Transient Modeling of the NETL Hybrid Fuel Cell/Gas Turbine Facility and Experimental Validation

Abstract

This paper describes the experimental validation of two different transient models of the hybrid fuel cell/gas turbine facility of the U.S. DOE-NETL at Morgantown. The first part of this work is devoted to the description of the facility, designed to experimentally investigate these plants with real components, except the fuel cell. The behavior of the SOFC is obtained with apt volumes (for the stack and the off-gas burner) and using a combustor to generate similar thermal effects. The second part of this paper shows the facility real-time transient model developed at the U.S. DOE-NETL and the detailed transient modeling activity using the TRANSEO program developed at TPG. The results obtained with both models are successfully compared with the experimental data of two different load step decreases. The more detailed model agrees more closely with the experimental data, which, of course, is more time consuming than the real-time model (the detailed model operates with a calculation over calculated time ratio around 6). Finally, the TPG model has been used to discuss the importance of performance map precision for both compressor and turbine. This is an important analysis to better understand the steady-state difference between the two models

Flexible Micro Gas Turbine Rig for Tests on Advanced Energy Systems

“…This software (Traverso, 2005) is a simulation program based on an easy access library designed for the off-design, transient and dynamic analyses of advanced energy systems based on microturbine technology. 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).…”

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]. The current work seeks to illustrate the fidelity of the hybrid system modeling methodology developed at the National Fuel Cell Research Center [10,18,24,28,29] and draw attention to critical system sensitivities caused by fluctuations in temperature, electrochemical current, and fuel composition variations.…”

“…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].…”

“…Commercialization of advanced hybrid SOFC/GT technology requires considerable improvement of core component (e.g., pressurized SOFC) performance, system integration, and dynamical control [5][6][7]. Mathematical modeling provides cost-effective understanding that combined with demonstration and verification experiments can aid in the continuing development of SOFC/GT technology and control strategy testing [8][9][10].…”

Fuel cell–gas turbine hybrid system design part II: Dynamics and control

“…Early experimental results and demonstration units [3,7] have highlighted the need for additional controls development, particularly for disturbance rejection [8] and off-design operation [9]. Test facilities employing a hardware-in-the-loop approach have been built in the United States [10] and Italy [11] to test various features of transient turbine operation, particularly start-up, shut-down, and the stall/surge phenomena [12]. Researchers in the Thermochemical Power Group have identified several distinct challenges of pressurized SOFC operation in particular the unstable behavior resulting from pressure transients in the cathode and anode compartments [13,14].…”