Higher Blends of Mixed Alcohol Fuel

Ethanol is an excellent fuel additive and provides many environmental and economic benefits.  This project is attempting to improve on the economic and environmental benefits by mixing ethanol, propanol, butanol, and other alcohols with gasoline.  The goal is to meet the requirements of the Renewable Fuels Standard (RFS) and expand the use of corn-based liquid transportation fuels.

Currently, the market for ethanol is about 13.3 billion gallons of ethanol, displacing about 9.5 percent of the US gasoline.  Increasing the ethanol content above the 10 percent blend wall is not sufficient to meet the requirements of the Renewable Fuels Standard.  In order to meet the Renewable Fuels Standard targets by 2022, we must blend about 26 percent ethanol in all the gasoline sold in the US.

Alcohols other than ethanol have been developed for commercial production.  The near term opportunity is butanol.  Butanol has advantages and disadvantages compared to ethanol.  This project is looking at mixing several different corn derived alcohols including butanol with ethanol and gasoline to see if there is engine performance improvement.  The main objective is to test higher volumes of mixed alcohol fuels to determine if there is a synergy in alcohol mixtures.  

So far, this project has evaluated many different combinations of alcohols including ethanol, propanol, butanol, pentanol, and hexanol. The properties that are measured include many standard tests that are conducted by engineers.  They evaluate combustion properties, anti-knock, evaporation, handling, cold start and mileage.  The results were put into a computer model to predict the fuel properties of the blended fuel.  This allowed scientists to evaluate and select specific blend combinations to test and evaluate the actual fuel properties compared to a normal gasoline.

Source: Andre Ickes and Thomas Wallner, Argonne National Laboratory