Design and tri-criteria optimization of an MCFC based energy system with hydrogen production and injection: An effort to minimize the carbon emission

The threat of rapid depletion of fossil fuel reserves and the discharge of pollutants due to the depletion of these resources has had catastrophic consequences for the ecosystem. Using efficient energy systems, waste heat recovery from these systems, and decreased carbon dioxide emission cycles is one approach to averting this looming threat in this context. It is proposed in this paper to utilize the electricity generated by the bottoming absorption power cycle to create hydrogen for use in a molten carbonate fuel cell-based energy system. The system is called near-zero carbon since the efficient waste heat utilization allows maximum hydrogen and minimum hydrocarbon fuel use. The concept of the near-zero carbon cycle is being explored from the viewpoints of technology, economics, and the environment. It is necessary to do multi-criteria optimization to establish the optimum operating point of the system under consideration to reduce costs and CO2 emissions while simultaneously increasing efficiency. A parametric analysis is performed to discover the important design parameters that impact the system's performance under consideration. Included among the factors under investigation are the fuel utilization factor (Uf), current density (J), stack temperature (Tstack), and the steam to carbon ratio (rsc). Upon investigation, it was discovered that the suggested system had an energy and exergy efficiency of around 66.21% and 59.5%, respectively. According to the findings of the exergy analysis, the MCFC and afterburner ranked highest in terms of exergy destruction (93.12 MW and 22.4 MW, respectively). The tri-objective optimization findings also reveal that the most optimal solution point has an exergy efficiency of 59.5%, a total cost rate of 11.7 ($/GJ), and CO2 emission of 0.58 ton/MWh.