From CO ₂ to Jet Fuel: Techno-Economic and Life-Cycle Assessment

This work investigates the advantages of recycling and introducing reforming stages to enhance jet fuel production in a Power-to-Liquid (PtL) process while reducing direct air emissions. A flue gas stream containing 8%vol of CO2 is considered, being the CO2 captured via amine scrubbing units, and converted to jet fuel via a reverse water gas shift reaction, followed by a Fischer–Tropsch synthesis, and separated in an Atmospheric Crude Distillation Unit (ACDU). Three production scenarios are considered: the Base scenario, where CO2 is not recycled within the process; the Recycle scenario, which separates and recycles unreacted CO2 and H2 to the reverse water gas shift reactor, via amine scrubbing systems and pressure swing adsorption; and the Recycle + Reforming scenario, which, in addition to CO2 recycling, also converts unreacted hydrocarbon to syngas in a reforming reactor to be added to the Fischer–Tropsch reactor. Aspen Plus V12.1 is used for simulating the proposed scenarios, and the results are used to estimate the levelized costs of fuel and to perform the Life Cycle Assessments. The median values of the jet fuel production cost obtained in the Recycle and Recycle + Reforming scenarios are about half of that obtained in the Base scenario and very similar to each other, 2.7–3.7 €/L, and 2.7–3.6 €/L, respectively. The lowest bound of the range is in line with the available projections for jet fuel prices but is highly dependent on the selling of byproducts, such as electricity, steam, Liquefied Petroleum Gas (LPG), naphtha, and diesel, particularly for the Recycle case. Despite the increase in water and mineral resources use, these solutions reduce jet fuel Global Warming Potential (GWP), ranging from 27 to 59 gCO2eq/MJ with system expansion, or about 37 gCO2eq/MJ with energy allocation and assuming that green H2 production impacts are zero. Using renewable energy-powered electricity would be enough to decrease the footprint to levels lower than 28.2 gCO2eq/MJ, thus complying with the 70% emissions saving criterion established for renewable transport fuels of nonbiological origin in the European Union.