EFFICIENCY OF METHANE-FUELED PROTONIC CERAMIC FUEL CELLS AND ENERGY SYSTEMS ON THEIR BASES

Abstract

The relevance of the research is caused by the necessity to develop new materials for fuel cells, in particular, protonic ceramic fuel cells, as well as methods for assembling fuel cell stacks. Prospects for using this type of fuel cell at the level of energy systems are studied to a small extent. Fuel cells are highly efficient generators of electrical energy, which, unlike traditional heat engines, directly convert chemical energy of fuel into electrical energy through an electrochemical reaction, without intermediate stage of fuel combustion. The main aim of the research is to develop the concept of organizing highly efficient, sustainable at uneven power load energy systems based on methane-fueled protonic ceramic fuel cells, to calculate the technical parameters of the proposed systems based on the current-voltage characteristics of the elementary cells of fuel cells. Objects: protonic ceramic fuel cells with BZY20 and BCZYYB types of anodes; methane-fueled power, heat and hydrogen generating systems based on proton conducting ceramics. Methods: development of quasi-equilibrium models based on the current-voltage characteristics of elementary protonic ceramic fuel cells in the fuel cell and electrolyzer modes; analysis and description of the properties of promising developments in the field of proton conducting ceramics, a theoretical study of the behavior of this type of fuel cells when combined into energy complexes. Results. The authors have developed a quasi-equilibrium model of the energy system based on methane-fueled protonic ceramic fuel cells with cathode-anode recirculation and a partial transition to high-temperature electrolysis mode at partial power load. The main energy parameters of the system and the evaluation of efficiency are provided. The authors carried out the analysis of the phase diagram of the evolution of the fuel mixture composition at the anode in the vapor-oxygen reforming of methane by cathode-anode recirculation of gases. To determine the optimal operating point of the current-voltage characteristics, as well as to express the absolute efficiency of energy systems based on fuel cells, the «Effective power density» value was introduced.

Keywords

• proton conducting ceramic
• fuel cell
• methane reforming
• electrolysis
• solid oxide fuel cell