15-21: Results of ORNL Biofuels Compatibility Studies with Infrastructure Materials

The Energy Independence and Security Act of 2007 calls on the nation to significantly increase its use of renewable fuels to meet its transportation energy needs.  Multiple biofuels, including various blends of ethanol, biodiesel, and other advanced biofuels are being considered and are likely to be used to meet this mandate.  The impact of these various biofuels on the fueling infrastructure is not known and could be problematic. 

A screening technique has been developed by Oak Ridge National Laboratory (ORNL) to assess the compatibility of biofuels with typical infrastructure materials.  A large number of metallic, elastomers and plastic materials often used in the infrastructure were evaluated for compatibility in various ethanol blends, biobutanol, and biodiesel.   Biofuels used in the study include various concentrations of ethanol (10%, 17%, 25%,  50% & 85%), biobutanol and biodiesel, and Ref Fuel C (a gasoline surrogate).  Isobutanol concentrations of 16% and 24% were evaluated in order to match the oxygen content of 10% and 15% ethanol, respectively.   The majority of the specimens were submerged within the liquid fuels, but a smaller group was exposed to the test fuel vapors for comparison.  Analysis included volume swell, hardness changes and dynamic mechanical analysis for all the different test fuels using similar materials.  A theoretical solubility analysis was performed for each polymer type and test fuel using the available Hansen solubility parameters (obtained from literature sources).  Results obtained thus far will be presented and discussed.