Modular simulation and thermoeconomic analysis of a multi-effect distillation desalination plant

A model for the thermodynamic and thermoeconomic simulation of a MED desalination plant has been developed. As the code is embedded in a modular simulator, CAMEL©, it is relatively easy to use it for analyses of different plant configurations. CAMEL itself had been developed by the Mechanical and Aeronautical Engineering department of the University of Roma 1, “La Sapienza”. In the course of the present project, a model for the MED stage was included in the code library: this allows for a stage level description of the MED plant and for a more correct detailed identification of the plant losses and inefficiencies. The model can simulate all different MED configurations: here, only the parallel flow case was investigated. The thermodynamic model of each component is based on mass and energy balance criteria, and the results have been judiciously compared with literature data. Particular attention was devoted to the development of the thermoeconomic MED stage model: due to the presence of multiple products, the cost allocation is not trivial, and its degree of arbitrariness is even more dependant on the Designer's choices than it is usually in thermoeconomic analysis. A model for cost allocation across product and by-products has been proposed. The model allows individuating different strategies for plant design and optimization. Applications of the model are exposed referring to a possible plant solution and design constrains.