Researchers from several Russian scientific institutions have developed and tested a sustainable aviation fuel (SAF) pathway using pine sawdust and sunflower husks, with laboratory and micro-gas-turbine tests indicating lower pollutant emissions and engine noise than petroleum-derived kerosene.
The research, involving scientists from Tomsk Polytechnic University, the Institute of Thermophysics of the Siberian Branch of the Russian Academy of Sciences, South Russian State Polytechnic University and the Institute of Petrochemistry and Catalysis of the Russian Academy of Sciences in Ufa, converts non-food biomass into synthetic aviation kerosene through gasification, Fischer-Tropsch synthesis and hydroisomerisation.
The resulting biokerosene was evaluated in a micro gas turbine against conventional petroleum-derived kerosene. The reported tests showed reductions in several combustion pollutants and sound pressure, although the biofuel also produced lower maximum thrust.
Pine sawdust and sunflower husks used as SAF feedstock
The researchers selected pine sawdust and sunflower husks as non-food biomass feedstocks, avoiding direct competition with food crops.
The process begins with biomass gasification to produce synthesis gas. The research team used a continuous downdraft gasifier and a steam-air gasification mixture to obtain syngas suitable for subsequent Fischer-Tropsch synthesis.
The published research describes the overall pathway as biomass gasification followed by Fischer-Tropsch synthesis and hydroisomerisation.
Low-aromatic synthetic kerosene
The resulting fuel was reported to contain predominantly isoalkanes, with the Russian research team reporting an approximately 90% isoalkane content. The product also had no aromatic hydrocarbons and minimal sulphur content, according to the South Russian State Polytechnic University research institute.
The low-aromatic composition is relevant because synthetic paraffinic kerosenes can have fuel-system compatibility considerations that need to be addressed during aviation fuel qualification. The researchers therefore evaluated the fuel’s physical, chemical and combustion characteristics rather than treating the absence of aromatics alone as sufficient for aviation deployment.
Micro-gas-turbine tests show lower emissions
The researchers conducted static firing tests using a MGTD-180 micro-gas-turbine engine, comparing the biomass-derived kerosene with petroleum-derived TS-1 kerosene.The university’s research summary confirms that the firing tests assessed thrust, acoustic performance and emissions, and found substantial reductions in nitrogen oxides, sulphur dioxide and carbon monoxide, alongside a reduction in engine noise.
The peer-reviewed study likewise reports testing of throttle characteristics, sound pressure and anthropogenic emissions in a micro-gas-turbine engine.
Lower thrust remains a technical trade-off
The principal performance penalty identified in the tests was lower maximum thrust.
The researchers attribute this to the lower density of the biokerosene, which results in a lower mass flow when fuel is supplied volumetrically. The university’s technical summary specifically identifies fuel density and corresponding mass-flow reduction as the reason for the lower maximum thrust.
This distinction is important because the reported thrust reduction does not necessarily indicate combustion instability or an inability of the engine to operate on the fuel. The research team reported stable operation and faster transient responses during testing.
However, the tests were conducted on a micro gas turbine, rather than a commercial aircraft engine. Consequently, the results should be regarded as experimental evidence of fuel performance rather than proof of commercial aircraft readiness.
Researchers report compatibility with SAF standards
The research team says the fuel’s characteristics meet the requirements associated with ASTM D4054 qualification testing and that the biokerosene can be considered as a component for blending with Jet A-1 at up to 50% under ASTM D7566, while further upgrading would be required for use as a standalone fuel.
This is an important qualification. Meeting or being evaluated against fuel-property requirements is not equivalent to full commercial aviation certification. ASTM D4054 is part of the qualification pathway used to evaluate new aviation fuel technologies, while ASTM D7566 specifies approved synthetic blending components and their blending limits.
The published study describes its work as demonstrating the technical feasibility of the integrated SAF synthesis and combustion-testing pathway.
Economics and scale-up remain key challenges
The use of forestry and agricultural residues could provide a non-food carbon source for SAF production, particularly in regions with established sawmilling and agricultural processing industries.
However, converting heterogeneous lignocellulosic residues into aviation-range hydrocarbons involves several processing stages, including gasification, syngas conditioning, Fischer-Tropsch synthesis and upgrading. The economics of each stage, as well as feedstock collection, transport and preprocessing, will influence the eventual cost of the fuel.
The research itself remains at an experimental stage. The reported testing provides evidence on fuel properties and micro-turbine performance, but commercial-scale production, certification and full-scale aviation engine testing would require additional development.
Bioenergy Business Analysis
The research highlights the potential of second-generation SAF pathways based on lignocellulosic residues, rather than edible oils or dedicated food crops. Pine sawdust and sunflower husks are particularly relevant examples because they are industrial and agricultural residues that can serve as carbon feedstocks without being cultivated specifically for aviation fuel.
The reported emissions and acoustic reductions are notable at the combustion-test level, but they should not automatically be interpreted as equivalent reductions in full life-cycle greenhouse-gas emissions. The climate benefit of biomass-derived SAF depends on factors including feedstock sourcing, land-use effects, gasification energy requirements, hydrogen inputs and process energy. The research demonstrates a technical conversion route and combustion performance; a full commercial assessment would also need a detailed life-cycle and techno-economic analysis.
The 10% reduction in maximum thrust is another issue that will require further evaluation. The researchers link it to the fuel’s lower density rather than unstable combustion, but commercial aviation applications impose stringent requirements on energy density, fuel-system compatibility and engine performance. The university research institute itself describes the current material as suitable for blending with Jet A-1 under the cited framework, with further processing needed before considering it as a standalone fuel.
