METHOD OF AND SYSTEM FOR PRODUCING A SYRUP WITH THE HIGHEST CONCENTRATION USING A DRY MILL PROCESS

Abstract

Method of and system for producing the highest concentration of a syrup (e.g., 80% dry matter) using a dry milling process are provided, which include (a) using backend grinding steps and devices for grinding thin stillage, (b) using a clean thin stillage system with two-disc centrifuges and two protein decanters, (c) adding an enriched syrup back to the syrup or evaporator, and (d) splitting two dryers into two independent parallel dryers using one dryer as a protein dryer and the other as a DDG dryer for producing DDGS.

Claims

1. A method of generating concentrated syrup in a dry milling system comprising: a. fermenting and distilling an agricultural substance; b. forming a whole stillage; c. performing a first separating process on the whole stillage; d. forming an overflow liquid based portion and underflow coarse solid portion at the first separating process; e. grinding the underflow coarse solid portion after the first separating process; f. using one or more high speed centrifuges for performing a centrifugation process on the overflow liquid based portion; g. evaporating the overflow liquid based portion at an evaporator from the one or more high speed centrifuge; and h. forming a concentrated syrup.

2. The method of claim 1, generating a solution at the having less than 2% of insoluble solid by using a high G force nozzle centrifuge at the centrifugation process.

3. The method of claim 2, wherein the high G force nozzle centrifuge with the evaporator are able to concentrate the overflow liquid based portion to a syrup having 50%-60% of dry matter.

4. The method of claim 1, wherein the one or more high speed centrifuges comprises a nozzle disc stack centrifuge, which generates a solution having 0.6%-1.2% of insoluble solid.

5. The method of claim 4, wherein the nozzle disc stack centrifuge with the evaporator are able to concentrate the overflow liquid based portion to a syrup having 60%-70% of dry matter.

6. The method of claim 1, wherein the one or more high speed centrifuges comprises double high-speed centrifuges.

7. The method of claim 6, wherein the double high-speed centrifuges comprise a high-speed disc centrifuge and a high-speed disc stack centrifuge.

8. The method of claim 7, wherein the high-speed disc stack centrifuge generates a solution having 0.25%-4% of insoluble solid by volume.

9. The method of claim 6, wherein the double high-speed centrifuges with the evaporator are able to concentrate the overflow liquid based portion to a syrup having greater than 70% of dry matter.

10. The method of claim 6, wherein the double high-speed centrifuges with the evaporator are able to concentrate the overflow liquid based portion to a syrup having 70%-80% of dry matter.

11. The method of claim 1, wherein the one or more high speed centrifuges comprises a disc decanter.

12. The method of claim 11, wherein the a disc decanter with the evaporator are able to concentrate the overflow liquid based portion to a syrup having 70%-80% of dry matter.

13. The method of claim 11, further comprising reducing a viscosity of the syrup by converting glycerol and residual sugars in the syrup to one or more organic acids.

14. A method of generating concentrated syrup in a dry milling system comprising: a. fermenting and distilling an agricultural substance; b. forming a whole stillage; c. performing a first separating process on the whole stillage; d. forming an overflow liquid based portion and underflow coarse solid portion at the first separating process; e. grinding the underflow coarse solid portion after the first separating process; f. using one or more high speed centrifuges for performing a centrifugation process on the overflow liquid based portion; g. evaporating the overflow liquid based portion at an evaporator from the one or more high speed centrifuge h. forming a concentrated syrup; and adding the concentrated syrup back to the evaporator to form a syrup having 80% to 90% of a dry matter.

15. The method of claim 1, wherein the one or more high speed centrifuges comprises two disc centrifuges.

16. The method of claim 14, wherein the dry milling system does not use a drying temperature that destroys heat sensitive nutrients in the syrup.

17. The method of claim 14, further comprising using two parallel dryer lines.

18. The method of claim 17, wherein the two parallel dryer lines produce two different protein contents.

19. A method of increasing a percentage of dry matter in a syrup in a dry milling alcohol producing plant comprising: a. reducing a viscosity of a syrup by reducing a percentage of the insoluble solid in a thin tillage; and b. evaporating water forming a syrup with a dry matter greater than 50% in an evaporator without causing a significant flow and wetting issue that form an amount of scale at an evaporator tube of the evaporator.

20. The method of claim 20, wherein the insoluble solid is less than 2% in the thin stillage.

21. The method of claim 20, further comprising using one or more centrifuges to reduce the percentage of the insoluble solid.

22. The method of claim 22, wherein the one or more centrifuges comprises a high G force nozzle centrifuge.

23. The method of claim 22, wherein the one or more centrifuges comprises a nozzle disc stack centrifuge.

24. The method of claim 22, wherein the one or more centrifuges comprises double high-speed centrifuges.

25. The method of claim 22, wherein the one or more centrifuges comprises a disc decanter.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0045] FIG. 1 is a flow diagram of a typical dry milling process and system for producing ethanol and recovering oil in a backend process.

[0046] FIG. 2 is a flow diagram of a typical dry milling process and system with a front-end grinding to increase the alcohol and oil yield.

[0047] FIG. 3 is a flow diagram of a typical dry milling process and system for producing ethanol and recovering oil and protein at the backend.

[0048] FIG. 4 is a flow diagram of a system for and method of a dry milling process with a backend grinding process and system for increasing the alcohol and oil yields in accordance with some embodiments.

[0049] FIG. 4A is a flow diagram of a system for and method of a dry milling process with a backend grinding and one-disc centrifuge to polish the thin stillage in accordance with some embodiments.

[0050] FIG. 4B is a flow diagram of a system for and method of a dry milling process with a backend grinding and two-disc centrifuges in series to polish thin stillage in accordance with some embodiments.

[0051] FIG. 4C is a flow diagram of a system for and method of a dry milling process having a backend grinding with a disc decanter in accordance with some embodiments.

[0052] FIG. 5 is a flow diagram of a system for and method of a dry milling process with a backend grinding, two-disc centrifuges in series, and a secondary fermentation process and device to produce a high % DS syrup in accordance with some embodiments.

[0053] FIG. 6 is a flow diagram of a variation of the system and method described in FIG. 5 in accordance with some embodiments.

[0054] FIG. 6A is a flow diagram of a variation of the system and method described in FIG. 5 in accordance with some embodiments.

[0055] FIG. 6B is a flow diagram of a variation of the system and method described in FIG. 5 in accordance with some embodiments.

[0056] FIG. 7 is a flow diagram of a system for and method of a dry milling process with a) a backend grinding to increase alcohol, oil, and protein yield, b) two-disc centrifuges in series to produce cleanest thin stillage, c) a secondary fermentation to produce enriched syrup with the highest % DS syrup, d) splitting two dryers in series to two dryers in parallel to produce high protein meal and enriching low protein feed in accordance with some embodiments.

[0057] FIG. 7A is a flow diagram of a variation of the system and method described in FIG. 7 in accordance with some embodiments.

[0058] FIGS. 8A-8E illustrate experimental results in accordance with some embodiments.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0059] FIG. 1 illustrates a typical dry milling process, where corn is processed through a hammer mill (step 11) to break the whole kernels into smaller particles (less than 2.78 mm). Cook water and enzyme is added to the ground corn to liquefy (step 12) the starch. Fermentation is conducted with the addition of yeast to the liquefied corn slurry to convert starch to alcohol in fermentation (step 13). After approximately 30-70 hours fermentation time, the finished beer (generally containing 12% or higher alcohol) is sent to the distillation tower (step 14) to recovery the alcohol produced. The whole stillage from the bottom of the distillation tower (step 14) is send to the decanter (step 15) to remove coarse particles including fiber and large particles of protein, germ and grit for the recovery as a DDG cake. The overflow (thin stillage) from fiber separation (step 15) contains mainly fine particles of protein, germ, oil, oil emulsion and water soluble materials and is sent to the evaporator (step 16) to be concentrated to become syrup containing 25%-40% of DS.

[0060] An oil recovery (step 17) process has been added to the majority of dry milling plant to recover valuable oil during the evaporation process. The syrup can be concentrated to have 25%-40% of DS depending on the capacity and capability of the decanter and evaporator and the % insoluble solid present (measured by volume in a lab centrifuge at 3000G seconds spin) in the thin stillage. The majority of dry mill ethanol plants has 6 to 12% insoluble solids by volume in the thin stillage and produces a 30 to 40% DS syrup.

[0061] FIG. 2 shows a typical dry milling process and system with front-end grinding to increase the alcohol and oil yield. As shown in the process 200 of FIG. 2, solids dewatering (step 221) and particle reduction device (step 222) is added to the process 100 of FIG. 1 to form the process 200 (FIG. 2).

[0062] The whole kernel grains (often maize, corn) go through a hammer mill (step 211) to break up the kernels into smaller particles (less than 2.78 mm). Cook water and enzyme are added to the ground corn in order to liquefy (step 212) the starch. Before sending the liquefaction to the fermenter, the liquefied slurry is sent to the solid dewatering device (step 221) to remove majority of liquid and then send the relatively dry solids to a particle reduce device (step 222) to break up large grit and germ particles to increase the alcohol and oil yield. The combined liquid from solid dewatering process (step 221) and the ground solids from the particle size reduction device (step 222) is then added to the fermenter (step 213) along with yeast to convert starch to alcohol in the fermentor for a fermentation process (step 213). After approximately 30-70 hours of fermentation time, the finished beer (generally containing 12% or higher alcohol) is sent to the distillation tower (step 214) to recover the alcohol.

[0063] The whole stillage from the bottom of the distillation tower (step 214) is sent to the decanter (step 215; a fiber separating process) to remove coarse particles including fiber and large particles of protein, germ and grit for the recovery as DDG cake. The size of solid in the whole stillage after the front-end grinding step in the process 200 will decrease, but those reduced particle size solids will still be recovered in its majority in the decanter's recovery range (step 215; generally down to 5 to 10 micron in their diameter). This results in a percentage of the insoluble solid ranging from 6% to 12% in the thin stillage of the process 200, which has an insoluble solid percentage almost identical to the process 100. Thus, the overflow (thin stillage) from the fiber separation (step 215) contains mainly fine particles of protein, germ, oil, oil emulsion and water soluble materials and is sent to the evaporator (step 216) to be concentrated to have a syrup of about 25 to 40% DS. An oil recovery process (step 217) has been added to the majority of the dry mill plant to recover valuable oil during the evaporation process. The syrup can be concentrated to 25 to 40% of DS depending on the capacity and capability of the decanter and evaporator and the percentage of the insoluble solid present (measured by volume in a lab centrifuge at 3000G seconds spin) in the thin stillage. The majority of the dry mill ethanol plants has 6 to 12% insoluble solids by volume in thin stillage and produces a syrup with 30 to 40% DS (dry solid).

[0064] FIG. 3 is a flow diagram of a typical dry milling process and system for producing ethanol and recovering oil and protein at the backend. As shown in process 300 of FIG. 3, the fiber separation (step 333), fiber washing (step 334), fiber dewatering (step 332) and a thin stillage clarification processes (step 331; disc centrifuge) are additional to the typical dry mill process 100 of FIG. 1 to separate/recover protein and produce high protein meal. In the process 300 of FIG. 3, the whole kernel grains (often maize, corn) go through a hammer mill to break up the kernels into smaller particles (less than 2.78 mm). Cook water and enzyme are added to the ground corn to liquefy the starch. The liquefaction is then added to the fermenter along with yeast to convert starch to alcohol in a fermentor (step 13; fermenting). After approximately 30-70 hours of fermentation time, the finished beer (generally containing 12% or higher alcohol) is sent to the distillation tower (step 314; distilling) to recover the alcohol. The whole stillage from bottom of the distillation tower (step 314) is sent to a fiber separation process (step 333) to remove the fiber, the fiber portion goes to fiber washing process (step 334) to remove/recover protein. After washing, the washed fiber goes to the fiber dewatering process (step 332) to produce low protein and low oil DDG/cellulosic fiber. The liquid from fiber separation (step 333), the fiber washing (step 334) and the fiber dewatering (step 332) are combined to be sent to a high speed disc stack centrifuge (step 331) to break the emulsion bond between the oil and protein in the aqueous phase. The overflow (thin stillage) from disc centrifuge contains most of the oil and emulsion along with soluble compounds and is sent to the evaporator (step 316) and oil recovery (step 317) processes to produce high concentration syrup. Because of higher (6000 to 8000 G) G force on the disc stack centrifuge (step 331), the thin stillage only contains about 1 to 2% insoluble solid by volume. This is substantially better as compared with the overflow (thin stillage) from low G force (3000 to 4000G) fiber separation decanter (step 15) in process 100 of FIG. 1 and the step 215 of process 200 of FIG. 2. The percentage of DS produced by evaporation using the process 300 is normally in the range of 50 to 60% as compared to 30 to 40% DS syrup in the process 100 of FIG. 1 and process 200 of FIG. 2.

[0065] FIG. 4 is a flow diagram of a system for and method of a dry milling process with a backend grinding processes and systems A400 for increasing the alcohol and oil yields in accordance with some embodiments. As shown in the process 400 of FIG. 4, a backend grinding system (step 441, particle size separation) and a particle size reducing device (step 442), a fiber washing process (step 443) and a fiber dewatering process (step 444)) are added to the typical dry mill process 100 of FIG. 1.

[0066] In the process 400, the front-end (process before distillation) is the same as a typical dry mill ethanol process 100 of FIG. 1. The whole stillage from distillation bottom is sent to the particle size separation (step 441) to separate the coarse solids (large fiber, germ, and grit) from fine solids (small diameter protein, yeast), oil, and emulation with soluble materials. The coarse solids are sent to a particle reduce device (step 442) to break down the large germ and grit particle and release the oil, protein and starch. The particle size separation process (step 441) and particle size reduction device step (step 442) are more advanced than the dewatering (step 221) and particle size reduction device (step 222) in process 200 of FIG. 2.

[0067] The paddle machine or any similarly performing screening device can be used in the process for particle size separation (step 441). The screen size normally has a range of between 50 to 300 microns depending on the type of screen (including slotted or round hole) and the purity of the protein meal desired. The germ particles and grit particles are much softer and easier to break after the extensive soak time during fermentation in combination with the heat and violent agitation in the distillation. A wide range of particle reducing devices from high intense grinding mill and to low HP (horse power) consumption roller mill can be used.

[0068] The ground solids from the particle reduce device (step 442) are sent to the fiber washing (step 443) to remove protein, fine germ, and starch using cook water as washing liquid 4431. This washing liquid 4431 picks up the protein, fine germ particle, oil, and starch from the ground fiber and send this valuable material back to the front-end as part of cooking liquid, thus recovering these components during the next round of fermentation batch. The washed fiber is sent to fiber dewatering (step 444) to get dry fiber cake with low protein and low oil, which can be sold as DDG product or further processed to cellulosic ethanol.

[0069] The filtrate from particle size separation (the step 441), which contains fine particles including protein and yeast is sent to the existing protein decanter (the step 435) to recover protein and produce high protein cake. Depending on the protein yield that is needed and the capacity of the protein decanter, the overflow (thin stillage) from the protein decanter normally ranges between 3 to 6% of insoluble suspended solid by volume. This material is sent to the evaporator (the step 416) to produce 40 to 50% DS syrup depending on the type of evaporator and capacity of evaporator. Some of overflow from protein decanter used as backset (e.g., water/solution) to save energy.

[0070] If a higher percentage of DS syrup is needed, the addition of a high speed disc stack type centrifuge (e.g., nozzle centrifuge, desludger centrifuge, and disc decanter) to polish the thin stillage (remove additional suspended solids) to get cleaner thin stillage can be applied, as shown in the process 400A of FIG. 4A.

[0071] FIG. 4A is a flow diagram of a system for and method of a dry milling process with a backend grinding and one-disc centrifuge to polish the thin stillage in accordance with some embodiments.

[0072] In the process 4A, the whole stillage tank can be used as gravity, pre-settling tank to avoid making excess emulation in the down-stream processing step while improving the separation efficiency and obtaining higher oil and protein yields. The whole stillage is transferred from the beer column bottom and goes to the whole stillage tank. This specification provides that the whole stillage tank can be used as a gravity pre-settling vessel (step 445A). The overflow from the whole stillage tank (step 445A) contains mainly oil, emulsified oil, and fine particle size protein. This material is sent to a high-speed disc stack style centrifuge to break the bond between the oil and protein to produce a) overflow containing primarily oil and emulsion, and b) underflow containing primarily protein slurry and decreased oil concentration. The overflow from the disc centrifuge (step 446A) is sent to the evaporator (step 416A) and oil recovery (step 417A) and can produce higher concentration syrup because of the removal of suspended solid particles.

[0073] Insoluble particles are removed by the high-speed, disc style centrifuge which can recover 70 to 90% of the insoluble solid depend on capacity and style of the disc centrifuge. Normally the percent (%) concentration of insoluble solid in thin stillage from a disc centrifuge has a range of 0.6 to 1.2% by volume. Thin stillage with this concentration of insoluble solid can produce 60 to 70% DS syrup in the typical evaporator systems of an ethanol plant. The underflow from the disc centrifuge (step 446A) is sent to a new protein decanter (step 447A) to produce high concentration protein meal, which is enriched in yeast and germ protein.

[0074] The underflow from the whole stillage tank (step 445A) operating in a gravity, pre-settling mode (step 445A) has much higher concentration of coarse solids (large fiber, germ and grit particles) along with some fine protein. This stream can go to particle size separation (step 441A) to preferentially separate fine protein suspended solids and other fine suspended solids from those coarser solids. After separation, the liquid that contains those fine suspended particles (including fine protein solid) is sent to a protein decanter (step 435A) to recover protein and produce one or more high concentration protein meal cakes with between 42 and 55% protein content on a dry matter basis. The overflow from both protein decanters (step 435A and step 447A) is combined with the overflow from whole stillage tank (step 445A) to feed the disc style centrifuge (step 446A). Some overflow from protein decanter (step 447A) is used as backset to save energy. The underflow from coarse particle separation (step 441A) is processed by the particle size reduction device (step 442A).

[0075] After particle size reduction, the fiber washing (step 443A) and fiber dewatering (step 444A) processes produce a low protein and low oil DDG that can be used as animal feed or further processed into cellulosic ethanol using the same process 40 shown in FIG. 4.

[0076] FIG. 4B is a flow diagram of a system for and method of a dry milling process with a backend grinding and two-disc centrifuges in series to polish thin stillage in accordance with some embodiments.

[0077] In order to produce the cleanest thin stillage (lowest suspended solids), which allows one to produce the highest % DS syrup, the use of one additional high speed disc style centrifuge can be used to further polish the thin stillage.

[0078] As shown in a process 400B, the second high speed disc style centrifuge (step 448B) is added to the process 400A (FIG. 4A) to further polish the overflow from first disc style centrifuge (step 446B). The overflows from disc style centrifuge (step 448B) is sent to the evaporator allowing the production of the highest concentrated syrup. The percentages of the insoluble solid by volume in the overflow from the second disc centrifuge (step 448B) is in the range of 0.2 to 0.6% allowing the production of 70 to 80% DS syrup. The rest of process steps in process 400B (FIG. 4B) is the same as those previously shown in process 400A (FIG. 4A) in some embodiments.

[0079] FIG. 4C is a flow diagram of a system for and method of a dry milling process having a backend grinding with a disc decanter in accordance with some embodiments. In some embodiments, the first disc centrifuge (step 446B of FIG. 4B) and second protein decanter (step 447B of FIG. 4B) in process 400B can be replaced by a disc decanter (step 449C) as shown in process 400C of FIG. 4C. A disc decanter uses less electrical energy while providing higher G force and producing cleaner thin stillage. The rest of process steps in process 400C (FIG. 4C) are the same as those previously shown in process 400B (FIG. 4B) in some embodiments.

[0080] The percentage of the insoluble solids in the thin stillage is one of the factors that increases the syrup viscosity. The residual sugars and glycerol present in the syrup increases the syrup viscosity under a high solid concentration. The enriched syrup process (disclosed in the U.S. Patent Application Publication No. 2016/0374364, and titled A METHOD OF AND SYSTEM FOR PRODUCING A HIGH VALUE ANIMAL FEED ADDITIVE FROM A STILLAGE IN AN ALCOHOL PRODUCTION PROCESS, which is incorporated by reference in its entirety for all purposes) can be used to decrease the syrup viscosity by using microorganisms to convert sugar and glycerol present in the syrup to organic acids, including lactic acid.

[0081] FIG. 5 is a flow diagram of a system for and method of a dry milling process with a backend grinding, two-disc centrifuges in series, and a secondary fermentation process and device to produce a high % DS syrup in accordance with some embodiments. As shown in the process 500 (FIG. 5), the enriched syrup (step 551) can be carried out during the evaporation process (step 516). The enriched syrup (step 551) process not only converts sugars and glycerol to organic acids (including lactic acid), it also serves to break the oil/protein/water emulsion, which improves and enhances protein and oil recovery. The rest of process steps in process 500 (FIG. 5) is the same as those previously shown in process 400B (FIG. 4B) in some embodiments.

[0082] Similar to the process 400B (FIG. 4B), the process 500 of FIG. 5 uses a combination of two-disc style centrifuges (step 546B and step 548B) and two protein decanters (steps 535 and step 547) to polish thin stillage before sending to the evaporator (step 516).

[0083] There are several ways to arrange or combine these four steps together. For example: [0084] a) As shown in a process 60 of FIG. 6, the whole stillage is processed through fiber separation (step 641) to remove coarse solids including fiber. The filtrate from the fiber separation (step 641) is processed in the disc style centrifuge (step 646) to produce clean overflow (containing mainly oil and emulsion) for processing in the evaporator (step 616). The underflow from the disc style centrifuge is processed in the protein decanter (step 635) to produce a high protein meal cake. The overflow from the protein decanter 1 (step 635) is processed in disc style centrifuge 2 (step 648) to break up the emulsion bond between oil and protein. The overflow from disc centrifuge 2 (step 648) is primarily oil and some remaining emulsion which is sent back to feed disc style centrifuge 1 (step 646). The underflow from disc centrifuge 2 (step 648) is mainly protein and is sent to protein decanter 2 (step 647) to recover protein. The overflow from protein decanter 2 (step 647) is used as backset to save energy. [0085] b) In the process 60A of FIG. 6A, the whole stillage is processed in the fiber separation process (step 641A). The filtrate from the fiber separation (step 641A) is processed in the disc style centrifuge 1 (step 646A). The overflow, enriched in oil and emulsion, from the disc style centrifuge 1 (step 646A) is processed in the disc style centrifuge 2 (step 648A). The overflow from the disc style centrifuge 2 (step 648A) is processed in the evaporator 616A enabling very high dry solids in the final syrup. The underflow from the disc style centrifuge 1 (step 646A) is sent to the protein decanter 1 (step 635A) to produce a high concentration protein meal cake. The overflow from the protein decanter 1 (step 635A) is recycled back to the disc centrifuge 1 (step 646A). The underflow from disc centrifuge 2 (step 648A) is sent to the protein decanter 2 (step 647A) to recover additional high concentration protein meal cake. The overflow from protein decanter 2 (step 647A) is recycled back to the disc style centrifuge 2 (step 648A) or used as backset to save energy. [0086] c) In the process 60B of FIG. 6B, the beer bottoms are fed to the whole stillage tank (step 645B). In this process the whole stillage tank (step 645B) is used as a gravity pre-settling tank. The overflow from the whole stillage gravity pre-settling tank (step 645B) is enriched in oil and emulsion. This overflow stream is sent to the disc style centrifuge 1 (step 646B). The overflow from disc style centrifuge 1 (step 646B) is sent to disc style centrifuge 2 (step 648B) and the overflow from disc style centrifuge 2 (step 648B) is sent to the evaporator (step 616B). The underflow from disc style centrifuge 1 (step 646B) is sent to protein decanter 1 (step 635B) to produce high concentration protein meal cake. The overflow from protein decanter 1 (step 635B) is recycled back to disc centrifuge 1 (step 646B) as a feed material. The underflow from the disc style centrifuge 2 (step 648B) is sent to a protein decanter 2 (step 647B) to produce high concentration protein meal cake. The overflow from protein decanter 2 (step 647B) is recycled back to disc centrifuge 2 (step 648B) as a feed material. Some of overflow from protein decanter used as backset to save energy.

[0087] A person of ordinary skill in the art appreciates that there are many ways to arrange the two-disc style centrifuges (step x46y and step x48y) and the two protein decanters (step x35y and step x37y) to produce very clean thin stillage for feed to the evaporator while also producing dry, high purity protein cake from whole stillage. The x and y of the x46y, x48, x35, x 37 represent the respective machine and device in a figure, such as x=6 and y=B when the centrifuge is in the FIG. 6B as the centrifuge 646B.

[0088] In some embodiments, the systems and devices are used to produce the cleanest thin stillage with a readily available and reliable centrifuge technology. The very low suspended solid thin stillage allows the production of a very high concentration of a dry matter basis in the syrup. The advantages of producing this very high solids syrup concentration are numerous, including: a) cutting down the dryer load; b) removing as much water as possible in the evaporator to save energy in the operation of the dryer; c) recovering clean water that can be reused in the ethanol process thereby reducing input water demand; d) producing a very high syrup concentration, (e.g., 80% DS). The syrup can bypass the dryer entirely allowing the maximum syrup concentration to be added after the dryer; e) avoiding sending the syrup to the dryer, which allows the avoidance of heat sensitive nutrient and probiotic in syrup to be damaged by the high temperatures that are often experienced in the distiller's dryers; and (f) when syrup is dry enough to bypass the dryer, the load on an existing dryer system is substantially reduced. This creates the possibility of modifying the typical two drum dryers in series to become two drum dryers working in parallel operation. This allows for one dryer to now produce DDG (low protein feed) and the other dryer to produce a high protein meal. This advantage allows an existing facility to diversify their products without the substantial capital spending for new dryers.

[0089] In some embodiments, the process 700 of FIG. 7 is applied to a two-drum dryer that has been modified to operate in parallel into the process 50 (FIG. 5). This process produces a substantially enhanced and more efficient dry milling ethanol process for the typical dry mill industry. In the process 700 of the FIG. 7, the whole stillage is fed to the whole stillage tank (step 745), which is used as gravity, pre-settling tank (step 745A). The overflow from the pre-settling whole stillage tank (step 745A) is fed to the disc style centrifuge 1 (step 746) to break the bond/interactions forming undesired emulsion between oil and protein. The overflow from disc style centrifuge 1 (step 746) is enriched in oil and emulsion with small amounts of fine suspended particles (including protein). This overflow is sent to the disc style centrifuge 2 (step 748) to polish and remove many of the fine suspended particles, including protein. The overflow from disc style centrifuge 2 (step 748) is sent to the evaporator (step 716). A semi-concentrated syrup, around 20 to 40% of DS, is processed through the common oil recovery processes (step 717) to recover and enriched syrup (step 751) to convert organic materials, including sugars and glycerol to organic acids, including lactic acid. This conversion to organic acids decreases the syrup viscosity. The final syrup concentration produced by the evaporator can reach 80% of DS or more with this process. The underflow from the whole stillage tank (step 745) is processed through the particle size separation operation (step 741). The underflow from the particle size separation (step 741) is directed to the particle size reduction device (step 742). The material exiting the particle size reduction (step 742) is processed through the fiber washing (step 743) to wash out fine particles including germ and grit particles.

[0090] These recovered fine particles are recovered with cook water which will be returned to the front-end of the ethanol plant. This washing liquid which now contains fine germ and grit particles is sent back to the front of the plant, which results in the increase in alcohol, oil, and protein yield. The washed cake from the fiber washing (step 743) process is sent to a fiber dewatering (step 744) to produce dry DDG cellulose cake. This cellulose cake can be further processed into cellulosic ethanol. The liquid from the fiber dewatering step is recycled to the fiber washing (step 743) to recover more valuable fine particles from the ground fiber. The filtrate from the particle size separation (step 741) process is processed in the protein decanter 1 (step 735) to produce a high purity protein cake. The overflow from the protein decanter 1 (step 735) is combined with the underflow from disc style centrifuge 2 (step 748) and the overflow from protein decanter 2 (step 747) to the disc style centrifuge 1 (step 746) or used as backset to save energy. The protein cake from protein decanter 1 (step 735) and protein decanter 2 (step 747) is sent to a protein dryer (step 771) to produce a high protein meal with up to 50% protein content and a yield of up to 6 lb./Bu protein meal. The fiber cake from the fiber dewater process (step 44) is directed to the DDG dryer (step 772). The enriched syrup can be added to the DDG dryer before, during, or after the dryer has finished drying the DDG. The addition of enriched syrup produces enriched DDGS with high organic acid concentration, such as lactic acid, along with probiotic character high protein meal. In some embodiments, a small portion of the enriched syrup is added to the protein meal to produce an enriched protein meal with high organic acid, such as lactic acid and probiotic character.

[0091] In some embodiments, the process 700A of FIG. 7A is adding the whole stillage feed directly to particle size separation (step 741A) and rest of the process steps in process 700A is same as process 700 in FIG. 7 in some embodiments. Two disc centrifuge conjunction with two decanter centrifuge will produce cleanest thin stillage with less than 0.5% solid by volume and produce 80% DS or more syrup.

[0092] The process and system disclosed herein can start from using whole stillage, which is produced at the distillation step (e.g., separated by a fiber separation process, such as the step 15 of FIG. 1). In some embodiments, the whole stillage includes the insoluble solids (wet cake.) The liquid from the distillation step (e.g., separated by a fiber separation process, such as the step 15 of FIG. 1) is referred to as thin stillage.

[0093] The backend grinding system as shown in FIG. 4, is disclosed in the patent (U.S. Pat. No. 9,388,475, is titled SYSTEM FOR AND METHOD OF SEPARATING OIL AND PROTEIN FROM GRAINS USED FOR ALCOHOL PRODUCTION which is incorporated by reference in its entirety for all purposes).

[0094] To be succinct, not all the process and steps are repeated in the descriptions. For example, each and every step described in FIGS. 1 to 4 are able to be entirely or selectively applied to any of the figures herein. Each of the processes and steps disclosed herein can be selected to be performed or omitted.

[0095] In utilization, the process is used to make a high syrup concentration using a dry mill process.

[0096] In operation, the whole stillage from the distiller is going through the dry mill process with advanced features including a) a backend grinding to increase alcohol, oil, and protein yield, b) two-disc centrifuges in series to produce cleanest thin stillage, c) a secondary fermentation to produce enriched syrup with the highest % DS syrup, d) splitting two dryers in series to two dryers in parallel to produce high protein meal and enriching low protein feed to improve the syrup concentration.

[0097] While the present invention has been illustrated by a description of various embodiments and while these embodiments have been described in considerable detail, it is not the intention of the applicant to restrict or in any way limit the scope of the appended claims to such detail. For example, although the various systems and methods described herein have focused on corn, virtually any type of grain, including, but not limited to, wheat, barley, sorghum, rye, rice, oats and the like, can be used. The purified fiber, often called white fiber, can be used for a number of applications including for the paper industry or as feed stock for secondary (cellulosic) alcohol production. Thus, the invention in its broader aspects is therefore not limited to the specific details, representative apparatus and method, and illustrative example shown and described. Accordingly, departures may be made from such details without departing from the spirit or scope of applicant's general inventive concept.

[0098] The present invention has been described in terms of specific embodiments incorporating details to facilitate the understanding of principles of construction and operation of the invention. Such reference herein to specific embodiments and details thereof is not intended to limit the scope of the claims appended hereto. For example, the disc centrifuge can be a nozzle centrifuge, a desludging centrifuge, disc decanter, sedicanter or other suitable high g centrifuge device as may be available today or in the future. The particle size reduce device can be disk grinding mill, roller mill, collider mill, pin mill or any other type of suitable milling equipment. It will be readily apparent to one skilled in the art that other various modifications may be made in the embodiment chosen for illustration without departing from the spirit and scope of the invention as defined by the claims.