Process Flow Model of Combined High Temperature Fuel Cell Operated With Mixture of Methane and Carbon Dioxide

This paper investigates the impacts of carbon dioxide concentration in the inlet fuel on the performance of a hybrid tubular solid oxide fuel cell (SOFC) and gas turbine (GT) cycle with two configurations: system with and without anode exhaust recirculation. The reference case is introduced when the system is fueled by pure methane. Then, the performance of the hybrid SOFC-GT system is investigated when methane is partially replaced by CO₂ from concentration of 0% to 90% with an increment of 5% at each step. The steady-state macro level model of the SOFC-GT hybrid system was developed in Aspen Plus^® using built in and user-defined modules. The performance of the system was monitored by estimating and recording performance parameters, such as SOFC and system thermal efficiency; net and specific work of SOFC, GT, and cycle as a whole; air to fuel ratio; and mass and molar flow rate and temperature of various streams. The results demonstrate that the CO₂ fraction in the inlet fuel has remarkable influences on the system’s operating parameters, such as efficiency and specific work.