PNNL researchers develop technology to boost use of ethanol as octane booster

May 27, 2020 |

In Washington state, technology developed by researchers at the U.S. Department of Energy’s Pacific Northwest National Laboratory could pave the way for increased fuel economy and lower greenhouse gas emissions as part of an octane-on-demand fuel-delivery system.

Designed to work with a car’s existing fuel, the onboard separation technology is the first to use chemistry—not a physical membrane—to separate ethanol-blended gasoline into high- and low-octane fuel components. An octane-on-demand system can then meter out the appropriate fuel mixture to the engine depending on the power required: lower octane for idling, higher octane for accelerating.

Studies have shown that octane-on-demand approaches can improve fuel economy by up to 30 percent and could help reduce greenhouse gas emissions by 20 percent. But so far, the pervaporation membranes tested for octane on demand leave nearly 20 percent of the valuable high-octane fuel components in the gasoline.

In proof-of-concept testing with three different chemistries, PNNL’s patent-pending onboard separation technology separated 95 percent of the ethanol out of commercial gasoline. The materials are also effective for separating butanol, a promising high-octane renewable fuel component.

Higher-octane fuels can eliminate knock but are expensive to produce. Ethanol is an inexpensive fuel additive that increases the octane rating to combat knock. The additive modestly curbs greenhouse gas emissions—but reduces vehicle performance and fuel economy. When a car burns gas while sitting at a stop light or idling at the curb, it’s wasting the valuable high-octane fuel better used for acceleration.

That’s where PNNL’s onboard separation technology comes in. As part of an octane-on-demand system, the technology optimizes the available fuel by staging the right fuel for the right time.

Category: Research

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