# US 4,395,488 A · Drive-through pit production of ethanol > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 4,395,488 A - Document ID: US4395488A - Status: Granted - Kind: A - Application number: 06/301,718 - Filed: 1981-09-14 - Granted: 1983-07-26 - Earliest claimed: 1981-09-14 - Inventors: Delton J. Rowe - Web page: https://patentgrep.com/patent/US4395488A ## CPC - C12P 7/06: Ethanol, i.e. non-beverage - Y02E 50/10: Biofuels, e.g. bio-diesel - Y10S 435/801: Anerobic cultivation - Y10S 435/819: Fermentation vessels in series - C12P: FERMENTATION OR ENZYME-USING PROCESSES TO SYNTHESISE A DESIRED CHEMICAL COMPOUND OR COMPOSITION OR TO SEPARATE OPTICAL ISOMERS FROM A RACEMIC MIXTURE {(brewing of beer C12C; producing vinegar C12J; producing specific peptides or proteins C07K; producing enzymes C12N9/00; DNA or RNA concerning genetic engineering, vectors, e.g. plasmids, or their isolation, preparation or purification C12N15/00; measuring or testing processes involving enzymes or microorganisms C12Q; measuring or testing processes involving nucleic acid amplification reactions C12Q1/6844; fermentation processes to form a food composition, A21 or A23; compounds in general, see the relevant compound class, e.g. C01, C07)} - Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION - Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS ## Abstract Ethanol (C.sub.2 H.sub.5 OH) is produced efficiently by employing a drive-through pit in which carbohydrate-containing material is fermented by hydrolyzing agents such as enzymes. The configuration and depth of the pit are such as to permit conventional farm vehicles to have ready access to the pit, thereby enabling the pit to be loaded and unloaded conveniently. The pit is insulated on its sides and bottom and is closed at the top by a heat-insulating cover. The pit is heated to assist the fermentation process. After several days of heating, the pit is drained through a sediment trap and the filtered pit drainage is separated into concentrated ethanol and a mixture of water and enzymes. The solid residue left in the pit is removed for use as feed or fertilizer. The separated water and hydrolyzing agents are stored in a reservoir for subsequent flooding of the pit when a new quantity of carbohydrate-containing material is added to the pit. ## Claims ### Claim 1 A method for producing ethanol, comprising the steps of: depositing carbohydrate-containing material into a pit having a bottom with one end lower than the other and heating pipes within grooves in the bottom below the surface of the bottom; driving a vehicle into the pit and using it to spread said carbohydrate-containing material; flooding the pit with a mixture of water and hydrolyzing agents until the material is covered with at least six inches of liquid; fermenting the contents of the pit; draining the liquid contents of the pit from the lower end of the pit; separating the drained liquid into concentrated ethanol and a mixture of water and hydrolyzing agents; removing the mixture of water and hydrolyzing agents for later use in flooding the pit; and driving a vehicle into the pit and removing the solid residue from the pit with the vehicle. ### Claim 2 (depends on 1) The method of claim 1, including the additional steps of covering the pit during the fermentation process with a heat-insulating cover and pumping hot water through said pipes. ### Claim 3 (depends on 1) The method of claim 1, including the additional step of storing the drained liquid contents of the pit in a reservoir prior to the step of separating the drained liquid into concentrated ethanol and a mixture of water and hydolyzing agents. ### Claim 4 (depends on 1) The method of claim 1, wherein the step of separating the drained liquid into concentrated ethanol and a mixture of water and hydrolyzing agents is carried out by distillation, whereby a distillate of concentrated ehtanol and a distilland of water and hydrolyzing agents are formed. ### Claim 5 Apparatus for producing ethanol by the fermentation of carbohydrate-containing material, comprising: a pit into which carbohydrates-containing material can be placed and flooded with a solution for producing ethanol; a sediment trap adjacent the pit for draining the pit and removing solids from the drained liquid; separation equipment for producing concentrated ethanol and a mixture of water and hydrolyzing agents; a storage reservior for storing a mixture of water and hydrolyzing agents for subsequent use in producing ethanol; a cover for the pit to seal the pit during the fermentation process; said pit including a bottom wall, side walls and sloping end walls; said bottom wall being impervious to liquids, the bottom wall being inclined with respect to the horizontal so that one end of the pit is deeper than the other; said side walls extending upwardly from the bottom wall, the side walls being impervious to liquids; said sloping end walls extending outwardly from the bottom wall at an angle to the horizontal, the end walls being impervious to liquids; generally horizontal aprons extending laterally outwardly from the end walls; a plurality of grooves formed in the bottom wall; heating pipes located in the grooves, the heating pipes adapted to convey heated fluid so that the contents of the pit can be heated; said grooves having a depth greater than the diameter of said pipes, whereby a vehicle may be driven over said bottom wall without rupturing said pipes; and a drainage gate formed in one of the side walls adjacent the deeper end of the pit. ### Claim 6 (depends on 5) The apparatus of claim 5, additionally including a reservoir for storing drained liquid contents of the pit prior to separation into concentrated ethanol and a mixture of water and hydrolyzing agents. ### Claim 7 (depends on 6) The apparatus of claim 6, wherein the reservoirs are heated with a solar selective coating and are surrounded by a light-transmissive cover spaced a small distance from the surface of the reservoirs. ### Claim 8 (depends on 5) The apparatus of claim 5, wherein the separation equipment is in the form of a boiler, a distillation column, and a condenser.