Analysis and multi-objective optimization of integrating a syngas-fed solid oxide fuel cell improved by a two-stage expander-organic flash cycle using an ejector and a desalination cycle

New biomass-based high-temperature fuel cell technologies flexibly integrate biomass processing, high-quality electricity generation, and waste heat recovery. Hence, the current paper deals with a modified waste heat re-covery framework for a biomass gasifier plus solid oxide fuel cell technology. For this purpose, an ejector-based two-stage expander-organic flash cycle and a humidification dehumidification desalination unit are integrated into the upstream cycle resulting in excess electricity and freshwater generation. With about eight crucial pa-rameters limiting the entire operation, a comprehensive thermodynamic- exergoeconomic-and exergoenvironmental-based sensitivity study is accomplished. In addition, considering the exergy efficiency as the most significant objective function, three different double-objective optimization scenarios are conducted utilizing a multi-objective particle swarm optimization. Herein, freshwater generation rate, products' cost rate, and environmental impact are involved in underlined scenarios as the second objective function. Among limiting parameters, performance metrics change substantially by the fuel cell's temperature difference and the air compressor's pressure ratio. According to the optimization, the most appropriate exergy efficiency was found at 40.05%, attributable to the exergy efficiency/environmental impact rate scenario. The optimum freshwater generation rate, products' optimum cost rate, and environmental impact rate are computed to be 0.074 kg/s, 6.18 $/day, and 0.15 mPts/s, respectively.