Coupling impacts of SOFC operating temperature and fuel utilization on system net efficiency in natural gas hybrid SOFC/GT system. (March 2022)

• Record Type: Journal Article
• Authors: Huang, Shanglong; Yang, Chen; Chen, Hao; Zhou, Nana; Tucker, David
• Is Part Of: Case studies in thermal engineering. Volume 31(2022)
• Publication Date: 2022-03
• Subjects: Solid oxide fuel cell -- Gas turbine -- Hybrid system -- Operating temperature -- Fuel utilization -- System performance analysis; Heat engineering -- Case studies -- Periodicals; 621.40205
• DOI: 10.1016/j.csite.2022.101868
• Languages: English
• ISSNs: 2214-157X

Abstract

Abstract: The major design parameters of SOFC have great impacts on the net electrical efficiency of SOFC/GT hybrid systems. The influence of the SOFC operating temperature and fuel utilization on the net efficiency of a pressurized solid oxide fuel cell gas turbine hybrid system was studied in this paper. The system model was combined a 1D SOFC model, which included a lumped equilibrium steam methane reformer model in the Simulink, with a gas turbine recuperated cycle model in Ebsilon®. A system design point study was established to observe the coupling impacts of SOFC operating temperature and fuel utilization on the system performance. Thirty design cases of SOFC operating temperatures (635 °C–835 °C) over a range of SOFC fuel utilization(45%–90%) were evaluated. The optimal SOFC fuel utilization shifted from 65% to 55% when the SOFC operating temperature decreased from 835 °C to 635 °C. The maximal(minimal) system efficiency was 74%(49%) at 65%(90%) SOFC fuel utilization with operating SOFC at 835 °C(635 °C). The results show that high operating temperature leads to the high efficiency of the entire hybrid system, but high fuel utilization might cause a decrease in system efficiency. Highlights: System study of a 100 kW natural gas SOFC-GT hybrid was conducted at high fuel pre-reforming rate. 30 design cases with different SOFC fuel utilization ( U f ) and operating temperature were evaluated. Higher SOFC U f was not related to the higher efficiency of the entire hybrid system. Peak system efficiencies were found at SOFC U f around 55%–65% at all SOFC operating temperatures.