Method and apparatus for dealcoholization

Abstract

A process for dealcoholizing a starting liquid (F) containing water and alcohol, in particular ethanol, as well as flavorings and / or nutrients, by means of a first membrane separation unit (1), in particular a diafiltration unit (10), comprising at least one separation membrane (12), wherein the starting liquid (F) is introduced under overpressure into a primary-side chamber (13) of the first membrane separation unit (1), in the secondary-side chamber (14) of which downstream of the at least one separation membrane (12) a lower pressure prevails than in the primary-side chamber (13), wherein water and alcohol pass through the at least one separation membrane (12) into the secondary-side chamber (14) as an alcohol-containing liquid permeate (P1), wherein water or a water-containing liquid is added directly or indirectly as a diluent (V) to a retentate (R1) retained by the at least one separation membrane (12) in the primary-side chamber (13).The system is characterized by the fact that the alcohol-containing liquid permeate (P1) is post-treated in a pervaporation unit (20) of a second membrane separation unit (2), wherein the alcohol-containing liquid permeate (P1) is first introduced into a primary-side chamber (23) of the pervaporation unit (20), where the alcohol evaporates in at least one pervaporation membrane (22) and enters as alcohol-containing gaseous permeate (P2) into a secondary-side chamber (26) of the pervaporation unit (20) downstream of the at least one pervaporation membrane (22), and wherein the water of the alcohol-containing liquid permeate (P1) is retained as retentate (R2) in the primary-side chamber (23) of the pervaporation unit (20) and reused.

Description

[0001] The present invention relates to a method for dealcoholizing a starting liquid containing water and alcohol as well as flavorings and / or nutrients by means of a membrane separation unit according to claim 1. It further relates to a device for dealcoholizing a starting liquid containing water and alcohol as well as flavorings and / or nutrients, which is particularly designed for carrying out the method according to the invention.

[0002] Membrane separation processes such as reverse osmosis or nanofiltration are frequently used to dealcoholize alcoholic beverages. Membrane separation processes like reverse osmosis and nanofiltration operate at low temperatures, resulting in relatively low energy consumption. A disadvantage of these membrane processes is the high water consumption, which results from the selectivity of the membranes used. Water permeates with a similar specificity to ethanol, so the permeate has a comparable water-to-ethanol ratio to that of the starting liquid being dealcoholized. The volume of water removed from the starting liquid by permeation must be compensated for by adding degassed water from a different product to the remaining retentate. The required amount of degassed water is approximately one and a half to three times the volume of the final product. This process is also known as diafiltration.A disadvantage of this well-known process is that aroma compounds are lost from the retentate and thus also from the final product. Another disadvantage of known membrane separation processes for the dealcoholization of alcoholic beverages, such as reverse osmosis and nanofiltration, is that these processes cannot be used for the dealcoholization of wine, as legal regulations prohibit the addition of water foreign to the wine.

[0003] Membrane separation processes are also known that operate on the principle of pervaporation, whereby the component of the feed liquid diffusing through the membrane evaporates on the secondary side of the membrane. While these pervaporation processes have higher selectivity than water with respect to ethanol due to the different vapor pressure, resulting in lower water consumption, they have the disadvantage that processing liquids containing solids, such as protein-rich liquids like beer, leads to membrane fouling, similar to what is known to occur in reverse osmosis processes using wound-module membranes. This results in a decrease in performance, shorter service life, and increased cleaning effort.

[0004] The increasing demand for non-alcoholic beverages and the growing requirements in the production of these products with regard to energy and resource consumption necessitate the further development of existing dealcoholization processes and suitable equipment.

[0005] The object of the present invention is to provide a method for dealcoholizing a starting liquid containing water and alcohol, in which both water consumption and aroma loss, i.e., the loss of flavorings, are reduced. Furthermore, a device particularly suitable for dealcoholization is to be provided.

[0006] The part of the problem relating to the method is solved by a method having the features of claim 1.

[0007] A process for dealcoholizing a starting liquid containing water and alcohol, in particular ethanol, as well as flavorings and / or nutrients, by means of a first membrane separation unit comprising at least one separation membrane, in particular a diafiltration unit or a reverse osmosis unit, wherein the starting liquid is introduced under overpressure into a primary-side chamber of the first membrane separation unit, in the secondary-side chamber of which, downstream of the at least one separation membrane, a lower pressure prevails than in the primary-side chamber, wherein water and alcohol pass through the at least one separation membrane into the secondary-side chamber as an alcohol-containing liquid permeate, and wherein water or a water-containing liquid is added directly or indirectly as a diluent to a retentate retained by the at least one separation membrane in the primary-side chamber, is characterized by the following:that the alcoholic liquid permeate is further treated in a pervaporation unit of a second membrane separation unit, wherein the alcoholic liquid permeate is first introduced into a primary-side chamber of the pervaporation unit, where the alcohol evaporates at at least one pervaporation membrane and enters as an alcoholic gaseous permeate into a secondary-side chamber of the pervaporation unit downstream of the at least one pervaporation membrane, and wherein the aroma-containing water of the alcoholic liquid permeate is retained as a retentate in the primary-side chamber of the pervaporation unit and reused. Instead of a single pervaporation unit, several pervaporation units arranged in series may also be provided.

[0008] This two-stage membrane dealcoholization process according to the invention significantly reduces both aroma loss and water consumption during dealcoholization.

[0009] Further preferred and advantageous features of the method according to the invention are the subject of dependent claims 2 to 7.

[0010] Preferably, the water retained in the primary-side chamber of the pervaporation unit, i.e., in the second process stage, is indirectly or directly fed back to the retentate of the first membrane separation unit as a dilution liquid and thus reused in the first process stage of diafiltration. In this way, product-specific water is used as the dilution liquid for the retentate to be diluted in the first process stage, and no extraneous water needs to be added. This not only reduces water consumption but also extends the application range of the dealcoholization process according to the invention to the dealcoholization of wine.

[0011] It is also advantageous if the alcohol-containing gaseous permeate from the secondary side of the pervaporation unit is fed to a condensation unit, where any remaining alcohol in the gaseous permeate is condensed and the remaining gaseous water can be removed. Process water can then be recovered from this process-generated water vapor by means of a further condensation unit.

[0012] It is particularly advantageous if the condensed liquid, essentially water, from the condensation unit is returned to the primary-side chamber of the pervaporation unit. Preferably, a buffer tank for the alcohol-containing permeate from the first process stage is provided for this purpose, which is integrated into the circuit of the second process stage. If this condensation liquid still contains alcohol, this residual alcohol is also separated out by this circuit during batch operation.

[0013] The condensate liquid, essentially water, condensed in the condensation unit can preferably be returned to the retentate of the first membrane separation unit or to the alcohol-containing feed liquid introduced into the first membrane separation unit, either as a diluent. This is particularly advantageous when the alcohol has been almost completely removed during batch operation of the second process stage, i.e., the pervaporation unit and the condensation unit. This dilutes the retentate from the first process stage with this additionally recovered, alcohol-free process water.

[0014] According to an advantageous embodiment of the inventive process, which can be combined with other embodiments of the invention, the starting liquid introduced into the primary-side chamber of the first membrane separation unit is circulated and thereby passed several times through the primary-side chamber and over the separation membrane of the first membrane separation unit. Preferably, a buffer tank for the alcohol-containing starting liquid is provided in the first process stage and integrated into the circuit. This batch operation increases the efficiency of alcohol separation in the first process stage.

[0015] According to a further advantageous embodiment of the inventive process, which can be combined with other embodiments of the invention, the alcohol-containing liquid permeate introduced into the primary-side chamber of the pervaporation unit is circulated and thereby passed several times through the primary-side chamber and over the pervaporation membrane of the pervaporation unit. This batch operation increases the efficiency of alcohol separation in the second process stage.

[0016] The dealcoholization process according to the invention combines, as a first process stage, a membrane separation process of diafiltration with a second membrane separation process of pervaporation, which is downstream in the flow direction. The second membrane separation process of pervaporation is suitable for recovering the valuable product components, water and aromas, from the permeate of the first membrane separation process. This aroma-containing water can be returned to the first process stage and used there to dilute the retentate from the first membrane separation process, thereby also returning the aromas to this retentate. If this retentate is dealcoholized, for example after batch operation, it again contains those aromas that were removed from the starting liquid in the first membrane separation process during concentration and, for example, diafiltration.The second process stage therefore serves not only to recover the process water, but also to recover the aromas removed in the first process stage, i.e., in the first membrane separation process.

[0017] For the economical operation of a dealcoholization device carrying out the process according to the invention, it is advantageous if the alcohol content of the retentate from the pervaporation in the second process stage, i.e., the liquid returned to the first process stage of the first membrane separation process, for example diafiltration or reverse osmosis, has a low alcohol content of preferably less than 1.5 vol.%, more preferably less than 1.0 vol.%, more preferably less than 0.5 vol.%, and more preferably less than 0.05 vol.%.

[0018] The permeate from the first process stage has a low viscosity, contains no solids, and has a low ion content. These properties make it a very suitable starting material for ethanol removal by pervaporation in the second process stage, as it does not exhibit any tendency to foul. Thus, the combination of both membrane separation processes according to the invention is more efficient than direct dealcoholization by pervaporation alone.

[0019] The part of the problem relating to the device is solved by a device, in particular designed for carrying out a method according to the invention, having the features of claim 8.

[0020] A device for dealcoholizing a starting liquid containing water and alcohol, in particular ethanol, as well as flavorings and / or nutrients, is provided with a first membrane separation unit forming a first separation stage, which is preferably designed as a diafiltration unit or reverse osmosis unit, or preferably has a diafiltration unit or reverse osmosis unit, and with a second membrane separation unit forming a second separation stage, which is arranged downstream of the first separation stage in the process direction and is designed as a pervaporation unit, or has a pervaporation unit, wherein a permeate outlet of the first separation stage is or can be brought into fluid contact with a liquid inlet of the second separation stage, either directly or indirectly.Such a two-stage dealcoholization device combines the advantages of the first membrane separation unit in the first separation stage with the advantages of the second membrane separation unit for pervaporation in the second separation stage without having to accept their respective disadvantages and also enables the recovery of aromas and process water.

[0021] Further preferred and advantageous design features of the device according to the invention are the subject of dependent claims 9 and 10.

[0022] It is particularly advantageous if a condensation unit is located downstream of the pervaporation unit in the second separation stage, whereby a permeate outlet of the second separation stage is directly or indirectly connected to a fluid inlet of the condensation unit. This improves the recovery of aromas and process water.

[0023] It is advantageous if a condensation fluid outlet of the condensation unit is in fluid contact with, or can be brought into contact with, the primary-side space of the pervaporation unit or with a dilution fluid inlet of the first separation stage.

[0024] Preferred embodiments of the invention with additional design details and further advantages are described and explained in more detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] It shows: Fig. 1 a process scheme of a device carrying out the process according to the invention for dealcoholization.

[0026] In Fig. Figure 1 schematically depicts a device 100 for dealcoholizing a liquid containing water and alcohol, for example, a beverage such as beer or wine. This device 100 performs a dealcoholizing process in which the process direction P runs from left to right. That is, the individual process steps are carried out in the device from left to right. Fig. 1. Go through.

[0027] The device 100 operates on the principle of separation of substances using permeable membranes 12, 22 and consecutively applies two different membrane separation processes, thus having a two-stage design. A first separation stage 101 is formed by a first membrane separation unit 1, and a second membrane separation unit 2, downstream of the first separation stage 101 in the process direction P, is part of a second separation stage 102.

[0028] The first membrane separation unit 1 of the first separation stage 101 operates in the example shown according to the principle of diafiltration, for example microfiltration, ultrafiltration or nanofiltration. However, it can also operate, for example, according to the principle of reverse osmosis or another membrane separation process in which a liquid diffuses through a membrane.

[0029] In the example shown, the first membrane separation unit 1 has a diafiltration unit 10 or is designed as a diafiltration unit. The diafiltration unit 10 has a filter housing 11 in which a separation membrane 12 is arranged, which divides the interior of the filter housing 11 into a primary-side chamber 13 and a secondary-side chamber 14.

[0030] The second membrane separation unit 2 of the second separation stage 102 operates on the principle of pervaporation and includes a pervaporation unit 20. The pervaporation unit 20 has a filter housing 21 in which a pervaporation membrane 22 is arranged, which divides the interior of the filter housing 21 into a primary-side chamber 23 and a secondary-side chamber 24. Also part of the second separation stage 102 is a condensation unit 3 downstream of the pervaporation unit 20 in the process direction, comprising a condensation unit 30, which includes a condenser 31 and a condensate collection tank 32 with a condensate outlet 34.

[0031] A first buffer tank 15, associated with the first membrane separation unit 1, serves to hold the starting liquid F to be treated, containing water and alcohol, for example, an alcoholic beverage liquid. A second buffer tank 25, associated with the second membrane separation unit 2, serves to hold the intermediate product liquid Z containing a first permeate P1 from the first membrane separation unit 1.

[0032] The individual components of the device 100 are connected to each other via fluid lines of a fluid line system 4. Fig. Figure 1 also shows a CIP cleaning unit 5 for the buffer tanks 15, 25 which can be supplied with a CIP cleaning fluid, with a supply line 50 and spray heads 51, 52 provided in the buffer tanks 15, 25, which, however, is not essential to the invention.

[0033] A liquid outlet 15' of the first buffer tank 15 is connected via a first supply line 40 of the fluid piping system 4 to a liquid inlet 13' of the primary-side chamber 13 of the diafiltration unit 10. A pressure booster pump 40' and a circulation pump 40" are provided in the first supply line 40.

[0034] The initial liquid F is introduced from the first buffer tank 15 through the first feed line 40 under pressure into the primary-side chamber 13 of the diafiltration unit 10. A portion of this liquid, namely alcohol and water with dissolved aromas, is forced from the primary-side chamber 13 through the separation membrane 12 into the secondary-side chamber 14, where it forms a first permeate P1. The liquid remaining in the primary-side chamber 13 forms a first retentate R1, which is either returned to the first buffer tank 15 via a first return line 41 or circulated in a closed loop by the recirculation pump 40" through a recirculation line 42 to the liquid inlet 13' of the primary-side chamber 13. In this closed loop, not only is the alcohol content remaining in the retentate reduced and the viscosity of the retentate increased due to the water loss, but the aroma content in the first retentate R1 is also reduced.To prevent the first retentate R1 from becoming too viscous, water or a water-containing dilution liquid V from an external source Q or - as described below - as a return flow from the second membrane separation unit 2 is introduced through a return line 49 into the first supply line 40 to dilute the first retentate R1.

[0035] The first permeate P1 leaving the diafiltration unit 10 is conveyed either through a first transfer line 43 into the second buffer tank 25 or through a second transfer line 44, into which an outlet 45 of the second buffer tank 25 also opens, to a liquid inlet 23' of the primary-side chamber 23 of the pervaporation unit 20, and enters the primary-side chamber 23 there. A feed pump 44', a circulation pump 44" and a heating device 44''' are provided in the second transfer line 44. This heating device 44''' can utilize waste heat generated in the first separation stage 101.

[0036] The first permeate P1, heated by the heating device 44", enters the pervaporation membrane 22 from the primary-side chamber 23 of the pervaporation unit 20, evaporating into the secondary-side chamber 24. This vapor, forming a second permeate P2, is directed from the secondary-side chamber 24 into the condenser 31 of the condensation device 3, where the vaporous second permeate P2, along with the aromas it contains, condenses and is collected as condensed liquid in the condensate collection tank 32. The uncondensed, still gaseous portion can be removed in its gaseous phase G by means of a vacuum pump 33.

[0037] The condensate K collected in the condensate collection tank 32 consists essentially of the process water containing the aromas, with a small amount of alcohol still present. This condensate K can be discharged from the device 100 via a condensate outlet 35, or it can be pumped back into the second buffer tank 25 via a second return line 46 using a further pump 46'. From there, it can be recirculated through the pervaporation unit 20 and, as a second permeate P2, through the condensation unit 30, where the alcohol content can be further reduced.

[0038] The liquid portion of the first permeate P1 that does not pass through the pervaporation membrane 22 remains as the second retentate R2 in the primary-side chamber 23 of the pervaporation unit 20 and is either returned to the second buffer tank 25 via a third return line 47 or flows back into the primary-side chamber 23 of the pervaporation unit 20 via a second recirculation line 48, driven by the second recirculation pump 44'', thus further reducing the alcohol content in the second retentate R2. A fourth return line 49 allows the reduced second retentate R2, i.e., essentially alcohol-free water with its contained aromas, to be returned as process water to the first feed line 40.

[0039] The aromas removed from the starting liquid F containing the alcohol and a portion of the water in the first separation stage 101 are recovered in the second separation stage 102. At the end of each batch process, the alcohol-free condensate K containing the aromas is discharged from the apparatus 100 for further use and can be mixed with the dealcoholized first retentate R1 to produce an alcohol-free beverage liquid.

[0040] Reference numerals in the claims, description and drawings serve only to improve understanding of the invention and are not intended to limit the scope of protection. Reference symbol list

[0041] It refers to: 1 first membrane separation unit 2 second membrane separation unit 3 Condensation device 4 Fluid piping system 5 CIP cleaning units 10 diafiltration units 11 filter housings 12 permeable separation membrane 13 primary-side space 13' Fluid inlet 14 secondary-side rooms 15 first buffer tank 15' Liquid outlet 20 pervaporation units 21 filter housings 22 Pervaporation membrane 23 primary-side space 23' Fluid inlet 24 secondary-level rooms 25 second buffer tank 30 condensation units 31 Capacitor 32 Condensate collection tank 33 Vacuum pump 34 Condensation fluid leakage 35 Condensate outlet 40 first supply line 40' booster pump 40" circulation pump 41 first return line 42 Circulation line 43 first transfer line 44 second transfer line 44' feed pump 44'' second circulation pump 44''' Heating unit 45 Outlet of the second buffer tank 25 46 second return line 46' Pump 47 third return line 48 second circulation line 49 fourth return line 50 CIP supply line 51 spray head 52 spray heads 100 Dealcoholization device 101 First stage of material separation 102 second material separation stage F Starting fluid G Gas phase K Condensate P1 first permeate P2 second permeate R1 first retent R2 second retentate V Dilution fluid Z Intermediate product liquid

Images