Dehydrating and drying method of white spirit vinasse

Abstract

The invention provides a dewatering and drying method of white spirit vinasse, which comprises the following steps: S1, extruding and dewatering white spirit vinasse under the extrusion force of not more than 0.8 MPa to obtain vinasse residue with the water content of 55-60%; s2, dehumidifying and drying the dregs at the temperature of 52-55 DEG C to obtain primarily dried dregs with the water content of 38-42%; and S3, dehumidifying and drying the primarily-dried dregs at the temperature of 72-78 DEG C to obtain available dregs with the water content of 12%. According to the method, the used extrusion force is low, caking of the distiller's grains is avoided, meanwhile, low-temperature hot air drying is adopted, the energy consumption is low, and the obtained distiller's grains are high in nutritional value and more thorough in moisture removal.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of distiller's grains processing, and particularly relates to a dehydration drying method and device for distiller's grains. BACKGROUND

[0002] Distiller's grains is a by-product after brewing, and the initial water content of the distiller's grains is 65-70%, which contains a high amount of water. Before the recycling of the distiller's grains, the distiller's grains needs to be dehydrated. The current dehydration methods for the distiller's grains include airing, hot air drying and pressing. Among them, the commonly used methods in industry are hot air drying and pressing. The hot air drying method needs to be dried at a high temperature of 800-1000 DEG C for 8-12 hours, which has high energy consumption. The pressing method needs to be dehydrated under a pressure of 1.5-2.0 MPa. In the process of pressing, the fiber structure of the distiller's grains is damaged due to the excessive pressure, which is easy to form clumps and is difficult to remove the combined water. SUMMARY

[0003] Therefore, the application provides a dehydration drying method for distiller's grains, which has low energy consumption and prevents clumping of the distiller's grains, and is convenient for recycling.

[0004] To achieve the above-mentioned purpose, the application adopts the following technical scheme: The application provides a dehydration drying method for distiller's grains, which comprises the following steps: S1, extruding and dehydrating the distiller's grains, the extrusion degree is not greater than 0.8 MPa, and the obtained distiller's residue has a water content of 55-60%; S2, dehumidifying and drying the distiller's residue at a temperature of 52-55 DEG C, and obtaining preliminary dried distiller's residue with a water content of 38-42%; S3, dehumidifying and drying the preliminary dried distiller's residue at a temperature of 72-78 DEG C, and obtaining available distiller's residue with a water content of 12%.

[0005] Preferably, before the step S1, the distiller's grains needs to be screened to remove impurities in the distiller's grains.

[0006] Preferably, before the step S1, citric acid is added to the distiller's grains to maintain the pH of the distiller's grains at 4.5-5.

[0007] Preferably, the mass fraction of the added citric acid is 0.1-0.15%.

[0008] Preferably, after the step S1, not only the distiller's residue with a water content of 55-60% is obtained, but also liquid distiller's liquid with a water content of 85-95% is obtained, and the liquid distiller's liquid is subjected to membrane treatment and separation to obtain concentrated phase retentate and dilute phase permeate, which are recycled.

[0009] Preferably, the device used for dehumidifying drying in steps S2 and S3 comprises: a drying channel, sequentially comprising a first channel, a second channel and a third channel, which are in communication with each other and can be adjusted in temperature by a temperature regulator; a conveying belt arranged in the drying channel and conveying the distiller's grains with a water content of 55-60% along the length direction of the drying channel, and the distiller's grains with a water content of 55-60% sequentially pass through the first channel, the second channel and the third channel, wherein, in step S2, the distiller's grains are dehumidified and dried at a temperature of 52-55℃ to obtain preliminary dried distiller's grains with a water content of 38-42%, which is completed in the first channel; in step S3, the preliminary dried distiller's grains are dehumidified and dried at a temperature of 72-78℃ to obtain usable distiller's grains with a water content of 12%, which is completed in the third channel.

[0010] Preferably, the length of the first channel is not more than 7.5 m; and / or, the length of the second channel is 2-2.5 m; and / or, the length of the third channel is 7.5-15 m.

[0011] Preferably, the conveying belt is a mesh belt, the mesh diameter of the mesh belt is 2 mm, and the air permeability is not less than 90%.

[0012] Preferably, temperature sensors and humidity sensors are arranged in the first channel and the third channel.

[0013] Compared with the prior art, the present application has the following beneficial effects: (1) The present application combines hot air drying with extrusion method, first removes the water in the distiller's grains by a small extrusion force, then removes the water by segmented hot air drying, first removes the water on the surface of the distiller's grains and the free water in the capillary by dehumidifying and drying at a temperature of 52-55℃, and then removes the adsorbed water and part of the micropore combined water combined with the fiber and protein in the distiller's grains by dehumidifying and drying at a temperature of 72-78℃. The present application uses low extrusion force to avoid the caking of the distiller's grains, and uses low-temperature hot air drying to reduce energy consumption and obtain distiller's grains with high nutritional value and more complete water removal.

[0014] (2) The present application adds citric acid to the distiller's grains before dehydrating and drying, maintains the activity of flavor substances in the distiller's grains, and ensures the recovery of subsequent flavor substances. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1A flow chart of the white spirit lees dehydration drying method provided by the present application. DETAILED DESCRIPTION

[0016] The present application will be further described in detail below with specific examples, so that those skilled in the art can more clearly understand the present application.

[0017] White spirit lees is a by-product after brewing, and the initial moisture content of the lees is 65-70%, containing a high amount of water. Before recycling the white spirit lees, it needs to be dehydrated. The current dehydration methods for white spirit lees include airing, hot air drying and pressing. Among them, the commonly used methods in industry are hot air drying and pressing. Hot air drying requires drying at a high temperature of 800-1000℃ for 8-12h, which is high in energy consumption. Pressing requires extrusion dehydration under a pressure of 1.5-2.0MPa. In the extrusion process, the fiber structure of the white spirit lees is damaged due to the excessive pressure, which is easy to form clumps and is difficult to remove combined water.

[0018] To solve the above technical problems, in combination with the fact that Figure 1 The present application provides a white spirit lees dehydration drying method, which comprises the following steps: S1, extruding and dehydrating the white spirit lees, the extrusion intensity being not greater than 0.8MPa, to obtain lees residue with a water content of 55-60%; Specifically, in some embodiments, the extrusion equipment used is a screw filter press. The extrusion intensity is not specifically limited, and it can be 0.8MPa, 0.7MPa, etc. The extrusion intensity used in the present application is relatively low, which can avoid the damage of fibers and proteins in the lees.

[0019] S2, dehumidifying and drying the lees residue at a temperature of 52-55℃ to obtain preliminary dried lees residue with a water content of 38-42%; Specifically, the temperature is not specifically limited, for example, it can be 52℃, 53℃ or 55℃, and the specific temperature is determined according to the actual situation. In some embodiments, in order to achieve better dehumidification effect, the thickness of the dehumidified material is about 5cm, and too thick will affect the drying effect.

[0020] S3, dehumidifying and drying the preliminary dried lees residue at a temperature of 72-78℃ to obtain usable lees residue with a water content of 12%.

[0021] Specifically, the temperature is not specifically limited, for example, it can be 72℃, 75℃ or 78℃, and the specific temperature is determined according to the actual situation.

[0022] In the technical scheme, the hot air drying and the extrusion are combined, the moisture in the distiller's grains is preliminarily removed through a small extrusion force, and then the moisture is removed and dehydrated through the segmented hot air drying, the moisture is removed and dehydrated through the temperature of 52-55 DEG C first, the attached water on the surface of the distiller's grains and the free water in the capillary are removed, and then the moisture is removed and dehydrated through the temperature of 72-78 DEG C, the adsorbed water and part of the micropore combined water combined with the fiber and the protein in the distiller's grains are removed. The extrusion force used in the application is low, the distiller's grains are prevented from caking, the low-temperature hot air drying is used, the energy consumption is low, the obtained distiller's grains have high nutritional value, and the moisture removal is more thorough.

[0023] Further, before the extrusion dehydration of the distiller's grains in step S1, the distiller's grains need to be screened to remove impurities. In some embodiments, the specific operation is that the original distiller's grains are sent to a double-layer vibrating screen (pore size 5mm, material 316L stainless steel, corrosion prevention) by a screw conveyor to remove part of the rice hull, gravel, glass and other impurities.

[0024] Further, before the extrusion dehydration of the distiller's grains in step S1, citric acid is added to the distiller's grains to maintain the pH of the distiller's grains at 4.5-5. In some embodiments, the mass fraction of the added citric acid is 0.1-0.15%, and preferably the mass fraction of the citric acid is 0.1%.

[0025] In some embodiments, after the extrusion of the distiller's grains in step S1, not only the distiller's grains with a water content of 55-60% are obtained, but also the liquid distiller's grains liquid with a water content of 85-95% is obtained. The liquid distiller's grains liquid is subjected to membrane treatment and separation to obtain concentrated phase retentate and dilute phase permeate for recycling. In some embodiments, the specific membrane separation operation is as follows: After the liquid distiller's grains liquid is subjected to bag filter to remove suspended solids, it is sent to a liquid distiller's grains liquid storage tank, and then is sent into a ceramic membrane assembly by a screw pump. The ceramic membrane is made of alpha-aluminum oxide and has a pore size of 50kDa. The operating pressure is 0.3-0.5MPa, and the tangential flow velocity of the liquid is 2.5-3.0m / s. After the liquid distiller's grains liquid is subjected to membrane treatment and separation, the concentrated phase retentate with a water content of about 85% and the dilute phase permeate with a water content of about 99.5% are obtained. The concentrated phase retentate contains flavor substances such as tetramethylpyrazine and ethyl hexanoate, and is used as a raw material for flavor substances in subsequent processes. The dilute phase permeate is used as recycled water and membrane flushing liquid for recycling. The membrane is back-flushed with the dilute phase permeate every 30 minutes to prevent the membrane from being blocked.

[0026] Further, the device (not shown in the drawings) used for the moisture removal and dehydration in steps S2 and S3 comprises: The drying channel comprises a first channel, a second channel and a third channel which are communicated with each other in sequence, and the first channel, the second channel and the third channel can be adjusted in temperature by a temperature regulator. A conveying belt is arranged in the drying channel and conveys the 55-60% water content of the vinasse along the length direction of the drying channel, and the 55-60% water content of the vinasse sequentially passes through the first channel, the second channel and the third channel, wherein, In step S2, the vinasse is dehumidified and dried at a temperature of 52-55°C to obtain the preliminary dried vinasse with a water content of 38-42%, which is completed in the first channel; In step S3, the preliminary dried vinasse is dehumidified and dried at a temperature of 72-78°C to obtain the available vinasse with a water content of 12%, which is completed in the third channel.

[0027] In the above technical solution, the conveying speed of the conveying belt is 0.3 m / min, and uniformly penetrates the drying channel, and there is no physical interruption between the first channel, the second channel and the third channel. Whether in the first channel or the third channel, if the corresponding drying index is not completed, the conveying speed can be adjusted according to the actual situation.

[0028] In some embodiments, the length of the first channel is not greater than 7.5 m, in some embodiments, the length of the second channel is 2-2.5 m, and in other embodiments, the length of the third channel is 7.5-15 m.

[0029] Further, the conveying belt is a mesh belt, the mesh diameter of the mesh belt is 2 mm, and the air permeability is not less than 90%. In order to facilitate detection, in some embodiments, an infrared thickness sensor (accuracy ±1 mm) is installed below the mesh belt to feedback the material uniformity in real time.

[0030] Further, temperature sensors and humidity sensors are arranged in the first channel and the third channel to detect the humidity of the liquor vinasse and the temperature in the channel.

[0031] Application Example 1 A dehydrating and drying method of liquor vinasse is provided, which specifically comprises the following steps: 1) Pretreatment: The original liquor vinasse is sent to a double-layer vibrating screen (pore size 5 mm, material 316L stainless steel, corrosion prevention) by a screw conveyor to remove part of the rice hull, stone, glass and other impurities.

[0032] 0.1% citric acid is added to the screened liquor vinasse to maintain the pH value of the liquor vinasse between 4.5-5 to ensure the activity of flavor substances in the liquor vinasse.

[0033] 2) Spiral filter dewatering: The screened lees is sent to a screw filter press by a belt conveyor for preliminary dewatering (the screw filter press is different from the extruder in the previous scheme, the pressure of the screw filter press is smaller, the pressure is 0.8 MPa, and only preliminary dewatering is performed), and after the lees is preliminarily dewatered by the filter press, the lees is composed of extruded dregs containing 55% of water and liquid lees containing 90% of water.

[0034] 3) Membrane separation of liquid lees: After the liquid lees is sent to a lees liquid storage tank after removal of suspended solids by a bag filter, the liquid lees is sent into a ceramic membrane assembly by a screw pump, the ceramic membrane is made of α-alumina, the pore size is 50 kDa, the operating pressure is 0.3 MPa, and the tangential flow velocity of the liquid lees is 2.5 m / s. After the liquid lees is separated by membrane treatment, a concentrated phase retentate containing 85% of water and a dilute phase permeate containing 99.5% of water are obtained. The concentrated phase retentate contains flavor substances such as tetramethylpyrazine and ethyl hexanoate, and is used as a raw material for flavor substances in subsequent processes. The dilute phase permeate is used as In order to reuse the water and the flushing liquid of the membrane, the membrane is flushed in reverse direction by the dilute phase permeate every 30 minutes to prevent the membrane from being blocked.

[0035] 4) Low-temperature heat pump gradient drying of extruded solid dregs: The solid extruded dregs containing 55% of water are conveyed by a screw conveyor, uniformly laid on a stainless steel mesh belt of a low-temperature heat pump dryer by a rotating material distributing disc, the mesh belt has a pore size of 2 mm, an air permeability of > 90%, and the material is laid at a thickness of about 5 cm to ensure uniform heating of the dregs in the drying chamber and avoid local over-wetting or caking. An infrared thickness sensor (accuracy ± 1 mm) is installed below the mesh belt to real-time feedback the uniformity of the material.

[0036] The low-temperature heat pump drying chamber has a continuous tunnel structure, and is divided into a front section (first channel) and a rear section (third channel) by a partition to form a temperature and humidity gradient. The temperature in the first channel (0-7.5 m) is 55°C, and the temperature in the third channel (7.5-15 m) is 75°C. A 2 m transition zone (second channel, temperature 55→75°C) is arranged in the middle. A stainless steel mesh belt (speed 0.3 m / min) uniformly penetrates through the entire drying chamber. The dregs continuously move from the front section to the rear section without physical interruption. Temperature and humidity sensors are arranged at the outlets of the front and rear sections to real-time monitor the state (water content) of the dregs. If the water content does not meet the standard, the speed of the mesh belt is reduced (minimum 0.2 m / min) to extend the drying time. In the first channel, the free water in the capillary tubes and the water adhered to the surface of the dregs are removed, and the water content is reduced to about 40%. In the third channel, the adsorbed water and part of the micropore combined water combined with the fibers and proteins in the dregs are removed, and the water content is reduced to about 12%.

[0037] 5) Condensed water: The condensed water generated during the drying process is reused within the factory and does not need to be discharged.

[0038] 6) finished material: After the distiller's grains are dewatered to a moisture content of 12%, they are sent to the crushing and packaging section to perform the next process operation.

[0039] Comparative Example 1 A dewatering and drying method for distiller's grains is provided, which is the same as that in Application Example 1, except that in step 1), 0.1% citric acid is added to the sieved distiller's grains to maintain the pH value of the distiller's grains between 4.5 and 5 to ensure the activity of flavor substances in the distiller's grains.

[0040] Comparative Example 2 A dewatering and drying method for distiller's grains is provided, which directly uses an extrusion method for dewatering and drying.

[0041] 1) Feeding: the sieved distiller's grains (pH 4.5-5.0, containing 0.1% citric acid) are sent into the feed inlet of the filter press by a belt conveyor at a feeding speed matching the processing capacity of the previous vibrating screen.

[0042] 2) Single-stage pressing of the distiller's grains by a screw extruder (pressure greater than 5 MPa) for dewatering.

[0043] Comparative Example 3 A dewatering and drying method for distiller's grains is provided, which directly uses a hot air drying method for dewatering and drying the sieved distiller's grains (pH 4.5-5.0, containing 0.1% citric acid), and the drying conditions are as follows: the distiller's grains are dried by hot air heated to 1000°C by natural gas combustion.

[0044] Comparative Example 4 A dewatering and drying method for distiller's grains is provided, which is the same as that in Application Example 1, except that in step 4), only the first channel is set, and the temperature is 55°C, and the distiller's grains are dewatered to a moisture content of 12%.

[0045] Comparative Example 5 A dewatering and drying method for distiller's grains is provided, which is the same as that in Application Example 1, except that in step 4), only the third channel is set, and the temperature is 75°C, and the distiller's grains are dewatered to a moisture content of 12%.

[0046] Performance test and results The distiller's grains obtained in Example 1 and Comparative Examples 1-5 are detected, and the detection results are shown in Table 1: Table 1

[0047] Conclusion: From Table 1, it can be seen that the application is through the technical chain of "low-temperature dehydration-precision membrane separation-closed loop water reuse", while reducing the comprehensive energy consumption by 65%, the added value of distiller's grains is improved, the flavor substances in the distiller's grains are retained, and the problems of VOCs emission and wastewater zero emission are completely solved, the wastewater is close to zero emission, and a carbon neutral benchmark solution is provided for the wine brewing industry.

[0048] The specific raw materials in the application are all existing substances, which can be directly purchased from the market.

[0049] The above are only preferred embodiments of the present application, and are not used to limit the protection scope of the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for dewatering and drying white liquor stillage, characterized by, The application relates to a white spirit lees drying method. S1, white spirit lees are extruded and dewatered, the extrusion intensity is not greater than 0.8 MPa, and lees residue with a water content of 55-60% is obtained; S2, the lees residue is dewatered and dried at a temperature of 52-55 DEG C, and preliminary dried lees residue with a water content of 38-42% is obtained; S3, the preliminary dried lees residue is dewatered and dried at a temperature of 72-78 DEG C, and available lees residue with a water content of 12% is obtained.

2. The method of dewatering and drying white lees according to claim 1, characterized in that, Before the white spirit lees are extruded and dewatered in step S1, the white spirit lees need to be screened to remove impurities in the white spirit lees.

3. The method for dewatering and drying white lees according to claim 1, characterized by, Before the white spirit lees are extruded and dewatered in step S1, citric acid is added to the white spirit lees to maintain the pH of the white spirit lees to be 4.5-5.

4. The white lees dewatering drying method according to claim 3, characterized by, The mass fraction of the added citric acid is 0.1-0.15%.

5. The white lees dewatering drying method according to claim 1, characterized by, After the white spirit lees are extruded in step S1, not only lees residue with a water content of 55-60% is obtained, but also liquid lees liquor with a water content of 85-95% is obtained, the liquid lees liquor is subjected to membrane treatment and separation, and concentrated phase retentate and dilute phase permeate are obtained for recycling.

6. The method for dewatering and drying white lees according to claim 1, characterized by, The device used for dewatering and drying in steps S2 and S3 comprises: a drying channel which comprises a first channel, a second channel and a third channel which are communicated with each other in sequence, and the first channel, the second channel and the third channel can be adjusted in temperature by a temperature regulator; a conveying belt which is arranged in the drying channel and conveys the lees residue with a water content of 55-60% along the length direction of the drying channel, and the lees residue with a water content of 55-60% passes through the first channel, the second channel and the third channel in sequence, wherein in step S2, the lees residue is dewatered and dried at a temperature of 52-55 DEG C, and preliminary dried lees residue with a water content of 38-42% is obtained, and the process is completed in the first channel; in step S3, the preliminary dried lees residue is dewatered and dried at a temperature of 72-78 DEG C, and available lees residue with a water content of 12% is obtained, and the process is completed in the third channel.

7. The method of dewatering and drying white lees according to claim 6, characterized in that, The length of the first channel is not greater than 7.5 m; and / or the length of the second channel is 2-2.5 m; and / or the length of the third channel is 7.5-15 m.

8. The method for dewatering and drying white lees according to claim 6, characterized by, The conveying belt is a mesh belt, the mesh belt has a pore size of 2 mm, and the air permeability is not less than 90%.

9. The method of dewatering and drying white lees according to claim 6, characterized by, The first channel and the third channel are each provided with a temperature sensor and a humidity sensor.

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