H
Syngas
Light hydrocarbons
Light hydrocarbons
Gasoline / diesel
C -C
C -C +
MeOH
H
H
H C H
OH
Hydrogen source
Methanol synthesis
Methanol-to- Ole ns
Oligomerisation
Hydrogenation
Sustainable aviation fuel
Catalyst: Reduced metal T=100 - 250˚C P=20 - 50 bar
Catalyst: Solid acid T=220 - 250˚C P=30 - 50 bar
Catalyst: Zeotypes T=400 - 500˚C P=1 - 3 bar
Catalyst: Cu-based T=220 - 280˚C P=30 - 80 bar
CO x
Carbon source
Water
Water Aromatics
Figure 3 SAF production from hydrogen and carbon source via the methanol pathway (Elwalily, et al., 2025)
followed by oligomerisation, cyclisation, and aromatisation (see Figure 3 ). The primary catalyst is based on zeolite, H-ZSM-5; its medium-pore structure and strong Brønsted acidity enable shape-selective formation of high-octane products while limiting heavy fractions (Sanz-Martinez, et al., 2022) . The Si/Al ratio governs acidity and stability, with higher values promoting aromatic selectivity and reducing coking. MTG has progressed from fixed-bed designs to fluidised-bed systems that integrate methanol dehydration and gasoline synthesis,
improving heat management and energy efficiency. Industrial demonstrations proved the scalability of fixed-bed systems, while ExxonMobil’s fluidised-bed pilot plant enhanced energy efficiency, reduced Capex/Opex, and simplified process integration. Remaining challenges include catalyst deactivation, dealumination during regeneration, and heat/ water management; hydrophobic zeolites and dual-bed configurations address these limitations. MTG’s future deployment depends on improved catalyst stability, heat control, and process optimisation for a sustainable low- carbon fuel future.
Process route
ASTM D7566
Blending limit
Methanol-to-jet (MTJ) MTJ is a power-to-liquids pathway that links renewable methanol to sustainable aviation fuel (SAF) (see Figure 4 ). Since methanol is derived from CO or CO₂, MTJ avoids RWGS/ co-electrolysis and can pair dynamically with variable renewable power. Its exothermic upgrading steps enable internal heat recovery, low utilities, and high jet yields with limited light-hydrocarbon formation – unlike FT
Annex 2 HEFA-SPK
50%
Hydroprocessed Esters and Fatty Acids (HEFA)
Annex 7 HC-HEFA-SPK
10%
Catalytic Hydrothermolysis Jet (CHJ)
Oil based biomass
Annex 6 CHJ
50%
Annex 3 SIP
10%
Synthesised iso- para ns (SIP)
Sugar/starch biomass
Biological origin (Biofuel)
Annex 5 AtJ-SPK
50%
Alcohol-to-jet (AtJ)
Annex 8 AtJ-SPK
50%
Lignocellulosic biomass
SAF
Annex 1 FT-SPK
50%
Fischer-Tropsch (FT)
Annex 4 FT-SPK/A
50%
Hydrogen and carbon source
Non-biological Origin (PTL)
Methanol-to-Jet (MTJ)
Not yet annexed
-
Figure 4 Production routes for SAF – approved and pending (Elwalily, et al., 2025)
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