The steadily increasing share of renewable energies in the power supply means that on windy or sunny days more electricity is generated than is currently needed. Possible strategies for the time-flexible use of green electricity are the production of energy sources and basic chemicals via P2X processes.
By combining High Temperature Solid Oxide ELectrolysis (HT-SOEL) and OxyFuel combustion, renewable, C-based P2X fuels and chemicals can be produced with a power requirement of 2,5 kWhel / mN³SynGas. The fundamental technical innovation is the process combination of OxyFuel Combustion and HT-SOEL, in which the oxygen demand of the OxyFuel process is covered by the HT-SOEL and the high temperature heat resulting from the combustion of biomass is coupled into the HT-SOEL. The HT-SOEL is operated in endothermic mode and high-grade electricity is substituted by HT heat from the OxyFuel combustion. Through the oxyfuel combustion, the biomass also functions as a CO2source for P2X processes.
Within the Kopernikus joint project "P2X: Research, validation and implementation of "Power-to-X" concepts" the ZSW has developed a 10 kWth biomass test platform with a fluidized bed and a FLOX® reactor. The experiments on oxyfuel combustion of solid biomass show that oxyfuel flue gases are produced in stoichiometric operation with CO2 contents of almost 99 Vol-%tr. The CO2 produced in this way is used as a starting material for HT-SOEL or syntheses. In parallel, the new P2X path was evaluated using process simulations and an efficiency of about 65% (based on biomass and electricity input) was determined for the renewable natural gas substitute produced in this way. The carbon of the biomass can be completely converted into the renewable target product, which corresponds to an increase in fuel yield of more than five times compared to previous biofuels. The work was funded by the Federal Ministry of Education and Research.