Synthetic Gasoline from Biomass

Clean and renewable liquid fuels from biomass offer reduced new emission of CO2 and less dependence on expensive and unreliable foreign oil. Currently, bioethanol serves in the U.S.A. as bled for gasoline but eventually it could replace gasoline in passenger cars altogether. Ethanol, however, contains only 2/3 of the energy of gasoline on equal volume basis, and if used at high concentration, it requires retrofitting of existing cars. It could therefore be economically and technologically more attractive to convert biomass to a hydrocarbon-based synthetic gasoline (SG), i.e., a hydrocarbon mixture performing similarly to petroleum-derived gasoline. The proposed project will develop a new, novel biomass derived gasoline fuel. Specifically, we will convert methanol catalytically to C5-C10 isoalkanes. Methanol could be obtained from biomass, either directly by biochemical processes, or indirectly form synthesis gas (CO + H2) produced by biomass gasification. In the proposed catalytic conversion of methanol to SD, the hydrocarbon product is free of any naphthenes and aromatics, and of heteroatom and metal impurities. Co-produced isobutene could be reacted separately to provide isooctane and/or isononsne, or ETBE as additional fuel liquid with very high octane. The overall SG product may be superior to conventional gasoline in having higher ignition and combustion efficiencies, less toxicity and less emission of pollutants such and CO and THC. At methanol cost of ~35 ¢ per gallon, this SG could be produced at about half the price of current gasoline. Phase I aims at (1) showing feasibility and substantiating preliminary results, and (2) preparing simulated SG samples of relevant isoalkane compositions and analyzing them for their gasoline specs, to compare them with conventional gasoline. In Phase II of this project, we shall construct and operate a bench scale methanol conversion apparatus to afford a full technical feasibility study with an eye toward commencing a pilot plant engineering design effort, possibly through partnership with a biomass processing business and/or an oil refining company. Post Phase II, a demonstration scale facility will be constructed to produce fuels for large scale engine testing.