CN106928026B - Method for distilling cellulosic ethanol - Google Patents
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Abstract
The invention relates to the field of cellulose ethanol purification, and discloses a cellulose ethanol distillation method, which comprises the following steps: feeding the heated fermented liquor into a first distillation tower for distillation, collecting first ethanol steam at the tower top, collecting a first ethanol mixture at the side line of the first distillation tower, condensing the first ethanol steam collected at the tower top to form ethanol condensate, refluxing part of the ethanol condensate, and feeding the other part of the ethanol condensate into a third distillation tower for distillation; feeding the first ethanol mixture extracted from the side line of the first distillation tower into a second distillation tower for distillation; and (3) extracting second ethanol steam from the top of the second distillation tower, feeding part of the second ethanol steam into a third distillation tower for distillation, and dehydrating the other part of the second ethanol steam. The method provided by the invention can effectively recover the cellulosic ethanol from the fermented mash of the cellulosic ethanol with high purity and high yield.
Description
Technical Field
The invention relates to the field of cellulose ethanol purification, in particular to a cellulose ethanol distillation method.
Background
Energy and environmental issues are issues that must be addressed to achieve sustainable development. The shortage of liquid fuel will be a big problem that plagues human development in the long run. In this context, biomass is gaining increasing attention as the only renewable resource that can be converted to liquid fuels. Therefore, the technology of preparing liquid fuel from biomass has a great development prospect, and the technology of preparing fuel ethanol from biomass is attracting attention. The existing industrial fuel ethanol production uses sugar or grain as raw materials, and has the advantages of mature process, but the yield is limited by the raw materials and is difficult to meet the energy requirement for a long time.
In the long run, the production of fuel ethanol by using cellulosic biomass (including crop straws, forestry processing waste, bagasse, municipal refuse and the like) as a raw material may be one of the main approaches for solving the source of the raw material and carrying out large-scale production. The Chinese has favorable conditions for developing cellulose to prepare ethanol, only crop straws have more than 7 hundred million tons (dry weight) every year, and the food resources in China are not abundant, so the method converts agricultural and forestry wastes into fuel ethanol, forms industrialized utilization, is very suitable for national conditions in China, is very favorable from the aspect of energy safety, and can eliminate the environmental problem caused by burning the straws.
The production of the cellulosic ethanol comprises the steps of firstly processing raw materials into sugar liquid suitable for fermentation, and then fermenting to obtain fermented mash. The fermented mash is a complex multigroup mixture containing water, solids, ethanol, and volatile and non-volatile impurities mixed therein. Wherein, ethanol is a key component. The solids in the beer are classified into insoluble solids and soluble solids. Insoluble matter (also known as suspended matter TSS) generally includes: yeast, husk, insoluble starch and a large amount of lignin and other impurities; soluble impurities all unfermented sugars, dextrins, soluble proteins, inorganic salts and the like, and in addition, glycerol, lactic acid and the like are non-volatile impurities.
Traditional ethanol distillation processes are mainly aimed at corn ethanol or cassava ethanol, but are rarely aimed at cellulosic ethanol, such as ethanol produced from corn stalks, because the components of the fermented mash formed from different raw materials are very different. Taking the ethanol content as an example, the ethanol concentration in the corn fermentation mash is 10-13 vol%, the ethanol concentration in the cassava fermentation mash is 10-13 vol%, and the ethanol concentration in the corn straw fermentation mash is lower, about 5 vol%. Secondly, the concentration of total solid in the fermented mash is different, the content of the total solid in the straw fermented mash is 10-13% at the highest, and the concentration of the total solid in the corn and cassava starch fuel ethanol fermented mash is 8-9% and 6-8% respectively. In addition, the concentration of sulfate ions in the corn straw fermentation mash is higher, and the other two fermentation mash basically have no sulfate ions; in contrast, the methanol content in the corn stalk fermented mash is much lower than that of the other two types, and is only 0.01-0.02%.
Because the components of the fermented mash formed by different raw materials have larger difference, the traditional ethanol distillation process aiming at corn ethanol or cassava ethanol is not suitable for cellulosic ethanol, and therefore, the development of a method suitable for distilling cellulosic ethanol is very necessary.
Disclosure of Invention
The purpose of the present invention is to provide a method for distilling cellulosic ethanol, by which cellulosic ethanol can be efficiently recovered from a fermentation mash of cellulosic ethanol with high purity and high yield.
The method for distilling the cellulosic ethanol comprises the following steps: feeding the heated fermented liquor into a first distillation tower for distillation, collecting first ethanol steam at the tower top, collecting a first ethanol mixture at the side line of the first distillation tower, condensing the first ethanol steam collected at the tower top to form ethanol condensate, refluxing part of the ethanol condensate, and feeding the other part of the ethanol condensate into a third distillation tower for distillation; feeding the first ethanol mixture extracted from the side line of the first distillation tower into a second distillation tower for distillation; extracting second ethanol steam from the top of the second distillation tower, feeding part of the second ethanol steam into a third distillation tower for distillation, and dehydrating the other part of the second ethanol steam;
wherein the distillation conditions of the first distillation column (1) comprise: the number of the tower plates is 14-18, the temperature at the top of the tower is 60-70 ℃, the pressure at the top of the tower is-0.05 to-0.03 MPa, the temperature at the bottom of the tower is 80-95 ℃, and the pressure at the bottom of the tower is-0.06 to-0.045 MPa;
the distillation conditions of the second distillation column (2) include: the number of tower plates is 36-40, the temperature at the top of the tower is 90-98 ℃, the pressure at the top of the tower is 0.08-0.095 Mpa, the temperature at the bottom of the tower is 120-128 ℃, and the pressure at the bottom of the tower is 0.122-0.13 Mpa;
the distillation conditions of the third distillation column (3) include: the number of the tower plates is 38-42, the temperature at the top of the tower is 132-138 ℃, the pressure at the top of the tower is 0.5-0.65 MPa, the temperature at the bottom of the tower is 162-168 ℃, and the pressure at the bottom of the tower is 0.59-0.6 MPa.
The invention provides a method for distilling cellulosic ethanol, and aims at an ethanol mixture of the cellulosic ethanol fermented from a specific raw material, the inventor designs a set of efficient and reasonable method for distilling the cellulosic ethanol. In addition, the waste residue of the cellulosic ethanol can be utilized after being separated and dried.
Additional features and advantages of the invention will be set forth in the detailed description which follows.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention. In the drawings:
FIG. 1 is a schematic flow diagram of a cellulosic ethanol distillation process provided by the present invention.
Description of the reference numerals
1 first distillation column 2 second distillation column
3 third distillation column 4 fusel extraction column
5 molecular sieve adsorption tower 6 feeding heat exchanger
7 first distillation column reboiler 8 second distillation column reboiler
9 first distillation column condenser 10 product cooler
12 molecular sieve tower feeding preheater of 11 solid-liquid separation equipment
A fermented mash B first cooling water
C uncondensed gas D second cooling water
E finished product ethanol condensate F heat exchange steam
G solid-phase material H filtrate
I fusel by-product J Wash Water
K light wine L returns substances recovered by enzymolysis
Detailed Description
The following describes in detail specific embodiments of the present invention. It should be understood that the detailed description and specific examples, while indicating the present invention, are given by way of illustration and explanation only, not limitation.
The invention provides a method for distilling cellulose ethanol, which comprises the following steps:
feeding the heated fermented liquor into a first distillation tower 1 for distillation, collecting first ethanol steam at the top of the tower, collecting a first ethanol mixture at the lateral line of the first distillation tower 1, condensing the first ethanol steam collected at the top of the tower to form ethanol condensate, refluxing part of the ethanol condensate, and feeding the other part of the ethanol condensate into a third distillation tower 3 for distillation; feeding the first ethanol mixture which is extracted from the side line of the first distillation tower 1 into a second distillation tower 2 for distillation; a second ethanol steam is extracted from the top of the second distillation tower 2, part of the second ethanol steam is sent to a third distillation tower 3 for distillation, and the other part of the second ethanol steam is dehydrated;
wherein the distillation conditions of the first distillation column (1) comprise: the number of the tower plates is 14-18, the temperature at the top of the tower is 60-70 ℃, the pressure at the top of the tower is-0.05 to-0.03 MPa, the temperature at the bottom of the tower is 80-95 ℃, and the pressure at the bottom of the tower is-0.06 to-0.045 MPa;
the distillation conditions of the second distillation column (2) include: the number of tower plates is 36-40, the temperature at the top of the tower is 90-98 ℃, the pressure at the top of the tower is 0.08-0.095 Mpa, the temperature at the bottom of the tower is 120-128 ℃, and the pressure at the bottom of the tower is 0.122-0.13 Mpa;
the distillation conditions of the third distillation column (3) include: the number of the tower plates is 38-42, the temperature at the top of the tower is 132-138 ℃, the pressure at the top of the tower is 0.5-0.65 MPa, the temperature at the bottom of the tower is 162-168 ℃, and the pressure at the bottom of the tower is 0.59-0.6 MPa.
In the present invention, all pressures are gauge pressures. Wherein "-" represents a negative pressure, for example, -0.05MPa represents a negative pressure of 0.05 MPa.
In the present invention, the meaning of cellulosic ethanol is well known to those skilled in the art, and generally, cellulosic ethanol is feedstock ethanol produced from cellulosic biomass as a feedstock, which may include cellulose, hemicellulose and lignin.
In the invention, the fermented mash can be prepared by the corn straw through the processes of pretreatment, enzymolysis and fermentation.
In the present invention, the kinds of the first distillation column 1, the second distillation column 2 and the third distillation column 3 may be the same or different, and are all conventional choices in the art, for example, the first distillation column 1 may be a crude column; the second distillation column 2 may be a rectification column; the third distillation column 3 may be a rectification column.
In the present invention, the counting direction of the tray positions is from top to bottom. For example, a feed tray position of 2 refers to tray 2 from the top of the column.
In FIG. 1 of the present invention, the positions are merely referred to, and the specific positions are determined by the positions of the number of plates.
According to the invention, the method may further comprise withdrawing a bottom material from the bottom of the first distillation column 1 and subjecting the bottom material to heat exchange with the fermented mash in a feed heat exchanger 6 to obtain said heated fermented mash.
In the present invention, the conditions under which the beer exchanges heat with the bottoms material in the feed heat exchanger 6 are conventional in the art, e.g., the temperature of the beer prior to heat exchange may be 20-40 ℃ and the temperature of the heated beer may be 60-75 ℃.
According to the invention, the heated fermented liquor enters the first distillation tower 1, and is subjected to mass transfer with steam rising in a tower kettle on a tower tray of the first distillation tower 1 to form a mass-transferred mixture, and first ethanol steam formed by evaporation of ethanol in the mixture moves to the top of the first distillation tower 1 due to different relative volatilities of the ethanol and water and is discharged from the top of the first distillation tower 1. Wherein, the position of the tower plate for the heated fermented liquor to enter the first distillation tower 1 is 2-3.
According to a preferred embodiment of the present invention, the distillation conditions of the first distillation column 1 include: the number of the tower plates is 16-18, the temperature at the top of the tower is 63-65 ℃, the pressure at the top of the tower is-0.045 to-0.04 Mpa, the temperature at the bottom of the tower is 83-85 ℃, and the pressure at the bottom of the tower is-0.055 to-0.05 Mpa.
More preferably, the distillation conditions of the first distillation column 1 include: the number of the tower plates is 16-18, the tower plates are in the form of float valves, the efficiency of the tower plates is 45-55%, the space between the tower plates is 0.5-0.6 m, and the reflux ratio is 1.8-2.
In the present invention, the content of ethanol in the first ethanol vapor may be 35 to 40% by weight.
In the present invention, the first ethanol vapor is passed through the first distillation column condenser 9 to form an ethanol condensate, and the condensation conditions may be selected as conventional in the art, for example, the condensation temperature may be 60-75 ℃. Refluxing a part of ethanol condensate, and sending the other part of ethanol condensate into a third distillation tower 3 for distillation; the ethanol condensate refluxed may be 35 to 40 wt% and the ethanol condensate distilled in the third distillation column 3 may be 60 to 65 wt% based on the total weight of the ethanol condensate formed by condensing the first ethanol vapor.
In the present invention, the method further comprises introducing uncondensed gas into a vacuum system and discharging bottom waste liquid of the first distillation column 1 from the bottom of the first distillation column 1. Wherein, after the first ethanol vapor is condensed by the first distillation tower condenser 9, part of the gas is not condensed, the uncondensed gas mainly comprises carbon dioxide and part of the first ethanol vapor carried by the carbon dioxide, and the uncondensed gas enters a vacuum system. The post-treatment process of the waste liquid at the bottom of the first distillation tower 1 is well known to those skilled in the art, for example, the waste liquid is sent to a solid-liquid separation device 11 for filtration, the filtered solid-phase material is sent to a drying unit, and the filtrate is sent to a sewage treatment system, and specific conditions are not described again. The content of ethanol in the tower bottom waste liquid of the first distillation tower 1 is not more than 0.04 wt%.
In the present invention, the first ethanol mixture which is taken out from the first distillation column 1 side is fed to the second distillation column 2 to be distilled. Wherein, the tray position of the first ethanol mixture extraction can be 5-6, and the tray position of the first ethanol mixture entering the second distillation tower 2 can be 8-10. The ethanol content of the first ethanol mixture may be 8-10 wt%.
According to a preferred embodiment of the present invention, the distillation conditions of the second distillation column 2 include: the number of tower plates is 38-40, the temperature at the top of the tower is 94-96 ℃, the pressure at the top of the tower is 0.085-0.09 Mpa, the temperature at the bottom of the tower is 124-126 ℃, and the pressure at the bottom of the tower is 0.126-0.128 Mpa.
More preferably, the distillation conditions of the second distillation column 2 include: the number of the tower plates is 38-40, the tower plates are float valves, the efficiency of the tower plates is 65-70%, the distance between the tower plates is 0.5-0.52 m, and the reflux ratio is 1.8-2.
In the present invention, the first ethanol mixture entering the second distillation column 2 and the steam in the column form a second ethanol steam under the action of distillation, and the second ethanol steam is extracted from the top of the second distillation column 2, wherein part of the second ethanol steam is used as a heat source for a reboiler 7 of the first distillation column and then is sent to the third distillation column 3.
Wherein the conditions of the first distillation column reboiler 7 comprise: the temperature can be 90-130 deg.C, and the pressure can be 0.01-1 MPa.
In the present invention, the content of ethanol in the second ethanol vapor may be 90 to 95% by weight.
In the present invention, another part of the second ethanol vapor is dehydrated by a method comprising: and sending the other part of the second ethanol steam into a molecular sieve adsorption tower 5 for dehydration to obtain a finished product ethanol. Preferably, the second ethanol vapor entering the molecular sieve adsorption column 5 is preferentially heated by the molecular sieve column feed preheater 12 before entering the molecular sieve adsorption column. The conditions of the molecular sieve adsorption column include: the temperature can be 120 ℃ and 130 ℃, and the pressure can be 0.045-0.05 MPa. The finished product ethanol exists in a gas form, the finished product ethanol gas overflows from the upper part of the molecular sieve adsorption tower 5, is cooled by a product cooler 10 to form finished product ethanol condensate, and then enters a finished product tank.
According to a preferred embodiment of the present invention, the molecular sieve is regenerable for reuse. The conditions for regeneration are conventionally selected in the art, and for example, the temperature may be 80 to 120 ℃, the time may be 2 to 12 hours, and the pressure may be 0.01 to 0.1 MPa.
In the present invention, the weight ratio of a portion of the second ethanol vapor fed to the third distillation column 3 for distillation to another portion of the second ethanol vapor for dehydration may be 1.8 to 2.2: 1.
in the present invention, the method further comprises taking a second ethanol mixture from the side of the second distillation column 2 and feeding the second ethanol mixture together with the other part of the ethanol condensate to the third distillation column 3 for distillation. Wherein, the tray position of the second ethanol mixture extraction can be 8-10, and the tray position of the second ethanol mixture and the other part of ethanol condensate entering the third distillation tower 3 can be 20-25. The second ethanol mixture may have an ethanol content of 35 to 45 wt.%.
Wherein, according to a preferred embodiment of the present invention, the distillation conditions of the third distillation column 3 include: the number of the tower plates is 40-42, the temperature at the top of the tower is 134-136 ℃, the pressure at the top of the tower is 0.55-0.6MPa, the temperature at the bottom of the tower is 164-166 ℃, and the pressure at the bottom of the tower is 0.594-0.596 MPa.
More preferably, the distillation conditions of the third distillation column 3 include: the number of the tower plates is 40-41, the tower plates are float valves, the efficiency of the tower plates is 70-72%, the distance between the tower plates is 0.6-0.7 m, and the reflux ratio is 6-8.
In the present invention, the method further comprises condensing the third ethanol vapor taken out from the top of the third distillation column 3 as a heat source of the reboiler 8 of the second distillation column, and feeding the condensed vapor to the second distillation column 2 for distillation. Wherein the reboiling conditions of the second distillation column reboiler 8 comprise: the temperature can be 80-120 deg.C, and the pressure can be 0.01-1 MPa.
According to the present invention, the content of ethanol in the third ethanol vapor may be 50 to 60% by weight.
According to the invention, the method further comprises: the fusel oil-containing mixture is extracted from the third distillation tower 3, wherein the fusel oil-containing mixture can contain fusel oil, ethanol and water. Wherein the content of ethanol in the fusel oil-containing mixture can be 1.8-2 wt%. The withdrawn tray position may be 18 to 20. The extracted mixture enters a fusel extraction tower 4, and the position of the extracted mixture entering the fusel extraction tower 4 is 4-6. The weak liquor produced in the fusel extraction tower 4 is returned to the first distillation tower 1 for recovery. The fusel byproduct is extracted from the top of the fusel extraction tower 4, and the substance returned to enzymolysis recovery is extracted from the bottom of the fusel extraction tower 4.
In the present invention, the first distillation column 1 is provided with a first distillation column reboiler 7, and the second distillation column 2 is provided with a second distillation column reboiler 8, and except for the foregoing description of the first distillation column reboiler 7 and the second distillation column reboiler 8, the other conditions are conventional in the art and will not be described herein again.
The present invention will be described in detail below by way of examples.
In the examples, the purity of the ethanol in the finished tank was measured by a gas chromatography instrument (agilent, model 7890B); the ethanol recovery rate refers to the ratio of the weight of the ethanol obtained by the fermentation mash with fixed amount through the method of the invention to a theoretical value, and the specific calculation method is as follows: the recovery rate of ethanol is the weight of ethanol in the finished product tank/weight of ethanol in cellulosic ethanol × 100%.
Example 1
This example serves to illustrate the process for the distillation of cellulosic ethanol provided by the present invention.
In this embodiment, the fermented mash is obtained by performing pretreatment, enzymolysis and fermentation on corn stalks, and the fermented mash contains the following components: 5.4 percent of ethanol, 76.6 percent of water, 1.55 percent of acids, 2.9 percent of residual sugar, 13 percent of solid matters and 0.75 percent of glycerol. This example was carried out in the apparatus shown in FIG. 1.
As shown in FIG. 1, the fermented mash A is heat exchanged with the material extracted from the bottom of the first distillation column 1 in the feed heat exchanger 6 to obtain a heated fermented mash, the temperature of the fermented mash before heat exchange is 30 ℃ and the temperature of the heated fermented mash is 63 ℃. The heated fermented mash enters the first distillation column 1. And (3) the heated fermented liquor and the steam rising in the tower kettle are subjected to mass transfer on a tower tray of the first distillation tower 1 to form a mass-transferred mixture, the first ethanol steam formed by evaporation of ethanol in the mixture moves towards the top of the first distillation tower 1, and the first ethanol steam is discharged from the top of the first distillation tower 1. The first ethanol steam is condensed by a first distillation tower condenser 9 to form ethanol condensate, and the first cooling water B passes through the first distillation tower condenser 9, wherein the condensation temperature is 60 ℃. Part of the ethanol condensate is refluxed, and the other part of the ethanol condensate is sent to a third distillation tower 3 for distillation. And taking the total weight of the ethanol condensate formed by condensing the first ethanol steam as a reference, the ethanol condensate refluxed is 35 wt%, and the ethanol condensate entering the third distillation tower 3 for distillation is 65 wt%. After the first ethanol vapor is condensed by the first distillation tower condenser 9, part of gas is not condensed, and the uncondensed gas C enters a vacuum system. And (3) filtering the tower bottom waste liquid of the first distillation tower 1 to solid-liquid separation equipment 11, removing the filtered solid-phase material G to a drying unit, and removing the filtrate H to a sewage treatment system.
A first ethanol mixture which is extracted from the side of the first distillation tower 1 and has an ethanol content of 8 wt% is fed to the second distillation tower 2 for distillation. The first ethanol mixture entering the second distillation column 2 forms a second ethanol steam under the action of the steam, and the second ethanol steam is extracted from the top of the second distillation column 2, wherein part of the second ethanol steam is used as a heat source for a first distillation column reboiler 7 and then enters the third distillation column 3. Heating the other part of the second ethanol steam by a molecular sieve tower feeding preheater 12, then dehydrating the second ethanol steam in a molecular sieve adsorption tower 5 to form finished product ethanol gas which overflows from the top of the molecular sieve adsorption tower 5, forming finished product ethanol condensate E by the finished product ethanol gas under the cooling of a product cooler 10, then feeding the finished product ethanol condensate E into a finished product tank, allowing the second cooling water D to pass through the product cooler 10, and allowing the heat exchange steam F to pass through the molecular sieve tower feeding preheater 12. The weight ratio of a part of the second ethanol vapor fed to the third distillation column 3 for distillation to the other part of the second ethanol vapor subjected to dehydration is 2: 1. a second ethanol mixture is taken off at the side of the second distillation column 2 and is fed to the third distillation column 3 together with the further portion of the ethanol condensate for distillation. The ethanol content of the second ethanol mixture was 40 wt.%. The third ethanol vapor overflowing from the top of the third distillation column 3 is used as a heat source of a reboiler 8 of the second distillation column, and is condensed to be used as reflux of the second distillation column 2. The fusel oil-containing mixture is withdrawn from the third distillation column 3 at a point 5 where the withdrawn mixture enters the fusel column 4. The weak wine K produced in the fusel extraction tower 4 is recycled in the first distillation tower 1. Washing water J enters a fusel extraction tower 4, a fusel byproduct I is extracted from the top of the fusel extraction tower 4, and a substance L returned to enzymolysis recovery is extracted from the bottom of the fusel extraction tower 4.
Wherein the operating temperature of the molecular sieve adsorption tower is 125 ℃, and the pressure is 0.048 MPa.
The purity of the ethanol in the finished product tank is 97%, and the recovery rate of the ethanol is 90%.
The remaining process parameters are seen in table 1.
TABLE 1
| Item | A first distillation column | Second distillation column | Third distillation column |
| Number of trays/block | 16 | 38 | 40 |
| Tray form | Float valve | Float valve | Float valve |
| Column tray efficiency/%) | 50 | 65 | 70 |
| Feed tray position | 2 | 10 | 25 |
| Tray spacing/m | 0.6 | 0.5 | 0.6 |
| Reflux ratio (molar ratio) | 2 | 2 | 6 |
| Side-draw ethanol extraction tower plate position | 6 | 8 | 18 |
| Side-stream ethanol withdrawal concentration/%) | 8 | 40 | 2 |
| Overhead temperature/. degree.C | 63 | 95 | 135 |
| Column bottom temperature/. degree.C | 83 | 125 | 165 |
| Overhead pressure (gauge pressure)/MPa | -0.043 | 0.088 | 0.55 |
| Column bottom pressure (gauge pressure)/MPa | -0.053 | 0.128 | 0.595 |
| Concentration of ethanol at column top (% by weight) | 40 | 90 | 90 |
| Tower reactor BAlcohol concentration (% by weight) | 0.04 | 0.04 | 0.04 |
The results of the examples show that the method for distilling the cellulosic ethanol provided by the invention can effectively purify the cellulosic ethanol, and has high purity and high recovery efficiency.
The preferred embodiments of the present invention have been described in detail, however, the present invention is not limited to the specific details of the above embodiments, and various simple modifications may be made to the technical solution of the present invention within the technical idea of the present invention, and these simple modifications are within the protective scope of the present invention.
It should be noted that the various features described in the above embodiments may be combined in any suitable manner without departing from the scope of the invention. The invention is not described in detail in order to avoid unnecessary repetition.
In addition, any combination of the various embodiments of the present invention is also possible, and the same should be considered as the disclosure of the present invention as long as it does not depart from the spirit of the present invention.
Claims (15)
1. A method for cellulosic ethanol distillation, comprising the steps of: feeding the heated fermented liquor into a first distillation tower (1) for distillation, collecting first ethanol steam at the top of the tower, collecting a first ethanol mixture at the lateral line of the first distillation tower (1), condensing the first ethanol steam collected at the top of the tower to form ethanol condensate, refluxing part of the ethanol condensate, and feeding the other part of the ethanol condensate into a third distillation tower (3) for distillation; feeding the first ethanol mixture which is extracted at the side line of the first distillation tower (1) into a second distillation tower (2) for distillation; second ethanol steam is extracted from the top of the second distillation tower (2), part of the second ethanol steam is sent to a third distillation tower (3) for distillation, and the other part of the second ethanol steam is dehydrated;
wherein the distillation conditions of the first distillation column (1) comprise: the number of the tower plates is 14-18, the temperature at the top of the tower is 60-70 ℃, the pressure at the top of the tower is-0.05 to-0.03 MPa, the temperature at the bottom of the tower is 80-95 ℃, and the pressure at the bottom of the tower is-0.06 to-0.045 MPa;
the distillation conditions of the second distillation column (2) include: the number of tower plates is 36-40, the temperature at the top of the tower is 90-98 ℃, the pressure at the top of the tower is 0.08-0.095 Mpa, the temperature at the bottom of the tower is 120-128 ℃, and the pressure at the bottom of the tower is 0.122-0.13 Mpa;
the distillation conditions of the third distillation column (3) include: the number of the tower plates is 38-42, the temperature at the top of the tower is 132-138 ℃, the pressure at the top of the tower is 0.5-0.65 MPa, the temperature at the bottom of the tower is 162-168 ℃, and the pressure at the bottom of the tower is 0.59-0.6 MPa;
the method also comprises taking a second ethanol mixture from the side line of the second distillation tower (2) and sending the second ethanol mixture and the other part of ethanol condensate into a third distillation tower (3) for distillation;
the method also comprises the steps of taking a third ethanol steam extracted from the top of the third distillation tower (3) as a heat source of a reboiler (8) of the second distillation tower, condensing the third ethanol steam and then feeding the condensed third ethanol steam into the second distillation tower (2) for distillation;
the mixture containing fusel oil is extracted from the third distillation tower (3), the extracted mixture enters a fusel extraction tower (4), and light wine produced by the fusel extraction tower (4) returns to the first distillation tower (1) for recycling.
2. The method according to claim 1, further comprising withdrawing a bottom material from the bottom of the first distillation column (1) and heat exchanging the bottom material with the fermented mash in a feed heat exchanger (6) to obtain said heated fermented mash.
3. The method according to claim 1, wherein the ethanol condensate refluxed is 35 to 40 wt% and the ethanol condensate distilled in the third distillation column (3) is 60 to 65 wt% based on the total weight of the ethanol condensate formed by condensing the first ethanol vapor.
4. The process according to claim 1, wherein the weight ratio of the portion of the second ethanol vapor fed to the third distillation column (3) for distillation to the other portion of the second ethanol vapor subjected to dehydration is from 1.8 to 2.2: 1.
5. the method of claim 1, wherein the first ethanol vapor comprises 35-40 wt% ethanol.
6. The method of claim 1, wherein the second ethanol vapor has an ethanol content of 90-95 wt.%.
7. The method of claim 4, wherein the step of dehydrating another portion of the second ethanol vapor comprises: and sending the other part of the second ethanol steam into a molecular sieve adsorption tower (5) for dehydration to obtain the finished product ethanol.
8. The method of claim 7, wherein the conditions of the molecular sieve adsorption column (5) comprise: the temperature is 120 ℃ and 130 ℃, and the pressure is 0.045 to 0.05 MPa.
9. The method of claim 1, wherein the third ethanol vapor has an ethanol content of 90-96 wt.%.
10. The method according to claim 1 or 4, wherein the method further comprises feeding the part of the second ethanol vapor fed to the third distillation column (3) for distillation as a heat source of the reboiler (7) of the first distillation column, and feeding the condensed part of the second ethanol vapor to the third distillation column (3) for distillation.
11. The process of claim 1, wherein the ethanol content of the first ethanol mixture is 8-10 wt.%.
12. The process of claim 1, wherein the second ethanol mixture has an ethanol content of 35-45% by weight.
13. The method according to claim 1, wherein the distillation conditions of the first distillation column (1) comprise: the number of the tower plates is 16-18, the temperature at the top of the tower is 63-65 ℃, the pressure at the top of the tower is-0.045 to-0.04 Mpa, the temperature at the bottom of the tower is 83-85 ℃, and the pressure at the bottom of the tower is-0.055 to-0.05 Mpa.
14. The method according to claim 1, wherein the distillation conditions of the second distillation column (2) comprise: the number of tower plates is 38-40, the temperature at the top of the tower is 94-96 ℃, the pressure at the top of the tower is 0.085-0.09 Mpa, the temperature at the bottom of the tower is 124-126 ℃, and the pressure at the bottom of the tower is 0.126-0.128 Mpa.
15. The method according to claim 1, wherein the distillation conditions of the third distillation column (3) comprise: the number of the tower plates is 40-42, the temperature at the top of the tower is 134-136 ℃, the pressure at the top of the tower is 0.55-0.6MPa, the temperature at the bottom of the tower is 164-166 ℃, and the pressure at the bottom of the tower is 0.594-0.596 MPa.
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| CN110204421B (en) * | 2019-07-17 | 2024-03-01 | 河南利诺生化有限责任公司 | Method and gradient recovery device for recovering ethanol from alpha-linolenic acid washing waste liquid |
| CN111187790B (en) * | 2020-04-09 | 2020-07-14 | 中粮营养健康研究院有限公司 | Method for preparing ethanol by using rice raw material |
| CN111714913B (en) * | 2020-07-31 | 2021-12-17 | 中国科学院上海应用物理研究所 | Rotary belt distillation device and method for separating ethanol in wine products |
| CN114685246B (en) * | 2020-12-29 | 2023-07-11 | 国投生物科技投资有限公司 | System and method for co-production of fuel ethanol and alcohol |
| CN114685245B (en) * | 2020-12-29 | 2023-07-07 | 国投生物科技投资有限公司 | System and method for co-production of fuel ethanol and high-grade wine |
| CN114685247B (en) * | 2020-12-29 | 2023-06-20 | 国投生物科技投资有限公司 | Method and system for co-producing fuel ethanol and edible alcohol |
| CN115636728B (en) * | 2021-07-20 | 2024-04-30 | 中国石油天然气股份有限公司 | Treatment method of cellulose ethanol fermentation mash and preparation method of cellulose fuel ethanol |
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