DE102007033988A1 - Producing purified starch comprises grinding cereals containing starch in an air vortex mill to starch flour, separating bran from the flour and subsequently separating proteins from the flour - Google Patents

Abstract

Producing purified starch comprises grinding cereals containing starch in an air vortex mill to starch flour, so that 90% of the flour particles possess a particle size of 150-250 mu m, separating bran from the flour and subsequently separating proteins from the flour. Independent claims are included for: (1) a purified starch obtained by the above method; (2) producing ethanol comprising fermenting the purified starch by microorganisms to a fermentation broth, optionally after the liquefaction of the starch, producing a mash by separating microorganisms from the fermentation broth and separating ethanol from the mash; (3) producing a first sugar solution comprising preparing or providing starch milk, thermal liquefying the starch of the starch milk, cleaving the starch to obtain mono, di- and/or oligosaccharides, separating fats, oils and proteins from the starch milk, and recovering the first sugar solution as permeate of a first membrane filtration of the starch milk; (4) producing a second sugar solution comprising preparing or providing pentosan fractions of starch milk, optionally concentrating the pentosan fractions, cleaving cellulose and/or hemi-cellulose of the pentosan fractions, preferably under acid additives, separating fats, oils and proteins from the pentosan fractions, recovering the second sugar solution as permeate of a third membrane filtration of the pentosan fraction; (5) a sugar solution obtained by the above method; (6) a fermentation procedure for producing ethanol, comprising providing the first or second sugar solution, carrying out the fermentation to produce a fermentation broth, separating microorganisms from the fermentation broth to produce a mash, purifying the mash by membrane filtration to a permeate; and (7) a distillation method comprising carrying out a distillation for producing a distillation product vapor, condensing a first distillation product vapor partial stream in a vapor compressor, operating a heat exchanger with the compressed partial stream to obtain heat for operating the distillation and to obtain a condensate as return flow for the distillation, and/or purifying a second distillation product vapor partial stream in a permeation- or pervaporation layer to obtain a purified distillation product and a depleted distillation product vapor partial stream, where the depleted distillation product vapor partial stream is condensed in a vapor compressor and used in a heat exchanger to obtain heat for operating the distillation and to obtain a condensate as return flow for the distillation.

Description

The The invention relates to a process for the production of ethanol, gluten, Bran, yeast and carbon dioxide from cereals. In particular, it concerns the invention improved processes for the production of ethanol, Gluten, bran, yeast and carbon dioxide from cereals.

The Fermentation (fermentation) for the preparation of alcohols from the raw material grain is one of the oldest biotechnological Method and is u. a. for the production of alcoholic Beverages, such as beer and wine, used. Industrially used alcohol can be represented by the fermentation of cereals. Appropriate Alcohols, especially ethanol, are used as starting material for the manufacture of pharmaceutical products and formulations, cosmetic Products and used to synthesize a range of chemicals.

Ethanol has long been known as an energy carrier, but was not economically viable in the past due to the higher process costs compared to the extraction of fossil fuels. Due to the shortage of fossil oil reserves and the reduction in CO ₂ demanded by the Kyoto agreement, the potential use of bioethanol as an energy source has gained new importance. Economic as well as ecological interests demand an improvement of the existing processes for the production of ethanol as well as an efficient use of the existing biomass on a large scale.

was standing There are many methods of making alcohols in the art from biomass. Because completely different starting material (Glucose, starch or cellulose) for these procedures can be used, u. a. Sugar cane, sugar beet, cereals, etc. also differ the methods for the production of the bioalcohol strong of each other. Also when using identical starting materials There are different technological and biological process concepts.

• (a) zunächst das Getreide vermahlen,
• (b) das gemahlene Getreide in Wasser suspendiert und mit Mikroorganismen, insbesondere Hefen, versetzt,
• (c) die so erhaltene Fermenterbrühe wird fermentiert, und anschließend wird
• (d) Ethanol durch thermische Trennung aus der Fermenterbrühe aufkonzentriert.

In conventional processes for the production of ethanol from cereals by fermentation is usually:

• (a) first grind the grain,
• (b) suspending the ground grain in water and adding microorganisms, in particular yeasts,
• (c) the fermenter broth thus obtained is fermented, and then
• (d) ethanol is concentrated by thermal separation from the fermenter broth.

The Separation of the ethanol is usually carried out by distillation. In this case, the residue residue is stillage, which is usually concentrated and as a fertilizer or after drying as a proteinaceous Feed is used.

Examples of corresponding fermentation processes and for individual process steps are AT 398981 . DE 29 44 483 C2 . DE 30 07 138 C2 and US Pat. No. 6569653 B1

The in the usual process resulting vinasse is very containing protein, which is generally processed into feed and used is, can be used only conditionally as a fertilizer. The Production of the feed, in particular the drying of the stillage However, it requires a lot of energy, which is about 50% of the energy which covers the entire manufacturing process of a standard plant needed for bioethanol.

CO ₂ is a climate-damaging gas whose release should be avoided, economic use would make sense. The Greenhouse Gas Emissions Trading Act of 8 July 2004 makes the avoidance and reduction of CO ₂ economically sensible.

The resulting in a fermentation CO ₂ is generally released to the environment after the gases have been cleaned and separated from environmentally problematic impurities. The use of enriched with CO ₂ air zb by horticultural operations, has been possible only conditionally.

The overall method of the prior art requires very large amounts of water, in particular for the mashing per tonne of grain used up to 3.5 m ^{3 of} fresh water needed, this water must be worked up in part cost and energy intensive.

In all conventional methods according to the prior art, the problem arises that the energy consumption is very high, that the costs for enzymes and auxiliaries are very high, that short cleaning intervals are required for the plant, that the fermenter broth is fermented, and Obtaining the ethanol a long residence time is required, which means that the system is a total of equipment very expensive, since very large amounts of liquids and solids must be moved. System sizes for daily capacity of more than 100 m ³ / ethanol can therefore be realized only with considerable effort. It was therefore the object of the invention to remedy the disadvantages described above or to reduce them. In particular, it was the object of the invention to reduce the energy and water requirements of an ethanol production, without significantly affecting the ethanol yield or the duration of the process.

• i) Mahlen von stärkehaltigem Getreide in einer Luftwirbelmühle zu einem Stärkemehl, so dass 90% der Partikel des Mehls eine Partikelgröße von 150–250 μm, vorzugsweise 180–220 μm und besonders bevorzugt von 190–210 μm besitzen,
• ii) Abtrennen von Kleie vom Mehl, und anschließend
• iii) Abtrennen von Proteinen vom Mehl.

According to the invention, it has now been found that the method of ethanol production can be carried out on the whole energy-time and cost-saving, when a certain-purified starch is used as fermentation educt. Accordingly, according to the invention, there is provided a process for preparing purified starch comprising the steps of:

• i) grinding starchy cereal in a fluidized air mill into a cornstarch such that 90% of the particles of the flour have a particle size of 150-250 μm, preferably 180-220 μm and particularly preferably 190-210 μm,
• ii) separating bran from the flour, and then
• iii) separating proteins from the flour.

there is the milling of the crop in an air vortex mill of special meaning. Surprisingly, it has turned out that for the energy-saving implementation of a Fermentation process the gentle grinding of cereal especially is beneficial. If the fine structure of the starch particles of the ground cereal close to that of the unground cereal comes, can be a particularly good fermentation and separation of the Ethanols of the fermenter broth or mash can be achieved. Best results for a gentle grinding were with achieved an air vortex mill.

When Cereals in the context of this invention are in particular wheat, maize or Tritikale used. The use of wheat is particularly preferred. The bran is preferably separated with a sieve. To the Separating the proteins preferably makes the ground starch mashed with water and the proteins separated by sieving and optionally dried. The separated proteins are preferably processed into gluten.

• iv) Bereitstellen gereinigter Stärke,
• v) Fermentieren der in Schritt iv) bereitgestellten Stärke durch Mikroorganismen zu einer Fermenterbrühe, gegebenenfalls nach Verflüssigen der Stärke,
• vi) Herstellen einer Maische durch Abtrennen von Mikroorganismen aus der Fermenterbrühe,
• vii) Abtrennen von Ethanol aus der Maische.

According to the invention, an actual process for the production of ethanol is further specified which uses the starch which can be prepared by the above-described purification process. The method comprises the steps:

• iv) providing purified starch,
• v) fermenting the starch provided by step iv) by microorganisms to a fermenter broth, optionally after liquefying the starch,
• vi) producing a mash by separating microorganisms from the fermenter broth,
• vii) separating ethanol from the mash.

By the inventive method could be surprising Advantages can be achieved: By using air vortex mills, the natural fine structure of the starch, the Protein and the bran obtained can be particle sizes be achieved by 200 microns. The retention of the natural structure the starch, the bran as well as the proteins allows it Separation of bran and proteins from starch carried out an enzymatic or thermal treatment of the substrate must become. This results in particular advantages in the fermentation; considerably shorter fermentation times were achieved here, conventional processes require fermentation times of 60 hours for a fermentation cycle, through the The process according to the invention became a fermentation time reached of less than 40 hours, thereby the apparatus required be significantly restricted. It could be the use of Enzymes are reduced, the cost of water treatment was lowered, fresh water is not needed, sewage have no significant burden and can be passed on to consumers be given. According to the invention could continue surprising be achieved by separating all by-products the thermal treatment no longer produces any sludge, whereby substantial advantages are achieved in the distillation. The aqueous residue of the distillation and rectification contains as main ingredient organic compounds that can be used thermally or otherwise.

advantages result in a distillation to separate the ethanol in the Essentially through energy and time savings as well as a considerable saving in the processing of by-products (bran, proteins, yeast).

The inventive method, in particular when the actual process of ethanol production is combined with the method for producing purified starch thus advantageously producing ethanol, gluten, bran, Yeast and carbon dioxide from grain.

The By-products of protein, bran and those from the solid phase of the vinasse Yeast obtained can be used as feed and of high quality, as feed the methods known in the art be prepared because the by-products due to a low thermal load were exposed.

Preferably The grain is first passed through before shredding Addition of liquid, preferably water, a swelling subjected. The grain is then ground in a swollen state, since the bran can be separated well in this state, the bran is separated by sieves.

Air vortex mills cause the material to be ground into extreme turbulence and, as a result of the impact of particles on particles, as well as by impact with the tool, the material to be ground is comminuted by impulse transmission. The regrind is made by Luftwir The rotation of the air is induced by the high radial acceleration and the high path speed of the rotating tool. A high volume of air efficiently removes the crushed grain and allows a low thermal load on the grain.

The Milling the grain with air vortex mills allows the separation of the proteins before liquefaction, saccharification initiated by enzymes, the proteins are transmitted through Decanting is separated and dried, creating a starch milk and gluten.

The Carbohydrates contained in the starch milk are used in conventional Enzymatically liquefied, saccharified and then fermented.

equivalent Amounts of ethanol to the starch used during the fermentation, by the yeasts, which is generally used to start the Fermentation can be added, formed. The fermentation can after one of the methods known in the art become. The fermentation comes to a halt when all fermentable carbohydrates are fermented. After completion of the fermentation, the microorganisms become and especially the yeast separated and worked up to forage yeast.

The CO ₂ produced in the fermentation comes from renewable raw materials and has only slight contamination with other gases compared to conventionally generated CO ₂ . It can be collected from the fermenter exhaust air, separated in a conventional manner and condensed.

By the fermentation and subsequent separation of the yeast a mash is received. The alcohol in the mash is preferably distilled and rectified, can thereby the known methods for distillation and rectification used become. The drainage of the separated ethanol takes place preferably by diaphragm sieves. By the invention Separation of bran and proteins occurs during fermentation less alcohol side-effects to ethanol. this leads to to a high quality raw alcohol and thus reduced the distillation and rectification effort. The efficiency of used Energy is recovered to ethanol by the method of use a mash almost completely freed from solids, improved.

To the inventive method can by the distillation, rectification and dehydration water obtained recycled and returned to the process.

• a) Quellenlassen des Getreides,
• b) Mahlen des gequollenen Getreides in einer Luftwirbelmühle, so das 90% der Partikel des Mahlgutes eine Teilchengröße von 200 μm erreichen,
• c) Abtrennen der Kleie vom Mahlgut mit einer Siebanlage,
• d) Abtrennen von Proteinen durch einen Dekanter und Trocknen der Proteine,
• e) Fermentieren der von Kleie und Proteinen abgereicherten Stärke mit einem Mikroorganismus, vorzugsweise einer Hefe, und
• f) Abtrennen des Mikroorganismus,
• g) wobei das durch die Fermentation entstandene CO₂ in aufgefangen und ggf. gereinigt und verflüssigt wird,
• h) Abtrennen von Ethanols aus der in Schritt f) erhaltenen Ethanol/Wasser-Lösung, vorzugsweise durch Destillation und
• i) optional Absoluieren des erhaltenen Ethanols durch ein Pervaporationsverfahren.

The invention accordingly relates in particular to a process for the production of ethanol from cereals, comprising the steps:

• a) sourcing the cereals,
• b) grinding the swollen cereal in an air fluidizing mill so that 90% of the particles of the ground material reach a particle size of 200 μm,
• c) separating the bran from the material to be ground with a sieve,
• d) separating proteins by a decanter and drying the proteins,
• e) fermenting the starch depleted of bran and proteins with a microorganism, preferably a yeast, and
• f) separating the microorganism,
• g) wherein the CO ₂ produced by the fermentation is collected and optionally purified and liquefied,
• h) separating ethanol from the ethanol / water solution obtained in step f), preferably by distillation and
• i) optionally, absoluting the obtained ethanol by a pervaporation method.

In Fermentation process, in particular for the production of ethanol in a method according to the invention as above is the preparation of suitable sugar solutions as fermentable starting materials a recurring problem. As a disadvantage conventional sugar solutions in particular considered that a high proportion of non-recyclable waste the fermentation and a high proportion of stillage in a subsequent Distillation is obtained. Another task was therefore sugar solutions as starting materials for fermentations and preferably subsequent distillations and corresponding fermentation and to provide distillation processes with which the disadvantages of Prior art can be avoided or reduced.

• aa) Herstellen oder Bereitstellen einer Stärkemilch,
• ab) thermisches Verflüssigen der Stärke der Stärkemilch,
• ac) Spalten der Stärke zum Gewinnen Mono-, Di- und/oder Oligosacchariden,
• ad) Abtrennen von Fetten, Ölen und Proteinen aus der in Schritt ac) erhaltenen Stärkemilch, und
• ae) Gewinnen der ersten Zuckerlösung als Permeat einer ersten Membranfiltration der in Schritt ac) und/oder ad) erhaltenen Stärkemilch.

Therefore, according to the invention, there is also provided a method for producing a first sugar solution, comprising the steps:

• aa) producing or providing a starch milk,
• ab) thermally liquefying the starch of the starch milk,
• ac) columns of starch for obtaining mono-, di- and / or oligosaccharides,
• ad) separating fats, oils and proteins from the starch milk obtained in step ac), and
• ae) obtaining the first sugar solution as permeate of a first membrane filtration of the starch milk obtained in step ac) and / or ad).

The first sugar solution is largely free of hard-to-ferment ingredients and is therefore particularly suitable for avoiding or reducing the onset of a distillation stillage. The The first sugar solution is sterile if the method is suitable. In addition, the production of the first sugar solution does not result in waste that is difficult to dispose of; instead, the separated fats, oils and proteins can be used as feed.

Prefers Here is a method in the first sugar solution Contains not more than 0.01% by weight of starch, wherein the first sugar solution is particularly preferably starch-free is.

Especially Preferably, the first sugar solution comprises a proportion of 15-25% by weight of glucose, more preferably from 18-22 Wt .-% glucose. Such sugar solutions are particularly easy fermented residue-free for ethanol production.

To the further reducing the proportion not converted to sugar solution Starch milk ingredients and to enlarge the sugar yield, it is preferred, a first retentate substream the first membrane filtration of the starch milk to be cleaved in step ac) for performing step ac). Preferably are from the starch milk used in the membrane filtration 25-30% by volume, preferably 27% by volume, as retentate substream for performing step ac).

• ba) Herstellen oder Bereitstellen einer Pentosanfraktion einer Stärkemilch,
• bb) optional Aufkonzentrieren der Pentosanfraktion,
• bc) Spalten von Zellulose und/oder Hemicellulose der Pentosanfraktion, vorzugsweise unter Säurezusatz und besonders bevorzugt unter Säurezusatz in einem Entspannungsverdampfer,
• bd) Abtrennen von Fetten, Ölen und Proteinen aus der in bd) erhaltenen Pentosanfraktion, und
• be) Gewinnen der zweiten Zuckerlösung als Permeat einer dritten Membranfiltration der in Schritt bc) und/oder bd) erhaltenen Pentosanfraktion.

Also according to the invention, a method is provided for producing a second sugar solution, comprising the steps:

• ba) preparing or providing a pentosan fraction of a starch milk,
• bb) optionally concentrating the pentosan fraction,
• bc) columns of cellulose and / or hemicellulose of the pentosan fraction, preferably with addition of acid and particularly preferably with addition of acid in a flash evaporator,
• bd) separating fats, oils and proteins from the pentosan fraction obtained in bd), and
• be) recovering the second sugar solution as permeate a third membrane filtration of the obtained in step bc) and / or bd) Pentosanfraktion.

The Second sugar solution is also largely free from heavy fermentable components and is therefore particularly suitable avoid or reduce the onset of distillation stillage. This is particularly advantageous because the for producing the second Sugar solution pentosan fraction used a high Proportion of substances which are not or hardly fermentable, in particular Cellulose and / or hemicellulose contains. The second sugar solution is sterile with a suitable embodiment of the method. moreover none in the preparation of the second sugar solution difficult to dispose of waste; instead you can the separated fats, oils and proteins as feed be used.

Prefers is a process in the second sugar solution one Contains not more than 0.01% by weight of starch, wherein the first sugar solution is particularly preferably starch-free is.

Especially Preferably, the second sugar solution comprises a portion from 15-25% by weight of glucose, more preferably from 18-22 Wt .-% glucose. Such sugar solutions are particularly easy fermented residue-free for ethanol production.

In A particularly preferred method is a retentate substream the first membrane filtration of the pentosan fraction to be cleaved in step bc) Performing step bc) is added. Through this process design the yield of sugar solution can be measured by the total amount used starch milk and pentosan fraction advantageous increase. Preferably, from in the first Membrane filtration used starch milk 1-5 Vol .-%, preferably 3 vol .-%, as a retentate substream for performing from step bc).

Especially preferred are those methods for producing a first or second sugar solution in which the starch milk in step ac) and / or the pentosan fraction in step bc) saccharification enzymes be added. The saccharification enzymes support Advantageously, splitting the starch, cellulose and / or Hemicellulose constituents to more easily fermentable sugars.

To the Making the starch milk in step aa) of the main stream and / or for producing a pentosan fraction in step ba) of Side stream is particularly preferably one in a three phase decanter used purified starch milk. Such mainstream and By-pass fractions of a starch milk can be with easily produce conventional three-phase decanters. Of the The term "main stream" refers to a starch milk with the following composition (average data, in% by weight): 31% starch, 0.8% proteins, 0.3% fats, 0.1% pentosans, 0.2% salts and minerals, 0.2% cellulose, balance water. The expression "Nebenstrom" refers to a Pentosanfraktion with the following Composition: (average data, in% by weight): 5% starch, 2% proteins, 0.3% fats, 1% pentosans, 0.3% salts and minerals, 2% cellulose, balance water.

It is furthermore preferred if a purified starch is taken up in an aqueous solvent as described above and then in a three-phase decanter as described above is purified to obtain purified starch milk and / or a Pentosanfraktion. The purified starch of the present invention described above is particularly advantageously purified from constituents which are difficult to ferment, thus assisting the avoidance of stillage in a distillation and the avoidance of waste in the production of the easily fermentable sugar solution.

Especially a second retentate substream of the first membrane filtration is preferred the pentosan fraction to be cleaved in step bc) for carrying out from step bc). In this case, preferably of 100 t total pentosane fraction used in membrane filtration 30 t for performing step bc) is returned.

• ca) Bereitstellen einer ersten oder zweiten Zuckerlösung wie oben beschrieben,
• cb) Durchführen der Fermentation zum Herstellen einer Fermenterbrühe,
• cc) Abtrennen von Mikroorganismen aus der Fermenterbrühe zum Herstellen einer Maische,
• cd) Reinigen der in Schritt cc) erhaltenen Maische durch Membranfiltration zu einem Permeat.

With the sugar solutions prepared or prepared according to the invention, a particularly advantageous fermentation process can be carried out. The fermentation process, preferably for the production of ethanol, comprises the steps:

• ca) providing a first or second sugar solution as described above;
• cb) carrying out the fermentation to produce a fermenter broth,
• cc) separating microorganisms from the fermenter broth to produce a mash,
• cd) purifying the mash obtained in step cc) by membrane filtration to a permeate.

The thus obtained permeate is completely or largely free of malodorous constituents and therefore particularly suitable for carrying out a distillation, in particular for ethanol production.

One Part of the microorganisms separated in step cc) in step ca) provided sugar solution is preferably for Performing step cb) supplied, and a other part of the microorganisms separated in step cc) preferably dried to a microorganism dry product. In this way, the amount of non-fermented substances can continue be reduced.

Especially it is preferred in a mainstream fermentation process a ferment the first sugar solution as described, in a secondary sugar fermentation process, a second sugar solution as described will ferment, and in each case in step cd) obtained permeates. That way you can Both fermentations optimal for achieving a high fermentation product yield (In particular ethanol yield) are controlled.

• da) Durchführen einer Destillation zum Herstellen eines Destillationsproduktdampfes,
• db) Komprimieren eines ersten Destillationsproduktdampf-Teilstroms in einem Brüdenverdichter, Betreiben eines Wärmetauschers mit dem komprimierten Teilstrom zum Gewinnen von Wärme zum Betreiben der Destillation und zum Gewinnen eines Kondensats als Rücklauf für die Destillation, und/oder
• dc) Aufreinigen eines zweiten Destillationsproduktdampf-Teilstroms in einem Permeations- oder Pervaporationsschritt zum Gewinnen eines gereinigten Destillationsproduktes und eines abgereicherten Destillationsproduktdampf-Teilstroms, wobei der abgereicherte Destillationsproduktdampf-Teilstrom in einem Brüdenverdichter komprimiert und in einem Wärmetauscher zum Gewinnen von Wärme zum Betreiben der Destillation und zum Gewinnen eines Kondensats als Rücklauf für die Destillation eingesetzt wird.

A preferred distillation method according to the invention comprises the steps:

• da) carrying out a distillation to produce a distillate product vapor,
• db) compressing a first distillation product vapor substream in a vapor compressor, operating a heat exchanger with the compressed substream to recover heat to operate the distillation and recover a condensate as the reflux for the distillation, and / or
• dc) purifying a second distillation product vapor substream in a permeation or pervaporation step to recover a purified distillation product and a depleted distillate vapor substream wherein the depleted distillate vapor substream is compressed in a vapor compressor and heated in a heat exchanger for recovering distillation and Recovery of a condensate is used as reflux for the distillation.

With the distillation process according to the invention, in which in particular a permeate of an inventive Fermentation process can be distilled, is advantageous recovered a lot of heat, leaving only a minimal Heating the distillation apparatus used needed becomes. Furthermore, the operating conditions of the permeation or Pervaporationsschrittes each to win by distillation Product be optimally adapted.

at an ethanol distillation by means of an inventive Distillation method, the distillation product vapor one Ethanol content of preferably at least 80 wt .-%, more preferably at least 85% by weight, and more preferably 85-90% by weight.

The Invention will be described below with reference to the embodiments described in more detail, without the examples, the scope restrict the claims:

As in 1 shown, the grain, which is preferably stored in a silo, introduced into the process. The grain is ground in an air vortex mill and the bran removed by deposition. Proteins are decanted and separated.

By this procedure will give a starchy milk which is the contains total usable carbohydrates of the crop. The non-alcohol-forming components are thus before the fermentation process separated. This starch milk is liquefied with enzymes and saccharified.

This starch milk serves as a substrate for a fermentation, to start the fermentation Yeast and nutrients added.

The Fermentation produces an alcoholic mash, from the after completion the fermentation the separated yeast is separated and separated. This will provide a feed that is very good for the feeding of animals, especially cows, Pigs, horses, chickens etc. can be used.

The CO ₂ produced in the fermentation is washed and purified from other gases, it is separated and condensed in a conventional manner.

The thus obtained ethanol / water solution becomes a stand the usual technique in a distillation plant used for the extraction of raw alcohol. In the distillation is formed crude alcohol, which by rectification to bioethanol or Neutral alcohol is purified. The complete drainage is done by a membrane sieve method. The purity of the thus obtained product can be up to 99.6 vol.%.

2 shows a further, more detailed flow diagram of an inventive processing method for ethanol production.

By a three-phase decanter will make the starch milk in three Fractions, one of which forms the proteins known in the art Be prepared and cleaned; in the This fraction still contained starch is by washing separated and further processed in the main stream. The second one is a Pentosanfraktion separated, in addition to strength almost contains all residues, pentoses, cellulose and hemicelluloses and processed as a side stream.

The third fraction forms a 1 purified starch milk, the as the main stream is processed further. Before fermentation Both the main and the side stream become the solids separated, so that in distillation only the so-called Lutterwasser accumulates, for the most part to Anteigen of the flour and used again for dilution in the process becomes.

Processing of the main stream

The Starch milk separated by the three-phase decanter becomes for liquefaction and solution of starch heated in a series of heat exchangers in several stages, being their viscosity with the temperature first rises sharply, goes through a maximum and drops again. The starch milk is transferred into Zwischenbehältem a period of 0.5 to 3 h, preferably 1 to 1.5 h at a Temperature maintained between 80 to 90 ° C, preferably 85 ° C, until the viscosity is sufficiently lowered. In a second stage, it is then at a temperature of 85 to 115 ° C, preferably 102 to 105 ° C, and transferred a period of 0.5 to 3 hours, preferably 40 to 80 minutes at held at this temperature, being sterilized and all Microorganisms are killed. The heating of the last Stage of the heat exchanger takes place with steam in the process before located heat exchangers are used for heat recovery with the already liquefied hot starch milk heated, which is cooled. Both in front of the entrance in the stage of the first heat exchangers as well as in the intermediate stages and before the last stage, suitable liquefaction enzymes be added. After liquefaction, the on 30 to 40 ° C, preferably about 35 ° C, cooled Starch solution, if appropriate for lowering the Content of dry matter diluted and it will be suitable Added to saccharification enzymes. The solution is over a period of 1 to 20 hours, preferably 2 to 10 hours in containers stored with stirring until the saccharification process is complete is. The duration of the saccharification process depends on the Type and concentration of the enzymes used. In a centrifuge are still contained in the saccharified starch solution Fats and the and and the remaining proteins separated and removed from the process.

In a subsequent first membrane filtration are the Verzuckerungsenzyme and not completely degraded Starch fragments and oligosaccharides retained, the purified and sterile sugar solution obtained as permeate has a glucose dry content of preferably 18-22 wt .-% up and, if necessary after intermediate storage, to the main Fermentation led.

The Retentate membrane filtration is divided into two streams divided up. A first partial stream is added to the inlet of the saccharification attributed to the concentration of enzymes in this process step to increase and the saccharification in optimal time with a minimal addition of fresh enzymes perform. Contains the retentate of membrane filtration in addition to enzymes and fragments of the starting strength in addition, pentosans and hemicelluloses, which are due the used saccharification enzymes are not or only partially split. To a concentration of these substances by the return to avoid the saccharification, a second partial flow of Retentats of the first membrane stage, optionally after an intermediate storage, led into the sidestream.

The fermentation of the sterile sugar solution of the main stream is carried out in closed stirred tanks of known type. You are with one Cooling jacket for removing the heat generated during fermentation and with connections for cleaning and sterilization, for supplying the substrate, nutrient solution, compressed air, fresh and recycled yeast milk and for the removal of the fermented mash and the resulting carbon dioxide. The latter is washed in a column with water before it is released into the atmosphere or sent to further use.

Several Fermenters can be operated both in series and in parallel become. By proper operation and selection of the yeast can at a temperature between 28 and 35 ° C, preferably be operated at 32 ° C, with a high concentration the yeast, preferably by the use of flocculating yeasts and their repatriation. This not only shortens the fermentation time become, it also the education primary and secondary By-products suppressed and a higher yield and purity of the final product achieved.

To Termination of the fermentation becomes a mash with an alcohol content from 6 to 14%, preferably 8-12% and a DM content obtained in yeast between 5 and 8%. The mash is centrifuged, The clear water with a yeast content of less than 0.5% is in one second membrane stage further purified, the only of water, Alcohol and some dissolved minerals permeate stored in intermediate tanks and fed to the distillation column. The retentate of this membrane stage becomes the entrance of the centrifuge guided. A partial flow of the thick phase from the centrifuge, the yeast milk, with a TS content of 18 to 20% is used to separate the Alcohol after preheating in a vacuum evaporator at a temperature of 44 to 48 ° C to a residual content Alcohol of less than 2% evaporated, a second partial stream is returned directly to the fermentation. Of the Vapors from the evaporation is compressed and heated the vacuum evaporator, the condensate is combined with the clear water. A portion of the evaporated thick phase is diluted with water and, optionally after addition of nutrients, as yeast milk returned to the mainstream fermentation, the other portion is separately further evaporated and dried and forms as dry yeast another by-product.

Processing of the secondary flow

to Use of the fermentable substances contained in it separated by the three-phase decanter, very diluted Pentosanfraktion, optionally after intermediate storage, preheated and in a flash evaporator at a temperature of 70 to 85 ° C, preferably 74 to 80 ° C, concentrated. The resulting steam is through a vapor compressor condenses and serves to heat the evaporator, the cooled Condensate is used as process water.

Of the second partial stream of the retentate from the first membrane filtration after the saccharification of the main stream with the by evaporation preconcentrated side stream combined and in several stages a temperature of 110 to 160 ° C, preferably 125 to Heated to 150 ° C and for 10 to 60 min, preferably 20 to 40 minutes, at this temperature and a pressure of 3 to 6 bar, preferably 4 to 5 bar held. Then it will be abrupt to a pressure of 150 to 250 mbar in a flash tank relaxed. The resulting steam is via a vapor compressor compressed and also serves to heat the upstream Evaporator,.

By the high temperature and the sudden relaxation will be the in the sidestream fraction contained cellulose and hemicellulose and split the enzymes which are not split into monosaccharides are also eliminated Strength fragments further reduced. By adding of acid during heating can this process be accelerated.

in the lower part of the relaxation tank will be an already partially saccharified sterile solution of the secondary stream with a TS content of 30 to 35%. To the complete Saccharification is added to enzymes and the solution in Containers over a period of 1 to 20 h, preferably stirred for 2 to 10 h. She will be following centrifuged to remove fats and proteins. In, if necessary after an intermediate storage following third membrane filtration is obtained as permeate a sterile sugar solution, the contains glucose and other hexoses and pentoses and is led to the sidestream fermentation. The retentate from the membrane filtration of the secondary stream contains the separated Verzuckerungsenzyme, it is centrifuged to non-fermentable To disperse solids and into the saccharification containers led back.

The fermentation of the sterile sugar solution of the secondary stream takes place in closed stirred tanks of a known type, corresponding to those of the fermentation of the main stream. They are provided with a cooling jacket to dissipate the heat generated during fermentation and with connections for cleaning and sterilization, for supplying the substrate, nutrient solution, compressed air, fresh and recycled yeast milk and the removal of the fermented mash and the resulting carbon dioxide. The latter is washed in a column with water before it is released into the atmosphere or another use is supplied.

Several Fermenters can be operated both in series and in parallel become. By proper operation and selection of the yeast can at a temperature between 28 and 35 ° C, preferably be operated at 32 ° C, with a high concentration the yeast, preferably by the use of flocculating yeasts and their repatriation. This not only the It will also shorten the fermentation time suppressed primary and secondary by-products and a higher yield and purity of the final product reached. In the selection of yeasts are preferable to those can also ferment pentoses to alcohol.

The Mash is centrifuged, the clear water with a yeast content of less than 0.5% is further purified in a fourth membrane stage, that only from water, alcohol and some dissolved minerals existing permeate stored in intermediate tanks and with the corresponding cleaned mash of the main stream led to the distillation column. The retentate of this fourth membrane stage becomes the entrance of the centrifuge guided. A partial flow of the thick phase from the centrifuge, the yeast milk, with a TS content of 18 to 20% is used to separate the Alcohol after preheating in a vacuum evaporator at a temperature of 44 to 48 ° C to a residual content Alcohol of less than 2% evaporated, a second partial stream is returned directly to the sidestream fermentation. The vapor from the evaporation is compressed and heated the vacuum evaporator, the condensate is combined with the clear water. A portion of the evaporated thick phase is diluted with water and recycled as yeast milk into the sidestream fermentation, the other proportion is the corresponding portion of the main stream separately further evaporated and dried and forms as a dry yeast another by-product.

Distillation:

at Distillation or rectification, the product falls on Head of the distillation column in vapor form, the steam is generally subsequently condensed, a part is given as reflux to the top of the column, the other part represents the desired product. The heat content the head steam is usually lost, its temperature is lower as the at the bottom of the columns, so he can not directly to the heating the columns are used. The skilled person is aware that in special cases the head steam can be compressed in a Bruderverdichter can, by the compression its pressure and its temperature rise to such a level that he now has to heat the swamp can serve the column.

Has the steam at the top of the columns is an approximate azeotropic Composition, it is often directly into a steam permeation plant directed. So that the steam for the Dampfpermeationsanlage has optimum temperature, the column is often at operated at a higher pressure than atmospheric pressure. Mostly there is saturated vapor, with certain membranes the steam can also be overheated. Also the product steam the steam permeation unit generally does not have a sufficient temperature, to heat the swamp of the columns.

It has now surprisingly revealed that too the product vapor of the vapor permeation plant by a vapor compressor compressed and thus brought its temperature to such a level can be that the bottom of the column heated with the product vapor can be. This makes it possible to have a combination of a distillation or rectification column with a downstream To operate steam permeation with a minimum of heating energy and to use the heat otherwise obtained in the product vapor.

The below described method of drainage or Absolutierung of ethanol can also be used for the separation of water from others, forming azeotropes with water Components. These can be the higher alcohols such as 2-propanol, butanol or the pentanols, but also ketones such as butanone, esters such as ethyl esters or ethers. For It is further clear to the person skilled in the art that ternary or higher Azeotropic dehydrated in the same way advantageous with the method can be. Furthermore, it is clear that when using suitable Membranes can also be separated purely organic mixture, as examples may be the separation of methanol from mixtures with its Esters or with acetone, or the separation of aromatics we benzene from its mixtures with aliphatic hydrocarbons.

The distillation column is operated in such a way that a vaporous ethanol-water mixture of approximately azeotropic composition is obtained at the top. It depends on the requirements of the purity of dehydrated ethanois how much impurities must be removed. If the produced alcohol z. For example, as fuel, it is often sufficient to distill only to an ethanoic content of about 85% by weight and to remove the residual water through the membrane unit, otherwise it must be distilled closer to the azeotrope. The resulting steam is divided into two partial streams. A partial stream is compressed in a vapor compressor and condensed in a heat exchanger which heats the bottom of the column. The hot condensate is added at the top of the column as reflux for the rectification. Of the second substream from the top of the column is passed into a vapor permeation unit and the water is removed to the specified residual content. The operating conditions of the Dampfpermeationsanlage with respect to pressure and temperature are given by the corresponding operating conditions, and can be chosen over this in a wide range. The dewatered vaporous product is compressed in a second vapor compressor and heated via another heat exchanger, the bottom of the column. The heat content of the hot condensate is used to preheat the feed to the column. In this way, the majority of the thermal energy required for the operation of the column is recovered from the overhead vapor of the column and used.

One An essential advantage of the method is that both partial streams compacted separately and their pressures and temperatures separated can be regulated. While it is possible the entire steam at the top of the column in a vapor compressor to compress and so on for heating the column to reach required temperature, and only then into one Partial flow for the return and a second for to divide the steam permeation plant. Then the Dampfpermeationsanlage but at the time required for the heating of the column bottom Temperature operated, giving the freedom to choose the operating conditions severely limits. Furthermore, the steam undergoes the Flow through the Dampfpermeationsanlage a certain Pressure drop whereby its temperature of that of the partial stream for will deviate from the return. Therefore, such an interconnection from a column, a vapor permeation and a vapor compression less preferred.

• 1 Energieverbrauch Destillation/Rektifikation/Dehydrierung: – Dampfbedarf: 1590 kg/t Ethanol × 2,10 MJ/kg = 3339 MJ/t Ethanol – Strombedarf: 490 kWh/t Ethanol × 3,6 MJ/kg = 1764 MJ/t Ethanol Energieverbrauch insgesamt = 5103 MJ/t Ethanol.
• 2 Energieverbrauch der Nebenproduktproduktion: – Dampfbedarf: 1410 kg/t Ethanol × 2,10 MJ/kg = 2961 MJ/t Ethanol; – Strombedarf: 300 kWh/t Ethanol × 3,6 MJ/kg = 1080 MJ/t Ethanol. Energieverbrauch insgesamt = 3041 MJ/t Ethanol.
• 3 Als Energieverbrauch des Gesamtprozess ergibt (3.1 und 3.2) sich somit: – Dampfbedarf von 3000 kg/t Ethanol × 2,02 MJ/kg = 6300 MJ/kg – Stromverbrauch von 790 kWh/t Ethanol × 3,6 MJ/kg = 2844 MJ/kg.

According to the invention, the overall method has an energy requirement which is composed of:

• 1 Energy consumption Distillation / rectification / dehydrogenation: - Steam requirement: 1590 kg / t ethanol × 2.10 MJ / kg = 3339 MJ / t ethanol - Electricity requirement: 490 kWh / t ethanol × 3.6 MJ / kg = 1764 MJ / t ethanol Total energy consumption = 5103 MJ / t ethanol.
• 2 Energy consumption of by-product production: - steam demand: 1410 kg / t ethanol × 2.10 MJ / kg = 2961 MJ / t ethanol; - Electricity consumption: 300 kWh / t ethanol × 3.6 MJ / kg = 1080 MJ / t ethanol. Total energy consumption = 3041 MJ / t ethanol.
• 3 As energy consumption of the overall process (3.1 and 3.2) thus results: - Steam demand of 3000 kg / t ethanol × 2.02 MJ / kg = 6300 MJ / kg - Electricity consumption of 790 kWh / t ethanol × 3.6 MJ / kg = 2844 MJ / kg.

The Production of all products thus requires energy consumption of 9144 MJ / t ethanol.

• – Dampfbedarf für die Destillation/Rektifikation, Absolutierung, Trocknung der Getreideschlämpe,
• – 7000 kg/t Ethanol × 2,10 MJ/kg = 14700 MJ/t Ethanol,
• – Strombedarf für die Destillation/Rektifikation, Absolutierung, Trocknung der Getreideschlämpe,
• – 330 kWh/t Ethanol × 3,6 MJ/kg = 1188 MJ/t Ethanol,

The energy balance of conventional methods, on the other hand, gives:

• Steam requirement for the distillation / rectification, absolution, drying of the grain slurry,
• - 7000 kg / t ethanol × 2.10 MJ / kg = 14700 MJ / t ethanol,
• - Electricity required for the distillation / rectification, graduation, drying of the grain slurry,
• 330 kWh / t ethanol × 3.6 MJ / kg = 1188 MJ / t ethanol,

This corresponds to a total energy consumption of 15888 MJ / t ethanol.

It shows that the underlying process 6744 MJ / t ethanol uses less energy than the state of the art Method. This corresponds to a reduction in energy consumption by 43%. The invention requires the preparation of ethanol from cereals only about 57% of the energy needed to carry out conventional Process needed to produce ethanol from grain become. This demonstrates the advantages of the invention of the method for Production of bioethanol, gluten, yeast and bran.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - AT 398981 [0007]
• DE 2944483 C2 [0007]
• - DE 3007138 C2 [0007]
• - US 6569653 B1 [0007]

Claims (25)

Process for the preparation of purified starch, comprising the steps: i) grinding of starchy Grain in an air vortex mill to a cornstarch, so that 90% of the particles of flour have a particle size from 150 to 250 μm, ii) separating bran from the flour, and then iii) separating proteins from the flour. The method of claim 1, further comprising the processing the separated proteins to gluten. Purified starch, producible after one Method according to one of the preceding claims. A process for producing ethanol, comprising the steps: iv) Provide purified starch according to claim 3, v) fermenting the starch provided in step iv) by microorganisms to a fermenter broth, optionally after liquefying the starch, vi) manufacture a mash by separating microorganisms from the fermenter broth, vii) Separating ethanol from the mash. Method according to claim 4, characterized in that that the ethanol is separated by distillation from the fermenter broth becomes. Method according to one of claims 4 to 5, characterized in that the separated ethanol by a Pervaporation process is drained. The method of any one of claims 4 to 6, further comprising capturing CO ₂ released during the fermentation. Method for producing a first sugar solution, comprising the steps: aa) manufacture or provide a Starch milk, ab) thermal liquefaction the strength of the starch milk, ac) columns of Starch for obtaining mono-, di- and / or oligosaccharides, ad) Separate fats, oils and proteins from the in step ac) obtained starch milk, and ae) winning the first Sugar solution as permeate of a first membrane filtration the starch milk obtained in step ac) and / or ad). Method according to claim 8, characterized in that that the first sugar solution is starch free. Method according to claim 8 or 9, characterized that the first sugar solution accounts for 15-25 Wt .-% glucose. Method according to one of claims 8 to 10, characterized in that a first retentate substream of the first Membrane filtration of the starch milk to be cleaved in step ac) for performing step ac) is added. Method for producing a second sugar solution, comprising the steps: ba) producing or providing a Pentosan fraction of a starch milk, bb) optional concentration the pentosan fraction, bc) columns of cellulose and / or hemicellulose Pentosanfraktion, preferably with addition of acid, bd) Separating fats, oils and proteins from that in bd) obtained pentosan fraction, and be) recovering the second sugar solution as permeate a third membrane filtration in step bc) and / or bd) obtained Pentosanfraktion. Method according to claim 12, characterized in that that the second sugar solution is starch free. Method according to one of claims 12 to 13, characterized in that the second sugar solution a Contains 15-25 wt .-% glucose. Method according to one of claims 12 to 14, characterized in that a retentate substream of the first membrane filtration the pentosan fraction to be cleaved in step bc) for carrying out Step bc) is added. Method according to one of claims 8 to 15, characterized in that the starch milk in step ac) and / or the pentosan fraction in step bc) saccharification enzymes be added. Method according to one of claims 8 to 16, characterized in that for producing the starch milk in step aa) the main stream and / or for producing a Pentosanfraktion in step ba) the side stream one in a three phase decanter purified starch milk is used. Method according to claim 17, characterized in that that a purified starch according to claim 3 in an aqueous Solvent and then in a three-phase decanter is purified to obtain a main stream and / or a side stream. Method according to one of claims 17 to 18, characterized in that a second retentate substream of first membrane filtration of the pentosan fraction to be cleaved in step bc) for performing step bc) is added. Sugar solution, manufacturable or made according to one of claims 8 to 19. Fermentation process, preferably for the manufacture of ethanol, comprising the steps: ca) providing a first or second sugar solution according to claim 20, cb) Carrying out the fermentation to produce a fermenter broth, cc) Separating microorganisms from the fermenter broth for Making a mash, cd) purifying the product obtained in step cc) Mash by membrane filtration to a permeate. Fermentation process according to claim 21, characterized in that a part of the microorganisms separated in step cc) the sugar solution provided in step ca) for performing from step cb), and another part of the in step cc) separated microorganisms to a microorganism dry product be dried. Fermentation process according to one of the claims 21 to 22, characterized in that in a mainstream fermentation process a first sugar solution according to claim 20 is fermented, in a secondary sugar fermentation process, a second sugar solution is fermented according to claim 20, and in each case in step cd) obtained Permeate be united. Distillation process comprising the steps: there) Performing a distillation to produce a distillate product vapor, db) Compressing a first distillation product vapor substream in a vapor compressor, operating a heat exchanger with the compressed partial flow for obtaining heat for operating the distillation and recovering a condensate as reflux for the distillation, and / or dc) Purifying a second distillation product vapor substream in a permeation or pervaporation step to obtain a purified distillation product and a depleted distillation product vapor substream, wherein the depleted distillation product vapor substream is in a vapor compressor compressed and in a heat exchanger for winning Heat to operate the distillation and to win a Condensate used as reflux for distillation becomes. Distillation method according to claim 24, characterized characterized in that the distillation product vapor has an ethanol content of at least 80% by weight.