Compatibility Assessment of Isobutanol-Gasoline Fuel Blends with Fueling Infrastructure Materials

Mike Kass, Tim Theiss, Chris Janke, Steve Pawel, and Jeff Thomson Oak Ridge National Laboratory

Jim Baustian and Les Wolf Butamax Advanced Biofuels, LLC

Wolf Koch Technology Resources International, Inc.

24th National Tanks Conference & Expo Denver, CO September 17, 2013 Isobutanol is of interest since it provides a pathway for meeting the 36BGPY RFS requirement by allowing greater biofuel usage than can be achieved by ethanol alone

• Isobutanol can be produced Property Isobutanol Ethanol Gasoline from existing ethanol production plants via retrofit Oxygen (wt.%) 21.6 34.7 ---- Blending ratio to achieve technology 16 10 ---- 3.7 wt.% oxygen, (%) • Isobutanol has a much Heating Value relative to 84 66 100 higher energy density than Gasoline (%) ethanol Blending octane 105 122 87

• Water has a relatively low Polarity Index 4 5.2 <2.4 solubility with isobutanol Solubility in water (mL/100mL) 8.7 miscible <0.01 • Isobutanol has a slightly lower polarity index than ethanol suggesting reduced corrosion potential

Isobutanol Ethanol

2 Presentation name Goal: To provide a data set of material properties for use to the fueling infrastructure community

• Prior test fuels included Fuel C, CE10a, CE17a, and Metals & Alloys Elastomers Plastics CE25a, CE50a and CE85a 304 stainless steel Fluorocarbons (2) HDPE • Polymer specimens measured for change in volume, mass, hardness and DMA 1020 carbon steel NBRs (6) Polypropylene • Specimens exposed to test fuel liquid and vapor 1100 aluminum Silicone rubber POM (2) phase regions Cartridge brass Fluorosilicone Nylon (4) • Ethanol compatibility effort funded by DOE Phosphor bronze Neoprene PVDF Nickel 201 SBR PTFE (Teflon) Terne-plated steel Polyurethane PPS Galvanized steel Rubberized cork (2) PET (2)

Cr-plated brass PBT Cr-plated steel PTU Ni-plated aluminum Isophthalic polyester resin (2-types) Ni-plated steel Terephthalic polyester resin Novolac vinyl ester resin Epoxy resins (2-types and 2-cures)

3 Presentation name Many of the materials investigated in this study have direct use in fuel storage and delivery systems

Fuel Dispenser

Flow limiter (Al, steel) Tanker Truck Pump Line Breakaway valve (nylon, HDPE, fluorocarbon, NBR, fluorosilicone) Flexible connector Adapter (SS, fluorocarbon, NBR) (Bronze, Al, polyurethane, Nozzle (nylon, Al, fluorocarbon, nylon, SS, NBR) Silicone rubber, NBR, fluorosilicone, HDPE) Spill container Emergency Shear Valve Protector (Iron, steel, brass, SS, Swivel (SS, fluorocarbon, NBR) (Al, fluorosilicone, nylon) Pressure Vacuum Vent PTFE,Teflon, polyurethane) (polypropylene, SS, Al) Pump (steel, aluminum) Hose (NBR) Jack Screw (see adapter)

Piping (nylon, PVDF, PPS, Vapor Line Shear Valve polyester resins) VAPOR (Iron, fluorocarbon, Overfill protection polyurethane) Extractor fitting (iron, valve (see adapter) polyurethane, Zn alloy) Ball float vent valve (steel, SS) LIQUID Underground Tank walls (Steel, thermosetting Fuel Storage Tank Tank Bottom Protector (Al, SS) plastic resins)

Some materials may have been missed

4 Presentation name Ethanol-blend test fuels were formulated based on SAE J1681, which also served as the basis for the isobutanol-blend test fuels

• Ref Fuel C is a test fuel representing gasoline. It is a mix of 50% toluene and 50% isooctane Component Mass • An aggressive isobutanol was formulated based on the constituents and molar concentrations of (g) “aggressive ethanol” Reagent grade isobutanol 797.7 • Oxygen equivalency: De-ionized water 7.987 – CE10a corresponds to CiBu16a Sodium chloride 0.004 – CE17a corresponds to CiBu24a Sulfuric acid 0.021 • CE17a was chosen to represent E15 Isobutyric acid 0.088

Test Fuel Formulation Material Type Fuel C CE10a CE17a CE25a CiBu16a CiBu24a Elastomers X X X X X X Metals X X X X X X Plastics X X X X

5 Presentation name Presented results highlight the volume and hardness change (from the original baseline condition) and the glass-to-rubber transition temperature for the elastomer and plastic materials

Wetted Property Measurement Indicates: – Extent of solubility – Extrusion potential (elastomers) – Extent of softening – Potential residual stress (plastics) Dried Property Measurement Indicates: – Dissolution (removal of one or more components) – Embrittlement (removal of plasticizer components) – Fluid retention

6 Presentation name Elastomer Types and Applications

Materials Applications

• Fluorocarbon (2 types) High performance seals • Fluorosilicone (o-rings, gaskets, etc.) Seals (o-rings, gaskets, etc.) • NBRs (6-types) Hoses (all applications)

• Neoprene Seals (gaskets, etc.) • Polyurethane Coatings

• SBR ? • Silicone Seals (gaskets, etc.)

7 Presentation name Volume Swell Results for Elastomers: • Fluoroelastomers swelled the least; while SBR and silicone swelled the highest • The addition of ethanol or isobutanol was observed to increase swell, and in most cases, isobutanol produced slightly lower swelling than equivalent levels of ethanol

Isobutanol had no added effect for SBR and silicone.

NBRs swelled15-25% with Fuel C and an additional 10% with the oxygenated test fuels

8 Presentation name Wet Hardness Results for Elastomers: The swelling was accompanied by a reduction in hardness (softening). In general, the extent of softening corresponded to the level of swell.

Polyurethane was softened by ethanol and isobutanol

9 Presentation name Dried Volume Results for Elastomers: After drying for 20h at 60oC, shrinkage was observed for the NBRs, neoprene, SBR, and polyurethane (shrinkage is indicative of extraction) Key Observations:

• Fluorocarbons maintained a small level of expansion • Shrinkage observed for NBRs, neoprene, and SBR was primarily caused by Fuel C • Polyurethane was the elastomer most affected by the alcohol components (especially ethanol) • Fluorosilicone and silicone returned to their starting geometries

10 Presentation name Dried Hardness Results for Elastomers: The change in hardness results after drying showed that the hardness was increased (embrittled) for the NBRs and neoprene

Key Observations:

• Fluorocarbons remained softened • Fluorosilicone and silicone returned to their starting values • Polyurethane remained softened by the alcohols • In general the added isobutanol performed similar to ethanol • SBR showed more sensitivity to isobutanol than ethanol

11 Presentation name Glass to rubber transition temperature results for the elastomers showed small changes from original unexposed baseline condition

12 Presentation name Plastic Types and Applications

Materials Applications • PPS • PET (Mylar) Permeation barriers for • PTFE (Teflon) plastic piping • PVDF • Nylon 12 • Nylon 6 Structural support and • Nylon 6,6 outer walls of flexible • Nylon 11 (vegetable oil derived) plastic piping • HDPE • Vinyl ester resin Resins for fiberglass • Terephthalic polyester resin tanks and piping

13 Presentation name Volume Swell Results for Plastics:

• Barrier materials exhibited the lowest level of swell • The results for the nylons varied according to type. Nylon 12 expanded 7-10% with exposure to the oxygenated fuels. Nylon 6 and Nylon 6,6 exhibited only slight swell with the isobutanol test fuels • Terephthalic Nylon 11 swelled 5% with polyester resin Fuel C and 18% with CE25a exhibited 7% swelling with Fuel C and ~25%with exposure to the oxygenated fuel compositions • Compared to terephthalic polyester, the vinyl ester resin exhibited better compatibility to the test fuels, except for CE25a

14 Presentation name Wet Hardness Results for Plastics: For many plastics, the hardness results did not change much. The most affected were Nylon 11 and terephthalic polyester

15 Presentation name Dried Volume Results for Plastics: When dried many of the plastics exhibited volume expansion (compared to baseline)

• Barrier materials and HDPE returned to their original volumes • Nylons 6 and 6,6 were not affected by Fuel C and isobutanol, but they did show expansion with CE25a • After drying, the resins remained swollen following exposure to CE25a, CiBu16a and CiBu24a Nylon 12 experienced • Of the two resins shrinkage studied, the vinyl ester resin exhibited better compatibility to the test fuels, except for CE25a

16 Presentation name Dried Hardness Results for Plastics: Observed softening corresponds to the level of retained fuel (or volume increase)

Deviation from baseline is low

17 Presentation name Glass Transition Temperature Results for Plastics: These results indicate that some structural change had occurred for PET, nylon, and resins with exposure to one or more of the test fuels

PET showed no accompanying changes in volume and hardness

18 Presentation name Summary of Key Findings

• Of the two classes of polymers studies, elastomers usually exhibited higher levels of swelling than plastics – Much of this volume expansion can be attributed to Fuel C, however, the NBRs and neoprene showed additional expansion with the fuels containing ethanol or isobutanol • In general, after drying, the elastomers experienced some level of shrinkage. – The NBRs and neoprene exhibited a measureable hardness increase (embrittlement) indicating that the plascticer components may have been extracted by the test fuels. – The fluorosilicone and silicone specimens returned to their original volumes – Polyurethane was structurally degraded • The plastics exhibited a wide range of swelling – The permeation barriers swelled the least – The results for the nylons varied according to type – The resins swelled over 20% with CE25a • After drying the plastics remained swollen (except for Nylon 12 which lost volume) – The resins had exhibited higher volume expansion with exposure to the oxygenated test fuels • In general the addition of ethanol and isobutanol produced similar results. In most cases the level of swell and softening was less with isobutanol compared to oxygen equivalent levels of ethanol. • Structural changes may exist even if the hardness and volume are not affected

19 Presentation name Thank You for Your Attention!

• Further information can be found in the following report:

Compatibility Study for Plastic, Elastomeric, and Metallic Fueling Infrastructure Materials Exposed to Aggressive Formulations of Isobutanol- blended Gasoline

http://info.ornl.gov/sites/publications/Files/Pub44488.pdf

www.osti.gov/servlets/purl/1092302/

• Future work is being planned. If there is a material that you think should be included, please let us know and we’ll add it to the matrix

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