Process and method for improving the water reuse, energy efficiency, fermentation and products of an ethanol fermentation plant

Abstract

A method of hydrothermally treating stillage by heating stillage to 200 degrees F.-350 degrees F., altering the physicochemical properties of the stillage by making solids in the stillage less hydrophilic, enabling facile separation of the stillage into a high protein solids fraction, a stickwater fraction, and an oil fraction due to the altering step, and, creating unique product fractions including the high protein solids fraction, the stickwater fraction, and the oil fraction. Oil, stickwater, high protein solids fraction, high protein meal, metabolites, biomass, and media obtained from the methods above.

What is claimed is: 
     
         1 . A method of hydrothermally treating stillage, including the steps of:
 heating stillage to 200 degrees F.-350 degrees F.;   altering the physicochemical properties of the stillage by making solids in the stillage less hydrophilic;   enabling facile separation of the stillage into a high protein solids fraction, a stickwater fraction, and an oil fraction due to said altering step; and,   creating unique product fractions including the high protein solids fraction, the stickwater fraction, and the oil fraction.   
     
     
         2 . The method of  claim 1 , wherein said heating step is further defined as heating stillage to 220 degrees F.-300 degrees F. 
     
     
         3 . The method of  claim 1 , wherein the heating step is performed for 3-180 minutes. 
     
     
         4 . The method of  claim 1 , after said enabling step, further including the step of cooling the stillage to less than 212 degrees F. 
     
     
         5 . The method of  claim 1 , wherein the stillage is whole stillage. 
     
     
         6 . The method of  claim 1 , wherein the stillage is diluted stillage. 
     
     
         7 . The method of  claim 6 , where a diluent in the diluted stillage is chosen from the group consisting of water, process water, steam, and process vapor. 
     
     
         8 . The method of  claim 7 , wherein the process vapor is chosen from the group consisting of flash steam, distillation vapor, distillation vapor condensate, evaporated thin stillage vapor, evaporated thin stillage vapor condensate, evaporated stickwater vapor, evaporated stickwater vapor condensate, dryer vapor, and dryer vapor condensate. 
     
     
         9 . The method of  claim 1 , further including the step of concentrating the stillage. 
     
     
         10 . The method of  claim 1 , wherein the stillage is thin stillage. 
     
     
         11 . The method of  claim 1 , wherein the stillage is thick stillage 
     
     
         12 . The method of  claim 11 , where the thick stillage is produced by a method chosen from the group consisting of removal of water from stillage to concentrate solids, filtration of stillage, centrifugation of whole stillage under centrifuge operating conditions promoting transport of more solids into the centrate, addition of solids to thin stillage, particle size reduction of stillage to increase the suspended solids in the feed to hydrothermal treatment, particle size reduction of grain or a grain slurry to increase the suspended solids in the feed to hydrothermal treatment, and combinations thereof 
     
     
         13 . The method of  claim 1 , wherein said enabling step further includes a separating step chosen from the group consisting of gravity, screens, filtration, membranes, hydrocyclones, centrifugation, decanter centrifugation, three-phase decanter, and dissolved air flotation. 
     
     
         14 . The method of  claim 13 , where said separating step is further defined as separating the stillage into a light phase which is substantially oil and a heavy phase which is substantially stickwater and high-protein solids, and separating the heavy phase into a high protein solids phase and a low solids stickwater phase. 
     
     
         15 . The method of  claim 14 , wherein the separating the stillage into a light phase step is performed with a series of centrifugal separators. 
     
     
         16 . The method of  claim 14 , wherein said separating the heavy phase step is performed with a decanting centrifuge. 
     
     
         17 . The method of  claim 13 , wherein said separating step is further defined as separating the stillage into a light phase containing stickwater and oil and a heavy phase containing substantially the high protein solids fraction, and separating the light phase to produce a low solids stickwater fraction and an oil fraction. 
     
     
         18 . The method of  claim 17 , wherein the separating the stillage into a light phase step is performed with a decanter. 
     
     
         19 . The method of  claim 17 , wherein the separating the light phase step is performed with a centrifuge. 
     
     
         20 . The method of  claim 17 , wherein the separating the light phase step is performed by quiescent decantation. 
     
     
         21 . The method of  claim 20 , further including the step of separating any emulsion present in the light phase of quiescent decantation by an additional centrifugation step. 
     
     
         22 . The method of  claim 13 , wherein said separating step is further defined as performing quiescent decantation to produce a bottom heavy phase which is substantially the low solids stickwater fraction and a top light phase which is substantially high protein solids and oil. 
     
     
         23 . The method of  claim 22 , further including the step of separating the top light phase into an oil fraction, a high protein solids fraction, and additional low solids stickwater fraction. 
     
     
         24 . The method of  claim 13 , wherein said separating step is performed with a single separation device chosen from the group consisting of a tricanter, a three-phase nozzle centrifuge, and a three-phase disk stack centrifuge. 
     
     
         25 . The method of  claim 24 , wherein fractions obtained by the tricanter include a high protein solids fraction, a stickwater fraction, and a stickwater/oil emulsion. 
     
     
         26 . The method of  claim 25 , wherein the stickwater/oil emulsion is separated to produce an oil fraction and a second stickwater fraction. 
     
     
         27 . The method of  claim 13 , wherein the stillage is chosen from the group consisting of whole stillage, diluted stillage, concentrated stillage, thin stillage, and thick stillage. 
     
     
         28 . Oil recovered from the method of  claim 13 . 
     
     
         29 . Stickwater recovered from the method of  claim 13 . 
     
     
         30 . High protein solids fraction recovered from the method of  claim 13 . 
     
     
         31 . The method of  claim 13 , further including the step of drying the high protein solids to a high protein meal. 
     
     
         32 . High protein meal recovered from the method of  claim 31 . 
     
     
         33 . The method of  claim 13 , further including a step chosen from the group consisting of recycling as fermentation makeup water at least a portion of the stickwater to a process step upstream of fermentation in an ethanol plant, filtering at least a portion of the stickwater fraction, dehydrating at least a portion of the stickwater fraction, concentrating at least a portion of the stickwater fraction, removing glycerol, removing organic acids, removing organic compounds, removing inorganic compounds, adding agents to at least a portion of the stickwater fraction to precipitate components, treating at least a portion of the stickwater fraction and removing fermentation inhibitors, and combinations thereof. 
     
     
         34 . A method of performing ethanol fermentation including the steps of:
 treating stillage to enable facile separation by heating the stillage to a temperature of 200 degrees F. to 350 degrees F.; and   separating the treated stillage to recover a high protein solids fraction, a stickwater fraction, and an oil fraction.   
     
     
         35 . The method of  claim 34 , further including the step of concentrating the stillage prior to treatment. 
     
     
         36 . The method of  claim 34 , further including a step chosen from the group consisting of recycling as fermentation makeup water at least a portion of the stickwater to a process step upstream of fermentation in an ethanol plant, filtering at least a portion of the stickwater fraction, dehydrating at least a portion of the stickwater fraction, concentrating at least a portion of the stickwater fraction, removing glycerol, removing organic acids, removing organic compounds, removing inorganic compounds, adding agents to at least a portion of the stickwater fraction to precipitate components, treating at least a portion of the stickwater fraction and removing fermentation inhibitors, and combinations thereof. 
     
     
         37 . Oil recovered from the method of  claim 34 . 
     
     
         38 . Stickwater recovered from the method of  claim 34 . 
     
     
         39 . The high protein solids fraction recovered from the method of  claim 34 . 
     
     
         40 . The method of  claim 39 , further including the step of drying the high protein solids to a high protein meal. 
     
     
         41 . High protein meal recovered from the method of  claim 40 . 
     
     
         42 . A method of performing ethanol fermentation, including the steps of:
 separating whole stillage into stillage and wet cake;   hydrothermally fractionating the stillage to create unique product fractions by heating the stillage to a temperature of 200 degrees F. to 350 degrees F.;   separating the heat treated stillage into a high protein solids fraction, a first stickwater fraction and a stickwater/oil emulsion;   recovering oil from the stickwater/oil emulsion;   recovering a second stickwater fraction from the stickwater/oil emulsion and adding the second stickwater fraction to the first stickwater fraction; and   further processing the first and second stickwater fractions by a process selected from the group consisting of recycling at least a portion of the stickwater to a front end of an ethanol plant, biological processing and chemical processing, and using the first and second stickwater fractions as growth media in said processing step.   
     
     
         43 . A method of performing ethanol fermentation, including the steps of:
 separating whole stillage into wet cake and stillage;   hydrothermally treating stillage by heating the stillage to a temperature of 200 degrees F. to 350 degrees F.; and   adding all or a portion of the treated stillage to the ethanol fermentation step or an operation upstream of fermentation.   
     
     
         44 . A method of performing ethanol fermentation, including the steps of:
 separating whole stillage into a first cut solids stream and thin stillage;
 performing a particle size reduction step on all or a portion of the first cut solids; 
 returning the reduced particle size solids to the thin stillage stream to produce thick stillage; 
 hydrothermally treating the thick stillage by heating to a temperature of 200 degrees F. to 350 degrees F.; and 
 adding all or a portion of the treated stillage to the ethanol fermentation step or an operation upstream of fermentation. 
   
     
     
         45 . A method of increasing bioavailability of stillage components to microorganisms, including the steps of:
 hydrothermally treating stillage by heating the stillage to a temperature of 200 degrees F. to 350 degrees F.;   increasing the bioavailability of components in the stillage; and   adding the hydrothermally treated stillage to media and providing to microorganisms.   
     
     
         46 . The method of  claim 45 , wherein said increasing the bioavailability of components is further defined as a step chosen from the group consisting of hydrolyzing oligosaccharides into monosaccharides and disaccharides, unfolding protein matrices, denaturing protein, hydrolyzing protein, and combinations thereof. 
     
     
         47 . A product chosen from the group consisting of glycerol, organic acids, organic compounds, inorganic compounds, and fermentation inhibitors recovered by the method of  claim 33 . 
     
     
         48 . A product chosen from the group consisting of glycerol, organic acids, organic compounds, inorganic compounds, and fermentation inhibitors recovered by the method of  claim 36 .