Comparison Between Conventional Design and Cathode Gas Recirculation Design of a Direct-Syngas Solid Oxide Fuel Cell–Gas Turbine Hybrid Systems Part I: Design Performance

Abstract

ABSTRACT. In this paper, a conventional SOFC-GT hybrid system and an SOFC-GT hybrid system with cathode gas recirculation system fuelled with syngas as the main source of energy were analyzed and their performances were compared. In the conventional SOFC-GT hybrid system the incoming air to the cathode is heated at the air recuperator and air preheater to meet the required cathode inlet temperature while in the SOFC-GT hybrid system with cathode gas recirculation, in addition to the air recuperator and air preheater, also the recirculation of the cathode exhaust gas is used to meet the required cathode inlet temperature. The system performances have been analyzed by means of models developed with the computer program Cycle-Tempo. A complete model of the SOFC-GT hybrid system with these two configurations evaluated in terms of energy and exergy efficiencies and their performance characteristics were compared. Simulation results show that the electrical energy and exergy efficiencies achieved in the cathode gas recirculation plant (64.76% and 66.28%, respectively) are significantly higher than those obtained in the conventional plant (54.53% and 55.8%).Keywords: Solid oxide fuel cell, Gas turbine, Cathode gas recirculation, Exergy.

A Regenerative Coking and Sulfur Resistant Composite Anode with Cu Exsolution for Intermediate Temperature Solid Oxide Fuel Cells

“…H 2 (g) + 2O 2− → 2H 2 O (g) [1] C O (g) + H 2 O (g) ↔ C O 2 (g) + H 2 (g) [2] 2C O (g) → C (s) + C O 2 (g) [3] C O (g) + H 2 (g) → C (s) + H 2 O (g) [4]…”

“…The syngas, mainly composed of H 2 and CO, can be obtained by gasification of biomass and coal, which are economic, abundant and safe energy resources. 1,2 Moreover, CO and H 2 are also main products of internal reforming of hydrocarbons in SOFCs through steam reforming or partial oxidation. 3 So the fuel flexibility of SOFC anodes critically depends on the catalytic performance for electrochemical oxidation of CO/H 2 at the anodes.…”

Comparison between conventional design and cathode gas recirculation design of a direct-syngas solid oxide fuel cell–gas turbine hybrid systems part II: Effect of temperature difference at the fuel cell stack

“…In Part I of this presentation, Figs. 1 and 3 were used to explain the operation of the hybrid SOFC-GT cycle fuelled with sungas when it was operated in both configurations (Azami et al 2017). The major differences between two cycles are the option which employed for heating cathode inlet stream.…”

“…AC energy efficiencies for the SOFC and GT generator in the system without cathode recirculation were 50.83% and 35.98%, respectively. Also, AC energy efficiencies for the SOFC and GT in the system with cathode recirculation were 50.67% and 37.99%, respectively (Azami et al 2017).…”

“…In the first part of this presentation, it was shown that the cathode gas recirculation, has a major impact on the on both the SOFC and gas turbine performances (Azami et al 2017). In the analysis, first the conventional SOFC-GT hybrid system (CS) was presented.…”