Multi-criteria assessment and optimization of a biomass-based cascade heat integration toward a novel multigeneration process: Application of a MOPSO method

In this study, a novel biomass-driven cascade heat integration scheme is devised, encompassing combined cooling, heating, and power generation, with a unique focus on the production of a secondary product (fresh-water). The process commences with the establishment of a biomass digester, yielding biogas fuel to kickstart the integrated system. Subsequently, the utilization of a gas turbine cycle is introduced, and its waste heat is efficiently harnessed through a supercritical carbon dioxide process, a double-effect refrigeration cycle, and a heating terminal. Additionally, a modified organic Rankine cycle is incorporated to recover heat from the su-percritical carbon dioxide process, while reverse osmosis desalination forms an integral part of the equipment lineup. The entire system is rigorously evaluated from both thermodynamic and economic standpoints, under-going optimization across five distinct scenarios. A multi-objective particle swarm optimization approach, featuring two decision-making algorithms, is deployed in this optimization process. The primary objective is exergetic efficiency, while the secondary objectives encompass net output power, cooling, heating, sum unit cost of products, and net present value, each considered individually. The results of the study reveal that the highest attainable optimal exergy efficiency stands at 38.54 % when the secondary objective is net output power. Furthermore, the optimal values for the secondary objectives are determined to be 41112.59 kW, 1383.75 kW, 28413.97 kW, 18.72 $/GJ, and 75.17 M$, respectively. These findings underscore the potential of the proposed biomass-driven cascade heat integration system in achieving efficient and sustainable energy generation while simultaneously producing valuable secondary products.