Modeling and multi-objective optimization of a novel biomass feed polygeneration system integrated with multi effect desalination unit

This paper mainly focuses on the design and optimization of a novel integrated system to meet fresh water, electricity, and hot water demands. A novel combination of different system is used to generate multi products. The exergy and economic analyses are combined to carry out a parametric study to find the impact of main decision variables on a polygeneration system. The exergy analysis reveals that combustion chamber and gasifier have the highest exergy destruction rates with 84% of the system total exergy destruction rate. In addition, the system exergy efficiency shows that in the initial state, the exergy efficiency of polygeneration system is 27.9%. Results show that an increment in the gasification temperature from 950 K to 1150 K leads to fresh water flow rate increases from 1060m(3)/day to 1160m(3)/day. The parametric study of the system reveals that the defined objective functions are highly depends on the changes in the nine decision variables. Using a genetic algorithm optimization method, the optimum design values are obtained. The results of multi-objective optimization show that within reasonable changes for decision variables, the system exergy efficiency can change between 20% and to 42%, and the system total cost rate can vary from 100 $/h to 600 $/h.