Performance Enhancement of a Molten Carbonate Fuel Cell/Micro Gas Turbine Hybrid System With Carbon Capture by Off-Gas Recirculation

Abstract

The demand for clean energy continues to increase as the human society becomes more aware of environmental challenges such as global warming. Various power systems based on high-temperature fuel cells have been proposed, especially hybrid systems combining a fuel cell with a gas turbine (GT), and research on carbon capture and storage (CCS) technology to prevent the emission of greenhouse gases is already underway. This study suggests a new method to innovatively enhance the efficiency of a molten carbonate fuel cell (MCFC)/micro GT hybrid system including carbon capture. The key technology adopted to improve the net cycle efficiency is off-gas recirculation. The hybrid system incorporating oxy-combustion capture was devised, and its performance was compared with that of a post-combustion system based on a hybrid system. A MCFC system based on a commercial unit was modeled. Externally supplied water for reforming was not needed as a result of the presence of the water vapor in the recirculated anode off-gas. The analyses confirmed that the thermal efficiencies of all the systems (MCFC stand-alone, hybrid, hybrid with oxy-combustion capture, hybrid with post-combustion capture) were significantly improved by introducing the off-gas recirculation. In particular, the largest efficiency improvement was observed for the oxy-combustion hybrid system. Its efficiency is over 57% and is even higher than that of the post-combustion hybrid system.

Advanced Control to Improve the Ramp-Rate of a Gas Turbine: Optimization of Control Schedule

“…During load-following operation, the rotation speed of the shaft changes due to imbalance between the load (i.e., power demand) of the generator and the actual power output of the GT. The change in rotation speed was calculated using Equation (13), which reflects the rotating inertia. The rotating inertia was set to 42,000 kgm 2 by referring to the value in the literature on the same F-class GT [37].…”

“…Furthermore, studies have been conducted on power-to-liquid (P2L) systems that store liquid fuel [12]. Studies have also been conducted on the performance of a hybrid system that was combined with a carbon capture system, fuel cell, and GT [13]. Studies were also conducted on a hydrogen turbine using hydrogen as fuel [14].…”