METHOD FOR ENRICHING AQUEOUS ETHANOLIC SOLUTION IN ETHANOL

Abstract

The present disclosure relates to a method for enriching an aqueous ethanolic solution in ethanol, including the steps of providing a forward osmosis membrane module with a first chamber, a second chamber and a semi-permeable membrane separating the first and the second chamber, coupling an inlet of the first chamber fluidly to a source of an aqueous ethanolic solution, coupling an inlet of the second chamber fluidly to a source for a concentrated draw solution, and recovering an aqueous ethanolic solution enriched in ethanol at an outlet of the first chamber and a diluted draw solution at the outlet of the second chamber.

Claims

1. A method for enriching an aqueous ethanolic solution in ethanol, comprising the steps of: a. Providing a forward osmosis membrane module comprising a first chamber, a second chamber and a semi-permeable membrane separating the first and the second chamber, b. Coupling an inlet of the first chamber fluidly to a source of an aqueous ethanolic solution, c. Coupling an inlet of the second chamber fluidly to a source for a concentrated draw solution, and d. Recovering an aqueous ethanolic solution enriched in ethanol at an outlet of the first chamber and a diluted draw solution at the outlet of the second chamber, wherein the forward osmosis membrane module is a hollow fiber (HF) module, the semi-permeable membrane comprises a support layer covered by a Thin Film Composite (TFC) layer, and aquaporin water channels are incorporated into the TFC layer of the semipermeable membrane, and wherein the TFC layer is obtained by interfacial polymerization of a polyfunctional amine and a polyfunctional acid.

2-35. (canceled)

36. The method according to claim 1, wherein the TFC layer of the membrane is facing the aqueous ethanolic solution to be enriched.

37. The method according to claim 1, wherein the TFC layer is present on the inside of the fibers.

38. The method according to claim 1, wherein the lumen of the hollow fibers constitutes the first chamber and the second chamber is constituted by the space around the exterior of the fibers.

39. The method according to claim 1, wherein the aqueous ethanolic solution is treated in the forward osmosis membrane module until at least 50% of the weight thereof has been recovered in the draw solution.

40. The method according to claim 1, wherein the concentration of ethanol in the starting aqueous ethanolic solution is less than 20%.

41. The method according to claim 39, wherein the aqueous ethanolic solution is beer or ale.

42. The method according to claim 39, wherein the aqueous ethanolic solution is wine.

43. A method for enriching an aqueous ethanolic solution in ethanol, comprising the steps of: a. Providing a forward osmosis membrane module comprising a first chamber, a second chamber and a semi-permeable membrane separating the first and the second chamber, b. Coupling an inlet of the first chamber fluidly to a source of an aqueous ethanolic solution, c. Coupling an inlet of the second chamber fluidly to a source for a concentrated draw solution, and d. Recovering an aqueous ethanolic solution enriched in ethanol at an outlet of the first chamber and a diluted draw solution at the outlet of the second chamber, wherein the forward osmosis membrane module is a hollow fiber (HF) module, the semi-permeable membrane comprises a support layer covered by a Thin Film Composite (TFC) layer, and aquaporin water channels are incorporated into the TFC layer of the semipermeable membrane, wherein the TFC layer is obtained by interfacial polymerization of a polyfunctional amine and a polyfunctional acid, and wherein the aquaporin water channels are assembled in a nanostructure comprising polyalkyleneimine.

44. The method according to claim 43, wherein the polyalkyleneimine is polyethyleneimine.

45. The method according to claim 44, wherein the polyethyleneimine has an average molecular weight of between about 2,000 Da to about 10,000 Da.

46. The method according to claim 43, wherein the aquaporin water channel is solubilized in a detergent prior to the assembling in a nanostructure comprising polyalkyleneimine.

47. The method according to claim 46, wherein the detergent is selected from the group consisting of lauryl dimethylamine N-oxide (LDAO), octyl glucoside (OG), dodecyl maltoside (DDM) or a combination thereof.

48. A method for enriching an aqueous ethanolic solution in ethanol, comprising the steps of: a. Providing a forward osmosis membrane module comprising a first chamber, a second chamber and a semi-permeable membrane separating the first and the second chamber, b. Coupling an inlet of the first chamber fluidly to a source of an aqueous ethanolic solution, c. Coupling an inlet of the second chamber fluidly to a source for a concentrated draw solution, and d. Recovering an aqueous ethanolic solution enriched in ethanol at an outlet of the first chamber and a diluted draw solution at the outlet of the second chamber, wherein the forward osmosis membrane module is a hollow fiber (HF) module, the semi-permeable membrane comprises a support layer covered by a Thin Film Composite (TFC) layer, and aquaporin water channels are incorporated into the TFC layer of the semipermeable membrane, wherein the TFC layer is obtained by interfacial polymerization of a polyfunctional amine and a polyfunctional acid, and wherein the aquaporin water channels are provided in a vesicle prior to the incorporation in the TFC layer.

49. The method according to claim 48, wherein the vesicle comprises an amphiphilic diblock copolymer of the PMOXA-PDMS type and a reactive end group functionalized PDMS.

50. The method according to claim 49, wherein said PMOXA-PDMS is selected from the group consisting of PMOXA.sub.10-40-PDMS.sub.25-70 and mixtures thereof.

51. The method according to claim 50, wherein the mixture comprises at least a first amphiphilic diblock copolymer of the general formula PMOXA.sub.10-28-PDMS.sub.25-70 and a second amphiphilic diblock copolymer of the general formula PMOXA.sub.28-40-PDMS.sub.25-70.

52. The method according to claim 48, wherein said reactive end group functionalised PDMS is functionalized with one or more of amine, carboxylic acid, and/or hydroxy groups.

53. The method according to claim 48, further comprising from about 1% v/v to about 12% v/v of triblock copolymer of the PMOXA-PDMS-PMOXA type.

54. The method according to claim 48, wherein the vesicle further comprises a flux improving agent.

Description

EXAMPLE 1

[0055] Ethanol Enrichment of Beer

[0056] A HFFO2/220 element available from Aquaporin, Denmark, was used in this experiment for concentrating ethanol in beer. Initially, the membrane was flushed for 30 min with DI water and stored at 4° C.

[0057] 40 kg of Royal Classical Pilsner available from Royal Unibrew, Denmark was continuously conveyed through the lumen of the hollow fibers using a gear pump adjusted to a volumetric velocity of 60 L/h at the outlet of the module. The initial ethanol concentration in the beer was 4.6 vol % corresponding to 31.55 g/L. A draw solution of 2M MgCl.sub.2 was delivered in continuous mode and adjusted by a gear pump to a volumetric velocity of 25 L/h at the outlet of the module.

[0058] The weight increase of the draw solution was used to calculate the recovery rate, i.e. the amount of matter exchanged between the beer and the draw solution, and the flux. The initial flux was measured as 10,24 LMH.

[0059] After recovery of 87% of the feed mass in the draw solution a sample was collected and analyzed. The analysis showed that the amount of ethanol in the feed solution was 165.65 g/L corresponding to the ethanol rejection being 90.43%.

EXAMPLE 2

[0060] Alcohol Enrichment of Alcoholic Aqueous Solution

[0061] A HFFO2/220 element available from Aquaporin, Denmark, was used in this experiment for concentrating ethanol in an aqueous ethanolic solution. Initially, the membrane was flushed for 30 min with DI water and stored at 4° C.

[0062] 28.6 kg of alcoholic aqueous solution was continuously conveyed through the lumen of the hollow fibers using a gear pump adjusted to a volumetric velocity of 60 L/h at the outlet of the module. The initial ethanol concentration in the solution was 5 vol % corresponding to 32.15 g/L. A draw solution of 2M MgCL.sub.2 was delivered to the module in continuous mode and adjusted by a gear pump to a volumetric velocity of 25 L/h at the outlet of the module.

[0063] The weight increase of the draw solution was used to calculate the recovery rate, i.e. the amount of matter exchanged between the aqueous ethanolic solution and the draw solution, and the flux. The initial flux was measured as 14.87 LMH.

[0064] After recovery of 83.8% of the feed mass in the draw solution a sample was collected and analyzed. The analysis showed that the amount of ethanol in the feed solution was 205.27 g/L corresponding to the ethanol rejection being 68.08%.

EXAMPLE 3

[0065] The HFFO2/220 element (Aquaporin Inside® FO) was compared with other commercially available forward osmosis membranes. The results are shown in FIG. 1.

[0066] HTI TFC FO is a membrane available from Hydration Technology Innovations (HTI) under the trademark OsMEM™. The membrane is of the flat sheet type having a Thin Film Composite (TFC) layer. The flat sheet membrane is provided on a durable woven backing and spiraled into a module. The NaCl rejection is specified to 99.4%.

[0067] HTI CTA FO is a membrane available from Hydration Technology Innovations (HTI) under the trademark OsMEM™. The membrane is produced of cellulose triacetate and provided with a woven backing. The membrane and the backing are spiral wound to produce the membrane module.

[0068] Alfa Laval CTA RO is a spiral wound membrane module produced from a flat sheet membrane of cellulose triacetate.

[0069] For the FO experiments, the feed solution was an aqueous ethanolic solution of 4.5% EtOH in water and the draw solution was 2M MgCl.sub.2 for the HFFO2/220 element, whereas 1 M NaCl was used for the HTI elements. For the RO experiment, a beer having an ethanol concentration of 5.5% was used as the feed solution and 30 bar was applied as the feed pressure.

[0070] Surprisingly, the data in FIG. 1 shows that a higher ethanol rejection is obtained by the HFFO2 hollow fiber module.

EXAMPLE 4

[0071] To investigate the results of example 3 further, a hollow fiber module was prepared without aquaporins in the TFC layer of the membrane. The purpose was to find out if it was the presence of aquaporins in the membrane that accounted for the ethanol rejection.

[0072] The hollow fiber module was prepared as disclosed in WO2017137361, however without adding PEI-APQ Z to the MPD (m-phenylene diamine) solution. More specifically, MPD was dissolved in MilliQ water in a concentration of 2.5% (w/w). The MPD solution was filled into the lumen of the fibers in a UF hollow fiber module having a total membrane area of 2.2 m.sup.2 at a flow rate of 5 mL/min. After 1 min the flow was stopped and the fibers were left for soaking for 1 min. Then, the module was emptied and purge with air to get surplus MPD solution out. To remove surface water from the lumen of the fibers an air flow was used having a flow rate of 25 L/min. Subsequently, a mild vacuum was applied to the shell side of the module to promote uniform drying of the aqueous phase.

[0073] A TMC solution was prepared by dissolving benzene-1,3,5-tricarbonyl chloride (Trimesoyl Chloride—TMC) in hexane to obtain a final concentration of 0.25% (w/v). The TMC solution was pumped into the module using a flow rate of 15 mL/min. After the module was filled the pumping was continued for 30 s. Subsequently, the module was turned upside down to empty it for free-flowing liquid. Then the module was connected to air and purged at 10 L/min for 5-10 s. Finally, the lumen of the fibers in the membrane module was rinsed with MilliQ water. The active layer of the TMC layer was measure to between 83 nm to 104 nm in a SEM image.

[0074] The hollow fiber module without aquaporins in the TFC layer but otherwise similar to the HFFO2 module is termed HFFO2 (-AQP). The HFFO2 module and the HFFO2 (-AQP) were tested on a feed solution comprising 5% EtOH in RO water at a flow rate of 1000 mL/min in batch mode. The draw solution was 2 M or 2.4 M MgCl.sub.2 and supplied to the module at a flow rate of 416 mL/min. Each test was performed twice (n=2) to obtain statistical data samples.

[0075] The data show that after about 50% recovery the HFFO2 module and the HFFO2 (-AQP) had a similar ethanol rejection. The same tendency appeared after about 80% and about 90% recovery. The water flux was at a similar level for the HFFO2 module and the HFFO2 (-AQP) at 50% recovery. However, after about 80% and about 90% recovery the water flux was substantially higher for the HFFO2 module. In short, the presence or absence of aquaporins in the TFC layer do not substantially affects the ethanol rejection property. The water flux is, however, substantially higher for the hollow fiber module comprising aquaporins.