15-02: Direct Catalytic Conversion of Aqueous Ethanol Streams into Hydrocarbon Blendstock

We report ethanol transformation into a blendstock hydrocarbon fuel through a one-step catalytic process. At present, we have demonstrated that ethanol (5-100% in water or fermentation media) can be converted to gasoline-equivalent blendstock over a metal exchanged zeolite without added hydrogen at near atmospheric pressure. This would allow the direct extension of fermentation alcohols into the drop-in fuel markets. Our work shows that water concentration in dilute ethanol or simulated fermentation stream has no effect on the catalyst or product distribution. The blendstock consists of a mixture of C₃–C₁₆ hydrocarbons containing paraffin, iso-paraffins, olefins, and aromatic compounds with a calculated motor octane number of 95. The blendstock produced by our process has been engine tested and found to be compatible.  Preliminary cost analysis suggests that the conversion cost is acceptable.  The catalyst was observed to become coked after several hours. The coking time was dependent on space velocity and the catalyst could be regenerated at 450°C in air.  Fractional collection of the fuel product allows for the different fractions to be used as blendstock for gasoline, diesel, or jet fuel.  The advantages of this approach include bypassing the ethanol “blend-wall” and the use of current and near-term bioethanol fermentation infrastructure.