Exergoeconomic analysis of a combined cycle system utilizing associated gases from steel production process based on structural theory of thermoeconomics

► Improvement directions are given according to three exergoeconomic indexes of each component. ► Influences of decision variables on unitary exergetic and monetary costs of production are investigated. ► Influences of fuel cost on unitary monetary costs of production are far beyond that of purchase cost. ► The superiorities of the proposed system emerge gradually through comparing with other systems.