Performance analysis and multi-objective optimization with safety constraints for a solid oxide co-electrolysis cell system integrated with a Fischer-Tropsch reactor

Abstract

Renewable energy plays a pivotal role in advancing global carbon reduction and fostering a low-carbon society. However, its intermittent instability and seasonal variability often demand efficient energy storage solutions. An effective approach to address this challenge involves the use of solid oxide electrolysis cells (SOEC) coupled with Fischer-Tropsch (FT) synthesis technology, which converts electricity into fuel for long-term storage. Nevertheless, the fluctuating power supply poses significant challenges in balancing system safety and efficiency through adaptable operating parameters and performance stability. In this paper, a SOEC-FT system with heat recovery is proposed, and the effects of critical parameters on SOEC performance, power consumption distribution, and system efficiencies are studied in detail. Additionally, the operating windows and performance maps that consider the system conversion rate (SCR) and voltage as system safety constraints are established. And the second-generation nondominated sorting genetic algorithm (NSGA-II) was employed to identify optimal operating conditions that maximize both system efficiency and system conversion rate. The results indicate that higher system efficiency leads to a lower SCR. And at the optimal solution, the system efficiency and SCR can reach 60.7 % and 74.7 %, respectively. This paper can provide guidance for online adjustment of key operating parameters.