Multi-objective optimization of biomass gasification based combined heat and power system employing molten carbonate fuel cell and externally fired gas turbine

Bioenergy is expected to play a critical role in a Net-Zero 2050 scenario. India ranks second in the world in terms of rice production. By-product rice husk, which is produced in large quantities, is currently burned and discarded by farmers. The primary objective of the research is to use rice husk as a fuel in an energy system that would otherwise be wasted. The rice husk might be better utilised to produce hydrogen-rich syngas, which could subsequently be used to generate clean electricity in fuel cell-based systems. Here, a novel combined heat and power system consisting of a biomass gasifier, molten carbonate fuel cell (MCFC), an externally fired gas turbine (EFGT), and a water heating facility has been developed. The proposed cogeneration system has undergone extensive thermodynamic and economic analyses. In addition, response surface methodology (RSM) was used for multiobjective optimization. An extensive investigation was conducted to determine how design factors influence exergy efficiency and the levelized unit cost of energy of the system. The results suggest the optimal design parameters are found at current density = 1015.25 A/m2, cell temperature = 700 celcius, and pressure ratio = 1.69. The optimization analysis shows that the cogeneration system has the maximum exergy efficiency of 41.15% and the lowest levelized unit cost of energy of 0.044 $/kWh.