Development of a Solid Oxide Electrolysis Stack Able to Operate at High Steam Conversion Rate and Integration into a SOE System

Abstract

Solid Oxide Electrolysis (SOE) technology is considered to be a highly efficient process to produce hydrogen. Steam conversion rate is one of the key parameters in the overall system efficiency. The present paper presents the methodology undertaken to develop a stack design able to operate at high steam conversion rates (80% or above). It has been shown that with these design modifications, i-V curves can be recorded up to a steam conversion rate of 100%. The apparition of limiting current is shifted to values much above 75%. It has been found that the design modification not only allows to reach higher steam conversion rates, but also improves the gas distribution homogeneity into the stack. Finally, a 25-cell stack with the modified design has been integrated into a SOE system including all BoP components. It has been possible to operate it up to a value of steam conversion of 80%.