Compatibility of Fuel System Elastomers with Bio-Blendstock Fuel Candidates Using Hansen Solubility Analysis

The compatibility of key fuel system infrastructure elastomers with promising bio-blendstock fuel candidates was examined using Hansen solubility analysis. Thirty-four candidate fuels were evaluated in this study including multiple alcohols, esters, ethers, ketones, alkenes and one alkane. These compounds were evaluated as neat molecules and as blends with the gasoline surrogate, dodecane and a mix of dodecane and 10% ethanol (E10D). The elastomer materials were fluorocarbon, acrylonitrile butadiene rubber (NBR), styrene butadiene (SBR), neoprene, polyurethane and silicone. These materials have been rigorously studied with other fuel types, and their measured volume change results were found to correspond well with their predicted solubility levels. The alcohols showed probable compatibility with fluorocarbon and polyurethane, but are not likely to be compatible at low blend levels with NBR and SBR. Low and mid-range blends are also considered incompatible with silicone, as are mid-range blends with neoprene. The alkane fuel candidate is likely compatible with fluorocarbon, polyurethane, NBR and SBR at most blend levels, but low to mid-range blends are not likely compatible with silicone. Neoprene showed compatibility only with mid-range blends of the alkane. The alkene and aromatics exhibited similar compatibility. They showed good compatibility with fluorocarbon, neoprene and polyurethane, but not with silicone, NBR, and SBR. For the esters, compatibility varied depending on the ester type. Generally, these fuels were compatible with fluorocarbon and polyurethane, but not with silicone. Low blend levels are likely to be compatible with neoprene, but considerable uncertainty is noted for NBR and SBR. Ethers were generally compatible with fluorocarbon and at low blend levels with neoprene and polyurethane. They were most incompatible with silicone, NBR, and SBR. The ketones were the one fuel type that showed some incompatibility with fluorocarbon, especially at high blend levels. Incompatibilities were also noted for silicone, neoprene and polyurethane. However, ketones are likely compatible with NBR and SBR at high blend levels.Cross Reference: