WO2014182807A1

WO2014182807A1 - Combination corn and sugar cane processing plant and systems and processes for producing alcohol thereat

Info

Publication number: WO2014182807A1
Application number: PCT/US2014/037138
Authority: WO
Inventors: John KWIK
Original assignee: Fluid Quip Process Technologies, Llc
Priority date: 2013-05-07
Filing date: 2014-05-07
Publication date: 2014-11-13
Also published as: ZA201508218B; BR112015028100A2; BR112015028100B1; MX2015015474A

Abstract

A combination corn and sugar cane processing plant and systems and processes for producing alcohol thereat is disclosed. An existing sugar cane processing plant, which can produce sugar and/or alcohol from sugar cane, may be retrofitted, so as to allow for simultaneous processing of other feedstocks, such as corn, for alcohol production, without significant changes to the existing sugar cane process equipment and line or significant capital investment. Alternatively, the combination corn and sugar cane processing plants may be constructed from the ground up, if so desired. Such processing plants can separately but simultaneously process front end sugar cane and corn streams, which converge to share the same fermentation and/or distillation and back end equipment for alcohol and other optional byproduct production. In one example, corn fiber can be removed prior to fermentation so as to allow sugar cane and additional raw materials containing insolubles to be co-currently processed.

Description

Combination Corn and Sugar Cane Processing Plant and

Systems and Processes for Producing Alcohol Thereat

Technical Field

[0001] The present invention relates to a combination corn and sugar cane processing plant and to systems and processes for producing alcohol thereat.

Background

[0002] Alcohol production requires fermentation of sugars by yeast at processing plants, such as corn or sugar cane processing plants, to produce alcohol, such as ethanol, which is then distilled to produce, for example, high purity ethanol. There are generally two types of alcohol plants: (1) those that provide a pure sugar stream to fermentation or (2) those that provide the sugar in-situ with other insoluble solids to the yeast.

[0003] Sugar cane plants generally provide a pure sugar stream by either pressing sucrose or digesting sucrose out of sugar cane, for example. The sugar cane sucrose can then be concentrated, refined, and sold as table sugar for human consumption, for example, and/or utilized to produce alcohol, such as ethanol. An un-purified sugar stream can also be used for ethanol production. The remaining sugar biomass byproduct, referred to as bagasse, may be burned in boilers to produce energy to help operate the ethanol plant.

[0004] To that end, Fig. 1 represents a general flow diagram of a typical refined sugar/alcohol production system and process 10 in which sugar cane can be processed to produce refined sugar and/or alcohol, such as ethanol. Before production, sugar cane must first be harvested and taken to the processing plant. Harvest times tend to be during the dry season and the length of the harvest can range from as little as 2-3 months up to about 11 months. Once at the plant, the harvested sugar cane is typically subjected to a milling step 12 whereat the sugar cane is milled to extract the cane juice from the cane fiber. Here, the cane can be crushed and/or cut in a series of large roller or mills and/or with rotating knives. Extraction can be conducted as a counter-current process using fresh hot water at one end, which is pumped in the opposite direction to the sugar cane. More water typically yields more sugar, but this creates a more dilute juice and, thus, more energy is required to evaporate the juice. A typical juice from extraction will contain perhaps 15% sugar and the residual fiber, or bagasse, will contain 1% to 2% sugar, about 50% moisture, and "ash".

[0005] After water is added to produce a diluted juice or sugar cane slurry stream, the sugar cane slurry stream can be subjected to a separation step 16 whereat a diffuser, for example, may be used to clean the extracted juice by separating it from the cane fiber. The separated cane fiber, referred to now as bagasse, may be further milled and eventually used in an energy production step 14 whereat the bagasse can be burned in large furnaces in the plant, for example, which can be used to boil water and generate high pressure steam and electricity. A typical cane might contain 12 to 14% fiber which, at 50% moisture content, gives about 25 to 30 tons of bagasse per 100 tons of cane or 10 tons of sugar.

[0006] After the bagasse is separated out, the sugar cane slurry stream also may be further subjected to a cleaning step 16 whereat the sugar cane slurry stream can be cleaned or purified, such as with slaked lime, which can settle out dirt leftover from the sugar cane field. The cleaned sugar cane slurry stream then can be further processed for refined sugar production and/or alcohol production, as is discussed next.

[0007] For refined sugar production, the sugar cane slurry stream can be thickened into a syrup, called molasses, at evaporation step 18 by boiling off water in the stream using steam. Sometimes the syrup is cleaned again but more often it goes to the crystal-making step 19 without any more cleaning. The syrup from the evaporation step 18 also may be sent directly to a fermentation step 20 to produce alcohol, which is discussed below. With the crystal-making step 19, the syrup can be placed into a large pan for boiling whereat more water is boiled off until conditions are desirable for sugar crystal growth. Additional sugar may need to be added to initiate crystal formation. Once the crystals have grown, the resulting mixture of crystals and any remaining molasses can be spun in centrifuges, for example, to separate the two. The crystals are further dried before being stored and refined sugar, such as table sugar, is ready for dispatch. The sweet molasses by-product from the crystal making step 19 may be further subjected to fermentation to produce alcohol.

[0008] For alcohol production, the cleaned sugar cane juice, which defines a sugar cane slurry stream, as well as the molasses byproduct, which may be diluted with water to provide a sugar cane slurry stream as well, can be sent to fermentation step 20 to convert the sugars therein to alcohol, followed by a distillation step 22, which recovers the alcohol. Fermentation may be assisted by yeast addition, which can be recovered and recycled for use again in the fermentation step 20. Typically, only about 90% of yeast is actually recycled, with the remainder being unrecovered or lost in the process. The fermented solution (referred to here as "fermented wine") can be separated from non-fermented byproduct, referred to here as the vinasse. The vinasse byproduct may be sent to a retention or holding pond 24 for use in irrigating sugar cane fields or can be further processed, such as dehydrated, and may be used as fertilizer or sold to farmers for animal feed. It should be understood that the syrup from the evaporation step 18 may be apportioned such that equal or unequal portions can go to both sugar and alcohol production or all may be sent to sugar production or alcohol production, as desired. Of course, sugar cane processing plants may be set up for only sugar production whereas others may be set up for only alcohol production. [0009] Concerning corn wet mill plants, these plants, like sugar cane plants, also generally produce a purified starch stream but generally only after separating fiber, protein, and germ components of the corn kernel from a starch slurry. The starch slurry, or stream, is then converted to simple sugars to use in fermentation for alcohol production.

[00010] In contrast to the above, dry-grind corn mill plants (and wheat processing plants, for example) generally produce a ground corn slurry or corn slurry stream with all solids present. This slurry stream is subjected to liquefaction to convert starches to sugars, which is commonly sent to fermentation and distillation, with all kernel components present. These in-situ feed stocks typically are processed through fermentation and distillation for alcohol production, with insoluble solids at over 20% by weight on a dry basis and with many particles over 1 mm in size.

[00011] To that end, Fig. 2 represents a flow diagram of a typical dry grind ethanol production system and process 50. The system and process 50 begins with a milling step 52 in which dried whole corn kernels are passed through hammer mills for grinding into meal or a fine powder. The screen openings in the hammer mills typically are of a size 7/64, or about 2.78 mm, with the resulting particle distribution yielding a very wide spread, bell type curve, which includes particle sizes as small as 45 micron and as large as 2 to 3 mm.

[00012] The milling step 52 is followed by a liquefaction step 56 whereat the ground meal is mixed with cook water to create a slurry and a commercial enzyme called alpha-amylase is typically added (not shown). The pH is adjusted here to about 5.0 to 6.0 and the temperature maintained between about 50°C to 105°C so as to convert the insoluble starch in the slurry to soluble starch. The stream after the liquefaction step 56 has about 30-34% dry solids (DS) content with all the components contained in the corn kernels, including sugars, protein, fiber, starch, germ, grit, and oil and salts, for example. There generally are three types of solids in the liquefaction stream: fiber, germ, and grit, with all three solids having about the same particle size distribution.

[00013] The liquefaction step 56 is followed by a simultaneous saccharification and fermentation step 58. This simultaneous step is referred to in the industry as "Simultaneous Saccharification and Fermentation" (SSF). In some commercial dry grind ethanol processes, saccharification and fermentation occur separately (not shown). Both individual saccharification and SSF can take as long as about 50 to 60 hours. Fermentation converts the sugar to alcohol using a fermentor and yeast. Ethanol produced from sugar cane, as compared to corn, for example, tends to be cheaper to process because it does not need to make the transformation from carbohydrates/starches to sugars before fermented to make ethanol. The yeast may optionally be recovered from the fermented stream prior to distillation and recycled for re-use at fermentation step 58. Subsequent to the saccharification and fermentation step 58 is the distillation (and dehydration) step 64, which utilizes a still or distillation unit to recover the alcohol.

[00014] Distillation 64 is followed by a centrifugation step 66, which involves centrifuging the residuals, i.e., "whole stillage", produced with the distillation step 64 to separate the insoluble solids ("wet cake") from the liquid ("thin stillage"). The "wet cake" includes fiber, of which there are three types: (1) pericarp, with average particle sizes typically about 1 mm to 3 mm; (2) tricap, with average particle sizes about 500 micron; (3) and fine fiber, with average particle sizes of about 250 micron. The liquid from the centrifuge contains about 6% to 8% DS.

[00015] The thin stillage enters evaporators in an evaporation step 68 to boil away moisture, leaving a thick syrup that contains the soluble (dissolved) solids from fermentation (25% to 40% dry solids). The concentrated slurry may be subjected to an optional oil recovery step 69 whereat the slurry can be centrifuged to separate oil from the syrup. The oil can be sold as a separate high value product. The oil yield is normally about 15.7 kg/metric ton to about 23.6 kg/metric ton of corn with high free fatty acids content. This oil yield recovers only about ¼ of the oil in the corn. About one-half of the oil inside the corn kernel remains inside the germ after the distillation step 64, which cannot be separated in the typical dry grind process using centrifuges. The free fatty acids content, which is created when the oil is held in the fermenter for approximately 50 hours, reduces the value of the oil. The (de-oil) centrifuge only removes less than 50% because the protein and oil make an emulsion, which cannot be satisfactorily separated.

[00016] The centrifuged wet cake and the syrup, which has more than 10% oil, can be mixed and the mixture may be sold to beef and dairy feedlots as Distillers Wet Grain with Soluble (DWGS). Alternatively, the syrup can be mixed with the wet cake, then the

concentrated syrup mixture may be dried in a drying step 70 and sold as Distillers Dried Grain with Soluble (DDGS) to dairy and beef feedlots. This DDGS has all the protein and 75%> of the oil in corn. But the value of DDGS is low due to the high percentage of fiber, and in some cases the oil is a hindrance to animal digestion.

[00017] The equipment, systems, and plants for processing sugars in-situ with all solids present are designed quite differently than those designed to process pure sugar streams. Mainly, in sugar cane processing plants, fermentation and distillation is designed for minimal insoluble solids, which tend to be of a small size (e.g., typically no greater than 150 microns). While this works well for sugar cane applications, it limits the ability of sugar cane plants, such as sugar cane ethanol plants, to accept other feedstocks, such as corn for ethanol production without significant changes to the process equipment and line, and significant capital investment. As such, a major drawback of sugar cane plants, such as those in Brazil, is that they are only really able to process sugar cane.

[00018] Another drawback to utilizing sugar cane is that the sugar content in the cane varies from about 12% in the beginning and end of the growing season (April and November) up to about 18% at the height of the season (July and August). To maximize production, plants are designed with equipment to process at the maximum sugar content. Sugar cane ethanol plants that produce approximately 105 million liters per year can have a capital construction cost from $135 to $179 Million Brazilian Real. These are very high-cost assets that can only be utilized at their maximum yield capabilities for 2 to 3 months a year and are limited to operating for about 8 months of the year. The table below illustrates Raw Sugar Production per Month for an average Sugar Cane Ethanol plant. Because table sugar is the primary product, production of raw table sugar is maximized and the sugar stream for ethanol production is sacrificed.

RAW SUGAR PRODUCTION-MONTHLY SUMMARY

[00019] It would be beneficial to have sugar cane plants maximize ethanol production year round, such as by devising a system and process that allows existing or new sugar cane ethanol plants to accept or utilize other feedstocks, such as corn. To that end, some in the industry have explored co-locating dry-grind corn ethanol production at sugar cane ethanol plants to use some of the infrastructure in the off-season, but generally these have been focused on simply using the utilities, ethanol storage, and load-out systems in place at the sugar cane facilities, with all other unit operations being of brand new construction. Such systems only operate when no sugar cane ethanol production is taking place to isolate the solids stream so as to avoid significant modifications to the distillation system or a dedicated distillation system, which would increase the capital requirement. And even with these modifications, overall plant production would still be limited during the low % sugar months.

[00020] If a complete, stand alone corn dry mill processing line, with dedicated fermenters, distillation, whole stillage dewatering decanters, and thin stillage evaporators, for example, was constructed to maximize ethanol storage and load-out and transportation systems in place at an existing sugar cane facility, it could operate year-round, but would have the same problem of having to turn-down the corn ethanol plant during the sugar cane harvest months and shut down during the sugar cane mill peak production. Such a co-location corn production process also fails to recognize and utilize the distillation and co-generation opportunities at hand.

[00021] Finally, the major by-product from corn ethanol production is Distillers Dry

Grains (DDGS), which is an animal feed product that contains the fiber, protein, and fat remaining after the production process. In order to generate power to operate most sugar cane facilities, a by-product must be burned in boilers to produce energy. Burning DDGS is not desirable due to all of the components therein and its feed value would be lost.

[00022] Accordingly, it would be beneficial to provide a combination corn and sugar cane processing plant and a system and process for producing alcohol thereat that can overcome one or more of the aforementioned drawbacks.

Summary

[00023] The present invention relates to a combination corn and sugar cane processing plant and to systems and processes for producing alcohol thereat. [00024] With respect to combination corn and sugar cane processing plants, in one example, an existing sugar cane processing plant, which can produce sugar and/or alcohol from sugar cane, may be retrofitted, so as to allow for simultaneous processing of other feedstocks, such as corn, for alcohol production, without significant changes to the existing sugar cane process equipment and line or significant capital investment. Alternatively, the combination corn and sugar cane processing plants may be constructed from the ground up, if so desired.

[00025] For retrofitting sugar cane processing plants, such a system and process, for example, may utilize at least the current sugar cane fermentation, distillation, water purification, ethanol storage and loadout, and energy co-generation equipment at the sugar cane ethanol plant, with minimum or no modifications required to the existing systems. Such processing plants can separately but simultaneously process front end sugar cane and corn streams, which converge to share the same fermentation and/or distillation and back end equipment for alcohol and other optional byproduct production. Such a setup, which is further discussed in detail hereinbelow, can allow the combination corn and sugar cane processing plant to operate at maximum ethanol production, both in and out of sugar cane season ("safra" and "intra-safra", respectively), with minimum capital investment. In addition, high-value co-products can be recovered from the incoming raw material prior to fermentation, such as oil and fiber, as well as post distillation, such as protein and additional oil.

[00026] In one embodiment, a system for producing ethanol from sugar cane and corn is provided, which includes a first milling device that mills corn kernels into corn flour, and a second milling device that separately mills sugar cane to extract sugar cane juice. In addition, a first slurry tank is provided in which the com flour mixes with a liquid to produce a corn slurry stream including free oil, germ, protein, starch, and fiber, along with a second slurry tank in which the sugar cane juice mixes with a liquid to produce a sugar cane slurry stream including sugar. At least one holding tank aids in converting the starch to sugar and a dewatering device separates the fiber from the corn slurry stream prior to fermentation. Also, a first fermentor in which sugars from the corn slurry stream are fermented and a second fermentor in which sugars from the sugar cane slurry stream are separately fermented to produce alcohol are provided, along with at least one distillation device whereat the alcohol is recovered from combined fermented corn slurry and sugar cane streams. Or alternatively, at least one fermentor is provided whereat sugars from the corn slurry stream and the sugar cane slurry stream are fermented together, along with a distillation device whereat the alcohol is recovered from the fermented sugars.

[00027] In another embodiment, a method for converting a sugar cane processing plant into a combination sugar cane and corn processing plant for alcohol production is provided, which includes incorporating into an existing sugar cane processing plant a separate front end corn alcohol production process, which includes a milling device, a liquefaction system, and a front end dewatering device that separates fiber from a corn slurry stream prior to fermentation of the corn slurry stream. Then, no later than distillation but after fiber separation of fiber from the corn slurry stream, separate corn slurry and sugar cane slurry streams, including sugars for alcohol production and recovery, are combined together. In one example, the front end corn alcohol production process is a front end dry corn dry grind alcohol production process.

[00028] In another embodiment, a process for producing alcohol from sugar cane and corn is provided and includes separately milling corn kernels into corn flour and sugar cane to extract sugar cane juice. The process further includes separately mixing the corn flour and the extracted sugar cane juice with a liquid to produce separate corn and sugar cane slurry streams, the corn slurry stream including free oil, germ, protein, starch, and fiber and the sugar cane slurry stream including sugar. Then, prior to fermentation, the starch is converted to sugar and the fiber separated from the corn slurry stream. And thereafter either, the sugars from the corn slurry stream and the sugar cane slurry stream are separately fermented to produce alcohol, then the fermented sugars are combined and distilled to recover the alcohol, or the sugars from the corn slurry stream and the sugar cane slurry stream are combined and the sugars fermented together to produce alcohol, then the fermented sugars are distilled to recover the alcohol.

[00029] In one example, corn fiber can be removed prior to fermentation so as to allow sugar cane and additional raw materials containing insolubles to be co-currently processed without modification to the existing sugar cane fermentation and distillation systems. In another example, residual sugars can be recovered from the stillage post distillation, a portion of which can be returned to the cook section to allow for capture of the residual sugars.

[00030] In addition, the combination corn and sugar cane processing plants can have the ability to receive high moisture feed stocks without loss of yield and can receive high moisture feed stock to reduce thermal consumption required to dry incoming grain. Also, emissions can be reduced in the boiler by providing a cleaner feed stream with minimum protein and oil composition. And ethanol concentrations in the beer feed on a weight percentage can be increased as a blended beer stream can contain a higher percentage of alcohol compared to existing sugar cane slurry streams. Such a higher ethanol concentration can increase the existing distillation capacity with no modifications or capital requirement, and can significantly decrease the thermal requirements for distillation.

[00031] Yet, another aspect of the combination corn and sugar cane processing plants is the ability to incorporate co-product production opportunities of corn fractionation systems and improve/modify them so as to provide desirable combination corn and sugar cane processing plants that utilize sugar from sugar cane and starch from corn to co-ferment and distill ethanol and produce additional co-products.

Brief Description of the Drawings

[00032] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, with a detailed description of the embodiments given below, serve to explain the principles of the invention.

[00033] Fig. 1 is a flow diagram of a typical sugar cane ethanol/sugar production system and process;

[00034] Fig. 2 is a flow diagram of a typical corn dry grind ethanol production system and process;

[00035] Fig. 3 is a basic flow diagram of a system and process for processing alcohol simultaneously from sugar cane and corn at a combination corn and sugar cane processing plant in accordance with an embodiment of the invention;

[00036] Fig. 3A is a variation of the basic flow diagram of Fig. 3 showing a system and process for processing alcohol simultaneously from sugar cane and corn at a combination corn and sugar cane processing plant in accordance with another embodiment of the invention;

[00037] Figs. 4A is a flow diagram of the front end of a system and process for processing alcohol simultaneously from sugar cane and corn in accordance with an embodiment of the invention showing only the corn slurry stream;

[00038] Fig. 4B is a continuation of the flow diagram of Fig. 4A showing the back end of a system and process for processing alcohol simultaneously from sugar cane and corn in accordance with an embodiment of the invention; [00039] Figs. 5 A is a flow diagram of the front end of a system and process for processing alcohol simultaneously from sugar cane and corn in accordance with an embodiment of the invention showing only the corn slurry stream; and

[00040] Fig. 5B is a continuation of the flow diagram of Fig. 5 A showing the back end of a system and process for processing alcohol simultaneously from sugar cane and corn in accordance with an embodiment of the invention.

Detailed Description

[00041] The present invention is directed to a combination corn and sugar cane processing plant and to systems and processes for producing alcohol thereat.

[00042] Figs. 1 and 2 have been discussed above and represent a flow diagram of a typical sugar cane ethanol/sugar production system and process 10 and a typical corn dry grind ethanol production system and process 50, respectively. Also, as a general reference point, the alcohol or ethanol production system and processes, as described herein, can be divided into a front end and a back end. The part of the system and process that occurs prior to distillation is considered the "front end", and the part of the system and process that occurs after distillation is considered the "back end".

[00043] Figs. 3-5B illustrate various embodiments of a system and process for processing alcohol simultaneously from sugar cane and corn via a combination corn and sugar cane processing plant for improving alcohol, oil and/or protein yields, for example. These systems and processes are discussed in detail herein below.

[00044] Specifically, and with reference now to Fig. 3, at a combination corn and sugar cane processing plant, a system and process for alcohol production 100 can separately include, or have had separately incorporated therein, in the front end, a corn dry grind ethanol system and process 102, which may be modeled after the front end of the system and process 50 as shown in Fig. 2, with at least one exception, which includes front end separation of fiber from the corn slurry stream prior to fermentation, as shown at numeral 104, i.e., fiber separation step 104. In particular, a dewatering device , e.g., a paddle screen, vibration screen, filtration centrifuge, pressure screen, screen bowl decanter and the like, can be used at the fiber separation step 104 to accomplish separation of the fiber from a liquid portion. One exemplary dewatering device for the fiber separation step 104 is shown and described in Lee U.S. Patent Application Publication No. 2010/0012596, the contents of which are incorporated herein by reference in its entirety. The system and process for alcohol production 100 also includes a front end refined

sugar/alcohol production system and process 104, which may be modeled after the front end of the system and process 10 as shown in Fig. 1, in which sugar cane can be processed to produce alcohol or sugar and alcohol, such as ethanol. In this example and herein throughout, refined sugar production for the recovery of refined sugar is optional.

[00045] As shown in Fig. 3, with fiber separated from the corn slurry stream and after fermentation steps 20 and 58, respectively, each of the fermented sugar cane and corn slurry streams can be combined for alcohol recovery at distillation step 1 10. In particular, beer from the corn fermentors at fermentation step 8 can be sent to distillation feed tanks or units at distillation step 1 10 to be combined with the wine from the sugar cane fermentors at fermentation step 20, which can occur after yeast separation and recycling (not shown). Here, the ethanol portion (e.g., 200 proof ethanol) can be distilled from the mixed beer/wine feed stream. Since excess fermentation capacity exists in most current sugar cane mills, this capacity could be utilized to ferment a newly incorporated corn slurry stream, with the sugar cane slurry stream being fermented co-currently but in separate fermentors. In contrast, if optional recovery of yeast from the fermented corn slurry stream and/or the fermented sugar cane slurry stream is not necessarily desired, the corn slurry stream, with its fiber separated therefrom, and the sugar cane slurry stream, as is shown in Fig. 3A, can be directly combined for fermentation of the sugars at fermentation step 112 for alcohol production, subsequently followed by distillation step 1 10 for recovery of the alcohol.

[00046] In another embodiment, each of the fermented sugar cane and corn slurry streams can remain separate and sent to separate distillation units for alcohol recovery at distillation step 1 10. In particular, beer from the corn fermentors at fermentation step 58 and wine from the sugar cane fermentors at fermentation step 20 can be sent to separate distillation feed tanks or units at distillation step 1 10, with the resulting corn and sugar cane stillage being combined after distillation for further processing, as desired and as described herein. In yet another

embodiment, beer from the corn fermentors at fermentation step 8 and wine from the sugar cane fermentors at fermentation step 20 can be sent to separate beer columns of the distillation feed tanks or units at distillation step 110. The resulting corn and sugar cane stillage can be combined thereafter for further processing, as desired and as described herein, and the overhead from the beer columns can be combined for further rectification for alcohol recovery. In other words, the streams are kept separate for only part of the distillation step 1 10.

[00047] With further reference now to both Figs. 3 and 3A, the back end of the system and process for alcohol production 100 and 100A, in one embodiment, may be generally modeled after that of the back end of the refined sugar/alcohol production system and process 10 as shown in Fig. 1. Here, at the distillation step 110, the fermented solution is separated from non- fermentables called stillage, which can include fine fiber, protein, and additional oil, for example, to produce the alcohol. The thin stillage may be sent to retention or holding pond 1 14 for use in irrigating sugar cane fields or can be further processed, such as dehydrated, and may be used as fertilizer or sold to farmers for animal feed. With the separation of the insoluble fiber fraction from the corn slurry stream, existing sugar cane distillation systems would essentially require no modifications to accept the corn beer stream. Such a setup also would allow sugar cane production plants to operate at maximum ethanol production in season and out of season with minimum capital investment.

[00048] With further reference now to Fig. 4A, this figure depicts, at a combination corn and sugar cane processing plant, a system and process for alcohol production 200 that can separately include, or have had separately incorporated therein, in the front end a corn dry grind ethanol system and process 201 in accordance with an embodiment of the invention. The system and process for alcohol production 200 also includes a front end refined sugar/alcohol production system and process 202 (generically represented), which may be modeled after the front end of the system and process 10 as shown in Fig. 1, in which sugar cane can be processed to produce alcohol or sugar and alcohol, such as ethanol.

[00049] With respect to the front end corn dry grind ethanol system and process 201, as shown in Fig. 4 A, raw corn is first subjected to a milling step 203, which involves use of a hammer mill, or the like, to grind corn to particle sizes less than about 7/64 inch (or about 2.78 mm) and allow for the release of starch and oil therefrom. In one example, the screen size for separating the particles can decrease from about 7/64 inch (2.78 mm) to about 5/64 inch (1.98 mm). In another example, the particle sizes are from about 50 micron to 3 mm. The grinding helps break up the bonds between the fiber, protein, starch, and germ and expose the starch for hydration. In one example, the combination corn/sugar cane processing plant can process corn up to 25%-30% moisture, whereas current milling technology can only generally handle corn moistures up to 17-18% moisture before significant yield loss occurs.

[00050] Next, at slurry tank 204, the ground corn flour is mixed with a liquid, such as recycled filtrate from a step later in the process, as described further below, to create a slurry and begin liquefaction at liquefaction step 206. Fresh water and/or additional back set liquid from the back end of the process, as further described below, may also or alternatively be added here. An enzyme(s), such as alpha amylase, optionally can be added to the slurry tank 204 such as to assist in converting insoluble starch in the slurry to soluble starch. The slurry may be heated at the slurry tank 204 to about 150°F to about 200°F for about 30 minutes to about 120 minutes. It should be understood that other temperatures may be suitable for beginning liquefaction, including lower or higher temperatures. The stream from the slurry tank 204 contains about 1 lb/bu (39 kg/metric ton) free oil and about 1.5 lb/bu (59 kg/metric ton) germ (particle size ranges from about 50 micron to about 3 mm), 1.8 lb/bu (71 kg/metric ton) grit (particle size ranges from about 50 micron to about 3 mm), and 4.2 lb/bu (165 kg/metric ton) fiber (particle size ranges from about 50 micron to about 3 mm).

[00051] After the slurry tank 204, there are normally three options at liquefaction step

206, which may be selected depending generally upon the desired temperature and holding time of the slurry. With option one, the slurry from the slurry tank 204 can be fed to a jet cooker, heated to 120°C, held in a retention tank or tube for about 5 to 30 min., then forwarded to a flash tank. The jet cooker creates a sheering force that ruptures the starch granules to aid the enzyme in reacting with the starch inside the granule. With option two, the slurry can subjected to a secondary slurry tank whereat steam is injected directly thereto and the slurry is maintained at a temperature from about 90°C to 100°C for about 30 min to one hour. With option three, the slurry from the slurry tank 32 is sent to a secondary slurry tank, without any steam injection, and maintained at a temperature of about 80°C to 90°C for 1 to 2 hours. Thereafter, the slurry from the either of the options is forwarded to one or more holding tanks for a total holding time of about 2 to 4 hours at temperatures of about 80°C to 90°C to complete the liquefaction step 206. It should be understood that the temperatures may be adjusted higher or lower, as desired, for obtaining satisfactory liquefaction of the corn slurry stream. In one example, the temperature can be room temperature, e.g., 20°C, or higher. In another example, the temperature can be 50°C or higher. Various enzymes (and types thereof) such as amylase or glucoamylase, fungal, cellulase, cellobiose, protease, and the like can be optionally added during the liquefaction step 206 to assist in converting insoluble starch in the slurry to soluble starch and enhance the separation of components, such as to help break the bonds between protein, starch, and fiber.

[00052] The corn slurry stream from the liquefaction step 206 is next subjected to a first liquid/solid separation step 208. The first liquid/solid separation step 208 separates a generally liquefied solution (about 60-80% by volume), which includes free oil, protein, starch, and fine solids (which do not need grinding), from heavy solids cake (about 20-40% by volume), which includes the heavier fiber, grit, and germ, which can include bound oil, protein, and/or starch. The first liquid/solid separation step 208 uses a dewatering device, e.g., a paddle screen, a vibration screen, screen decanter centrifuge or conic screen centrifuge, a pressure screen, a preconcentrator, and the like, to accomplish separation of the solids from the liquid portion. In this way, the fiber can be separated from the corn slurry stream prior to fermentation, similar to that which is generally depicted by fiber separation step 104 in Figs. 3 and 3 A. In one example, the fine solids are no greater than about 150 microns. In another example, the fine solids are no greater than 500 microns, which is generally dependent upon the screen size openings used in the liquid/solid separation device(s).

[00053] In one example, the dewatering device is a paddle screen, which includes a stationary cylinder screen with a high speed paddle with rake. In one example, the number of paddles on the paddle screen can be in the range of 1 paddle per 4 to 8 inches (10 to 20 cm) of screen diameter. In another example, the dewatering device is a preconcentrator, which includes a stationary cylinder screen with a low speed screw conveyor. The conveyor pitch on the preconcentrator can be about 1/6 to 1/2 of the screen diameter. The number of paddles on the paddle screen and the conveyor pitch on the preconcentrator can be modified depending on the amount of solids in the feed. In one example, the gap between the paddle screen and paddle can range from about 0.04 to 0.2 inch (1.0 to 0.5 mm). A smaller gap gives a drier cake with higher capacity and purer fiber but loses more fiber to filtrate. A larger gap gives a wetter cake with lower capacity and purer liquid (less insoluble solid). The paddle speed can range from 400 to 1200 RPM. In another example, the paddle speed can range from 800 to 900 RPM. A higher speed provides higher capacity but consumes more power. One suitable type of paddle screen is the FQ-PS32 or the FQ-MPS 1350 paddle screen, which are available from Fluid-Quip, Inc. of Springfield, Ohio.

[00054] The screen for the dewatering device can include a wedge wire type with slot opening, or a round hole, thin plate screen. The round hole screen can help prevent long fine fiber from going through the screen better than the wedge wire slot opening, but the round hole capacity is lower, so more equipment may be required if using round hole screens. The size of the screen openings can range from about 45 micron to 500 micron. In another example, the screen openings can range from 100 to 300 micron. In yet another example, the screen openings can range from 200 to 250 microns. Smaller screen openings tend to increase the protein/oil/alcohol yield with higher equipment and operation cost, whereas larger screen openings tend to lower protein/oil/alcohol yield with less equipment and operation cost.

[00055] Returning now to the first liquid/solid separation step 208, the separated liquefied starch solution can be subjected to an optional oil separation step 226, which can use any type of oil separator, such as a mud centrifuge, three phase decanter, disc decanter, three phase disc centrifuge, and the like, to separate oil from the liquefied starch solution by taking advantage of density differences. In particular, the liquefied starch solution is used as heavy media liquid to float oil/emulsion/fine germ particle. The liquefied starch solution has densities of about 1.1 to 1.2 grams/cc and 0.9 to 0.92 grams/cc for oil and 1 to 1.05 grams/cc for germ.

[00056] There can be three liquid phases discharged from the oil separation step 226. The first is a light phase, which includes oil or an oil/emulsion layer. The second is a heavy liquid phase, which includes the liquefied starch solution, possibly with some small germ particles. The third phase is an underflow phase, which contains fine fiber, grit particle, and starch. The underflow phase and heavy liquid phase can be combined as is illustrated in Fig. 4A and sent to fermentation step 242, which is discussed further below.

[00057] The oil/emulsion/fine germ layer can be forwarded to an oil polish step 230 whereat the layer can be subjected to centrifugation, including a three phase decanter, three phase disc centrifuge, or the like to separate pure oil from the emulsion and fine germ particle. From the oil polish step 230, the emulsion and fine germ particle can be discharged as a heavy phase and optionally subjected to a solvent extraction step (not shown) to recover additional oil, sent to a holding tank (not shown) for additional oil recovery, or returned to join up with the combined starch solution/heavy phase from the oil separation step 226. [00058] The oil that is recovered at step 230 has a much more desirable quality in terms of color and free fatty acid content (less than 7% and, in another example, less than 5%) as compared to oil that is recovered downstream, particularly oil recovered after fermentation. In particular, the color of the pre-fermentation recovered oil is lighter in color and lower in free fatty acid content. The oil yield can reach about 47 kg/metric ton to about 55 kg/metric ton whereas current oil recovery from evaporator streams average about half that.

If the optional oil separation step 226 is not utilized here, the liquid from the first liquid/solid separation step 208 can be sent directly to fermentation step 242.

[00059] The wet cake or dewatered solids portion of the stream at the first liquid/solid separation step 208 (about 60 to 65% water) can be optionally subjected to a dewatered milling step 210, whereat the solids, particularly the germ and grit, are reduced in size via size reduction equipment. The size reduction equipment can include a hammer mill, a pin or impact mill, a grind mill, and the like. In one example, the size reduction equipment is a pin mill or grind mill. This dewatered milling step 210 is intended to break the germ and grit particles and the bonds between fiber and starch, as well as oil and protein, without cutting the fiber too fine, thereby giving sharper separation between the fiber and protein/starch/oil.

[00060] In a dewatered form, the germ and grit particles are able to break apart more easily than the fiber as a result of increased rubbing action in which less fine fiber is created, but the germ and grit are more fully milled. This results in a relatively non-uniform particle size amongst the milled solids. For example, germ and grit particles can be milled to a particle size between about 300 to 800 microns, whereas a majority of the fiber remains within a particle size range of 500 to 2000 micron. In one example, greater than 75% of the fiber remains within a particle size range of 500 to 2000 micron. In another example, no greater than 80% by weight of the total particles after the dewatered milling step 210 have a particle size less than 800 microns. In another example, no greater than 75% by weight of the total particles after the dewatered milling step 210 have a particle size less than 800 microns. In still another example, no greater than 65% by weight of the total particles after the dewatered milling step 210 have a particle size less than 800 microns. In another example, about 30% to about 50% by weight of the total particles after the dewatered milling step 210 have a particle size from about 100 microns to about 800 microns. In still another example, about 40% to about 50% by weight of the total particles after the dewatered milling step 210 have a particle size from about 100 microns to about 800 microns. In yet another example, no greater than 50% by weight of the total particles after the dewatered milling step 210 have a particle size from about 100 microns to about 800 microns. The % protein in the solid particles that are larger than 300 micron is about 29.5%. After grind and if washing techniques are utilized, the % protein in fiber can decrease from about 29.5% to about 21.1%. The % oil in fiber can decrease from about 9.6% to about 6.4%, and the % starch in fiber can decrease from about 5.5% to about 3%.

[00061] If a grind mill is used for particle size reduction at the first dewatered milling step

210, the design of the grind plates (not shown) for the grind mill can be varied to accomplish the germ and grit grinding, while tending to avoid fiber grinding. Historically, the grind plates, which are in generally opposing fashion, typically define a group of about 6 to 12 grind plate segments that form an annular ring when combined together and secured to the surface of a grind disc. Each grind plate segment and, consequently the grind plate itself, contains "tooth" designs placed in rows of annular rings or bars of various widths that extend from the inside diameter to the outside diameter of the grind plate. With bar type design grind plates, the width and depth can be varied to provide more effective grinding of the germ and grit, while tending to avoid the fiber. In one example, the bar is 20 inches (50 cm) long. Different combinations, numbers, and shapes and sizes of "teeth" or bar designs may be provided to more effectively grind the germ and grit, while tending to avoid the fiber. Also, the gap between the grind plates as well as the RPMs can be adjusted for desired performance and energy efficiency. In one example, the gap can be from 0.01 to 0.3 inch (0.25 to 7.6 mm). In another example, the plate gap is about .020 to 0.15 inch (0.51 to 3.8 mm). Also, in one example, the RPM can be from 900 to 3000 for one or more grind plates. In another example, the RPM is about 1800.

[00062] The grind plate may be composed of white iron, which has high abrasion resistance with approximately 25% chrome content to increase corrosion resistance, but can be formed of any suitable metal or alloy, plastic, composite, and the like. Also the teeth size (width, height, and length), shape of the teeth, distance between teeth, and number of teeth on each row can vary to accomplish desirable germ and grit grinding, while tending to avoid fiber grinding.

[00063] One type of grind mill having a suitable type of grind plate is the FQ-136 grind mill, which is available from Fluid-Quip, Inc. of Springfield, Ohio. This type of grind mill has one 36" inch diameter stationary disc and one 36" inch diameter rotating disc. Grind plate segments defining the grind plate are installed onto each disc, and the gap between the two discs can be varied to produce an effective grind result. Grind mills can be made with larger or smaller diameter discs. The FQ-152 grind mill also available from Fluid-Quip, Inc. of

Springfield, Ohio, has 52" inch diameter discs. Larger diameter discs can provide higher tangential velocity at the outside edge of the discs as compared to smaller discs, which can provide more impact and grinding or shear effect if run at the same rotational speeds. Grind mills can also be made with two rotating discs, which can vary in diameter. In this case, the discs rotate in opposite directions, producing a net effective disc to disc speed twice that of a single rotating disc. Increased speed will increase the number of teeth or bar crossings which will effect impact and/or shear effect on the medium passing through the grind mill.

[00064] If a pin/impact mill is used for particle size reduction, different pin sizes and types, e.g., round, triangular, hexagonal, and the like, can be used depending on operation requirements to optimize the dewatered milling step 210. In one example, the pin sizes can include round pins, which can be approximately 2 1/8 inches (2.9 cm) in height and 1 5/8 inches (4.1 cm) in diameter. Also, the RPM for the pin impact mill can be from 2000 to 3000. The pins can be made of stainless steel or other suitable corrosion resistant metal or metal alloy, plastic, composite, and the like. One suitable type of pin/impact mill, which uses an impact force to help break the germ and grit, while tending to avoid fiber grinding, is the FQ-IM40, which is available from Fluid-Quip, Inc. of Springfield, Ohio.

[00065] After milling, the solids can be sent to a first holding tank 214 whereat a liquid portion, or filtrate, which includes liquefied starch, from a third solid/liquid separation step 224, which is discussed further below, may be mixed with the solids to form a heavy slurry as part of a countercurrent wash setup in an effort to maximize alcohol, protein, and/or oil yields. An enzyme(s), such as alpha amylase, optionally can be added to the first holding tank 214 such as to assist in converting insoluble starch in the slurry to soluble starch. The heavy slurry may be held in the first holding tank 214 for a total holding time of about 2 to 4 hours at temperatures of about 60°C to 85°C so as to further solubilize starch components in the slurry stream. If the optional first dewatered milling step 210 is not present, the solids may be sent directly to the first holding tank 214.

[00066] The heavy slurry is next subjected to a second liquid/solid separation step 216 that separates a generally liquefied solution, which includes free oil, protein, starch, and fine solids (which do not need grinding), from heavy solids cake, which includes the heavier fiber, grit, and germ, which can include bound oil, protein, and/or starch. The second liquid/solid separation step 216 uses a dewatering device, e.g., a paddle screen, a vibration screen, screen decanter centrifuge or conic screen centrifuge, a pressure screen, a preconcentrator, and the like, to accomplish separation of the solids from the liquid portion.

[00067] In a continued effort to maximize alcohol, protein, and/or oil yield, the filtrate, which includes liquefied starch plus middle size solids, is removed from the slurry stream at the second liquid/solid separation step 216 and recycled back in a countercurrent fashion to mix with the ground corn flour at slurry tank 204 to create a slurry and begin liquefaction. This filtrate can replace the initial cook water typically added at the slurry tank 204. As such, cook water can be initially added to a fourth holding tank 234, as discussed further below. This counter current washing set-up allows additional liquefied starch and middle size solids to be recycled back to the first dewatered milling step 210 one or more times, without the need for additional dewatered milling equipment. The recycled liquefied starch re-visits the first liquid/solid separation step 208 whereat it can be separated out by traveling through the screen, then may be sent to optional oil separation step 226.

[00068] As with the first liquid/solid separation step 208, the second liquid/solid separation step 216 uses a dewatering device, such as a paddle screen or a preconcentrator, as above described to accomplish separation of the solids from the liquid portion. With the second liquid/solid separation step 216, the actual screen openings may be larger in size than those in the first liquid/solid separation step 208, which can provide higher alcohol and oil yield. In one example, the screen size used in the first liquid/solid separation step 208 can range from 45 micron to 300 micron, and the screen size used in the second liquid/solid separation step 216 can range from about 300 to 800 micron size. The filtrate, which is removed from the second liquid/solid separating step 216 and joined up with the ground corn flour at the slurry tank 204, contains about 6 to 10 Brix liquefied starch solution as well as solid particles (germ, grit, and protein) having sizes smaller than the screen size openings used in the second liquid/solid separation step 216. Using a smaller screen at the first liquid/solid separation step 208 and a larger screen at the second liquid/solid separation step 216, the counter-current setup allows one to target grinding of grit and germ particles greater than the screen size at the first liquid/solid separation step 208 and smaller than the screen size at the second liquid/solid separation step 216. Particles larger than the screen size at the second liquid/solid separation step 216 tend to be mostly fiber and contain less starch, so they do not need to recycle for additional milling at the first dewatered milling step 210.

[00069] The dewatered solids portion of the stream at the second liquid/solid separation step 216 may be subjected to an optional second dewatered milling step 218, whereat the solids, particularly the germ and grit, are further reduced in size via size reduction equipment. The size reduction equipment can include a hammer mill, a pin or impact mill, a grind mill, and the like. In one example, the size reduction equipment is a pin mill or grind mill. This second dewatered milling step 218 is intended to further break the germ and grit particles and the bonds between fiber and starch, as well as oil and protein, without cutting the fiber too fine, thereby giving sharper separation between the fiber and protein/starch/oil. In a dewatered form, the germ and grit particles are able to break apart more easily than the fiber as a result of increased rubbing action in which less fine fiber is created, but the germ and grit are more fully milled. This results in a relatively non-uniform particle size amongst the milled solids. For example, germ and grit particles can be milled here to particle sizes between about 75 to 150 microns, whereas a majority of the fiber remains within a particle size range of 300 to 800 micron. In one example, greater than 75% of the fiber remains within a particle size range of 300 to 1000 micron. In another example, about 30% to about 60% by weight of the total particles after the second dewatered milling step 218 have a particle size from about 100 microns to about 800 microns. In still another example, about 40% to about 50% by weight of the total particles after the second dewatered milling step 218 have a particle size from about 100 microns to about 800 microns. In yet another example, no greater than 60% by weight of the total particles after the second dewatered milling step 218 have a particle size from about 100 microns to about 800 microns. In yet another example, no greater than 50% by weight of the total particles after the second dewatered milling step 218 have a particle size from about 100 microns to about 800 microns.

[00070] After milling, the solids can be sent to the second holding tank 220 whereat a liquid countercurrent stream from an optional fourth solid/liquid separation step 232, or from a fiber recovery step 240 if the fourth solid/liquid separation step 232 is not present, may be mixed therewith to form a corn slurry. The slurry may be held in the second holding tank 220 for a total holding time of about 2 to 4 hours at temperatures of about 60°C to 85°C so as to further solubilize starch components in the slurry stream.

[00071] Various enzymes (and types thereof) such as amylase or glucoamylase, fungal, cellulase, cellobiose, protease, and the like can be optionally added during and/or after the dewatered milling steps 210, 218 or the holding tanks 214, 220 to enhance the separation of components, such as to help break the bonds between protein, starch, and fiber.

[00072] From the second holding tank 220, the corn slurry stream is next subjected to the third liquid/solid separation step 224 that uses a dewatering device, e.g., a paddle screen, a vibration screen, a filtration, scroll screen, or conic screen centrifuge, a pressure screen, a pre- concentrator, and the like, to accomplish separation of the solids from the liquid portion. In one example, the dewatenng device is a paddle screen or a pre-concentrator, as above described. With the second liquid/solid separation step 216, the actual screen openings may be larger in size than those in the first and/or third liquid/solid separation steps 208, 224. At the third liquid/solid separation step 224, the liquefied solution (about 70-85% by volume), which includes oil, protein, starch, and fine solids, is separated from the heavy solids cake (about 15-30% by volume), which includes the heavier fiber, grit, and germ. The heavy solids cake is sent to third holding tank 225 whereat a liquid countercurrent stream from the fiber recovery step 240 is combined therewith to form a slurry.

[00073] The various solid/liquid separation steps 208, 216, 224, dewatered milling steps

210, 218, and holding tanks 214, 220, 225 represent a front end milling method, which optionally utilizes a counter current wash setup. While multiple solid/liquid separation steps, dewatered milling steps, and holding tanks are shown here and utilized, it should be understood that less than or more than as described may be utilized, including none at all. One preferred milling method is a Selective Grind Technology system offered by Fluid Quip Process Technologies of Springfield, Ohio that utilizes paddle dewatering screens and disc mills, for example, and which is disclosed in U.S. Patent Application No. 13/428,263 entitled "Dry Grind Ethanol Production Process And System With Front End Milling Method", filed March 23, 2012, the contents of which is expressly incorporated by reference herein in its entirety. In one example, the system and process for alcohol production 200, similar to Figs. 3 and 3A, can include the slurry stream from the liquefaction step 206 being sent directly to fiber recovery step 240 and processed from there, as is further discussed below. Here, the liquid from the fiber recovery step 240 may be recycled back to the slurry tank 204, which can also have cook water added directly thereto. [00074] With respect to the counter current wash setup, in one example, it should be understood that cook water may be provided directly to the holding tank 214, 220, 225, 234 or the slurry tank 204 that corresponds to the one situated just before fiber recovery step 240. Then, the liquid portion from the fiber recovery step 240 and solid/liquid separation steps 208, 216, 224, 232 can be recycled back to the corresponding holding tank 214, 220, 225, 234 or the slurry tank 204 that is situated two back therefrom, with the exception that the first separated liquid portion, for example, the liquid portion from the first solid/liquid separation step 208, is to be sent to fermentation or optionally oil separation step 224.

[00075] With continuing reference to Fig. 4A, from the third holding tank 225, the corn slurry stream is sent and subjected to an optional fourth solid/liquid separation step 232 that uses a dewatering device, e.g., a paddle screen, a vibration screen, a filtration, scroll screen, or conic screen centrifuge, a pressure screen, a pre-concentrator, and the like, to accomplish separation of the solids, including fiber, from the liquid portion, which includes starches/sugars. In one example, the dewatering device is a paddle screen or a pre-concentrator, as above described. One or more additional solid/liquid separation steps may be further included in the front end of the corn dry grind ethanol system and process 102 system such as reduce the amount of cook or wash water required. In one example, the corn dry grind ethanol system and 102 can include from 5-7 total solid/liquid separation steps. The dewatered solids portion of the stream is sent to an optional fourth holding tank 234 whereat cook water may be mixed therewith to form a heavy slurry.

[00076] If the optional fourth solid/liquid separation step 232 and holding tank 234 are not present, the corn slurry stream from the third holding tank 225 can be sent directly to fiber recovery step 240 and the liquid from the fiber recovery step 240 can be sent back to the second holding tank 220 in a countercurrent fashion. In addition, cook water can be mixed with the dewatered solids portion at the third holding tank 225.

[00077] The heavy slurry from the fourth holding tank 234 may be subjected to fiber recovery step 240, which helps to separate out clean fiber, e.g., white fiber. The amount of wash water in the front end of the corn dry grind ethanol system and process 102 can vary depending on the amount of starch, protein and oil desired in the final fiber product. In particular, a dewatering device, e.g., a paddle screen, vibration screen, filtration centrifuge, pressure screen, screen bowl decanter and the like, can be used at the fiber recovery step 240 to accomplish separation of the fiber from a liquid portion. One exemplary dewatering device for the fiber recovery step 240 is shown and described in Lee U.S. Patent Application Publication No.

2010/0012596, the contents of which are incorporated herein by reference in its entirety.

Counter current washing is set-up here so that the liquid portion that is separated out can be sent back to the third holding tank 225. This counter current washing set-up allows additional liquefied starch, for example, to be recycled back to the corn slurry stream so that it may be later subjected to fermentation.

[00078] The separated fiber or fiber stream, which includes from about 30-50% solids, optionally can be sent to a dryer and dried to about 10% moisture for use as animal feed stock or secondary alcohol feed stock, for example. The separated fiber may also be optionally used as a supplemental fuel source, i.e., energy production. In one example, the separated fiber may be sent to and burned in furnaces in the combination corn and sugar cane processing plant, which can be used to boil water and generate high pressure steam.

[00079] One preferred method of recovery of corn fiber and corn germ/oil prior to fermentation is disclosed in U.S. Patent Application No. 13/377,353 entitled "A System And Method For Separating High Value By-Products From Grains Used For Alcohol Production", filed December 9, 201 1, the contents of which is expressly incorporated by reference herein in its entirety.

[00080] The liquid portion or corn slurry stream from the optional oil separation step 224 or the first solid/liquid separation step 208 defines a liquefied starch/sugar solution. The liquefied starch sugar solution may be sent directly to fermentation at fermentation step 242. The liquefied starch/sugar solution at fermentation step 242, which excludes fiber and optionally oil, can be subjected to fermentation to convert the sugars to alcohol.

[00081] With further reference to Fig. 4 A, the system and process for alcohol production

200 generally depicts a front end of the refined sugar/alcohol production system and process 202, which again may be modeled after the front end of the system and process 10 as shown in Fig. 1 , in which sugar cane can be processed to produce alcohol or sugar and alcohol, such as ethanol. As described above, in the front end refined sugar/alcohol production system and process 202, sugar cane juice and/or the molasses byproduct can be sent to a fermentation step 244, as shown in Fig. 4A and which is understood to be a part of the front end of the refined sugar/alcohol production system and process 202. The fermentation step 244 converts the sugars therein to alcohol.

[00082] With fiber separated from the corn slurry stream and after fermentation steps 242,

244, respectively, each of the fermented sugar cane and corn slurry streams can be combined for alcohol recovery at distillation step 250, as is shown in Fig. 4B, which is a continuation of the flow diagram of Fig. 4A and illustrates the back end of the system and process for processing alcohol 200 simultaneously from sugar cane and corn. In particular and with continuing reference to Figs. 4A and 4B, beer from the corn fermentors at fermentation step 242 can be sent to distillation feed tanks or units at distillation step 250 to be combined with the wine from the sugar cane fermentors at fermentation step 244. The mixed stream of sugar cane wine and corn beer can then be sent to distillation where the ethanol portion can be distilled from the mixed beer feed stream. This setup also allows for the optional recovery of yeast from the fermented corn slurry stream and/or the fermented sugar cane slurry stream prior to distillation, and which can be recycled for re-use at fermentation steps 242, 244, if desired.

[00083] In another embodiment, each of the fermented sugar cane and corn slurry streams can remain separate and further sent to separate distillation units for alcohol recovery at distillation step 250. In particular, beer from the corn fermentors at fermentation step 242 and wine from the sugar cane fermentors at fermentation step 244 can be sent to separate distillation feed tanks or units at distillation step 250, with the resulting corn and sugar cane stillage being combined after distillation for further processing, as desired and as described herein. In yet another embodiment, beer from the corn fermentors at fermentation step 242 and wine from the sugar cane fermentors at fermentation step 244 can be sent to separate beer columns of the distillation feed tanks or units at distillation step 250. The resulting corn and sugar cane stillage can be combined thereafter for further processing, as desired and as described herein, and the overhead from the beer columns can be combined for further rectification for alcohol recovery. In other words, the streams are kept separate for only part of the distillation step 250.

[00084] If optional recovery of yeast from the fermented corn slurry stream and/or the fermented sugar cane slurry stream prior to distillation is not necessarily desired, the corn slurry stream, with its fiber and oil optionally removed therefrom, and the sugar cane slurry stream can be combined for fermentation of the sugars at fermentation step 242, for example, for alcohol production, subsequently followed by distillation step 250 for recovery of the alcohol. In other words, the two streams would not need to be separately fermented in different fermentors.

[00085] With continuing reference to Fig. 4B, at the distillation step 250, the fermented solution is separated from non-fermentables called stillage, which can include fine fiber, protein, and additional oil, for example, to produce the alcohol. The alcohol yield is about 2.78 gal/bu (413 1/metric ton), which is an increase of about 1% over conventional yields.

[00086] After distillation, the back end of the system and process 200 can include a protein separation step 252, which uses, for example, a decanter, a nozzle centrifuge, or a disc decanter to recover protein (corn gluten as well as spent yeast and fine germ, including sugar cane yeast protein that is currently disposed of through the vinasse channel) from the stillage. The recovered protein and yeast can be subjected to a protein dewatering step 254, which uses a dewatering device, e.g., a paddle screen, a vibration screen, screen decanter centrifuge, decanter centrifuge, or conic screen centrifuge, a pressure screen, a preconcentrator, and the like, to accomplish separation of the protein from a liquid portion. The liquid portion can be used as backset, which can be sent up to the slurry tank 204 on the front end. The dewatered protein includes about to 20% to 35% DS and can be sent to a drying step 256, which utilizes a dryer, such as a rotary, ring dryer, spray dryer, or adiabatic dryer to yield a gluten/germ mix (protein meal), which has about 42% to 70% protein and about 4-10% moisture. The total protein yield from the process is from about 3.25 lb/bu to about 6 lb/bu (about 128 kg/metric ton to about 236 kg/metric ton).

[00087] In another embodiment, protein separation (and recovery) can be implemented on the front end prior to fermentation in a similar manner as just explained and depicted in Fig. 4B. In this embodiment, protein separation (and recovery) generally may occur between liquefaction step 208 and fermentation step 242. In one example, the liquid streams from a front end protein separation step and protein dewatering step, which would be analogous to the thin stillage and backset streams in Fig. 4B coming from protein separation step 252 and protein dewatering step 254, respectively, can be sent directly to fermentation. With protein and fiber separated from the corn slurry stream, the corn slurry stream and the sugar cane slurry stream, as shown in Fig. 4A, can be directly combined for fermentation of the sugars at fermentation step 242 for alcohol production, subsequently followed by distillation step 250 for recovery of the alcohol. The separation of protein from the corn slurry stream prior to fermentation also can permit recovery (and subsequent recycling) of yeast from the combined fermented corn slurry stream and the fermented sugar cane slurry stream, if so desired.

[00088] The leftover stillage or "thin" stillage from the protein separation step 252 may be sent to an optional back end oil separation step 260, which can use any type of oil separator, such as a mud centrifuge, three phase decanter, disc decanter, three phase disc centrifuge, and the like, to separate oil from the thin stillage by taking advantage of density differences. There can be three phases discharged from the oil separation step 260. The first is a light phase, which includes oil or an oil/emulsion layer. The second and third phases, which can be combined as is illustrated in Fig 4B, include heavier phases, such as small germ particles, fine fiber, grit particle, and starch.

[00089] The oil/emulsion layer can be forwarded to an oil polish step 262 whereat the layer can be subjected to centrifugation, including a three phase decanter, three phase disc centrifuge, or the like to separate pure oil from the emulsion and fine germ particle, for example. From the oil polish step 262, the emulsion and fine germ particle can be discharged as a heavy phase and optionally subjected to a solvent extraction step (not shown) to recover additional oil, or returned to join up with the de-oiled underflow heavier phases from the oil separation step 260 at sixth holding tank 264. From here, the mixture can be further treated, such as further dried and utilized as fertilizer or used as a supplemental fuel source at the combination corn and sugar cane processing plant. The oil can be sold as a separate high value product.

[00090] If the optional back end oil separation step 260 is not utilized here, the thin stillage from the protein separation step 252 can be treated like the thin stillage in a typical corn dry grind ethanol production system and process 0 as is shown in Fig. 2. In particular, the stillage from the protein separation step 252 can be sent to evaporators in an evaporation step to boil away moisture, leaving a thick syrup that contains the soluble (dissolved) solids from fermentation. That concentrated slurry itself, which includes oil, may be subjected to an optional oil recovery, such as oil separation step 260, whereat the slurry can be treated as discussed above to separate oil from the syrup. The separated oil/emulsion layer can be forwarded to oil polish step 262 and the syrup portion can be further treated, such as further dried and utilized as fertilizer or mixed with the wet cake and sold as DWGS or DDGS, for example.

[00091] In yet another example, the liquid that is recovered from protein dewatering step

254, may itself be subjected to a back end oil separation, such as oil separation step 260 followed by an oil polish step, and the thin stillage from the protein separation step 252 can instead be used as backset, which can be sent up to the slurry tank 204 on the front end. Alternatively, the liquid that is recovered from the protein separation step 252 can be treated like the thin stillage in a typical corn dry grind ethanol production system and process 50 as is shown in Fig. 2. In particular, the stillage from the protein separation step 252 can be sent to evaporators in an evaporation step to boil away moisture, leaving a thick syrup that contains the soluble

(dissolved) solids from fermentation. That concentrated slurry, which includes oil, may be subjected to an optional oil recovery, such as oil separation step 260, whereat the slurry can be treated as discussed above to separate oil from the syrup. The separated oil/emulsion layer can be forwarded to an oil polish step and the syrup portion can be further treated, such as further dried and utilized as fertilizer or mixed with the wet cake and sold as DWGS or DDGS, for example. With reference now to Figs. 5A and 5B, a system and process 200A is shown for processing alcohol simultaneously from sugar cane and corn in accordance with another embodiment of the invention. Fig. 5A, which shows a front end of the system and process for processing alcohol 200A simultaneously from sugar cane and corn, is identical to Fig. 4A. Fig. 5B, which is a continuation of the flow diagram of Fig. 5 A and shows the back end of the system and process for processing alcohol 200A simultaneously from sugar cane and corn, discloses a variation on protein separation and recovery, which occurs after fermentation but prior to distillation, as further described next.

[00092] In Figs. 5A and 5B, with fiber separated from the corn slurry stream and after fermentation steps 242, 244, respectively, each of the fermented sugar cane and corn slurry streams can be combined for protein (and yeast) separation and recovery at protein separation step 280, which is situated prior to distillation step 250. In particular, beer from the corn fermentors can be combined with the wine from the sugar cane fermentors and the mixed stream of sugar cane wine and corn beer can be sent to the protein separation step 280. Alternatively, the corn slurry stream, with its fiber and oil optionally removed therefrom, and the sugar cane slurry stream can be combined for fermentation of the sugars at fermentation step 242, for example, for alcohol production, subsequently followed by the protein separation step 280. In other words, the two streams do not need to be separately fermented in different fermentors. The protein separation step 280 decreases the risks of fouling of the process during the distillation step 250, which may occur otherwise, and helps prevent denaturing of the protein, which can occur during distillation.

[00093] The protein separation step 280, which uses, for example, a disc/stack centrifuge, a nozzle centrifuge, disc decanter, or a decanter to recover protein (corn gluten) as well as spent yeast, including sugar cane yeast protein that is currently discharged through the vinasse channel) from the combined fermented corn and sugar cane slurry streams. The overflow stream from the protein separation step 280, which includes alcohol, solubles, and a low percentage of insolubles, is sent forward to the distillation step 250.

[00094] The separated protein (and yeast) is first subjected to an alcohol stripping step

282, which uses, for example, a stripping column to recover any residual alcohol from the protein/yeast stream. The residual alcohol is sent to the distillation step 250 and the stripped protein/yeast stream is sent to a protein/yeast dewatering step 284, which uses a dewatering device, e.g., a paddle screen, a vibration screen, screen decanter centrifuge or conic screen centrifuge, a pressure screen, a preconcentrator, a decanter, and the like, to accomplish separation of the protein and yeast from a liquid portion. In one example, a sludge style decanter, such as the Alfa Laval 944 or SG2-600 decanter setup available from Alfa Laval of Richmond, Virginia, can be used to dewater the protein/yeast stream. The liquid portion can be used as backset, which can be sent up to the slurry tank 204 on the front end. The dewatered protein and yeast can be sent to a drying step 286, which utilizes a dryer, such as a rotary, ring dryer, spray dryer, or adiabatic dryer to yield a gluten/yeast mix.

[00095] With continuing reference to Fig. 5B, at distillation step 250, alcohol is recovered.

In particular, at the distillation step 250, the fermented solution is separated from non- fermentables called stillage, which can include fine fiber and additional oil, to produce the alcohol. After distillation, the back end of the system and process 200A can include optional back end oil separation step 260, which can use any type of oil separator, such as a mud centrifuge, three phase decanter, disc decanter, three phase disc centrifuge, and the like, to separate oil from the stillage by taking advantage of density differences. There can be three phases discharged from the oil separation step 260. The first is a light phase, which includes oil or an oil/emulsion layer. The second and third phases, which can be combined as is illustrated in Fig 5B, include heavier phases, such as small germ particles, fine fiber, grit particle, and starch.

[00096] The oil/emulsion layer can be forwarded to an oil polish step 262 whereat the layer can be subjected to centrifugation, including a three phase decanter, three phase disc centrifuge, or the like to separate pure oil from the emulsion and fine germ particle, for example. From the oil polish step 262, the emulsion and fine germ particle can be discharged as a heavy phase and optionally subjected to a solvent extraction step (not shown) to recover additional oil, sent to a holding tank (not shown) for additional oil recovery, or returned to join up with the de- oiled underflow heavier phases from the oil separation step 260 at sixth holding tank 264. From here, the mixture can be further treated, such as further dried and utilized as fertilizer or used as a supplemental fuel source at the combination corn and sugar cane processing plant.

[00097] If the optional back end oil recovery step 260 is not utilized here, the stillage from the distillation step 250 can be treated like the thin stillage in the typical corn dry grind ethanol production system and process 50 as shown in Fig. 2. In particular, the stillage can be sent to evaporators in an evaporation step to boil away moisture, leaving a thick syrup that contains the soluble (dissolved) solids from fermentation. That concentrated slurry, which includes oil, may be subjected to an optional oil recovery, such as oil separation step 260, whereat the slurry can be treated as discussed above to separate oil from the syrup. The separated oil/emulsion layer can be forwarded to oil polish step 262 and the syrup portion can be further treated, such as further dried and utilized as fertilizer or mixed with the wet cake and sold as DWGS or DDGS, for example.

[00098] In yet another example, the liquid that is recovered from protein dewatering step

284, may itself be subjected to a back end oil separation, such as oil separation step 260 followed by an oil polish step, and the thin stillage from the distillation step 250 can instead be used as backset, which can be sent up to the slurry tank 204 on the front end.

[00099] 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 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, in part, on corn, virtually any type of grain, including, but not limited to, wheat, barley, sorghum, rye, rice, oats and the like, can be used. Also, while the focus herein has been on ethanol production, it should be understood that alcohol production can include, for example, methanol, ethanol, butanol, and the like, as well as modifications and derivatives thereof. It should also be understood that the corn slurry stream and corn sugar cane streams can be combined after fiber separation but just before or at fermentation or after fiber separation but just before or at distillation, for example. In addition, it should also be understood that the processing of the corn and sugar cane may be performed independent of one another such that one of them can be still be processed, as discussed above, when the other is not. Also, the output of each processed corn and sugar cane may be adjusted depending upon the supply and demand of the raw materials themselves and/or the resulting alcohol and/or byproducts. Additional advantages and modifications will readily appear to those skilled in the art. 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.

[000100] What is claimed is:

Claims

1. A process for producing alcohol from sugar cane and corn, comprising: separately milling corn kernels into corn flour and sugar cane to extract sugar cane juice; separately mixing the corn flour and the extracted sugar cane juice with a liquid to produce separate corn and sugar cane slurry streams, the corn slurry stream including free oil, germ, protein, starch, and fiber and the sugar cane slurry stream including sugar; prior to fermentation, converting the starch to sugar and separating the fiber from the corn slurry stream; and thereafter either separately fermenting sugars from the corn slurry stream and the sugar cane slurry stream to produce alcohol, and combining and distilling the fermented sugars to recover the alcohol; or combining the sugars from the corn slurry stream and the sugar cane slurry stream and fermenting the sugars together to produce alcohol, and distilling the fermented sugars to recover the alcohol.

2. The process of claim 1 comprising the steps of separately fermenting the sugars from the corn slurry stream and the sugar cane slurry stream to produce alcohol, and combining and distilling the fermented sugars to recover the alcohol.

3. The process of claim 2 further comprising recovering yeast, which is used in fermenting the sugars, from the fermentation step.

4. The process of claim 1 comprising the steps of combining the sugars from the corn slurry stream and the sugar cane slurry stream and fermenting the sugars together to produce alcohol, and distilling the fermented sugars to recover the alcohol.

5. The process of claim 1 further comprising, prior to fermentation, separating and recovering the free oil from the corn slurry stream.

6. The process of claim 1 further comprising producing a stillage byproduct, including additional free oil, from the distillation step, and, after distillation but prior to any back end evaporation of the stillage, separating the additional free oil from the stillage and returning the additional free oil to the process prior to fermentation whereat the additional free oil is recovered with the free oil.

7. The process of claim 1 wherein the sugars from the sugar cane slurry stream for alcohol production come from molasses as a byproduct of refined sugar production.

8. The process of claim 1 further comprising producing a stillage byproduct, including protein, from the distillation step, and, after distillation, separating and recovering the protein from the stillage.

9. The process of claim 1 further comprising producing a stillage byproduct, including additional free oil, from the distillation step, and, after distillation, separating and recovering the additional free oil from the stillage.

10. The process of claim 1 further comprising, after fermentation but prior to distillation, separating and recovering the protein from the corn slurry stream.

11. The process of claim 1 further comprising, prior to fermentation, producing refined sugar from at least a portion of the sugar from the sugar cane slurry stream.

12. The process of claim 1 wherein the liquid for mixing with the corn flour is part of a countercurrent wash setup.

13. The process of claim 1 further comprising, prior to fermentation, separating and recovering the protein from the corn slurry stream.

14. A method for converting a sugar cane processing plant into a combination sugar cane and corn processing plant for alcohol production, comprising: incorporating into an existing sugar cane processing plant a separate front end corn alcohol production process, which includes a milling device, a liquefaction system, and a front end dewatering device that separates fiber from a corn slurry stream prior to fermentation of the corn slurry stream; and combining together, no later than distillation but after fiber separation of fiber from the corn slurry stream, separate corn slurry and sugar cane slurry streams including sugars for alcohol production and recovery.

15. The method of claim 14 wherein the front end corn alcohol production process is a front end dry corn dry grind alcohol production process.

16. The method of claim 14 wherein combining together comprises combing together, before fermentation but after fiber separation of fiber from the corn slurry stream, separate corn slurry and sugar cane slurry streams for alcohol production and recovery.

17. A system for producing ethanol from sugar cane and corn comprising: a first milling device that mills corn kernels into corn flour, and a second milling device that separately mills sugar cane to extract sugar cane juice; a first slurry tank in which the corn flour mixes with a liquid to produce a corn slurry stream including free oil, germ, protein, starch, and fiber, and a second slurry tank in which the sugar cane juice mixes with a liquid to produce a sugar cane slurry stream including sugar; at least one holding tank, which aids in converting the starch to sugar; a dewatering device, which separates the fiber from the corn slurry stream prior to fermentation; and either a first fermentor in which sugars from the corn slurry stream are fermented, and a second fermentor in which sugars from the sugar cane slurry stream are separately fermented to produce alcohol, and at least one distillation device whereat the alcohol is recovered from combined fermented corn slurry and sugar cane streams; or at least one fermentor whereat sugars from the corn slurry stream and the sugar cane slurry stream are fermented together, and a distillation device whereat the alcohol is recovered from the fermented sugars.

18. The system of claim 17 comprising the first fermentor in which sugars in the corn slurry stream are fermented, and the second fermentor in which sugars from the sugar cane slurry stream are separately fermented to produce alcohol, and the at least one distillation device whereat the alcohol is recovered from combined fermented corn slurry and sugar cane streams.

19. The system of claim 17 comprising the at least one fermentor whereat sugars from the corn slurry stream and the sugar cane slurry stream are fermented together, and the distillation device whereat the alcohol is recovered from the fermented sugars.

20. The system of claim 17 further comprising an oil separation device, which separates the free oil from the corn slurry stream prior to fermentation.

21. The system of claim 17 further comprising a protein separation device, which separates and recovers the protein after distillation or after fermentation but prior to distillation.

22. The system of claim 17 further comprising a sugar production device that produces refined sugar from at least a portion of the sugars from the sugar cane slurry stream.

23. The system of claim 22 wherein the sugars from the sugar cane slurry stream for alcohol production come from molasses as a byproduct of refined sugar production.