2014-07-25 DRDC-RDDC-2014-L95

Distribution List

Scientific Letter

Alternative fuels for use as potential ‘drop-in’ fuels for naval applications: critical analysis

Synopsis In anticipation of incorporation of alternative fuel components in developing allied naval fuel standards, Defence Research and Development Canada (DRDC) conducted a scientific scoping study of industrial and allied partner alternative fuel R&D efforts and fuel use [Reference 1]. This scoping study arose from and was developed through consultation with Directorate of Naval Strategy (DNS 3-2), the Technical Authority for naval fuels at the Directorate of Naval Platform Support (DNPS 2-4-7) and the alternative fuels strategic advisor for the policy authority for fuels at the Directorate of Fuels & Lubricants (DF&L 7) [Reference 2].

‘Drop-in’ fuels are fuels that may be integrated without major modification to existing fuel infrastructure (e.g., storage tanks, fuelling systems and engines). The miscibility and similar properties (e.g., energy density, viscosity and lubricity) of most renewable and synthetic fuels make them potential substitutes for (or as blends with) conventional fuels — and the focus for this study.

The goals for the DRDC scoping study were to [Reference 3]:

evaluate mature ‘drop-in’ alternative fuels against a list of integration criteria; identify and describe the potential consequences related to use of specific mature

alternative fuels on naval fuel infrastructure; and identify gaps in the technical data required for more comprehensive analysis.

The scientific scoping study does not constitute part of any Canadian Armed Forces (CAF) or Department of National Defence (DND) requirement or plan to acquire or develop a scientific capability in this Science and Technology (S&T) area. This study was employed by DRDC to better enable the provision of neutral, timely and evidence-based S&T advice to the CAF and DND if and when required.

This report is a summary of the principal findings and accurately summarizes the ‘drop-in’ suitability of current alternative fuels that are available as a full or partial (blend) replacement in naval assets including, helicopter engines, ship engines and ship generators.

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Background NATO navies currently rely on two fuels, jet propellant JP-5 and naval distillate F-76 fuels (F-75 has some limited application). JP-5 is used for helicopters and is a unique military fuel that is kerosene-based and with a higher minimum flashpoint (60 °C) than commercial diesel and gasoline fuels. Naval distillate F-76 is the primary propulsion fuel for naval ships. It differs from commercial fuels in that it is made from straight distillate, typically includes stability additives and has a minimum flashpoint of 60 °C. The NATO naval distillate standard STANAG 1385 is now under revision to allow fuel to be manufactured from distillates of crude oil or from distillate blends of crude oil and synthetic fuels derived from biomass [Reference 4].

A summary of the open literature had shown that the majority of R&D efforts and application trials for alternative fuels were for land-based applications, particularly for blending with road diesel and gasoline. While some research for aeronautical usage was available, marine applications were uncommon. The US Air Force (USAF) and American Society for Testing and Materials (ASTM) have approved blending of specific alternative synthetic fuels for use as aviation turbine fuels [Reference 5]. According to ASTM standard D7566-11a, Fischer-Tropsch hydroprocessed Synthetic Paraffinic Kerosene (FT-SPK) and Synthetic Paraffinic Kerosene from Hydroprocessed Esters and Fatty Acid (SPK-HEFA) may be blended with Jet propellant A or A-1 up to 50% by volume. This standard was recently updated (ASTM D7566-14A) to relect acceptance for blending with renewable Synthesized Iso-Paraffinic fuels [Reference 5].

DND and the Royal Canadian Air Force (RCAF) have made significant advances in their program for certification of alternative fuels for ‘drop-in’ use on RCAF platforms — the Royal Canadian Navy (RCN) should emulate this process. This was largely due to the proliferation of international R&D programs on alternative fuels with aeronautical focus. This data is accessible through international partner collaborations with The Technical Cooperation Panel (TTCP), the America, Britain, Canada, Australia, New Zealand (ABCANZ) treaty and through direct contact with interested United States Navy (USN) personnel.

In Canada, the Canadian General Standards Board (CGSB) has recently (2013) adapted standards for aviation turbine fuels Grades Jet A and A-1 (CGSB 3.23-2013) and Military Grades F-34 and F-44 (CGSB 3.24-2013) to include the use of FT-SPK and SPK-HEFA as a ‘drop-in’ alternative fuels [Reference 6 and 7]. The CGSB had some concern that SPK-HEFA due the concentration of gum and fatty-acid methyl esters. Engine testing at the National Research Council (NRC) Gas Turbine Laboratory had demonstrated that a synthetic jet fuel made from blended 50% SPK-HEFA and 50% JP-8 showed no adverse effects on engine durability, performance or safety when used in a Rolls-Royce Allison T56 engine [Reference 8].

The USN has recently completed certification of JP-5 and F-76 fuels that are blended with alternative fuels in [Reference 2]. The USN is anticipating delivery of blended 10% alternative —90% petroleum based JP-5 fuel for east coast operations by 1 April 2015. It is anticipated that the 10% fuel will enter the supply chain, but will be mixed with existing fuels so that the proportion of alternative fuels would take time to increase to 10% of the entire fuel supply. This is expected to have a direct impact on those countries that accept JP-5 and F-76 naval fuels from USN ports and supply ships. Currently the RCN uses NATO F-76 for shipboard propulsion and JP-5 for associated aircraft (helicopters).

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Statement of results DRDC had identified and evaluated alternative fuels for their potential for use as a blend with gasoline or diesel [Reference 3]. As part of this preliminary analysis, methanol, ethanol and biodiesel were found to be unsuitable for blending with diesel fuels and were not subjected to further analysis (Table 1) in this study.

Table 1: Preliminary analysis of alternative fuel.

DRDC conducted an analysis of the technical data for the seven remaining fuel types. Two separate contractors were used to provide independent comprehensive examinations of public domain literature for consequences related to the introduction and continued use of mature ‘drop-in’ liquid alternative fuels on naval fuel infrastructure [Reference 3]. Technical data was enriched thorough collaboration with allied partner countries via international technical cooperation panels.

According to the information available at the time of the study, Dimethyl Ether (DME), Pyrolysis-based fuel and Gas-to-liquid (GTL) diesel were found to have a low Manufacturing Readiness Level (MRL) and low Technical Readiness Level (TRL). DME and GTL were not considered ‘drop-in’ candidates. These fuels required more technical data to make an accurate assessment and should be regulated to a watch list for future changes to MRL and TRL. While SPK-HEFA had significant potential, more technical information was required prior to an accurate assessment. DRDC will contact USN for up-to-date technical information on blended SPK-HEFA (and FT-SPK) that they are in the process of certifying [Reference 2].

Gasoline replacements Preliminary Analysis MRL TRL for Naval Use

Suitable 'Drop-in' Fuel

Methanol/Ethanol Safety issue (low flash point), not recommended for military use.

10 Not appropriate

No

Biobutanol No significant issues, recommended and readily available.

7-8 5-6 Yes, evaluation required

Dimethyl Ether (DME) No significant issues cited, but limited technical data. More development required.

4-5 3-4 Limited technical data, watch

Pyrolysis Fuel Current form is corrosive, more development required.

2-3 2-3 Limited technical data, watch

Diesel replacements Preliminary Analysis MRL TRL for Marine Use

Status

Biodiesel - FAME based Hydroscopic and biodegradable, not recommended for marine environments.Naval application would require additives.

10 Not appropriate

No

Hydrogenation-Derived Renewable Diesel (HDRD)

No significant issues, recommended and readily available

9 9 Yes, evaluation required

Fischer-Tropsch hydroprocessed Synthetic Paraffinic Kerosene (FT-SPK)or Fischer-Tropsch Gas-to-Liquid (GTL) diesel

No significant issues, recommended, readily available and in use as aviation fuel

7-8 8-9 Yes, evaluation required

Synthetic Paraffinic Kerosene (SPK) from Hydroprocessed Esters and Fatty Acid (HEFA)or Hydrogenated Renewable Jet (HRJ)

No significant issues cited, but limited technical data. More development required.

6-7 8-9 Yes, more technical data required

Other Gas-to-Liguid (GTL) Diesels No significant issues cited, but limited technical data. More development required.

4-5 4-5 Limited technical data, watch

Notes: MRL is Manufacturing Readiness Level , with va lues from prel iminary research (1) to exceeding cost level , manufacturing and performance goals (10).TRL i s Technica l Readiness Level , with va lues relative to marine appl ication that range from bas ic principles (1) to platform proven (9).

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The following fuels did not show significant compatibility issues with the engine and fuel infrastructure of the test platforms (used in each of the studies reviewed):

1. Fischer-Tropsch hydroprocessed Synthetic Paraffinic Kerosene (FT-SPK), as a JP-5 replacement;

2. Hydrogenation-Derived Renewable Diesel (HDRD), as an F-76 replacement; and 3. Biobutanol, as a gasoline replacement.

These three promising alternative fuels were subjected to a rigorous comprehensive analysis with respect to properties and integration criteria for ‘drop-in’ naval use [Reference 9 and 10]. As part of this comprehensive analysis, DRDC created an evaluation matrix to display specific ‘drop-in’ alternative fuel candidates against important properties and integration criteria [Reference 11]. The current iteration of the matrix (Table 2) represented DRDC’s analysis of the technical data available through the two contracts and a comprehensive review of the open literature. This was augmented with data made available through international partner collaborations through TTCP and ABCANZ.

The evaluation matrix was used to assess Biobutanol, HDRD, FT-SPK and SPK-HEFA against specific ’drop-in’ criteria [Reference 10] and relative to F-76 and/or JP-5 standards — for potential blending. SPK-HEFA was omitted from the evaluation due to a broad lack of technical information at this time that would have biased the results. The scoring for Biobutanol, HDRD and FT-SPK reflected the existing technical information that was available during this study.

Biobutanol was found to have a high cost, low TRL level and was not yet considered a direct diesel replacement at this time [Reference 10]. Biobutanol was only useful for blending with gasoline for use in spark-ignition engines until processes were developed to ensure that it will adhere to F-76 and JP-5 specifications [Reference 9]. The US Naval Air Warfare Center Weapons Division developed and is scaling up a process to convert n-biobutanol to bio-kerosene and bio-diesel fuels [Reference 12]. Biobutanol should be relegated to the technical watch list (with SPK-HEFA) for future evaluation as a potential ‘drop-in’ replacement for F-76 or JP-5.

FT-SPK and HDRD were found to be suitable for use in marine environments and had scored well in comparison to F-76 and JP-5 naval fuels, respectively [Reference 9 and 10]. FT-SPK is also suitable for blending with F-76 as JP-5 fuels are considered a suitable, but expensive, replacement fuel for F-76. F-76 is not a suitable replacement for JP-5.

Although, there were concerns that the majority of the test platforms were modern engines that employ polymers that are compatible with most alternative fuels. The lack of aromatics in alternative fuels has been proven to be an issue with older seal and gasket materials. It is advisable to ensure that all seal and gasket material are comprised of compatible materials (nitriles, fluorocarbons and fluorosilicones).

Properties, criteria and weighting factors reflected DRDC’s perception of RCN requirements and priorities. An electronic file of the matrix will be made available for periodic update as technical information becomes available and priorities change. The technical information gaps in Table 2 (red italics) reflected potential areas for collaboration with allies and for Canadian R&D efforts.

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Table 2: Comprehensive analysis of ‘drop-in’ fuels against various integration criteria.

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In general, effort is needed to acquire technical data to fill in the gaps related:

1. metallic and non-metallic materials incompatibility that includes both physical (e.g., density, dissolved gas, interfacial tension) and chemical (e.g., lubricant dilution, corrosion, degradation) interactions;

2. storage related phenomena (e.g., hydroscopic tendencies, bio fouling, chemistry), affected by time and temperature;

3. fire suppression (e.g., flame spread, firefighting, combustion temperatures); and 4. testing on engines or engine components that are specific to CAF platforms.

Discussion of results Biobutanol, HDRD, FT-SPK and SPK-HEFA are second generation alternative fuels that have the most potential of the ‘drop-in’ candidates. While SPK-HEFA and Biobutanol were found to have significant potential as F-76 and JP-5 replacements, they should be relegated to the technical watch list. Notwithstanding the technical information gaps (that need to be addressed), HDRD and FT-SPK fuels scored well relative to available data, and represented sound options for further consideration as ‘drop-in’ fuels and further laboratory testing and laboratory-based diesel engine trials.

According to the information available at the time of the study, there were no compatibility issues between FT-SPK and HDRD alternative fuels, and the engine and fuel system materials of the test platforms examined in this study [Reference 9 and 10]. Unfortunately, the majority of test platforms were modern systems and there was some concern that the lack of aromatics in the alternative fuels could prove to be an issue with older seal and gasket materials.

HDRD suffered from high production costs, lower energy content and was lacking a significant amount of technical information. The USN had trialed HDRD versions of F-76 (HRD-76) and JP-5 (HRJ-5) that meet the F-76 and JP-5 specifications. They have only been used up to 50/50 blends with existing F-76 and JP-5 fuel to date [Reference 4].

This analysis and the certification by ASTM and CGSB, led DRDC to consider FT-SPK as the foremost candidate for ‘drop-in’ alternative fuel status — when blended with regular fossil fuels. FT-SPK undergoes a rigorous synthesis process (include hydro-treating, hydro-cracking, or hydro-isomerization) to produce a synthetic blend of paraffins and with few contaminants that were often present in other biofuels. The chemistry of the specific paraffinic molecules (e.g.,, carbon numbers of iso-paraffins, cyclo-paraffins and paraffins) had been known to have a significant effect on the flow properties and engine performance. Modifying the distillation process to remove lighter elements, would produce a fuel with heavier, more complex paraffins that would increase flash point, improve cold-flow characteristics, and improve energy density.

Extremely low concentrations of sulfur, aromatics and other toxins (that vary with feedstock and processing) resulted in decreased soot in the combustor which decreases engine temperatures and produces less exhaust particulates and gases. Estimates vary, but reductions in hydrocarbons (> 20%), carbon monoxide (>40%), NOx, particulate matter (>30%), SOx (>99%) were reported in the open literature [Reference 9 and 10].

FT-SPK fuels appear to have similar properties to JP-5 except that there were concerns with:

1. zero aromatics. Blending with conventional fuels was required to provide an appropriate concentration of aromatics to ensure elastomer swell — compatible materials (nitriles, fluorocarbons and fluorosilicones) are readily available. Neoprene was identified as slightly incompatible, while natural rubber, styrene/butadiene, butyl rubber, ethylene/polyethylene

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and silicone were incompatible with SPK. Polyurethane was found to be severely incompatible (it softens as it dries after exposure to SPK);

2. poor cold-flow characteristics; need to study effect on specific components; 3. density, viscosity, lubricity; need to study effect on specific components; 4. lack of technical data on material incompatibilities (e.g., chemical bonding, dissolved gases

and storage); and 5. lack of technical data on fire suppression (e.g., flame spread) and storage (especially in

contact with seawater).

The above effects may be reduced with stipulations in new CGSB specifications for proper blending with conventional fuels. For cold weather operation, it is advisable to consider devising a winter blend or latitude-specific blend comprised of heavier paraffins. For marine application, specific additives, including lubricity additives, are required. Additives could also ensure that fuel blends would not adversely impact turbine engine safety, durability, or performance — especially for aging infrastructure.

Given that the USN has recently certified FT-SPK, HDRD and SPK-HEFA for naval use, materials compatibility, full scale diesel engine and boiler testing should be nearing completion [Reference 13]. The USN has also stated that they will work with other countries interested in conducting tests as part of their alternative fuel evaluation. DRDC plans to request technical data related to fire suppression, metallic and non-metallic materials incompatibility, storage.

Conclusion This document provides a summary of the DRDC scientific scoping study of industrial and allied partner alternative fuel use and research. This, together with the companion contract reports [Reference 9 and 10], provides neutral, evidence-based S&T advice on the potential impact of alternative fuels on naval vessel operation.

DME, Pyrolysis-based fuel and GTL diesel need to be monitored for additional technical data and changes to MRL and TRL. More technical information is required before SPK-HEFA, HDRD and Biobutanol blends can be considered suitable for ‘drop-in’ replacement for F-76 and JP-5 fuels. They are relegated to the technical watch list for monitoring as potential ‘drop-in’ replacements for F-76 and JP-5 fuels.

FT-SPK was found to have the greatest potential as a ‘drop-in’ fuel. FT-SPK and SPK-HEFA are currently being produced in sufficient quantities for trial purposes, and, at the time of writing of this report, the USN was only trialling them as blended fuels, not as pure F-76 or JP-5 alternatives. The USN has offered to supply Canada with alternative fuels in exchange for experimental technical data generated during testing. The USN is also capable of providing data on FT-SPK and SPK-HEFA blends in F-76 and/or JP5, as they will start procurement of these fuels in early 2015

There are still technical gaps in the assessment matrix that need to be addressed. There needs to be better understanding of the impact of varying fuel stock (chemistry) and/or fuel processing on resultant fuel properties and corresponding effects on engine operations, reliability and life. Research must also explore the potential long-term impact of alternative fuels on the engine materials and components.

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Recommendations The USN should be contacted for up-to-date technical information on SPK-HEFA, FT-SPK and HDRD as they have approved programs for certification of blended fuels. The USN has the capacity to trial and certify alternative fuels.

It is recommended that laboratory and engine testing be conducted to ensure there are no material compatibility issues. DRDC should consider the USN offer for supply of FT-SPK and SPK-HEFA for fuel chemistry analysis, material property verification and small scale incompatibility testing.

NRC has the facilities for and has expressed interest in testing alternative fuels on available diesel engines. It is also recommended that NRC consider the offer by the USN for the supply alternative fuels for the purpose of conducting large scale engine testing.

Before introducing any of the alternative fuel blends into general marine/military use by the CAF, it is recommended that the fuel should be shown to be equivalent to current F-76 and JP-5 specifications.

This document is believed to accurately summarize the ‘drop-in’ readiness of current alternative fuels available for consideration in naval applications. Questions, comments or suggestions are welcome and should be directed to the Scientific Authority, Dr. Shannon Farrell at 902-427-3437 or at shannon.farrell@forces.gc.ca.

Prepared by: Shannon P. Farrell, DRDC Atlantic Research Centre, Dockyard Laboratory

References [1] S.P. Farrell, “Assessing alternative fuels for use as potential ‘drop-in’ fuels for naval

applications: plan for a scoping study”, DRDC Atlantic File #19100-1(DLA) to DNS 3-2 (LCdr R. Snook) and MSTC (LCdr D Woodward), June 2013, 11 pages.

[2] S.P. Farrell, “Discussion on Certification of Alternative Fuels” (Protected B), minutes of telecon between RCN and USN contacts, August 2013.

[3] S.P. Farrell, “Assessment of alternative fuels and consequences for usage on naval vessels”, DRDC Contract #W7707-145682 Statement of Requirement, 2013.

[4] Guide Specification (Minimum Quality Standards) for Naval Distillate Fuels (F-75 and F-76), NATO Standardization Agreement, STANAG1385, October 2013.

[5] “Standard Specification for Aviation Turbine Fuel Containing Synthesized Hydrocarbons, ASTM D7566-14a, ASTM International, 2014.

[6] Aviation Turbine Fuel (Grades Jet A and Jet A-1), CAN/CGSB-3.23-2013 (Amended).

[7] Aviation Turbine Fuel (Military Grades F-34 and F-44), CAN/CGSB-3.24-2013 (Ammended).

[8] W. Chishty et al, "Evaluation of T-56 Engine Performance and Emissions using Camelina based HEFA Fuel Blend," NRC Canada, File #LTRGTL-2011-0085, March 2012.

[9] R. Harding, W. Remley (Alion Science and Technology), “Assessment of alternative fuels and consequences for usage on naval platforms: Synopsis A”, Defence Research and Development Canada Contract Report C14-0328-1242, April 2014.

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[10] R. Clayton, D. Senik, S. Porter, B. Saville (Doyletech Corporation), “Assessment of alternative fuels and consequences for usage on naval vessels: Synopsis B”, Defence Research and Development Canada Contract Report C14-0328-1243, April 2014.

[11] S.P. Farrell, “Performance evaluation criteria”, email correspondence with Alion Science and Technology and Doyletech Corporation on draft reports, December 2012.

[12] R. Wilson (Cobalt Technologies), “Butanol Q&A” http://www.consumerenergyreport.com /2011/02/14/butanol-qa-with-cobalt-technologies-ceo-rick-wilson/”, Feb. 14, 2011.

[13] “US Position Statements”, minutes of MMIEA R-ABCANZ 09-04 Naval Fuels and Lubricants 2012 Meeting in Wellington, New Zealand, 2012.

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Distribution list NDHQ/DGSTAN/DSTN 4 Mr. B. Staples NDHQ/DGNFD/DNS 3-2 LCdr. R. Snook NDHQ/DGMEPM/DNPS 2-4 Dr. J. Huang NDHQ/DGMEPM/DNPS 3-4 Mr. B. Cox NDHQ/DGMEPM/DNPS 2-

Mrs. L. Onu

NDHQ/DMSSC/DFL 7 Dr. R. Voicu NDHQ/DMSSC/DFL 4 Mrs. N. Gaudet NDHQ/QETE 3-3 Mr. P. Poitras NRC/Aerospace Mr. P. Canteenwalla DRDC-ARC/CSci (*Acting) Dr. L. Cheng DRDC-ARC/DLA/SH Mr. G. Fisher DRDC-ARC/DLA/GL/MIA Dr. R. Underhill DRDC-ARC/DLP/GL/PC Dr. T. Huber DRDC-ARC/DLA/DS Dr. S. Farrell

This Scientific Letter is a publication of Defence Research and Development Canada. The reported results, their interpretation, and any opinions expressed therein, remain those of the authors and do not necessarily represent, or otherwise reflect, any official opinion or position of the Canadian Armed Forces (CAF), Department of National Defence (DND), or the Government of Canada.

© Her Majesty the Queen in Right of Canada, as represented by the Minister of National Defence, 2014

© Sa Majesté la Reine (en droit du Canada), telle que représentée par le ministre de la Défense nationale, 2014

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