Design, modelling and techno-economic analysis of a solid oxide fuel cell-gas turbine system with CO₂ capture fueled by gases from steel industry

The steel industry is one of the major sources of CO₂ emissions that are released in the manufacture and process of steel as well as in related power production. Focused on reduction of CO₂ emissions in the power production, this paper presents a novel solid oxide fuel cell-gas turbine combined heat and power system fed by coke oven gas. The solid oxide fuel cell-gas turbine system design consists of an adequate gas cleaning section for contaminants removal, solid oxide fuel cell as the main power producer and an anode offgas pressure swing adsorption based CO₂ capture unit. This system is thermodynamically and techno-economically analyzed and compared with a reheat steam turbine. Furthermore, the reheat steam turbine is retrofitted with a CO₂ capture unit. It is then compared to the solid oxide fuel cell-gas turbine system to analyse the difference in system efficiencies. The solid oxide fuel cell-gas turbine system yields an electrical efficiency of 64%, which is significantly higher than electrical efficiency achieved by both, a conventional reheat steam cycle (34.1%) and the retrofitted system (27.0%). Moreover, it depicts a combined heat and power efficiency of 73%. Results also reveal that the solid oxide fuel cell-gas turbine system can achieve a reduction of 50% in CO₂ emissions for equal power production. Furthermore, techno-economic analysis lead to a payback period of 9 years, taking into account state-of-the-art taxes and variation in the cost of components over the lifetime, without taking into account the fuel cost.