A Solar-Hybrid Power Plant Integrated With Ethanol Chemical-Looping Combustion

Abstract

In this paper, a new solar hybrid gas turbine cycle integrating ethanol-fueled chemical-looping combustion (CLC) has been proposed, and the system was investigated with the aid of the Energy-Utilization Diagram (EUD). Chemical-looping combustion consists of two successive reactions: first, ethanol fuel is oxidized by metal oxide (NiO) as an oxygen carrier (reduction of metal oxide); secondly, the reduced metal (Ni) is successively oxidized by combustion air (the oxidation of metal). The reduction of NiO with ethanol requires a relative low-grade thermal energy at 150–200°C. Then concentrated solar thermal energy at approximately 200–300°C can be utilized to provide the process heat for this reaction. The integration of solar thermal energy and CLC could make the exergy efficiency and the net solar-to-electric efficiency of the system more than 54% and 28% at a turbine inlet temperature (TIT) of 1288°C, respectively. At the same time, the variation in the overall thermal efficiency (η) of the system with varying key parameters was analyzed, such as Turbine Inlet Temperature, pressure ratio (π) and the temperature of reduction reactor. Additionally, preliminary experiments on ethanol-fueled chemical-looping combustion are carried out to verify the feasibility of the key process. The promising results obtained here indicate that this novel gas turbine cycle with ethanol-fueled chemical-looping combustion could provide a promising approach of both efficient use of alternative fuel and low-temperature solar thermal and offer a technical probability of combining the chemical-looping combustion with inherent CO2 capture for the alternative fuel.