Dec 13, 2011

Isobutanol-gasoline Blend Superior to E15 Fuel

You’ve probably heard a lot about ethanol, the renewable fuel that was once a darling of some environmentalists. But in the past few years, ethanol has come under fire even as the Obama administration has sought to increase its use by giving provisional approval to so-called E15 -- a blend of 15 percent ethanol and 85 percent gasoline. Car makers and manufacturers of marine engines have questioned the use of E15, suggesting it will result in engine damage. Now there seems to be a logical alternative that provides many of the advantages of ethanol with few of the downsides: It’s called isobutanol.

The National Marine Manufacturers Association (NMMA) just released a report evaluating isobutanol as a petroleum blendstock for the boating industry. Over the summer, NMMA conducted two tests -- one for emissions and another for product -- to evaluate the effects of butanol-blended fuels in a harsh marine environment, which has similarities to use in recreational vehicles and other vehicles that are idle for extended periods. The project aimed to determine if isobutanol could be a better alternative to ethanol blends, and the results were promising.

The emissions tests compared a 16.1 percent isobutanol blend to indolene, the standard gasoline used for engine testing. The results showed a reduction of carbon monoxide from the isobutanol-blended fuel, compared to indolene. They also revealed that hydrocarbons and nitrogen oxide emissions were virtually the same between the two fuels.

“It’s great to have another third party verify the benefits of isobutanol," says Chris Ryan, president of Gevo, a maker of the fuel. “The product attributes of isobutanol, made in retrofitted ethanol plants, can solve the problems associated with current-generation biofuels.”

Isobutanol is compatible with gasoline engines and infrastructure such as pipelines and fuel pumps, which can be damaged by ethanol’s corrosive properties. Isobutanol can be blended into gasoline at higher percentages than ethanol, and, unlike ethanol-blended gasoline, isobutanol blends do not cause phase separation when water enters the fuel system. This is a critical distinction between ethanol and isobutanol blends.

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