CA1282358C - Method of continuously recovering fermentation products - Google Patents
Method of continuously recovering fermentation productsInfo
- Publication number
- CA1282358C CA1282358C CA000496898A CA496898A CA1282358C CA 1282358 C CA1282358 C CA 1282358C CA 000496898 A CA000496898 A CA 000496898A CA 496898 A CA496898 A CA 496898A CA 1282358 C CA1282358 C CA 1282358C
- Authority
- CA
- Canada
- Prior art keywords
- fermentation
- mash
- slops
- distillery
- distillery slops
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
- C12P—FERMENTATION OR ENZYME-USING PROCESSES TO SYNTHESISE A DESIRED CHEMICAL COMPOUND OR COMPOSITION OR TO SEPARATE OPTICAL ISOMERS FROM A RACEMIC MIXTURE
- C12P7/00—Preparation of oxygen-containing organic compounds
- C12P7/02—Preparation of oxygen-containing organic compounds containing a hydroxy group
- C12P7/04—Preparation of oxygen-containing organic compounds containing a hydroxy group acyclic
- C12P7/06—Ethanol, i.e. non-beverage
-
- C—CHEMISTRY; METALLURGY
- C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
- C12F—RECOVERY OF BY-PRODUCTS OF FERMENTED SOLUTIONS; DENATURED ALCOHOL; PREPARATION THEREOF
- C12F3/00—Recovery of by-products
- C12F3/10—Recovery of by-products from distillery slops
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E50/00—Technologies for the production of fuel of non-fossil origin
- Y02E50/10—Biofuels, e.g. bio-diesel
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/50—Improvements relating to the production of bulk chemicals
- Y02P20/582—Recycling of unreacted starting or intermediate materials
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- Organic Chemistry (AREA)
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Life Sciences & Earth Sciences (AREA)
- Zoology (AREA)
- Wood Science & Technology (AREA)
- Bioinformatics & Cheminformatics (AREA)
- Health & Medical Sciences (AREA)
- Biochemistry (AREA)
- General Engineering & Computer Science (AREA)
- General Health & Medical Sciences (AREA)
- Genetics & Genomics (AREA)
- Microbiology (AREA)
- General Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Biotechnology (AREA)
- Preparation Of Compounds By Using Micro-Organisms (AREA)
- Apparatus Associated With Microorganisms And Enzymes (AREA)
- Vaporization, Distillation, Condensation, Sublimation, And Cold Traps (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE:
In a method of continuously recovering fermentation pro-ducts, such as ethanol, from a fermented mash, mash from a fermentation plant is supplied to a distilling unit, where it is separated into fermentation products and distillery slops. The distillery slops mainly freed from fermentation products are drawn off from the bottom part of the dis-tilling unit and partially returned to the fermentation plant. A further partial flow of distillery slops from the distilling unit is supplied to an indirectly heated evapo-rator stage for concentration therein, and the vapors formed there are fed directly into the lower region of the distilling unit, while the concentrated distillery slops formed in the evaporator stage are discharged.
In a method of continuously recovering fermentation pro-ducts, such as ethanol, from a fermented mash, mash from a fermentation plant is supplied to a distilling unit, where it is separated into fermentation products and distillery slops. The distillery slops mainly freed from fermentation products are drawn off from the bottom part of the dis-tilling unit and partially returned to the fermentation plant. A further partial flow of distillery slops from the distilling unit is supplied to an indirectly heated evapo-rator stage for concentration therein, and the vapors formed there are fed directly into the lower region of the distilling unit, while the concentrated distillery slops formed in the evaporator stage are discharged.
Description
~3235a The invention relates to a method of continuously re-covering fermentation products, in particular ethanol, from fermented mash, wherein the mash from a fermentation plant that possibly includes a raw material processing, possibly after separation and return of a microorganism culture into the fermentation plant - is supplied to a distilling unit, distillery 510ps to a large extent freed from fermentation products are drawn off from the bottom part of the di-stilling unit and partially returned into the raw material processing and fermentation stages.
U.S.patent No. 2,440,925 discloses a method of pro-ducing alcohol, in which mash present in a fermentation vessel is fermented with yeast, a part of the fermented mash liquid is continuously drawn off, distilled under a reduced pressure, and the distillery slops freed from alco-hol are returned to the fermentation vessel so as to keep low the alcohol content of the mash and thus not damage the yeast. However, from time to time the production process must be interrupted in order to let off mash enriched with unusable substances from the fermentation vessel.
In zymotechnological plants the disposal of the dis-tillery slops constitutes a problem of increasing impor-tance. At present, one of the most common methods is the concentration of the distillery slops and their use as fodder or as fuel - e.g., for the production of vapor.
For reducing the amounts of distillery slops incurring and for decreasing the amount of process water required for diluting the mash, lt is known to recycle alcoholic mash liquid having varying contents of ethanol or distillery slops from the distillation to the raw material processi.ng and/or to fermentation. The raw material processing may, e.g., consist in hydrolyzing and saccharifying starch. Also a possible separation and outward transfer of suspended solids with the help of separating devices such as screen bends, sedimentation vessels and centrifuges, as well as the separation oE yeast from alcoholic mash and return of yeast into the fermentation stage are known.
Thus, European Patent No. 0 011 334 relates to a pro-cess for the continuous production of ethanol, wherein a partial stream of the fermented mash is continuously re-moved, the yeast cells are separated from the mash by means of a centrifuge and are returned into the fermentation and the mash is returned to the fermentation after a complete or partial removal of the alcohol in a vacuum evaporator.
According to Canadian patent No. 1,110,986, a flow from the fermentation is separated by centrifugation into a yeast concentrate and yeast-free flow, the yeast concentrate is returned to fermentation, and the yeast-free flow is distilled. The residual flow having a low ethanol content resulting from the distillation is partially returned to fermentation as a substrate flow freed from solids after having been ut1lized for the preparation of a raw material flow.
Also according to Canadian patent No. 1,147,678 a yeast concentrate is separated from the fermentation liquid and returned to fermentation; the ethanol-containing liquid that is free from yeast is first fed into a simple evapora-tor and, there, is separated into a vapor flow rich in 0 ethanol and a bottom flow. The larger portion of the liquid ' 35~3 bottom flow is returned to fermentation, and the residual portion is supp]ied to a stripping unit, from which the top product rich in ethanol gets into a distilling unit to-gether with the vapor flow from the evaporator rich in ethanol.
From Canadian patent No. 1,140,872 it is known, for the production of ethanol by fermentation of a carbohy-drate-containing substrate, to first supply the fermenta-tion broth to a simple vacuum evaporator, to return the liquid yeast-containing bottom flow from the evaporator partially to the fermentation, and to separate the remain-der into a yeast concentrate flow that is also returned to the fermentation, as well as into a flow free from yeast which is supplied to a stripping unit. The vapor flow rich in ethanol from the vaccum evaporator is further worked up in a rectifying column, the vapor flow rich in ethanol from the stripping unit may be supplied to the evaporator.
Finally, Canadian Patent No. 1,138,798 deals with a method of a similar kind with integrated raw material processing, in which the fermenting broth is separated into a returned yeast concentrate flow and a flow free from yeast, at least a part of the flow free from yeast is separated in a simple evaporator into a vapor flow rich in ethanol and a liquid bottom flow, the latter is at least partially again returned to fermentation and the vapor flow rich in ethanol is guided to a fractionation unit. The polysaccharide-containing raw material is - preferably pre-hydrolyzed - introduced into the evaporator and there en-zymatically further hydrolyzed. With the liquid bottom flow the dis30 integrated raw materials get to the fermen-32;358 tation, wherein also enzymes may be added to the fermentor.
If, according to the known methods, only partly de-alcolholized mash is recycled, due to the amount of alcohol ie~ in circulation there results a corresponding increase in the liquid volumes in the fermentation and in possible separating devices. However, larger dimensioned apparatuses cause higher investment costs and consume more energy when operated.
If, however, mash de-alcoholized as far as possible (distillery slops) is recycled which has the same content of dry substances as the distillery slops to be derived from the process, relatively large amounts of distillery slops will still be incurred, since the amount of distill-ery slops capable of being recycled in most substrates is limited by a maximum dry substance concentration in the fermentation plant. Despite this, in each case it is more favorable for reasons of process technology to provide as low a portion of unfermentable dry substance as possible in the mash to be fermented.
The invention aims at overcoming the disadvantages and difficulties still connected with the known methods and to provide an energy-saving method requiring simple apparatus, with which distillery slops of a higher concentration are incurred in a reduced amount and the amount of process water required comparatively may be kept very low without having to put up with a substantial inhibition of the course of fermentation due to a too pronounced enrichment of fermenta~ion products or unusable substances.
'. :
3~8 Thus the present invention provides a method of continuously recovering fermentation products, such as ethanol, from a fermented mash, including supplying the mash from a fermentation plant to a distilling unit having a lower region and a bottom part, distilling the mash in the distilling unit thereby separating the mash into fermentation products and distillery slops, drawing off the distlllery slops largely freed from fermentation products from the bottom part of the distilling unit, partlally returning the distillery slops into the fermen~ation plant, forming a further partial flow of the distillery slops drawn off from the distilling unit, supplying the further partial flow of distillery slops to an indirectly heated evaporator stage so as to concentrate the distillery slops therein and form vapors, feeding the vapors formed in the evaporator stage directly into the lower region of the distilling unit and discharging the concentrated distillery slops formed in the evaporator stage.
The invention further relates to a method of continuously recovering fermentation products from a fermented mash, comprising the steps of supplying the mash from a processing ~0 unit including a fermentation plant and a raw material processing plant to a distilling unit having a lo~er region and a bottom part, distilling the mash in the distilling unit thereby separating the mash into fermentation products and distillery slops, the distillery slops having substances suspended therein, drawing off the distillery slops largely freed from fermentation products from the bottom part of the distilling unit, separating and discharging the substances suspended in the distillery slops, '~
' . ~ ' ' .
lX~323~
partially returning the distlllery slops freecl from the suspended substances into the fermentation plant, separating a micro-organism culture from the mash coming from the fermentation plant and returning ~he micro-oryanism culture into the fermentation plant prior to supplying the mash to the distilling unit, and forming a further partial flow of the distillery slops drawn off from the distilling unit, supplying the further partial flow o~
dlstillery slops to an indirectly heated evaporator stage so as to concentrate the distillery slops therein and form vapors, feeding the vapors formed in the evaporator stage directly into the lower region of the distilling unit and discharginy the concentrated distillery slops formed in the evaporated stage, the distillery slops largely freed from fermentakion products and drawn off from the bottom part of the distilling unit being partially returned to at least one of the raw materlal processing plant and the fermentation plant.
The single figure of the drawings accompanying the speciflcation is a schematic view of a fermentation plant suitable for carrying out the process of the invention.
Beside ethanol, also other distillable fermentation products, such as butanol and acetone, may be obtained as the top products of a distilling unit. Bu~anol and possibly acetone are formed in the anaerobic fermentation wlth, e.g., Clostridium butylicum or acetobutylicum ~rom glucose-containing substrates.
For ethanolic fermenta~ion yeasts are commonly 5a .~
' .~
.
: ' .
~' ~X8~3~8 - 5~ - 242~2-410 used as micro-organisms.
The separation of the micro-organism culture from the fermented mash may already take place prior to feeding the fermentation-product-containing mash into the distilling unit -e.g., by centrifugation. If the pressure is not sufficient while working in the distilling unit, so that temperatures of more -than approximately 40C are reached during distillation, which temperatures are already detrimental to the micro-organisms, it is of course preferable in many cases that the micro-organisms are separated beforehand.
According to a preferred embodiment of the method according to the invention, substances suspended in the drawn off distillery slops are separated. Only the distillery slops freed from suspended solids are divided, partially returned into the raw material processing and/or the fermentation stages, and a different partial flow is led into -the evaporator stage.
The invention further provides a method of continuously recovering fermentation products, such as ethanol, from a ermented mash, including supplying said mash from a fermentation plant to a distilling unit having a lower region and a bottom part, distilling said mash in said distilling unit thereby separating said mash into fermentation products and distlllery slops, drawing off said distillery slops largely freed from fermentation products from the bottom part of said d~isti]ling unit, partially returning said distillery slops into said fermentation plan~t, comprising separating a micro-organism ~,~,..
, - ~ .
~X~3~3S8 ` ( ,, - 5~ - 24242-410 culture from said mash coming from said fermentation plant and returning said micro-organism culture into said fermentation plant prior to supplying said mash to said distilling unit, and forming a further parti.al flow of said distillery slops drawn off from said distilling unit, supplying said further partial flow of distillery slops to an indirectly heated evaporator stage so as to concentrate said distillery slops therein and form vapors, feeding said vapors formed in said evaporator stage directly into the lower region of said distilling unit and discharging said concentrated distillery slops formed in said evaporated stage, said fermentation plant further including a raw material processing plant wherein said distillery slops largely freed from fermentation products and drawn off from said bottom part of said distilling unit are partially returned to at least one of said raw material processing plant and said fermentation plant.
:
: : :
,, ' ~` ~ , ` . ' ' .
3~13 In case of a distilling unit operated under a suffi-cient vacuum, the micro-organism culture may also be sepa-rated from the drawn-off distillery slops - e.g., by means of centrifugal separators - and may again be added to the fermentation stage.
If the distilling unit is opera-ted under a slight vacuum only, under normal or overpressure, suitably the thermal content of the distillery slops drawn off from the distillation unit is partly transferred to the mash sup-plied to the distilling unit via one or more heat exchan-gers. The heat transfer to the mash coming from the fermen-tation plant in this case is particularly effected before the separation of suspended substances from the distillery slops, i.e., immediately after the drawing off of the distillery slops from the distilling unit (separating column) so as to avoid disturbances connected with the boiling behavior of the distillery slops - e.g~, during a separation by decantation - as well as thermal losses during a possible intermediate storing. For an even better utilization of the energy, it is of additional advantage also to pre-heat the partial flow of the distillery slops freed from suspended substances and to be led into the evaporator stage, by means of the total amount of the distillery slops immediately drawn off from the distilling unit, a part of the thermal content of the distillery slops still containing suspended substances at first being transferred to this partial flow and subse~uently to the mash supplied to the distilling unit.
If a sufficiently low pressure is adjusted in the 0 distilling unit, a cooling of the total amount of the drawn ~ ~X358 off distillery slops is not necessary, and preferably only that part of the distillery slops returned to the raw material processing and/or to the fermentation stages is used for pre-heating the mash. The pre-heating of the mash may additionally or exclusively be also carried out with any other media incurred in the plant.
A preferred embodiment of the invention will be ex-plained in the following in more detail by way of a process diagram.
An aqueous raw material flow 1 with vegetable, sugar, starch and cellulose containing starting material, such as cereals, sugar cane or molasses, at first reaches a pro-cessing means 2, in which the raw materials are disinte-grated, hydrolyzed, and, if necessary, purified. The sub-strate obtained or mash 3 is guided into the fermentation stage 4, where the fermentation takes place under the action of micro-organisms.
A certain fraction of the fermented mash is contin-uously drawn off and guided through duct 5 into a centri-fugal separator 6. The separated micro-organism culture is returned into the fermentation stage 4 vla duct 7, and the fermentation-product-containing mash is pumped through a regenerative heat exchanger 8 into the upper section of a distilling unit 9. Su1tably, the distilling unit in most cases comprises a single separating column from whose top a vapor flow enriched with fermentation products is withdrawn through duct 10, e.g. in order to be led to a rectifica-tion.
If, e.g., very large amounts of fermented mash must be 0 worked up, the distilling unit may also consist of two or ~a~3~
more distilling columns. The distillery slops that to a large extent are freed from fermentation products are led from the bottom part of the distilling unit 9 into a means for separating suspended substances. In the embodiment illustrated, a screen bend 11 is provided for the sepaxa-tion.
The separated solids are withdrawn from the process as indicated by arrow 12. A portion of the distillery slops freed to a large extent from suspended substances by means of the screen bend 11 is returned into the raw material preparation means 2 and/or into the fermentation stage 4 via duct 13 while giving off heat in the heat exchanger 8 to the fermentation-product-containing mash. A further partial flow of the distillery slops is led through duct branch 14 into an indirectly heated evaporator stage 15.
The evaporator stage comprising one or more simple evaporators each having one or only a few theoretical separation stage(s) may, e.g., be heated with fresh vapor or by heat exchange with any hot medium available in the plant. The temperatures to be adjusted mainly depend on the pressure conditions prevailing in the individual parts of the plant. The vapors forming in the evaporator stage 15 and mainly consisting of water vapor, are supplied via~
supply duct 16 into the lower region of the distilling unit 9 for directly heating the same.
Due to the delivery of vapors, the distillery slops finally leaving the evaporator stage 15 through discharge 17 are very concentrated as compar,ed to that part of the distillery slops returned into the raw material processing and fermentation stages through duct 13. The concentrated ~: :. . .
8Z35~3 distillery slops from discharge 17 may in some instances be used as fodder without further removal of water or, since they are autothermic due to their high content of dry substances, they may be burned directly.
With the method according to the invention, thus non-fermentable substances as well as fermentation products that are toxic for the micro-organisms in higher concen-trations are continuously removed from the process in a particularly energy-saving manner, and furthermore the amount of distillery slops incurred is drastically reduced.
In the following table the advantages of the method according to the invention are demonstrated by the example of the ethanolic fermentation by comparing the material flows of two known methods and of the method according to the invention.
I relates to a known method in which the distilling unit in the bottom part is indirectly heated, partly de-alcoholized mash is returned into the raw material pro-cessing and fermentation stages and distillery slops are drawn off from the sump of the distilling unit.
II symbolizes a known method in which the heating of the distilling unit is effected as in method I, yet largely de-alcoholized mash tdistillery slops) from the sump of the distilling unit is partly recycled.
III denotes the method according to the invention.
The composition of the fermented mash fed Erom the fermentation plant was the same in all three cases. As basis of reference the recovery of 100 kg of pure ethanol/h was chosen, the ethanol content of the crude spirit drawn off from th_ top of the distilling unit each being 40 % by ~8;~3~8 mass.
As can be seen from the table, with the method of the invention (III) the total amount of fermented mash to be processed is lower by about 11 % as compared to method I.
The total amount of distillery slops of the method of the invention is reduced by about 30 ~ - as compared to method II - with a simultaneously higher content of dry substance.
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U.S.patent No. 2,440,925 discloses a method of pro-ducing alcohol, in which mash present in a fermentation vessel is fermented with yeast, a part of the fermented mash liquid is continuously drawn off, distilled under a reduced pressure, and the distillery slops freed from alco-hol are returned to the fermentation vessel so as to keep low the alcohol content of the mash and thus not damage the yeast. However, from time to time the production process must be interrupted in order to let off mash enriched with unusable substances from the fermentation vessel.
In zymotechnological plants the disposal of the dis-tillery slops constitutes a problem of increasing impor-tance. At present, one of the most common methods is the concentration of the distillery slops and their use as fodder or as fuel - e.g., for the production of vapor.
For reducing the amounts of distillery slops incurring and for decreasing the amount of process water required for diluting the mash, lt is known to recycle alcoholic mash liquid having varying contents of ethanol or distillery slops from the distillation to the raw material processi.ng and/or to fermentation. The raw material processing may, e.g., consist in hydrolyzing and saccharifying starch. Also a possible separation and outward transfer of suspended solids with the help of separating devices such as screen bends, sedimentation vessels and centrifuges, as well as the separation oE yeast from alcoholic mash and return of yeast into the fermentation stage are known.
Thus, European Patent No. 0 011 334 relates to a pro-cess for the continuous production of ethanol, wherein a partial stream of the fermented mash is continuously re-moved, the yeast cells are separated from the mash by means of a centrifuge and are returned into the fermentation and the mash is returned to the fermentation after a complete or partial removal of the alcohol in a vacuum evaporator.
According to Canadian patent No. 1,110,986, a flow from the fermentation is separated by centrifugation into a yeast concentrate and yeast-free flow, the yeast concentrate is returned to fermentation, and the yeast-free flow is distilled. The residual flow having a low ethanol content resulting from the distillation is partially returned to fermentation as a substrate flow freed from solids after having been ut1lized for the preparation of a raw material flow.
Also according to Canadian patent No. 1,147,678 a yeast concentrate is separated from the fermentation liquid and returned to fermentation; the ethanol-containing liquid that is free from yeast is first fed into a simple evapora-tor and, there, is separated into a vapor flow rich in 0 ethanol and a bottom flow. The larger portion of the liquid ' 35~3 bottom flow is returned to fermentation, and the residual portion is supp]ied to a stripping unit, from which the top product rich in ethanol gets into a distilling unit to-gether with the vapor flow from the evaporator rich in ethanol.
From Canadian patent No. 1,140,872 it is known, for the production of ethanol by fermentation of a carbohy-drate-containing substrate, to first supply the fermenta-tion broth to a simple vacuum evaporator, to return the liquid yeast-containing bottom flow from the evaporator partially to the fermentation, and to separate the remain-der into a yeast concentrate flow that is also returned to the fermentation, as well as into a flow free from yeast which is supplied to a stripping unit. The vapor flow rich in ethanol from the vaccum evaporator is further worked up in a rectifying column, the vapor flow rich in ethanol from the stripping unit may be supplied to the evaporator.
Finally, Canadian Patent No. 1,138,798 deals with a method of a similar kind with integrated raw material processing, in which the fermenting broth is separated into a returned yeast concentrate flow and a flow free from yeast, at least a part of the flow free from yeast is separated in a simple evaporator into a vapor flow rich in ethanol and a liquid bottom flow, the latter is at least partially again returned to fermentation and the vapor flow rich in ethanol is guided to a fractionation unit. The polysaccharide-containing raw material is - preferably pre-hydrolyzed - introduced into the evaporator and there en-zymatically further hydrolyzed. With the liquid bottom flow the dis30 integrated raw materials get to the fermen-32;358 tation, wherein also enzymes may be added to the fermentor.
If, according to the known methods, only partly de-alcolholized mash is recycled, due to the amount of alcohol ie~ in circulation there results a corresponding increase in the liquid volumes in the fermentation and in possible separating devices. However, larger dimensioned apparatuses cause higher investment costs and consume more energy when operated.
If, however, mash de-alcoholized as far as possible (distillery slops) is recycled which has the same content of dry substances as the distillery slops to be derived from the process, relatively large amounts of distillery slops will still be incurred, since the amount of distill-ery slops capable of being recycled in most substrates is limited by a maximum dry substance concentration in the fermentation plant. Despite this, in each case it is more favorable for reasons of process technology to provide as low a portion of unfermentable dry substance as possible in the mash to be fermented.
The invention aims at overcoming the disadvantages and difficulties still connected with the known methods and to provide an energy-saving method requiring simple apparatus, with which distillery slops of a higher concentration are incurred in a reduced amount and the amount of process water required comparatively may be kept very low without having to put up with a substantial inhibition of the course of fermentation due to a too pronounced enrichment of fermenta~ion products or unusable substances.
'. :
3~8 Thus the present invention provides a method of continuously recovering fermentation products, such as ethanol, from a fermented mash, including supplying the mash from a fermentation plant to a distilling unit having a lower region and a bottom part, distilling the mash in the distilling unit thereby separating the mash into fermentation products and distillery slops, drawing off the distlllery slops largely freed from fermentation products from the bottom part of the distilling unit, partlally returning the distillery slops into the fermen~ation plant, forming a further partial flow of the distillery slops drawn off from the distilling unit, supplying the further partial flow of distillery slops to an indirectly heated evaporator stage so as to concentrate the distillery slops therein and form vapors, feeding the vapors formed in the evaporator stage directly into the lower region of the distilling unit and discharging the concentrated distillery slops formed in the evaporator stage.
The invention further relates to a method of continuously recovering fermentation products from a fermented mash, comprising the steps of supplying the mash from a processing ~0 unit including a fermentation plant and a raw material processing plant to a distilling unit having a lo~er region and a bottom part, distilling the mash in the distilling unit thereby separating the mash into fermentation products and distillery slops, the distillery slops having substances suspended therein, drawing off the distillery slops largely freed from fermentation products from the bottom part of the distilling unit, separating and discharging the substances suspended in the distillery slops, '~
' . ~ ' ' .
lX~323~
partially returning the distlllery slops freecl from the suspended substances into the fermentation plant, separating a micro-organism culture from the mash coming from the fermentation plant and returning ~he micro-oryanism culture into the fermentation plant prior to supplying the mash to the distilling unit, and forming a further partial flow of the distillery slops drawn off from the distilling unit, supplying the further partial flow o~
dlstillery slops to an indirectly heated evaporator stage so as to concentrate the distillery slops therein and form vapors, feeding the vapors formed in the evaporator stage directly into the lower region of the distilling unit and discharginy the concentrated distillery slops formed in the evaporated stage, the distillery slops largely freed from fermentakion products and drawn off from the bottom part of the distilling unit being partially returned to at least one of the raw materlal processing plant and the fermentation plant.
The single figure of the drawings accompanying the speciflcation is a schematic view of a fermentation plant suitable for carrying out the process of the invention.
Beside ethanol, also other distillable fermentation products, such as butanol and acetone, may be obtained as the top products of a distilling unit. Bu~anol and possibly acetone are formed in the anaerobic fermentation wlth, e.g., Clostridium butylicum or acetobutylicum ~rom glucose-containing substrates.
For ethanolic fermenta~ion yeasts are commonly 5a .~
' .~
.
: ' .
~' ~X8~3~8 - 5~ - 242~2-410 used as micro-organisms.
The separation of the micro-organism culture from the fermented mash may already take place prior to feeding the fermentation-product-containing mash into the distilling unit -e.g., by centrifugation. If the pressure is not sufficient while working in the distilling unit, so that temperatures of more -than approximately 40C are reached during distillation, which temperatures are already detrimental to the micro-organisms, it is of course preferable in many cases that the micro-organisms are separated beforehand.
According to a preferred embodiment of the method according to the invention, substances suspended in the drawn off distillery slops are separated. Only the distillery slops freed from suspended solids are divided, partially returned into the raw material processing and/or the fermentation stages, and a different partial flow is led into -the evaporator stage.
The invention further provides a method of continuously recovering fermentation products, such as ethanol, from a ermented mash, including supplying said mash from a fermentation plant to a distilling unit having a lower region and a bottom part, distilling said mash in said distilling unit thereby separating said mash into fermentation products and distlllery slops, drawing off said distillery slops largely freed from fermentation products from the bottom part of said d~isti]ling unit, partially returning said distillery slops into said fermentation plan~t, comprising separating a micro-organism ~,~,..
, - ~ .
~X~3~3S8 ` ( ,, - 5~ - 24242-410 culture from said mash coming from said fermentation plant and returning said micro-organism culture into said fermentation plant prior to supplying said mash to said distilling unit, and forming a further parti.al flow of said distillery slops drawn off from said distilling unit, supplying said further partial flow of distillery slops to an indirectly heated evaporator stage so as to concentrate said distillery slops therein and form vapors, feeding said vapors formed in said evaporator stage directly into the lower region of said distilling unit and discharging said concentrated distillery slops formed in said evaporated stage, said fermentation plant further including a raw material processing plant wherein said distillery slops largely freed from fermentation products and drawn off from said bottom part of said distilling unit are partially returned to at least one of said raw material processing plant and said fermentation plant.
:
: : :
,, ' ~` ~ , ` . ' ' .
3~13 In case of a distilling unit operated under a suffi-cient vacuum, the micro-organism culture may also be sepa-rated from the drawn-off distillery slops - e.g., by means of centrifugal separators - and may again be added to the fermentation stage.
If the distilling unit is opera-ted under a slight vacuum only, under normal or overpressure, suitably the thermal content of the distillery slops drawn off from the distillation unit is partly transferred to the mash sup-plied to the distilling unit via one or more heat exchan-gers. The heat transfer to the mash coming from the fermen-tation plant in this case is particularly effected before the separation of suspended substances from the distillery slops, i.e., immediately after the drawing off of the distillery slops from the distilling unit (separating column) so as to avoid disturbances connected with the boiling behavior of the distillery slops - e.g~, during a separation by decantation - as well as thermal losses during a possible intermediate storing. For an even better utilization of the energy, it is of additional advantage also to pre-heat the partial flow of the distillery slops freed from suspended substances and to be led into the evaporator stage, by means of the total amount of the distillery slops immediately drawn off from the distilling unit, a part of the thermal content of the distillery slops still containing suspended substances at first being transferred to this partial flow and subse~uently to the mash supplied to the distilling unit.
If a sufficiently low pressure is adjusted in the 0 distilling unit, a cooling of the total amount of the drawn ~ ~X358 off distillery slops is not necessary, and preferably only that part of the distillery slops returned to the raw material processing and/or to the fermentation stages is used for pre-heating the mash. The pre-heating of the mash may additionally or exclusively be also carried out with any other media incurred in the plant.
A preferred embodiment of the invention will be ex-plained in the following in more detail by way of a process diagram.
An aqueous raw material flow 1 with vegetable, sugar, starch and cellulose containing starting material, such as cereals, sugar cane or molasses, at first reaches a pro-cessing means 2, in which the raw materials are disinte-grated, hydrolyzed, and, if necessary, purified. The sub-strate obtained or mash 3 is guided into the fermentation stage 4, where the fermentation takes place under the action of micro-organisms.
A certain fraction of the fermented mash is contin-uously drawn off and guided through duct 5 into a centri-fugal separator 6. The separated micro-organism culture is returned into the fermentation stage 4 vla duct 7, and the fermentation-product-containing mash is pumped through a regenerative heat exchanger 8 into the upper section of a distilling unit 9. Su1tably, the distilling unit in most cases comprises a single separating column from whose top a vapor flow enriched with fermentation products is withdrawn through duct 10, e.g. in order to be led to a rectifica-tion.
If, e.g., very large amounts of fermented mash must be 0 worked up, the distilling unit may also consist of two or ~a~3~
more distilling columns. The distillery slops that to a large extent are freed from fermentation products are led from the bottom part of the distilling unit 9 into a means for separating suspended substances. In the embodiment illustrated, a screen bend 11 is provided for the sepaxa-tion.
The separated solids are withdrawn from the process as indicated by arrow 12. A portion of the distillery slops freed to a large extent from suspended substances by means of the screen bend 11 is returned into the raw material preparation means 2 and/or into the fermentation stage 4 via duct 13 while giving off heat in the heat exchanger 8 to the fermentation-product-containing mash. A further partial flow of the distillery slops is led through duct branch 14 into an indirectly heated evaporator stage 15.
The evaporator stage comprising one or more simple evaporators each having one or only a few theoretical separation stage(s) may, e.g., be heated with fresh vapor or by heat exchange with any hot medium available in the plant. The temperatures to be adjusted mainly depend on the pressure conditions prevailing in the individual parts of the plant. The vapors forming in the evaporator stage 15 and mainly consisting of water vapor, are supplied via~
supply duct 16 into the lower region of the distilling unit 9 for directly heating the same.
Due to the delivery of vapors, the distillery slops finally leaving the evaporator stage 15 through discharge 17 are very concentrated as compar,ed to that part of the distillery slops returned into the raw material processing and fermentation stages through duct 13. The concentrated ~: :. . .
8Z35~3 distillery slops from discharge 17 may in some instances be used as fodder without further removal of water or, since they are autothermic due to their high content of dry substances, they may be burned directly.
With the method according to the invention, thus non-fermentable substances as well as fermentation products that are toxic for the micro-organisms in higher concen-trations are continuously removed from the process in a particularly energy-saving manner, and furthermore the amount of distillery slops incurred is drastically reduced.
In the following table the advantages of the method according to the invention are demonstrated by the example of the ethanolic fermentation by comparing the material flows of two known methods and of the method according to the invention.
I relates to a known method in which the distilling unit in the bottom part is indirectly heated, partly de-alcoholized mash is returned into the raw material pro-cessing and fermentation stages and distillery slops are drawn off from the sump of the distilling unit.
II symbolizes a known method in which the heating of the distilling unit is effected as in method I, yet largely de-alcoholized mash tdistillery slops) from the sump of the distilling unit is partly recycled.
III denotes the method according to the invention.
The composition of the fermented mash fed Erom the fermentation plant was the same in all three cases. As basis of reference the recovery of 100 kg of pure ethanol/h was chosen, the ethanol content of the crude spirit drawn off from th_ top of the distilling unit each being 40 % by ~8;~3~8 mass.
As can be seen from the table, with the method of the invention (III) the total amount of fermented mash to be processed is lower by about 11 % as compared to method I.
The total amount of distillery slops of the method of the invention is reduced by about 30 ~ - as compared to method II - with a simultaneously higher content of dry substance.
- I O -:
~.Z~3~35~3 ~ __ . _ _ H ~ N ~ 111 H ~ +l ~ 4~ a~
H I +0~ ~j ~I O ~1 ~ HH ~ ~ ~ r r rl H I O O CO ~D Ir~
1~ H ~ +1 ~1 ~ . CO
~D O ~1 O ~ H ¦ O O O O O
H j . N .. ..
. ~ ~ H O O O O O
~1 ~
o H ~ O ~
I .. _____. __ _ I~ __ H i O N ~D
D H O N ~O
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~ ~'~ ~ ~
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~ L~ ~'~ ~ .
. ' . .
Claims (3)
1. A method of continuously recovering fermentation products from a fermented mash, comprising the steps of supplying said mash from a processing unit including a fermentation plant and a raw material processing plant to a distilling unit having a lower region and a bottom part, distilling said mash in said distilling unit thereby separating said mash into fermentation products and distillery slops, said distillery slops having substances suspended therein, drawing off said distillery slops largely freed from fermentation products from the bottom part of said distilling unit, separating and discharging the substances suspended in said distillery slops, partially returning said distillery slops freed from the suspended substances into said fermentation plant, separating a micro-organism culture from said mash coming from said fermentation plant and returning said micro-organism culture into said fermentation plant prior to supplying said mash to said distilling unit, and forming a further partial flow of said distillery slops drawn off from said distilling unit, supplying said further partial flow of distillery slops to an indirectly heated evaporator stage so as to concentrate said distillery slops therein and form vapors, feeding said vapors formed in said evaporator stage directly into the lower region of said distilling unit and discharging said concentrated distillery slops formed in said evaporated stage, said distillery slops largely freed from fermentation products and drawn off from said bottom part of said distilling unit being partially returned to at least one of said raw material processing plant and said fermentation plant.
2. A method as set forth in claim 1, wherein the fermentation product recovered is ethanol.
3. A method as set forth in claim 1, further comprising partially transferring in at least one heat exchanger the thermal content of the distillery slops drawn off from said distilling unit onto the mash supplied to the distilling unit.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AT0395284A AT384236B (en) | 1984-12-13 | 1984-12-13 | METHOD FOR CONTINUOUSLY WINNING FERMENTATION PRODUCTS |
| ATA3952/84 | 1984-12-13 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1282358C true CA1282358C (en) | 1991-04-02 |
Family
ID=3557650
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000496898A Expired - Lifetime CA1282358C (en) | 1984-12-13 | 1985-12-05 | Method of continuously recovering fermentation products |
Country Status (5)
| Country | Link |
|---|---|
| EP (1) | EP0185010B1 (en) |
| AT (1) | AT384236B (en) |
| BR (1) | BR8506240A (en) |
| CA (1) | CA1282358C (en) |
| DE (1) | DE3569750D1 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7297236B1 (en) | 2001-06-30 | 2007-11-20 | Icm, Inc. | Ethanol distillation process |
| AU2006251123B2 (en) * | 2005-05-25 | 2010-07-29 | St1 Biofuels Oy | Method and apparatus for preparing an ethanol/water mixture |
| CN106083526A (en) * | 2016-06-01 | 2016-11-09 | 金河生物科技股份有限公司 | Ethanol reclaims the system and method for Automated condtrol |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AT395983B (en) * | 1986-03-10 | 1993-04-26 | Vogelbusch Gmbh | METHOD FOR PRODUCING AETHANOL FROM SUGAR-CONTAINING RAW MATERIALS, AND SYSTEM FOR IMPLEMENTING THE METHOD |
| DE3704407A1 (en) * | 1987-01-15 | 1988-07-28 | Gea Wiegand Gmbh | System for removing an alcohol/water mixture from alcohol-containing mash |
| DE102006049174A1 (en) * | 2006-10-18 | 2008-04-30 | Gea Wiegand Gmbh | Plant for separating ethanol from fermented mash |
| FI20075288A0 (en) * | 2007-04-25 | 2007-04-25 | St1 Biofuels Oy | Method and apparatus for preparing a mixture of ethanol and water |
| DE102007055503A1 (en) * | 2007-11-21 | 2009-05-28 | Bayer Technology Services Gmbh | Preparation of alcohols from biomass using in situ distillation |
| DE102009050516A1 (en) * | 2009-10-23 | 2011-05-19 | S4 Invest Gmbh & Co. Kg | Method for batchwise preparation of alcohol from biomass comprises saccharization of carbohydrate to sugar by enzyme, fermentation of sugar to alcohol by yeast, distillation of alcohol and separation of solid phase from liquid phase |
| CN108485893A (en) * | 2018-05-31 | 2018-09-04 | 平南县科力酿酒机械制造有限公司 | Continuous liquor steaming device and its continuous liquor steaming method |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1109311A (en) * | 1963-08-07 | 1968-04-10 | Hiram Walker & Sons Scotland L | Improvements in or relating to the production of grain whisky |
| SE432441B (en) * | 1979-02-27 | 1984-04-02 | Alfa Laval Ab | PROCEDURE FOR PREPARING ETHANOL BY CONTINUOUS SPRAYING OF A CARBOHYDRATE-SUBSTRATE, WHICH A DRINK WITH RELATIVE HIGH RATE OF SOLID SUBSTANCE RECOVERY |
| NL8005147A (en) * | 1980-09-12 | 1982-04-01 | Hollandse Const Groep | METHOD AND APPARATUS FOR PROCESSING VINASSE |
| DE3204910A1 (en) * | 1981-05-12 | 1982-12-02 | Peter 2724 Ahausen Rothe | Process and device for alcohol production |
| DE3130814A1 (en) * | 1981-08-04 | 1983-02-17 | Metallgesellschaft Ag, 6000 Frankfurt | METHOD FOR CONCENTRATING SLURCHES |
| SE430699B (en) * | 1981-11-06 | 1983-12-05 | Alfa Laval Ab | PROCEDURE FOR PREPARING ETHANOL BY CONTINUOUS SPRAYING OF A CARBOHYDRATE-SUBSTRATE, WHEREAS THE FERMENTOR IS ADDED TO A RAVARA WHICH EXCEPT JESBARA CARBOHYDRATES, INCLUDES NOT JESBIAL |
-
1984
- 1984-12-13 AT AT0395284A patent/AT384236B/en not_active IP Right Cessation
-
1985
- 1985-12-05 DE DE8585890302T patent/DE3569750D1/en not_active Expired
- 1985-12-05 EP EP85890302A patent/EP0185010B1/en not_active Expired
- 1985-12-05 CA CA000496898A patent/CA1282358C/en not_active Expired - Lifetime
- 1985-12-12 BR BR8506240A patent/BR8506240A/en unknown
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7297236B1 (en) | 2001-06-30 | 2007-11-20 | Icm, Inc. | Ethanol distillation process |
| US7572353B1 (en) | 2001-06-30 | 2009-08-11 | Icm, Inc. | Ethanol distillation process |
| AU2006251123B2 (en) * | 2005-05-25 | 2010-07-29 | St1 Biofuels Oy | Method and apparatus for preparing an ethanol/water mixture |
| CN106083526A (en) * | 2016-06-01 | 2016-11-09 | 金河生物科技股份有限公司 | Ethanol reclaims the system and method for Automated condtrol |
| CN106083526B (en) * | 2016-06-01 | 2018-06-19 | 金河生物科技股份有限公司 | Ethyl alcohol recycles the system and method for automation control |
Also Published As
| Publication number | Publication date |
|---|---|
| ATA395284A (en) | 1987-03-15 |
| EP0185010B1 (en) | 1989-04-26 |
| DE3569750D1 (en) | 1989-06-01 |
| AT384236B (en) | 1987-10-12 |
| EP0185010A1 (en) | 1986-06-18 |
| BR8506240A (en) | 1986-08-26 |
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