Fischer Tropsch synthetic paraffinic kerosene - FT SPK
Fischer-Tropsch synthetic paraffinic kerosene (FT SPK) is an aviation fuel blending component produced by upgrading hydrocarbons generated through Fischer-Tropsch synthesis.
FT-SPK is one of the approved pathways under aviation fuel standards for sustainable aviation fuel and can be blended with conventional jet fuel for commercial use.
What is Fischer-Tropsch synthetic paraffinic kerosene?
Fischer-Tropsch synthetic paraffinic kerosene is a synthetic aviation fuel fraction produced from Fischer-Tropsch hydrocarbons after upgrading and refining.
The process begins with synthesis gas, which is converted into synthetic hydrocarbons through Fischer-Tropsch synthesis. These hydrocarbons are then hydroprocessed into jet-range molecules suitable for blending with aviation fuel.
FT-SPK is commonly referred to as one of the main second-generation Fischer-Tropsch SAF pathways.
What does FT-SPK stand for?
FT SPK and FT-SPK are abbreviations for Fischer-Tropsch synthetic paraffinic kerosene.
It describes:
- Fischer-Tropsch origin
- Synthetic hydrocarbon composition
- Paraffinic molecular profile
- Kerosene-range boiling characteristics
FT SPK is chemically similar to conventional aviation kerosene, but is produced from non-petroleum feedstocks.
How is FT SPK produced?
FT-SPK is produced by upgrading Fischer-Tropsch liquids into aviation-range hydrocarbons.
The process includes:
- Producing syngas from biomass, waste, biogas, or renewable hydrogen and carbon dioxide
- Performing Fischer-Tropsch synthesis
- Upgrading the synthetic hydrocarbons through hydroprocessing
- Separating jet-range fractions
This produces fuel molecules suitable for blending into commercial aviation fuel.
For reaction fundamentals, see Fischer-Tropsch synthesis.
Is FT-SPK approved for aviation use?
Yes. FT SPK is approved under ASTM International D7566 as a sustainable aviation fuel pathway.
ASTM approval means FT-SPK:
- Meets strict fuel property requirements
- Can be blended with conventional Jet-A
- Is compatible with existing aircraft and fueling systems
FT-SPK is one of several approved synthetic aviation fuel pathways.
For broader pathway context, see ASTM approved SAF pathways.
Why is FT SPK blended with conventional jet fuel?
FT-SPK is blended because synthetic paraffinic kerosene contains very low aromatic content compared with conventional jet fuel.
Aromatic compounds are important for certain seal-swelling properties in aircraft fuel systems.
Blending ensures:
- Full compliance with aviation fuel specifications
- Compatibility across aircraft fleets
- Stable fuel performance in commercial use
How is FT-SPK different from conventional jet fuel?
FT SPK is chemically cleaner and more uniform than petroleum-derived jet fuel but has a narrower composition range.
Compared with fossil jet fuel, FT-SPK typically contains:
- Very low sulfur
- Very low aromatics
- High paraffinic purity
These properties can improve combustion quality while lowering certain emissions.
What feedstocks can produce FT SPK?
FT-SPK can be produced from any feedstock capable of generating clean synthesis gas.
Common feedstocks include:
- Biomass
- Municipal solid waste
- Biogas
- Renewable hydrogen and captured or biogenic CO₂
Because the FT process begins with syngas, feedstock flexibility is one of its major strengths.
See Syngas to SAF for pathway context.
Why is FT-SPK important for sustainable aviation fuel?
FT SPK provides one of the most scalable synthetic pathways for producing drop-in sustainable aviation fuel.
It supports SAF production because:
- It uses widely available feedstocks
- It produces hydrocarbons compatible with aviation systems
- It fits within existing refinery and fuel logistics
FT-SPK is especially important in and power-to-liquids pathways.
Is FT SPK commercially proven?
Yes. FT-SPK has been produced and used in commercial aviation demonstrations and approved fuel programs.
SAF produced using Velocys Fischer-Tropsch technology was flown commercially by Japan Airlines in 2021.
This demonstrated the practical use of FT-derived aviation fuel from biomass-derived feedstocks.
Frequently asked questions
Is FT-SPK the same as SAF?
FT-SPK is one approved SAF blending component, but SAF includes multiple approved pathways.
Can FT SPK be used without blending?
Current standards require FT-SPK to be blended with conventional jet fuel.
Does FT-SPK contain sulfur?
FT-SPK contains very low sulfur compared with fossil-derived jet fuel.
What is upgraded to make FT SPK?
Synthetic hydrocarbons produced during Fischer-Tropsch synthesis are hydroprocessed into jet-range molecules.