DE102008004971A1 - Substantially and energetically optimized bioethanol production process - Google Patents

Abstract

The invention relates to an improved economical method and a corresponding apparatus for producing bioethanol from cereals and lignocellulose-containing biomasses, in which a production line for grain and a timely operated production line lignocellulose up to the saccharification stage and a specific fermentation depending on the biomass used and then the streams are passed into a common distillation and dewatering step.

Description

The The invention relates to a method and a device for generating of bioethanol from cereals and lignocellulose-containing biomasses according to the preambles of the claims 1 and 10.

raw materials for bioethanol production basically constitute all plants that have a correspondingly high content of fermentable Contain substances.

in the European economic area, these are primarily the Cereal wheat, rye and corn; Tritikale, barley, oats and millet are rarely used for this purpose. Furthermore, turns with the waste product of the sugar industry, the molasses, a low-cost raw material in addition to sugar beets and potatoes. In other latitudes, rice, sugar cane and cassava used extensively for alcohol production.

Great hopes are placed in this context also in the use or implementation of lignocelluloses. Lignocellulose consists of cellulose (C ₆ sugar, glucose), hemicellulose (C ₅ and C ₆ sugars, mainly xylose and mannose) and lignin (polymer of aromatic components); Cellulose and hemicellulose can be fermented to ethanol after appropriate pretreatment and hydrolysis; the remaining, non-fermentable fraction can be thermally converted to electricity and heat.

"Features of promising technologies for pre-treatment of lignocellulosic biomass" by Nathan Mosier and others, published in Bioresource Technology 96 (2005), page 673-686 , Elsevier publisher gives a good overview of the possibilities of pretreatment of lignocellulosic, as they are common at the moment.

Sun and Cheng have in their essay "Hydrolysis of lignocellulosic materials for ethanol production: a review", published in Bioresource Technology 83 (2002), pages 1-11, Elsevier Verlag reviewed the hydrolysis of lignocellulosic material for bioethanol production.

It is well known, for example from the protection literature DE 103210607 A1 . DE 10327954 64 . EP 330686 B1 . US 20050026261 A1 To win organic alcohol from cereals or alternatively according to the protective literature WO 2001060752 A1 . WO 2003049538 A2 To use lignocellulose to extract bioethanol. In the cases mentioned above, which is also the gray literature, a digestion of the lignocellulosic biomass by hydrolysis in an acidic medium is generally used as a priority, although already in the DE 3428661 C2 also describes the hydrolysis of comminuted and solvent-milled lignocellulosic biomass with high-tension water vapor in a Dispergerreaktor. However, a disclosure of such hydrolyzed biomass in combination with saccharified and fermented cereals - bioethanol - to work is not apparent.

From the EP 105937 B1 Also already known is a self-contained process for the production of alcohol from lignocellulosic material by a combination of process steps. The starting material is treated with sulfur dioxide and water under heat and pressure by the introduction of steam, mixed with alkaline solution to dissolve and remove the lignin from the cellulose content and sufficient water evaporated from the dissolved lignin for a fuel, which in turn is used as an energy source for steam generation becomes. The hydrolyzed cellulose is fermented to alcohol. In this respect, this is a single-purpose plant for the production of alcohol from lignocellulosic biomass.

In addition, two other protection documents are known in which it is mentioned facultatively that different end products may be incurred. First, the mentioned WO 1098041646 A1 a process for the utilization of biomass from agricultural crops, which is comminuted and pressed into a low-solids and a high-solids phase and separated, wherein the high-solids phase is treated with steam in the overpressure. The final product is ethanol, pulp and biogas. According to the WO 2007009463 A2 Carbonaceous material is to be converted to ethanol by a continuous hydrothermal treatment and without the addition of chemicals. The resulting liquid and fiber fractions should be separated after this pretreatment. It is stated that the final product is fuel ethanol, animal feed and electricity or electricity.

all Previous proposals have in common that they are special Equipment for the production of bioethanol either from cereals or from lignocellulose. But such lines are not interoperative are coupled with each other.

It has already been mentioned in the US patent application US 2007/0161095 A1 that, from the simultaneous use of biomasses, lignocellulose and agricultural products such as cereals as starting raw materials receive various end products, for example biodiesel but also nanocomposites or electricity. However, the treatment should essentially be carried out through the participation of ionic liquids and gases with specific reaction conditions. A simultaneous parallel operation of a working bi oethanolanlage and a lignocellulosic converting ethanol plant are not mentioned.

It is striking that by the trend to win bioethanol In some areas, either the grain is scarce or seasonal the lignocellulosic materials are not always available are.

From Therefore, the invention is based on the problem of bioethanol production from grain and lignocellulose to optimize.

The Problem is solved by the features of claims 1 and 10 solved. Further developments of the inventions are in the dependent Claims included.

The The first solution to the problem comprises according to the invention Process for processing grain and lignocellulose into bioethanol in a production line for grain and at the same time the production line for lignocellulose up to the saccharification stage and a specific fermentation depending on the biomass used is operated and then the material flows in a common distillation and dehydration step be directed. This initially saves the construction of parallel Distillation and dehydration stages and leaves variable Use of certain amounts of raw materials in one way or another Line for common processing of the applied products and energies.

In A variant may improve the economy from the lignocellulose processing line deducting excess steam from hydrolysis of the biomass and used elsewhere in this production line or for Use deducted in the production line for the grain become.

To the hydrolysis stage in the production line for processing Lignocellulose resulting liquid phase can according to the invention as far as possible separated from a solid phase and the liquid phase of a Biogas plant to be supplied for further optimal recovery.

Also the residues after distillation and dewatering (stillage) can be fed to this biogas plant, in then the still and the hemicellulose rich liquid phase to biogas according to the invention implemented together become.

Preferably the biogas can generate electricity and use the electricity used in the vicinity or the production lines or over a low-pressure gas distribution network mixed with natural gas or city gas become.

The inventive method is preferably so led that lignocellulose in the hydrolysis step is digested so that the hydrolyzed mass a largely neutral pH, preferably in the range pH 5-7 Abandonment of addition of acids or alkalis.

The Procedure allows the two at the same time with each other Operated bioethanol plants with variable amounts of cereals and lignocellulosic biomass are fed, the proportion on lignocellulose, based on the amount of cereal used 1 to a maximum of 50 weight percent. So it can for example, at the same job site of cereal farmers the grain and deliver the straw. On the other hand, any lignocellulosic Biomass are processed.

Preferably For example, the final ethanol concentration in both the processing of Cereals as well as in the processing of lignocellulose before the distillation stage have a final ethanol concentration of 4-19% by volume.

The second solution relates to a device for processing the biomass types of cereals and lignocellulose to bioethanol, in particular to carry out the method described above, wherein at least one each in series arranged device for pretreatment, digestion, Saccharification, fermentation of saccharified masses for each Biomassenart are simultaneously or parallel operable, but by only one for both lines together chargeable distillation device and dewatering apparatus for concentrating the recovered Ethanols supplement finds.

The Device is designed according to the invention that both lines are coupled to a biogas plant for recording of stillage from the distillation equipment and from liquid phases one of the hydrolyzing device for lignocellulose downstream separating device for solids and liquids.

Of the Hydrolysis part of the lignocellulose line can with a discharge device connected by steam to the grain line and with the biogas plant be coupled to a power plant.

The Invention is best characterized by the state of the Technology in widespread manufacturing processes for the Extraction of ethanol from lignocellulose or from cereals with each other compares and contrasts with the present inventive Idea sets, described on the basis of diagrams of the production process.

in the Moment exist three common procedures for the Co-production of ethanol, heat and electricity from lignocelluloses, which, however, are large-scale most diverse, mostly financial backgrounds so far can not be displayed.

Here Large bioethanol plants expect production costs in the future from 0,26 Euro / I (12,4 Euro / GJ) and further reduction by technological Developments to 0.18 Euro / I (8.6 Euro / GJ).

The 1 - 4 show various methods for producing ethanol according to the prior art.

1 shows a biomass process, developed by the "National Renewable Energy Laboratory, USA": Combination of steam pretreatment and mild acid hydrolysis of the hemicellulose fraction and subsequent enzymatic hydrolysis of the cellulose The cellulose hydrolysis and fermentation of xylose and glucose monomers proceed in the same reactor is the genetically modified bacterium Zymomonas mobilis.

2 shows a biomass process, developed by "BC International Corporation, Canada": two-stage acid hydrolysis (first stage releases hemicellulose sugar, second stage cellulose-sugar),

3 shows a biomass process developed by "Logen Corporation, Canada": steam digestion with dilute acid for the release of hemicellulose sugars and subsequent hydrolysis of the cellulose.

This, according to the state of the art, typical ethanol recovery from biomass is in REITH, JH; VEENKAMP, JM and VAN REE, R. (2001): Coproduction of bioethanol, electricity and heat from biomass wastes: potential and R & D issues. ECN, Nedalco, ATO contribution to the First European Conference on Agriculture & Renewable Energy; 6-8 May 2001, RAI, Amsterdam, The Netherlands, on the Internet on 16.01.2008,14: 17: 14 o'clock under http://www.ecn.nl/docs/library/report/2001/rx01011.pdf. In the fermentation, genetically modified microorganisms are probably used.

In 4 are now the main process steps - represented by the general state of the art - for bioethanol production based on grain. After preparation of the raw material according to the process steps shown - storage / purification, grinding, maceration - followed by the conversion of carbohydrates by liquefaction, saccharification - in usable for the microorganism sugar, which are then converted into alcohol by fermentation.

in the subsequent downstream part of the process becomes the alcohol separated (distillation) and further concentrated (drainage) to the end product bioethanol. The residue from the distillation on the other can either be disposed of or further processed in different ways become.

image Figure 5 shows the invention with the same and at one location parallel operated plants for ethanol production Cereals (upper part of the figure) or lignocellulose (lower part of the figure) and their inventive linkage in a schematic flow chart, which shows the individual treatment stages roughly divided.

When Commodity crops can include wheat, corn, rye, triticale, Barley, or sugar-containing raw materials such as sugar beet, Potatoes, molasses, etc. are used as a lignocellulosic raw material Become cereal straw, wood, grass, bagasse, waste paper, green waste etc. recycled. For example, a farmer growing energy crops can both the threshed grain as well as the straw (fresh cornhoppers) to deliver to the plant.

Description of the grain line:

The Korn, here for example triticale, with as high as possible Starch and low protein content is initially milled in a grinder. Depending on the raw material, the grain is on for example, a particle size of smaller 1 mm reduced. In contrast to the state of the art is incurred here Bran not screened.

In the next reactor, the usual mashing of the ground material, followed by the liquefaction in another device. In this case, a mixture of the ground cereal with water and an enzyme solution is achieved. After heating to a predeterminable liquefaction temperature (depending on the type of liquefaction enzyme) of 50-115 ° C and a residence time of 0.5-2.0 h depending on the enzyme concentration, the starch is degraded in a neutral or slightly basic environment. The pH range is adjusted to 5.0-6.5 depending on the liquefaction enzyme to achieve good degradation of the starch in dextrins. The following container is a saccharification device. By addition of saccharification enzyme, the degradation of dextrins into fermentable mono-, di-, and trisaccharides is effected while maintaining a predetermined, monitored pH range, depending on the liquefaction enzyme, pH 4.0-5.5. It is driven, depending on the liquefaction enzyme, at a temperature of 50-65 ° C with a residence time of 1-48 h, depending on the enzyme con concentration.

In the following facility, the fermentation stage, is supplemented of yeast the fermentable sugar in ethanol and carbon dioxide implemented. This process takes 12-50 h and yields one Ethanol end concentration of, for example, 5.0-13.0, preferably in the range of about 4-19, wt .-%. Parallel to the anaerobic Fermentation is a partial flow of yeast in a side stream of a yeast aerobic aerated further container so that enough Yeast cell substance is formed. Thereafter, the biomass in a Promoted distillation device.

Description of the lignocellulosine line:

The abandoned biomass, for example straw, is produced by means of mills and shredders to a particle size crushed by 0.5-10 cm. The shredded straw will suspended in a reactor by addition of water in a suspension, then by direct steam, without the addition of chemicals and alkalis or acids, heated to 160-220 ° C, depending on the types of raw materials and residence times out of 10-120 minutes. This is the major part hemicellulose in solution.

The Lignocellulose is so disrupted in the hydrolysis stage that the hydrolyzed mass a largely neutral pH, preferably in Range pH 5 to 7, has. In the process itself become acids but which is supposed to cause a slight pH drop and does not leave said pH range. This has several Advantages. By dispensing with the addition of chemicals, none, the next process obstructing by-products arise. By doing mentioned pH range is also no or only a small attack to observe the materials of the equipment, what the profitability production through extended life of the plant elevated.

After this hydrolysis, the mass is cooled to the desired saccharification temperature in two flash vessels connected in series. The steam obtained in this way is used, for example, in the grain-based part of the plant, as indicated by a dashed arrow in FIG 5 shown. The use of the extracted steam elsewhere in this plant and in the grain line is also considered to be inventive.

in the next process step is by means of a filter, preferably a suitable belt filter or a screw press, a solid / liquid separation of the cooled mass completed. The liquid phase is pumped into a biogas plant, fed to the solid phase of the saccharification.

The Saccharification is achieved by adding commercially available Cellulases. For saccharification, the residence time of approx. 48 h at the predeterminable temperature of approx. 40-60 ° C, depending on the type of enzyme used. The cellulose becomes enzymatic mined into glucose monomers.

Of the the following process step is the fermentation; after saccharification becomes a standard Saccharomyces fermentation at 30-40 ° C made in a final ethanol concentration of, for example about 5 vol .-% ends.

Expressly due to the frequent rejection of genetically modified biofuels no genetically modified material here and no be used for this purpose microorganisms.

Now the product obtained is pumped to the distillation device.

Description of both lines common procedural steps:

The alcoholic fermented solution from the grain line and the fermented masses from the lignocellulosine line are brought together and in a first stage, a mash column distilled up to about 50% by weight of ethanol.

in the The next step is the resulting ethanol / water mixture then in a rectification device to about 90 wt .-% ethanol concentrated. By means of a further dewatering treatment, for example, entrainer distillation or molecular sieve technologies or pervaporation, the solution is at least 99.0 vol .-% Ethanol further concentrated.

The in these stages accumulating residue, the so-called vinasse, is deducted at the bottom of the mash column and the biogas plant fed. The prior art attempts via sewage sludge To win methane or to infiltrate the vinasse in animal feed.

According to the invention however, the whole vinasse in the biogas plant with the hemicellulosic Liquid phase from the Lignozellulosenlinie converted into biogas. The resulting biogas will then continue to be used to generate electricity. The process from biogas production can - as for be known - so given or another, be supplied to aerobic treatment.

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

• - DE 103210607 A1 [0007]
• - DE 1032795464 [0007]
• - EP 330686 B1 [0007]
• US 20050026261 A1 [0007]
• - WO 2001060752 A1 [0007]
• - WO 2003049538 A2 [0007]
• - DE 3428661 C2 [0007]
• - EP 105937 B1 [0008]
• WO 1098041646 A1 [0009]
• - WO 2007009463 A2 [0009]

Cited non-patent literature

• - "Features of promising technologies for pre-treatment of lignocellulosic biomass" by Nathan Mosier and others, published in Bioresource Technology 96 (2005), page 673-686 [0005]
• - "Hydrolysis of lignocellulosic materials for ethanol production: a review", published in Bioresource Technologie 83 (2002), pages 1-11, Elsevier Verlag [0006]
• - http://www.ecn.nl/docs/library/report/2001/rx01011.pdf. [0033]

Claims (13)

Process for the processing of cereals and lignocellulose to bioethanol, characterized in that a production line for grain and at the same time operated production line lignocellulose operated until the saccharification stage and a specific fermentation depending on the biomass used and then passed the material streams in a common distillation and dewatering stage become. Method according to claim 1, characterized that on the production line for processing lignocellulose after a hydrolysis of the biomass excess Steam used in this production line elsewhere or for use in the production line for the grain is deducted. Method according to claim 1, characterized that after the hydrolysis stage in the production line for processing of lignocellulose a liquid phase largely from a solid phase separated and the liquid phase of a biogas plant is supplied. Method according to one of the preceding claims characterized in that the residues after distillation and drainage (stillage) fed to the biogas plant become. Method according to one of the preceding claims characterized in that in the biogas plant and Schlempe the hemicellulose rich liquid phase converted to biogas become. Method according to claim 5, characterized in that that the biogas is used to generate electricity. Method according to claim 1, characterized in that that the lignocellulose in the hydrolysis so open-minded is that the hydrolyzed mass a largely neutral pH, preferably in the range pH 5 to 7 by waiving Addition of acids or alkalis has. Method according to claim 1, characterized that the two simultaneously operated bioethanol plants with variable amounts of cereals and lignocellulosic Biomass, the proportion of lignocellulose, based on the amount of grain used, from 1 to a maximum of 50 Weight percent. Method according to one of the preceding claims characterized in that the final ethanol concentration is both in the processing of grain as well as in processing of lignocellulose prior to the distillation step, a final ethanol concentration of 4-19 volume percent. Device for processing the types of biomass cereals and lignocellulose to bioethanol, in particular to carry out the method according to any one of the preceding claims, wherein at least one of the devices comprising at least each an in-line pre-treatment, digestion, Saccharification, fermentation of saccharified masses for each Biomassenart be operated simultaneously or in parallel, characterized by only one common charge for both lines Distillation device and dewatering device for Concentration of the recovered ethanol. Device according to claim 10, characterized in that that both lines are coupled to a biogas plant for recording of stillage from the distillation equipment and from liquid phases one of the hydrolyzing device for lignocellulose downstream separating device for solids and liquids. Device according to claim 10 or 11, characterized that the hydrolysis part of the lignocellulose line with a discharge device connected by steam to the grain line. Apparatus according to claim 10, 11 or 12, characterized characterized in that the biogas plant with a power generation plant is coupled.