Syngas to SAF
Syngas to SAF is a fuel production pathway in which synthesis gas is converted into synthetic hydrocarbons and upgraded into sustainable aviation fuel.
Synthesis gas, or syngas, contains hydrogen and carbon monoxide and serves as the intermediate feedstock for Fischer-Tropsch fuel production pathways.
How does syngas become sustainable aviation fuel?
Syngas becomes sustainable aviation fuel when hydrogen and carbon monoxide are converted through Fischer-Tropsch synthesis into liquid hydrocarbons that are later upgraded into jet-range fuel molecules.
The pathway typically includes:
- Feedstock conversion into syngas
- Gas cleaning or polishing
- Fischer-Tropsch synthesis
- Product upgrading into aviation fuel fractions
The final aviation blending component produced through this route is Fischer-Tropsch Synthetic Paraffinic Kerosene (FT-SPK).
What is syngas made from?
Syngas can be produced from multiple carbon sources depending on the chosen production pathway.
As shown in the process pathways in the previous section, syngas can come from:
Biogas pathways
Landfill gas, digester gas
Solid waste and biomass pathways
Municipal waste, woody biomass, forestry residues, agricultural residues
Power-to-liquids pathways
Renewable electricity, water, and captured carbon dioxide
This feedstock flexibility is one reason syngas-based SAF pathways attract broad interest.
Why is syngas important in SAF production?
Syngas creates a common chemical starting point for producing synthetic hydrocarbons from very different feedstocks.
When syngas reaches the correct hydrogen-to-carbon monoxide ratio, the downstream fuel synthesis chemistry becomes consistent regardless of upstream carbon source.
This enables very different carbon inputs to converge into a common fuel production pathway.
With the reliance of other SAF pathways such as HEFA and alcohol-to-jet on finite waste oils and food crop feedstocks, FT SPK from syngas is a strong contender for meeting the shortage in SAF supply projected by multiple agencies.
How is syngas prepared before Fischer-Tropsch synthesis?
Syngas must be cleaned and conditioned before entering a Fischer-Tropsch reactor.
Preparation may include:
- gas clean-up
- syngas polishing
- contaminant removal
- H2 to CO ratio adjustment
This protects catalyst performance and supports stable reactor operation.
For reaction fundamentals, see Fischer-Tropsch catalyst.
Why does Fischer-Tropsch sit at the center of syngas-based SAF production?
Fischer-Tropsch synthesis is the chemical step that converts syngas into liquid hydrocarbons.
When syngas enters the reactor:
- carbon monoxide reacts with hydrogen
- hydrocarbon chains form on the catalyst surface
- synthetic liquids are produced for upgrading
This makes Fischer-Tropsch the hydrocarbon-building stage of the pathway.
What happens after Fischer-Tropsch synthesis?
The synthetic liquids produced through Fischer-Tropsch synthesis must be upgraded into finished fuel fractions.
Product upgrading separates hydrocarbons into usable outputs such as:
- sustainable aviation fuel
- renewable diesel
- naphtha
- LPG
This upgrading stage determines final product slates.
Can syngas-based SAF use renewable electricity?
Yes. In Power-to-liquids systems, renewable electricity is used to produce hydrogen through electrolysis, which then combines with carbon dioxide to generate syngas.
This pathway allows synthetic aviation fuel production using non-biogenic carbon inputs.
See Power to liquids.
Why is syngas-to-SAF considered feedstock-flexible?
Because many carbon sources can be converted into syngas before fuel synthesis begins.
This flexibility enables project developers to match:
- local feedstock availability
- carbon source strategy
- infrastructure access
to one common fuel synthesis platform.
How does syngas to SAF differ from oil-based SAF pathways?
Syngas-based SAF first converts feedstock into gas, while oil-based pathways directly hydroprocess lipid feedstocks.
For example:
Syngas-based pathway
Feedstock → syngas → Fischer-Tropsch → upgrading
HEFA pathway
Oil feedstock → hydrotreating → upgrading
See FT vs HEFA.
Frequently asked questions
Is syngas a fuel?
It is a precursor to fuel. Syngas is an intermediate gas mixture used for chemical conversion, as opposed to a finished aviation fuel.
Does syngas always come from biomass?
No. Syngas can also come from biogas, waste, natural gas, or synthetic carbon systems.
Is Fischer-Tropsch required in syngas-based SAF?
In FT SAF pathways, yes. Fischer-Tropsch is the hydrocarbon synthesis step.
Can syngas produce fuels other than SAF?
Yes. It can also produce renewable diesel, naphtha, LPG, FT wax, and other hydrocarbon products.