Co-Electrolysis Performance and Process Analyses for Synthetic Liquid Fuel Production

Abstract

To achieve carbon neutrality in 2050, carbon recycle technology is attracting much attention coupled with renewable power and electrolyzers to produce “green” fuels such as methane and synthetic oil. We have just started a new NEDO project (FY2020-2024) in Japan for synthetic liquid fuel production using solid oxide electrolysis cells (SOECs) and Fischer-Tropsch (FT) synthesis, which will give higher efficiencies compared to one with water electrolysis at low temperatures. In particular, the project aims at FT oil production from gasoline to diesel fractions (C5-C19) to avoid wax production. We are responsible for R&D of co-electrolysis process for the FT synthesis, cell/stack performance evaluation for the co-electrolysis, and evaluate state-of-the-art commercial single cells and stack that are developed for fuel cell application. Since carbon deposition at higher H2O/CO2 utilization is of concern, material analysis of such cells/stacks will be also carried out to elucidate optimal electrolysis operative conditions and to suggest cell and peripheral components design optimal to syngas production (H2/CO ~ 2.0). In the conference, we will report that developed SOEC performance evaluation methods for co-electrolysis which precisely control steam flowrate, giving cell voltage stability at ± 0.1 mV level. I-V characteristics of commercial cells and 1-2 kW class stack will also be presented at various operative conditions in combination of post-test analysis after the short-term cell/stack evaluation to discuss carbon deposition conditions for syngas production for FT synthesis. Furthermore, numerical process simulation results will be presented to discuss possible energy efficiency of the combined system with SOEC and FT synthesis.