Upcycling of CO₂ into sustainable hydrocarbon fuels via the integration of Fe-based Fischer-Tropsch synthesis and olefin oligomerization: A comparative case study

Power-to-X (PtX) technologies, especially for the Power-to-Liquids (PtL) and Power-to-Gas (PtG) have attracted extensive attention recently, as promising pathways for carbon upcycling via converting CO₂ into high-value products including liquid fuels and substitute natural gas (SNG). Herein, aiming at further improving the PtX process efficiency, we proposed two novel PtL/PtG hybrid processes, namely an indirect process (with RWGS unit) and a direct process (without RWGS unit) by integrating Fe-based Fischer-Tropsch synthesis (FTS) and olefin oligomerization technologies, which co-produce syncrude and SNG. Both process simulation and techno-economic analysis were implemented to evaluate the overall process performances, through various indicators involving technical indicators (e.g., syncrude production, energy efficiency, and net CO₂ reduction), and economic indicators such as total capital investment, net CO₂ reduction costs together with total product costs. Both proposed PtL/PtG processes are efficient in converting CO₂ into valuable hydrocarbon fuels, and the syncrude production and total product revenues of indirect process are 2.35–14.58% and 7.55–8.51% higher than those of the direct process, respectively. Whereas, the direct process has lower net CO₂ reduction cost of 206.09 $/tonne CO₂. Moreover, the present PtL/PtG processes have higher syncrude production and total product revenues than those of our previous studies including a direct PtL/PtG process coupled with Fe-based FTS and two indirect PTL/PTG processes combined with RWGS and Fe/Co-based FTS reaction, with rates of 30.95 and 12.73% at most.