Electrification of the production of sustainable aviation fuels (SAF) - co-electrolysis boosts efficiency
TUM.PtX News |
As part of the global effort to reduce greenhouse gases, the Chair of Energy Systems (LES) complements the previously proposed option for the electrification of biomass-to-X (BtX) processes with its current paper. Building on this work, solid oxide electrolysis (SOEL) has now been integrated into a biomass-to-liquid (BtL) process that enables the production of sustainable aviation fuel (SAF) through gasification, co-electrolysis and Fischer-Tropsch synthesis. Two different integration concepts were developed: An in-line integration leading to a directly electrified biomass-to-liquid (eBtL) process and a parallel integration for a power-and-biomass-to-liquid (PBtL) process. To maximize process efficiency, the SOEL is operated under endothermic conditions with heat input from syngas cooling after gasification.
The developed processes make it possible to increase the carbon efficiency to around 61% to 94%. The required electrolysis power corresponds to electrification levels of 0.32 to 0.83 MWel/MWth. Compared to conventional Hydrogen addition in PBtL processes, the electricity requirement can be reduced by 13% to 29% when using co-electrolysis instead of steam electrolysis. The resulting increase in energy yield and energy efficiency is due to the fact that up to 17% of the SOEL energy requirement can be replaced by heat in the electrified BtL processes.
A life cycle analysis (LCA) shows the absolute necessity of operating the process with renewable electricity in order to reduce indirect greenhouse gas emissions. A critical assessment of the technological feasibility shows further development needs for the SOEL and the gasification heat recovery technology to enable the integration approach.
Contact: Marcel Dossow, Sebastian Fendt
We would like to thank the Federal Ministry of Education and Research for funding the “REDEFINE H2E” project (01DD21005). The authors would also like to thank the TUM.Hydrogen and PtX.