Production of alcohol blend usable in flexible fuel vehicles via fischer-tropsch synthesis field of the invention

Abstract

Alternative fuel compositions, blends of the alternative fuel compositions and gasoline, and methods for their preparation and use are disclosed. The alternative fuel compositions ideally include ethanol, isopropyl alcohol, and one or more of sec-butanol and t-butanol, and ideally include no more than 3% methanol, and no more than 15% C₅ or higher alcohols. The fuel compositions can be prepared using Fischer-Tropsch synthesis to convert syngas to a product stream comprising C_2-4 olefins, and hydrolyzing these olefins. The process facilitates isolation of C_2-4 alkanes, because the boiling point difference of these alkanes is significantly lower than that of the C_2-4 alcohols. Ideally, the compositions provide more energy per unit volume than E85, even without the addition of gasoline, although the compositions can be blended with gasoline in any desired ratio. The resulting alternative fuel can be derived, at least in part, from renewable resources, in that the syngas can be derived from renewable resources, and a significant portion of the molecule is derived from the water used to hydrolyze the olefins. The alternative fuel compositions, and blends thereof with gasoline, can help reduce U.S. dependence on foreign crude oil.

Description

[0001]This application is a continuation-in-part of PCT application No. PCT / US07 / 069,635, filed May 24, 2007, which claims priority to U.S. Provisional Application No. 60 / 896,099, filed Mar. 21, 2007.[0002]The present invention relates to alternative fuel compositions which comprise ethanol, isopropyl alcohol, and secondary-butanol and / or t-butanol, as well as blends of these compositions with gasoline.BACKGROUND OF THE INVENTION[0003]Gasoline is derived from crude oil, which is a non-renewable resource of finite supply. Extensive research effort is now being directed toward replacing some or all petroleum-based transportation fuels with gasoline / ethanol blends such as E85 (85% ethanol and 15% gasoline by volume). E85 suffers from a significant loss (roughly 20%) in energy per unit volume relative to gasoline. However, flexible fuel vehicles can run efficiently on these fuels, and the high oxygenate content makes them very clean burning fuels.[0004]Because ethanol suffers from relat...

AI Technical Summary

Benefits of technology

[0146]Using the microchannel reactors described herein, one can efficiently control the heat generated from the exothermic Fischer-Tropsch reaction, and, with appropriate use of heat exchangers, ideally transfer this heat energy to, and use the energy in, the olefin hydration step. Ideally, using the microfluidic approach, whereas water and olefins will separate in a large scale Fischer-Tropsch reactor, and may need t

Problems solved by technology

E85 suffers from a significant loss (roughly 20%) in energy per unit volume relative to gasoline.

However, the use of n-butanol as a viable energy source is not without its problems.

That is, sugar can be fermented, but it is difficult and expensive to con