Potential of biomass processing using digester in arrangement with a Brayton cycle, a Kalina cycle, and a multi-effect desalination; thermodynamic/environmental/financial study and MOPSO-based optimization

Abstract

This works aims at proposing, analyzing, and optimizing a biomass-based tri-generation system for electricity, heating, and freshwater production. A Brayton cycle is configured so that its output stream conveys to the pre-combustion chamber reacting with biogas generated by the biomass digester. This integration exhibits an opportunity to combine a Kalina cycle, a multi-effect desalination, and a heating unit with the top system. Multi-objective particle swarm optimization is employed to obtain the optimal working conditions of the system in different optimization scenarios. The investigation results reveal that the compressor inlet pressure variation mainly impacts the metric performance indicator. For the mass flow rate of 15 gr/s of methane at the base condition, the biomass flow rate is obtained 13.23 kg/s, and the exergetic efficiency is evaluated to be 42.53%. Also, at the optimum operation mode of the first scenario, the exergetic efficiency and heating output are obtained at 45.51% and 531.41 kW, respectively. Moreover, the second scenario that employs exergetic efficiency and levelized total emission as objectives leads to values of 45.69% and 69.17 ton/kW for the objectives, respectively. Besides, the first scenario possesses the highest profitability with a payback period of 5.05 years.