Hybrid Simulation Facility Based on Commercial 100 kWe Micro Gas Turbine

Abstract

A new high temperature fuel cell-micro gas turbine physical emulator has been designed and installed in the framework of the European Integrated Project “FELICITAS” at the Thermochemical Power Group (TPG) laboratory located at Savona. The test rig is based on a commercial 100 kWe recuperated micro gas turbine (mGT) (Turbec T100) modified to be connected to a modular volume designed for physical emulation of fuel cell stack influence. The test rig has been developed starting with a complete theoretical analysis of the micro gas turbine design and off-design performance and with the definition of the more flexible layout to be used for different hybrid system (molten carbonate fuel cell or solid oxide fuel cell) emulation. The layout of the system (connecting pipes, valves, and instrumentation, in particular mass flow meter locations) has been carefully designed, and is presented in detail in this paper. Particular attention has been focused on the viscous pressure loss minimization: (i) to reduce the unbalance between compressor and expander, (ii) to maintain a high measurement precision, and (iii) to have an effective plant flexibility. Moreover, the volume used to emulate the cell stack has been designed to be strongly modular (different from a similar system developed by U.S. Department Of Energy-National Energy Technology Laboratory) to allow different volume size influence on the mGT rig to be easily tested. The modular high temperature volume has been designed using a computational fluid dynamics (CFD) commercial tool (FLUENT). The CFD analysis was used (i) to reach a high level of uniformity in the flow distribution inside the volume, (ii) to have a velocity field (m/s) similar to the one existing inside the emulated cell stack, and (iii) to minimize (as possible) the pressure losses. The volume insulation will also allow to consider a strong thermal capacity effect during the tests. This paper reports the experimental results of several tests carried out on the rig (using the mGT at electrical stand-alone conditions with the machine control system operating at constant rotational speed) at different load values and at both steady-state and transient conditions

Flexible Micro Gas Turbine Rig for Tests on Advanced Energy Systems

“…As an example, this chapter shows the comparison between experimental data and model results related to recuperator outlet temperature (cold side), during a cold start-up phase. Besides the additional developments and tests on the rig, already planned and presented in (Pascenti et al, 2007;Ferrari et al, 2009a;Ferrari et al, 2010c;Prando et al, 2010), all the different layout configurations will be considered for tests. For instance, in an ongoing work it is planned to use the real-time model for control system development activities related on SOFC hybrid plants and the absorber cooler to carry out tests at lower ambient temperature conditions, also considering tri-generative configurations.…”

“…TRANSEO was developed and validated at the University of Genoa in previous studies carried out by both Ph.D. students and TPG researchers (Caratozzolo et al, 2010;Ferrari et al, 2007;Traverso et al, 2005). After an experimental validation in design conditions (Ferrari et al, 2009a), the model was used to calculate the operative curves (at constant TOT) on the compressor map ( To have a wide operative range, as required during the tests, a pressure drop limit of 300 mbar was calculated (the curve at p/p c = 0.069 has a p = 290 mbar at 70000 rpm). These results were necessary to design pipes and valves with wide operative ranges during the tests and manage the rig under safe conditions.…”

Stall/surge dynamics of a multi-stage air compressor in response to a load transient of a hybrid solid oxide fuel cell-gas turbine system

“…In that study, the compressor bleed air was used to avoid the compressor surge during the hybrid system startup. Ferrari et al designed and installed an SOFC-GT physical emulator in the framework of a European Integrated Project [24]. The focus of their study was to minimize the viscous pressure loss in order to: 1) Reduce the unbalance between the compressor and the expander, 2) Maintain an accurate measurement, and 3) Have an effective plant efficiency.…”

Experimental and theoretical evidence for control requirements in solid oxide fuel cell gas turbine hybrid systems

“…Similar SOFC technology development programs have been rapidly advancing SOFC technology in Europe and Japan [22,23]. At the system design level both prototypes and mathematical modeling have developed multiple system designs and control strategies [8,19,[24][25][26][27].…”

“…Some feedback can be beneficial and improve stability; other feedback requires constant control action to maintain operating limits. Because of these complexities, significant previous and ongoing research has developed and applied dynamic modeling to SOFC/GT technology to analyze system behavior, transient performance, and load following capability [2,5,6,8,9,22,25,26].…”