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Phase Partitioning from Theanol Blend Gasolines
Citation:
SPIDLE, D. L., E. Carey, AND JIM WEAVER. Phase Partitioning from Theanol Blend Gasolines. Presented at 23rd National Tanks Conference and Expo, St Louis, MO, March 19 - 21, 2012.
Impact/Purpose:
see description
Description:
In recent years, the use of ethanol and other alcohols as motor fuel additives has increased. Additionally, ethanol production has expanded due to the potential use of ethanol as a primary fuel source. Historical patterns of gasoline composition show strong dependency on regulatory requirements. Currently, ethanol is used in approximately 90% of U.S. gasoline. As the use of ethanol fuel blends increases, future spills containing ethanol are likely to become more frequent. While benzene, toluene, ethyl benzene and xylenes (BTEX) have low solubilities in water, the presence of ethanol could increase the aqueous solubility of the BTEX compounds. This cosolvency effect was evaluated by mixing fuel blends containing a range of ethanol concentrations (10%-90%) with water and measuring the concentrations of ethanol and BTEX compounds at various time points from 1 to 100 hours. Experimental results revealed two trends associated with the portioning effects of ethanol on the concentrations of BTEX compounds in water. While water exposed to fuel blends of 20% and less ethanol had very similar aqueous concentrations of BTEX compounds, water in contact with fuel blends of 50% and 90% ethanol contained dramatically higher BTEX concentrations. At higher ethanol content, the BTEX concentrations dropped by a factor of two or more during the 100 hour equilibration period. Depending on the release circumstances, these increased BTEX concentrations may be signification when spills or leaks occur that contain 50% or more ethanol.
