Experimental Investigation of Efficiency Maximization in Solid Oxide Electrolysis Systems by Internal Steam and Heat Recovery

Abstract

This study presents the development of a scalable steam generator for a reversible solid oxide cell system with 40 kW of power in electrolysis mode. As solid oxide electrolysis can be conducted under thermal-neutral conditions, efficiency is primarily governed by the system’s heat and steam loss. The steam generator presented herein recovers heat and steam from the fuel side off-gas in order to preheat the feed water and superheat the electrically-generated saturated steam. The design is based on a pinch analysis intended to optimize the temperature levels. In the considered system, the steam generator was estimated to increase electrolysis efficiency from 70% to more than 74%.