Abstract: An ethanol unit and anaerobic digestion/bio-fertilizer unit are integrated with a cattle feedlot (or dairy operation), wherein a continuous, balanced process yields a sanitary, low- to zero-pollution, and economically efficient production of “clean beef” (or milk), fuel ethanol, and bio-gas/bio-fertilizer. Fossil fuel consumption is substantially reduced, even eliminated, and 100% of the cattle waste is treated in digesters wherein it is converted into medium-BTU gas (bio-gas), organic fertilizer and bio-compost. The ethanol unit serves the purposes of ethanol production, grain pretreatment to produce feed for the cattle and production of a thin stillage which is fed to the digesters. The grain is first processed in the ethanol unit, where the starch portion is converted into ethanol and CO2.

Abstract: An integrated continuous process for the production of ethanol and a bio-gas containing methane is disclosed. The process comprises the following steps. First, grain is fermented in an aqueous medium to produce ethanol in the medium which contains a wet distillers' grain with solubles as a wet grain residue and carbon dioxide. Next, the wet grain is feed to livestock in a feedlot which has slatted floors. The wet grain residue constitutes 25-80% of a feed ration of the livestock on a dry weight basis. The feed ration consists essentially of the 25-80% wet grain residue and grain. Third, the manure from the livestock is collected from beneath the slatted floor. Fourth, the collected manure is digested anaerobically with microorganisms to produce the bio-gas containing methane and, as a residue, a bio-fertilizer. Fifth, the bio-gas is combusted to produce heat. Sixth, the grain is dry milled utilizing heat produced by the combustion.

Abstract: A methanol synthesis and an ethanol synthesis are integrated into a single continuous process with the by-product carbon dioxide generated in the ethanol synthesis being utilized in the methanol synthesis. The methanol synthesis and ethanol synthesis can be further integrated with isobutylene synthesis with by-product hydrogen formed during isobutylene synthesis being used as a raw material in the methanol synthesis. In the preferred embodiments the ethanol synthesis utilizes Zymomonas mobilis bacteria in anaerobic fermentation in order to maximize the amount of carbon dioxide produced in a form which can be utilized in the methanol synthesis, to reduce carbon dioxide emissions and to provide an ethnaol product which is highly suitable for reaction with the isobutylene to form ethyl tertiary butyl ether.