An extraction apparatus and extraction method for refining liquid methionine

Abstract

The present application belongs to the field of chemical separation technology, and relates to an extraction device and an extraction method for refining liquid methionine. The extraction device comprises a tower body, a stirring shaft, a transmission part, a fixed ring, a rotating disc and an inter-stage rotating baffle. The extraction device and the extraction method for refining liquid methionine can efficiently separate a solution system containing liquid methionine and ammonium sulfate, significantly improve the separation efficiency of liquid methionine and ammonium sulfate, effectively improve the product purity of liquid methionine, and reduce the energy consumption of the subsequent separation process.

Description

Technical Field

[0001] This invention belongs to the field of chemical separation technology, and relates to an extraction device and extraction method for refining liquid methionine. Background Technology

[0002] Liquid methionine, chemically known as 2-hydroxy-4-methylthiobutyric acid, is an important feed additive. Industrially, it is mainly prepared by hydrolyzing cyanohydrin (2-hydroxy-4-methylthiobutyronitrile) in the presence of sulfuric acid, resulting in a mixed solution system of liquid methionine and ammonium sulfate. In this system, liquid methionine is the target product, and ammonium sulfate is a byproduct. Therefore, achieving efficient separation of liquid methionine and ammonium sulfate in this system has significant industrial application value.

[0003] Liquid-liquid extraction is one of the feasible technical routes for treating liquid methionine-ammonium sulfate solution system. This material system has certain special characteristics, specifically: (1) high viscosity. The system has a certain viscosity, which leads to high resistance to droplet movement and low mass transfer rate in conventional extraction towers; (2) easy crystallization. The concentration of ammonium sulfate in the aqueous phase is high, which easily reaches supersaturation and precipitates ammonium sulfate solid microcrystals.

[0004] Based on the above material characteristics, special requirements are put forward for extraction equipment and extraction process. Summary of the Invention

[0005] The primary objective of this invention is to provide an extraction device for refining liquid methionine, which enables efficient extraction and separation of a solution system containing liquid methionine and ammonium sulfate, significantly improving the separation efficiency of liquid methionine and ammonium sulfate, effectively enhancing the purity of the liquid methionine product, and reducing energy consumption in subsequent separation processes.

[0006] To achieve this objective, in a basic implementation, the present invention provides an extraction apparatus for refining liquid methionine, the extraction apparatus comprising a tower body, a stirring shaft, a transmission component, a fixed ring, a turntable, and interstage rotating baffles. Inside the tower, a vertical stirring shaft is arranged along the central axis, and the stirring shaft can rotate under the drive of the transmission part connected to it. Multiple fixing rings are respectively horizontally connected and installed on the inner wall of the tower body; A turntable, horizontally connected to the stirring shaft, is provided between two adjacent fixed rings. Each of the aforementioned fixed rings has a horizontally oriented interstage rotating baffle connected to the stirring shaft at its hollow center, and the interstage rotating baffle has an opening.

[0007] In a preferred embodiment, the present invention provides an extraction apparatus for refining liquid methionine, wherein the transmission part includes a reducer, a frame, a drive motor, a coupling, and a frequency converter. The reducer is mounted on the frame, the drive motor is connected to the reducer, the output shaft of the reducer is connected to the upper end of the stirring shaft via the coupling, and the frequency converter is used to drive the motor to change its frequency.

[0008] In a preferred embodiment, the present invention provides an extraction apparatus for refining liquid methionine, wherein: The inner diameter of the retaining ring is larger than the diameter of the turntable (thus providing operating space for the installation and removal of the turntable); and / or The opening ratio of the interstage rotating baffle is 40-70% (preferably 40-60%).

[0009] In a preferred embodiment, the present invention provides an extraction apparatus for refining liquid methionine, wherein the sieve holes on the interstage rotating baffles effectively suppress interstage axial backmixing while enhancing the mixing intensity of materials within each stage and strengthening the mass transfer process between the two phases. The diameter of the sieve holes is 1-10 mm, preferably 3-6 mm.

[0010] In a preferred embodiment, the present invention provides an extraction apparatus for refining liquid methionine, wherein: The height-to-diameter ratio of the tower body is 8-14:1 (preferably 9-12:1); and / or The fixed ring, the turntable, and the interstage rotating baffles have 20-80 layers (preferably 30-60 layers); and / or The distance between adjacent interstage rotating baffles and turntables is 20-100mm (preferably 40-70mm).

[0011] In a preferred embodiment, the present invention provides an extraction apparatus for refining liquid methionine, wherein the extraction apparatus further includes a skirt and / or a cap. The skirt base is located below the tower body and is used to support the tower body; The end cap is positioned above the tower body and is used to seal the tower body.

[0012] In a preferred embodiment, the present invention provides an extraction apparatus for refining liquid methionine, wherein the extraction apparatus further includes a material inlet, an extractant inlet, a light phase outlet, and a heavy phase outlet disposed on the wall of the column body. The material inlet is used to introduce a solution containing liquid methionine and ammonium sulfate into the tower body; The extractant inlet is used to introduce extractant into the tower body; The light phase outlet is used to discharge the organic phase containing liquid methionine from the tower body; The heavy phase outlet is used to discharge the aqueous phase containing ammonium sulfate from the tower body.

[0013] In a preferred embodiment, the present invention provides an extraction apparatus for refining liquid methionine, wherein the material inlet and the light phase outlet are located above the uppermost fixing ring at the top of the column, and the extractant inlet and the heavy phase outlet are located below the lowermost fixing ring at the bottom of the column. This allows the material and extractant to contact each other countercurrently within the column.

[0014] The second objective of this invention is to provide an extraction method for refining liquid methionine using the extraction equipment described above. This method enables efficient extraction and separation of a solution system containing liquid methionine and ammonium sulfate using the extraction equipment described above, significantly improving the separation efficiency of liquid methionine and ammonium sulfate, effectively enhancing the purity of the liquid methionine product, and reducing energy consumption in subsequent separation processes.

[0015] To achieve this objective, in a basic implementation, the present invention provides an extraction method for refining liquid methionine using the extraction equipment described above. The extraction method involves passing a solution containing liquid methionine and ammonium sulfate, along with an extractant, into the tower for multi-stage extraction, and discharging the extracted organic phase containing liquid methionine and the aqueous phase containing ammonium sulfate from the tower respectively.

[0016] The principle of the extraction method of the present invention is as follows: (1) A solution containing liquid methionine-ammonium sulfate and an extractant are introduced into a rotating disc extraction tower respectively; (2) Under the shear force of the rotating disc extraction tower, the two phases are dispersed into fine droplets, fully mixed and mass transferred, and liquid methionine is transferred from the aqueous phase to the organic phase; (3) The mixed droplets continuously aggregate during the flow in the tower, and finally form a clear two-phase stratification in the tower by relying on the density difference between the two phases. The light phase is discharged from the top of the tower and the heavy phase is discharged from the bottom of the tower. The organic phase rich in liquid methionine and the aqueous phase containing ammonium sulfate are collected respectively, thereby achieving efficient separation of liquid methionine and ammonium sulfate.

[0017] In a preferred embodiment, the present invention provides an extraction method for refining liquid methionine using the extraction equipment described above, wherein: The solution containing liquid methionine and ammonium sulfate has a pH of 1-6 (preferably 2-4), wherein the concentrations of liquid methionine and ammonium sulfate are 30-50 wt% and 20-30 wt%, respectively; and / or The extractant is selected from one or more of acetone, methyl isopropyl ketone, methyl isobutyl ketone, diethyl ether, and isopropanol (preferably methyl isobutyl ketone); and / or The volume ratio of the extractant to the solution containing liquid methionine and ammonium sulfate is 1-3:1 (preferably 1.5-2:1).

[0018] In a preferred embodiment, the present invention provides an extraction method for refining liquid methionine using the extraction equipment described above, wherein the multi-stage extraction temperature is 30-70°C (preferably 45-55°C) and the pressure is atmospheric pressure.

[0019] In a preferred embodiment, the present invention provides an extraction method for refining liquid methionine using the extraction equipment described above, wherein: The rotational speed of the turntable is 1-50 r / min (preferably 20-25 r / min); and / or The residence time of the solution containing liquid methionine and ammonium sulfate in the tower is 20-60 min (preferably 25-35 min).

[0020] In a preferred embodiment, the present invention provides an extraction method for refining liquid methionine using the extraction equipment described above, wherein the light phase (the organic phase containing liquid methionine) is extracted by overflow, and the interface between the light phase and the heavy phase (the aqueous phase containing ammonium sulfate) is precisely controlled by an interface gauge.

[0021] The beneficial effects of this invention are that, by using the extraction equipment and extraction method for refining liquid methionine of this invention, a solution system containing liquid methionine and ammonium sulfate can be efficiently extracted and separated, significantly improving the separation efficiency of liquid methionine and ammonium sulfate, effectively improving the product purity of liquid methionine, and reducing the energy consumption of subsequent separation processes.

[0022] This invention, based on the high viscosity and easy crystallization properties of the liquid methionine-ammonium sulfate system, uses a rotating disc extraction tower instead of a traditional extraction tower for extraction and separation, and has the following specific beneficial technical effects: (1) Compared with existing extraction and separation equipment, the rotary disc extraction tower uses the shear force generated by the high-speed rotation of the disc to disperse the material into fine droplets, increasing the mass transfer area and significantly improving the extraction efficiency.

[0023] (2) Compared with existing extraction and separation equipment, the rotary disc extraction tower adopts a structure with alternating fixed rings and rotating discs. The fixed rings divide the tower body into multiple independent mixing chambers, which effectively suppresses axial back mixing between stages and improves the mass transfer efficiency of the two phases.

[0024] (3) Compared with existing extraction and separation equipment, the open flow channel structure of the rotary extraction tower allows the liquid containing solid microcrystals to pass through smoothly without clogging, significantly extending the continuous operation cycle of the equipment and greatly reducing maintenance costs.

[0025] (4) Compared with existing extraction and separation equipment, the residual amount of ammonium sulfate in the oil phase is significantly reduced, the product purity is greatly improved, the processing load and energy consumption of the subsequent refining stage are reduced, and good economic benefits are achieved.

[0026] (5) The extraction equipment of the present invention has a simple structure, stable operation and reliable scale-up. It can be widely used in the industrial separation and purification process of liquid methionine and has significant industrial application value and promotion prospects.

[0027] In summary, this invention addresses the high-viscosity, easily crystallizing liquid methionine-ammonium sulfate solution generated during the preparation of liquid methionine. It employs a rotating disc extraction tower as the extraction device to purify and separate this solution system. This equipment utilizes the rotating shearing action of the disc to overcome the mass transfer resistance of the high-viscosity system, and the open flow channel structure within the tower prevents ammonium sulfate crystallization blockage. Furthermore, the rotation speed is adjustable, offering high operational flexibility. Compared with existing technologies, this invention significantly improves the separation efficiency of liquid methionine and ammonium sulfate, as well as the purity of the liquid methionine product. It also boasts advantages such as stable operation, anti-clogging properties, and suitability for industrial applications. Attached Figure Description

[0028] Figure 1 This is an exemplary structural diagram of the extraction apparatus for refining liquid methionine according to the present invention.

[0029] Figure 2 The diagram shows the structural composition of the packed extraction tower used in Comparative Example 1, including a skirt 101, a tower body 102, a material distributor 103, a first packing layer 104, a liquid redistributor 105, a second packing layer 106, an extractant distributor 107, a material inlet 108, an extractant inlet 109, a light phase outlet 110, and a heavy phase outlet 111. Detailed Implementation

[0030] An exemplary composition of the extraction apparatus for refining liquid methionine according to the present invention is as follows: Figure 1 As shown, it includes a skirt 1, a tower body 2, a stirring shaft 3, a fixing ring 4, a turntable 5, a head 6, a transmission part 7, a material inlet 8, an extractant inlet 9, a light phase outlet 10, a heavy phase outlet 11, and an interstage rotating baffle 12.

[0031] Inside the tower body 2, a vertical stirring shaft 3 is installed along the central axis. The stirring shaft 3 can rotate under the drive of the transmission part 7 connected to it.

[0032] The transmission part 7 includes a reducer, a frame, a drive motor, a coupling, and a frequency converter. The reducer is mounted on the frame, the drive motor is connected to the reducer, the output shaft of the reducer is connected to the upper end of the stirring shaft 3 through the coupling, and the frequency converter is used to change the frequency of the drive motor.

[0033] Multiple fixing rings 4 are horizontally connected and installed at equal intervals on the inner wall of the tower body 2.

[0034] A horizontally oriented turntable 5 is positioned at the center of two adjacent fixed rings 4, connected to the stirring shaft 3. The inner diameter of the fixed ring 4 is larger than the diameter of the turntable 5.

[0035] At the center of the hollow core of each fixed ring 4, a horizontally oriented interstage rotating baffle 12 is connected to the stirring shaft 3. The interstage rotating baffle 12 has openings with an opening ratio of 40-70% (preferably 40-60%). The sieve holes on the interstage rotating baffle 12 effectively suppress axial back-mixing between stages, while simultaneously enhancing the mixing intensity of materials within each stage and strengthening the mass transfer process between the two phases. The diameter of the sieve holes is 1-10 mm, preferably 3-6 mm.

[0036] The height-to-diameter ratio of the tower body 2 is 8-14:1 (preferably 9-12:1). The number of layers (number) of the fixing ring 4, turntable 5, and interstage rotating baffle 12 is 20-80 (preferably 30-60). The distance between adjacent interstage rotating baffles 12 and turntable 5 is 20-100mm (preferably 40-70mm).

[0037] A skirt support 1 is located below the tower body 2 to support it. A head 6 is located above the tower body 2 to seal the tower body 2 and the stirring shaft 3. The upper wall of the topmost fixing ring 4 of the tower body 2 has a material inlet 8 (for introducing a solution containing liquid methionine and ammonium sulfate into the tower body 2) and a light phase outlet 10 (for discharging the organic phase containing liquid methionine from the tower body 2). The lower wall of the bottommost fixing ring 4 of the tower body 2 has an extractant inlet 9 (for introducing the extractant into the tower body 2) and a heavy phase outlet 11 (for discharging the aqueous phase containing ammonium sulfate from the tower body 2). This ensures that the material and extractant are in countercurrent contact within the tower body 2.

[0038] The exemplary extraction apparatus for refining liquid methionine of the present invention described above, and the exemplary extraction method for refining liquid methionine, involves passing a solution containing liquid methionine, ammonium sulfate, and an extractant into a tower body 2 for multi-stage extraction, and discharging the extracted organic phase containing liquid methionine and the aqueous phase containing ammonium sulfate from the tower body 2 respectively.

[0039] in: The solution containing liquid methionine and ammonium sulfate has a pH of 1-6 (preferably 2-4), wherein the concentrations of liquid methionine and ammonium sulfate are 30-50 wt% and 20-30 wt%, respectively. The extractant is selected from one or more of acetone, methyl isopropyl ketone, methyl isobutyl ketone, diethyl ether, and isopropanol (preferably methyl isobutyl ketone). The volume ratio of the extractant to the solution containing liquid methionine and ammonium sulfate is 1-3:1 (preferably 1.5-2:1). The temperature for multi-stage extraction is 30-70℃ (preferably 45-55℃), and the pressure is atmospheric pressure. The rotational speed of turntable 5 is 1-50 r / min (preferably 20-25 r / min); The residence time of the solution containing liquid methionine and ammonium sulfate in tower 2 is 20-60 min (preferably 25-35 min). The light phase (organic phase containing liquid methionine) is extracted by overflow, and the boundary between the light phase and the heavy phase (aqueous phase containing ammonium sulfate) is precisely controlled by a boundary gauge.

[0040] Examples of applications of the above-described exemplary extraction apparatus and extraction method of the present invention are as follows.

[0041] Example 1: In a reactor equipped with a stirrer and temperature control device, a sulfuric acid base solution is prepared beforehand. After heating to the set temperature, a cyanohydrin solution is added dropwise to the reactor at a constant rate, and a hydration reaction is carried out under constant temperature conditions to convert the cyano groups into amide groups. After hydration, process water is added and the temperature is raised to the hydrolysis temperature to further hydrolyze the amide intermediate into the free target product and ammonium bisulfate. After hydrolysis, ammonia water is added dropwise to the system for neutralization, converting the ammonium bisulfate into ammonium sulfate.

[0042] Secure the separatory funnel to the iron stand and close the stopcock. Accurately measure 200 mL of the liquid methionine-ammonium sulfate solution obtained above (liquid methionine content 40.53 wt%, ammonium sulfate content 27.21 wt%) using a graduated cylinder and add it through the top opening of the separatory funnel. Then, measure 400 mL of methyl isobutyl ketone (MIBK) using a graduated cylinder and add it through the top opening as well. Replace the glass stopper, remove the separatory funnel, press the glass stopper firmly with your right palm, hold the lower stopcock with your left hand, and invert the separatory funnel. First, open the lower stopcock to release air, then shake vigorously for 3 minutes to ensure sufficient contact between the two phases. Invert again to release air, and repeat the shaking 2-3 times. After shaking, return the separatory funnel to the iron stand, open the glass stopper, and let it stand for 5-15 minutes until the interface between the two phases is clear. Then, open the lower stopcock, release the lower liquid from the bottom opening into an Erlenmeyer flask, and pour the upper organic phase from the top opening into another Erlenmeyer flask. Tests showed that the single extraction yield of liquid methionine was 45.15%, the residual amount of liquid methionine in the aqueous phase after extraction was 16.32 wt%, and the amount of ammonium sulfate entrained in the organic phase was 10.98 wt%.

[0043] Example 2: A liquid methionine-ammonium sulfate solution (pH=4.2) was used as the heavy phase, consisting of 41.68 wt% liquid methionine, 26.21 wt% ammonium sulfate, 31.93 wt% water, and 0.18 wt% other impurities. This solution was introduced at a flow rate of 15 L / h through the material inlet 8 at the top of the extraction equipment (rotary disc extraction tower). Methyl isobutyl ketone (MIBK) was used as the extractant, introduced at a flow rate of 30 L / h through the extractant inlet 9 at the bottom of the rotary disc extraction tower. The volume ratio of extractant to material was controlled at 2:1, the extraction temperature was 45℃, the rotation speed of the rotary disc 5 was 20 r / min, and the operating pressure was atmospheric pressure. The rotating disc extraction column has a height-to-diameter ratio of 10:1, with 40 layers in the rotating disc 5, 40 layers in the fixed ring 4, and 40 layers in the interstage rotating baffle 12. The distance between adjacent interstage rotating baffles 12 and rotating discs 5 is 50 mm, the opening ratio of the interstage rotating baffles 12 is 50%, and the sieve diameter is 5 mm. The residence time of the material containing liquid methionine and ammonium sulfate is 30 min. The upper organic phase (mainly composed of liquid methionine and methyl isobutyl ketone) and the lower aqueous phase (mainly composed of water and ammonium sulfate) are collected separately. High-performance liquid chromatography (HPLC) analysis shows that the single extraction yield of liquid methionine is 63.77%, the residual amount of liquid methionine in the aqueous phase after extraction is 10.32 wt%, and the amount of ammonium sulfate entrained in the organic phase is 5.98 wt%.

[0044] Example 3: This embodiment is basically the same as Example 2, except that the extraction temperature is adjusted to 60℃. Under these conditions, the single extraction yield of liquid methionine is 61.57%, the residual amount of liquid methionine in the aqueous phase after extraction is 10.65 wt%, and the amount of ammonium sulfate entrained in the organic phase is 7.86 wt%.

[0045] Example 4: This embodiment is basically the same as Embodiment 2, except that the rotation speed of the turntable 5 is 50 r / min. Under these conditions, the single extraction yield of liquid methionine is 60.61%, the residual amount of liquid methionine in the aqueous phase after extraction is 12.06 wt%, and the amount of ammonium sulfate entrained in the organic phase is 8.02 wt%.

[0046] Comparative Example 1: This comparative example uses a packed extraction tower (composition and structure as follows) Figure 2(As shown) Liquid methionine-ammonium sulfate solution was extracted and separated under basically the same material composition and operating conditions as in Example 2. The height-to-diameter ratio of the packed extraction column was 10:1, the column body material was 316L, the packing material was bulk material, Pall rings were selected, the packing density was 1.2 kg / L, the porosity was 90%, and the opening rate of the support plate below the packing layer at the bottom of the column was >80%; the height of each packing layer was 0.5 m, and a liquid redistributor 105 was installed between the sections. Under these conditions, the single extraction yield of liquid methionine was 40.69%, the residual amount of liquid methionine in the aqueous phase after extraction was 18.17 wt%, and the amount of ammonium sulfate entrained in the organic phase was 10.32 wt%.

[0047] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims and their equivalents, this invention is also intended to include these modifications and variations. The above embodiments or implementations are merely illustrative examples of this invention, and it can also be implemented in other specific ways or forms without departing from its gist or essential characteristics. Therefore, the described embodiments should be considered illustrative rather than limiting in any respect. The scope of this invention should be defined by the appended claims, and any changes equivalent to the intent and scope of the claims should also be included within the scope of this invention.

Claims

1. An extraction apparatus for refining liquid methionine, characterized in that: The extraction equipment includes a tower body, a stirring shaft, a transmission system, a fixed ring, a turntable, and interstage rotating baffles. Inside the tower, a vertical stirring shaft is arranged along the central axis, and the stirring shaft can rotate under the drive of the transmission part connected to it. Multiple fixing rings are respectively horizontally connected and installed on the inner wall of the tower body; A turntable, horizontally connected to the stirring shaft, is provided between two adjacent fixed rings. Each of the aforementioned fixed rings has a horizontally oriented interstage rotating baffle connected to the stirring shaft at its hollow center, and the interstage rotating baffle has an opening.

2. The extraction apparatus according to claim 1, characterized in that: The transmission component includes a speed reducer, a frame, a drive motor, a coupling, and a frequency converter. The speed reducer is mounted on the frame, the drive motor is connected to the speed reducer, the output shaft of the speed reducer is connected to the upper end of the stirring shaft via the coupling, and the frequency converter is used to drive the motor to change its frequency.

3. The extraction apparatus according to claim 1, characterized in that: The inner diameter of the fixed ring is larger than the diameter of the turntable; and / or The opening ratio of the interstage rotating baffle is 40-70%.

4. The extraction apparatus according to claim 1, characterized in that: The extraction apparatus further includes a skirt and / or a head. The skirt base is located below the tower body and is used to support the tower body; The end cap is positioned above the tower body and is used to seal the tower body.

5. The extraction apparatus according to claim 1, characterized in that: The extraction equipment also includes a material inlet, an extractant inlet, a light phase outlet, and a heavy phase outlet disposed on the wall of the tower body. The material inlet is used to introduce a solution containing liquid methionine and ammonium sulfate into the tower body; The extractant inlet is used to introduce extractant into the tower body; The light phase outlet is used to discharge the organic phase containing liquid methionine from the tower body; The heavy phase outlet is used to discharge the aqueous phase containing ammonium sulfate from the tower body.

6. The extraction apparatus according to claim 5, characterized in that: The material inlet and the light phase outlet are located above the uppermost fixing ring at the top of the tower body, while the extractant inlet and the heavy phase outlet are located below the lowermost fixing ring at the bottom of the tower body.

7. An extraction method for refining liquid methionine using the extraction equipment described in any one of claims 1-6, characterized in that: The extraction method involves passing a solution containing liquid methionine and ammonium sulfate, along with an extractant, into the tower for multi-stage extraction. The extracted organic phase containing liquid methionine and the aqueous phase containing ammonium sulfate are then discharged from the tower.

8. The extraction method according to claim 7, characterized in that: The solution containing liquid methionine and ammonium sulfate has a pH of 1-6, wherein the concentrations of liquid methionine and ammonium sulfate are 30-50 wt% and 20-30 wt%, respectively; and / or The extractant is selected from one or more of acetone, methyl isopropyl ketone, methyl isobutyl ketone, diethyl ether, and isopropanol; and / or The volume ratio of the extractant to the solution containing liquid methionine and ammonium sulfate is 1-3:

1.

9. The extraction method according to claim 7, characterized in that: The multi-stage extraction is carried out at a temperature of 30-70℃ and a pressure of atmospheric pressure.

10. The extraction method according to claim 7, characterized in that: The rotational speed of the turntable is 1-50 r / min; and / or The residence time of the solution containing liquid methionine and ammonium sulfate in the tower is 20-60 minutes.

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