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Geothermal source potential and utilization for methane generation and alcohol production

Technical Report ·
DOI:https://doi.org/10.2172/6085874· OSTI ID:6085874

A study was conducted to assess the technical and economic feasibility of integrating a geothermally heated anaerobic digester with a fuel alcohol plant and cattle feedlot. Thin stillage produced from the alcohol production process and manure collected from the cattle feedlot would be digested in anaerobic digesters to produce biogas, a mixture of methane and carbon dioxide, and residue. The energy requirements to maintain proper digester temperatures would be provided by geothermal water. The biogas produced in the digesters would be burned in a boiler to produce low-pressure steam which would be used in the alcohol production process. The alcohol plant would be sized so that the distiller's grains byproduct resulting from the alcohol production would be adequate to supply the daily cattle feed requirements. A portion of the digester residue would substitute for alfalfa hay in the cattle feedlot ration. The major design criterion for the integrated facilty was the production of adequate distiller's grain to supply the daily requirements of 1700 head of cattle. It was determined that, for a ration of 7 pounds of distiller's grain per head per day, a 1 million gpy alcohol facility would be required. An order-of-magnitude cost estimate was prepared for the proposed project, operating costs were calculated for a facility based on a corn feedstock, the economic feasibility of the proposed project was examined by calculating its simple payback, and an analysis was performed to examine the sensitivity of the project's economic viability to variations in feedstock costs and alcohol and distiller's grain prices.

Research Organization:
Idaho National Engineering Lab., Idaho Falls (USA); CH2M Hill, Boise, ID (USA)
DOE Contract Number:
AC07-76ID01570
OSTI ID:
6085874
Report Number(s):
EGG-2137; ON: DE82003800
Country of Publication:
United States
Language:
English