阅读说明：本技术 燃料乙醇蒸馏脱水装置和干酒糟蛋白饲料的制备方法 (Fuel ethanol distillation dehydration device and preparation method of dried distillers' grain protein feed ) 是由 林海龙 于斌 杜伟彦 刘劲松 熊强 于 2019-10-30 设计创作，主要内容包括：本发明涉及蒸馏脱水装置,具体涉及一种燃料乙醇蒸馏脱水装置和一种干酒糟蛋白饲料的制备方法,所述装置包括：依次连通的醪液预热装置、组合塔装置、精馏塔进料预热装置、精馏塔装置及分子筛装置；其中,所述组合塔装置包括组合塔(C401),在所述组合塔(C401)的底部设置连通热源的气相入口,用以向组合塔(C401)提供热量。本发明提供的装置充分利用了余热资源,减少新鲜蒸汽的用量,有效降低了装置能耗,又能够将废醪液控制在较低的温度,使负压塔的塔底醪液中美拉德反应发生的几率大幅下降,因此后续处理得到干酒糟蛋白饲料色泽和品质有显著改善。(The invention relates to a distillation dehydration device, in particular to a fuel ethanol distillation dehydration device and a preparation method of a distiller's dried grain protein feed, wherein the device comprises: the mash preheating device, the combined tower device, the rectifying tower feeding preheating device, the rectifying tower device and the molecular sieve device are sequentially communicated; the combined tower device comprises a combined tower (C401), wherein a gas phase inlet communicated with a heat source is arranged at the bottom of the combined tower (C401) and is used for providing heat for the combined tower (C401). The device provided by the invention fully utilizes waste heat resources, reduces the consumption of fresh steam, effectively reduces the energy consumption of the device, and can control the waste mash at a lower temperature, so that the probability of Maillard reaction in the mash at the bottom of the negative pressure tower is greatly reduced, and the color and the quality of the distiller's dried grain protein feed obtained by subsequent treatment are obviously improved.)

1. A fuel ethanol distillation dehydration apparatus, characterized in that the apparatus comprises: the mash preheating device, the combined tower device, the rectifying tower feeding preheating device, the rectifying tower device and the molecular sieve device are sequentially communicated;

the combined tower device comprises a combined tower (C401), wherein a gas phase inlet communicated with a heat source is arranged at the bottom of the combined tower (C401) and used for introducing a heat medium from the heat source into the combined tower (C401).

2. The distillation dewatering device according to claim 1, wherein the mash preheating device comprises a first cooler (E404) and a first (E401), a second (E402) and a third (E403) sequentially connected mash preheater;

wherein the mash primary preheater (E401) is further in communication with a mature mash feed tank and a combining column (C401) for heating the mature mash with steam from the top of the combining column (C401);

the first cooler (E404) is communicated with the mash primary preheater (E401), the combined tower (C401) and the vacuum system and is used for cooling at least part of reflux steam from the top of the mash primary preheater (E401) by using circulating water, the generated non-condensable gas is sent to the vacuum system, and the generated condensate is sent to the combined tower (C401);

the mash secondary preheater (E402) is also communicated with the rectifying tower feeding preheating device and the steam condensate receiving device and is used for heating the steam from the rectifying tower feeding preheating device to mature mash;

the mash tertiary preheater (E403) is also communicated with the combined tower (C401), the rectifying tower feeding preheating device and the waste water receiving device and is used for heating the waste liquid from the rectifying tower feeding preheating device to mature mash.

3. The distillation dehydration apparatus according to claim 1, wherein said combined column apparatus further comprises a first reboiler (E406A) and a second reboiler (E406B) in circulation communication with the bottoms of the combined column (C401), respectively;

the first reboiler (E406A) further communicating the molecular sieve unit and the rectification column pre-heating unit, the first reboiler (E406A) for heating molecular sieve gas from the molecular sieve unit to the bottom liquid phase of the combined column (C401);

the second reboiler (E406B) further communicating the rectifying column preheating means and the rectifying column means, the second reboiler (E406B) for heating the overhead gas phase feed from the rectifying column means to the bottom liquid phase of the combining column (C401);

the bottom of the combined tower (C401) is also communicated with a waste mash treatment device and is used for discharging waste mash at the bottom of the tower.

4. The distillation dehydration device according to claim 1, wherein said rectifying tower feed preheating device comprises a rectifying tower first preheater (E409) and a rectifying tower second preheater (E410), a rectifying tower third preheater (E407) and a second cooler (E414) which are communicated in sequence;

the rectifying tower first preheater (E409) is also communicated with a combined tower (C401), a mash three-stage preheater (E403) and the rectifying tower device, and is used for heating the waste liquid from the rectifying tower device to the liquid-phase feed of the rectifying tower device;

said rectifier second preheater (E410) further communicating said rectifier means and a mash secondary preheater (E402) for heating the vapor from said rectifier means to the liquid phase feed to said rectifier means;

the rectifying tower third preheater (E407) is also communicated with the combined tower (C401), the rectifying tower device, the first reboiler (E406A) and the finished product ethanol receiving device, and is used for heating the material from the first reboiler (E406A) to produce a gas phase from a top measuring line of the combined tower (C401);

the second cooler (E414) is communicated with the rectifying tower third preheater (E407) and the finished product ethanol receiving device and is used for cooling the circulating water to the molecular sieve gas from the molecular sieve device which passes through the first reboiler (E406) and the rectifying tower third preheater (E407);

wherein the liquid phase feed to the rectification column unit comprises inline produced liquid from a combi-column (C401), molecular sieve weak liquor from the molecular sieve unit and fusel oil weak liquor from the rectification column unit.

5. The distillation dehydration unit of claim 1, wherein said rectification column means comprises a third reboiler (E411) in circulation communication with the bottom of rectification column (C402) and fusel oil extraction tank (V409) in sequential communication;

the third reboiler (E411) is also communicated with the second preheater (E410) of the rectifying tower and a steam heat source and is used for heating the steam heat source to the bottom liquid phase of the rectifying tower (C402);

the fusel oil extraction tank (V409) is used for separating a liquid phase extracted from a measuring line of the rectifying tower (C402), fusel oil extracted from the top of the fusel oil extraction tank (V409) is sent to a fusel oil receiving tank, and fusel oil light wine extracted from the bottom of the fusel oil extraction tank (V409) is sent to a first preheater (E409) of the rectifying tower for heating.

6. The distillation dehydration apparatus according to claim 1, wherein said molecular sieve apparatus comprises a plurality of molecular sieve adsorption beds connected in parallel, a first steam superheater (E412) and a second steam superheater (E413).

7. The distillation dehydration apparatus of claim 6, wherein said molecular sieve adsorbent bed has two operating states: an adsorption state and a regeneration state; wherein when a portion of the plurality of molecular sieve adsorbent beds are set to an adsorption state, another portion of the plurality of molecular sieve adsorbent beds are set to a regeneration state;

preferably, in the adsorption state, the top of the molecular sieve adsorption bed is communicated with the first reboiler (E406A), and the bottom of the molecular sieve adsorption bed is communicated with the top of the rectifying tower (C402) through the first steam superheater (E412), and the molecular sieve adsorption bed is used for adsorbing water in the gas-phase material which comes from the rectifying tower (C402) and is heated by the first steam superheater (E412);

in the regeneration state, the top of the molecular sieve adsorption bed is communicated with a second steam superheater (E413), and the bottom of the molecular sieve adsorption bed is communicated with a first preheater (E409) of the rectifying tower; the second steam heater (E413) heats the molecular sieve gas generated in an adsorption state from the molecular sieve adsorbent bed using a steam heat source; the heated molecular sieve gas is used for regenerating a molecular sieve adsorption bed, and the generated molecular sieve weak liquor is subjected to heat exchange through a first preheater (E409) of the rectifying tower so as to be fed to the rectifying tower (C402).

8. A preparation method of a distiller's dried grain protein feed comprises the following steps: passing the matured mash to an ethanol distillation dehydration unit of any one of claims 1-7 and treating the spent mash withdrawn from the bottom of the combined column (C401) in said unit to obtain a distiller's dried grain protein feed.

9. The process according to claim 8, wherein the bottom temperature of the combined column (C401) is 80-90 ℃, preferably 80-85 ℃.

10. The process according to claim 8 or 9, wherein the treatment comprises subjecting the waste mash to solid-liquid separation, evaporation and drying in sequence.

Technical Field

The invention relates to a distillation dehydration device, in particular to a fuel ethanol distillation dehydration device and a preparation method of a distiller's dried grain protein feed.

Background

In China, the popularization and use of the ethanol gasoline for vehicles is an important measure for implementing the national energy strategy. As the key point of renewable fuels, developing fuel ethanol has great significance for adjusting the energy structure of China, developing petroleum substitute resources, improving the specific gravity of clean fuel, improving the emission of automobile exhaust and the quality of atmospheric environment, developing low-carbon economy, promoting the virtuous cycle and sustainable development of agricultural production and consumption, realizing agricultural efficiency improvement and increasing the income of farmers.

The process for producing fuel ethanol by using corn starch as a raw material generally comprises a starch raw material liquefaction working section, a fermentation working section, a distillation dehydration working section and a waste mash treatment working section.

However, in the distillation section of the conventional fuel ethanol project, a three-tower differential pressure distillation process is adopted. The distillation main device comprises a negative pressure tower, a medium pressure tower and a high pressure tower, and the process has high requirements on the quality of steam and causes high steam energy consumption. And the temperature at the bottom of the negative pressure tower is higher, when the corn fermentation mash is used as a raw material, amino acid and saccharide in the waste mash are easy to generate Maillard reaction at high temperature, so that the dried vinasse protein feed obtained by subsequent treatment is deepened, the quality is reduced, and the price is lower.

CN108103112A discloses that in the waste mash treatment section, the waste hot gas generated in the evaporation concentration process is treated and used as the heat source of the distillation apparatus, because the end-effect juice gas in the evaporation concentration process is about 50 ℃, the quality is low, and the juice gas can be sent to the distillation system as the heat source after additional heating treatment. However, this would additionally increase the power consumption of the device. Also, the temperature of the produced mash can reach 90 ℃ at the maximum, which is still too high, resulting in failure to obtain high quality distiller's dried grain protein feed.

Disclosure of Invention

The invention aims to solve the problems of high energy consumption of devices and low quality of distiller's dried grain protein feed caused by high temperature of waste mash in the prior art, and provides a fuel ethanol distillation dehydration device and a preparation method of the distiller's dried grain protein feed.

In order to achieve the above object, in a first aspect, the present invention provides a fuel ethanol distillation dehydration device, which comprises a mash preheating device, a combined tower device, a rectifying tower feeding preheating device, a rectifying tower device and a molecular sieve device which are sequentially communicated; the combined tower device comprises a combined tower C401, wherein a gas phase inlet communicated with a heat source is arranged at the bottom of the combined tower C401 and is used for providing heat for the combined tower C401.

In a second aspect, the present invention provides a process for the preparation of a distiller's dried grain protein feed, comprising passing a mature mash to the above-mentioned ethanol distillation dehydration unit and treating a spent mash withdrawn from the bottom of a combined column C401 in said unit.

Through the technical scheme, waste gas in an evaporation working section can be directly introduced into the bottom of the combined tower as a heat source without additional heating treatment, so that waste heat resources are fully utilized, the using amount of fresh steam is reduced, the energy consumption of the device is effectively reduced, and waste mash can be controlled at a lower temperature, so that the probability of Maillard reaction in the mash at the bottom of the negative pressure tower is greatly reduced, the color and quality of the distiller's dried grain protein feed obtained through subsequent treatment are remarkably improved, and the content of amino acid is increased. In the embodiment of the invention, compared with the traditional fuel ethanol three-tower differential pressure distillation device, the consumption of fresh steam is reduced by 30%, the power consumption is reduced by 22%, the number of equipment of a pump, a heat exchanger and a tank is obviously reduced, the temperature of waste mash does not exceed 85 ℃, the investment is reduced, and the energy consumption of the device is obviously reduced.

Drawings

FIG. 1 is a flow chart of a distillation dehydration device and a process for fuel ethanol provided by the invention;

FIG. 2 is a process flow diagram of a conventional three-column differential pressure ethanol distillation dehydration plant in a comparative example.

Description of the reference numerals

E401: mash primary preheater E402: mash secondary preheater E403: three-stage mash preheater

E404: first cooler E406A: first reboiler E406B: second reboiler

E407: second cooler E409: the rectifying tower first preheater E411: third reboiler

E412: first steam superheater E410: second preheater E413 of rectifying column: second steam superheater

E414: second cooler V409: fusel oil extraction tank T401A: molecular sieve adsorption bed A

C401: combination column C402: rectifying column T401B: molecular sieve adsorption bed B

C301: second crude distillation column C302: the second rectifying column C303: third rectifying tower

Detailed Description

The endpoints of the ranges and any values disclosed herein are not limited to the precise range or value, and such ranges or values should be understood to encompass values close to those ranges or values. For ranges of values, between the endpoints of each of the ranges and the individual points, and between the individual points may be combined with each other to give one or more new ranges of values, and these ranges of values should be considered as specifically disclosed herein.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used herein in the description is for the purpose of describing particular embodiments and is not intended to be limiting of the invention.

In a first aspect, the present invention provides a fuel ethanol distillation dehydration device, as shown in fig. 1, wherein the device comprises a mash preheating device, a combined tower device, a rectifying tower feeding preheating device, a rectifying tower device and a molecular sieve device which are sequentially communicated; the combined tower device comprises a combined tower C401, wherein a gas phase inlet communicated with a heat source is arranged at the bottom of the combined tower C401 and is used for providing heat for the combined tower C401.

In the above apparatus provided by the present invention, the combined column C401 is provided with a gas phase inlet at the bottom thereof, through which a heat medium can be introduced into the combined column C401, and the gas phase inlet is provided to communicate with a heat source. The gas phase heat source for providing heat in the present invention is not particularly limited, and may be steam with a temperature above 85 ℃, preferably evaporation waste gas delivered from the waste mash treatment section, the evaporation waste gas is steam after the drying stage, and the drying stage belongs to the steps of the waste mash treatment section and the conventional operation steps in the field. The inventor utilizes the waste gas in the waste mash treatment section of fuel ethanol to recycle the waste heat, thereby reducing the energy consumption of the device, reducing the using amount of fresh steam, simultaneously well controlling the temperature of the waste mash, greatly reducing the probability of Maillard reaction, and improving the color and quality of the dried distillers' grain protein feed obtained by subsequent treatment.

According to a preferred embodiment of the present invention, as shown in FIG. 1, the mash preheating device comprises a first cooler E404 and a first mash preheater E401, a second mash preheater E402 and a third mash preheater E403, which are connected in series. The type of mash preheater is not particularly limited in the present invention and may be a conventional choice in the art, and preferably the heat exchanger is a shell and tube heat exchanger. The cooler is not particularly limited in the present invention, and may be a conventional one in the art, and is preferably cooled by using circulating water as a cooling medium.

Preferably, the mash primary preheater E401 is also in communication with the mature mash feed tank and the combining column C401.

Preferably, the first cooler E404 is in communication with the mash primary preheater E401, the combining column C401 and the vacuum system for cooling at least a portion of the reflux steam from the top of the mash primary preheater E401 using recycled water, the resulting non-condensable gas being sent to the vacuum system and the resulting condensed liquid being sent to the combining column C401. That is, the cooled condensate is refluxed to the combining column C401, and the non-condensable gas therein is sent to the vacuum system. The non-condensable gases are known in the art and include, but are not limited to, hydrogen, carbon monoxide, carbon dioxide or methane.

Preferably, the mash secondary preheater E402 is also in communication with the rectification column feed preheater unit and the steam condensate receiving unit for heating the mature mash with steam from the rectification column feed preheater unit.

Preferably, the mash tertiary preheater E403 is also in communication with the combining column C401, the rectification column feed preheater and the wastewater receiving means for heating the spent liquor from the rectification column feed preheater to mature mash.

According to a preferred embodiment of the present invention, as shown in fig. 1, the combined column apparatus further comprises a first reboiler E406A and a second reboiler E406B in circulation communication with the bottoms of the combined column C401, respectively. The reboiler is not particularly limited in the present invention and may be selected conventionally in the art, and preferably, the two streams in the reboiler are countercurrent isolated heat exchange.

Preferably, the first reboiler E406A is further in communication with the molecular sieve device and the rectification column preheating device, and the first reboiler E406A is used for heating the molecular sieve gas from the molecular sieve device to the liquid bottom phase of the combined column C401.

According to the invention, the second reboiler E406B is also in communication with the rectifying column preheating means and the rectifying column means, and the second reboiler E406B is used for heating the overhead gas phase feed from the rectifying column means to the bottom liquid phase of the combined column C401.

Preferably, the bottom of the combined tower C401 is also communicated with a waste mash treatment device, and is used for discharging waste mash at the bottom of the tower and sending the waste mash to a waste mash treatment section. The waste mash treatment section is a conventional treatment section in the art, and the waste mash treatment section is not particularly limited in the present invention. By adopting the device provided by the invention, after the waste mash is obtained, the dried vinasse protein feed obtained by subsequent treatment is obviously improved in color and luster and obviously improved in quality.

According to a preferred embodiment of the present invention, as shown in fig. 1, the rectifying tower feed preheating device comprises a rectifying tower first preheater E409, a rectifying tower second preheater E410, a rectifying tower third preheater E407 and a second cooler E414 which are communicated in sequence.

The first rectifying tower preheater E409 is also communicated with a combined tower C401, a mash three-stage preheater E403 and the rectifying tower device, and is used for heating the waste liquid from the rectifying tower device to the liquid-phase feed of the rectifying tower device;

the rectification column second preheater E410 is also in communication with the rectification column apparatus and the mash second stage preheater E402 for heating the steam from the rectification column apparatus to the liquid phase feed to the rectification column apparatus.

Preferably, the rectifying tower third preheater E407 is further communicated with the combined tower C401, the rectifying tower device, the first reboiler E406A and the finished product ethanol receiving device, and is used for heating the material from the first reboiler E406A to the top side line extracted gas phase from the combined tower C401. The finished product ethanol receiving device is used for storing liquid phase ethanol obtained after ethanol steam is cooled, and the volume content of the ethanol is more than 99.5%.

Preferably, the rectifying tower first preheater E409 and the rectifying tower second preheater E410 are respectively used for heating the waste liquid from the rectifying tower device and the steam from the rectifying tower device to the liquid phase feed of the rectifying tower device, and the liquid phase feed of the rectifying tower device comprises the inline produced liquid from the combined tower C401, the molecular sieve light wine from the molecular sieve device and the fusel oil light wine from the rectifying tower device. The rectification column third preheater E407 is used to heat the feed from the first reboiler E406A to the top inline withdrawn gas phase from the combined column C401.

Preferably, the second cooler E414 is in communication with the rectifying column third preheater E407 and the finished ethanol receiving device for cooling the circulating water with the molecular sieve gas from the molecular sieve device that has passed through the first reboiler E406 and the rectifying column third preheater E407.

Wherein the liquid phase feed to the rectification column unit comprises a inline produced stream from a combiner column C401, a molecular sieve weak liquor from the molecular sieve unit, and a fusel oil weak liquor from the rectification column unit.

According to a preferred embodiment of the present invention, the rectification column apparatus comprises a third reboiler E411 in circulating communication with the bottom of the rectification column C402, and the rectification column C402 and the fusel oil extraction tank V409 in sequential communication.

The third reboiler E411 is also communicated with the second preheater E410 of the rectifying tower and a steam heat source, and the third reboiler E411 is used for heating the steam heat source to the bottom liquid phase of the rectifying tower C402. After the fuel ethanol dehydration device provided by the invention is adopted, the consumption of fresh steam is obviously reduced, and the steam consumption is saved by about 20-30% compared with the traditional three-tower differential pressure ethanol distillation dehydration process, so that the energy consumption of the whole plant is reduced.

In the present invention, the fusel oil extraction tank V409 is used to separate the liquid phase taken from the measurement line of the rectification column C402. The arrangement mode of the line sampling port is not particularly limited, and can be selected conventionally in the field. The produced liquid of the C402 measuring line of the rectifying tower is separated in a fusel oil extraction tank V409, the separation is not particularly limited, the conventional operation in the field can be realized, specifically, water can be used as an extracting agent to extract the produced liquid, the main component of the produced liquid is fusel oil serving as a product, the main component of the produced liquid is water serving as a fusel oil weak liquor, the fusel oil weak liquor returns to a first preheater of the rectifying tower, and the heated fusel oil weak liquor is sent to the rectifying tower for distillation and purification.

According to a preferred embodiment of the present invention, the molecular sieve device comprises a plurality of molecular sieve adsorbent beds connected in parallel, a first steam superheater E412 and a second steam superheater E413. The number of the molecular sieve adsorbent beds is not particularly limited in the present invention, and at least 2, for example, 2, 3 or more, and as shown in fig. 1, there are provided a molecular sieve adsorbent bed A T401A and a molecular sieve adsorbent bed B T401B.

According to a preferred embodiment of the present invention, the molecular sieve device comprises an adsorption state and a regeneration state which are continuously alternated.

Preferably, in the adsorption state, the top of the molecular sieve adsorption bed is communicated with the first reboiler E406A, and the bottom of the molecular sieve adsorption bed is communicated with the top of the rectification column C402 through the first steam superheater E412, and the molecular sieve adsorption bed is used for adsorbing water in the gas-phase material which comes from the rectification column C402 and is heated by the first steam superheater E412.

Preferably, in the regeneration state, the top of the molecular sieve adsorption bed is communicated with a second steam superheater E413, and the bottom of the molecular sieve adsorption bed is communicated with a rectifying tower first preheater E409; the second steam heater E413 uses a steam heat source to heat the molecular sieve gas from the molecular sieve adsorption bed in the adsorption state, the heated molecular sieve gas returns to the molecular sieve adsorption bed in the regeneration state to regenerate the molecular sieve adsorption bed in the regeneration state, and the generated molecular sieve weak liquor is subjected to heat exchange by the first preheater E409 of the rectifying tower to be fed to the rectifying tower C402.

In a second aspect, the invention provides a preparation method of distiller's dried grain protein feed, which comprises the steps of introducing mature mash into the ethanol distillation dehydration device, and treating waste mash extracted from the bottom of a combined tower C401 in the device to obtain the distiller's dried grain protein feed.

Preferably, the bottom temperature of the combined column C401 is between 80 and 90 ℃, preferably between 80 and 85 ℃. The inventor of the invention finds that the evaporation waste gas in the waste mash treatment section of the fuel ethanol production process is used as a gas phase heat source of the combination tower C401, the temperature of the waste mash at the bottom of the combination tower can be controlled at a lower temperature, the probability of Maillard reaction in the waste mash at the temperature is greatly reduced, and the color and the quality of a dried distillers' grain protein feed product obtained by subsequent treatment are obviously improved.

Preferably, the treatment of the waste mash in the present invention comprises subjecting the waste mash to solid-liquid separation, evaporation and drying in sequence. The operation of the solid-liquid separation in the present invention is not particularly limited, and may be a routine choice in the art, for example, a centrifuge is used to perform solid-liquid separation to obtain wet grains and clear liquid. The evaporation operation is not particularly limited in the invention, and can be selected conventionally in the field, and thick slurry can be obtained after evaporation is carried out on part of clear liquid. The drying operation is not particularly limited in the present invention, and may be a routine choice in the art, such as drying the resulting thick slurry and wet grains using a dryer. And cooling to obtain the distiller's dried grain protein feed.

The invention improves and optimizes the traditional fuel ethanol device, improves the traditional three-tower differential pressure distillation device into a two-tower differential pressure distillation device, effectively reduces the number of heat exchangers and pumps in the device, and reduces the equipment investment. Moreover, the inventor of the invention finds that the waste heat resource is reasonably utilized, namely the evaporation waste gas in the waste mash treatment section is directly introduced into the tower bottom of the combined tower, so that the purposes of energy conservation and emission reduction can be achieved, an unexpected effect is achieved on the temperature control of the waste mash, the temperature of the mash at the tower bottom of the combined tower is controlled to be 80-85 ℃, and the probability of Maillard reaction in the mash at the tower bottom of the negative pressure tower is greatly reduced. Not only obviously reduces the energy consumption of the whole process, but also obviously improves the color of the dried distillers' grain protein feed obtained by subsequent treatment.

The present invention will be described in detail below by way of examples.

Example 1

As shown in FIG. 1, the process for producing anhydrous fuel ethanol from mature mash feedstock according to the two-column differential pressure process provided by the present invention is as follows:

the flow rate of mature mash from upstream is 320t/h, and the mature mash enters from the middle upper part of the combined tower C401 after being heated to about 65 ℃ step by a first-stage mash heat exchanger E401, a second-stage mash heat exchanger E402 and a third-stage mash heat exchanger E403. The combined column C401 was operated at subatmospheric pressure, a column head pressure of-0.05 MPaG, a column bottom pressure of-0.06 MPaG, a column bottom temperature of about 83 ℃ and a column top temperature of about 55 ℃. And discharging the bottom mash from the bottom of the combination tower, wherein the ethanol content in the waste mash is less than 0.04 mass%. And conveying the waste mash to a waste mash treatment working section, sequentially carrying out solid-liquid separation, evaporation and drying, and cooling to obtain the distiller's dried grain protein feed with the mass flow of about 33.75 t/h. The bottom of the combined column C401 is directly fed with evaporation waste gas from a waste mash treatment section as a heat source except for heat supply of a first reboiler E406A and a second reboiler E406B, wherein the evaporation waste gas comprises water vapor, the pressure is-0.06 MPaG, the temperature is about 85 ℃, and the flow rate is 15 t/h.

Mature mash enters a combined tower C401, ethanol steam at the tower top is cooled into condensate through a first cooler E404 and a mash primary preheater E401, the condensate flows back to the upper part of the combined tower C401, and non-condensable gas in the condensate is pumped out of the system through a vacuum pump. The produced liquid on the measuring line of the combined tower C401, the dealcoholized liquid and the molecular sieve light wine from the molecular sieve device enter a first preheater E409 of the rectifying tower together, pass through a second preheater E410 of the rectifying tower, are heated to about 135 ℃ and then are used as feed materials and are sent to the middle part of the rectifying tower C402. The top side line produced liquid of the combined column C401 enters the top of the rectifying column C402 after being heated to about 78 ℃ by a third preheater E407 of the rectifying column.

The temperature of the bottom of the rectifying tower C402 is about 130 ℃, the pressure of the bottom of the rectifying tower C402 is 0.13MPaG, the temperature of the steam is 170 ℃, the pressure of the steam is 0.7MPaG, and the flow rate of the steam is 35 t/h. The steam is passed through a third reboiler E411 and continues to heat the rectification column second preheater E410 and the mash second stage preheater E402 in that order. After being discharged, part of the tower bottom wastewater of the rectifying tower C402 is sequentially heated by a first preheater E409 and a mash tertiary preheater E403 of the rectifying tower, and finally enters a size mixing section to be reused as size mixing water. In the rectifying tower C402, a gas phase is extracted from the top of the tower, one part of the gas phase is sent to the rectifying tower C402 as reflux after heat exchange by a second reboiler E406B at the bottom of the combined tower C401, and the other part of the gas phase is sent to a molecular sieve device after being heated to about 125 ℃ by a first steam superheater E412. And (3) extracting fusel mixed oil from a middle measuring line of the rectifying tower C402 at the temperature of about 110 ℃, sending the fusel mixed oil to a fusel oil extraction tank V409, taking the main component of the fusel oil as a product, taking the main component of the fusel oil as water, and sending the fusel oil light wine back to a first preheater E409 of the rectifying tower, heating the fusel oil light wine, and then sending the fusel oil light wine to the rectifying tower C402 for distillation and purification.

Molecular sieve adsorbent bed A T401A and molecular sieve adsorbent bed B T401B were operated in a continuous cycle wherein T401B was regenerated as T401A was adsorbed. In the adsorption state, the temperature of molecular sieve adsorbent bed A T401A was about 125 ℃ and the adsorption pressure was 0.1 MPaG. The ethanol steam exchanges heat from the upper part of a molecular sieve adsorption bed A T401A through a first reboiler E406A and a third preheater E407 of a rectifying tower, and is condensed through a second cooler E414 to obtain an anhydrous ethanol product, and the anhydrous ethanol product is sent to a finished product tank, wherein the flow rate of the finished ethanol product is 37.5 t/h.

In a regeneration state, ethanol steam flows out of the top of the molecular sieve adsorption bed B T401B, enters the second steam superheater E413 through a butterfly valve, is heated, enters the molecular sieve adsorption bed A T401A from the top, and regenerates the molecular sieve adsorption bed A T401A.

By checking, the consumption of fresh steam in the distillation dehydration section is 36t/h, the power consumption is 22.53KWh/t ethanol product, and the number of tanks, heat exchangers and pumps in the distillation dehydration section is 67. The results are shown in Table 1.

Comparative example 1

As shown in FIG. 2, the conventional three-tower differential pressure process for producing anhydrous fuel ethanol from mature mash feedstock is as follows:

the second coarse distillation tower C301 is operated under negative pressure, the pressure at the top of the tower is-0.05 MPaG, the pressure at the bottom of the tower is-0.06 MPaG, the temperature at the bottom of the tower is about 85 ℃, the temperature at the top of the tower is about 55 ℃, and mature mash with the flow rate of 320t/h enters from the middle upper part of the second coarse distillation tower C301 after being preheated by two stages of heat exchangers respectively. The bottom mash is discharged from the bottom of the second coarse distillation tower C301, one part of the bottom mash exchanges heat with a reboiler at the bottom of the second coarse distillation tower C301 for reflux, and the other part of the bottom mash is sent to a waste mash treatment section. And conveying the waste mash to a waste mash treatment working section, sequentially carrying out solid-liquid separation, evaporation and drying, and cooling to obtain the distiller's dried grain protein feed with the mass flow of about 240 t/h.

After the materials enter the second coarse distillation tower C301, alcohol in mash is heated and evaporated by steam at the bottom of the coarse distillation tower and moves to the top of the tower, and the alcohol overflows from the top of the second coarse distillation tower C301. After the overflowed alcohol vapor is cooled by a cooler at the top of the tower, condensate in the alcohol vapor reflows to the upper part of the tower, and the non-condensable gas is sent to a vacuum system after secondary cooling. The second crude distillation column C301 side draw is sent to the middle part of a third rectifying column C303 to be used as the feed of the third rectifying column C303.

The second rectification column C302 is pressurized, the bottom pressure is 0.5MPaG, the top pressure is 0.4MPaG, the top temperature is 128 ℃ and the bottom temperature is 155 ℃. The crude wine enters the second rectifying tower C302, the alcohol steam overflows from the top of the tower and enters the third rectifying tower C303 through a reboiler at the bottom of the third rectifying tower C303. The reboiler at the bottom of the second rectifying tower C302 takes fresh steam as a heat source, the temperature of the steam is 170 ℃, the pressure is 0.7MPaG, and the flow is 50 t/h. And (4) sending the waste liquid extracted from the bottom of the second rectifying tower C302 to a powder slurry working section for stirring.

The third rectification column C303 was operated at atmospheric pressure, with a top pressure of 0.1MPaG, a top pressure of 0.07MPaG, a top temperature of 95 ℃ and a bottom temperature of 120 ℃. Alcohol enters the third rectifying tower C303 and continuously overflows from the top of the third rectifying tower C303 under the action of steam, one part of alcohol enters the second rectifying tower C302 through a reboiler at the bottom of the second coarse distillation tower C301, and the other part of alcohol enters an adsorption bed from the bottom after being heated to about 125 ℃ through a steam superheater for dehydration. The finished product alcohol vapor overflows from the upper part of the adsorption bed, is sent to a finished product storage tank after being subjected to heat exchange by a mash preheater, and the flow rate of the finished product ethanol is 37.5 t/h.

Part of the finished product wine gas from the top of the adsorption bed enters a secondary steam superheater through a butterfly valve to be heated to about 125 ℃, and the finished product wine gas is used as a heat source and enters another adsorption bed through the butterfly valve from the upper part of the adsorption bed to regenerate the molecular sieve, and the formed molecular sieve light wine enters a light wine tank.

The fusel oil and alcohol/water mixture is extracted from the middle upper part of the second rectifying tower C302, enters a fusel oil collecting tank, and is fully mixed and extracted with deionized water entering the collecting tank from the upper part through a control valve. The fusel oil separated by extraction is extracted from the upper part of the fusel oil collecting tank, and the fusel oil light wine is extracted from the bottom.

By checking, the consumption of fresh steam in the distillation dehydration section is 51t/h, the power consumption is 33.65KWh/t ethanol product, and the number of tanks, heat exchangers and pumps in the distillation dehydration section is 86. The results are shown in Table 1.

TABLE 1

As can be seen from the results in Table 1, by adopting the fuel ethanol distillation dehydration device provided by the invention, the fresh steam consumption of the distillation section in the embodiment 1 is reduced by 30%, the power consumption is reduced by 22%, the equipment quantity of a pump, a heat exchanger and a tank is obviously reduced, the temperature of waste mash does not exceed 85 ℃, and the color of the distiller's dried grain protein feed is obviously improved.

The invention obviously reduces the energy consumption of the whole process by improving and optimizing the traditional fuel ethanol device. The inventor of the invention surprisingly discovers that the waste heat resource is reasonably utilized, namely the waste gas in the waste mash treatment working section of the invention is directly introduced into the bottom of the combined tower, so that the purposes of energy conservation and emission reduction can be achieved, the waste mash can be controlled at a lower temperature, the probability of Maillard reaction in the mash at the bottom of the negative pressure tower is greatly reduced, the color of the dried distillers' grain protein feed obtained by subsequent treatment is obviously improved, the amino acid content is increased, and the nutritional value of the product is improved.

The preferred embodiments of the present invention have been described above in detail, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, many simple modifications can be made to the technical solution of the invention, including combinations of various technical features in any other suitable way, and these simple modifications and combinations should also be regarded as the disclosure of the invention, and all fall within the scope of the invention.