplet entrainment of liquid during evaporation and the corresponding contamination of the finished product with impurities.
Conclusions. The developed model of the heat and mass transfer process allows us to solve direct and inverse problems on the efficient organization of heat and mass transfer processes in units for various purposes. In turn, it serves as a basis to set and solve problems on the selection of optimal design and operating parameters of evaporation units. The proposed method to solve the problem of heat and mass transfer modeling provides the possibility of simultaneously searching for acceptable values of the design and operating parameters of multi-stage evaporation units for various purposes.