Re-Compression Model for SOFC Hybrid Systems: Start-up and Shutdown Test for an Emulator Rig

This paper reports a new innovative re-compression technology for solid oxide fuel cell (SOFC) hybrid systems necessary to increase pressure at compressor outlet level (as required by fuel cell systems for managing cathodic recurculation and to increase SOFC efficiency). This work was based on a collaboration between the University of Manchester (United Kingdom) and the University of Genoa (Italy). The re-compression study will be performed with the hybrid system emulator rig by TPG. This device is composed of the following technology: a microturbine package able to produce up to 100 kWe which was modified for external connections, external pipes designed for several purposes (by-pass, measurement or bleed), and a high temperature modular vessel necessary to emulate the dimension of an SOFC stack. For the purpose of re-compression, this test rig is planned to be equipped with a turbocharger capable of increasing pressure using part of recuperator outlet flow. Theoretical activity was considered before carrying out the real experimental tests to avoid plant risky conditions. So, it was necessary to develop a transient model (Matlab-Simulink environment) to simulate the hybrid system emulator including the re-compression system. The results obtained with the model were carried out considering the start-up/shutdown phases of the turbocharger device.