Thermoeconomic analysis and multi-objective optimization of a solid-oxide fuel cell plant coupled with methane tri-reforming: Effects of thermochemical recuperation

An 80-kW solid-oxide fuel cell (SOFC)-based power plant coupled with methane tri-reforming is proposed and analyzed from the viewpoint of thermoeconomics. In order to integrate the SOFC power generation section with the external reformer, part of the exhaust gases from the afterburner is recycled and utilized as a reformer agent in the reactor. The main challenge in performing the economic analysis is the determination of the costs associated with the tri-reforming process, in particular the reactor cost. To accomplish this, a mathematical procedure is suggested and applied for a fixed-bed reactor based on both the chemical equilibrium and chemical kinetics describing the tri-reforming process. The effects on system performance of important design parameters, including current density, SOFC operating temperature, and exhaust gas recirculation (EGR) percentage, are investigated. The results indicate that system performance is enhanced by using lower values of current density and higher values of SOFC operating temperature. In addition, considering the thermal and environmental performance of system as criteria, the use of EGR is not recommended. However, as the EGR percentage increases, the product unit cost decreases, making EGR advantageous from an economic perspective.