Fermentation of glucose with recycle of non-fermented components

• US 4,497,896 A
• Filed: 07/19/1982
• Issued: 02/05/1985
• Est. Priority Date: 07/19/1982
• Status: Expired due to Term

• Current Assignee: St. Lawrence Nanotechnology,Inc.
• Original Assignee: St. Lawrence Nanotechnology,Inc.
• Inventors: Assarsson, Per G., Nagasuye, Joseph H.
• Primary Examiner(s): Jones, Raymond
• Assistant Examiner(s): Minnick, Marianne S.
• Application Number:
  US06/399,228
• Time in Patent Office: 932 Days
• Field of Search: 435/161, 435/162, 435/163, 435/165
• US Class Current: 435/161
• CPC Class Codes: B01D 3/001 Processes specially adapted for distillation or rectification of fermented solutions
• CPC Class Codes: C12P 7/06 Ethanol, i.e. non-beverage
• CPC Class Codes: Y02E 50/10 Biofuels, e.g. bio-diesel

Abstract

A feedstock slurry of starch and acid is continuously moved through a high intensity tubular starch hydrolyzer to produce a fluid hydrolyzate containing glucose. This glucose-containing fluid is then fermented to form a fermentation product containing ethanol which is then distilled to separate the ethanol from the residue of the distillation which contains non-fermented carbohydrate materials. At least part of the distillation residue is recycled as part of the feedstock slurry of starch and acid to the hydrolyzer, thus allowing a substantial portion of the previously unfermented feedstock to be hydrolyzed to a fermentable glucose-containing fluid.

Claims

1. A process for producing ethanol which comprises:

(a) continuously moving a slurry of carbohydrate material through a confined tubular preheat zone and transferring sufficient heat to the slurry whereby it passes through a gelation stage and forms into a hot free flowing liquid and immediately forcing said hot liquid through a restrictive opening and into a confined tubular reaction zone accompanied by a sudden decrease in pressure at a rate so that the carbohydrate material is made highly reactive and continuously moving the highly reactive carbohydrate material, together with an acid hydrolyzing agent, through the tubular reaction zone as a single hydrolysis stage to produce a hydrolyzate in fluid form containing at least 85% glucose,

(b) fermenting the glucose-containing fluid to form a fermentation product containing ethanol,

(c) distilling the fermentation product to separate ethanol from a distillation residue containing non-fermented carbohydrate materials and

(d) passing at least part of the obtained distillation residue containing non-fermented carbohydrate materials through the single hydrolysis state (a) whereby a portion of said non-fermented materials is hydrolyzed to a fermentable glucose-containing liquid.

2. A process according to claim 1 wherein the carbohydrate material is starch or a starch-containing material.

3. A process for producing ethanol which comprises:

(a) continuously moving a feedstock slurry of starch and acid through a high intensity tubular starch hydrolyzer as a single hydrolysis stage to produce a hydrolyzate in fluid form containing glucose,

(b) fermenting the glucose-containing fluid to form a fermentation product containing ethanol,

(c) distilling the fermentation product to separate the ethanol from a distillation residue containing non-fermented carbohydrate materials and,

(d) recycling at least part of the obtained distillation residue as part of the starch and acid slurry feedstock to the single hydrolysis stage whereby a portion of the recycled non-fermented carbohydrate materials is hydrolyzed together with the starch to a fermentable glucose-containing fluid.

4. A process according to claim 3 wherein a hydrolysate containing at least 85% glucose is formed within about 3 minutes in the hydrolyzer.

5. A process for producing ethanol which comprises:

(a) continuously moving a feedstock slurry of ground cereal grain and acid through a high intensity tubular starch hydrolyzer as a single hydrolysis stage to produce a hydrolyzate in fluid form containing glucose together with fibre, protein and other residues from the cereal grain,

(b) fermenting the glucose-containing fluid to form a fermentation product containing ethanol,

(c) distilling the fermentation product to separate the ethanol from a distillation residue containing non-fermented materials and,

(d) recycling at least part of the obtained distillation residue as part of the feedstock to the single hydrolysis stage whereby a portion of the recycled non-fermented carbohydrate materials is hydrolyzed together with the cereal grain to a fermentable glucose-containing fluid.

6. A process according to claim 5 wherein a hydrolysate containing at least 85% glucose is formed within about 3 minutes in the hydrolyzer.

7. A process according to claim 6 wherein the cereal grain is corn.