Coupling Effect of Operating Conditions on Performance of SOFC-GT with Anode Exhaust Gas Recirculation

Abstract

This work proposed a study on a hybrid system of solid oxide fuel cell (SOFC) and gas turbine (GT) with anode exhaust gas recirculation. A pre-reformer of methane was suggested to reduce a complete reforming reaction in a SOFC stack. Thus, the pre-reforming percentage as an important parameter was examined, coupling with main operating conditions that include steam to carbon ratio (S/C), SOFC temperature, SOFC pressure, anode recirculation ratio (AR), fuel utilization (U<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">f</inf>). Thermodynamics calculation of this system was carried out by using Aspen Plus simulator. The investigation results revealed that increasing pre-reforming percentage reduce both efficiencies of SOFC and hybrid system. This is in turn that a low level of methane pre-reforming is sufficient to operate in SOFC-GT system with anode exhaust gas recirculation. In addition, the results revealed that the maximum system efficiency of 94.65% can be obtained at 10% pre-reforming, S/C of 2.0, SOFC temperature of 1173 K, SOFC pressure of 7 bar, AR of 0.3 and U<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">f</inf> of 0.9.