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Cited by 170Advanced Aircraft Design and TechnologiesHeat transfer and supercritical fluidsAdvanced Combustion Engine Technologies

Sustainable aviation fuel prescreening tools and procedures

Open access
Heyne, Joshua, Rauch, Bastian, Le Clercq, Patrick, Colket, Meredith·2021·Fuel
DOI 10.1016/j.fuel.2020.120004
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Abstract

This paper outlines the benefits and procedures for prescreening Sustainable Aviation Fuel (SAF) candidates before entering the official ASTM D4054 evaluation process. Specific properties are identified, that if not met, may result in extensive and costly efforts to correct if not recognized until later in the fuel development process. Hence, an approach with specific techniques that use low fuel volumes is suggested that enable (1) early estimates of critical properties and subsequently (2) direct measurement of these properties to guide fuel processing development prior to formally entering the ASTM evaluation process. The process is demonstrated with two exemplary candidate fuels.

AI snapshot

Written from the paper’s full text.

TL;DR

This paper proposes a two-tier prescreening approach (Tier α and Tier β) to evaluate sustainable aviation fuel (SAF) candidates before formal ASTM D4054 evaluation, using low fuel volumes to identify costly property problems early. It demonstrates the approach on two candidate fuels, showing one would fail due to alkenes/oxygenates and the other appears favorable aside from density that can be resolved by blending.

Key findings

  • Candidate fuel 1 contained 21% n-/iso-alkenes and 3% oxygenates, which would violate ASTM D1655 and D7566 compositional requirements and likely fail thermal stability and water solubility tests.
  • Candidate fuel 2 had a composition similar to an approved ASTM D7566 FT-SPK fuel, with an average carbon number of approximately 12.2; its only predicted property outside ASTM D1655 specification range was density, which at a 50/50 blend with Jet A/A-1 would not be an issue and lay within the experience range of approved SAFs.
  • Tier α requires 1–5 mL of fuel for GCxGC composition analysis and correlative property prediction, while Tier β requires 150–500 mL for direct property measurements, with DCN alone requiring ~140 mL; formal ASTM D4054 entry requires ~400 L.
  • The paper argues that traditional correlations based solely on petroleum/distillate fuels may contain bias when applied to synthetic fuels, and that in at least one case (heat of combustion) modeling may give greater precision than the ASTM method.

Methods

  • Design: a proposed prescreening process outside ASTM D4054, consisting of Tier α (composition-based screening with model-based property predictions) and Tier β (experimental verification of Tier α predictions).
  • Data/sample: demonstrated on two exemplary candidate fuels—Candidate fuel 1 (an FT research fuel) and Candidate fuel 2 (POSF 5018)—with comparisons to ASTM D7566 approved synthetic hydrocarbons and 57 conventional fuels from the CRC World Fuel Survey.
  • Analysis: GCxGC hydrocarbon type analysis plus two complementary modeling approaches—DLR Gaussian Process Regression trained on conventional and synthetic fuels, and UD predictions using a database of 1226 molecules with random sampling—compared against ASTM D1655 limits and conventional Jet A/A-1 property ranges.

Limitations

  • The paper states that the models used are not described in detail, that uncertainties from fits of existing data sets are unlikely to represent predictive capability for fuel types not in the fitting routines, and that correlations based on petroleum/distillate fuels may not apply to synthetic aviation fuels.
  • The paper notes no standard uncertainties are established for surface tension, DCN values are not available from DLR, hydrogen content is not reported due to negligible method differences, and the UD HOC model needs clarification with more detailed uncertainty quantification.
  • Evident from the text: the prescreening is demonstrated on only two candidate fuels, and the authors recommend further Tier β evaluation after production scale-up before submitting 400 L for formal ASTM D4054 evaluation, indicating the approach is not a substitute for full qualification.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.1016/j.fuel.2020.120004

Cites

28 of 28 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

0 of 32 cited sources checked · 0 supported · 0 flagged

  • Findingown data

    Besides density, all properties of Candidate fuel 2 satisfy the requirements.

    “It was shown that besides density, which can be resolved by appropriate blending ratios and was in the experience range of approved fuels, all properties satisfy the requirements.”
    Quote in the paperSubstantial claim
  • Findingown data

    The measurement accuracy is typically better than the Tier α predicted uncertainty, with one exception.

    “The measurement accuracy is typically better than the Tier α predicted uncertainty, with one exception.”
    Quote in the paperNot a substantial claim
  • Findingreasoning

    The heat of combustion (HOC) prediction for UD has lower variability than the ASTM method.

    “The heat of combustion (HOC) prediction for UD also has lower variability than the ASTM method.”
    Quote in the paperNot a substantial claim
  • Findingnone given

    A set of techniques to characterize the fuel while requiring low fuel volumes along with correlation methods have been identified that have the potential for estimating key properties.

    “A set of techniques to characterize the fuel while requiring low fuel volumes along with correlation methods have been identified that have the potential for estimating key properties.”
    Quote in the paperSubstantial claim
  • Findingnone given

    The freeze point range amongst 73 iso-alkane isomers with 10 carbons is 158°C.

    “As an extreme example within that database, the freeze point range amongst 73 iso-alkane isomers with 10 carbons is 158 • C.”
    Quote in the paperNot a substantial claim
  • May combine two claims. 23
  • Classified as probably not a substantial claim. 22

  • May combine two claims.

    Findingown data

    Candidate fuel 1 contains 21% of n-/iso-alkenes and 3% of oxygenates, which would violate the compositional requirements in ASTM D1655 and D7566.

    “Here Candidate fuel 1 was found to contain 21% of n-/iso-alkenes and 3% of oxygenates, which would violate the compositional requirements in ASTM D1655 and D7566.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Candidate fuel 2 is within the range of an approved ASTM D7566 FT-SPK fuel and consistent with compositions within ASTM D1655 and D7566.

    “Candidate fuel 2, however, is more consistent with compositions within ASTM D1655 and D7566; namely, it is within the range of an approved ASTM D7566 FT-SPK fuel.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based). May combine two claims.

    Findingnone given

    The property predictions of Tier α are nominally in good agreement with the property measurements and the associated errors.

    “The property predictions of Tier α are nominally in good agreement with the property measurements and the associated errors.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Candidate fuel 2 composition is largely n- and iso-alkanes with no aromatics and minimal monocycloalkanes.

    “The composition of Candidate fuel 2 is largely n-and iso-alkanes with no aromatics and minimal monocycloalkanes.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    The average carbon number of Candidate fuel 2 is approximately 12.2, slightly above the composition of an average Jet A.

    “The average carbon number of Candidate fuel 2 is approximately 12.2 carbon numbers, which is slightly above the composition of an average Jet A.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    The Tiered Test Program currently has seven approved fuels and six annexes and allows approved blend ratios up to 50% with conventional fuel.

    “The Tiered Test Program currently has seven approved fuels and six annexes [5], and currently allows approved blend ratios up to 50% with conventional fuel.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [5] source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Global aviation contributed 3.5% of the net anthropogenic effective radiative forcing in 2011.

    “The contribution of global aviation in 2011 was calculated to be 3.5% of the net anthropogenic effective radiative forcing [1].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [1] source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S2 (checkable), S4 (based). May combine two claims.

    Interpretationreasoning

    Low fuel volume testing procedures could be used to identify new candidate jet fuels with a high probability for evaluation or provide feedback to identify problem areas with troublesome candidate fuels.

    “Low fuel volume testing procedures could be used to identify new candidate jet fuels with a high probability for evaluation or provide feedback to identify problem areas with troublesome candidate fuels.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S2 (checkable).

    Interpretationreasoning

    The complexity, cost, and timeliness of the traditional Tiered evaluation process warrant methods and procedures to minimize resources.

    “The complexity, cost, and timeliness of the traditional Tiered evaluation process warrant methods and procedures to minimize resources.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    The ASTM D4054 process ranges from relatively inexpensive Tier 1 and 2 laboratory tests to more expensive and time-consuming engine and flight tests and final review and balloting by all ASTM committee members.

    “The process ranges from the relatively inexpensive Tier 1 and 2 (laboratory) tests to the more expensive and time-consuming engine and flight tests [10], and final review and balloting by all ASTM committee members.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [10]

      Not checked in the free run.

  • May combine two claims.

    Interpretationreasoning

    These tools offer an opportunity to evaluate a SAF's acceptability for aviation applications before the fuel formally enters the evaluation process and enables feedback to the producer to fine-tune the formulation or workup stages and handling.

    “These tools offer an opportunity to evaluate a SAF's acceptability for aviation applications before the fuel formally enters the evaluation process and enables feedback to the producer to fine-tune the formulation or workup stages and handling.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationreasoning

    Systematic compositional characterization of already approved fuels helps to elucidate the fuel composition-fuel property relation and identify potential fuel chemical families or specific molecules that will bring a fuel candidate outside or inside specification requirements.

    “Systematic compositional characterization of already approved fuels helps to elucidate the fuel composition-fuel property relation in particular when it comes to identifying potential fuel chemical families (e.g., alkenes, oxygenates) or specific molecules (e.g., hetero-atomic compounds) that will bring a fuel candidate outside (or inside) the specification requirements.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisecitation

    Ref. [20] includes 78 fuels, with 3 of these fuels being 'upgraded synfuels' from the direct hydroliquifaction of black and brown coal.

    “Ref. [20] includes 78 fuels, with 3 of these fuels being 'upgraded synfuels' from the direct hydroliquifaction of black and brown coal.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [20] source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S4 (based).

    Premisenone given

    Properties are a function of the composition of the fuel.

    “As properties are a function of the composition of the fuel, one of the first steps in prescreening is to analyze the fuel composition of the candidate fuel blendstocks.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationcitation

    Data derived from Vozka and Kilaz summary table of the lowest error experimental methods appear very promising.

    “In fact, data derived from their summary table of the lowest error experimental methods appear very promising, as shown in Table 1.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [17] source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationreasoning

    SAF technologies with the most significant impact, high blend ratios, or novel compositions must undergo the Tiered Test Program.

    “Thus, SAF technologies with the most significant impact, high blend ratios, or novel compositions must undergo the Tiered Test Program.”
    Quote in the paperNot a substantial claim
    • Rests on an assumption: The Fast Track evaluation process has led to the approval of one fuel and production pathway annex in ASTM D7566 (Annex 7), with a maximum 10% blend limit.

  • May combine two claims.

    Premisecitation

    Based on years of NJFCP work, several predictive tools have been produced, and a shortlist of critical properties have been tabulated.

    “Based on years of this work with hundreds of collaborators and dozens of institutions, several predictive tools have been produced, and a shortlist of critical properties have been tabulated.”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [9]

      Not checked in the free run.

    • cites [10]

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing).

    Interpretationreasoning

    These constraints result in a difficult development target for new fuel producers.

    “These constraints result in a difficult development target for new fuel producers.”
    Quote in the paperNot a substantial claim
    • Rests on an assumption: Jet fuel specifications impose only a few limits on the fuel composition and ensure operability by an empirically evolved set of fuel property limits.

  • May combine two claims.

    Interpretationreasoning

    Candidate fuel 1 would not pass the thermal stability and water solubility tests due to the high alkene and oxygen content, so would not eclipse the ASTM D4054 evaluation process.

    “Moreover, such a fuel would not eclipse the ASTM D4054 evaluation process as it would not pass the thermal stability and water solubility tests due to the high alkene and oxygen content.”
    Quote in the paperSubstantial claim

  • Classified as probably not a substantial claim.

    Interpretationreasoning

    With low cost and low fuel volume methods, limited but useful information can be extracted.

    “With low cost and low fuel volume methods, limited but useful information can be extracted.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisecitation

    For ignition, physical and distillation properties dominate; fuel property dependence on LBO transitions from physical property dominance to chemical property dominance with increases in temperature and decreases in spray break-up time-scales.

    “For ignition, physical and distillation properties dominate [13], while fuel property dependence on LBO transitions from physical property dominance to chemical property dominance with increases in temperature and decreases in spray break-up time-scales [14].”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [13] source

      Not checked in the free run.

    • cites [14]

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Vozka and Kilaz performed a review of many older and some recent screening techniques for property determination that use small volumes of fuel.

    “Vozka and Kilaz [17] recently have performed a review of many older as well as some recent screening techniques for property determination that use small volumes of fuel.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [17] source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Sasol Fully Synthetic Jet Fuel is approved as a 100% synthetic drop-in by DefStan 91-091 but does not reduce carbon emissions.

    “(Sasol Fully Synthetic Jet Fuel is approved as a 100% synthetic drop-in by DefStan 91-091, but does not reduce carbon emissions [3].)”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [3]

      Not checked in the free run.

  • Classified as probably not a substantial claim. May combine two claims.

    Premisenone given

    Tier β eliminates concerns on the predictive aspects of Tier α and measures properties directly.

    “Tier β eliminates concerns on the predictive aspects of Tier α and measures properties directly.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisecitation

    The DLR model is a Gaussian Progress Regression algorithm that is trained on conventional and synthetic fuels.

    “The DLR model [30,31] is a Gaussian Progress Regression algorithm that is trained on conventional and synthetic fuels.”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [30]

      Not checked in the free run.

    • cites [31] source

      Not checked in the free run.

  • May combine two claims.

    Interpretationreasoning

    Correlations based on petroleum/distillate fuels may not be applicable to synthetic aviation fuels, and significant uncertainties can exist.

    “In general, correlations based on petroleum/distillate fuels may not be applicable to synthetic aviation fuels, and significant uncertainties can exist.”
    Quote in the paperSubstantial claim

  • Classified as probably not a substantial claim.

    Premisenone given

    Both tiers are outside of the ASTM evaluation process.

    “Both tiers are outside of the ASTM evaluation process”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisecitation

    There may be problems with surface tension, freeze point, permittivity, and heat of combustion (HOC) measurements, although, in many of these cases, there are problems both with the correlation method and the experimental measurement as well.

    “From time to time [29] there may be problems with surface tension, freeze point, permittivity, and heat of combustion (HOC) measurements, although, in many of these cases, there are problems both with the correlation method and the experimental measurement as well.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [29]

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S4 (based).

    Interpretationnone given

    The results of both tiers, assuming they are well documented, may be used to defer costs in Tier 1-4.

    “but the results, assuming they are well documented, may be used to defer costs in Tier 1-4.”
    Quote in the paperNot a substantial claim
    • The authors state this as an assumption: The results of both tiers are well documented.

  • Probably not a substantial claim: may not pass S4 (based).

    Interpretationnone given

    A set of priority property determinations have been identified, that if not satisfied, may cause significant delays and costs later in the evaluation process that precedes balloting to approve new components in the ASTM D7566 specification.

    “Specifically, a set of priority property determinations have been identified, that if not satisfied, may cause significant delays and costs later in the evaluation process that precedes balloting to approve new components in the ASTM D7566 specification.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Issues with other ASTM methods have been noted in detailed reports elsewhere.

    “Issues with other ASTM methods have been noted in detailed reports elsewhere [28,29].”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [28]

      Not checked in the free run.

    • cites [29]

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Ref. [25] implies the inclusion of non-petroleum fuels in their correlations (of mostly diesel fuels), but no data is provided.

    “Ref. [25] implies the inclusion of non-petroleum fuels in their correlations (of mostly diesel fuels), but no data is provided.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [25]

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationreasoning

    These issues many times stem from the unique compositions and selective isomeric structures of alternative fuels.

    “While not comprehensively state here, these issues many times stem from the unique compositions and selective isomeric structures of alternative fuels.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing). May combine two claims.

    Interpretationreasoning

    Candidate fuels with properties within or near the range of Jet A/ A-2 could be strong candidates, with other fuels potentially needing augmenting.

    “Candidate fuels with properties within or near the range of Jet A/ A-2 (green) could be strong candidates, with other fuels potentially needing augmenting.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    UD predictions leverage a database of 1226 molecules and their associated properties.

    “UD predictions [32] leverage a database of 1226 molecules and their associated properties.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [32] source

      Not checked in the free run.

  • May combine two claims.

    Premisenone given

    Separation is generally governed by distillation and polarity, and mass spectrometry (MS) identification cannot distinguish between two isomers of similar hydrocarbon group compositions.

    “Separation is generally governed by distillation and polarity, and mass spectrometry (MS) identification cannot distinguish between two isomers of similar hydrocarbon group compositions.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S4 (based).

    Interpretationnone given

    Traditional techniques, for which correlations were based solely on petroleum and distillate fuels, may contain bias that is not displayed in model accuracy metrics when applied to synthetic fuels.

    “However, it is argued that traditional techniques, for which correlations were based solely on petroleum and distillate fuels, may contain bias that is not displayed in model accuracy metrics when applied to synthetic fuels.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisereasoning

    This exercise minimizes property uncertainty and derisks a fuel production pathway but requires higher properties.

    “This exercise minimizes property uncertainty and derisks a fuel production pathway but requires higher properties.”
    Quote in the paperSubstantial claim
38 of 38

  • The paper relies on this without support.

    The Fast Track evaluation process has led to the approval of one fuel and production pathway annex in ASTM D7566 (Annex 7), with a maximum 10% blend limit.

    “With a maximum of a 10% blend limit, the Fast Track evaluation process has led to the approval of one fuel and production pathway annex in ASTM D7566 (Annex 7).”

  • The paper relies on this without support.

    Novel SAF candidates may require tests exceeding millions of dollars, tens of thousands of liters of fuel, years of testing, and sustained commitment of resources for fuel producers.

    “Novel SAF candidates may require tests exceeding millions of dollars in tests, tens of thousands of liters of fuel, years of testing, and sustained commitment of resources for fuel producers.”

  • The paper relies on this without support.

    Jet A/A-1 is the only energy source in current commercial aircraft.

    “Jet A/A-1 is the only energy source in current commercial aircraft.”

  • The paper relies on this without support.

    Jet A/A-1 performs other essential functions within the aircraft beyond chemical heat release.

    “Jet A/A-1 not only provides the energy source to propel the aircraft, but it also performs other essential functions within the aircraft beyond chemical heat release.”

  • The paper relies on this without support.

    Aviation fuel compositional and resulting properties can have a wide range of impacts on the handling, airframe, and engine.

    “An aviation fuel's compositional and resulting properties can have a wide range of impacts on the handling, airframe, and engine.”

  • The paper relies on this without support.

    Density impacts a diverse array of subprocesses and sub-component performances.

    “Density, for example, is noted to impact a diverse array of these subprocesses and sub-component performances.”

  • The paper relies on this without support.

    Variance in density impacts heat exchangers, pumps, gauging, fueling, and balance.

    “Variance in the density impacts heat exchangers, pumps, gauging, fueling, and balance.”

  • The paper relies on this without support.

    Early alternative fuel evaluations involved extensive testing, making the process arduous.

    “Early alternative fuel evaluations involved extensive testing (boxed metrics), making the process arduous.”

  • The paper relies on this without support.

    Operability and safety issues are key concerns that may not exhibit themselves until Tier 3 or 4 testing and after substantial costs in testing and fuel production have been expended.

    “Specifically, operability and safety issues are key concerns that may not exhibit themselves until Tier 3 or 4 testing and after substantial costs in testing and fuel production have been expended.”

  • The paper relies on this without support.

    FOM operability points (lean blowout, cold start, and altitude relight) represent the most critical and fuel sensitive metrics for qualification.

    “These FOM operability points (lean blowout [LBO], cold start, and altitude relight) represent the most critical and fuel sensitive metrics for qualification.”

  • The paper relies on this without support.

    Lowering aromatic content reduces soot emissions significantly but yields a material compatibility risk, i.e., o-ring shrinkage and fuel leakage.

    “For example, lowering the aromatic content reduces soot emissions significantly, but yields a material compatibility risk, i.e., oring shrinkage and fuel leakage.”

  • The paper relies on this without support.

    Approximately 400 L are required to initiate entry to the formal ASTM D4054 Tier 1 and 2 test process, even though test volumes for Tier 1 and Tier 2 may be as low as approximately 200 L.

    “For reference, ~400 L are required to initiate entry to the formal ASTM D4054 Tier 1 and 2 test process, even though test volumes for Tier 1 and Tier 2 may be as low as ~ 200 L.”

  • The paper relies on this without support.

    Jet fuel specifications impose only a few limits on the fuel composition and ensure operability by an empirically evolved set of fuel property limits.

    “However, jet fuel specifications impose only a few limits on the fuel composition and ensure operability by an empirically evolved set of fuel property limits.”

  • The paper relies on this without support.

    GCxGC has been extensively used to derive the composition of conventional jet fuels as well as synthetic fuel candidates.

    “In recent years, comprehensive two-dimensional Gas Chromatography (2D-GC or GCxGC) has been extensively used to derive the composition of conventional jet fuels as well as synthetic fuel candidates, sometimes referred to as hydrocarbon type analysis (HTA).”

  • The paper relies on this without support.

    2D-GC has become a pivotal part of the ASTM D4054 Fast Track process.

    “Furthermore, 2D-GC has become a pivotal part of the ASTM D4054 Fast Track process.”

  • The paper relies on this without support.

    The determination of fuel property values from small volumes of fuel samples is a research area that has long been investigated.

    “The determination of fuel property values from small volumes of fuel samples is a research area that has long been investigated.”

  • The paper relies on this without support.

    Many small-volume property determination methods have been adopted by ASTM over the years.

    “In fact, many such methods have been adopted by ASTM over the years.”

  • The paper relies on this without support.

    The variance across properties from SAF candidates can span the range of potential isomeric variances across all hydrocarbon types of the Jet A/A-1 distillation range.

    “Specifically, the variance across properties from SAF candidates can span the range of potential isomeric variances across all hydrocarbon types of the Jet A/A-1 distillation range.”

  • The paper relies on this without support.

    GCxGC methods cannot identify specific isomeric variances; at least one library at the University of Dayton (UD) has 1226 potential SAF molecules.

    “GCxGC methods cannot identify specific isomeric variances; at least one library at the University of Dayton (UD) has 1226 potential SAF molecules.”

  • The paper relies on this without support.

    Gevo ATJ and Amyris farnesane have been approved and are composed of only one or two components with very selective isomeric structures.

    “Already, several fuels have been approved that meet these criteria, Gevo ATJ and Amyris farnesane, as they are composed of only one or two components with very selective isomeric structures.”

  • The paper relies on this without support.

    SAFs offer advantages relative to conventional fuels as they mitigate climate change, may improve air quality, offer domestic economic opportunities, provide stable and diverse energy supply, and may ultimately improve aircraft operations with higher performance properties.

    “Sustainable Aviation Fuels (SAFs) offer advantages relative to conventional fuels as they mitigate climate change, may improve air quality, offer domestic economic opportunities (e.g., low-cost energy source), provide stable and diverse energy supply, and may ultimately improve aircraft operations with higherperformance properties.”

  • The paper relies on this without support.

    Production rates of currently approved SAF technologies can only meet a fraction of commercial airlines' market size.

    “Production rates of currently approved SAF technologies can only meet a fraction of commercial airlines's market size.”

  • The paper relies on this without support.

    SAF development and market penetration is arduous because SAFs are subject to tighter tolerances and more qualification hurdles than alternative fuels for ground transportation.

    “SAF's development and market penetration is arduous since SAFs are subject to tighter tolerances and more qualification hurdles than alternative fuels for ground transportation.”

  • The paper relies on this without support.

    Olefinic content, oxygenates, and other heteroatoms are deleterious to aviation fuel performance and safety metrics.

    “(These materials are deleterious to aviation fuel performance and safety metrics.)”

  • The authors state this as an assumption.

    The results of both tiers are well documented.

    “assuming they are well documented”

  • The paper relies on this without support.

    Production scale influences properties and trace contaminants.

    “As the production scale is known to influence properties and trace contaminants”
26 of 26

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

  • The ASTM D4054 certification process requires different fuel volumes in each tier and takes 3-5 years with a cost of at least $5 million on candidate fuel producers.

    “The comprehensive and meticulous method set by D4054 requires different fuel volumes in each different tier, and the 3-5 year process has a cost of at least $5 million on candidate fuel producers [37,38].”

    From Use of sustainable fuels in aviation: a review (2022) · cites this paper as [37]

Cites

Flagged first, then by citations

Research works printed but not linked: 4

  1. Sapp, 2018, Boeing 777 ecoDemonstrator arrives at FedEx hub flying on 100 % biofuel, Biofuels Dig
  2. Hadaller, 2006, World fuel sampling program, CRC Reports
  3. Thom MA. CRC Project No. AV-23-15/17: Review of Existing Test Methods Used for Aviation Jet Fuel and Additive Property Evaluations with Respect to Alternative Fuel Compositions 2018.
  4. Hall C, Rauch B, Bauder U, Le Clercq P, Aigner M. Application of Machine Learning algorithms for the prediction of fuel properties in comparison with state of the art physical models. 16th Int. Conf. Stability, Handl. Use Liq. Fuels, 2019.

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Related

Authors
Heyne, J., Rauch, B., Le Clercq, P., & Colket, M.
Affiliations
  • University of Dayton (US)
  • Deutsches Zentrum für Luft- und Raumfahrt e. V. (DLR) (DE)
  • RTX (United States) (US)
Corresponding author
Heyne, Joshua
ORCID
Venue
Fuel
Publisher
Elsevier BV
Published
2021-04
Volume
290
Pages
120004
ISSN
0016-2361 (ISSN-L)
DOI
10.1016/j.fuel.2020.120004
OpenAlex
W3116549204
Semantic Scholar
84c99f5ccebf56c87ef0722e30b5a4a992b5f027
Cited by
170
References
28
Citations by year
2026: 42 · 2025: 39 · 2024: 36 · 2023: 27 · 2022: 18 · 2021: 8
FWCI
4.93
Type
journal article
Language
en
Open access
Licence
Locations
  • Fuel (publishedVersion, cc-by)
  • elib (German Aerospace Center) (acceptedVersion)
  • elib (German Aerospace Center) (submittedVersion)
  • ROSA P (submittedVersion, cc-by)
Funders
  • Horizon 2020 (723525)
  • Air Force Research Laboratory
  • Federal Aviation Administration (13-CAJFE-UD-18)
Topics
  • Physical Sciences › Environmental Science › Global and Planetary Change › Advanced Aircraft Design and Technologies
  • Physical Sciences › Engineering › Computational Mechanics › Heat transfer and supercritical fluids
  • Physical Sciences › Chemical Engineering › Fluid Flow and Transfer Processes › Advanced Combustion Engine Technologies
Keywords
sustainable aviation fuel, prescreening, fuel properties, fuel certification

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Claims read by deepseek-v4.1-flash under definition version 3 (extract-v3) on 2026-10-10.

Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-10-10.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

What counts as a claim ›How we measure confidence ›How we check this ›

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