| abstract |
The invention provides methods for producing methanol, higher alcohols (containing 2 or more carbons), in particular ethanol, or diesel fuel from biological wastes such as manure, sewage, and crop wastes, as well as from other organic materials. In the methods, organic material is first fermented by anaerobic microorganisms to a biogas consisting primarily of methane and carbon dioxide. The biogas is then converted to synthesis gas consisting primarily of CO and H2. The synthesis gas is then contacted with a liquid fuel production catalyst to synthesize higher alcohols or other liquid fuels. The invention involves converting CO2 in the biogas to synthesis gas by combining a CO2 reforming reaction with steam reforming or partial oxidation to convert the biogas to synthesis gas. The invention also provides methods involving recirculating CO2 from the output of the liquid fuel production reaction to one or more of the fermentation reaction, the CO2 reforming reaction, or the liquid fuel production reaction. |