Sterilization of fermentation vessels by ethanol/water mixtures
First Claim
1. A method of sterilizing a fermentation vessel used in a batch fermentation process that includes an associated alcohol distillation or purification facility for purifying alcohol produced in the fermentation vessel to a higher alcohol concentration, wherein said fermentation vessel is intermittently emptied of fermented product, including alcohol, and cleaned, comprising the steps of:
- withdrawing a sterilizing alcohol in aqueous solution from the distillation or purification facility with a sufficient concentration of alcohol to kill undesirable microorganisms;
sterilizing said emptied and cleaned fermentation vessel by introducing only said sterilizing alcohol in aqueous solution into the fermentation vessel;
withdrawing said sterilizing alcohol in aqueous solution from the fermentation vessel following the sterilization of said fermentation vessel and returning the sterilizing alcohol in aqueous solution to said distillation or purification facility.
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Accused Products
Abstract
A method for sterilizing process fermentation vessels with a concentrated alcohol and water mixture integrated in a fuel alcohol or other alcohol production facility. Hot, concentrated alcohol is drawn from a distillation or other purification stage and sprayed into the empty fermentation vessels. This sterilizing alcohol/water mixture should be of a sufficient concentration, preferably higher than 12% alcohol by volume, to be toxic to undesirable microorganisms. Following sterilization, this sterilizing alcohol/water mixture can be recovered back into the same distillation or other purification stage from which it was withdrawn. The process of this invention has its best application in, but is not limited to, batch fermentation processes, wherein the fermentation vessels must be emptied, cleaned, and sterilized following completion of each batch fermentation process.
20 Citations
21 Claims
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1. A method of sterilizing a fermentation vessel used in a batch fermentation process that includes an associated alcohol distillation or purification facility for purifying alcohol produced in the fermentation vessel to a higher alcohol concentration, wherein said fermentation vessel is intermittently emptied of fermented product, including alcohol, and cleaned, comprising the steps of:
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withdrawing a sterilizing alcohol in aqueous solution from the distillation or purification facility with a sufficient concentration of alcohol to kill undesirable microorganisms; sterilizing said emptied and cleaned fermentation vessel by introducing only said sterilizing alcohol in aqueous solution into the fermentation vessel; withdrawing said sterilizing alcohol in aqueous solution from the fermentation vessel following the sterilization of said fermentation vessel and returning the sterilizing alcohol in aqueous solution to said distillation or purification facility. - View Dependent Claims (2, 3, 4, 5, 6)
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7. In a batch alcohol producing process wherein successive batches of feedstock are placed sequentially into a fermentation vessel and fermented in the fermentation vessel by alcohol producing microorganisms to produce successive batches of a fermented mixture having a low alcohol concentration not exceeding about 12% alcohol by volume and wherein each successive batch of said fermented mixture is fed into a distillation process in which liquid containing alcohol in said mixture is distilled to a higher concentration alcohol/water solution exceeding 12% alcohol by volume and wherein the interior of the fermentation vessel is sterilized to kill undesirable microorganisms between successive batches, the improvement comprising the steps of:
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withdrawing a portion of the alcohol containing liquid that has been distilled to an alcohol concentration above 12% alcohol content from the distillation process; recirculating said withdrawn portion of alcohol containing liquid back into said fermentation vessel to sterilize the fermentation vessel and kill undesirable microorganisms in the fermentation vessel with only said withdrawn portion of alcohol containing liquid; and returning said withdrawn portion of alcohol containing liquid back into said distillation process. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14)
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15. A process for producing alcohol, comprising the steps of:
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placing a batch of fermentable feedstock or substrate in a fermentation vessel with water and alcohol producing fungi; allowing the fungi to ferment the feedstock or substrate to produce a mixture having a liquid fraction comprising alcohol and water and a solid fraction comprising residual solid by-products of the fermentation process, with the alcohol and water in the liquid fraction having a concentration not exceeding an approximate maximum of twelve percent (12%) alcohol by volume; removing the liquid and solid fractions from the fermentation vessel;
separating the solid fraction from the liquid fraction;distilling the liquid fraction to produce a higher purity alcohol product having an alcohol/water concentration of higher than twelve percent (12%) alcohol by volume; withdrawing a portion of the higher purity alcohol from the alcohol product and spraying the withdrawn portion of the higher purity alcohol product into the fermentation vessel to sterilize the vessel with only said withdrawn portion of higher purity alcohol product; collecting the withdrawn portion of the higher purity alcohol from the fermentation tank; and recombining the withdrawn portion with the higher purity alcohol product that was not withdrawn. - View Dependent Claims (16, 17)
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18. A process for producing alcohol, comprising the steps of:
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placing a batch of fermentable feedstock or substrate in a fermentation vessel with water and alcohol producing fungi; allowing the fungi to ferment the feedstock or substrate to produce a mixture having a liquid fraction comprising alcohol and water and a solid fraction comprising residual solid by-products of the fermentation process; removing the liquid and solid fractions from the fermentation vessel; separating the solid fraction from the liquid fraction; purifying the alcohol in the liquid fraction to a higher purity alcohol/water mixture having a higher alcohol concentration than was produced by the fermentation step; withdrawing a portion of the higher purity alcohol/water mixture; and spraying only said withdrawn portion of the higher purity alcohol/water mixture into the fermentation vessel in vapor form to sterilize the fermentation vessel. - View Dependent Claims (19, 20, 21)
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Specification