Thermal impact performance study for the thermal management of ammonia-fueled single tubular solid oxide fuel cell

Abstract

With the substantial improvement of the direct ammonia fuel cells performance, it has become the key to the further development of ammonia fuel cells to deeply understand the heat and mass transfer process inside the cell and to study the thermal impacts generation mechanism during cell operation. In this paper, a whole-cell model of single tubular direct ammonia cracking solid oxide fuel cell (SOFC) is established, and the generation mechanism of thermal impacts inside the cell is analysed in a data-driven method. The model includes the coupling of chemical-electrochemical reactions, local current, local temperature, mass flow and energy transfer inside the cell. It's identified from model simulations that the key to the thermal impact optimization of direct ammonia cracking SOFCs is to reduce the effect of the excessively fast and unbalanced ammonia cracking reaction on the cell. Both introducing the ammonia pre-reforming reaction and improving the activation energy of the ammonia cracking reaction can increase the overall average temperature of the cell and improve the temperature distribution. The 96% ammonia pre-reforming SOFCs can improve the extreme temperature difference in the anode from 37.71 K to 0.52 K at the operating temperature of 800 °C. Increasing activation energy of ammonia cracking reaction by 1.5 times can also make the ammonia cracking reaction rate distribution more uniform at the fuel channel, it can improve the extreme temperature difference in the anode to 4.49 K. This study can enrich the basic theory and research methods of thermal management of direct ammonia cracking SOFCs, and provide theoretical support for further improving cell performance.