Method and system for separating fusel oil in ethanol fermentation process and application thereof

Abstract

The present application relates to the field of ethanol production, and discloses a method and system for separating fusel oil in an ethanol fermentation process and application thereof, the method comprising: subjecting mature mash to crude distillation in a crude distillation column and a crude auxiliary column to obtain waste mash, crude auxiliary column bottom liquid and crude distillation fraction; subjecting the waste mash to solid-liquid separation to obtain clear liquid; subjecting the clear liquid to evaporation and concentration to obtain evaporation condensate; subjecting the crude distillation fraction to rectification to obtain rectification column fusel and ethanol; subjecting the rectification column fusel to separation to obtain fusel oil and light wine; wherein the separation mode comprises: sequentially mixing the crude auxiliary column bottom liquid and / or evaporation condensate with the rectification column fusel and optional process water, cooling and separating fusel oil to obtain fusel oil and light wine. The method of the present application can improve the separation effect of fusel oil, reduce the content of fusel oil in light wine and industrial wine, and solve or greatly alleviate the problem of fouling in the recovery column.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of ethanol production, in particular to a method for separating fusel oil in the process of fermentation for producing ethanol, a system for separating fusel oil in the process of fermentation for producing ethanol and application of the system in the process of fermentation for producing ethanol. BACKGROUND

[0002] Fusel oil is one of the by-products of fermentation for producing alcohol from starch and cellulose raw materials, and is a mixture of various alcohols. Fusel oil is soluble in high-concentration ethanol but not in low-concentration ethanol and water, and is a colorless to light yellow volatile oil liquid mainly composed of more than ten substances such as n-propanol, isoamyl alcohol, isobutyl alcohol and ethyl caprate. The generation of fusel oil is related to fermentation raw materials and process, and is generated by deamination and decarboxylation of protein decomposition products such as leucine, isoleucine and valine through yeast metabolism in the process of fermentation for producing alcohol, and the general generation is about 0.2%-0.7% of the alcohol yield.

[0003] In the process of alcohol distillation, fusel oil is generally enriched on several tower plates (alcohol concentration 55-75% (v / v)) above the feeding tower plate of the rectification tower and the fusel fraction containing tower (such as recovery tower), and a fusel oil sampling point is usually set at this position. After being sampled out, it is usually diluted with process water, and then enters the fusel oil separator to be extracted and separated at low temperature to obtain fusel oil, and the remaining light wine is stored in the light wine tank. The fusel oil separator is used as a fusel oil separation device, and adopts an automatic overflow method for oil-water separation. The density of fusel oil is smaller than that of light wine, so it is in the upper part of the separator and enters the fusel oil tank through the overflow port, and the light wine is distilled and concentrated in the recovery tower.

[0004] However, it is found in the production process that although the addition of process water to adjust the alcohol concentration in the fusel wine can achieve the separation of fusel oil and light wine, it not only increases the consumption of process water, but also the content of fusel oil in the separated light wine is high, and the separation efficiency is low. SUMMARY

[0005] The purpose of the present application is to overcome the low separation efficiency problem of the prior art when process water is used to dilute the fusel wine sampled from the rectification tower for separating fusel oil, and to provide a method for separating fusel oil in the process of fermentation for producing ethanol, a system for separating fusel oil in the process of fermentation for producing ethanol and application of the system in the process of fermentation for producing ethanol. The method can improve the separation efficiency of fusel oil, reduce the content of fusel oil in light wine and industrial alcohol, and solve or greatly alleviate the problem of fouling in the recovery tower.

[0006] In order to achieve the above-mentioned purpose, the first aspect of the present application provides a method for separating fusel oil in the process of fermentation for producing ethanol, which comprises:

[0007] (1) subjecting the matured mash to a rough distillation in a rough distillation column and a rough auxiliary column to obtain a waste mash, a rough auxiliary column bottom liquid, and a rough distillation fraction;

[0008] (2) subjecting the waste mash obtained in step (1) to a solid-liquid separation to obtain a clear liquid; and subjecting the clear liquid to an evaporation concentration to obtain an evaporation condensate;

[0009] (3) subjecting the rough distillation fraction to a rectification to obtain a rectification column impurity liquor and ethanol;

[0010] (4) subjecting the rectification column impurity liquor to a separation to obtain fusel oil and light wine;

[0011] In step (4), the separation includes: sequentially mixing the rough auxiliary column bottom liquid obtained in step (1) and / or the evaporation condensate obtained in step (2) with the rectification column impurity liquor and optional process water, cooling, and separating fusel oil to obtain fusel oil and light wine.

[0012] The second aspect of the present application provides a system for separating fusel oil in a fermentation process for producing ethanol, which comprises:

[0013] a mixing unit connected to the rough auxiliary column and / or the evaporation unit through pipelines and connected to the rectification column through pipelines, for mixing the rough auxiliary column bottom liquid from the rough auxiliary column and / or the evaporation condensate from the evaporation unit with the rectification column impurity liquor from the rectification column;

[0014] a cooling unit connected to the mixing unit through pipelines, for cooling the mixed liquid from the mixing unit;

[0015] a fusel oil separation unit connected to the cooling unit through pipelines, for separating the material from the cooling unit to obtain fusel oil and light wine.

[0016] The third aspect of the present application provides the use of the system as described above in the separation of fusel oil in a fermentation process for producing ethanol.

[0017] The technical solution of the present application can improve the separation efficiency of fusel oil and reduce the content of fusel oil in light wine and industrial wine.

[0018] The rough auxiliary column bottom liquid and the evaporation condensate are both waste water generated in the ethanol production process, generally part of which is used for slurry adjustment, and the remaining part enters a sewage treatment unit. Replacing the process water with these two materials for fusel oil separation not only reduces the consumption of process water, but also reduces the pressure of sewage treatment and reduces production costs.

[0019] In addition, the method described in the present application can also solve the problem of scaling of pipelines, pumps and recovery column trays when only using process water for dilution, thereby ensuring the normal operation of the recovery column. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 This is a flowchart of the separation of fusel oil during the fermentation process for ethanol production as described in this invention. Detailed Implementation

[0021] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0022] The first aspect of this invention provides a method for separating fusel oil during ethanol production through fermentation, the method comprising:

[0023] (1) The mature mash is distilled in a crude distillation column and a crude auxiliary column to obtain waste mash, bottom liquid of the crude auxiliary column and crude distillate;

[0024] (2) The waste mash obtained in step (1) is subjected to solid-liquid separation to obtain a clear liquid; the clear liquid is then evaporated and concentrated to obtain an evaporation condensate;

[0025] (3) The crude distillate is purified by distillation to obtain distillate and ethanol;

[0026] (4) Separate the mixed wines from the distillation column to obtain fusel oil and light wine;

[0027] In step (4), the separation method includes: mixing, cooling and separating fusel oil from the crude auxiliary tower bottom liquid obtained in step (1) and / or the evaporation condensate obtained in step (2) with the distillation tower miscellaneous wine and optional process water in sequence to obtain fusel oil and light wine.

[0028] In this invention, the fermentation process for producing ethanol can use any raw material suitable for ethanol production, such as starchy or cellulose raw materials. Starchy raw materials can be grains (e.g., corn, rice, wheat), tubers (sweet potatoes, cassava, and potatoes), and sugars (waste molasses), while cellulose raw materials can be crop straw, waste wood, and waste pulp.

[0029] Starchy raw materials can be crushed, mixed into a slurry, liquefied, saccharified, and fermented to obtain mature mash. Saccharification and fermentation can be carried out simultaneously, or saccharification can be performed first and then fermentation.

[0030] Cellulose raw materials can be crushed, pretreated, enzymatically hydrolyzed, and fermented to obtain mature mash.

[0031] The specific preparation method of mature mash can be obtained by any method in the art, without any particular limitation, and those skilled in the art can choose according to their needs.

[0032] In the present application, the ethanol content of the matured mash can be selected in a wide range, preferably, the ethanol content of the fermented matured mash is 7-18% by volume, such as can be 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18% by volume and any range consisting of any two values between them, preferably 10-15% by volume.

[0033] The process of treating the matured mash to obtain ethanol can also be any method in the art, for example, the matured mash can be sequentially subjected to crude distillation and rectification to obtain ethanol.

[0034] The method and conditions of crude distillation can be conventional in the art, as long as ethanol can be produced. Generally, the matured mash is distilled in a crude distillation column, and the wine liquid is taken out from the middle part of the crude distillation column and concentrated in a crude auxiliary column. The concentrated wine vapor returns to the middle part of the crude distillation column, and the concentrated waste water without alcohol is discharged from the bottom of the crude auxiliary column, which is the crude auxiliary column liquid. The material discharged from the bottom of the crude distillation column is waste mash.

[0035] Preferably, in step (1), the working conditions of the crude distillation column include: the bottom temperature is 70-90℃, the bottom pressure is -0.025MPa to -0.045MPa; the top temperature is 50-70℃; the top pressure is -0.05MPa to -0.08MPa.

[0036] Preferably, in step (1), the working conditions of the crude auxiliary column include: the bottom temperature is 75-85℃, the bottom pressure is -0.01MPa to -0.02MPa; the top temperature is 60-70℃; the top pressure is -0.03MPa to -0.06MPa.

[0037] Preferably, the temperature of the crude auxiliary column liquid is 75-85℃ (such as can be 75, 77, 79, 81, 83, 85℃ and any range consisting of any two values between them), and the pH is 3-4.5 (such as can be 3, 3.3, 3.6, 3.9, 4.2, 4.5 and any range consisting of any two values between them).

[0038] Preferably, the working conditions of the rectification column include: the bottom temperature is 125-145℃, the bottom pressure is 0.2-0.3MPa; the top temperature is 105-115℃; the top pressure is 0.15-0.25MPa.

[0039] Unless otherwise specified, the pressure refers to the gauge pressure.

[0040] In the present application, the method and conditions for preparing the evaporation condensate from the waste mash can be conventional in the art, which can be selected by those skilled in the art as needed.

[0041] The solid-liquid separation method can be a method commonly used in the art, such as centrifugation or filtration.

[0042] The evaporation and concentration method can be a method commonly used in the art, such as four-effect evaporation, which can be used to obtain sugar syrup and evaporation condensate.

[0043] Preferably, the evaporation condensate has a temperature of 50-75℃ (such as 50, 55, 60, 65, 70, 75℃, and any range between any two values), and a pH of 3-4.5 (such as 3, 3.3, 3.6, 3.9, 4.2, 4.5, and any range between any two values).

[0044] Depending on the distillation system, the crude distillation fraction can be distilled in a rectifying column, or the light wine obtained by treating the crude distillation fraction in a water washing column can be distilled in a rectifying column, and the rectifying column impurities are collected from the middle part of the column, and the high-concentration alcohol is collected from the top of the column. Those skilled in the art can select different distillation systems to obtain the rectifying column impurities.

[0045] The distillation method can be a method commonly used in the art, and those skilled in the art can select appropriate number and type of columns and appropriate distillation conditions according to needs.

[0046] The rectifying column impurities are collected at a temperature commonly used in the art, and preferably, the rectifying column impurities are collected at a temperature of 110-130℃.

[0047] Preferably, the rectifying column impurities contain 50-75% by volume of ethanol and 5-20% by volume of fusel oil.

[0048] In the present application, the crude auxiliary column bottom liquid obtained in step (1) and / or the evaporation condensate obtained in step (2) can be used to dilute the material containing fusel oil (such as the rectifying column impurities and the recycled column impurities described below) instead of process water.

[0049] The crude auxiliary column bottom liquid and the evaporation condensate can be used simultaneously or alternatively, and the separation effect of fusel oil using the evaporation condensate is better than that using the crude auxiliary column bottom liquid, the yield of fusel oil is higher, and the content of fusel oil in the light wine and industrial wine is lower.

[0050] Preferably, in step (4), the amounts of the crude auxiliary column kettle liquid, the evaporation condensate liquid and the process water are such that the ethanol content in the mixed liquid is 5-15% by volume (such as 10, 11, 12, 13, 14, 15% by volume and any range between any two values), more preferably 5-10% by volume, and the pH of the mixed liquid is 3.5-5.5 (such as 3.5, 3.7, 3.9, 4.1, 4.3, 4.5, 4.7, 4.9, 5.1, 5.3, 5.5 and any range between any two values), more preferably 3.5-4.5.

[0051] In the present application, the process water can be any water that can be used as production water, such as groundwater, deep well water or river water treated by simple physical filtration, tap water, distilled water, etc.

[0052] The mixing can be carried out in a mixing device conventional in the art, such as a reactor with stirring, or other pipes or devices that can mix, such as a Venturi converging pipe. When a Venturi converging pipe is used, the material flows from the diverging end to the converging end of the Venturi converging pipe, so that the flow rate of the material changes from slow to fast, and the mixing is achieved.

[0053] Preferably, the mixing is carried out in a Venturi converging pipe; in the case of using a Venturi converging pipe, the fusel alcohol and other materials can be mixed intensively and sufficiently, which is beneficial to destroying the state of the fusel oil emulsion and promoting the separation of oil and water.

[0054] In the present application, the mixing process can also include heating or temperature control equipment for controlling the temperature during the mixing process.

[0055] Preferably, the conditions of the mixing include a temperature of 50-100°C (such as 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100°C and any range between any two values), more preferably 60-85°C; under the preferred conditions, the separation effect of fusel oil can be further improved, so that the content of fusel oil in the light wine and industrial wine is lower, and the energy consumption can be kept low. Although a higher mixing temperature can further improve the separation effect of fusel oil, because both the heating of the material and the subsequent cooling process increase the energy consumption, from the aspects of energy consumption and fusel oil separation effect, the best effect is achieved at 70-85°C.

[0056] The mixed liquid obtained by the mixing can be cooled in a heat exchange device, and preferably, the cooling conditions include a temperature of 4-30°C (such as 4, 10, 15, 20, 25, 30°C and any range between any two values), preferably 10-25°C.

[0057] The cooled material is subjected to fusel oil separation to obtain fusel oil and light wine, preferably, the fusel oil separation is carried out in a fusel oil separator.

[0058] The fusel oil separator, as a separation device for fusel oil, can separate oil and water in an automatic overflow manner. The density of fusel oil is less than that of light wine, so it is in the upper part of the separator and enters the fusel oil tank through the overflow port. The light wine is discharged from the bottom of the separator and can be stored in a light wine tank or transported to a recovery column for distillation again to obtain recovery column fusel wine and industrial wine.

[0059] In the present application, preferably, the method further comprises: distilling the light wine obtained in step (4) in a recovery column to obtain recovery column fusel wine and industrial wine.

[0060] Preferably, the working conditions of the recovery column include: the bottom temperature is 105-115℃, the bottom pressure is 0.04-0.06MPa; the top temperature is 75-85℃; and the top pressure is 0.01-0.03MPa.

[0061] It should be understood that the recovery column fusel wine also contains a certain amount of fusel oil.

[0062] Preferably, the method further comprises: refluxing the recovery column fusel wine to step (4) to separate together with the rectification column fusel wine to obtain fusel oil and light wine.

[0063] The separation method is the same as above and will not be repeated here.

[0064] In the present application, the pH of the recovery column bottom liquid is preferably 5-7.

[0065] In the present application, the content of fusel oil can be determined by gas chromatography. Since the main components of fusel oil are n-propanol, isobutyl alcohol and isoamyl alcohol (accounting for more than 95% by volume), the content of fusel oil in the present application is calculated based on the total content of n-propanol, isobutyl alcohol and isoamyl alcohol.

[0066] In a preferred embodiment of the present application, as Figure 1As shown, the mature mash is subjected to rough distillation in the rough distillation column and the rough auxiliary column to obtain waste mash, rough auxiliary column bottom liquid and rough distillation fraction; the waste mash is subjected to solid-liquid separation to obtain clear liquid; the clear liquid is subjected to evaporation concentration to obtain evaporation condensate; the rough distillation fraction is subjected to rectification to obtain rectification column impurities (alcohol-containing material) and ethanol; the rectification column impurities are subjected to separation to obtain fusel oil and light wine; the separation mode comprises: the rough auxiliary column bottom liquid and / or the evaporation condensate are sequentially mixed with the rectification column impurities and optional process water, and then subjected to cooling and fusel oil separation to obtain fusel oil and light wine; the light wine is subjected to distillation in the recovery column to obtain recovery column impurities (alcohol-containing material) and industrial wine; the recovery column impurities are subjected to separation together with the rectification column impurities to obtain fusel oil and light wine.

[0067] In a most preferred embodiment of the present application, the temperature of the rough auxiliary column bottom liquid is 75-85°C, and the pH is 3.5-4; the temperature of the evaporation condensate is 60-70°C, and the pH is 3.3-3.8. The amounts of the rough auxiliary column bottom liquid, the evaporation condensate and the process water are such that the ethanol content in the mixed liquid is 8-10% by volume, and the pH of the mixed liquid is 3.8-4.5. The conditions for the mixing include: temperature 70-80°C; the conditions for the cooling include: temperature 10-25°C.

[0068] The second aspect of the present application provides a system for separating fusel oil in a fermentation process for producing ethanol, which comprises:

[0069] a mixing unit connected by pipelines with the rough auxiliary column and / or the evaporation unit, and connected by pipelines with the rectification column, for mixing the rough auxiliary column bottom liquid from the rough auxiliary column and / or the evaporation condensate from the evaporation unit with the rectification column impurities from the rectification column;

[0070] a cooling unit connected by pipelines with the mixing unit, for cooling the mixed liquid from the mixing unit;

[0071] a fusel oil separation unit connected by pipelines with the cooling unit, for separating the material from the cooling unit to obtain fusel oil and light wine.

[0072] It should be understood that, depending on the raw material for the fermentation process for producing ethanol, the system for the fermentation process for producing ethanol can comprise different units, for example, when the raw material is starch raw material, the system for the fermentation process for producing ethanol can comprise:

[0073] a crushing unit for crushing the starch raw material to obtain a crushed product;

[0074] a slurry preparation unit for preparing a starch slurry from the crushed product;

[0075] a liquefaction unit for enzymatically hydrolyzing the starch slurry to obtain a liquefied liquid;

[0076] a fermentation unit for fermenting the liquefied liquid to obtain a matured mash;

[0077] a crude distillation unit for distilling the matured mash to obtain a crude distillation fraction, a waste mash and a crude auxiliary column still pot liquid;

[0078] a rectification unit for rectifying the crude distillation fraction to obtain a rectification column fusel oil and ethanol;

[0079] a separation unit for separating the waste mash to obtain a waste mash wet cake and a clear liquid;

[0080] an evaporation unit for evaporating and concentrating the clear liquid to obtain a syrup and an evaporation condensate.

[0081] For example, when the raw material is a cellulose raw material, the ethanol fermentation system can comprise:

[0082] a crushing unit for crushing the cellulose raw material to obtain a crushed product;

[0083] a pretreatment unit for pretreating the crushed product to obtain a pretreated material;

[0084] an enzymolysis unit for enzymolysing the pretreated material to obtain an enzymolysis liquid;

[0085] a fermentation unit for fermenting the enzymolysis liquid to obtain a matured mash;

[0086] a crude distillation unit for distilling the matured mash to obtain a crude distillation fraction, a waste mash and a crude auxiliary column still pot liquid;

[0087] a rectification unit for rectifying the crude distillation fraction to obtain a rectification column fusel oil and ethanol;

[0088] a separation unit for separating the waste mash to obtain a waste mash wet cake and a clear liquid;

[0089] an evaporation unit for evaporating and concentrating the clear liquid to obtain a syrup and an evaporation condensate.

[0090] The crude distillation unit can comprise a crude distillation column and a crude auxiliary column.

[0091] The functions or purposes of the units or devices involved in the system for separating fusel oil in the ethanol fermentation process are known in the art and will not be described here.

[0092] The mixing unit can comprise a mixing device, which can be a reactor with stirring or other pipes or devices capable of mixing, such as a Venturi converging pipe.

[0093] Preferably, the mixing unit comprises a Venturi converging pipe for mixing the crude auxiliary column tower bottom liquid from the crude auxiliary column and / or the evaporation condensate from the evaporation unit and optional process water with the rectifier column wine from the rectifier column.

[0094] Preferably, the mixing unit further comprises a heating device for heating the mixed liquid.

[0095] The cooling unit can comprise a device capable of cooling the mixed liquid, which can be a heat exchanger.

[0096] Preferably, the fusel oil separation unit comprises a fusel oil separator.

[0097] Preferably, the system further comprises a process water supply unit connected to the mixing unit by a pipeline for providing process water to mix with the rectifier column wine.

[0098] Preferably, the system further comprises a recovery column connected to the fusel oil separation unit by a pipeline for evaporating the light wine to obtain recovery column wine and industrial wine.

[0099] Preferably, the recovery column is connected to the mixing system by a pipeline for returning the recovery column wine to the mixing unit to separate together with the rectifier column wine to obtain fusel oil and light wine.

[0100] In the present application, unless otherwise specified, the devices and apparatus used are conventional devices and apparatus in the art, which can be selected by those skilled in the art as needed, and the connection modes are not particularly limited, which can be determined by those skilled in the art as needed.

[0101] The third aspect of the present application provides the use of the system as described above in the separation of fusel oil in the fermentation process for producing ethanol.

[0102] The present application will be described in detail below through examples.

[0103] In the following examples, unless otherwise specified, the devices and materials used are conventional devices and materials; the operating conditions are conventional operating conditions in the art.

[0104] In the following examples, the material containing fusel oil comprises rectifier column wine and recovery column wine.

[0105] The content of fusel oil can be determined by gas chromatography, and the total content of n-propanol, isobutanol and isoamyl alcohol is taken as the standard.

[0106] Preparation Example 1

[0107] The present preparation example is used to illustrate the method for preparing rectifier column wine from matured mash.

[0108] The matured fermentation broth prepared by fermenting corn as raw material is transported to a rough distillation column for rough distillation, and the wine liquid taken from the middle part of the rough distillation column is transported into a rough auxiliary column for concentration, the concentrated wine vapor is returned to the middle part of the rough distillation column, and the concentrated waste water without alcohol is discharged from the bottom of the rough auxiliary column, which is the rough auxiliary column liquid; the material discharged from the bottom of the rough distillation column is waste broth.

[0109] The working conditions of the rough distillation column include that the bottom temperature is 80.5-83℃, the bottom pressure is -0.035MPa to -0.04MPa, the top temperature is 60-61℃, and the top pressure is -0.06MPa to -0.063MPa. The working conditions of the rough auxiliary column include that the bottom temperature is 75-78℃, the bottom pressure is -0.01MPa to -0.015MPa, the top temperature is 62.5-64℃, and the top pressure is -0.03MPa to -0.035MPa. The temperature of the obtained rough auxiliary column liquid is about 75℃, and the pH is about 3.86.

[0110] The waste broth is subjected to centrifugation and evaporation treatment to obtain evaporation condensate, wherein the temperature of the evaporation condensate is about 65℃, and the pH is about 3.59.

[0111] The rough distillation fraction is transported to a rectification column through a water washing tower for rectification, and the rectification column miscellaneous wine is taken out at the fusel oil taking-out port of the rectification column, wherein the working conditions of the rectification column include that the bottom temperature is 130-135℃, the bottom pressure is 0.21-0.23MPa, the top temperature is 105-108℃, and the top pressure is 0.17-0.18MPa. The taking-out temperature of the rectification column miscellaneous wine is 107-112℃, the content of ethanol is 70-75vol%, and the content of fusel oil is 12-15vol%.

[0112] Example 1

[0113] This example is used to illustrate the system and method for separating fusel oil in the fermentation process for producing ethanol according to the present application.

[0114] (1) The step of separating fusel oil in the fermentation process for producing ethanol is carried out in the following system, which comprises:

[0115] A mixing unit is connected with the rough auxiliary column and / or the evaporation unit through pipelines, and is connected with the rectification column through a pipeline, and is used for mixing the rough auxiliary column liquid from the rough auxiliary column and / or the evaporation condensate from the evaporation unit with the miscellaneous wine from the rectification column and the recovery column;

[0116] A cooling unit is connected with the mixing unit through a pipeline, and is used for cooling the mixed liquid from the mixing unit;

[0117] A fusel oil separation unit is connected with the cooling unit through a pipeline, and is used for separating the material from the cooling unit to obtain fusel oil and light wine;

[0118] a recovery column connected with the fusel oil separation unit through a pipeline, for evaporating the light wine to obtain recovery column light wine and industrial wine; the recovery column is connected with the mixing system through a pipeline, for returning the recovery column light wine to the mixing unit to separate together with the rectifier column light wine to obtain fusel oil and light wine;

[0119] a process water supply unit connected with the mixing unit through a pipeline, for providing process water to mix with the light wine (including the rectifier column light wine and the recovery column light wine).

[0120] The mixing unit comprises a Venturi converging pipe for mixing the crude auxiliary column bottom liquid from the crude auxiliary column and / or the evaporation condensate from the evaporation unit and optional process water with the light wine from the rectifier column and the recovery column. The mixing unit further comprises a heating device for heating the mixed liquid.

[0121] The cooling unit comprises a heat exchanger, and the fusel oil separation unit comprises a fusel oil separator.

[0122] (2) The method for separating fusel oil in the fermentation process for producing ethanol comprises the following steps:

[0123] The evaporation condensate prepared in Preparation Example 1 is mixed with the material containing fusel oil in a Venturi converging pipe at a volume ratio of 3:1, and the pH of the obtained mixed liquid is 3.8-4.0, the temperature is 75-78℃, and the ethanol content is 13-15% by volume.

[0124] The mixed liquid is transported to a heat exchanger to be cooled to 25℃, and then the cooled material is transported to a fusel oil separator to be separated to obtain light wine and fusel oil. The light wine is treated by a recovery column to obtain industrial wine. The light wine is distilled in the recovery column to obtain recovery column light wine and industrial wine, and the recovery column light wine is transported to the Venturi converging pipe as the material containing fusel oil to be mixed. The working conditions of the recovery column include that the bottom temperature is 108-110℃, the bottom pressure is 0.045-0.055 MPa, the top temperature is 79-81℃, and the top pressure is 0.015-0.02 MPa.

[0125] After running for 12 months, no scaling phenomenon occurs on the light wine tank outlet pump impeller and the recovery column tray surface; the pressure of the recovery column is normal, and the flow of alcohol vapor is stable.

[0126] The fusel oil yield is 2.48‰, the fusel oil content of the light wine is 0.85% (mass / volume), and the fusel oil is colorless.

[0127] Example 2

[0128] This example is used to illustrate the method for separating fusel oil in the fermentation process for producing ethanol according to the present application.

[0129] The isolation of fusel oil was carried out in the system described in Example 1, except that an equal volume of the crude auxiliary column kettle liquid prepared in Preparation Example 1 was used to replace the evaporation condensate, and the pH of the obtained mixed liquid was 4.0-4.3.

[0130] After running for 12 months, no scaling phenomenon occurred on the outlet pump impeller of the light wine tank and the surface of the tray of the recovery column; the pressure of the recovery column was normal, and the alcohol vapor flow was stable.

[0131] The yield of fusel oil was 2.35‰, the fusel oil content of the light wine was 1.03% (mass / volume), and the fusel oil was light yellow.

[0132] Example 3

[0133] This example is used to illustrate the method for isolating fusel oil in the fermentation process for producing ethanol according to the present application.

[0134] The isolation of fusel oil was carried out in the system described in Example 1, except that an equal volume of the mixture of evaporation condensate and deep well water was used to replace the evaporation condensate, and the pH of the obtained mixed liquid was controlled to be 4.8-5.1.

[0135] After running for 12 months, slight scaling phenomenon occurred on the outlet pump impeller of the light wine tank and the surface of the tray of the recovery column, the pressure at the bottom of the recovery column began to rise, and the alcohol vapor flow slightly decreased.

[0136] The yield of fusel oil was 2.30‰, the fusel oil content of the light wine was 1.02% (mass / volume), and the fusel oil was colorless.

[0137] Example 4

[0138] This example is used to illustrate the method for isolating fusel oil in the fermentation process for producing ethanol according to the present application.

[0139] The isolation of fusel oil was carried out in the system described in Example 1, except that the temperature of the mixed liquid was 90°C.

[0140] After running for 12 months, no scaling phenomenon occurred on the outlet pump impeller of the light wine tank and the surface of the tray of the recovery column; the pressure of the recovery column was normal, and the alcohol vapor flow was stable.

[0141] The yield of fusel oil was 2.58‰, the fusel oil content of the light wine was 0.78% (mass / volume), and the fusel oil was colorless; since the fusel wine needed to be heated and cooled before the isolation of fusel oil, the power consumption was high.

[0142] Comparative Example 1

[0143] This comparative example is used to illustrate a method for isolating fusel oil in the fermentation process for producing ethanol according to the prior art.

[0144] The isolation of fusel oil was carried out in the system described in Example 1, except that an equal volume of deep well water was used instead of the evaporated condensate, and the pH of the resulting mixture was 7-7.3 and the temperature of the mixture was 75-78°C.

[0145] The yield of fusel oil was 2.08‰, the fusel oil content of the light wine was 1.38% (mass / volume), and the fusel oil was colorless.

[0146] After 30 days of operation, the surface of the impeller of the outlet pump of the light wine tank was fouled, the trays of the recovery column were fouled, the pressure at the bottom of the recovery column increased significantly, and the flow of alcohol vapor decreased.

[0147] Comparative Example 2

[0148] This comparative example is used to illustrate a method for isolating fusel oil in a reference fermentation process for producing ethanol.

[0149] The isolation of fusel oil was carried out in the system described in Example 1, except that an equal volume of a dilute sulfuric acid solution (a certain proportion of sulfuric acid mixed in process water) was used instead of the evaporated condensate, and the pH of the resulting mixture was 3.8-4.0 and the temperature of the mixture was 75-78°C.

[0150] The yield of fusel oil was 2.33‰, the fusel oil content of the light wine was 1.09% (mass / volume), and the fusel oil was colorless.

[0151] After 45 days of operation, the surface of the impeller of the outlet pump of the light wine tank was fouled, and the trays of the recovery column were fouled; after 70 days of operation, the pressure at the bottom of the recovery column increased significantly, and the flow of alcohol vapor decreased.

[0152] The above describes preferred embodiments of the present application, but the present application is not limited thereto. Within the technical concept of the present application, various simple modifications can be made to the technical solutions of the present application, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be considered as disclosed by the present application and fall within the protection scope of the present application.

Claims

1. A method for separating fusel oil in an ethanol production by fermentation, characterized by, The method comprises: (1) subjecting matured mash to crude distillation in a crude distillation column and a crude auxiliary column to obtain waste mash, crude auxiliary column bottom liquid and crude distillation fraction; (2) subjecting the waste mash obtained in step (1) to solid-liquid separation to obtain clear liquid; and subjecting the clear liquid to evaporation and concentration to obtain evaporation condensate; (3) subjecting the crude distillation fraction to rectification to obtain rectification column miscellaneous wine and ethanol; (4) subjecting the rectification column miscellaneous wine to separation to obtain fusel oil and light wine; In step (4), the separation mode comprises: sequentially mixing, cooling and fusel oil separation of the crude auxiliary column bottom liquid obtained in step (1) and / or the evaporation condensate obtained in step (2) with the rectification column miscellaneous wine and optional process water to obtain fusel oil and light wine; In step (4), the amounts of the crude auxiliary column bottom liquid, the evaporation condensate and the process water are such that the ethanol content in the mixed liquid is 5-15% by volume, and the pH of the mixed liquid is 3.5-5.5, and the mixing conditions comprise: temperature of 50-100℃.

2. The method of claim 1, wherein, The temperature of the crude auxiliary column bottom liquid is 75-85℃, and the pH is 3-4.5; and / or The temperature of the evaporation condensate is 50-75℃, and the pH is 3-4.

5.

3. The method of claim 1 or 2, wherein, The mixing conditions comprise: temperature of 60-85℃; The cooling conditions comprise: temperature of 4-30℃.

4. The method of claim 3, wherein, The cooling conditions comprise: temperature of 10-25℃.

5. The method of claim 1, wherein, The mixing is carried out in a Venturi convergent pipe; and / or The fusel oil separation is carried out in a fusel oil separator.

6. The method of claim 1, wherein, The method further comprises: subjecting the light wine obtained in step (4) to distillation in a recovery column to obtain recovery column miscellaneous wine and industrial wine; The recovery column miscellaneous wine is refluxed to step (4) to be separated together with the rectification column miscellaneous wine to obtain fusel oil and light wine.

7. A system for a method of separating fusel oils in an ethanol fermentation process according to any one of claims 1 to 6, characterized in that, The system comprises: a mixing unit connected by pipelines with the crude auxiliary column and / or the evaporation unit, and connected by pipelines with the rectification column, for mixing the crude auxiliary column bottom liquid from the crude auxiliary column and / or the evaporation condensate from the evaporation unit with the rectification column miscellaneous wine from the rectification column; a cooling unit connected by pipelines with the mixing unit, for cooling the mixed liquid from the mixing unit; a fusel oil separation unit connected by pipelines with the cooling unit, for separating the material from the cooling unit to obtain fusel oil and light wine.

8. The system of claim 7, wherein, The system further comprises a recovery column connected by pipelines with the fusel oil separation unit, for subjecting the light wine to evaporation to obtain recovery column miscellaneous wine and industrial wine.

9. The system of claim 8, wherein, The recovery column is connected by pipelines with the mixing system, for refluxing the recovery column miscellaneous wine to the mixing unit to be separated together with the rectification column miscellaneous wine to obtain fusel oil and light wine.

10. The system of claim 7, wherein, The mixing unit comprises a Venturi convergent pipe; and / or The fusel oil separation comprises a fusel oil separator.

11. Use of the system of any one of claims 7-10 in the separation of fusel oil in a fermentation process for producing ethanol.

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